JPH05269689A - Work holding device - Google Patents

Abstract

PURPOSE:To improve the rate of operation in an assembling line by providing a holding device which can properly hold even a work supplied with low accuracy, by adding the degree of freedom to a holding part in a simple structure. CONSTITUTION:A work holding device comprises a holding part 2 (vacuum pad or holding click) for holding and releasing a work 1, a linear guide 4 disposed between the holding part 2 and the main body 3 for slidably supporting the holding part on the main body and a lock means 5 for fixing and releasing the holding part to and from the main body. Further, the device comprises a rotary actuator for rotating the holding part 2 relatively to the main body 3.

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, and more particularly to a work holding device which prevents a chuck error when holding or releasing a work by giving a floating function to a holding portion.

[0002]

2. Description of the Related Art In an assembly line of various devices, for example, a component carried into a line side is gripped and set at a predetermined position on the line, or a work on a line after a predetermined processing is gripped. A work gripping device is used to carry the work out of the line. A conventional work gripping device has a main body fixed to the tip of an arm of a robot and a gripping part attached to the main body, and the main body moves along with an arm that moves according to a pre-taught trajectory. The work is gripped by approaching the work and operating the gripping portion in this state. For example, when gripping a work carried in to the line side and setting it on the line, since a predetermined number of work parts are collectively carried in a supply pallet or the like, the gripping device First, the parts are grasped by approaching the supply pallet, and then the robot arm is operated to move the main body to the line.

[0003]

However, in the conventional work gripping device, since the gripping portion is fixed to the main body of the gripping device, the positional accuracy of the work to be gripped is insufficient. There was a problem that the work could not be gripped. Therefore, in order to prevent such a chuck error, it is necessary to increase the accuracy of the alignment state of the works on the supply pallet (about ± 0.05 mm) or to add the degree of freedom of movement to the works to the gripping device. ..

However, since the work is accommodated in the distribution pallet having poor alignment accuracy and carried into the line side, in order to improve the alignment accuracy of the supply pallet, the work is provided with the alignment accuracy required from the distribution pallet. Need to be transferred to another supply pallet. Therefore, there has been a problem that the cost required for the pallet is increased or extra work is increased. Further, an RCC (remote center compliance) mechanism has been conventionally known as a means for adding a degree of freedom of movement with respect to a work, a so-called compliance (following function), to a gripping device.
Since this mechanism requires elastic force, there is a problem in that the gripping part does not become in an unloaded state and an extra force acts on the work. Moreover, since such an RCC mechanism is large, there is a problem in that it is restricted in space when it is mounted on the arm of a robot.

Further, in the conventional RCC mechanism, since a degree of freedom is added in all directions on the XY plane on which the work is placed, even if it is convenient to grip the work, on the contrary, There was a problem that it was difficult to control the position of the work. For example, when gripping a work, the gripping part needs some compliance, but when mounting the gripped work on a line, especially when sufficient stopping accuracy can be ensured on the arm side of the robot, etc. ,
If the gripping part is compliant, there is a problem that the stop position of the work cannot be set and the work cannot be set at a predetermined position.

The present invention has been made in view of the above problems of the prior art, and by adding a degree of freedom to the gripping portion with a simple structure, it is appropriate even for a workpiece supplied in a low precision state. An object of the present invention is to provide a gripping device that can be gripped at any time and improve the operating rate of the assembly line.

[0007]

In order to achieve the above object, a work gripping device of the present invention comprises a gripping part for gripping and releasing a work, and a gripping part provided between the gripping part and the main body. It is characterized by having a linear guide slidably supported with respect to the main body, and locking means for fixing and releasing the grip portion with respect to the main body. It is preferable to provide rotation means for rotating the grip portion relative to the main body.

[0008]

First, the gripping device main body is brought close to the work, and the work is gripped by the gripping portion. At this time, if the locking means is operated so as to release the gripping part with respect to the main body, the gripping part becomes movable along the linear guide, so that the position of the work is slightly displaced from the gripping device main body. However, the work can be accurately gripped by moving only the gripping part.

When the locking means is actuated from the state of gripping the work to fix the gripping part to the main body of the gripping device, the positional relationship between the gripped work and the main body of the gripping device can be determined. If the gripping device main body is moved to the set position taught in advance and the work is released, the work is set at the predetermined position with high accuracy. Further, when the gripping device main body is moved to a preset setting position without operating the locking means while gripping the work, a slight positional deviation can be absorbed even in the setting work. Further, a rotating means for rotating the grip portion relative to the main body of the grip device is provided, and when the rotating position of the grip portion is changed between a state of gripping the work and a state of releasing the work, the grip position is changed with respect to the work. It is possible to add two degrees of freedom.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram showing a work gripping device according to an embodiment of the present invention, FIG. 2A is a front view showing the work gripping device according to the same embodiment, and FIG. 2B is a side view of the same. is there.

First, an outline of the construction of a work gripping device according to the present invention will be described with reference to FIG. Figure 1 (A)
As shown in FIG. 2, the work gripping device according to the present embodiment includes a gripping device main body 3, a gripping portion 2, a linear guide 4, and a locking means 5. It is attached and moves according to a trajectory taught in advance. Further, the grip portion 2 can be moved in one direction (horizontal direction in the case of FIG. 1) with almost no load by the linear guide 4 with respect to the grip device main body 3. The lock means 5 is a means for fixing and releasing the grip portion 2 which is movable in the left-right direction by the linear guide 4, and when the lock means 5 is operated to fix the grip portion 2, the lock means 5 is gripped. The part 2 is always fixed to a fixed position with respect to the gripping device body 3. For example, in the embodiment shown in FIG.
Is set so as to be fixed to the center of the gripping device main body 3 when the locking means 5 is operated (see FIG. 1C).

The gripping device body 3, the gripping portion 2, the linear guide 4, and the locking means 5 described above are the main elements constituting the gripping device for the work of the present invention. An example will be explained. As shown in FIGS. 2A and 2B, the gripping device main body 3 attached to the robot arm 6 includes a base side main body 3a directly attached to the robot arm 6 and a driven side main body 3b to which the linear guide 4 is attached. The linear bushes 7 are configured to be movable toward and away from each other. A compression coil spring 8 is mounted between the two gripping device bodies 3a and 3b.
However, when they come close to each other, the elastic force of the compression coil spring 8 restores the original position. By providing the linear bush 7 and the compression coil spring 8, the two upper and lower bodies 3a and 3b approach each other against the elastic force of the compression coil spring 8 when the grip portion 2 contacts the work 1 when gripping the work 1. Will be moved to. Therefore, the work 1 due to the interference between the grip portion 2 and the work 1
Alternatively, it is possible to prevent the grasping part itself from being damaged.

Further, in order to detect such a gripping error of the work 1 and call attention to the surroundings as a work abnormality, or to reset the gripping operation of the work, in this embodiment, one body 3b is provided. The fixing pin 9 is attached, the photo sensor 10 is attached to the other main body 3a, and the fixing pin 9 approaches the photo sensor 10, that is, the grip portion 2 interferes with the work 1 and the driven side main body 3b becomes the base side main body. Three
When approaching a, the photo sensor 10 outputs a signal. In the driven-side main body 3b according to this embodiment,
One of the linear guides 4 including the rail 4b and the rail receiver 4a (rail receiver 4a) is fixed, and the rail 4b
Is fixed to a grip portion 2 described later.

A chuck actuating actuator 5a, which is a locking means, is fixed to the driven-side main body 3b, and the two chucks 5b attached to the actuator 5a are opened and closed. The structure of the chuck actuating actuator 5a according to the present embodiment is not particularly limited, but for example, a fluid cylinder, an electric motor, or the like can be used. Further, the chuck 5b constituting the locking means is opened and closed so as to sandwich the grip portion 2 described later,
When the two chucks 5b are closed, the grip portion 2 is fixed to the center of the main body 3. The grip portion 2 according to the present embodiment is fixed to the rail 4b that constitutes the above-described linear guide 4, and the linear guide 4, that is, the rail 4b and the rail receiver 4a slide to cause the grip portion 2 in FIG.
It is movable with respect to the main body 3 in the left-right direction in (A) and in the direction perpendicular to the paper surface in FIG. 2 (B). Therefore, when the chuck 5b which is the locking means is opened to release the grip portion 2, when an external force acts on the grip portion 2, the grip portion 2 slides along the linear guide 4 between the chucks 5b and 5b. It will be.

The work to be gripped and conveyed by the gripping device of this embodiment is the electric motor 1 as shown in FIG. 2, and the tip of the gripping portion 2 has a concave portion corresponding to the outer shape of the electric motor 1. (Vacuum pad) 11 is formed. A through hole 12 is formed in the vacuum pad 11, and the vacuum pad 11 communicates with a vacuum pump (not shown) via a rotary elbow 13. Then, when the vacuum pump is operated, the electric motor 1 is adsorbed by the vacuum pad 11 from the rotary elbow 13 through the through hole 12. On the other hand, in order to release the electric motor 1 adsorbed on the vacuum pad 11, the suction of the vacuum pump may be stopped.

Next, the operation of the work gripping apparatus according to the present embodiment will be described with reference to FIGS.
A description will be given with reference to (A) and (B). As shown in FIG. 1A, the electric motor 1, which is a work, is carried into the line side while being accommodated in the supply pallet 14. Although the recess 15 for fixing the electric motor 1 is formed in the supply pallet 14, the installation accuracy of the electric motor 1 in the supply pallet 14 and the carry-in installation accuracy of the supply pallet itself on the line side are not guaranteed. This is rougher than the operation accuracy of the robot equipped with the gripping device of the embodiment.

Therefore, as shown in FIG. 1A, even if the gripping device is attached to the tip of the arm 6 of the robot and the gripping device is brought close to the electric motor 1 of the supply pallet 14, the concave portion of the vacuum pad is not always formed. The electric motor 1 does not always match 11. However, in the work gripping device according to the present embodiment, when the gripping device main body 3 is brought closer to the electric motor 1, the chuck 5b is opened by the chuck actuating actuator 5a so that the gripping portion 2 is free from the gripping device main body 3. Since it is in the state,
As shown in (B), the vacuum pad 11 of the grip portion 2
When the electric motor 1 comes into contact with the electric motor 1, the grip portion 2 moves along the linear guide 4 so that the electric motor 1 fits into the concave portion 11 of the vacuum pad. As a result, the electric motor 1 is fitted into the concave portion 11 of the vacuum pad and sucked by the vacuum pump.

When the electric motor 1 is attracted to the vacuum pad 11 in this manner, the gripping device main body 3 is raised until the electric motor 1 comes out of the supply pallet 14 while keeping the gripping portion 2 free. This is because if the grip portion 2 is fixed before the electric motor 1 is taken out from the supply pallet 14, the fixing force of the recess 15 formed in the supply pallet is larger than the suction force of the vacuum pad 11, the electric motor 1 Is likely to come off from the vacuum pad 11. However, in the present invention, the timing for fixing the grip portion 2 is not limited to the embodiment shown in FIGS. 1 and 2, but may be set immediately after the electric motor 1 is sucked. The timing of such an operation command to the gripping device can be output based on, for example, the coordinates of the movement trajectory of the robot taught in advance.

When the electric motor 1 is taken out from the supply pallet 14 in this manner, the chuck 5b is closed by the chuck operating actuator 5a and the grip portion 2 is fixed to the center of the grip device main body 3. As a result, the relative positional relationship between the electric motor 1 which is the work and the robot arm 6 is determined. Therefore, if the electric motor 1 is moved according to the locus that is sandwiched in advance, the electric motor 1 will be moved according to the positional accuracy of the robot. Can be transported and installed. Then, the robot arm 6 is operated to convey the electric motor 1 attracted to the grip portion 2 to a predetermined position such as an assembly line, and the vacuum pump is stopped to install the electric motor 1.

As described above, the work gripping device of this embodiment has an extremely simple structure, and by adding a degree of freedom in the direction along the linear guide 4 to the gripping part 2, it is possible to realize a low precision state. Even the supplied work 1 can be properly gripped.

The present invention is not limited to the above-mentioned embodiments, but can be modified in various ways. For example, in the above-described embodiment, the work to be gripped and conveyed is the electric motor, and the electric motor is adapted to be attracted to the vacuum pad. However, in the case where the work is plate-shaped, the structure of the gripping portion is shown in FIG. And it may be modified as shown in FIG.
FIG. 3 is a conceptual view showing a work gripping device according to another embodiment of the present invention, FIG. 4A is a front view showing the work gripping device according to the same embodiment, and FIG. 4B is a side view of the same. Is.

The plate 1 shown in FIG. 3 is a supply pallet 1
4 is loaded on the line side in a state of standing upright at a predetermined interval, and although the recess 15 for fixing the plate 1 is also formed in the supply pallet 14, the recess 1
The positioning accuracy of No. 5 is rougher than the operation accuracy of the robot as in the above-described embodiment. Therefore, in this embodiment as well, the grip means 2 is attached to the grip device main body 3 via the linear guide 4 so as to be movable in one direction, and further the locking means for fixing and releasing the floating function of the grip portion 2. 5 are provided. In particular, in this embodiment, the grip claws 16 are provided so that the structure of the grip portion 2 is performed by the grip method instead of the suction method described above.

The specific structure is as shown in FIGS. 4A and 4B. The gripping device main body 3 attached to the robot arm 6 or the like is a linear main body 3a directly attached to the robot arm 6, and a linear body. The guide 4 is composed of a driven-side main body 3b to which the guide 4 is attached, and can slide in the vertical direction of FIGS. 4A and 4B via a slide guide (not shown). A tension coil spring 17 is mounted between the two gripping device bodies 3a and 3b, and when the two bodies 3a and 3b slide on each other, the elastic force of the tension coil spring 17 causes the two bodies 3a and 3b to move.
b is designed to be restored to its original position. By the slide guide and the tension coil spring 17, when the gripping portion 2 comes into contact with the work 1 when gripping the work 1, the two main bodies 3 a, against the elastic force of the tension coil spring 17,
The sliding parts 3 slide on each other, and the gripping part 2 approaches the main body 3. Therefore, it is possible to prevent the work 1 or the gripping part itself from being damaged due to the interference between the gripping part 2 and the work 1.

Further, similarly to the above-mentioned embodiment, the work 1
A fixing plate 9a is attached to one of the main bodies 3b in order to detect a gripping mistake of the above and call attention to the surroundings as an abnormal work,
When the photosensor 10 is attached to the other main body 3a and the fixed plate 9a approaches the photosensor 10, that is, when the driven main body 3b approaches the base main body 3a due to the gripping portion 2 interfering with the work 1, the photosensor 10 I am trying to output the signal from. Driven body 3 according to the present embodiment
One of the linear guides 4 (rail 4a) including a rail 4b and a rail receiver 4a is fixed to b, and the rail receiver 4b is fixed to a grip portion 2 described later.

A chuck actuating actuator 5a, which is a locking means, is fixed to the base side main body 3b, and two chucks 5b attached to the actuator 5a are opened and closed. The structure of the chuck actuating actuator 5a according to the present embodiment is not particularly limited, but for example, a fluid cylinder, an electric motor, or the like can be used. Further, the chuck 5b constituting the locking means is opened and closed so as to hold the grip portion 2 described later,
When the two chucks 5b are closed, the grip portion 2 is fixed to the center of the main body 3.

The gripping portion 2 according to the present embodiment is fixed to the rail receiver 4b which constitutes the above-mentioned linear guide 4, and the linear guide 4, that is, the rail 4a and the rail receiver 4b slide along with each other as shown in FIG. In FIG. 4B, the main body 3 is moved in the left-right direction in FIG.
It is movable with respect to. Therefore, when an external force acts on the grip portion 2 when the chuck 5b, which is the locking means, is opened and the grip portion 2 is released, the chucks 5b, 5b.
In the meantime, the grip portion 2 slides along the linear guide 4.

The work gripped and conveyed by the gripping device of this embodiment is a plate (eg, chassis of a CD device) 1 as shown in FIG. 3, so that the tip of the gripping portion 2 can easily grip the plate 1. Is provided with a gripping claw 16 and the two gripping claws 16 are driven by the gripping claw actuating actuator 17.
Is designed to open and close. This gripper claw actuating actuator 17 can also be constituted by a fluid cylinder, an electric motor, or the like. Further, it is preferable to form a taper 18 at the tip of the grip claw 16 in order to facilitate the attraction of the plate 1. In addition, “19” in FIG. 4 is a fall prevention plate for preventing the plate 1 from falling when the plate 1 is gripped.

Next, the operation of the work gripping device according to this embodiment will be described with reference to FIGS. 3 (A) (B) (C) (D) and FIGS. 4 (A) (B). As shown in FIG. 3A, the plate 1, which is the work, is carried into the line side while being accommodated in the supply pallet 14. The installation accuracy of the plate 1 on the supply pallet 14 and the carry-in installation accuracy of the supply pallet itself are rougher than the operation accuracy of the robot equipped with the gripping device of this embodiment. In particular, when the plate 1 is housed in the supply pallet 14 in a leaning state as in this embodiment, there is an inclination error θ of the plate 1 in addition to the offset error d between the plate 1 and the gripping device. .. Therefore, FIG.
As shown in, even if the gripping device is attached to the tip of the arm 6 of the robot and the gripping device is brought close to the plate 1 of the supply pallet 14, the plate 1 is not always located between the gripping claws 16.

However, in the work gripping device according to the present embodiment, when the gripping device main body 3 is brought closer to the plate 1, the chuck 5b is opened by the chuck actuating actuator 5a, and the gripping portion 2 is moved relative to the gripping device main body 3. Since it is in a free state, as shown in FIG. 3 (B), when the grip claw 16 of the grip part 2 contacts the plate 1, the plate 1 is moved between the grip claws 16 by the taper 18 formed at the tip of the grip claw. It is called in, and the grip portion 2 moves along the linear guide 4 so that the plate 1 is inserted between the grip claws. Then, the actuator 1 for operating the grip claw
By operating 7, the grip claw 16 is closed and the plate 1 is gripped.

When the plate 1 is gripped by the gripping claws 16 in this way, the gripping device main body 3 is raised until the plate 1 is taken out from the supply pallet 14 while the gripping portion 2 remains free. This is because when the grip portion 2 is fixed to the main body 3 before the plate 1 is taken out from the supply pallet 14, the fixing force of the recess 15 formed in the supply pallet 14 is larger than the grip force of the grip claw 16. This is because the plate 1 may drop from the grip claw 16. However, in the present invention, the timing of fixing the grip portion 2 is not limited to the embodiment shown in FIG.
It is also possible to set it immediately after gripping the plate 1.

When the plate 1 is taken out from the supply pallet 14 in this manner, the chuck operating actuator 5
The chuck 5b is closed by a and the grip portion 2 is fixed to the center of the grip device main body 3. As a result, the relative positional relationship between the plate 1 which is the work and the robot arm 6 is determined. Therefore, if the plate 1 is moved in accordance with the trajectory previously held, the plate 1 will be moved according to the positional accuracy of the robot.
Can be installed in place. Finally, the plate 1 gripped by the grip claws 16 by operating the robot arm 6
Is conveyed to a predetermined position such as an assembly line, and the grip claw 1
Open 6 and install plate 1.

As described above, the work gripping device of the present embodiment also has an extremely simple structure, and by adding a degree of freedom in the direction of the linear guide 4 to the gripping part 2, the work supplied in a low precision state. However, it can be properly gripped.

The work gripping device of the present invention can be further modified. 5A and 5B are views showing a work gripping device according to another embodiment of the present invention. FIG. 5A is a front view, FIG. 5B is a side view of the same, and FIG. 6 is an embodiment shown in FIG. 6A is a front view for explaining the action of FIG. 6A, FIG. 6A shows before the operation of the rotating means, and FIG. 6B shows after the operation of the rotating means.
In the above-described embodiment, the locking means for fixing and releasing the grip portion is constituted by the chuck, but the locking means of the present invention can be realized by other configurations. Further, both are specific examples in which the gripping portion is free in only one direction with respect to the gripping device main body, but by adding a rotating means for rotating the gripping portion relative to the gripping device main body, It is also possible to give the gripping portion two or more degrees of freedom with respect to the gripping device main body.

That is, as shown in FIGS. 5A and 5B, the gripping device main body 3 attached to the robot arm 6 and the like has the base main body 3a directly attached to the robot arm 6 and the linear guide 4 attached thereto. The driven-side main body 3b is configured to be slidable with respect to each other in the vertical direction of FIGS. 5A and 5B via the slide guide 20. In addition, these two gripping device bodies 3a and 3b
A tension coil spring 17 is mounted between the two bodies, and when the two main bodies 3a and 3b slide on each other, the elastic forces of the tension coil springs 17 restore the two main bodies 3a and 3b to their original positions. This slide guide 20
When the grip portion 2 comes into contact with the work 1 when the work 1 is gripped by the tension coil spring 17, the two main bodies 3a and 3 slide against each other against the elastic force of the tension coil spring 17, so that the grip portion 2 becomes the main body. It will approach 3.
Therefore, it is possible to prevent the work 1 or the gripping part itself from being damaged due to the interference between the gripping part 2 and the work 1.

Further, as in the above-mentioned embodiment, the work 1
In order to detect a gripping mistake of the above and call attention to the surroundings as an abnormal work, a fixing pin 9 is attached to one main body 3b,
When the photo sensor 10 is attached to the other main body 3a and the fixing pin 9 approaches the photo sensor 10, that is, when the driven side main body 3b approaches the base main body 3a due to the grip portion 2 interfering with the work 1, the photo sensor 10 I am trying to output the signal from. Driven body 3 according to the present embodiment
One of the linear guides 4 including a rail 4b and a rail receiver 4a (rail receiver 4a) is fixed to b, and the rail 4b is fixed to a grip portion 2 described later.

A protrusion actuating actuator 5a, which is a locking means, is fixed to the driven-side main body 3b.
The protrusion 5b attached to the actuator 5a is moved back and forth. On the other hand, the grip portion 2 is formed with a protrusion engaging portion 21 that engages with the protrusion 5b. The structure of the projection actuating actuator 5a according to the present embodiment is not particularly limited, but, for example, a fluid cylinder or the like can be used. In addition, the protrusion 5 that constitutes the locking means
b moves forward and backward toward the projection engagement portion 21, and when the projection 5b advances and engages with the projection engagement portion 21, the grip portion 2 is fixed to the center of the main body 3.

The grip portion 2 according to this embodiment is fixed to the rail 4b constituting the above-mentioned linear guide 4, and the linear guide 4, that is, the rail 4b and the rail receiver 4 is fixed.
By sliding with a, it is movable with respect to the main body 3 in the left-right direction in FIG. 5A and in the direction perpendicular to the paper surface in FIG. 5B. Therefore, when the projection 5a, which is the locking means, retracts and the engagement with the projection engagement portion 21 is released, the grip portion 2 becomes slidable along the linear guide 4. Since the work gripped by the gripping device of the present embodiment is the plate (for example, the chassis of the CD device) 1 as shown in FIG. 5, the gripping claw 16 is provided at the tip of the gripping portion 2 so that the plate 1 can be easily gripped. Is provided, and the two gripping claws 16 are opened and closed by the gripping claw actuating actuator 17. This gripper actuating actuator 1
7 can also be composed of a fluid cylinder, an electric motor, or the like. In addition, it is preferable to form a taper 18 at the tip of the grip claw 16 in order to facilitate the attraction of the plate 1 (see FIG. 5A). Note that FIG. 5 (B)
Inside, “19” is a fall prevention plate for preventing the plate 1 from falling when the plate 1 is gripped.

The workpiece gripping device of this embodiment is provided with a rotary actuator (rotating means) 23 for rotating the gripping part 2 relative to the gripping device body 3. The rotary actuator 23 is preferably provided, for example, when the posture of the work when taken out from the supply pallet is different from the posture of the work when the work is transported and installed. For example, as shown in FIG. 6A, when the plate 1 that is a work is gripped, the plate 1 is accommodated in the supply pallet 14 in an upright posture.
When it is desired to change the plate 1 horizontally when installing it at a predetermined position, the rotary actuator 23 may be rotated by about 90 °.

Next, the operation of the work holding device according to the present embodiment will be described with reference to FIGS. 5 (A), 5 (B) and 6 (A).
This will be described with reference to (B). As shown in FIG. 3 (A), the plate 1 as the work is carried into the line side while being accommodated in the supply pallet 14 as shown in FIG. 3 (A). The plate installation accuracy of the supply pallet 14 and the carry-in installation accuracy of the supply pallet itself are rougher than the operation accuracy of the robot equipped with the gripping device of this embodiment. In particular, when the plate 1 is housed in the supply pallet 14 in a leaning state as in the present embodiment, an offset error d between the plate 1 and the gripping device
Besides, there is also a plate tilt error θ. Therefore, even if the gripping device is attached to the tip of the arm 6 of the robot and the gripping device is brought close to the plate 1 of the supply pallet 14, the plate 1 is not always positioned between the gripping claws 16.

However, in the work gripping device according to the present embodiment, when the gripping device main body 3 is brought closer to the plate 1, the projection 5b is retracted by the projection actuating actuator 5a to engage with the projection engaging portion 21. Release the grip 2
Since the gripping device main body 3 is in a free state, when the gripping claws 16 of the gripping portion 2 come into contact with the plate 1,
The plate 1 is formed by the taper 18 formed at the tip of the grip claw.
Is drawn between the gripping claws 16, and further, the gripping claws 16
The gripper 2 moves along the linear guide 4 so that the plate 1 is inserted therebetween. Then, by operating the gripping claw operating actuator 17, the gripping claw 16 is closed and the plate 1 is gripped.

When the plate 1 is gripped by the grip claws 16 in this way, the gripping device main body 3 is raised until the plate 1 comes out of the supply pallet 14 while the gripping portion 2 remains free. This is because if the grip portion 2 is fixed before the plate 1 is taken out from the supply pallet 14, and if the fixing force of the recess 15 formed in the supply pallet 14 is larger than the grip force of the grip claw 16, the plate 1 This is because there is a risk that the will fall from the grip claws 16. However, in the present invention, the timing of fixing the gripping portion is not limited to the embodiment shown in FIG. 6, but can be set after gripping the plate.

When the plate 1 is taken out from the supply pallet 14 in this way, the protrusion 5b is moved forward by the protrusion actuating actuator 5a to engage with the protrusion engaging portion 21, so that the gripping portion 2 is positioned at the center of the gripping device main body 3. Fix it. As a result, the relative positional relationship between the plate 1 which is the work and the robot arm 6 is determined. Therefore, if the plate 1 is moved in accordance with the locus previously held, the plate 1 is moved to a predetermined position according to the positional accuracy of the robot. Can be installed in

Then, the robot arm 6 is operated to convey the plate 1 gripped by the gripping claws 16 to a predetermined position such as an assembly line, and the positioning holes 24 formed in the plate 1 are inserted into the positioning pins 25 to plate the plate. 1 is set in place. At this time, the protrusion operating actuator 5a is operated again to retract the protrusion 5b, release the engagement with the protrusion engaging portion 21, and bring the grip portion 2 into a free state with respect to the grip device main body 3. Then, when the plate 1 is brought close to the positioning pin 25, even if the positioning hole 24 is slightly displaced from the positioning pin 25, the gripping portion 2 is guided along the linear guide 4 so that the positioning pin 25 engages with the positioning hole 24. The plate 1 is set at a predetermined position, and then the grip claws 16 are opened to release the plate 1.

As described above, the work gripping device of the present embodiment also has an extremely simple structure, and by adding the rotary actuator, it is possible to give the work two degrees of freedom, and in a state of low accuracy. Even the supplied work can be properly grasped and further installed at a desired position. Although the rotary actuator 23 is used to rotate the grip portion 2 by 90 ° in the above-described embodiment, such a rotation angle is not particularly limited in the present invention, and the assembly work to be applied is not limited thereto. It may be changed variously according to the situation.

[0045]

As described above, according to the present invention, a gripping part for gripping and releasing a work, and a gripping part provided between the gripping part and the main body are slidably supported with respect to the main body. Since it has a linear guide and locking means for fixing and releasing the gripping part with respect to the main body, by adding a degree of freedom to the gripping part with a simple structure, even a workpiece supplied in a low precision state can be obtained. It can be held properly. Therefore, work chuck errors are reduced, and the operating rate of the assembly line is improved. Further, since it is not necessary to use a dedicated supply pallet, it is possible to reduce extra work man-hours and costs. Further, when a rotating means for rotating the grip portion relative to the main body of the grip device is provided, and the rotation position of the grip portion is changed between a state of gripping the work and a state of releasing the work, the rotation position of the grip portion with respect to the work is changed. It is possible to add two degrees of freedom. This makes it possible to add a floating function not only when gripping a work but also when setting a work.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a work holding device according to an embodiment of the present invention.

FIG. 2A is a front view showing a work holding device according to the embodiment, and FIG. 2B is a side view of the same.

FIG. 3 is a conceptual diagram showing a work holding device according to another embodiment of the present invention.

FIG. 4A is a front view showing a work holding device according to the embodiment, and FIG. 4B is a side view of the same.

5A and 5B are views showing a work holding device according to another embodiment of the present invention, in which FIG. 5A is a front view and FIG. 5B is a side view.

6A and 6B are front views for explaining the operation of the embodiment shown in FIG. 5, in which FIG. 6A shows a state before the operation of the rotating means and FIG. 6B shows a state after the operation of the rotating means.

[Explanation of symbols]

 1 ... Work 2 ... Gripping part 3 ... Gripping device main body 4 ... Linear guide 5 ... Locking means

Claims (2)

[Claims] 1. A gripping part for gripping and releasing a work, a linear guide provided between the gripping part and the main body for slidably supporting the gripping part with respect to the main body, and the gripping part for the main body. And a locking means for fixing and releasing the workpiece with respect to the workpiece gripping apparatus. 2. The gripping device for the work according to claim 1, further comprising a rotating means for rotating the gripping portion relative to the main body.