JPH0431795B2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention is applicable to parts such as projection nuts with welding protrusions, short thick pipes, or bolts with heads. Regarding the supply method for supplying.

(B) Prior art The prior art that is considered to be closest to the present invention is the technology disclosed in Japanese Patent Publication No. 59-7549 (B23K11/14), the main points of which are shown in Figures 9 and 10.
It is shown in the figure. In this structure, an inner shaft 2 is slidably assembled inside a hollow outer shaft 1, and a magnet (permanent magnet) 4 that attracts a component (projection nut) 3 is fixed to the tip of the inner shaft 2. be. The outer cylinder 5 housing the outer shaft 1 is fixed to a stationary member 6 as shown in the figure, and the outer shaft 1 is inserted into a guide groove 7 provided in the inner surface of the outer cylinder 5 in the stroke direction.
A pin 8 fixed to is inserted. The other sheet metal part 9 is placed on the fixed electrode 10, and the guide pin 11 of the fixed electrode passes through the hole in the sheet metal part 9 and extends upward.

The end surfaces of both shafts 1 and 2 are aligned on one plane to be flush, and the nut 3 is attracted thereto. In this state, when both shafts advance together and reach a certain point, the advancement of the inner shaft 2 is prohibited, only the outer shaft 1 advances, and the nut 3 is moved to the magnet as shown in Fig. 10. 4, and the magnetic force on the nut 3 is substantially eliminated. By doing this, the nut 3 moves away from the lower end surface of the outer shaft 1 and jumps toward the guide pin 11, so that the guide pin 11 is fitted into the screw hole of the nut 3. Supply is completed.
Note that the distance L of spatial movement is illustrated in FIG.

Although the above-mentioned structure for prohibiting the advancement of the inner shaft 2 is not shown, a restriction pin fixed to the inner shaft 2 is protruded from a long hole in the outer shaft, and both shafts 1 and 2 are advanced by a certain amount. Then, by locking the regulating pin with a stationary member, the advancement of the inner shaft 2 is forcibly stopped, and only the outer shaft 1 moves forward as shown in FIG. The attraction force is reduced, and the guide pin 11 is inertially pushed down and fitted together.

(c) Problems to be Solved by the Invention In the prior art as described above, the attractive magnetic force on the nut 3 substantially disappears during the transition period when the magnet stops and the outer shaft moves further forward. Therefore, the following problems arise. In other words, the first problem is that the magnetic force on the nut gradually decreases while only the outer shaft is moving, so some external force or vibration may be applied to the nut by the time the nut reaches a predetermined location. If this occurs, the nut may fall off inadvertently, resulting in a feeding error. The second problem is that it depends on the phenomenon in which the attractive magnetic force to the nut virtually disappears, so due to variations in the weight of the nut or the stickiness of oil attached to the nut, the nut may become attached to the outer layer. The timing at which the nut leaves the shaft is not constant, and as a result, the spatial movement distance of the nut varies, which poses a problem in stabilizing the supply accuracy. And, because of the long and short distances mentioned above,
It is necessary to set the distance to a certain extent according to the longest case, and this point also lengthens aerial movement and causes supply errors.

When we further investigate the cause of the above-mentioned problem, we find that it is caused by the structure of the magnet installation. In other words, since the magnet of the conventional technology is fixed to the tip of the inner shaft as shown in the figure, if the screw hole is open like a nut, it is impossible to make the attractive magnetic force to the nut a sufficiently large value. Therefore, the nut may fall due to external force or vibration as mentioned above.

A more important problem is that if the attractive magnetic force is insufficient, it is impossible to increase the forward speed of the supply rod, which is very disadvantageous in terms of shortening the supply time of parts.

(d) Means for solving the problem and its effect The present invention was provided in order to solve the above-mentioned problems. A magnet that applies a suction force to the outer surface is installed in a position protruding from the supply rod so that it can move forward and backward, and when the supply rod is in the forward movement near the end of its forward stroke, the magnet is driven in the opposite direction to the advancing direction of the supply rod. It is characterized by forcibly retracting the parts by a device, and the attraction force of the magnet applied to the outer surface of the parts applies a constant and strong attraction magnetic force while the supply rod is moving forward, so that the parts do not reach the target. The attraction force of the magnet is quickly extinguished while the rod is moving forward before reaching the target location, thereby completing the supply to the target location.

(e) Embodiment To explain the embodiments shown in FIGS. 1 to 5, this is a case of a spot welding apparatus as shown in FIG. The guide pin 14 of the same electrode protrudes from the steel plate component 12. Reference numeral 15 is a movable electrode installed coaxially with the fixed electrode 13.

The supply unit 16 incorporating the supply rod according to the present invention includes a projection nut (in this embodiment, it is a projection nut).
17 supply pipes 18 are connected thereto, and an air cylinder 19 is also connected thereto. The end face of the supply rod 20 is adapted to fit a nut 17 in close contact with it, as shown by the two-dot chain line in FIG. 1, and is provided with a protrusion 21 for holding the nut 17 from the outside. Protrusion 2 shown
1 is shaped like a U-shaped frame as shown in Figure 3. The feed rod 20 is suitably made of stainless steel.

A magnet 22 that applies a suction force to the outer surface of the nut 17 is located at a position protruding from the end surface of the supply rod 20 and is movable toward and away from the supply rod 20. In this embodiment, the supply rod 20 has a double inner and outer structure in order to move the magnet 22 forward and backward.The supply rod 20 itself has a hollow shaft 23, and an inner shaft 24 is slidably inserted into the hollow shaft 23.
has been inserted. The magnet 22 is connected to a sliding body 25 that is in contact with the outer surface of a hollow shaft 23, and the inner shaft 24 and the sliding body 25 are integrated via a bolt 26. A long hole 27 is formed in the hollow shaft 23 in the stroke direction, and the bolt 26 passes through this long hole.

The lower end surface of the inner shaft 24 can be brought into close contact with the nut 17 so as to form the same plane as the lower end surface of the hollow shaft 23, and there is a small magnet (permanent magnet) therein for applying a light upward attractive force to the nut 17. 28 is embedded.

The supply rod 20 is housed in an outer cylinder 29 with a gap as shown in the figure, and an air cylinder 19 is connected to the upper side of the outer cylinder 29, and a supply pipe 18 is welded to the lower side. A piston rod 30 of the air cylinder 19 is connected to the supply rod 20. A regulating pin 31 is fixed to the inner shaft 24 and projects from the supply rod 20 through an elongated hole 32 opened in the stroke direction of the hollow shaft 23. A coil spring 33 inserted into the hollow shaft 23 exerts its tension on the inner shaft 24, and this tension is regulated by the regulation pin 31 abutting the lower end of the elongated hole 32.

A drive device 34 is attached to the outer side of the outer cylinder 29 for forcibly retracting the magnet 22 in a direction opposite to the advancing direction of the supply rod during the forward movement of the supply rod 20 near the end of its forward stroke.
As this driving device, an electromagnetic solenoid or the like may be used, but here an air cylinder 35 is used, and a locking piece 37 fixed to the piston rod 36 is connected to a long hole 37 formed in the outer cylinder 29 in the stroke direction. It protrudes into the outer cylinder 29 through the cylindrical member 29, and faces the aforementioned restriction pin 31 so as to be able to abut against it.

As is clear from FIG. 2, the supply rod 20 (hollow shaft 23) has an oval cross-sectional shape by forming flat surfaces 39 and 40 on both sides. It is fitted into a through hole 42 formed in the hole 42 to prevent rotation. The upper plate 41 has a notch 4 for receiving the sliding body 25.
3 is provided.

The supply pipe 18 has a rectangular cross section, and has bifurcated protrusions 45 and 46 by providing a cutout 44 as shown in FIG. Opening/closing plates 49 and 50 are pivotally mounted. In short, one wing piece of the hinge is the opening/closing plate 49,
50, and the other wing piece is fixed to the projecting pieces 45, 46 with bolts 53, 54 as fixed plates 51, 52. The helical springs 55 attached to the pivots 47, 48 (only the pivot 47 side is shown in FIG. 5) give elasticity in the closing direction to the opening/closing plates 49, 50 to maintain the state shown in FIG. 4. are doing. The two-dot chain line in FIG. 5 shows the state in which the opening/closing plate 49 is pushed open.

To explain the operation of the embodiment described above, when the nut pushed by compressed air or the like moves inside the supply pipe 18 and reaches near the end of the supply pipe 18, the nut 17 is attracted by the magnet 22. and is introduced into the protrusion 21, as shown by the two-dot chain line in FIGS. 1 and 4. Next, when the supply rod 20 moves forward, the opening/closing plates 49, 50 are opened by the nut 17.
is pushed open, and the nut 17 advances while being attracted and held by the magnet 22, and comes close to the guide pin 14 of the fixed electrode, that is, near the end of the forward stroke, and in the middle of its forward movement, the air cylinder 35 is activated. When the locking piece 37 is pulled up, the displacement is transmitted to the sliding body 25 via the regulating pin 31, the inner shaft 24, and the bolt 26, and the magnet 22 (and the other magnets 28 at the same time) is pulled up by the nut 1.
7, the attractive magnetic force on the nut 17 is substantially eliminated, and the threaded hole of the nut is penetrated by the guide pin 14, completing the nut feeding.

In the embodiment shown in FIG. 7, the protrusion at the end of the supply rod is modified; in the previous embodiment, the protrusion 21 was U-shaped; however, here it has two protrusions facing each other on the outside of the nut. 56 and 57, instead, the magnet 22 closes the opening as shown in FIG. 7, and the magnet 22 closes the nut 17.
It has come to be in direct contact with

In the embodiment shown in FIG. 8, the magnet 22 is advanced and retracted by an operating rod 58 placed along the outside of the supply rod 20, and guide tubes 59 and 60 are used to ensure smooth sliding with the supply rod 20. Operating rod 58 between
has been erected. A coil spring 63 is interposed between the flange 61 of the guide cylinder 59 and the flange 62 of the supply rod, and a pin 65 fixed to the guide cylinder 59 is fitted into a groove 64 formed in the stroke direction of the supply rod 20. The tension of the coil spring 63 is received by the coil spring 63. At the stage where the entire supply rod 20 advances as one and reaches the end of the stroke, the same movement operation as described above is performed, so that the locking piece 37 forcibly moves the flange 61 back. ing. In addition, in this embodiment, the supply rod 2
0 is not provided with anything equivalent to the aforementioned protrusion 21 or magnet 28, and is merely a flat end surface.

(f) Effects According to the method of the present invention, the magnet moves forward and backward in a position that applies a suction force to the outer surface of the component, that is, in close contact with the outer surface of the supply rod. By making the magnet itself sufficiently large so that the surface area of the magnet is large enough for the component, it is possible to obtain a strong suction and holding force, so the component will not fall off due to some external force or vibration, and, Even if the speed of the supply stroke is increased, there is no need to worry about parts shifting or falling.

As the magnetic force of the magnet is increased, the magnet must be separated from the component by a considerable distance in order to substantially eliminate the magnetic force on the component. For this reason, by forcing the magnet to move backwards at an early stage, near the end of its forward stroke, while it is still advancing, the above-mentioned long separation distance can be obtained in a short time. In other words, the reverse speed of the magnet is added to the forward speed of the supply rod, which is effective in reducing time, and the attractive magnetic force disappears quickly, so the parts are always kept at a fixed location. This allows for high reliability with no supply errors. By keeping the part detached at the same point at all times, the distance between the stopping point of the supply rod and the target point, such as the guide pin of the fixed electrode, can be kept very small. Finally, special attention must be paid to the fact that the magnet is pulled back by means of a drive in a direction opposite to the direction of travel of the supply rod, thereby ensuring that the above-mentioned operation is carried out in moderation. It is what is done.

[Brief explanation of drawings]

Figures 1 to 8 show examples, and Figure 1 is a vertical side view, Figure 2 is a 2-2 sectional view of Figure 1, and Figure 3 is a sectional view taken along line 2-2 of Figure 1.
The figure is a three-dimensional view, FIG. 4 is a vertical front view, FIG. 5 is a side view of the opening/closing plate, FIG. 6 is a side view showing the external appearance of the device, FIG. 7 is a three-dimensional view, and FIG. 8 is a side view. FIG. 9 and FIG. 10 are conventional examples, and are longitudinal sectional side views, respectively. 20... Supply rod, 17... Parts, 22...
Magnet, 34... Drive device.

Claims (1)

[Claims] 1. In a device that supplies parts in close contact with the end face of the supply rod, a magnet that applies a suction force to the outer surface of the part is installed in a position protruding from the supply rod so that it can move forward and backward, and is located near the end of the forward stroke of the supply rod. A method for supplying parts, characterized in that during the forward movement, the magnet is forcibly retreated by a drive device in a direction opposite to the advancing direction of the supply rod.