JP2964623B2 - Bolt supply control method for bolt tightening machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a bolt supply control method in a bolt tightening machine.

(Problems to be Solved by the Related Art and the Invention) Generally, when mounting a cylinder head or the like of an engine, a predetermined bolt is held by a bolt chucking device, and is conveyed from a bolt delivery position to a bolt tightening position. Automatic tightening of bolts is performed by a tightening machine.

By the way, when a bolt is supplied to the bolt tightening hole, sometimes a different bolt is mixed in the standard bolt, and if the difference in the length of the bolt is ignored, the work may be damaged or Failures such as a bolt not reaching the bolt tightening hole or a small screw-in depth may occur. In addition, if the bolt is not gripped by the chuck or if the bolt does not enter the bolt tightening hole, the work may be defective due to one-sided tightening.

Therefore, when the machine is stopped every time when the bolt of the above-mentioned chuck is missed, etc., the operator has to insert the remaining bolts into the bolt tightening holes, and the work takes a long time. There is.

In view of the foregoing, an object of the present invention is to provide a bolt supply control method capable of shortening a machine stoppage time due to an incorrectly inserted or defective bolt and preventing occurrence of a workpiece processing defect due to a poor bolt tightening. And

[Configuration of the invention]

(Means for Solving the Problems) The present invention relates to a bolt supply control method for a bolt tightening machine having a bolt length detecting device and a bolt chucking device, the method comprising: When it is detected that the insertion failure of the bolt into the tightening hole has occurred a plurality of times in succession, the supply of the bolt, the operation of the bolt chucking device is stopped, or the bolt is inserted into the tightening hole. Is stopped.

(Operation) When a bolt length defect or a bolt chucking defect is detected, the length of the next bolt is measured or chucking is performed again. Then, when the failure is detected, the supply of bolts is stopped, so that the number of stoppages of the machine and the like can be reduced, and the manual work of the operator can be reduced.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a plan view showing the general outline of the bolt tightening device, FIG. 2 is a front view of the same, and FIG. 3 is a side view thereof. Such a work 2 is placed at a predetermined position. On the other hand, a part feeder 3 is provided on one side of the bolt mounting position A, and a bolt transfer device 4 is provided at the tip of the part feeder 3.

A bolt supply robot 5 is provided above the bolt mounting position A. A bolt chucking device 6 is mounted on the bolt supply robot 5 so as to be able to move back and forth and right and left in a horizontal plane along guides 7 and 8.

An air cylinder 9 is mounted on the bolt supply robot 5 (FIG. 2), and a chuck holder 11 is attached to a lower end of a piston rod 10 of the air cylinder 9.

A housing 14 of the bolt chucking device 6 is mounted on the chuck holder 11.

A bracket 15 is provided at a lower end of the housing 14, and a pair of chuck claws 16, 16 are pivotally mounted on the bracket 15 so as to be slidable about horizontal pins 17, 17.
A compression spring 18 is interposed between the chuck claws 16, 16, and the compression spring 18 urges the chuck claws 16, 16 in the opening direction. An air cylinder 19 is formed in the housing 14, and a piston 20 is mounted in the air cylinder 19 so as to be vertically movable, and a lower surface of the piston 20 is provided outside a top end of the chuck pawl 16. Roller 21. Note that reference numeral 22 in the figure denotes an air pipe.

At the lower ends of the pair of chuck jaws 16, 16, nail pieces 16a protruding in directions facing each other are integrally formed, and a concave portion 16b is formed at the tip of each nail piece 16a. When the piece 16a is closed, that is, at the time of bolt chucking, an opening slightly larger than the diameter of the neck lower portion 23a of the bolt 23 to be chucked is formed.

Also, a bolt holding plate 2 is provided between the chuck jaws 16 and 16.
4 is arranged to be able to move up and down. The bolt holding plate 24
Has two guide rods 25 standing upright, and the upper portions of the guide rods 25 are slidably inserted into and engaged with the chuck holder 11, and the guide holder 25 is provided between the chuck holder 11 and the bolt holding plate 24. A spring 26 for urging the bolt holding plate 24 downward is provided. In this case, the spring 26 is configured so that the force applied to the bolt holding plate at the time of bolt chucking becomes almost zero.

By the way, at the top end of one guide rod 25,
As shown in FIG. 6 and FIG. 6, a shutter plate 27 is mounted. That is, the shutter plate 27 has a flat plate portion 27a attached to the top end of the guide rod 25, and the flat plate portion 27a
A bent piece 27b bent downward is formed on one end of the
At the lower end of the bent piece 27b, there is formed a shutter portion 27c projecting forward (to the left in FIG. 6).

On the other hand, the chuck jaws 16, 1
In a state where the bolt 23 is correctly supported and held by 6 and the bolt holding plate 24 is in contact with the bolt head, a pair of photoelectric sensors 28 and 28 are mounted via the bracket 29 at positions sandwiching the shutter portion 27c. I have.

On the other hand, the bolt transfer device 4 can be advanced and retracted by a cylinder device 30 in a direction orthogonal to the axis of the parts feeder 3. The bolt transfer device 4 has a bolt head at a position facing the parts feeder 3 in the drawing-in device. Notch for receiving bolts
4a is provided (FIG. 7).

At a position radially separated from the bolts supported by the bolt transfer device 4 at the advanced position, a plurality of bolt length confirmation sensors 31a, 31b, as shown in FIG. … Is arranged.

Further, a bolt protruding device 32 is provided below the bolt 23 supported by the bolt transfer device 4 at the advanced position.

When the work 2 such as a cylinder head is mounted and fixed at a predetermined position on the jig 1, a bolt 23 is supplied from the parts feeder 3 to the bolt transfer device 4, and the head of the bolt 23 is cut off for receiving the bolt. It is engaged with the notch 4a and is held in a vertical state. Then, the bolt transfer device 4 is advanced to the bolt length confirmation position, and whether or not the bolt has a predetermined length is confirmed by the bolt length confirmation sensors 31a, 31b and the like.

When the above confirmation is completed, the bolt protruding device 32 is operated,
The bolt 23 is lifted upward by a predetermined amount, and the bolt chucking device 6 is moved above the bolt to pick up the confirmed bolt.

In this case, if a different bolt is mixed in the standard bolt, and the bolt that happens to be taken out at the bolt length confirmation position is not of a predetermined length, the bolt is gripped by the bolt chucking device 6. Discarded in bolt basket. Such an operation is repeated three times. If the bolt is not of the predetermined length, the operation of the parts feeder 2 is stopped because the bolt is different, and the bolt is replaced.

On the other hand, when it is confirmed that the length of the bolt 23 is a predetermined length, the bolt 23 is gripped by the chucking device 6 and transferred to a predetermined position. That is, the chucking device 6 is lowered by the piston rod 10 with the chuck pawl 16 opened by the compression spring 18 toward the bolt pushed up by the predetermined amount by the bolt protruding device 32. When the chucking device is lowered in this manner, the bolt holding plate 24 comes into contact with the top surface of the bolt head 23b of the bolt 23 held vertically on the bolt transfer device. Then, when the chucking device is further lowered, the bolt holding plate 24 stops in a state of contact with the head of the bolt 23, and the chuck pawl 16 is further lowered.

Thus, when the chuck pawl 16 is lowered to the predetermined position, compressed air is supplied into the air cylinder 19 through the air pipe 22, and the piston 20 is lowered. Therefore,
The roller 21 provided above the chuck pawl 16 is pressed downward by the pressure of the piston 20, and the chuck pawl 16 swings in the closing direction, and is formed by the concave portion 16b at the tip of the pawl piece 16a of both chuck pawls 16. The lower part 23a of the bolt 23 in the opening
Is inserted (solid line in FIG. 4).

Then, when the chucking device is moved upward by the piston rod 10, the bolt 23 is pressed downward by the bolt holding plate 24, and the lower surface of the bolt head 23b is engaged with the upper surface of the chuck claw 16, and the claw piece 16a is used. The bolt 23 is held in a state of being suspended vertically with reference to the lower surface of the bolt head 23b.

That is, when the chucking device is moved upward through the piston rod 10 after the chuck pawl 16 is operated in the closing direction,
Since the opening formed by the concave portion 16b at the tip of both claw pieces 16a, 16a of the chuck claw 16 is slightly larger than the size of the neck lower part 23a of the bolt 23, the bolt pressing plate 24 is pressed by the spring 26 to apply the pressure. The bolt 23 is easily moved downward via the bolt 23, and the lower surface of the bolt head 23b of the bolt 23 is engaged with the upper surface of the claw piece 16a. Therefore, even when the bolts have slightly different lengths, the bolt head 23b can always be supported by the pawl pieces 16a of the chuck pawls 16. Moreover, in this case, since the bolt holding plate 24 is in contact with the upper surface of the bolt head 23b, the lower surface of the bolt head 23b is evenly placed on the surface of the claw piece 16a of the chuck claw 16 over the entire circumference. The bolt will always be held vertically.

When the bolt is properly held by the chuck pawl 16 as described above, the bolt holding plate 24 comes into contact with the top surface of the bolt head 23b as shown by the solid line in FIG.
In this case, as shown in FIG. 10, the shutter portion 27c of the shutter plate 27 is at a position where the light beam of the photoelectric sensor 28 is blocked, and the photoelectric sensor 28 is OFF.

On the other hand, when the bolt is not held by the chuck pawl 16, the bolt holding plate 24 further descends toward the pawl piece 16a as shown in FIG. Accordingly, the shutter plate 27 descends via the guide rod 25 accordingly, the shutter portion 17c is positioned below the light beam of the photoelectric sensor 28, the photoelectric sensor 28 is turned on, and it is detected that the bolt is not held. .

If such a bolt cannot be held, this operation is repeated up to three times. If the bolt cannot be held even by these three operations, it is considered that the chucking device 6 is defective. So the machine is automatically stopped,
Check the chucking device 6 and the like.

When the bolt is accurately grasped by the above-described chucking device, the chucking device is further moved up and transported to a predetermined bolt tightening position, where the chucking device is lowered. Is the specified bolt hole
33 (FIG. 9).

In this case, too, the bolt holding plate 24 is located as shown in FIG.
Are still blocked, thereby detecting that the bolt has been correctly inserted into the bolt hole 33. Therefore, after releasing the air pressure in the air cylinder 19 to open the chuck pawl 16, the supply of the bolt can be terminated by moving the chucking device upward.

By the way, in the state where the bolt is being chucked by the chuck pawl 16 as described above, the pressing force of the spring 26 is set to almost zero, so that the chuck pawl 16
During the movement of the chuck claw 16 in the opening direction, a large frictional force is not generated between the claw piece 16a and the bolt head, and the swing of the chuck claw 16 in the opening direction can be performed very easily.

In addition, when the bolt is conveyed to the bolt tightening position and the lower end of the bolt is inserted into the bolt hole, the axis of the bolt hole is slightly misaligned with the axis of the bolt, and the bolt hits the edge of the bolt hole. In such cases, both claw pieces 16a, 16
Since the opening formed by a is larger than the diameter of the bolt, the bolt holding plate 24 is raised against the spring 26 by the bolt head 23b in response to the lowering of the chucking device as shown in FIG. Be moved.

Accordingly, in this case, as shown in FIG. 14, the shutter portion 27c of the shutter plate 27 moves above the position where the photoelectric sensor 28 is mounted, the light beam of the photoelectric sensor 28 is not blocked, and the photoelectric sensor 28 is turned on. Thus, it can be detected that the bolt 23 has not been inserted into the bolt hole 33.

When the bolt 23 is not inserted into the bolt 33 as described above, the bolt that has not been inserted is thrown away into the bolt basket by the chucking device 6 each time, and the bolt is not inserted by repeating the above three times. Then, the bolt is inserted into the corresponding bolt hole, and the bolt is supplied to the next bolt hole.

When the supply of bolts to bolt holes other than the passed bolt holes is completed, the jig 1 does not shift, and a stop signal is output at that position. Therefore, the operator manually inserts the bolt into the bolt hole where the supply of the bolt was not performed,
When the track button is pressed again, the jig 1 is shifted, and the bolt is tightened by the bolt tightening unit 34.

In this way, the number of bolts to be manually inserted is reduced, and the tightening can be completed by one-button operation after the bolts are manually inserted.

〔The invention's effect〕

As described above, according to the present invention, when it is detected that a bolt length defect, a bolt chucking defect, or a bolt insertion defect into a tightening hole has occurred consecutively a plurality of times, the failure is detected. Correspondingly, the supply of bolts, the operation of the bolt chucking device was stopped, or the supply of bolts into the tightening holes was stopped. The machine stop period can be greatly reduced as compared with the stop. In addition, it is possible to reduce the number of manual operations performed by the worker when the supply of the bolt is defective, and to prevent the occurrence of a defective work due to one-side tightening or damage of the bolt.

[Brief description of the drawings]

FIG. 1 is a plan view showing an overall outline of a bolt tightening device, and FIG.
FIG. 3 is a front view of the same, FIG. 3 is a side view thereof, FIG. 4 is a partial longitudinal sectional view of a bolt chucking device according to the present invention, and FIG.
Fig. 4 is a side view taken along the line V-V in Fig. 4, Fig. 6 is a front view of a chucking detector, Fig. 7 is a plan view of a bolt transfer device, and Fig. 8 is a side view of a bolt length confirmation center. Figure, ninth
FIG. 14 to FIG. 14 are explanatory diagrams of the operation of the present invention. 1 ... Jig, 2 ... Work, 3 ... Parts feeder, 4
... bolt transfer device, 6 ... bolt chucking device, 11 ... chuck holder, 14 ... housing, 16 ...
... Chuck jaw, 16a ... Claw piece, 21 ... Roller, 23 ... Bolt, 24 ... Bolt presser plate, 25 ... Guide rod, 27 ...
… Shutter plate, 27c… Shutter section, 28… Photoelectric sensor, 31a, 31b… Bolt length confirmation sensor, 32 …… Bolt protruding device.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-77417 (JP, A) JP-A-60-228038 (JP, A) JP-A-49-50597 (JP, A) 39839 (JP, A) Japanese Utility Model Showa 55-165734 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B23P 19/06 B23P 19/00 301

Claims (1)

(57) [Claims] In a bolt supply control method for a bolt tightening machine having a bolt length detecting device and a bolt chucking device, a bolt length defect, a bolt chucking defect, or a failure in a bolt tightening hole. When it is detected that the insertion failure occurs consecutively a plurality of times, the supply of the bolt, the operation of the bolt chucking device, or the supply of the bolt into the tightening hole is stopped correspondingly. A bolt supply control method for a bolt tightening machine, characterized in that: