JPH0487737A - Method for detecting bolt chucking and device thereof - Google Patents

Abstract

PURPOSE:To detect whether a bolt is surely inserted or not with relatively simple constitution by detecting the insertion of the bolt into a bolt tightening hole in a position of a bolt retaining plate which retains a heat part of the bolt supported by a pawl piece in a lower end of a pair of chuck pawls. CONSTITUTION:When a chucking device is moved upward through a piston rod 2 after a chuck pawl 6 is actuated in a closing direction, a bolt 13 is moved downward through a bolt retaining plate 14 by pressing force of a spring 16, and a lower surface of a bolt head part 13b is engaged with an upper surface of a pawl piece 6a. In the case that the bolt is correctly held by the chuck pawl 6, the bolt retaining plate 14 is brought into contact with a top surface of the bolt head pat 13b, and a photo sensor 18, whose light beam is intercepted by a shutter part 17c, is turned off. In the case that the bolt is not held by the chuck pawl 6, the bolt retaining plate 14 is lowered further downward to lower down a shutter plate 17, and the photo sensor 18 is turned on to detect the bolt not being held.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a chucking detection method and a detection device for a bolt chucking device used in a bolt tightening machine or the like.

(Problems to be solved by conventional techniques and ideas) Generally, when installing an engine cylinder head, etc., a bolt chucking device holds a predetermined bolt and transports it from a bolt delivery position to a bolt tightening position.
Bolt tightening machines are used to automatically tighten bolts.

By the way, when supplying a bolt to a bolt tightening hole, if the chuck cannot grasp the bolt or the bolt does not fit into the bolt tightening hole, there is no bolt supplied to that hole, so the bolt The tightening will not be performed. Therefore, it is necessary to check whether the bolt has been securely gripped by the chuck device or whether the bolt has entered the bolt tightening hole.

Therefore, if it is attempted to detect whether a bolt is securely inserted into each bolt tightening hole, a large number of sensors are required, and it is difficult to support a wide variety of models.

There is also a method in which the chuck device compares whether the bolt is chucked during the bolt transport process and the return process.
In this case, it is impossible to determine whether the bolt is reliably inserted into the bolt tightening hole. Furthermore, while the chuck is moving, it may be possible to detect the bolt with a sensor fixed elsewhere, but this would result in uncertain operation and would require the chuck device to pass through the sensor, resulting in cycle time. There are problems such as waste.

In view of these points, the present invention has a relatively simple configuration.
It is an object of the present invention to provide a bolt chucking detection method and device capable of detecting whether or not a C-bolt is securely inserted.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a means for solving problems by means of claw pieces provided at the lower ends of a pair of chuck claws that open and close each other and protruding in directions opposite to each other.
In addition to supporting the tightening surface of the bolt, the head of the bolt is held down by a vertically movable bolt holding plate, and the position of the bolt holding plate is used to detect a chuck failure or the state of insertion of the bolt into the bolt tightening hole. It is characterized by the following.

Further, the second invention provides a pair of chuck claws that protrude in opposite directions at the lower ends of the pair of chuck claws that open and close each other, and engages with the tightening surface of the bolt to support the bolt. A bolt holding plate that is biased downward by a spring is movable up and down between the chuck jaws, and a shutter that controls the ON/OFF of the photoelectric sensor is attached to a guide rod that stands up from the bolt holding plate. It is characterized by the fact that

(Function) When the chucking device is lowered with the chuck jaws open, the bolt holding plate comes into contact with the bolt head held vertically on the delivery device.

Then, when the chucking device is further lowered, the bolt holding plate stops in contact with the bolt head, and the chuck claws etc. descend against the spring force. When the chucking device descends to a predetermined position in this manner, the chuck claws are closed.

When the chucking device is moved upward, the bolt is pressed down by the bolt holding plate, and the lower surface of the bolt head (the tightening surface of the bolt) engages with the claw piece, and the bolt is pulled by the claw piece to the lower surface of the bolt head. It is held vertically suspended with reference to .

By the way, if the bolt is not chucking during the above operation, the bolt holding plate will drop to the claw position, and the photoelectric sensor will be activated due to the difference in the position of the bolt holding plate, indicating that the chucking is defective. is detected. In addition, in the bolt supply device, if the bolt is not inserted into the first bolt tightening hole when the chucking device is lowered, the bolt holding plate is relatively moved upward by the bolt head, and the movement of the bolt holding plate causes the photoelectric sensor to be detected. is activated, and it is detected whether it is inserted incorrectly.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2.

Reference numeral 1 in the figure is a chuck holder, and the chuck holder 1 is attached to the lower end of a piston rod 2 of a servo motor attached to a transfer device (not shown).

The chuck holder 1 has a bolt chucking device 3.
A housing 4 is attached.

A bracket 5 is provided at the F end of the housing 4, and a pair of chuck claws 6.6 are pivotally attached to the bracket 5 so as to be swingable around the horizontal bin 7.7. A compression spring 8 is interposed between the two chuck jaws 6, 6, and the compression spring 8 biases both the chuck jaws 6, 6 in the opening direction. Incidentally, an air cylinder 9 is formed in the housing 4, and a piston 10 is mounted in the air cylinder 9 so as to be movable up and down, and the lower surface of the piston 10 is provided outside the top end of the chuck claw 6. The roller 11 is pressed against the roller 11.

Note that the reference numeral 12 in the figure is an air pipe.

At the lower ends of the pair of chuck jaws 6, 6, claw pieces 6a protruding in directions opposite to each other are integrally formed, and a recess 6b is formed at the tip of each of the claw pieces 6a. When the piece 6a is closed, that is, when the bolt is chucked, an opening is formed that is slightly larger than the diameter of the lower neck portion 13a of the bolt 13 to be chucked.

Further, between the two chuck claws 6.6, there is a bolt holding plate 1.
4 is arranged to be movable up and down. The bolt holding plate 1
4 has two guide rods 15 erected thereon, and the upper portions of the guide rods 15 are slidably inserted into and engaged with the chuck holder 1, and there is a gap between the chuck holder 1 and the bolt holding plate 14. A spring 16 is disposed to urge the bolt holding plate 14 downward. In this case, the spring 16 is designed so that the force applied to the bolt holding plate during bolt chucking becomes almost zero.

By the way, at the top end of one of the guide rods 15, there is a second
As shown in the figure and FIG. 3, a shutter plate 17 is attached. That is, the shutter plate 17 has a flat plate part 17a attached to the top end of the guide rod 15, and a bent piece 17 bent downward on the tip side of the flat plate part 17a.
b is formed, and a shutter portion 17c protrudes forward (to the left in FIG. 3) at the lower end of the bent piece 17b.
is formed.

On the other hand, the chuck holder 1 has chuck claws 6, 6.
When the bolt 13 is correctly supported and held and the bolt presser plate 14 is in contact with the bolt head, a pair of photoelectric sensors 18 are placed at positions sandwiching the shutter portion 17c.
．． 18 is attached via a bracket 19.

When grasping a predetermined bolt, the chucking device is lowered by the piston rod 2 with the chuck claws 6 opened by the compression spring 8 at the bolt delivery position. When the chucking device is lowered in this manner, the bolt holding plate 14 is attached to the top surface of the bolt head 13b of the bolt 13 held vertically on the delivery device.
comes into contact. Then, when the chucking device is further lowered, the bolt holding plate 14 stops in contact with the head of the bolt 13, and the chuck claw 6 is further lowered.

In this manner, when the chuck claw 6 is lowered to a predetermined position, compressed air is supplied into the air cylinder 9 via the air pipe 12, and the piston 10 is compressed. Therefore, the roller 11 provided on the upper part of the chuck claw 6 is pressed downward by the pressure of the piston 10, and the chuck claw 6 is swung in the closing direction, so that the recess 6b at the tip of the claw piece 6a of both chuck claws 6 is The lower neck portion 13a of the bolt 13 is inserted into the opening formed by (solid line in Figure 1).

Therefore, when the chucking device is moved upward by the piston rod 2, the bolt 13 is pressed downward by the bolt press plate 14, and the lower surface of the bolt head 13b engages with the upper surface of the chuck claw 6, and the claw piece 6a This holds the bolt 13 in a vertically suspended state with the lower surface of the bolt head 13b as a reference.

That is, when the chuck jaw 6 is operated in the closing direction and the chucking device is moved upward via the piston rod 2, the opening formed by the recess 6b at the tip of both jaw pieces 6a, 6a of the chuck jaw 6 is opened. Since the size of the lower neck portion 13a of the bolt 13 is slightly larger, the bolt 13 is easily moved downward via the bolt holding plate 14 by the pressing force of the spring 16, and the lower surface of the bolt head 13b of the bolt 13 is It is engaged with the upper surface of the claw piece 6a. Therefore, even if the lengths of the bolts are slightly different from each other, the chuck jaws always
The bolt head 13b can be supported by the claw piece 6a. Moreover, in this case, since the bolt holding plate 14 is in contact with the upper surface of the bolt head 13b, the bolt head 13b
The lower surface of the bolt is placed evenly on the surface of the claw piece 6a of the chuck claw 6 over the entire circumference, and the bolt is always held vertically.

When the bolt is correctly held by the chuck claws 6 in this manner, the bolt holding plate 14 comes into contact with the top surface of the bolt head 13b, as shown by the solid line in FIG. In this case, as shown in FIG. 5, the shutter portion 17c of the shutter plate 17 is in a position to block the light beam of the photoelectric sensor 18, and the photoelectric sensor 18 is turned off.

On the other hand, if the bolt is not held by the chuck claws 6, the bolt holding plate 14 further descends toward the claw pieces 6a, as shown in FIG. Accordingly, the shutter plate 17 is lowered via the guide rod 15,
The shutter part 17e is positioned below the light beam of the photoelectric sensor 18, and the photoelectric sensor 18 is ONL, which means that it is detected that the bolt is not held.

After the bolt is accurately gripped by the above-mentioned chucking device, the chucking device is further moved up and transported to a predetermined bolt tightening position, and when the chucking 2 position is lowered there, the lower end of the bolt 13 is Predetermined bolt hole 20 (
(Fig. 4).

However, in this case as well, the bolt holding plate 14 remains in the position MI~ as shown in FIG. Insertion is detected. Therefore, after opening the chuck claws 6 by releasing the air pressure in the air cylinder 9, the supply of bolts can be completed by moving the chucking device upward.

By the way, when the bolt is being chucked by the chuck claw 6 as described above, since the pressing force of the spring 16 is almost O, the chuck claw 6
When the chuck jaws 6 move in the opening direction, no large frictional force is generated between the jaw pieces 6a and the bolt head, and the chuck jaws 6 can be swung in the opening direction very easily.

In addition, when inserting the lower end of the bolt into the bolt hole after transporting the bolt to the bolt tightening position, the axis of the bolt hole and the axis of the bolt may be slightly misaligned, causing the bolt to hit the edge of the bolt hole. In such a case, both claw pieces 6a, 6g
Since the opening formed by the bolt is larger than the diameter of the bolt, the bolt head 13b moves the bolt holding plate 14 upward against the spring 16 in response to the lowering of the chucking device, as shown in FIG. I am made to do so.

Therefore, in this case, as shown in FIG. 9, the shutter part 17e of the shutter plate 17 moves above the mounting position of the photoelectric sensor 18, and the light beam of the photoelectric sensor 18 is no longer blocked, so that the photoelectric sensor 18 It becomes ON, and it can be detected that the bolt 13 is not inserted into the bolt hole 20.

〔Effect of the invention〕

Since the present invention is configured as described above, a chuck defect and a supply defect can be detected with a single sensor, and costs can be reduced and maintenance can be made easy. Moreover, since the bolt is directly detected, it can be detected reliably, and since the detection location is not fixed, there is no effect on cycle time.Furthermore, even if a bolt is dropped during transportation, it can be detected. .

[Brief explanation of the drawing]

Fig. 1 is a partial cross-sectional view of the bolt chucking device according to the present invention, Fig. 2 is a side view taken along line nn in Fig. 1, Fig. 3 is a front view of the chucking detection section, and Fig. 4. 9 to 9 are respectively explanatory diagrams of the operation of the present invention. 1... Chuck holder, 3... Bolt chucking device, 4... Housing, 6... Chuck claw, 6
a... Claw piece, 10... Piston, 11... Roller, 13... Bolt, 14... Bolt holding plate, 15...
...Guide rod, 16...Spring, 17...
Shutter plate, 17c... Part of the shutter, 18... Photoelectric sensor.

Claims (1)

[Claims] 1. The clamping surface of the bolt is supported by claw pieces provided at the lower ends of a pair of chuck claws that open and close mutually and protrude in directions opposite to each other, and by a vertically movable bolt holding plate. A method for detecting bolt chucking, characterized in that a defective chuck or a state of insertion of the bolt into a bolt tightening hole is detected by holding down the head of the bolt and depending on the position of the bolt holding plate. 2. The lower ends of a pair of chuck jaws that open and close each other are provided with claw pieces that protrude in opposite directions and engage with the bolt tightening surface of the bolt to support the bolt, and between the pair of chuck jaws. The present invention is characterized in that a bolt holding plate urged downward by a spring is disposed so as to be movable up and down, and a shutter for controlling ON/OFF of the photoelectric sensor is attached to a guide rod erected from the bolt holding plate. A bolt chucking detection device.