JP3548604B2 - Stud bolt direction determination method and direction determination device - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a direction discriminating method and a direction discriminating device based on the lengths of threaded portions of stud bolts having different lengths of threaded portions at both ends.
[0002]
[Prior art]
Most stud bolts having screw portions at both ends differ in the form of the screw portions at both ends, such as the length and screw pitch. When automatically supplying stud bolts with different thread forms at both ends to a bolt automatic assembling machine such as an impact wrench, etc., stud bolts that have been aligned and conveyed in the axial direction from the parts feeder are screwed on both sides of the shaft. The direction is discriminated based on the difference in the form of the parts, and the screw parts of the same form are aligned so as to face a fixed direction and are automatically supplied to an impact wrench or the like.
[0003]
As a method of determining the direction of the stud bolts that are aligned and conveyed from the parts feeder, a method of measuring the screw pitch of the thread part at both ends, and projecting light on the outer circumference of the stud bolt from a fixed direction, and using the photoelectric sensor to reflect the amount of reflected light Methods for measuring are known. In the former method, the thread pitches of the threaded portions at both ends of the stud bolt held at the fixed position are measured, and the magnitude thereof is determined to determine the direction of the stud bolt at the fixed position. The latter method uses the fact that the outer periphery of the shaft of the stud bolt has less unevenness and that the amount of reflected light from this is greater than the amount of reflected light from the threaded portion with more unevenness. Determine.
[0004]
[Problems to be solved by the invention]
The method of determining the direction of the stud bolt by measuring the thread pitches of the threaded portions at both ends of the stud bolt can relatively accurately determine the direction as long as the difference in thread pitch between the threaded portions at both ends is large. However, many types of stud bolts have a small screw pitch difference of 1 mm or less at both ends, and it is difficult to accurately detect the screw pitch. There was a problem that chipping and misjudgment often occurred. Further, the method of determining the direction of the stud bolt by measuring the screw pitch cannot be applied to stud bolts having the same thread pitch of the threaded portions at both ends, and thus has a problem of lack of versatility.
[0005]
In addition, the method of detecting the difference in the amount of reflected light from the shaft portion of the stud bolt and the outer periphery of the screw portion with a photoelectric sensor to determine the direction of the stud bolt also applies to stud bolts having the same thread pitch of the thread portions at both ends. Despite the convenience, if dust is attached to the stud bolt, the dust may cause the photoelectric sensor to malfunction. Actually, the stud bolts are sent to the direction discriminating position while being aligned by the parts feeder, and the direction is discriminated by being held at this position, but powdery dust adheres to the stud bolts while being aligned and transported by the parts feeder. However, this dust may be transferred to the eyes of the photoelectric sensor at the direction determination position, causing a decrease in the sensitivity of the photoelectric sensor, causing the photoelectric sensor to malfunction, and the direction of the stud bolt may not be accurately determined.
[0006]
An object of the present invention is to provide a method and a direction discriminating apparatus for always and reliably discriminating the direction of a stud bolt regardless of the screw pitch of the stud bolt and the presence or absence of dust.
[0007]
[Means for Solving the Problems]
The method of the present invention is a method of determining the direction of stud bolts having different lengths of a first screw portion and a second screw portion on both sides of a shaft portion based on a difference in the length of each screw portion. The stud bolts can be either in the normal direction or in the opposite direction 180 ° from the air holes at two fixed positions that approach and oppose the shaft of the stud bolt and the first or second thread. Air from the same air supply source is blown toward the shaft portion and the first screw portion or the second screw portion, and the amount of air leakage from the air hole to the shaft portion with less unevenness corresponds to the screw portion with larger unevenness. The above object is attained by judging the direction of the stud bolt at a fixed position by judging the magnitude of the air pressure of the two air holes due to the fact that the air leak amount becomes smaller than the amount of air leaking from the holes .
[0008]
The device of the present invention is a device that determines the direction of stud bolts having different lengths of the first screw portion and the second screw portion on both sides of the shaft portion based on the difference in the length of each screw portion. The bolt holding portion to be held, and the bolt holding portion are formed at two predetermined positions on the surface of the bolt holding portion which are close to and opposed to the outer periphery of the stud bolt. When one faces the shaft part of the stud bolt, the other faces the first screw part or the second screw part of the stud bolt, and blows air from the fixed direction to the shaft part and the first screw part or the second screw part, respectively. A direction discriminator having a first air hole and a second air hole, an air chamber communicating with each air hole of the direction discriminator, and an air chamber disposed in the air chamber so as to be able to reciprocate in a fixed direction. To the first air hole A movable body that divides into two into a first air compartment that passes therethrough and a second air compartment that communicates with a second air hole of the direction discriminator, and displaces the air chamber in accordance with the air pressure difference between the air compartments; A direction detector having a sensor for detecting a displacement direction; and an air supply source for supplying air of the same pressure to a first air compartment and a second air compartment of the direction detector, wherein the direction discriminator and the direction detector are separate. It is characterized by being a body .
[0009]
[Action]
When air from the same air supply source is blown from two air holes in the fixed position to the shaft of the stud bolt held at the fixed position and one of the screw parts on both sides of the shaft, it corresponds to the shaft with little unevenness The amount of air leaked from the air hole is smaller than the amount of air leaked from the air hole corresponding to the thread part with large unevenness, and the air pressure of the air hole on the shaft part is greater than the air pressure of the air hole on the screw part. When the height of the stud bolt becomes high, the direction of the stud bolt at the fixed position is determined by the magnitude of the air pressure of both air holes. The size of the air pressure of the two air holes at the fixed position can be detected accurately and accurately by moving the movable body such as the piston rod of the air cylinder with the air pressure difference between the two air holes. Performed with high reliability.
[0010]
Further, two air holes are provided at fixed positions of the direction discriminating body for holding the stud bolts at the fixed positions, and a direction detector for detecting the magnitude of the air pressure of the two air holes is provided separately from the direction discriminating body. Thus, a sensor that outputs a stud bolt direction detection signal can be installed in the direction detector, and there is no fear that the function of the sensor is impaired by the stud bolt, and the stud bolt direction determination operation of the sensor is stabilized. Further, the structure of the direction discriminator without the sensor is simplified, and a fixed type discriminator or a rotary type that reverses the direction of the stud bolt can be arbitrarily used.
[0011]
【Example】
Hereinafter, embodiments will be described with reference to the drawings.
[0012]
FIGS. 1A and 1B are cross-sectional views of a main part of a stud bolt direction discriminating apparatus. The direction discriminating apparatus shown in FIG. 1 includes a direction discriminating body 3 for holding a stud bolt 1 at a fixed position, and a direction discriminating body. A direction detector 7 for detecting the direction of the stud bolt 1 held by 3, and an air supply source 9 for supplying air 8 to the direction detector 7 and the direction discriminator 3 are provided. The stud bolt 1 has a first screw portion 1b and a second screw portion 1c integrally on both sides of a substantially central shaft portion 1a. In the drawing, the length of the first screw portion 1b is shorter than the length of the second screw portion 1c, but may be reversed.
[0013]
The direction discriminating body 3 has a bolt holding portion 4 for holding the stud bolt 1 at a fixed position, and a first air hole 2a and a second air hole 2b provided at two fixed positions of the bolt holding portion 4. The bolt holding portion 4 is a bolt insertion hole, a bolt fitting groove, a chuck, or the like for holding the stud bolt 1 at a fixed position in its length direction, for example, as shown in FIG. It comprises a discriminating hole 5 having both ends opened therethrough and a stopper 6 fixed to or detachable from one end of the discriminating hole 5. The discriminating hole 5 has an inner diameter slightly larger than the outer diameter of the stud bolt 1 and is substantially the same length as the entire length of the stud bolt 1. The stud bolt 1 inserted into the discrimination hole 5 from the opening opposite to the stopper 6 of the discrimination hole 5 has its tip abutted on the stopper 6 and is held at a fixed position in the discrimination hole 5.
[0014]
Note that, as shown in FIG. 1A, the direction when the stud bolt 1 is inserted into the discriminating hole 5 with the first screw portion 1b at the top is, for example, the forward direction, and as shown in FIG. The direction when the second screw portion 1c is inserted at the head is the reverse direction. The direction discriminating body 3 is a movable type such as rotating as shown in FIGS. 3 and 4, or a fixed type as shown in FIG. 5, and its use will be described later.
[0015]
A first air hole 2a and a second air hole 2b are formed at two places on the inner peripheral surface of the determination hole 5. As shown in FIG. 1A, when the stud bolt 1 held in the discriminating hole 5 is in the forward direction, the first air hole 2a is located at a fixed position approaching and facing the shaft portion 1a of the stud bolt 1. The air hole 2b is formed at a fixed location approaching and facing the second screw portion 1c of the stud bolt 1. Also, as shown in FIG. 1B, when the stud bolt 1 held in the discrimination hole 5 is in the opposite direction, the first air hole 2a is located at a fixed position close to and opposed to the second screw portion 1c of the stud bolt 1. The second air hole 2b is formed at a fixed position approaching and facing the shaft portion 1a of the stud bolt 1.
[0016]
The direction detector 7 detects the forward / reverse direction of the stud bolt 1 held by the direction discriminator 3 based on a difference in air pressure between the air holes 2a and 2b, and an air chamber communicating with the air holes 2a and 2b. An air cylinder 11 having, for example, 10, a movable piston 12 disposed in the air chamber 10, and a sensor 14 for detecting a displacement direction of the piston 12 are provided. The air chamber 10 of the air cylinder 11 is divided into a first air compartment 10a and a second air compartment 10b by a piston 12, and the first air compartment 10a and the first air hole 2a of the direction discriminator 3 are connected by piping. The 2 air branch 10b and the second air hole 2b of the direction discriminator 3 are connected by piping. The piston rod 13 integral with the piston 12 penetrates the side walls of the air compartments 10a and 10b so as to be movable in the axial direction.
[0017]
A constant-pressure air 8 is supplied from a common air supply source 9 to both of the air compartments 10a and 10b of the air cylinder 11. The piston rod 13 is displaced by the air pressure difference between the air compartments 10a and 10b, and the direction of this displacement is detected by the sensor 14. The sensor 14 is disposed at a fixed position so as to detect the presence or absence of the piston rod 13 protruding from the second air branch 10b by a photoelectric sensor, a proximity switch, or the like.
[0018]
The direction determination of the stud bolt 1 by the direction determination device of FIG. 1 is performed as follows.
[0019]
When one stud bolt 1 is automatically supplied to the discriminating hole 5 of the direction discriminating body 3 from the outside by a parts feeder or the like, the direction of the constant-pressure air 8 from the air supply source 9 is passed through the respective air compartments 10a and 10b of the air cylinder 11. It is supplied to each air hole 2a, 2b of the body 3.
[0020]
When the stud bolt 1 is in the forward direction in the discriminating hole 5 of the direction discriminating body 3 as shown in FIG. 1A, air 8 is blown from the first air hole 2a to the shaft portion 1a of the stud bolt 1. Air 8 is blown from the second air hole 2b to the 2 screw portion 1c. Since the outer periphery of the shaft portion 1a is a surface with little unevenness, the amount of leakage of the air 8 blown from the first air hole 2a is small, and the outer periphery of the other second screw portion 1c is an uneven surface of the crests and valleys of the screw. Therefore, the air 8 blown from the second air hole 2b leaks a large amount. Therefore, the air pressure of the first air hole 2a becomes larger than the air pressure of the second air hole 2b, and the piston 12 of the air cylinder 11 moves in the direction of the second air sub-chamber 10b where the air pressure is small due to the difference between the two air pressures. . A sensor 14 is arranged at the tip of the moved piston rod 13, and the sensor 14 detects the piston rod 13 and outputs a rod presence detection signal to a direction discriminating circuit (not shown). The direction discriminating circuit detects that the rod portion detection signal from the sensor 14 indicates that the shaft portion 1a of the stud bolt 1 in the direction discriminating body 3 is in the direction of the first air hole 2a and the stud bolt 1 is in the forward direction. Is determined.
[0021]
When the stud bolt 1 is located in the opposite direction in the discriminating hole 5 of the direction discriminating body 3 as shown in FIG. 1B, the air 8 is supplied from the first air hole 2a to the second screw portion 1c of the stud bolt 1. The air 8 is blown from the second air hole 2b to the shaft portion 1a. In this case, the amount of air 8 blown from the first air hole 2a is large, and the amount of air 8 blown from the second air hole 2b is small. It becomes smaller than the air pressure of the air hole 2b. Therefore, the piston 12 of the air cylinder 11 moves in the direction of the first air compartment 10a having a small air pressure, the tip of the piston rod 13 is separated from the sensor 14, and the sensor 14 detects that there is no rod. The direction determination circuit determines that the shaft portion 1a of the stud bolt 1 in the direction determination body 3 is in the direction of the second air hole 2b and the stud bolt 1 is in the opposite direction based on the rod absence detection signal.
[0022]
Even if the air pressure difference between the air holes 2a and 2b for determining the direction of the stud bolt 1 in the direction determination body 3 is small, this air pressure difference clearly appears due to the displacement of the piston 12 of the air cylinder 11, and the air pressure difference Is amplified by the displacement of the piston 12, so that the direction of the stud bolt 1 can be accurately and reliably determined. Further, since the air 8 is blown to the direction discriminating body 3, even if dust is attached to the stud bolt 1, the dust is blown off by blowing the air 8, thereby preventing malfunction due to the dust.
[0023]
Further, since the sensor 14 for detecting the direction of the stud bolt 1 is installed at a fixed position of the direction detector 7 which is separate from the direction discriminating body 3 holding the stud bolt 1, the sensor 14 does not generate dust. Since the sensor 14 can be placed in a stable environment, the sensitivity of the sensor 14 can be stabilized, and a highly accurate direction determination operation can be performed. Further, since the direction discriminator 3 and the direction detector 7 are separately connected to each other and connected to a pipe, there is a convenience that the direction discriminator 3 can be applied to both a movable type and a fixed type.
[0024]
The embodiment shown in FIG. 2 uses a diaphragm 15 for the direction detector 7. The diaphragm 15 divides the inside of one container into a first air compartment 10a and a second air compartment 10b by a movable diaphragm 16. The first air compartment 10a communicates with the first air hole 2a, the second air compartment 10b communicates with the second air hole 2b, and air 8 at a constant pressure is supplied from the air supply source 9 to each of the air compartments 10a and 10b. You. A piston rod 17 fixed to the center of the diaphragm 16 penetrates the side wall of the second air compartment 10b and protrudes to the outside, and the sensor 14 is fixedly arranged in the movement range of the tip.
[0025]
When the stud bolt 1 inserted into the discriminating hole 5 of the direction discriminating body 3 is in the forward direction, the air pressure of the first air hole 2a and the first air compartment 10a is increased by the air pressure of the second air hole 2b and the second air compartment 10b. As the diaphragm becomes larger, the diaphragm 16 of the diaphragm 15 expands toward the second air chamber 10b, the tip of the piston rod 17 is detected by the sensor 14, and it is determined that the stud bolt 1 is in the forward direction. When the stud bolt 1 held in the discriminating hole 5 is in the opposite direction, the air pressure in the first air compartment 10a of the diaphragm 15 becomes smaller than the air pressure in the second air compartment 10b, and the diaphragm 16 becomes as shown by the chain line in FIG. Then, the tip of the piston rod 17 comes off the sensor 14 and the stud bolt 1 is determined to be in the opposite direction.
[0026]
Next, a specific application example of the direction discriminating apparatus will be described with reference to FIGS.
[0027]
In the direction discriminating apparatus shown in FIG. 3, the movable direction discriminating body 3 is arranged on a bolt conveying path 22 between the parts feeder 20 and the automatic bolting machine 21. The stud bolts 1 are arranged in a line in the axial direction in the bolt conveying path 22, and the direction discriminating body 3 can rotate forward and backward by 90 ° in a cylindrical housing 23 fixed to a substantially horizontal part of the bolt conveying path 22. Placed in The housing 23 has a bolt supply hole 24 connected to the parts feeder 20 on the side and a bolt discharge hole 25 connected to the automatic bolt assembly machine 21 below.
[0028]
One stud bolt 1 sent from the parts feeder 20 is supplied to the discrimination hole 5 with one end opening of the discrimination hole 5 of the direction discrimination body 3 aligned with the bolt supply hole 24. At this time, the portion of the housing 23 facing the bolt supply hole 24 functions as a stopper for holding the stud bolt 1 at a fixed position of the discrimination hole 5.
[0029]
When the stud bolt 1 in the discriminating hole 5 is determined to be in the forward direction, the direction discriminating body 3 rotates 90 ° in the positive direction of the solid line arrow in FIG. 25 is dropped by its own weight and supplied to the automatic bolt assembling machine 21. When the stud bolt 1 in the discriminating hole 5 is determined to be in the reverse direction, the direction discriminating body 3 rotates 90 ° in the direction opposite to the dashed arrow in FIG. As a result, the bolt 25 is dropped by its own weight and supplied to the automatic bolt assembling machine 21.
[0030]
The direction discriminating apparatus shown in FIG. 4 is configured such that the movable direction discriminating member 3 is set at 180 ° in a housing 26 fixedly disposed on a substantially vertical part of a bolt conveying path 22 between the parts feeder 20 and the automatic bolting machine 21. It is arranged to be able to rotate forward and backward. The housing 26 has a bolt supply hole 27 and a bolt discharge hole 28 at upper and lower opposing portions.
[0031]
With the upper end opening of the discrimination hole 5 of the direction discrimination body 3 aligned with the bolt supply hole 27, one stud bolt 1 sent from the parts feeder 20 is supplied to the discrimination hole 5 and fixed by the stopper 6. Held in position. When the stud bolt 1 in the discriminating hole 5 is determined to be in the forward direction, the direction discriminating body 3 does not rotate and only the stopper 6 opens, and the positive direction stud bolt 1 in the discriminating hole 5 becomes the bolt discharging hole. 28 is dropped by its own weight and supplied to the automatic bolt assembling machine 21. When the stud bolt 1 in the discriminating hole 5 is determined to be in the reverse direction, the direction discriminating body 3 is rotated by 180 °, and the stud bolt 1 in the discriminating hole 5 is turned in the forward direction, so that the bolt discharging hole 28 is self-weighted. It falls and is supplied to the bolt automatic assembling machine 21.
[0032]
The direction discriminating apparatus shown in FIG. 5 has a fixed direction discriminating body 3 disposed substantially vertically in a bolt conveying path 22 between a parts feeder 20 and an automatic bolt assembling machine 21 and a bolt direction reversing device 30 directly below the fixed direction discriminating body 3. are doing. The bolt direction reversing device 30 includes a movable reversing plate 31, a reversing block 32, and a reversing space 33 disposed in the middle of a bolt conveyance path 22 ′ provided below the discrimination hole 5 in the vertical direction of the fixed direction discrimination body 3. Having.
[0033]
In the apparatus shown in FIG. 5, when the stud bolt 1 in the discriminating hole 5 of the fixed direction discriminating body 3 is determined to be in the forward direction, the reversing plate 31 is disengaged from the bolt conveying path 22 'and the stopper 6 at the lower end of the discriminating hole 5 is provided. Is opened, the forward stud bolt 1 falls on the bolt conveying path 22 ′ by its own weight, and is supplied to the automatic bolt assembling machine 21. When the stud bolt 1 in the discriminating hole 5 of the fixed type discriminating body 3 is determined to be in the opposite direction, the stopper 6 is opened with the reversing plate 31 protruding into the bolt conveying path 22 ′, and the discrimination hole 5 causes the stopper 6 to open. The tip of the falling backward stud bolt 1 hits the reversing plate 31 and falls down to the reversing space 33 with the reversing plate 31 as a fulcrum. The stud bolt 1 that has fallen into the reversing space 33 is guided by the reversing block 32 to be reversed in the forward direction as shown by a chain line in FIG. 5, falls directly onto the bolt transport path 22 ′, and is supplied to the automatic bolting machine 21. Is done.
[0034]
【The invention's effect】
As in the method of the present invention, when air from the same air supply source is blown from two air holes at a fixed position to one of the shaft portion of the stud bolt held at a fixed position and one of the screw portions on both sides of the shaft portion, the shaft portion and Due to the difference in the amount of air leaking from the screw part, the air pressure of the air hole on the shaft part becomes higher than the air pressure of the air hole on the screw part. The direction of the stud bolt is accurately determined, and the magnitude of the air pressure of the two air holes at the fixed position is determined by moving the movable body such as the piston rod of the air cylinder by the air pressure difference between the two air holes. As a result, the stud bolt direction can be reliably detected, and the stud bolt direction determination accuracy is high and stable.
[0035]
In addition, by providing a separate direction detector for holding the stud bolt at a fixed position and a direction detector for detecting the magnitude of the air pressure of the two air holes of the direction detector, the direction detection signal of the stud bolt can be obtained. The output sensor is installed on the direction detector side in a stable environment free from dust generation, so that the function of the sensor is stabilized and the reliability of discriminating the direction of the stud bolt is improved. In addition, the direction discriminator only needs to be provided with an air hole, and it is easy to use a fixed type discriminator or a rotary type that reverses the direction of the stud bolt. A determination device can be provided.
[Brief description of the drawings]
FIGS. 1A and 1B are cross-sectional views of a main part of a stud bolt direction determining device according to a first embodiment of the present invention.
FIG. 2 is a sectional view of a main part of a stud bolt direction discriminating apparatus according to a second embodiment of the present invention.
FIG. 3 is a front view of a main part schematically showing a first stud bolt automatic alignment and supply mechanism using the apparatus shown in FIG. 1 or 2;
FIG. 4 is a front view of an essential part schematically showing a second automatic stud bolt aligning and feeding mechanism using the apparatus shown in FIG. 1 or FIG. 2;
FIG. 5 is a front view of a main part schematically showing a third stud bolt automatic alignment supply mechanism using the apparatus shown in FIG. 1 or 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Stud bolt 1a Shaft part 1b 1st screw part 1c 2nd screw part 2a 1st air hole 2b 2nd air hole 3 Direction discriminator 4 Bolt holding part 7 Direction detector 8 Air 9 Air supply source 10 Air chamber 10a First Air compartment 10b Second air compartment 12 Movable body (piston)
14 Sensor 16 Movable body (diaphragm diaphragm)

Claims (2)

A method of determining the direction of stud bolts having different lengths of the first screw portion and the second screw portion on both sides of the shaft portion based on the difference in the length of each screw portion,
Regardless of whether the direction of the stud bolt supplied to the fixed position is the forward direction or the opposite direction opposite to 180 °, the shaft portion of the stud bolt is closely approached to the first screw portion or the second screw portion, respectively. Air from the same air supply source is blown from the two air holes toward the corresponding shaft part and the first or second screw part, and the amount of air leakage from the air hole to the shaft part with less unevenness is uneven. The feature is to determine the direction of stud bolt at a fixed position by judging the magnitude of the air pressure of two air holes due to less than the amount of air leakage from the air hole corresponding to the large screw part Stud bolt direction determination method. A device that determines the direction of stud bolts having different lengths of the first screw portion and the second screw portion on both sides of the shaft portion based on the difference in the length of each screw portion.
A bolt holding portion for holding a stud bolt at a fixed position, and formed at predetermined two places on a surface of the bolt holding portion which is close to and opposed to the outer periphery of the stud bolt, and the stud bolt direction is a forward direction or a reverse direction opposite to 180 °. In either case, when one faces the shaft portion of the stud bolt, the other faces the first thread portion or the second thread portion of the stud bolt, and the other faces the shaft portion and the first thread portion or the second thread portion, respectively. A direction discriminator having a first air hole and a second air hole for blowing air from a fixed direction,
An air chamber communicating with each air hole of the direction discriminator, and a first air compartment and a direction discriminator arranged in the air chamber so as to be able to reciprocate in a fixed direction and communicating the air chamber with the first air hole of the direction discriminator. A movable body that divides into two second air compartments communicating with the second air holes and displaces the air chambers according to the air pressure difference between the air compartments, and a sensor that detects a displacement direction of the movable body. Vessels,
An air supply source for supplying air of the same pressure to the first air compartment and the second air compartment of the direction detector;
A stud bolt direction discriminating device comprising: a direction discriminating body and a direction detector .

Images