JP7774330B2 - Parts Transfer System and Parts Welding System - Google Patents

Description

This disclosure relates to a part transfer system and a part welding system.

In Patent Document 1, the parts supply device receives parts sent from the parts aligner via a tube in a parts holder attached to the tip of a rod, and then supplies the parts received by the parts holder to the target position by moving the rod forward.

JP 2018-192499 A (particularly FIG. 1)

In Patent Document 1, the tube connecting the part aligner and part supply device extends upward from the part aligner, then changes direction and extends downward to reach the part supply device. As a result, when the parts are sent from the part aligner to the part supply device via the tube, they must move from bottom to top within the tube, against gravity.

In order to move parts from bottom to top within the tube against gravity, the parts must be forced upwards using gas, necessitating a gas pressure-feeding mechanism that uses compressed air, etc. To install such a gas pressure-feeding device, a gas supply source is essential to supply gas to the gas pressure-feeding device.

The present disclosure has been made in light of these issues, and its purpose is to reduce the gas supply source in a part transfer system that transfers parts to a target position.

The part transfer system disclosed herein comprises a lifting mechanism that lifts parts from a lower position to an upper position, a chute that drops the parts sent from the upper position of the lifting mechanism, and a supply mechanism that receives the parts that have dropped from the chute with a stopper and supplies the parts received by the stopper to a destination position by advancing a rod, and the chute extends downward from the upper position of the lifting mechanism to the supply mechanism without returning upward.

With this configuration, parts are raised from the lower position to the upper position in the lifting mechanism, dropped from the upper position of the lifting mechanism down the chute, received by the stopper of the supply mechanism, and supplied to the target position by the advancement of the rod of the supply mechanism.

The chute extends downward from the top of the lifting mechanism to the supply mechanism without returning upward. From the top of the lifting mechanism to the supply mechanism, the parts naturally fall downward by gravity in the chute without returning upward.

This eliminates the need to install a gas pumping mechanism to pump gas to move parts from bottom to top against gravity in the chute. This reduces the need to use a gas supply source to supply gas to such a gas pumping device.

As a result, the gas supply source can be reduced in the part transfer system that transfers parts to their destination.

In one embodiment, the lifting mechanism includes an outer cylinder that extends vertically; a plurality of suction units arranged in a spiral shape on the inner surface of the outer cylinder with a central axis that extends vertically and that apply a magnetic field to the outer surface of the outer cylinder to attract the parts to the outer surface of the outer cylinder; a rotational drive unit that rotates the plurality of suction units around the central axis; and a restriction unit that restricts the rotational movement of the parts and moves them upward along the outer surface of the outer cylinder.

With this configuration, the part is attached to the outer surface of the outer cylinder by some of the multiple suction parts arranged in a spiral pattern. The suction parts rotate around their central axis, causing the part to rotate along the outer surface of the outer cylinder. However, the part's rotational movement is restricted by the restricting parts. In other words, even though the suction parts rotate, the part does not rotate.

The multiple suction parts are arranged in a spiral and the outer cylinder extends vertically, so as the multiple suction parts rotate and move, new suction parts appear one after another above the part. The part is drawn to the successive suction parts that appear, and moves upward along the outer surface of the outer cylinder.

The lifting mechanism allows parts to be lifted upward with a simple configuration.

In one embodiment, the lifting mechanism has a front/back sorting section that, based on the difference in the protruding thickness from the outer surface of the outer tube, allows the part to pass when the front surface faces the outer surface, but rejects the part to prevent it from passing when the back surface faces the outer surface.

With this configuration, the lifting mechanism can distinguish between the front and back sides of parts and convert them into a uniform posture.

In one embodiment, the lifting mechanism has a reservoir at the lower position for storing multiple parts.

This configuration allows the lifting mechanism to efficiently lift parts upward from the reservoir located in the lower position.

In one embodiment, the lifting mechanism has a direction changer that changes the direction of the part moving upward along the outer surface of the outer cylinder to downward at the upper position.

With this configuration, the part's direction can be changed from above to below using the direction changer located in the upper position of the lifting mechanism, allowing the part to be moved downward and smoothly sent to the chute for the subsequent process.

In one embodiment, the chute has a cylindrical member through which the part passes and a long plate member disposed inside the cylindrical member and extending along the cylindrical member, and the part slides along the long plate member.

With this configuration, the parts in the chute slide against the long plate member placed inside the tubular member, preventing direct contact between the parts and the tubular member, thereby minimizing damage to the tubular member.

Furthermore, because the parts fall smoothly downward through the chute, the need for a gas pumping device to pump the parts downward through the chute can be reduced, contributing to a reduction in the gas supply source.

In one embodiment, the cylindrical member is made of a flexible material, and the long plate member is made of a material that is harder than the material making up the cylindrical member and that is elastically deformable.

With this configuration, by bending the flexible tubular member, the elastically deformable long plate member can also be deformed. Furthermore, because the long plate member is harder than the tubular member, frictional resistance when the parts slide against the long plate member can be reduced, making it easier for the parts to slide against the long plate member. Even if the chute is made to snake, the parts can be dropped down the chute.

Furthermore, because the parts fall smoothly downward through the chute, the need for a gas pumping device to pump the parts downward through the chute can be reduced, contributing to a reduction in the gas supply source.

In one embodiment, the part has a protrusion on its back surface, and the protrusion of the part slides along the long plate member.

With this configuration, there is a concern that the cylindrical member may be damaged if the protruding portion of the part comes into contact with the cylindrical member in the chute. However, by having the protruding portion of the part slide against the long plate member, the protruding portion of the part is prevented from coming into direct contact with the cylindrical member, thereby minimizing damage to the cylindrical member.

Furthermore, because the parts fall smoothly downward through the chute, the need for a gas pumping device to pump the parts downward through the chute can be reduced, contributing to a reduction in the gas supply source.

In one embodiment, the supply mechanism has an actuator that moves the rod back and forth, and the actuator is an electric actuator.

With this configuration, the supply mechanism does not need to use a gas supply source to move the rod back and forth using the actuator.

In one embodiment, the supply mechanism includes the rod that supplies the part having a through hole to the target position by advancing it forward, a piston connected to the rod, a cylinder that houses the rod and the piston, a lid that closes the cylinder forward of the piston and through which the rod extends forward from the piston, and an actuator that moves the piston and the rod back and forth. The piston, the cylinder, and the lid define a gas chamber, and the rod includes: a gas outlet that is provided on the outer periphery of the front end of the rod that is inserted into the through hole of the part and through which gas is blown out; a gas inlet that is provided behind the gas outlet and through which the gas is introduced from the gas chamber; and a gas passage that extends back and forth inside the rod and through which the gas passes from the gas inlet to the gas outlet.

With this configuration, as the rod advances, the front end of the rod is inserted into the through-hole of the part. The part hung on the front end of the rod is supplied to the target position as the rod advances.

Gas is stored in the gas chamber, which is defined by the piston, cylinder, and lid. When the piston moves forward, the gas in the gas chamber is compressed. The gas compressed in the gas chamber is introduced into the gas inlet of the rod. The gas introduced into the gas inlet passes through a gas passage inside the rod and is blown out from a gas outlet on the outer periphery of the front end of the rod.

Gas is blown out from gas outlets on the outer periphery of the front end of the rod toward the part hanging from the front end of the rod. This holds the part in place at the front end of the rod.

The supply mechanism uses a gas chamber partitioned by a piston, cylinder, and lid, so gas can be blown out from the gas outlet to hold the part at the front end of the rod without using a gas supply source.

The part welding system according to the present disclosure comprises the part transfer system and a resistance welding machine, the resistance welding machine including a lower electrode and an upper electrode, the target position being between the lower electrode and the upper electrode, a guide pin protruding and retracting from the tip of at least one of the lower electrode and the upper electrode, the guide pin protruding from the tip due to the elastic force of an elastic member and retracting from the tip by being pressed against the elastic force of the elastic member.

At the target position, the guide pin can be extended and retracted from the tip of at least one of the lower electrode and upper electrode without using a gas supply source.

In one embodiment, the resistance welding machine includes a resistance welding machine actuator, which compresses a resistance welding machine gas chamber by moving the upper electrode downward and simultaneously moving a resistance welding machine piston located in a resistance welding machine cylinder downward. The resistance welding machine gas chamber is connected to the outer surface side of the guide pin, and the gas compressed in the resistance welding machine gas chamber escapes upward along the outer surface of the guide pin.

With this configuration, debris (such as welding dust) generated by resistance welding machines can be removed by blowing gas without using a gas supply source.

The present disclosure makes it possible to reduce the gas supply source in a part transfer system that transfers parts to a destination location.

FIG. 1 shows a chute and a supply mechanism in a nut transfer system according to this embodiment. FIG. 2 shows a lifting mechanism in the nut transfer system according to this embodiment. FIG. 3 shows the nut in a perspective view. FIG. 4 shows a perspective view of the outer cylinder of the lifting mechanism. FIG. 5 shows a perspective view of the shaft and magnet in the lifting mechanism. FIG. 6 is a cross-sectional view taken along line VI of FIG. 4, showing a state in which the surface of the nut faces the outer surface of the outer cylinder in the lifting mechanism. FIG. 7 is a view equivalent to FIG. 6 showing a state in which the back surface of the nut faces the outer surface of the outer cylinder in the lifting mechanism. FIG. 8 shows the attitude change guide of the lifting mechanism as seen from the arrow VIII in FIG. FIG. 9 shows a cross-sectional view of the direction change guide of the lifting mechanism taken along line IX of FIG. FIG. 10 shows the chute in an X-ray cross section of FIG. FIG. 11 shows a front view of the nut feeding mechanism before the rod is inserted into the threaded hole of the nut. FIG. 12 shows a front view of the nut feeding mechanism after the rod has been inserted into the threaded hole in the nut. FIG. 13 shows a front view of the nut feeding mechanism at the moment when the rod feeds the nut to the target position. FIG. 14 shows a front view of the nut feeding mechanism after the rod has retracted from its destination position. FIG. 15 shows a perspective view of the nut receiver. FIG. 16 shows the rod in plan view. FIG. 17 shows the sealing mechanism in side view. FIG. 18 shows a front view of the sealing mechanism. FIG. 19 shows the lower electrode unit of a resistance welding machine. FIG. 20 shows a bolt transport system according to another embodiment. FIG. 21 shows a resistance welding machine according to another embodiment.

Embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the present disclosure, its applications, or its uses.

<Nut welding system>
A nut welding system S as a parts welding system according to this embodiment will be described. The nut welding system S includes a nut transfer system 1 as a parts transfer system, and a resistance welder 100.

<Nut transfer system>
A nut transfer system 1 as a part transfer system according to this embodiment will be described. Fig. 1 shows a chute 3 and a supply mechanism 4 in the nut transfer system 1 according to this embodiment. Fig. 2 shows a lifting mechanism 2 in the nut transfer system 1 according to this embodiment.

The nut transfer system 1 comprises a lifting mechanism 2, a chute 3, and a supply mechanism 4. The nut transfer system 1 is applied to a resistance welding machine 100. The nut transfer system 1 transfers a nut N as a part to a target position J between a lower electrode 104 and an upper electrode 109 in the resistance welding machine 100.

<Nut>
FIG. 3 shows a perspective view of the nut N. The nut transfer system 1 uses the nut N as a part to be transferred. The nut N is a rectangular weld nut. The nut N has a main body N1 and four protrusions N3. The main body N1 has a predetermined thickness t. The main body N1 is approximately rectangular. The front surface N1a and the back surface N1b of the main body N1 are parallel to each other and are approximately square. The four protrusions N3 are provided at the four corners of the back surface N1b of the main body N1. The protrusions N3 protrude toward the back surface N1b.

The overall thickness T of the nut N is the thickness t of the main body N1 alone plus the protruding dimension of the protrusion N3. The nut N has a screw hole N2 as a through hole. The screw hole N2 penetrates the center of the main body N1. The main body N1 of the nut N has four side surfaces N1c. The side surfaces N1c connect the front surface N1a and the back surface N1b of the main body N1. The distance between two opposing side surfaces N1c of the main body N1 of the nut N is the two-face width dimension s. The diagonal distance between the corners of the main body N1 of the nut N is the diagonal dimension e.

<Lifting mechanism>
The lifting mechanism 2 will be described with reference to FIGS.

Figure 2 shows a perspective view of the entire lifting mechanism 2. Figure 4 shows a perspective view of the outer cylinder 10 of the lifting mechanism 2. Figure 5 shows a perspective view of the shaft 14 and magnet 13 of the lifting mechanism 2. Figure 6 is a cross-sectional view taken along line VI of Figure 4, showing the state in which the surface N1a of the nut N faces the outer surface 11 of the outer cylinder 10 in the lifting mechanism 2. Figure 7 is a view equivalent to Figure 6, showing the state in which the back surface N1b of the nut N faces the outer surface 11 of the outer cylinder 10 in the lifting mechanism 2. Figure 8 shows the posture change guide 19 of the lifting mechanism 2 in a cross-sectional view taken along line VIII of Figure 4. Figure 9 shows the direction change guide 24 of the lifting mechanism in a cross-sectional view taken along line IX of Figure 4.

The up-down direction in Figure 2 is referred to as the up-down direction (indicated by Z). The top in Figure 2 is referred to as the up (indicated by Z1). The bottom in Figure 2 is referred to as the down (indicated by Z2).

The lifting mechanism 2 has an outer cylinder 10, multiple magnets 13 as multiple attraction units, a shaft 14 as part of the rotation drive unit, a motor 15 as part of the rotation drive unit, a regulating guide 16 as a regulating unit, a posture change guide 19 as a posture change unit, a stopper guide 20, a front/back sorting guide 21 as a front/back sorting unit, an overflow prevention guide 22, an upper guide 23, a direction change guide 24 as a direction change unit, a receiving tray 25 as a reservoir unit, and a base 26.

As shown in Figure 4, the outer cylinder 10 extends vertically. Specifically, the outer cylinder 10 extends vertically in a straight line along a vertical axis. The outer cylinder 10 has a cylindrical shape with a central axis O extending vertically. The axial direction of the outer cylinder 10 is the direction in which the central axis O extends, i.e., the vertical direction.

The outer cylinder 10 includes an outer surface 11 and an inner surface 12. The outer surface 11 is the surface of the outer cylinder 10 that is farther away from the central axis O (outer peripheral side). The inner surface 12 is the surface of the outer cylinder 10 that is closer to the central axis O (inner peripheral side). The side that is farther away from the central axis O than the outer cylinder 10 (outer peripheral side) is referred to as the outer surface 11 side. The side that is closer to the central axis O than the outer cylinder 10 (inner peripheral side) is referred to as the inner surface 12 side.

Figure 5 shows the inner surface 12 of the outer tube 10. Multiple magnets 13 are arranged on the inner surface 12 of the outer tube 10. The multiple magnets 13 are arranged in a spiral shape with a central axis O extending vertically (in the axial direction of the outer tube 10) on the inner surface 12 of the outer tube 10 (hereinafter, the spiral formed by the arrangement of the multiple magnets 13 will be referred to as the "spiral C"). In this example, the direction of the spiral C is left-handed (S-winding). In this example, the central axis O of the spiral C and the central axis O of the outer tube 10 are concentric. The multiple magnets 13 apply a magnetic field to the outer surface 11 of the outer tube 10, attracting the nut N to the outer surface 11 of the outer tube 10.

The shaft 14 is housed on the inner surface 12 side of the outer cylinder 10. The shaft 14 is cylindrical with a central axis O extending vertically. A gap is provided between the outer surface 14a of the shaft 14 and the inner surface 12 of the outer cylinder 10. The shaft 14 holds multiple magnets 13 in a spiral arrangement. Specifically, the multiple magnets 13 are fixed to the shaft 14 by, for example, welding or adhesive. Alternatively, grooves may be provided on the outer surface 14a of the shaft 14, and the magnets 13 may be fitted into the grooves.

The magnet 13 is composed of a pair of small magnets 13a, 13b arranged vertically. In the magnet 13, the pair of small magnets 13a, 13b are adjacent to each other with their opposite magnetic poles facing the outer tube 10 (facing the outer periphery). The pair of small magnets 13a, 13b are arranged vertically. The upper small magnet 13a has its north pole facing the outer tube 10. The lower small magnet 13b has its south pole facing the outer tube 10. A strong localized magnetic field is formed at the midpoint 13c of the pair of small magnets 13a, 13b. The nut N is likely to be attracted to the position corresponding to the midpoint 13c on the outer surface 11 of the outer tube 10. Note that the pair of small magnets 13a, 13b with the same magnetic poles facing the outer tube 10 (facing the outer periphery) may also be adjacent to each other.

The rotating shaft of motor 15 is connected to the lower end of shaft 14. Motor 15 rotates shaft 14 around central axis O. The rotation direction of motor 15 (shaft 14) is clockwise when viewed from below (the direction of arrow 15a in Figure 5) (hereinafter simply referred to as clockwise). Motor 15 is, for example, an electric motor.

The shaft 14 and motor 15 rotate the multiple magnets 13 around the central axis O. Specifically, the shaft 14 holds the multiple magnets 13 in a spiral arrangement (with the central axis O extending vertically). The motor 15 rotates the shaft 14 around the central axis O. As a result, the multiple magnets 13 rotate around the central axis O.

As shown in Figure 4, the restricting guide 16 extends vertically (axially). The restricting guide 16 includes a first guide portion 17 and a second guide portion 18. The first guide portion 17 is provided on the outer surface 11 of the outer tube 10 from the vertical middle portion to the lower end. The first guide portion 17 protrudes outward from the outer surface 11 of the outer tube 10 and extends vertically.

Like the first guide portion 17, the second guide portion 18 protrudes radially outward from the outer surface 11 of the outer tube 10 and extends vertically. The second guide portion 18 is located above the first guide portion 17. The second guide portion 18 is positioned slightly offset clockwise relative to the first guide portion 17 in the circumferential direction (rotational direction). Specifically, the lower end of the second guide portion 18 overlaps the upper end of the first guide portion 17. The lower end of the second guide portion 18 is connected to the side surface of the upper end of the first guide portion 17 on the clockwise circumferential side (the right side in Figure 4).

The restricting guide 16 restricts the rotational movement of the nut N, allowing it to move axially upward along the outer surface 11 of the outer cylinder 10. As shown in FIG. 5, the nut N is first attracted to the outer surface 11 of the outer cylinder 10 by the first magnet 13A. As the first magnet 13A rotates clockwise around the central axis O, the nut N attempts to rotate clockwise around the circumferential direction along the outer surface 11 of the outer cylinder 10. However, the restricting guide 16 restricts the nut N from rotating clockwise around the circumferential direction. In other words, even though the first magnet 13A rotates, the nut N does not rotate.

Since the multiple magnets 13 are arranged in a spiral, as the multiple magnets 13 rotate, the second magnet 13B, third magnet 13C, fourth magnet 13D, etc., which are located upstream of the first magnet 13A in the rotational direction (counterclockwise circumferentially), appear one after another axially above the nut N. As a result, the nut N is attracted sequentially to the second magnet 13B, third magnet 13C, fourth magnet 13D, etc., which appear one after another, and moves axially upward along the outer surface 11 of the outer cylinder 10.

As shown in Figure 4, the posture change guide 19 is provided on the lower part of the outer surface 11 of the outer cylinder 10. The posture change guide 19 is composed of a roughly triangular plate-shaped member. As shown in Figure 8, the posture change guide 19 is bent to correspond to the curved shape of the outer surface 11 of the outer cylinder 10. The posture change guide 19 covers a portion of the outer surface 11 of the outer cylinder 10 with a predetermined gap H. The posture change guide 19 is fixed to the side surface on the counterclockwise side (left side in Figures 4 and 8) of the lower part of the first guide section 17 of the restricting guide 16. The gap H between the posture change guide 19 and the outer surface 11 of the outer cylinder 10 is larger than the overall thickness T of the nut N and smaller than the two-face width dimension s.

The position change guide 19 allows a nut N to pass in a lying position (a position in which the front surface N1a or back surface N1b of the weld nut N faces the outer surface 11 of the outer tube 10), but does not allow a nut N to pass in an upright position (a position in which the side surface N1c of the nut N faces the outer surface 11 of the outer tube 10). The position change guide 19 has a first chamfered portion 19a on its end face on the counterclockwise side in the circumferential direction (left side in Figures 4 and 8). The position change guide 19 has a second chamfered portion 19b on its end face on the lower side in the axial direction (lower side in Figure 4, nearer the page in Figure 8).

When the nut N in an upright position attempts to pass through the position change guide 19 from the counterclockwise circumferential side, the nut N is guided by the first chamfered portion 19a of the position change guide 19 and is knocked down. When the nut N in an upright position attempts to pass through the position change guide 19 from below to above in the axial direction, the nut N is guided by the second chamfered portion 19b of the position change guide 19 and is knocked down.

The position change guide 19 changes the position of the nut N from an upright position to a lying position. Once the nut N has been placed in a lying position, it can pass through the position change guide 19.

As shown in Figures 4 and 8, the stopper guide 20 is disk-shaped and is provided around the entire outer surface 11 of the outer cylinder 10. A notch is formed in the first guide portion 17 of the restricting guide 16, and the stopper guide 20 engages with this notch. The stopper guide 20 is located axially above the position change guide 19. The stopper guide 20 is connected to the upper end of the position change guide 19. The stopper guide 20 restricts the nut N from moving upward in the axial direction.

A through-hole 20a is provided in the stopper guide 20 near the engagement portion with the first guide portion 17 of the restriction guide 16, penetrating the stopper guide 20 vertically in the axial direction. The through-hole 20a is provided in the stopper guide 20 at a position facing the guide surface of the first guide portion 17 of the restriction guide 16. The through-hole 20a constitutes an alignment guide (hereinafter referred to as alignment guide 20a). The width dimension of the alignment guide 20a is slightly larger than the diagonal dimension e of the nut N. The alignment guide 20a prevents multiple nuts N in a lying position that have passed through the position conversion guide 19 from passing through, aligning the nuts N vertically in a single row.

The stopper guide 20 restricts the nut N from moving upward in the axial direction at the lower portion of the outer surface 11 of the outer cylinder 10, encouraging it to move in the circumferential clockwise direction. When the nut N comes into contact with the underside of the stopper guide 20, its upward axial movement is restricted and it is guided in the circumferential clockwise direction. Nuts N located counterclockwise from the position change guide 19 are guided into the position change guide 19 by the stopper guide 20. The nut N passes through the position change guide 19 from the counterclockwise side in the circumferential direction.

The nut N continues to move clockwise circumferentially along the stopper guide 20 and comes into contact with the first guide portion 17 of the restriction guide 16. Guided by the first guide portion 17 of the restriction guide 16, the nut N moves axially upward toward the alignment guide 20a. The same applies to the nut N that passes through the posture conversion guide 19 from below in the axial direction.

As shown in FIG. 4, the front/back sorting guide 21 is L-shaped. The front/back sorting guide 21 includes an attachment portion 21a and a protrusion 21b. In the front/back sorting guide 21, the attachment portion 21a and the protrusion 21b are perpendicular to each other. The attachment portion 21a of the front/back sorting guide 21 extends vertically along the axial direction of the outer tube 10. The protrusion 21b of the front/back sorting guide 21 extends perpendicularly inward toward the outer surface 11 of the outer tube 10. The second guide portion 18 of the regulating guide 16 is provided with a fixing portion 18a that protrudes outward. The attachment portion 21a of the front/back sorting guide 21 is attached to the fixing portion 18a of the second guide portion 18 of the regulating guide 16.

As shown in Figures 6 and 7, the gap L between the protrusion 21b of the front and back sorting guide 21 and the outer surface 11 of the outer cylinder 10 is smaller than the overall thickness T of the nut N and larger than the thickness t of only the main body N1 of the nut N.

The front and back sorting guide 21 sorts the front and back of the nut N (which moves axially upward while being guided by the second guide portion 18 of the regulating guide 16) based on the difference in the protruding thickness (total thickness T and thickness t) from the outer surface 11 of the outer tube 10.

As shown in Figure 6, when the nut N is oriented with its surface N1a facing the outer surface 11 of the outer cylinder 10, it does not come into contact with the protrusion 21b of the front/back sorting guide 21 and passes through the front/back sorting guide 21. At this time, the nut N passes through the front/back sorting guide 21 at approximately the center position between the radially adjacent protrusions N3, N3.

As shown in Figure 7, when the back surface N1b (on which the protrusion N3 is provided) of the nut N faces the outer surface 11 of the outer cylinder 10, the nut N is struck by the protrusion 21b of the front/back sorting guide 21 and prevented from passing through the front/back sorting guide 21. The nut N struck by the front/back sorting guide 21 falls axially downward into the receiving tray 25, which will be described later.

In summary, the front/back sorting guide 21 allows the nut N to pass when the front surface N1a faces the outer surface 11 of the outer cylinder 10, based on the difference in the protruding thickness (total thickness T and thickness t) from the outer surface 11 of the outer cylinder 10, but repels the nut N and prevents it from passing when the back surface N1b (on which the protrusion N3 is provided) faces the outer surface 11 of the outer cylinder 10.

As shown in Figure 4, the extrusion prevention guide 22 is provided on the outer surface 11 of the outer tube 10, near the front/back sorting guide 21. The extrusion prevention guide 22 extends up and down in the axial direction and is arranged on the counterclockwise circumferential side so as to face the second guide portion 18 of the restricting guide 16. The extrusion prevention guide 22 prevents the nut N, which has passed or is about to pass through the front/back sorting guide 21 while being guided by the second guide portion 18 of the restricting guide 16, from extruding in the counterclockwise circumferential direction. The distance between the extrusion prevention guide 22 and the second guide portion 18 of the restricting guide 16 is slightly larger than the two-face width dimension s of the nut N. A gap is provided between the lower end of the extrusion prevention guide 22 and the upper end of the first guide portion 17 of the restricting guide 16.

As shown in Figures 4 and 9, the upper guide 23 is located on the outer surface 11 of the outer cylinder 10, axially above the front/back sorting guide 21. The upper guide 23 is composed of a channel member with a groove-shaped cross section. The upper guide 23 extends up and down in the axial direction.

The upper guide 23 includes a groove bottom wall 23a and groove side walls 23b. The groove side walls 23b extend inward from both widthwise ends of the groove bottom wall 23a. The upper guide 23 covers the outer surface 11 of the outer cylinder 10 so that the inner surface of the groove bottom wall 23a faces the outer surface 11 of the outer cylinder 10.

The space surrounded by the upper guide 23 and the outer surface 11 of the outer cylinder 10 forms a passageway for the nut N, which has passed through the front/back sorting guide 21, to move axially upward. The distance between the groove side walls 23b of the upper guide 23 is greater than the two-face width dimension s of the nut N. The distance between the inner surface of the groove bottom wall 23a of the upper guide 23 and the outer surface 11 of the outer cylinder 10 is greater than the overall thickness T of the nut N. The nut N passes through the upper guide 23 and moves further axially upward.

As shown in Figures 4 and 9, the direction change guide 24 is located at an upper position G1 on the upper part of the lifting mechanism 2. The direction change guide 24 (upper position G1) is located on the outer surface 11 of the outer cylinder 10, above the upper end of the upper guide 23. The direction change guide 24 (upper position G1) is located near the upper end of the outer cylinder 10. The direction change guide 24 is composed of a tubular member with a square cross section. The direction change guide 24 is made of metal.

The direction change guide 24 extends downward as it approaches the outer periphery. The base end of the direction change guide 24 is connected to the outer surface 11 of the outer tube 10 above the upper end of the upper guide 23. The tip end of the direction change guide 24 is located on the outer periphery and below the base end of the direction change guide 24.

The distance between the two side walls 24a of the direction change guide 24 (facing each other circumferentially around the outer tube 10) is greater than the two-face width dimension s of the nut N. The distance between the upper wall 24b and lower wall 24c of the direction change guide 24 (facing each other diagonally above and below) is greater than the overall thickness T of the nut N.

An inlet 24d formed by a notch is formed in the base end (closer to the outer surface 11 of the outer cylinder 10) of the lower wall 24c of the direction change guide 24. The inlet 24d of the direction change guide 24 faces the outer surface 11 of the outer cylinder 10. The width of the inlet 24d (in the direction perpendicular to the plane of the paper in Figure 9) is greater than the two-face width dimension s of the nut N. The depth of the inlet 24d (in the diagonal up-down, left-right directions in Figure 9) is greater than the overall thickness T of the nut N. A gap may be formed between the upper end of the upper guide 23 and the inlet 24d of the direction change guide 24. A chute 3 is connected to the tip of the direction change guide 24. The chute 3 will be described later.

The direction change guide 24 changes the direction of the nut N, which moves upward along the outer surface 11 of the outer cylinder 10, downward at the upper position G1. Specifically, the nut N, which moves upward along the outer surface 11 of the outer cylinder 10 while being guided by the upper guide 23 (with its surface N1a facing the outer surface 11 of the outer cylinder 10), is introduced into the inlet 24d of the direction change guide 24 at the upper position G1 and then comes into contact with the upper wall 24b of the direction change guide 24, thereby changing its direction radially outward and downward. The surface N1a of the nut N faces the lower wall 24c of the direction change guide 24. The protrusion N3 on the back surface N1b of the nut N faces the upper wall 24b of the direction change guide 24. The nut N moves radially outward and downward in the direction change guide 24 due to gravity.

As shown in Figure 2, the tray 25 is located at the lower position G2 in the lifting mechanism 2. The lower position G2 is lower than the upper position G1. In other words, the upper position G1 is higher than the lower position G2. The tray 25 (lower position G2) is located below the position change guide 19 on the outer surface 11 of the outer cylinder 10. The tray 25 is deep and open at the top. The tray 25 is located so that it extends toward the outer surface 11 of the outer cylinder 10. In detail, the outer cylinder 10 passes through the center of the tray 25 from top to bottom.

The tray 25 stores multiple nuts N at the lower position G2. The multiple nuts N are stored in the tray 25 (more specifically, in the area between the tray 25 and the outer surface 11 of the outer cylinder 10) in a misaligned state at the lower position G2. The nuts N stored in the tray 25 are adsorbed to the outer surface 11 of the outer cylinder 10.

The base 26 is plate-shaped and is located at the bottom of the lifting mechanism 2. The base 26 is placed on a foundation. The motor 15 is placed on the top surface of the base 26. The outer cylinder 10 is placed on top of the motor 15.

To summarize the lifting mechanism 2, the lifting mechanism 2 lifts the nut N from the tray 25 at the lower position G2 to the direction change guide 24 at the upper position G1.

<Shooter>
The chute 3 will now be described with reference to FIGS.

Figure 1 shows a schematic diagram of the chute 3. Figure 9 shows a cross-sectional view of the chute 3 taken along line IX of Figure 4. Figure 10 shows a cross-sectional view of the chute 3 taken along line X of Figure 9.

The chute 3 has a cylindrical member 31 and a long plate member 32. The cylindrical member 31 is cylindrical. The cross section of the cylindrical member 31 is rectangular. The cylindrical member 31 is a tube. The cylindrical member 31 is made of resin. The cylindrical member 31 is also called a hose. The cylindrical member 31 is made of a flexible material.

The cylindrical member 31 is made of, for example, urethane, elastomer, olefin, nylon, fluororesin, polyurethane, polypropylene, vinyl chloride, or synthetic rubber. The cylindrical member 31 extends in the longitudinal direction.

The long plate member 32 is arranged inside the cylindrical member 31. The long plate member 32 is plate-shaped. The long plate member 32 is made of metal. The long plate member 32 extends along the length of the cylindrical member 31. The long plate member 32 extends from one end to the other end of the cylindrical member 31.

The length direction of the elongated plate member 32 coincides with the length direction of the cylindrical member 31. The width direction of the elongated plate member 32 roughly coincides with the inner diameter of the cylindrical member 31. The elongated plate member 32 fits into the inner groove 31c provided on the inner surface of the cylindrical member 31.

The cylindrical member 31 includes a first inner surface 31a and a second inner surface 31b that face each other. The back surface 32a on one side in the thickness direction of the elongated plate member 32 is positioned so as to face the first inner surface 31a of the cylindrical member 31. A gap is formed between the surface 32b on the other side in the thickness direction of the elongated plate member 32 and the second inner surface 31b of the cylindrical member 31.

The long plate member 32 is made of a material that is harder than the material that makes up the tubular member 31. The long plate member 32 is made of a material that is elastically deformable. For example, carbon steel, stainless steel, aluminum, copper, etc. can be used for the long plate member 32. It is preferable to use SUS301 CSP3/4H for the long plate member 32.

The nut N passes through the interior of the cylindrical member 31. The surface N1a of the nut N faces the second inner surface 31b of the cylindrical member 31. The back surface N1b of the nut N faces the first inner surface 31a of the cylindrical member 31 via the elongated plate member 32. The nut N slides on the surface 32b of the elongated plate member 32. Specifically, the protrusion N3 of the nut N slides on the surface 32b of the elongated plate member 32. The screw hole N2 of the nut N is perpendicular to the transport direction of the nut N passing through the cylindrical member 31 (the longitudinal direction of the cylindrical member 31).

The chute 3 (tubular member 31 and long plate member 32) extends downward from the direction change guide 24 (upper position G1) of the lifting mechanism 2 to the supply mechanism 4. As it extends downward from the direction change guide 24 (upper position G1) of the lifting mechanism 2 to the supply mechanism 4, the chute 3 may snake back and forth or left and right, rotate in a spiral, or twist.

The chute 3 does not return upward (does not snake upward) while extending downward from the direction change guide 24 (upper position G1) of the lifting mechanism 2 to the supply mechanism 4. The chute 3 extends downward from the direction change guide 24 (upper position G1) of the lifting mechanism 2 to the supply mechanism 4 without returning upward. The downstream end of the chute 3 is connected via the connecting pipe 5 to the nut receiving chamber 66 of the nut receiver 60 in the supply mechanism 4.

The chute 3 drops the nuts N sent from the direction change guide 24 (upper position G1) of the lifting mechanism 2 downward to the supply mechanism 4 without returning them upward.

<Supply mechanism>
(Configuration of supply mechanism)
The configuration of the supply mechanism 4 will be described with reference to FIGS.

In the following description, the left-right direction in FIG. 11 is the front-to-back direction (indicated by X), the up-down direction in FIG. 11 is the up-down direction (indicated by Z), and the direction perpendicular to the plane of the paper in FIG. 11 is the left-to-right direction (indicated by Y). The left in FIG. 11 is the front (indicated by X1), and the right in FIG. 11 is the rear (indicated by X2). The top in FIG. 11 is the top (indicated by Z1), and the bottom in FIG. 11 is the bottom (indicated by Z2). The front of the plane of the paper in FIG. 11 is the left, and the back of the plane of the paper in FIG. 11 is the right. As shown in FIG. 1, in reality, the front-to-back and left-to-right directions are inclined relative to the horizontal plane, going from rear to front and from top to bottom.

Figures 11 to 14 show front views (partial cross-section) of the supply mechanism 4 as seen from the left. Details will be described later, but Figures 11 to 14 show different states of the supply mechanism 4. The supply mechanism 4 supplies a nut N to a target position J (between the lower electrode 104 and upper electrode 109 of the resistance welding machine 100; see also Figure 1).

As shown in FIG. 11, the supply mechanism 4 includes a rod 40, a piston 50, a cylinder 51, a lid 52, an actuator 53, a nut holder 60 as a part holder, a check valve 70, a sealing mechanism 80, and a connecting member 90.

Figure 16 shows a plan view of the rod 40 as seen from above. As shown in Figure 16, the rod 40 is formed in a rod shape. The axial direction of the axis of the rod 40 extends from front to back. The rod 40 includes a front end portion 41 and a rear portion 42.

The front end 41 constitutes the front end of the rod 40 and the portion slightly rearward from the front end. In the rod 40, the rear portion 42 continues rearward from the front end 41. The rear portion 42 extends rearward from the front end 41. The rear portion 42 constitutes the rear portion of the rod 40 other than the front end 41. The outer diameter of the front end 41 is smaller than the outer diameter of the rear portion 42. Conversely, the outer diameter of the rear portion 42 is larger than the outer diameter of the front end 41.

A stepped surface 43 is formed between the front end 41 and rear end 42 of the rod 40. The stepped surface 43 faces forward. The outer diameter of the front end 41 is smaller than the inner diameter of the screw hole N2 of the nut N. The outer diameter of the rear end 42 is larger than the inner diameter of the screw hole N2 of the nut N.

The rod 40 includes an air outlet 44 as a gas outlet, an air inlet 45 as a gas inlet, and an air passage 46 as a gas passage.

The air outlet 44 is provided on the outer periphery 47 of the front end 41 of the rod 40. There may be multiple air outlets 44. The air outlets 44 face outward and rearward, i.e., diagonally rearward. It is preferable that the air outlets 44 face upward and rearward. The air outlets 44 face the stepped surface 43.

The air inlet 45 is provided on the outer periphery 47 of the rod 40, rearward of the air outlet 44. The air inlet 45 is located rearward of the air outlet 44. The air inlet 45 is provided on the outer periphery 47 at the rear end of the rear portion 42 of the rod 40. The air inlet 45 faces the outer periphery. In this example, the air inlet 45 faces upward.

The air passage 46 is provided in the interior 40a of the rod 40. The air passage 46 extends in the front-to-rear direction within the interior 40a of the rod 40. The air passage 46 extends in the front-to-rear direction within the interior 40a of the front end 41 and rear end 42 of the rod 40. The air passage 46 connects the air outlet 44 and the air inlet 45 to each other.

As the rod 40 advances axially (longitudinal), the front end 41 of the rod 40 is inserted into the threaded hole N2 of the nut N. This causes the nut N to be hung on the front end 41 of the rod 40. As the rod 40 advances further, the nut N hung on the front end 41 of the rod 40 is supplied to the destination position J. In summary, the rod 40 supplies the nut N having the threaded hole N2 to the destination position J by advancing.

As shown in Figure 11, the piston 50 is connected to the rear end (rear portion 42) of the rod 40 via a connecting member 90 (described below). The piston 50 is formed in a roughly disk shape. The axis of the piston 50 extends forward and backward. The piston 50 is concentric with the rod 40. The rod 40 extends forward from the piston 50. The rod 40 and piston 50 move forward and backward together. The outer diameter of the piston 50 is equal to the inner diameter of the cylinder 51.

The connecting member 90 is also referred to as a joint. The connecting member 90 is formed in a generally cylindrical shape. The outer diameter of the connecting member 90 is smaller than the outer diameter of the piston 50 (the inner diameter of the cylinder 51). The outer diameter of the connecting member 90 is slightly larger than the outer diameter of the rod 40 (the rear portion 42). The connecting member 90 is positioned between the rod 40 and the piston 50, i.e., behind the rod 40 and in front of the piston 50. The connecting member 90 connects the rod 40 and the piston 50 to each other. The connecting member 90 moves back and forth integrally with the rod 40 and the piston 50.

The cylinder 51 is approximately cylindrical. The axis of the cylinder 51 extends from front to back. The cylinder 51 houses the rod 40 and piston 50 inside. The cylinder 51 is concentric with the rod 40 and piston 50. The front end of the cylinder 51 is open. The rear end of the cylinder 51 is open.

The lid 52 includes a main body portion 52a and a fitting portion 52b. The main body portion 52a forms the front portion of the lid 52. The main body portion 52a is generally cylindrical. The fitting portion 52b forms the rear portion of the lid 52. The fitting portion 52b is also generally cylindrical. The outer diameter of the fitting portion 52b is smaller than the outer diameter of the main body portion 52a. The fitting portion 52b protrudes rearward from the rear end surface of the main body portion 52a. In the lid 52, the main body portion 52a and the fitting portion 52b are concentric with each other.

The outer diameter of the main body 52a of the lid 52 is equal to the outer diameter of the cylinder 51. The outer diameter of the fitting portion 52b of the lid 52 is equal to the inner diameter of the cylinder 51. The fitting portion 52b of the lid 52 is fitted into the inner diameter of the front end of the cylinder 51. The fitting portion 52b of the lid 52 is fitted into the interior of the front end of the cylinder 51 through the front end opening of the cylinder 51. A male thread is formed on the outer peripheral surface of the fitting portion 52b of the lid 52. A female thread is formed on the inner peripheral surface of the front end of the cylinder 51.

The rear end surface of the main body 52a of the lid 52 contacts the front end surface of the cylinder 51. The fitting portion 52b of the lid 52 forms a wall that covers the front end opening of the cylinder 51. The fitting portion 52b of the lid 52 closes the front end of the cylinder 51.

The lid 52 is concentric with the rod 40, piston 50, and cylinder 51. The lid 52 is positioned forward of the piston 50. The lid 52 closes the cylinder 51 forward of the piston 50.

A hole 52c is provided in the center of the lid 52. The hole 52c is positioned at the axis of the lid 52. The hole 52c penetrates the lid 52 from front to back (across the main body portion 52a and the fitting portion 52b). The diameter of the hole 52c is slightly larger than the rear portion 42 of the rod 40. The rod 40, which extends forward from the piston 50, penetrates the hole 52c in the lid 52 from front to back. The space between the lid 52 and the rod 40 is sealed to prevent air A from leaking from the air chamber R in the cylinder 51 through the hole 52c into the external space E outside the cylinder 51.

The actuator 53 is a known electric actuator. The actuator 53 is driven electrically. The actuator 53 is composed of, for example, an electromagnetic solenoid, a ball screw mechanism, a linear motor, a servo motor, a stepping motor, or a rack gear motor. The actuator 53 includes an electric mechanism 53a and a drive rod 53b.

The electric mechanism 53a has a cylindrical housing. The axis of the electric mechanism 53a (housing) extends forward and backward. The electric mechanism 53a is connected to the rear end of the cylinder 51. In other words, the electric mechanism 53a covers the rear end opening of the cylinder 51. The electric mechanism 53a is connected to an external power source.

The drive rod 53b extends forward and backward. The drive rod 53b protrudes forward from the front end surface of the housing of the electric mechanism 53a. The drive rod 53b is housed inside the cylinder 51. The drive rod 53b is inserted into the cylinder 51 through the rear end opening of the cylinder 51. The drive rod 53b is moved forward and backward by the electrical action of the electric mechanism 53a.

The front end of the drive rod 53b is connected to the rear surface of the piston 50. The actuator 53 moves the piston 50 and the rod 40 (connected to the piston 50) back and forth by the electric mechanism 53a moving the drive rod 53b back and forth.

Figure 15 shows a perspective view of the nut receiver 60. As shown in Figures 11 and 15, the nut receiver 60 includes a holder 61, a receiving portion 62, and a door 63. Note that the door 63 is not shown in Figure 15. The nut receiver 60 is positioned forward of the lid 52 and the cylinder 51.

As shown in FIG. 11, the holder 61 is formed in a cylindrical shape. The holder 61 is concentric with the lid 52 and the cylinder 51. As shown in FIG. 11, the holder 61 includes a main body portion 61a and a fitting portion 61b. The main body portion 61a constitutes the portion of the holder 61 other than the rear end portion. The fitting portion 61b constitutes the rear end portion of the holder 61. The outer diameter of the fitting portion 61b is smaller than the outer diameter of the main body portion 61a.

The outer diameter of the body 61a of the holder 61 is equal to the outer diameter of the body 52a of the lid 52. The outer diameter of the fitting portion 61b of the holder 61 is equal to the inner diameter of the front end of the body 52a of the lid 52. The fitting portion 61b of the holder 61 is fitted into the inner diameter of the front end of the body 52a of the lid 52. A male thread is formed on the outer peripheral surface of the fitting portion 61b of the holder 61. A female thread is formed on the inner peripheral surface of the front end of the body 52a of the lid 52.

As shown in FIG. 15, the receiving portion 62 includes a rear wall 62a and two left and right side walls 62b. The rear wall 62a is plate-shaped with thickness in the front-to-rear direction and extends up and down and left and right. The left and right side walls 62b are plate-shaped with thickness in the left and right directions and extend up and down and front and back. The left and right side walls 62b protrude forward from both the left and right ends of the rear wall 62a.

A rod-through hole 64 is provided in the rear wall 62a. The rod-through hole 64 penetrates the rear wall 62a from front to rear. The inner diameter of the rod-through hole 64 is larger than the outer diameter of the rod 40 (the rear portion 42 thereof). The rod-through hole 64 is concentric with the rod 40. The rod 40 passes through the rod-through hole 64 when moving forward and backward.

In the nut receiver 60, the lower portion of the inner surface of the left and right side walls 62b protrudes inward more than the upper portion, forming a step-shaped stopper 65. In the nut receiver 60, a nut receiving chamber 66 serving as a parts receiving chamber is formed in the space surrounded by the inner surface of the rear wall 62a and the inner surfaces of the left and right side walls 62b.

Above the nut receiver 60, the chute 3 is connected via a connecting pipe 5. Nuts N sent from the direction change guide 24 (upper position G1) of the lifting mechanism 2 are introduced into the upstream end of the chute 3 with their protrusions N3 aligned so that they face the specified direction.

The downstream end of the chute 3 is connected to the nut receiving chamber 66 of the nut receiver 60 via the connecting pipe 5. The connecting pipe 5 is formed in a cylindrical shape with a square cross section. The connecting pipe 5 extends vertically. The lower end of the connecting pipe 5 is connected to the upper end of the rear wall 62a of the receiver 62 and the upper ends of the left and right side walls 62b. The downstream end of the chute 3 fits into the inner diameter of the upper end of the connecting pipe 5.

The connecting pipe 5 includes a groove-shaped groove portion 5a that opens forward, and a lid portion 5b that covers the front opening of the groove portion 5a. The lid portion 5b of the connecting pipe 5 is located forward of the front ends of the left and right side walls 62b of the receiving portion 62.

The nut receiver 60 receives the nut N sent from the chute 3 through the connecting pipe 5 into the nut receiving chamber 66, with the protrusion N3 facing forward, using the stopper 65. The screw hole N2 of the nut N received by the stopper 65 is concentric with the rod through-hole 64 (and therefore the rod 40). The stopper 65 receives the nut N that has dropped into the nut receiving chamber 66 from the chute 3 (through the connecting pipe 5).

A discharge hole 67 is provided below the stopper 65 (between the lower portions of the left and right side walls 62b). The discharge hole 67 is provided to discharge a nut N that is smaller (has a smaller diameter) than a standard nut N to the outside if it is mistakenly sent into the nut receiving chamber 66.

As shown in Figure 11, in the nut receiver 60, the door 63 is positioned in front of the nut receiving chamber 66. The door 63 is plate-shaped with thickness in the front and rear directions, and extends up and down and left and right. The door 63 covers the nut receiving chamber 66 from the front. Both left and right ends of the lower end of the door 63 are attached to the lower ends of the left and right side walls 62b by hinges (not shown). A spring (not shown) is provided in the hinge. The spring urges the door 63 rearward (in the closing direction). The spring may be, for example, a coil spring or a leaf spring.

When no forward pressure is applied to the door 63, the restoring force of the spring causes the door 63 to close backward. When a forward pressure is applied to the door 63, the door 63 opens forward against the rearward restoring force of the spring (in the closing direction).

As shown in Figure 11, the piston 50, cylinder 51, and lid 52 define an air chamber R as a gas chamber. Air A is stored in the air chamber R as a gas. When the piston 50 moves forward, the volume of the air chamber R decreases, and the air A in the air chamber R is compressed. When the piston 50 moves backward, the volume of the air chamber R increases, and the air A in the air chamber R expands.

The air inlet 45 of the rod 40 faces the air chamber R. The air inlet 45 is located within the air chamber R. Air A is introduced from the air chamber R into the air inlet 45.

The air passage 46 of the rod 40 extends forward and backward through the interior 40a of the rod 40 and connects the air outlet 44 and the air inlet 45 to each other. Air A passes through the air passage 46 from the air inlet 45 to the air outlet 44.

As shown in Figure 16, the air outlet 44 of the rod 40 does not face the air chamber R. The air outlet 44 is located outside the air chamber R. The air outlet 44 is located forward of the lid 52. The air outlet 44 is provided on the outer periphery 47 of the front end 41 of the rod 40. The air outlet 44 faces the outer periphery and rearward, i.e., diagonally rearward. The air outlet 44 faces the step surface 43 between the front end 41 and rear portion 42 of the rod 40.

The longitudinal length of the front end 41 of the rod 40 is greater than the thickness t of the main body N1 of the nut N. Specifically, the longitudinal distance from the air outlet 44 to the step surface 43 at the front end 41 of the rod 40 is greater than the thickness t of the main body N1 of the nut N.

Air A is blown out from the air outlet 44. Air A is blown out from the air outlet 44 toward the outer periphery and rearward, i.e., diagonally rearward. Air A is blown out from the air outlet 44 toward the step surface 43 between the front end 41 and rear end 42 of the rod 40.

As will be described in more detail below, air A blown out from the air outlet 44 at the front end 41 of the rod 40 presses the nut N (hanging on the front end 41 of the rod 40) against the step surface 43 between the front end 41 and rear portion 42 of the rod 40.

Returning to Figure 11, the check valve 70 is also called a check valve. As described above, the piston 50, cylinder 51, and lid 52 define the air chamber R. The air chamber R is disposed within the cylinder 51. A communication passage (not shown) is provided in the cylindrical wall of the cylinder 51, connecting the air chamber R within the cylinder 51 with the external space E outside the cylinder 51. The check valve 70 controls the flow of air A between the air chamber R within the cylinder 51 and the external space E outside the cylinder 51 (communication passage).

The check valve 70 allows air A to flow from the external space E outside the cylinder 51 into the air chamber R inside the cylinder 51, while restricting the outflow of air A from the air chamber R inside the cylinder 51 to the external space E outside the cylinder 51. Air A can flow from the external space E into the air chamber R through the check valve 70. Air A cannot flow from the air chamber R to the external space E through the check valve 70.

As shown in FIG. 11, the sealing mechanism 80 is provided on the rod 40. The sealing mechanism 80 includes a bushing 81 and a coil spring 82 as a biasing member. The sealing mechanism 80 is disposed in the air chamber R.

Figure 17 shows a side view of the sealing mechanism 80. Figure 18 shows a front view (partial cross section) of the sealing mechanism 80. The bushing 81 is made of rubber. As shown in Figures 11, 17, and 18, the bushing 81 is formed in a cylindrical shape. The axis of the bushing 81 extends in the front-to-rear direction. The bushing 81 is hung on the rod 40. More specifically, the bushing 81 is hung on the outer periphery 47 of the rear portion 42 of the rod 40. The bushing 81 is concentric with the rod 40.

The bushing 81 is disposed within the cylinder 51. The bushing 81 is disposed forward of the piston 50. The bushing 81 is disposed rearward of the lid 52. The bushing 81 is disposed in the air chamber R.

The bushing 81 is fitted onto the rod 40 (at its rear portion 42). The inner diameter of the bushing 81 is in a fitting relationship with the outer diameter of the rod 40 (at its rear portion 42). The inner diameter of the bushing 81 is slightly smaller, approximately equal to, or slightly larger than the outer diameter of the rod 40 (at its rear portion 42). The outer diameter of the bushing 81 is smaller than the inner diameter of the cylinder 51.

When no forward or backward pressing force is acting on the bushing 81, the bushing 81 moves forward or backward together with the rod 40. When forward or backward pressing force is acting on the bushing 81, the bushing 81 can move forward or backward relative to the rod 40.

The coil spring 82 is coil-shaped. The outer shape of the coil spring 82 is cylindrical. The coil spring 82 is wound around the rod 40. Specifically, the coil spring 82 is wound around the outer periphery 47 of the rear portion 42 of the rod 40. The coil spring 82 extends in the front-to-rear direction. The coil spring 82 is concentric with the rod 40. The diameter of the coil spring 82 is larger than the inner diameter of the bushing 81 and smaller than the outer diameter of the bushing 81.

The coil spring 82 is positioned rearward of the bushing 81. The coil spring 82 is wound around the rod 40 rearward of the bushing 81.

The coil spring 82 is positioned forward of the connecting member 90 (positioned forward of the piston 50). The coil spring 82 is wound around the rod 40 forward of the piston 50. More specifically, the coil spring 82 is wound around the rod 40 forward of the connecting member 90 (positioned forward of the piston 50).

The front end of the coil spring 82 is connected to the rear end surface of the bushing 81. The rear end of the coil spring 82 is connected to the front end surface of the connecting member 90. The coil spring 82 connects the bushing 81 and the connecting member 90 in the front-rear direction.

The coil spring 82 holds the bushing 81 to the rod 40 (rear portion 42) via the connecting member 90. When the coil spring 82 is at its natural length, the front end of the coil spring 82 is located forward of the air inlet 45. In other words, when the coil spring 82 is at its natural length, the bushing 81 is located forward of the air inlet 45. At this time, the air inlet 45 is open.

The coil spring 82 exerts a restoring force F as a biasing force on the bushing 81 in the forward direction (see Figure 18). The coil spring 82 biases the bushing 81 forward, moving it away from the air inlet 45. When the coil spring 82 is at its natural length, the forward restoring force F is zero.

The bushing 81 comes into contact with the lid 52 as it follows the forward movement of the rod 40. After contacting the lid 52, the bushing 81 moves rearward relative to the rod 40 against the forward restoring force F from the coil spring 82 to the bushing 81 due to the rearward pressing force P from the lid 52 on the bushing 81, thereby closing the air inlet 45.

As the rod 40 advances, it supplies the nut N to the target position J, and at the same time, the bushing 81 closes the air inlet 45.

To simultaneously achieve the operation of supplying the nut N to the target position J and the operation of the bushing 81 closing the air inlet 45, the longitudinal dimension of the rod 40, the position of the air inlet 45 on the rod 40, the longitudinal dimension of the bushing 81, the longitudinal dimension of the coil spring 82, the positional relationship between the bushing 81 and the air inlet 45 when the coil spring 82 is at its natural length, the spring constant of the coil spring 82, etc. are appropriately set.

The supply mechanism 4 receives the nut N that has fallen from the chute 3 (via the connecting pipe 5) into the nut receiving chamber 66 with the stopper 65, and supplies the nut N received by the stopper 65 to the target position J by advancing the rod 40.

(Supply of nuts by supply mechanism)
The supply of nuts N by the supply mechanism 4 will be described mainly with reference to Figures 11 to 14. Figure 11 shows a front view (partially in cross section) of the supply mechanism 4 before the rod 40 is inserted into the screw hole N2 of the nut N. Figure 12 shows a front view (partially in cross section) of the supply mechanism 4 after the rod 40 has been inserted into the screw hole N2 of the nut N. Figure 13 shows a front view (partially in cross section) of the supply mechanism 4 at the moment when the rod 40 supplies the nut N to the target position J. Figure 14 shows a front view (partially in cross section) of the supply mechanism 4 after the rod 40 has retracted from the target position J.

Figure 11 shows the state before the front end 41 of the rod 40 is inserted into the threaded hole N2 of the nut N. At this time, the actuator 53 retracts the drive rod 53b to its fullest extent rearward due to the electrical action of the electric mechanism 53a. The piston 50, connecting member 90, and rod 40 are all retracted to their fullest extent rearward.

The front end 41 of the rod 40 is positioned within the holder 61 of the nut receiver 60. The front end 41 of the rod 40 is positioned rearward of the nut receiving chamber 66 of the receiving portion 62 of the nut receiver 60. More specifically, the front end 41 of the rod 40 is positioned rearward of the rod insertion hole 64 in the rear wall 62a of the receiving portion 62 of the nut receiver 60.

The nut N sent from the chute 3 to the nut receiving chamber 66 via the connecting pipe 5 is caught (received) on the stopper 65 of the nut receiver 60. The nut N is placed in the nut receiving chamber 66 with the protrusion N3 facing forward and caught on the stopper 65. In this way, in the supply mechanism 4, the stopper 65 receives the nut N that has fallen into the nut receiving chamber 66 from the chute 3 (via the connecting pipe 5).

The door 63 closes to the rear due to the restoring force of the spring attached to the hinge, covering the nut receiving chamber 66 from the front.

The volume of the air chamber R, defined by the piston 50, cylinder 51, and lid 52, is at its maximum. Air chamber R is filled with air A. The air A in air chamber R is fully expanded. The air inlet 45 (at the rear portion 42) of the rod 40 faces the air chamber R (is located within the air chamber R). Air A still remains in the air chamber R and has not yet been introduced into the air inlet 45.

As described above, the sealing mechanism 80 is provided on the rod 40 in the air chamber R. The sealing mechanism 80 includes a bushing 81 and a coil spring 82. The coil spring 82 is at its natural length. The bushing 81 (connected to the front end of the coil spring 82) is located forward of the air inlet 45 of the rod 40. The coil spring 82 urges the bushing 81 forward with a restoring force F, moving it away from the air inlet 45. However, because the coil spring 82 is at its natural length, the forward restoring force F from the coil spring 82 to the bushing 81 is zero. The bushing 81 is fitted into the rod 40. The bushing 81 also moves forward in response to the forward movement of the rod 40.

Figure 12 shows the state after the front end 41 of the rod 40 has been inserted into the threaded hole N2 of the nut N. At this time, the actuator 53 pushes the drive rod 53b forward due to the electrical action of the electric mechanism 53a. The piston 50, connecting member 90, and rod 40 move forward.

The front end 41 of the rod 40 is positioned in the nut receiving chamber 66 of the nut receiver 60. The front end 41 of the rod 40 enters the nut receiving chamber 66 through the rod through-hole 64 in the rear wall 62a. The front end 41 of the rod 40 is inserted into the threaded hole N2 of the nut N (which is hooked (received) by the stopper 65 in the nut receiving chamber 66). The nut N is hung on the front end 41 of the rod 40.

When the rod 40 moves forward, the step surface 43 between the front end 41 and rear end 42 of the rod 40 comes into contact with the rear end surface of the nut N. The air outlet 44 on the outer periphery 47 of the front end 41 of the rod 40 is located forward of the front end surface of the nut N.

With the nut N engaged, the front end 41 of the rod 40 pushes the door 63 forward. The front end 41 of the rod 40 applies a forward pressing force to the door 63, causing the door 63 to open forward against the spring's restoring force (in the closing direction).

A portion of the rear section 42 of the rod 40 is located forward of the rod through-hole 64 and is positioned in the nut receiving chamber 66. The next nut N to be sent from the chute 3 to the nut receiving chamber 66 via the connecting pipe 5 is placed on the upper part of the rear section 42 of the rod 40, which is positioned in the nut receiving chamber 66.

As the piston 50 advances, the volume of the air chamber R decreases. The air A in the air chamber R is compressed. The compressed air A is introduced from the air chamber R into the air inlet 45 on the outer periphery 47 of the rear portion 42 of the rod 40.

Air A introduced into the air inlet 45 travels from rear to front through the air passage 46 inside the rod 40 (40a) and is blown out from the air outlet 44. Specifically, air A is blown out from the air outlet 44 toward the outer periphery and rearward, i.e., diagonally rearward. More specifically, air A is blown out from the air outlet 44 toward the step surface 43 between the front end 41 and rear end 42 of the rod 40. As mentioned above, the air outlet 44 is located forward of the front end face of the nut N.

Air A blown out from the air outlet 44 at the front end 41 of the rod 40 presses the nut N (hanging on the front end 41 of the rod 40) against the step surface 43 between the front end 41 and rear end 42 of the rod 40. This firmly holds the nut N to the front end 41 of the rod 40.

The nut N attached to the front end 41 of the rod 40 has not yet been supplied (reached) to the target position J.

A communication passage (not shown) is provided in the cylindrical wall of the cylinder 51, connecting the air chamber R inside the cylinder 51 with the external space E outside the cylinder 51. The check valve 70 controls the flow of air A between the air chamber R inside the cylinder 51 and the external space E outside the cylinder 51 (communication passage).

The check valve 70 regulates (blocks or inhibits) the outflow of air A from the air chamber R inside the cylinder 51 to the external space E outside the cylinder 51. Air A compressed in the air chamber R does not flow through the check valve 70 into the external space E outside the cylinder 51.

The coil spring 82 is still at its natural length. The forward restoring force F from the coil spring 82 to the bushing 81 is still zero. The bushing 81 is positioned forward of the air inlet 45. The bushing 81 also moves forward in response to the forward movement of the rod 40.

Figure 13 shows the state at the moment when the rod 40 supplies the nut N to the destination position J. Figure 18 shows the sealing mechanism 80 at the moment when the rod 40 supplies the nut N to the destination position J. The actuator 53 pushes the drive rod 53b further forward due to the electrical action of the electric mechanism 53a. The piston 50, connecting member 90, and rod 40 move further forward.

The nut N hung on the front end 41 of the rod 40 is supplied (reaches) the target position J. In this way, in the supply mechanism 4, the nut N received by the stopper 65 is supplied to the target position J by the forward movement of the rod 40.

The bushing 81 attempts to move forward in response to the forward movement of the rod 40. However, the lid 52 is located in front of the bushing 81. As the bushing 81 follows the forward movement of the rod 40, it comes into contact with the rear end surface of the lid 52. More specifically, as the bushing 81 moves forward in response to the forward movement of the rod 40, it comes into contact with the rear end surface of the lid 52.

After the bushing 81 comes into contact with the lid 52, a rearward pressing force P acts from the lid 52 on the bushing 81. As the lid 52 applies the rearward pressing force P to the bushing 81, the coil spring 82 (connected to the bushing 81) contracts from its natural length. A forward restoring force F acts from the coil spring 82 on the bushing 81. Due to the rearward pressing force P from the lid 52 to the bushing 81, the bushing 81 moves rearward relative to the rod 40 against the forward restoring force F from the coil spring 82 to the bushing 81. In other words, the bushing 81 that comes into contact with the lid 52 does not move forward, but the rod 40 does. The bushing 81, which moves rearward relative to the rod 40, blocks the air inlet 45.

The bushing 81 of the sealing mechanism 80 blocks the air inlet 45 of the rod 40, thereby sealing off the flow of air A from the air chamber R to the air inlet 45.

In summary, after contacting the lid 52, the bushing 81 moves rearward relative to the rod 40 due to the rearward pressing force P from the lid 52 on the bushing 81, resisting the forward restoring force F from the coil spring 82 on the bushing 81, thereby closing the air inlet 45.

As the rod 40 advances, it supplies the nut N to the target position J, and at the same time, the bushing 81 closes the air inlet 45.

As the piston 50 advances further, the volume of the air chamber R becomes even smaller. The air A in the air chamber R is further compressed. However, the bushing 81 blocks the air inlet 45. As a result, the compressed air A is not introduced from the air chamber R into the air inlet 45.

Since air A is no longer introduced into the air inlet 45, it no longer moves through the air passage 46 and is no longer blown out from the air outlet 44. Air A is no longer blown out from the air outlet 44 toward the nut N hung on the front end 41 of the rod 40. The nut N hung on the front end 41 of the rod 40 is no longer pressed against the stepped surface 43 of the rod 40. The nut N is no longer held by the front end 41 of the rod 40.

At the target position J, the nut N is removed from the front end 41 of the rod 40. The removed nut N is then placed between the lower electrode 104 and the upper electrode 109 of the resistance welding machine 100, which serves as the target position J.

Air A compressed in the air chamber R does not flow out into the external space E outside the cylinder 51 through the check valve 70.

Figure 14 shows the state after the rod 40 has retreated (retracted) from the target position J. The actuator 53 retracts the drive rod 53b rearward through the electrical action of the electric mechanism 53a. The piston 50, connecting member 90, and rod 40 retract.

When the nut N is removed at the target position J, the front end 41 of the rod 40 retreats (moves back) from the target position J.

As the rod 40 retracts, the rearward pressing force P from the lid 52 on the bushing 81 decreases, causing the coil spring 82 (connected to the bushing 81) to expand. The forward restoring force F from the coil spring 82 on the bushing 81 causes the bushing 81 to move forward relative to the rod 40. In other words, even though the rod 40 retracts, the bushing 81 no longer retracts. As a result, the bushing 81 moves forward relative to the air inlet 45. The air inlet 45 is no longer blocked by the bushing 81, and the air inlet 45 is opened.

As the rod 40 moves further backward, the bushing 81 is released from contact with the lid 52, the rearward pressing force P from the lid 52 on the bushing 81 becomes zero, and the coil spring 82 extends to its natural length (returns to its original state). At this time, the forward restoring force F from the coil spring 82 on the bushing 81 becomes zero. The bushing 81 then returns to its original position and is positioned forward of the air inlet 45. The blockage of the air inlet 45 by the bushing 81 is fully released, and the air inlet 45 is fully open.

After the coil spring 82 reaches its natural length, the bushing 81 also retracts, following the retraction of the rod 40 (the bushing 81 retracts integrally with the rod 40).

As the piston 50 retracts, the volume of the air chamber R increases. Air A in the air chamber R expands. Although the air inlet 45 is open, the expanded air A is not introduced into the air inlet 45. Air A does not move through the air passage 46 and is not blown out from the air outlet 44.

The check valve 70 allows (opens) the flow of air A from the external space E outside the cylinder 51 into the air chamber R inside the cylinder 51. As the volume of the air chamber R increases (as the air A in the air chamber R expands), air A (atmospheric air) in the external space E flows from the external space E into the air chamber R via the check valve 70.

Returning to Figure 11, the front end 41 of the rod 40 is positioned rearward of the nut receiving chamber 66 (rearward of the rod through-hole 64). The next nut N sent from the chute 3 to the nut receiving chamber 66 via the connecting pipe 5 is received and caught by the stopper 65. The door 63 is closed rearward by the restoring force of the spring attached to the hinge.

The above process is then repeated.

<Resistance welding machine>
1, a nut transfer system 1 is applied to a resistance welding machine 100. The nut transfer system 1 and the resistance welding machine 100 constitute a nut welding system S.

The nut transfer system 1 transfers the nut N to a destination position J. The destination position J is located between the lower electrode 104 and the upper electrode 109, which are a pair of electrodes in the resistance welding machine 100. The destination position J is located below the direction change guide 24 (upper position G1) of the lifting mechanism 2. The destination position J may also be located below the receiving tray 25 (lower position G2).

The resistance welding machine 100 comprises a pair of electrode units: a lower electrode unit 101 and an upper electrode unit 102. As will be described in detail later, the lower electrode unit 101 includes a lower electrode 104, and the upper electrode unit 102 includes an upper electrode 109. In other words, the resistance welding machine 100 comprises a pair of electrodes: a lower electrode 104 and an upper electrode 109.

The resistance welding machine 100 welds the workpiece W and nut N while sandwiching them between the lower electrode 104 of the lower electrode unit 101 and the upper electrode 109 of the upper electrode unit 102. The workpiece W is, for example, a metal plate-shaped member. The lower electrode unit 101 (lower electrode 104) is fixed in place. The upper electrode unit 102 (upper electrode 109) moves up and down.

Figure 19 shows the lower electrode unit 101 of the resistance welding machine 100. As shown in Figure 19, the lower electrode unit 101 includes a lower holder 103, a lower electrode 104 as an electrode, a guide pin 105, a guide pin actuator 106, and an interposition rod 107. The lower holder 103 is cylindrical and extends vertically. The lower holder 103 is fixed in place.

The lower electrode 104 is disposed at the upper end of the lower holder 103. The lower electrode 104 covers the upper end of the lower holder 103. The workpiece W is placed on the upper end 104a, which is the tip of the lower electrode 104. The upper end surface of the lower electrode 104 forms the mounting surface on which the workpiece W is placed. The upper end 104a of the lower electrode 104 contacts the underside of the workpiece W. A through-hole 104b that penetrates vertically is formed in the center of the lower electrode 104.

The guide pin 105 is rod-shaped and extends vertically. The guide pin 105 moves vertically within the lower holder 103. The guide pin 105 passes through the through-hole 104b of the lower electrode 104, protruding upward from the upper end 104a, which serves as the tip of the lower electrode 104, and retracting downward from the upper end 104a, which serves as the tip of the lower electrode 104. In other words, the guide pin 105 protrudes upward and retracts downward from the upper end (tip) 104a of the lower electrode 104.

The guide pin 105 is used to position the nut N. The workpiece W has a hole Wa formed therethrough in the thickness direction (vertical direction). The guide pin 105 is inserted from below to above through the hole Wa of the workpiece W (placed on the upper end 104a of the lower electrode 104).

The upper end of the guide pin 105 (inserted through the hole Wa in the workpiece W) protrudes above the top surface of the workpiece W, which is placed on the upper end 104a of the lower electrode 104. The screw hole N2 of the nut N supplied by the supply mechanism 4 to the destination position J (between the lower electrode 104 and upper electrode 109, which form a pair of electrodes) fits into the upper end of the guide pin 105 (protruding above the top surface of the workpiece W). The protrusion N3 on the back surface N1b of the nut N faces the top surface of the workpiece W below. The guide pin 105 positions the nut N on the top surface of the workpiece W.

The guide pin actuator 106 is a known retraction actuator. The guide pin actuator 106 includes a cylinder 106a, a piston 106b, a drive rod 106c, and a coil spring 106d as an elastic member.

The cylinder 106a is cylindrical. The axis of the cylinder 106a extends vertically. The cylinder 106a is positioned below the lower end of the lower holder 103. The upper and lower ends of the cylinder 106a are closed by upper and lower wall portions. A through hole is drilled in the upper wall portion of the cylinder 106a.

The piston 106b is housed inside the cylinder 106a. The drive rod 106c is housed inside the cylinder 106a. The drive rod 106c is rod-shaped and extends vertically. The lower end of the drive rod 106c is fixed to the upper surface of the piston 106b. The drive rod 106c starts from the upper surface of the piston 106b and extends upward, passing through a through-hole in the upper wall of the cylinder 106a and continuing upward, protruding outside the cylinder 106a. The upper end of the drive rod 106c is located above (outside) the upper wall of the cylinder 106a. The upper end of the drive rod 106c is inserted into the lower holder 103 from below through an opening in the lower end of the lower holder 103.

The coil spring 106d is coil-shaped. The coil spring 106d is housed inside the cylinder 106a. Inside the cylinder 106a, the coil spring 106d is positioned below the piston 106b and above the bottom wall of the cylinder 106a. The coil spring 106d pushes the piston 106b and drive rod 106c upward with an elastic force V acting as a biasing force.

The intervening rod 107 is rod-shaped and extends vertically. The intervening rod 107 is disposed (intervened) within the lower holder 103. Within the lower holder 103, the intervening rod 107 is disposed below the guide pin 105 and above the drive rod 106c of the guide pin actuator 106. The intervening rod 107 may connect the lower end of the guide pin 105 and the upper end of the drive rod 106c.

The guide pin actuator 106 pushes the piston 106b and drive rod 106c upward with the elastic force (biasing force) V of the coil spring 106d, thereby pushing the guide pin 105 upward via the intervening rod 107.

When the guide pin 105 is in an unloaded state, where no downward load is applied, the guide pin 105 protrudes upward from the upper end (tip) 104a of the lower electrode 104 due to the upward elastic force (biasing force) V of the coil spring (elastic member) 106d of the guide pin actuator 106. In other words, the coil spring (elastic member) 106d of the guide pin actuator 106 biases the guide pin 105 upward (via the piston 106b, drive rod 106c, and intervening rod 107) so that the guide pin 105 protrudes upward from the upper end (tip) 104a of the lower electrode 104.

When a downward load is applied to the guide pin 105, the guide pin 105 is pressed downward against the upward elastic force (biasing force) V of the coil spring (elastic member) 106d of the guide pin actuator 106, causing it to retract downward from the upper end (tip) 104a of the lower electrode 104. The downward load on the guide pin 105 is exerted by downward pressure from the upper electrode 109.

Returning to Figure 1, the upper electrode unit 102 includes an upper holder 108, an upper electrode 109 as an electrode, and an upper actuator 110. The upper holder 108 is cylindrical and extends vertically. The upper holder 108 moves vertically.

The upper electrode 109 is disposed at the lower end of the upper holder 108. The upper electrode 109 covers the lower end of the upper holder 108. When the upper holder 108 moves downward, the lower end 109a, which serves as the tip of the upper electrode 109, comes into contact with the surface N1a of the nut N (see Figure 10).

The upper actuator 110 is positioned above the upper holder 108. The upper actuator 110 is an electric actuator. The upper actuator 110 is composed of, for example, an electromagnetic solenoid, a ball screw mechanism, a linear motor, a servo motor, a stepping motor, or a rack gear motor. The upper actuator 110 moves the upper holder 108 and the upper electrode 109 up and down by electrical action.

<Action and effect>
According to this embodiment, the nut N is raised from the receiving tray 25 (lower position G2) to the direction change guide 24 (upper position G1) in the lifting mechanism 2, falls downward from the direction change guide 24 (upper position G1) of the lifting mechanism 2 through the chute 3, is received by the stopper 65 of the supply mechanism 4, and is supplied to the target position J by the advancement of the rod 40 of the supply mechanism 4.

The chute 3 extends downward from the direction change guide 24 (upper position G1) of the lifting mechanism 2 to the supply mechanism 4 without returning upward. The nut N naturally falls downward due to gravity in the chute 3, without returning upward, from the direction change guide 24 (upper position G1) of the lifting mechanism 2 to the supply mechanism 4.

This reduces (and preferably eliminates) the need for an air pumping device to pump air A to move the nut N from bottom to top against gravity in the chute 3. This reduces the need for an air supply source (such as an air pump) to supply air A to such an air pumping device.

As a result, the air supply source can be reduced in the nut transfer system 1 that transfers nuts N to the destination position J.

The nut N is attracted to the outer surface 11 of the outer cylinder 10 by some of the multiple magnets 13 arranged in a spiral. As the magnets 13 rotate around the central axis O, the nut N attempts to rotate circumferentially along the outer surface 11 of the outer cylinder 10. However, the rotational movement of the nut N is restricted by the restricting guide 16. In other words, even though the magnets 13 rotate, the nut N does not rotate.

Because the multiple magnets 13 are arranged in a spiral and the axial direction of the outer cylinder 10 extends vertically, as the multiple magnets 13 rotate, the second magnet 13B, third magnet 13C, fourth magnet 13D, etc., which are located upstream of the first magnet 13A in the rotational direction (counterclockwise circumferentially), appear one after another above the nut N. The nut N is attracted sequentially to the second magnet 13B, third magnet 13C, fourth magnet 13D, etc., which appear one after another, and moves axially upward along the outer surface 11 of the outer cylinder 10.

The lifting mechanism 2 allows the nut N to be lifted upward with a simple configuration.

In the lifting mechanism 2, the front and back sorting guide 21 can sort the front and back of the nut N and convert it into a uniform position.

The lifting mechanism 2 can efficiently lift the nut N upward from the tray 25 located in the lower position G2.

In particular, the lifting mechanism 2 allows the front/back sorting guide 21 and tray 25 to be viewed below the worker's eye level, making work easier and safer than when viewing them above the worker's eye level.

By changing the direction of the nut N from above to below using the direction change guide 24 located at the upper position G1 in the lifting mechanism 2, the nut N can be smoothly sent downward to the chute 3 in the subsequent process.

Furthermore, the use of an air pumping device to pump air A to change the direction of the nut N from above to below can be reduced, contributing to a reduction in the air supply source.

In the chute 3, the nut N slides against the long plate member 32 arranged inside the tubular member 31, preventing the nut N from coming into direct contact with the inner surface of the tubular member 31, thereby reducing damage to the tubular member 31.

Furthermore, because the nut N falls smoothly downward through the chute 3, the need for an air pumping device to pump the nut N downward through the chute 3 with air A can be reduced, contributing to a reduction in the air supply source.

By bending the flexible tubular member 31, the elastically deformable long plate member 32 can also be deformed. Furthermore, because the long plate member 32 is harder than the tubular member 31, frictional resistance when the nut N slides against the long plate member 32 can be reduced, making it easier for the nut N to slide against the long plate member 32. The nut N can be dropped from the chute 3 even when the chute 3 is snaked back and forth or left and right, or when the chute 3 is twisted. A reduction in the dropping speed of the nut N from the chute 3 can be suppressed.

Furthermore, because the nut N falls smoothly downward through the chute 3, the need for an air pumping device to pump the nut N downward through the chute 3 with air A can be reduced, contributing to a reduction in the air supply source.

In the chute 3, there is a concern that the cylindrical member 31 may be damaged if the protrusion N3 of the nut N comes into contact with the cylindrical member 31. However, by allowing the protrusion N3 of the nut N to slide against the long plate member 32, the protrusion N3 of the nut N is prevented from coming into direct contact with the inner surface of the cylindrical member 31, thereby preventing damage to the cylindrical member 31.

Furthermore, because the nut N falls smoothly downward through the chute 3, the need for an air pumping device to pump the nut N downward through the chute 3 with air A can be reduced, contributing to a reduction in the air supply source.

In the supply mechanism 4, the actuator 53 does not need to use an air supply source to move the rod 40 back and forth.

As the rod 40 advances, the front end 41 of the rod 40 is inserted into the through-hole N2 of the nut N. The nut N hung on the front end 41 of the rod 40 is supplied to the target position J as the rod 40 advances.

Air A is stored in air chamber R, which is defined by piston 50, cylinder 51, and lid 52. When piston 50 moves forward, air A in air chamber R is compressed. The compressed air A in air chamber R is introduced into air inlet 45 of rod 40. Air A introduced into air inlet 45 passes through air passage 46 in interior 40a of rod 40 and is blown out from air outlet 44 on outer periphery 47 of front end 41 of rod 40.

Air A is blown out from air outlets 44 on the outer periphery 47 of the front end 41 of the rod 40 toward the nut N attached to the front end 41 of the rod 40. This holds the nut N in place on the front end 41 of the rod 40.

The supply mechanism 4 utilizes an air chamber R partitioned by a piston 50, a cylinder 51, and a lid 52, so air A can be blown out from the air outlet 44 to hold the nut N at the front end 41 of the rod 40 without using an air supply source.

At the target position J, the guide pin 105 can be extended and retracted from the upper end (tip) 104a of the lower electrode 104 without using an air supply source.

The nut welding system S (nut transfer system 1 and resistance welding machine) of this embodiment can achieve airless operation without an air supply source (in particular, it can achieve a completely airless operation without any air supply source).

<Other embodiments>
Although the present disclosure has been described above with reference to preferred embodiments, such description is not limiting, and it goes without saying that various modifications, substitutions, or combinations are possible.

A connecting member may be interposed between the drive rod 53b of the actuator 53 and the piston 50. The piston 50 and the rod 40 may be directly connected without the connecting member 90 being interposed between them.

"Cylindrical" is not limited to cylindrical shapes, but can also include rectangular cylindrical shapes.

The lid 52 may not be located at the front end of the cylinder 51, but may be located at an intermediate portion of the cylinder 51, rearward of the front end. The cylinder 51 and the lid 52 may be integrally formed as a single member.

The rod 40 may have a portion rearward of the rear portion 42 that is smaller in diameter than the rear portion 42 (and even smaller in diameter than the front end portion 41). An air inlet 45 may be provided in this smaller diameter portion. The air inlet 45 may be provided not on the outer periphery 47 of the rod 40, but at the rear end of the rod 40, for example.

The actuator 53 does not have to be an electric actuator, but may be, for example, a hydraulic actuator (hydraulic cylinder mechanism) or a pneumatic actuator (air cylinder mechanism).

In the lifting mechanism 2, the central axis of the spiral C, the central axis of the shaft 14, and the central axis of the outer cylinder 10 may be eccentric with respect to one another. The outer cylinder 10 may be inclined with respect to the vertical axis.

The tray 25 does not necessarily have to be provided at the lower position G2 of the lifting mechanism 2; for example, the nut N may be manually placed at the lower position G2 of the lifting mechanism 2. The direction change guide 24 does not necessarily have to be provided at the upper position G1 of the lifting mechanism 2; for example, the lifting mechanism 2 may be directly connected to the chute 3 at the upper position G1.

In the chute 3, the long plate member 32 may be provided only on a portion of the chute 3. For example, it may be provided only on the serpentine portion of the chute 3 where the nut N is most likely to come into contact with the cylindrical member 31. In the chute 3, the surface N1a of the nut N, which does not have the protrusion N3, may slide against the long plate member 32. In the chute 3, the long plate member 32 does not have to be made of metal, and may be made of, for example, an elastically deformable hard plastic. The long plate member 32 may not be present in the chute 3.

In the chute 3, the cross section of the tubular member 31 is not limited to a square shape and may be, for example, a circle, a cross, or a key shape. In the chute 3, the tubular member 31 does not have to be made of resin.

The guide pin actuator 106 does not have to be a retraction actuator, and may be, for example, an electric actuator (electric cylinder mechanism), a hydraulic actuator (hydraulic cylinder mechanism), or a pneumatic actuator (air cylinder mechanism). The elastic member 106d of the guide pin actuator 106 is not limited to a coil spring, and may be, for example, a leaf spring, a resin spring, a rubber spring, etc.

The upper electrode unit 102 may include a guide pin and a guide pin actuator. The guide pin may protrude downward and retract upward from the lower end (tip) 109a of the upper electrode 109.

The nut N does not have to have the protrusion N3.

The nut N is not limited to a square nut, but may be, for example, a polygonal nut other than a square nut, or a circular nut.

Part N may be a nut, a washer or a sleeve with a through hole, etc.

Part N may be, for example, a bolt without a through-hole. Figure 20 shows a bolt transfer system 1 as a part transfer system according to another embodiment. In this case, in the bolt transfer system 1, a bolt holder 48, which serves as a well-known holder, is fixed to the tip of the rod 40 in the supply mechanism 4. The bolt holder 48 is provided with a stopper 65 that receives the bolt N. The supply mechanism 4 receives the bolt N as a part that has fallen from the chute 3 using the stopper 65 of the bolt holder 48 at the tip of the rod 40. The supply mechanism 4 supplies the bolt N as a part received by the stopper 65 of the bolt holder 48 at the tip of the rod 40 to the destination position J by advancing the rod 40.

Figure 21 shows a resistance welding machine 100 according to another embodiment. The upper actuator 110 is positioned above the upper holder 108. The upper actuator 110 is an electric actuator. The upper actuator 110 moves the upper holder 108 and the upper electrode 109 up and down by electrical action. The upper actuator 110 includes a cylinder 110a, a piston 110b, a drive rod 110c, a driven rod 110d, a vertical drive mechanism 110e, and a lid 110f.

The cylinder 110a is cylindrical and is positioned above the upper holder 108. The piston 110b is positioned within the cylinder 110a. The drive rod 110c is connected to the piston 110b and extends upward from the upper surface of the piston 110b. The upper end of the drive rod 110c is connected to a vertical drive mechanism 110e (e.g., a drive motor or an electromagnetic solenoid) for reciprocating the drive rod 110c up and down.

The driven rod 110d is connected to the piston 110b and extends downward from the underside of the piston 110b. The lower end of the driven rod 110d is connected to the upper holder 108. The lower opening of the cylinder 110a is closed by the lid 110f. The cylinder 110a, the lid 110f, and the piston 110b define the air chamber 110g.

A hole 110i is provided in the side wall 110h of the cylinder 110a. The hole 110i faces the air chamber 110g and connects the inside and outside of the air chamber 110g. One end of a hose 110j is connected to the hole 110i in the side wall 110h of the cylinder 110a.

A cover 110k is provided between the lower end of the lower holder 103 and the upper end of the cylinder 106a of the guide pin actuator 106, covering both of them. A hole 110l is provided in the cover 110k. The hole 110l connects the inside and outside of the cover 110k. The other end of the hose 110j is connected to the hole 110l in the cover 110k. The internal space of the cover 110k is connected to the gaps between the inner surface 103a of the lower holder 103 and the inner surface 104c of the lower electrode 104 and the outer surface 105a of the guide pin 105.

In summary, the resistance welding machine 100 includes an upper actuator 110 serving as an actuator for the resistance welding machine. The upper actuator 110 moves (the upper holder 108 and) the upper electrode 109 downward, and at the same time, moves a piston 110b serving as a piston for the resistance welding machine, which is disposed within a cylinder 110a serving as a cylinder for the resistance welding machine, downward, thereby compressing an air chamber 110g serving as a gas chamber for the resistance welding machine.

Air chamber 110g is connected via hose 110j to the gaps between the inner surface 103a of the lower holder 103 and the inner surface 104c of the lower electrode 104 and the outer surface 105a of the guide pin 105. In other words, air chamber 110g is connected to the inner surface 103a of the lower holder 103 and the inner surface 104c of the lower electrode 104. Air chamber 110g is connected to the outer surface 105a of the guide pin 105.

Air A as gas compressed in air chamber 110g escapes upward through the gaps between the inner surface 103a of the lower holder 103 and the inner surface 104c of the lower electrode 104 and the outer surface 105a of the guide pin 105. Air A as gas compressed in air chamber 110g escapes upward along the inner surface 103a of the lower holder 103 and the inner surface 104c of the lower electrode 104. Air A as gas compressed in air chamber 110g escapes upward along the outer surface 105a of the guide pin 105.

Debris (welding dust, etc.) generated during the resistance welding process using the resistance welding machine 100 can be removed by blowing air A (air blow) without using an air supply source.

Part N may also be, for example, a crimp bolt, crimp nut, pierce bolt, or pierce nut.

Instead of air A, nitrogen gas, for example, may be used as the gas.

The application field of the part transfer system 1 is not limited to the resistance welding machine 100. The destination position J can be anything. For example, a crimping mechanism or a piercing mechanism may be located at the destination position J.

This disclosure is extremely useful and has high industrial applicability as it can be applied to part transfer systems and part welding systems.

Z: Up-down direction Z1: Up Z2: Down X: Front-rear direction X1: Forward X2: Backward Y: Left-right direction O: Central axis C: Spiral H: Gap L: Gap G1: Upper position G2: Lower position J: Target position R: Air chamber (gas chamber)
E. External space A. Air (gas)
F restoring force (biasing force)
P: Pressing force N: Nut (part, bolt)
N1 Main body N1a Front surface N1b Back surface N1c Side surface N2 Screw hole (through hole)
N3 Projection t Thickness T Thickness s Two-sided width dimension e Diagonal dimension W Workpiece Wa Hole V Elastic force (biasing force)
S Nut welding system 1 Nut transfer system (parts transfer system, bolt transfer system)
2 Lifting mechanism 3 Chute 4 Supply mechanism 5 Connecting pipe 5a Groove portion 5b Lid portion 10 Outer cylinder 11 Outer surface 12 Inner surface 13 Magnet (attraction portion)
13a Small magnet 13b Small magnet 13c Midpoint 13A First magnet 13B Second magnet 13C Third magnet 13D Fourth magnet 14 Shaft (rotation drive part)
14a Outer surface 15 Motor (rotation drive unit)
15a Arrow 16 Restriction guide (restriction portion)
17 First guide portion 18 Second guide portion 18a Fixing portion 19 Posture change guide (posture change portion)
19a First chamfered portion 19b Second chamfered portion 20 Stopper guide 20a Alignment guide (through hole)
21 Front and back sorting guide (front and back sorting section)
21a Mounting portion 21b Protruding portion 22 Protrusion prevention guide 23 Upper guide 23a Groove bottom wall 23b Groove side wall 24 Direction change guide (direction change portion)
24a Side wall 24b Upper wall 24c Lower wall 24d Inlet 25 Receptacle (reservoir)
26 Base 31 Cylindrical member 31a First inner surface 31b Second inner surface 31c Inner groove 32 Long plate member 32a Back surface 32b Front surface 40 Rod 40a Inside 41 Front end portion 42 Rear portion 43 Step surface 44 Air outlet (gas outlet)
45 Air inlet (gas inlet)
46 Air passage (gas passage)
47 Outer periphery 48 Bolt holder 50 Piston 51 Cylinder 52 Lid 52a Main body 52b Fitting portion 52c Hole 53 Actuator 53a Electric mechanism 53b Drive rod 60 Nut receiver (part receiver)
61 Holder 61a Main body 61b Fitting portion 62 Receiving portion 62a Rear wall 62b Side wall 63 Door 64 Rod through-hole 65 Stopper 66 Nut receiving chamber (part receiving chamber)
67 Discharge hole 70 Check valve 80 Sealing mechanism 81 Bush 82 Coil spring (biasing member)
90 Connecting member 100 Resistance welding machine 101 Lower electrode unit 102 Upper electrode unit 103 Lower holder 103a Inner surface 104 Lower electrode (electrode)
104a Upper end (tip)
104b Through hole 104c Inner surface 105 Guide pin 105a Outer surface 106 Guide pin actuator 106a Cylinder 106b Piston 106c Drive rod 106d Coil spring (elastic member)
107 Interposition rod 108 Upper holder 109 Upper electrode (electrode)
109a Lower end (tip)
110 Upper actuator (resistance welding machine actuator, electric, blow mechanism actuator)
110a Cylinder (cylinder for resistance welding machine, cylinder for blow mechanism)
110b Piston (resistance welding machine piston, blow mechanism piston)
110c: drive rod; 110d: driven rod; 110e: up-down drive mechanism; 110f: lid; 110g: air chamber (gas chamber for resistance welding machine, gas chamber for blow mechanism)
110h Side wall 110i Hole 110j Hose 110k Cover 110l Hole

Claims (11)

a parts transfer system;
a resistance welding machine;
The part transfer system includes:
a lifting mechanism for lifting the part from a lower position to an upper position;
a chute that drops the parts sent from the upper position of the lifting mechanism;
a supply mechanism that receives the part dropped from the chute with a stopper and supplies the part received by the stopper to a target position by advancing a rod;
the chute extends downward from the upper position of the lifting mechanism to the feeding mechanism without returning upward;
the resistance welding machine includes a lower electrode and an upper electrode;
the target position is between the lower electrode and the upper electrode;
A guide pin protrudes and retracts from the tip of the lower electrode,
the guide pin protrudes from the tip by an elastic force of an elastic member, and retracts from the tip by being pressed against the elastic force of the elastic member;
the resistance welding machine includes a resistance welding machine actuator that moves the upper electrode up and down;
the resistance welding machine actuator is an electric actuator,
the resistance welding actuator includes a resistance welding cylinder and a resistance welding piston disposed in the resistance welding cylinder;
the resistance welding cylinder and the resistance welding piston define a resistance welding gas chamber,
the gas chamber for the resistance welding machine is disposed below the piston for the resistance welding machine,

the gas chamber for the resistance welding machine communicates with the outer surface side of the guide pin via a hose;
the resistance welding machine actuator moves the upper electrode downward and simultaneously moves the resistance welding machine piston downward, thereby compressing the gas in the resistance welding machine gas chamber;
A parts welding system, wherein the gas compressed in the gas chamber for the resistance welding machine escapes upward along the outer surface of the guide pin. The lifting mechanism includes:
An outer cylinder extending vertically;
a plurality of suction sections arranged in a spiral shape having a central axis extending vertically on the inner surface of the outer cylinder, the suction sections applying a magnetic field to the outer surface of the outer cylinder to suction the parts to the outer surface of the outer cylinder;
a rotation drive unit that rotates the plurality of suction units around the central axis;
The part welding system according to claim 1 , further comprising: a restricting unit that restricts rotational movement of the part to move the part upward along the outer surface of the outer cylinder. The lifting mechanism has a front and back sorting unit,
The part welding system according to claim 2, wherein the front/back sorting unit allows the part to pass when the front surface faces the outer surface, and rejects the part to prevent passage when the back surface faces the outer surface, based on a difference in protruding thickness from the outer surface of the outer cylinder. The part welding system of claim 2, wherein the lifting mechanism has a reservoir portion in the lower position for storing multiple parts. The part welding system of claim 2, wherein the lifting mechanism has a redirecting section that redirects the part moving upward along the outer surface of the outer cylinder downward at the upper position. The shooter is
a cylindrical member through which the part passes;
a long plate member disposed inside the cylindrical member and extending along the cylindrical member,
The part welding system according to claim 1 or 2, wherein the part slides on the long plate member. The cylindrical member is made of a flexible material,
7. The parts welding system according to claim 6, wherein the elongated plate member is made of a material that is harder than a material that constitutes the tubular member and that is elastically deformable. The part has a protrusion provided on a rear surface,
The part welding system of claim 6 , wherein the protrusion of the part slides on the elongated plate member. the supply mechanism has an actuator that moves the rod back and forth,
The part welding system according to claim 1 or 2, wherein the actuator is an electric actuator. The supply mechanism includes:
the rod that advances to supply the part having a through-hole to the target position;
a piston coupled to the rod;
a cylinder that accommodates the rod and the piston;
a lid that closes the cylinder forward of the piston and through which the rod extending forward from the piston passes;
an actuator that moves the piston and the rod back and forth,
the piston, the cylinder, and the lid define a gas chamber;
The rod is
a gas outlet provided on an outer periphery of a front end portion of the rod inserted into the through hole of the part, the gas outlet blowing out;
a gas inlet port provided rearward of the gas outlet and through which the gas is introduced from the gas chamber;
The part welding system according to claim 1 or 2, further comprising: a gas passage extending longitudinally inside the rod and through which the gas passes from the gas inlet to the gas outlet. A lower electrode;
an upper electrode;
an actuator for a resistance welding machine that moves the upper electrode up and down;
A guide pin protrudes and retracts from the tip of the lower electrode,
the guide pin protrudes from the tip by an elastic force of an elastic member, and retracts from the tip by being pressed against the elastic force of the elastic member;
the resistance welding machine actuator is an electric actuator,
the resistance welding actuator includes a resistance welding cylinder and a resistance welding piston disposed in the resistance welding cylinder;
the resistance welding cylinder and the resistance welding piston define a resistance welding gas chamber,
the gas chamber for the resistance welding machine is disposed below the piston for the resistance welding machine,
the gas chamber for the resistance welding machine communicates with the outer surface side of the guide pin via a hose;
the resistance welding machine actuator moves the upper electrode downward and simultaneously moves the resistance welding machine piston downward, thereby compressing the gas in the resistance welding machine gas chamber;
The gas compressed in the gas chamber for the resistance welding machine escapes upward along the outer surface of the guide pin.