JPH0718439Y2 - Work gripping device - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention (1) Industrial Application Field of the Invention The present invention is provided with first and second gripping members made of a conductive metal so that their tip portions can approach and separate from each other. ,
At the tip of the first grip member, a grip projection for gripping a work made of a conductive metal with the grip surface provided at the tip of the second grip member is provided so as to project toward the second grip member. Work gripping device.

(2) Conventional Technology Conventionally, such a device is already known from, for example, Japanese Utility Model Laid-Open No. 55-88335.

(3) Problems to be Solved by the Invention By the way, the work gripping device is used, for example, to move a work formed by a press machine to the next step, and to fix the work between the grip projection and the grip surface. Although the work is gripped, the work may not be gripped between the grip projection and the grip surface when the size of the work after molding becomes equal to or less than the specified size due to a press error of the pressing machine. Thus, in the past, in order to deal with such a case, a limit switch or a photoelectric switch for detecting the work is arranged at the movement position of the work to the next process, and, for example, after the work gripping device starts moving, When a work is not detected by the limit switch or photoelectric switch after a few seconds, it is determined that the work gripping device is not gripping the work, and an abnormality alarm is issued.

However, as described above, when the shape of the work changes, the positions of the limit switch and the photoelectric switch must be changed, and it takes time until the signal indicating that the work is unsuccessfully gripped is output. Therefore, it is difficult to cope with, for example, speeding up of the press machine.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a work gripping device capable of immediately detecting a gripping failure of the work regardless of the shape change of the work.

B. Configuration of the Invention (1) Means for Solving the Problems To achieve the above object, according to the present invention, the gripping protrusion and the first gripping member are electrically insulated, and the first and second gripping members are electrically insulated. A stopper capable of abutting against the other gripping member is provided on one side so as to prevent the gripping projection from abutting on the second gripping member in the abutting state. A detector that detects an electrical conduction state between the grip projection and the second grip member is connected.

(2) Operation According to the above configuration, when the work is gripped between the grip projection and the grip surface, the grip projection and the grip surface are electrically connected to each other through the work, and the grip of the work fails and the stopper stops. Therefore, when the distance between the tip portions of both gripping members is minimized, the gripping protrusion is not in contact with the second gripping member, and therefore the gripping protrusion and the second gripping member are electrically non-conductive. Then, it becomes possible to immediately detect whether or not the work is gripped.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 to 5 show an embodiment of the present invention. FIG. 1 is a partially cutaway side view, FIG. 2 is a bottom view taken along the arrow II in FIG. 1, and FIG. 1 is a front view seen from the arrow III in FIG. 1, FIG. 4 is a vertical sectional front view of the tips of the first and second gripping members in the state where the work is gripped, and FIG. 5 is shown in FIG. 4 when the gripping of the work fails. It is a corresponding vertical front view.

First, in FIG. 1 to FIG. 3, a robot movable between a pressing machine (not shown) for processing a conductive metal such as a steel plate and a predetermined position prepared for the next step after the pressing step is shown. A work gripping device 2 according to the present invention is arranged on the arm 1, and the work W after gripping is pressed by the work gripping device 2.

The work gripping device 2 is guided by a pair of guide rods 4, 4 each having one end fixed to a bracket 3 provided at the end of the arm 1 and extending parallel to each other, and the guide rods 4, 4. Cylindrical moving bodies 5 and 5, a pair of support plates 6 and 6 respectively hung from the lower ends of the moving bodies 5 and 5, and fixedly supported by the bracket 3 and connected to the support plates 6 and 6. Cylinder 7, first gripping member 8 fixed to both support plates 6, 6, second gripping member 9 swingably supported by both support plates 6, 6, and tip of first gripping member 8 And a pair of springs for urging the second gripping member 9 so that the tip of the second gripping member 9 is close to the tip of the first gripping member 8. 12,12 and their springs 12,12
The guide rod 4, which can be brought into contact with the second gripping member 9 in order to swing the second gripping member 9 against the spring force of the guide rod 4,
And a cam 13 provided at the other end of 4.

The other ends of both guide rods 4, 4 are connected to each other via a connecting member 14, and the cam 13 is fixedly provided on the connecting member 14. Bushings 15 are provided between the movable bodies 5 and 5 and the guide rods 4 and 4, respectively. The cylinder 7 extends below the both guide rods 4, 4 in a direction opposite to the extending direction of the guide rods 4, 4 and has an axis line parallel to the axis lines of the both guide rods 4, 4 to provide the bracket 3 Connected to. Moreover, the piston rod 7a of the cylinder 7 pierces the bracket 3 in a freely movable manner, and the tip of the piston rod 7a is connected to both the support plates 6, 6 via the connecting pin 16. Therefore, the support plates 6 and 6, that is, the movable bodies 5 and 5, reciprocate along the guide rods 4 and 4 in accordance with the expansion and contraction operation of the cylinder 7.

The first gripping member 8 is formed of a conductive metal on a flat plate. The first gripping member 8 is arranged so as to be substantially parallel to the axes of the two guide rods 4, 4, and the rear end of the first gripping member 8 has both support plates 6, 4. It is fixed to the tip of 6. On the other hand, the second gripping member 9 is the work W.
At the center of the rear end of the gripping portion 9a having a gripping surface 17 capable of abutting the lower surface of the gripping portion 9a on the upper surface of the tip end portion.
Are connected to each other and are basically formed in a substantially L-shape with a conductive metal. The cylindrical spacers 19 and 19 are provided on both support plates 6 and 6.
An intermediate portion of a support portion 9b interposed between and is supported by both support plates 6, 6 via a support shaft 18. That is, the first and second gripping members 8 and 9 are connected so that their tip portions can approach and separate from each other.

The springs 12 and 12 are torsion springs surrounding the spacers 19 and 19, and one end of each spring 12 and 12 is provided in the second gripping member 9 at a continuous portion of the gripping portion 9a and the supporting portion 9b. Locked on the upper surfaces of the pair of locking parts 20, 20, respectively,
The other end of 12 is locked to the lower surface of the rear end of the first grip member 8. As a result, the second gripping member 9 is rotationally biased in the direction in which the gripping surface 17 at the tip of the gripping portion 9a moves away from the tip of the first gripping member 8.

By the way, above the support portion 9b of the second gripping member 9, the gripping surface 17 at the tip of the gripping portion 9a is attached to the upper surface of the rear end of the first gripping member 8 with the gripping surface 17 being substantially parallel to the first gripping member 8. The engaging claws 21 are provided so that the engaging claws 21 engage the upper surface of the rear end of the first gripping member 8 so that the gripping surface 17 moves away from the tip of the first gripping member 8. Of the spring
The rotational position of the second gripping member 9 is regulated by the rotational urging force of 12 and 12. In addition, at the upper end of the support portion 9b, the moving body 5,5
And when the support plates 6, 6 move forward, both guide rods
An abutting portion 22 is provided which abuts on the cam 13 provided at the tips of the 4, 4 and rotates the second gripping member 9 against the spring force of the springs 12, 12. Therefore, when the cylinder 7 extends and the two moving bodies 5 and 5 and the support plates 6 and 6 move forward, the cam 13 comes into contact with the abutting portion 22 so that the second
The gripping member 9 is rotated in a direction in which the gripping surface 17 is brought closer to the tip portion of the first gripping member 8.

Referring also to FIGS. 4 and 5, the gripping projection 10 and the stopper 11 are, for example, screw members having conical tips 10a and 11a. Thus, at the tip of the first gripping member 8, an insulating member 23, which is basically made of an insulating material in a cylindrical shape and has flanges at both ends, is provided with the flanges at both ends of the first gripping member 8. The gripping projections 10 are fixed to the upper and lower surfaces so that they are engaged with each other.
The spacer 24 is interposed between the tip end portion 10a and the insulating member 23 while being positioned at the lower position, and is inserted into the insulating member 23. Thus, the ring-shaped washer 25 and the ring-shaped terminal member 26 are provided on the gripping protrusion 10 at the portion projecting upward from the first gripping member 8.
Is inserted and the washer 25 and the terminal member 26 are insulated.
A nut 27 is screwed to the grip projection 10 so as to be sandwiched between the nut 27 and the grip projection 10. On the other hand, the stopper 11 is screwed into the first gripping member 8 with its tip 11a being in the lower position, and the nut 28 is attached to the stopper 10 at the portion projecting upward from the first gripping member 8.
Are screwed together. Thus, the amount of protrusion of the tip 11a of the stopper 11 from the first grip member 8 is determined by the tip 10a of the grip projection 10.
The amount of protrusion from the first gripping member 8 is set to be the same.

On the other hand, the gripping surface 17 of the second gripping member 9 is provided with a tapered first concave portion 29 into which the tip end portion 11a of the stopper 11 is fitted, and is tapered corresponding to the tip end portion 20a of the gripping protrusion 10. A second recess 30 formed in a shape is provided corresponding to the grip projection 10. Moreover, the second recess 30 is formed by the tip 11a of the stopper 11.
5 is in contact with the bottom surface of the first recess 29 as shown in FIG. 5, the tip 10a of the gripping projection 10 has a depth that makes it impossible to contact the bottom surface of the second recess 30. It is formed.

Thus, the stopper 11 has a function of gripping the work W between itself and the gripping surface 17 as shown in FIG. 4, and the work W between the first and second gripping members 8 and 9 as shown in FIG. And the function of keeping the minimum distance between the tip portions of the first and second gripping members 8 and 9 in the state where they do not exist.

By the way, a detector 31 is connected to the second gripping member 9 and the terminal member 26 electrically connected to the gripping protrusion 10 fixed to the first gripping member 8. Thus, the detector 31 has a first
The gripping member 8 is for detecting an electrical conduction state between the gripping protrusion 10 in an electrically insulated state and the second gripping member 9.

Next, the operation of this embodiment will be described. For example, when gripping a work W formed by a press,
First, the cylinder 7 is contracted to move the moving body 5, 5
And the support plates 6 and 6 are set to the positions shown in FIGS. 1 and 2, and the second gripping member 9 is rotated to a position where its gripping surface 17 is maximally separated from the tip of the first gripping member 8. deep.

Then, when the cylinder 7 is extended, the movable bodies 5 and 5 and the support plates 6 and 6 move forward along the guide rods 4 and 4, and when the contact portion 22 contacts the cam 13, the second gripping member 9 moves. The gripping surface 17 is rotated against the spring force of the springs 12 and 12 in a direction to bring the gripping surface 17 closer to the tip of the first gripping member 8. When the work W exists between the first and second grip members 8 and 9, the work W is gripped between the grip projection 10 and the stopper 11 and the grip surface 17, as shown in FIG. In this state, the gripping protrusion
10. The workpiece W and the second gripping member 9 are electrically connected.

However, when the work W cannot be gripped for some reason, the second gripping member 9 rotates until the tip 11a of the stopper 11 fits into the first recess 29, as shown in FIG. In this state, the gripping protrusion 10 is not in contact with the second gripping member 9, so that the detector 31 can detect that the work W is not gripped.

In this way, it is possible to immediately detect whether or not the work W is gripped, and it is possible to cope with speeding up of the press molding line. If the workpiece W is grasped between the grasping projection 10 and the grasping surface 17, regardless of the shape change of the work W,
It is possible to reliably detect whether or not the work W is gripped.

In the above embodiment, the workpiece W is attached to the stopper 11 and the gripping surface.
Although it can be grasped between 17 as well, as shown in FIG. 6, the stopper 11 ′ may be any one that defines the minimum distance between the tip portions of the first and second grasping members 8 and 9. That is, the stopper 11 'does not contact the second gripping member 9 while gripping the work W between the gripping protrusion 10 and the gripping surface 17, but does not contact the second gripping member 9 when the work W is not gripped. It is provided on the first gripping member 8 with a length such that the gripping projection 10 abuts against the second gripping member 9 in the abutting state.

In this way, the stopper 11 ′ does not grip the work W with the gripping surface 17, but when the gripping of the work W fails, the gap between the gripping projection 10 and the second gripping member 9 is electrically non-contact. The conductive state can be achieved, and the same effect as that of the above-described embodiment can be obtained.

C. Effect of the Invention As described above, according to the present invention, when a work is gripped between the grip projection and the grip surface, the grip projection and the grip surface are electrically connected via the work, and the grip of the work is performed. If the gap between the tip portions of both gripping members is minimized by the stopper due to the failure of the gripping projection, the gripping projection is not brought into contact with the second gripping member, so that the gripping projection and the second gripping member are electrically disconnected. By so doing, it is possible to reliably and immediately detect whether or not the work is gripped, and if the work can be gripped between the grip projection and the grip surface, adjustment work for changing the shape of the work is unnecessary.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention. FIG. 1 is a partially cutaway side view, FIG. 2 is a bottom view taken along the arrow II in FIG. 1, and FIG. 1 is a front view seen from the arrow III in FIG. 1, FIG. 4 is a vertical sectional front view of the tips of the first and second gripping members in the state where the work is gripped, and FIG. 5 is shown in FIG. 4 when the gripping of the work fails. A corresponding vertical sectional front view and FIG. 6 show another embodiment of the present invention and are side views of essential parts in a work gripping state. 2 ... Work gripping device, 8 ... First gripping member, 9 ... Second gripping member, 10 ... Gripping protrusion, 11, 11 '... Stopper, 1
7 ... Gripping surface, 29 ... First recess, 30 ... Second recess, 31 ...
… Detector, W… Work

Claims (2)

[Scope of utility model registration request] 1. A first and a second gripping member (8, 9) made of a conductive metal are provided so that their tip portions can approach and separate from each other, and the tip end portion of the first gripping member (8) is The second gripping member (9) has a gripping projection (10) for gripping the work (W) made of a conductive metal with the gripping surface (17) provided at the tip of the second gripping member (9). In the work gripping device provided so as to project to the side, the gripping protrusion (10) is electrically insulated from the first gripping member (8), and one of the first and second gripping members (8, 9) (8) is Is the other gripping member (9)
Stoppers (11, 11 ') capable of abutting against the gripping projections (10) are provided so as to prevent the gripping projections (10) from abutting against the second gripping member (9). The second gripping member (9) has a gripping protrusion (10) and a second gripping member (9).
A work gripping device, to which a detector (31) for detecting an electrical continuity between the workpieces is connected. 2. The first gripping member (8) has the same amount of protrusion toward the second gripping member (9) as the gripping protrusion (10) and the work (W) between the gripping surface (17). A stopper (11) capable of gripping the projection is provided adjacent to the grip projection (10), and the grip surface (17) of the second grip member (9) has a first recess (29) corresponding to the stopper (11). ) And the second corresponding to the grip projection (10)
A recess (30) is provided, and the second recess (30) has a second recess (30) at the tip of the gripping protrusion (10) in a state where the stopper (11) is in contact with the bottom surface of the first recess (29). The work gripping device according to claim 1, wherein the work gripping device is formed with a depth that makes it impossible to contact the bottom surface of the work.