JPH0664882A - Work grasping device - Google Patents

Abstract

PURPOSE:To simplify the structure and prevent a work from being dislocating from a grasping part in a state to be grasped. CONSTITUTION:A work grasping device comprises grasping parts 13 and 14 to hold a work in a nipped state, transmission mechanisms 24, 25, 35, and 38 to operate the grasping parts 13 and 14, and a drive device 36 to drive the transmission mechanisms. A spring 39 is located between the transmission mechanisms and an interlocking mechanism 30 where a dead center is present in the middle of operation is arranged to at least a part of the transmission mechanisms and the grasping parts 13 and 14 grasp a work in the dead center position of the interlocking mechanism 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work holding device for holding a work to be processed by a machine tool or the like by holding the work with a holding portion.

[0002]

2. Description of the Related Art A work gripping device used in a conventional manipulator or the like is a device for holding and moving a gripping part for holding a work by holding a predetermined position of the work by a hydraulic device or an electromagnet. there were. Here, in order to prevent the work from coming off the gripping device due to vibration,
Generally, the grip portion is formed so as to be locked at a position where the work is held. This locking means is designed to be maintained directly by an electromagnet or a hydraulic device.

[0003]

In the case of the above-mentioned conventional technique, a special member or device for locking the gripping part is required in addition to the drive device for the work gripping and opening operation of the gripping part. There was a problem that the configuration became complicated. Further, there is also a problem that when electricity does not come due to a power failure or the like, the electromagnet and the hydraulic pump also do not operate, and the work may drop from the grip portion.

The present invention has been made in view of the above-mentioned problems of the prior art, and it is an object of the present invention to provide a work gripping device having a simple structure and in which a work does not come off from a gripping portion while gripping the work. To aim.

[0005]

According to the present invention, there is provided a gripping portion for sandwiching and holding a work, a transmission mechanism for operating the gripping portion, and a drive device for driving the transmission mechanism. A work is formed with a spring interposed and at least a part of the transmission mechanism is provided with an interlocking mechanism in which a dead point exists in the operation process, and the gripper holds the work at the dead point of the interlocking mechanism. It is a gripping device.

[0006]

The work gripping device of the present invention does not move when the gripping part holds the work, no matter what force is applied from the work side, and because the interlocking mechanism is located at the dead point during a power failure. , The gripping position of the gripping part does not shift,
The grip state is reliably maintained.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 4, the work gripping device of this embodiment is used for a manipulator 11 that holds and moves the work 10, and the manipulator 11 is located before and after the gripping device 12 that grips the work 10. It comprises a pair of gripping parts 13 and 14, a rotating part 16 for changing the direction of the work 10 and a guide part 18 for moving the position of the work 10.

The gripping device 12 of this embodiment is shown in FIGS.
As shown in FIG. 3, a plurality of holding pins 20 each having a tapered tip end are provided on the work-piece 10 on the flat plate-shaped gripping portions 13 and 14.
The holding pin 20 projects toward the workpiece 10 and
It fits into the positioning hole 43 formed at a predetermined position. A sliding cylinder 21 is fixed to each of the gripping portions 13 and 14, and the sliding cylinder 21 is provided over both ends of a mounting base 22 of the work gripping device 12.
Is provided so as to be movable, and the interval between the grip portions 13 and 14 is variable.

A pair of L-shaped rocking members 24 and 25 constituting a transmission mechanism are mounted on the mounting base 22 symmetrically with respect to each other via shafts 26 and 26, respectively. A long hole 27 is formed at one end of the swing member 25, and a connection pin 28 is inserted through the long hole 27, and a connection pin 28 is also inserted through one end of the swing member 24. The tip ends of the pair of swing members 24 and 25 are swingably connected by a connection pin 28. Furthermore, this connection pin 28
One end of a toggle mechanism 30, which is an interlocking mechanism composed of two links 31 and 32, is rotatably attached to the. One ends of the links 31 and 32 are rotatably connected to each other, and the other end of the toggle mechanism 30 is connected to the shaft 3
It is rotatably supported by the mounting base portion 22 by means of 3.

The link 32 is integrally formed with an oscillating piece 34 which is integrally projected to the opposite side with the shaft 33 interposed therebetween.
The tip of the swinging piece 34 is fitted into the recess 35a of the slider 35 that is slidably provided along the mounting base 22,
The slider 35 is the push rod 3 of the hydraulic cylinder 36.
7 through a connecting member 38. One end of the connecting member 38 faces the shoulder portion 35b of the slider 35 so that it can abut, and the connecting member 38 is provided slidably from the shoulder portion 35b to the tip side. The other end of the connecting member 38 is fixed to the push rod 37. A coil-shaped spring 39 inserted into the slider 35 is provided between the tip of the slider 35 and the connecting member 38 in a compressed state. Therefore, the spring 39 biases the shoulder portion 35b of the slider 35 and the connecting member 38 in a direction in which they are always in contact with each other.

One end of a connecting member 40 is connected to the other tip of the swinging member 24, and the base end of the grip portion 13 is fixed to the connecting member 40. Further connecting member 40
A stopper member 42 is fixed to the other end of the mounting base 22, and the stopper member 42 is inserted into the side wall 22a of the mounting base 22 and is provided so as to be able to contact the outer side surface of the side wall 22a. Further, one end of the connecting member 41 is connected to the other tip of the swinging member 25, and the base end of the grip portion 14 is fixed to the connecting member 41.

The operation of the work gripping device of this embodiment will be described below. First, before holding the work 10, the gripping portions 13 and 14 are in a state in which the gaps are open, and are located at the positions indicated by the two-dot chain line in FIG. In this state, the rocking members 24 and 25 are at the positions shown by the two-dot chain line in FIG.
The toggle mechanism 30 is folded in a V shape. Here, the rocking members 24 and 25 are the long holes 27 of the rocking member 25.
Is formed so as to be swingable, and the connecting pin 28
Swings around the shaft 26 of the swinging member 24. And
The oscillating piece 34 is at the position shown by the chain double-dashed line in FIG. 1, and the push rod 37 of the slider 35 and the hydraulic cylinder 36.
Is located on the left side of the backward limit position, that is, the position shown in FIG. At this time, the slider 35 is held in the retracted position with the connecting member 38 in contact with the shoulder portion 35b of the slider 35.

Next, when the work 10 is gripped, the hydraulic cylinder 36 is operated to move the push rod 37 to the forward limit position, that is, the state shown in FIG. As a result, the slider 35 moves in the same direction from the connecting member 38 via the spring 39. Therefore, with respect to the movement of the push rod 37, the spring 39 acts as a cushioning member between itself and the slider 39, and also serves as a motion transmitting means. With the movement of the slider 35, the swinging piece 34 and the link 32 integral therewith swings counterclockwise in FIG. 1 about the shaft 33, and the links 31 and 32 are moved as shown by the solid line in FIG. , Move in the direction of straight line. Due to the movement of the links 31 and 32, the swinging member 24 is rotated clockwise and the swinging member 25 is rotated counterclockwise via the connection pin 28. As a result, the grip portion 13 moves to the left in FIG. 1 via the connecting member 40, and the stopper 4
2 comes into contact with the side wall portion 22a of the mounting base portion 22 and the grip portion 13 stops. At the same time, the grip 14 also moves to the right in FIG.
Stop with the stop of.

The position of the grip portion 13 is regulated by the stopper 42 to a position where the workpiece 10 is securely gripped, and at the stop position, the links 31 and 32 are in a linear state, and the slider 35 also stops. Therefore, the push rod 37 resists the force of the spring 39 and holds the grip portion 13 and the slider 35.
And the like move slightly more than the position stopped by the stopper 42, and in the stopped state, the connecting member 38 moves the slider 3
Stop slightly away from the shoulder 35b of No. 5.

In this state, the grips 13 and 14 securely hold the work 10 by the holding pins 20. Then, even if some force acts on the grips 13 and 14 from the side of the work 10 and the gap between the grips 13 and 14 is widened, the toggle mechanism 30 that moves the grips 13 and 14 is a dead point. It is located at a point and the links 31 and 32 do not move. That is, in order to increase the distance between the grips 13 and 14,
Although the swing member 24 must rotate counterclockwise and the swing member 25 must rotate clockwise, the toggle mechanism 30
Is located at the straight line, so link 3
1,32 are not V-shaped. Therefore, even if a force is applied to the grips 13 and 14 from the side of the work 10 while the work 10 is held, the interlocking mechanism that moves the grips 13 and 14 does not move at all, and the grips 13 and 14 do not spread. Further, in the work gripping state, the force of the hydraulic cylinder 36 causes the gripping portion 13,
Since it is not acting on 14, the hydraulic cylinder 3
Even if the pressure of 6 is released, the gripped state is maintained as it is.

When the gripping of the work 10 is released,
Contrary to the above operation, by pulling the push rod 37 by the hydraulic cylinder 36, the swinging piece 34 and the link 32 are rotated counterclockwise in FIG. It becomes a V-shape, and the swinging members 24, 25 rotate via the connecting pin 28 to widen the gap between the gripping parts 13, 14. At this time, the push rod 37 directly contacts the shoulder portion 35b of the slider 35 via the connecting member 38 and moves it to the retracted position.

According to the work gripping device of this embodiment, the toggle mechanism 30, which is the interlocking mechanism for moving the gripping parts 13 and 14 in the work gripping state, is located at a thought point, and spring force, electromagnetic force, hydraulic pressure, etc. are externally applied. The work holding state is reliably maintained without any action. In particular, even when an abnormality such as a power failure occurs, there is no influence at all, and the work gripping state is reliably maintained. Further, during the work holding operation, that is, while the hydraulic cylinder 36 moves the slider 35 via the spring 39,
When the holding pin 20 of the gripping portions 13 and 14 is not inserted into the positioning hole 43 of the work 10 and hits the end face of the work 10, the slider 35 stops at that position, but after that, the driving of the hydraulic cylinder 36 continues. To be But,
The hydraulic cylinder 36 is driven only by compressing the spring 39, and its power is not transmitted to the slider 35. Therefore, due to the inclination of the work 10
Although the holding pins 20 do not further press the end surface of the work 10 by the force of the hydraulic cylinder 36 even if the work pieces 3 and 14 cannot hold the work 10, the end surface of the work 10 may be damaged or the device may be damaged. It does not damage itself. Further, during the work gripping operation, the tip tapered portion of the holding pin 20 of the gripping portions 13 and 14 becomes the work 1.
When the slider 35 is inserted in contact with the edge of the zero positioning hole 43, the slider 35 temporarily stops. However, the hydraulic cylinder 36 continues to drive and compresses the spring 39. Then, due to the restoring force of the spring 39, the holding pin 20 is inserted into the positioning hole 43 while sliding the edge portion of the positioning hole 43 by its tapered portion. As a result, even if the work 10 is slightly displaced, the gripping operation is reliably performed while the position is smoothly corrected by the force of the spring 39.

In addition to the toggle mechanism, the interlocking mechanism of the work gripping device of the present invention may use a slider crank mechanism or a link mechanism of another shape. Further, a cam mechanism may be used as long as it has a dead point during operation.

[0019]

EFFECTS OF THE INVENTION At least a part of the work gripping device and the transmission mechanism of the present invention is provided with an interlocking mechanism having a dead point in the operation process, and the gripping part grips the work at the dead point of the interlocking mechanism. Since the work piece is formed in such a state, the grip portion does not move even if any force is applied to the grip portion at the work grip position, and the work does not come off. Moreover, since the drive mechanism operates the interlocking mechanism via the spring, if the gripping portion does not grip the predetermined position of the workpiece during the gripping operation, the spring absorbs the driving force thereafter.
A driving force greater than the biasing force of the spring does not act on the grip portion, and the grip portion can be stopped at that position. Therefore, the work and the device can be prevented from being damaged, and the safety is high. As described above, the work gripping device of the present invention does not require external power to maintain the gripped state, and can securely hold the work with a simple configuration.

[Brief description of drawings]

FIG. 1 is a partially cutaway bottom view of an embodiment of a work gripping device of the present invention.

FIG. 2 is a front view of the work gripping device of this embodiment.

FIG. 3 is a left side view of the work gripping device of this embodiment.

FIG. 4 is a front view of a manipulator provided with a work gripping device of this embodiment.

[Explanation of symbols]

 12 Work Gripping Device 13, 14 Gripping Part 24, 25 Swinging Member 30 Toggle Mechanism 35 Slider 38, 40, 41 Connecting Member 36 Hydraulic Cylinder 39 Spring

Claims (2)

[Claims] 1. A work gripping device having a gripping part for sandwiching and holding a work, a transmission mechanism for actuating the gripping part, and a drive device for driving the transmission mechanism. A spring for transmitting the driving force in the gripping operation direction and an interlocking mechanism in which at least a part of the transmission mechanism has a dead center in the operation process are provided, and the gripper holds the workpiece at the dead center position of the interlocking mechanism. A work gripping device, wherein the transmission mechanism is formed in a gripped state. 2. The work gripping device according to claim 1, wherein the interlocking mechanism is a toggle mechanism.