JPS638964Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an external contact detection device that also serves as a safety device to prevent damage when a moving part such as the tip of a robot's wrist comes into contact with another fixed part.

When an industrial robot 1 as shown in Fig. 1 performs work such as welding, the welding torch 2 attached to the tip of the robot's wrist may be attached to the workpiece or jig due to workpiece accuracy, workpiece positioning accuracy, or operator error. Depending on the degree of contact, the welding torch 2 may be deformed or damaged, and in severe cases, the robot's wrist mechanism may be damaged.

Conventionally, as shown in FIG. 2, a support member 3 and a workpiece side member 4 such as a torch holder are used as a protective device to stop the machine or protect the robot's wrist in the event of such a contact accident. A Bakelite ring 5, which easily breaks due to impact, is inserted between the robot and the robot, and is attached from both sides with screws 6 to prevent damage from spreading to the robot body due to the Bakelite ring 5 breaking in the event of a contact accident. ing.

However, this method
Even if the Bakelite ring breaks, the robot itself does not have the ability to detect it, so until the operator notices it, the robot will continue to operate without any functionality, and once it breaks, it will not be reproducible, so the Bakelite ring will need to be replaced. Yes, the robot must be taught again when it is repaired and restarted.
There are many practical problems.

Therefore, the present proposal aims to provide a sensor that can provide a contact detection function when a workpiece side member supported by such a robot or a device having an operating part contacts another fixed part such as a workpiece. be.

Hereinafter, the present invention will be explained in detail with reference to an embodiment shown in the drawings.

In FIGS. 3 to 5, 7 is the support member 3.
The frame body of the detection device is fixed to the tip of the frame body, and consists of an outer frame 8 and a side plate 9. Reference numeral 10 denotes a mounting piece of the workpiece side member 4 to which the welding torch 2 is attached, and faces the side plate 9. 11 is a spherical bearing supported by the side plate 7; 12 is a slide shaft having one end fixed to the mounting piece 10 and the other end having a spherical surface, and is supported by the spherical bearing 11 so as to be able to slide in the axial direction. . Reference numeral 13 denotes an elastic body inserted between the spherical bearing 11 and a nut 14 that is fitted into the slide shaft 12 and is screwed and fixed to the tip of the slide shaft 12 (in the figure, disc springs are arranged in opposite directions to each other). The mounting piece 10 of the workpiece side member 4 is pressed toward the side plate 9 of the frame body 7. Reference numeral 15 denotes a limit switch mounted within the outer frame 8; 16 a dog rotatably mounted on the outer frame 8 for opening and closing the limit switch 15;
The ends of the two spherical surfaces are in contact. 17a, 17b,
17c is a roller provided on the mounting piece 10 and comes into contact with the surface of the side plate 9. Reference numeral 18 is an engagement piece provided on the side plate 9 and has an inclined surface that makes contact with the roller 17a.

In such a configuration, the workpiece side member 4 normally moves 17a, 17b, 1 by the spring force of the elastic body 13.
7c is pressed against the side plate 9 and held in a steady position by engagement between the roller 17a and the engagement piece 18, but as shown in FIG. When the tip (not shown) of 4, for example, the tip of the welding torch 2 comes into contact with an external fixed part and an external force in the direction of arrow _M1 is applied to the workpiece side member 4, the workpiece side member 4 is moved by the lower two rollers 17b, 17c. It is tilted using the contact area _A1 between the side plate 9 and the side plate 9 as a fulcrum. For this reason, the slide shaft 12
is tilted via the spherical bearing 11 and retreats in the direction of arrow B against the elastic body 13, the dog 16 rotates to open (or close) the limit switch 15, and the robot immediately stops or vice versa. Return to the direction and eliminate contact with the fixed part.

Next, when an external force in the direction of arrow _M2 is applied to the workpiece side member ₄ as shown in FIG. , the slide shaft 12 slides in the direction of arrow B against the tilted elastic body 13 in the opposite direction to that in FIG. 4, and the limit switch 15 is operated.

Furthermore, when an external force is applied to the workpiece side member 4 in the direction of rotation shown by arrow M ₃ in FIG. It rides on the inclined surface of the engagement piece 18, and the workpiece side member 4 tilts in the same way as when the external force _M1 is applied.
As in the case of external force _M1 , the slide shaft 12 is moved backward and the limit switch 15 is operated.

When an external force is applied to the workpiece side member 4, for example, the tip of the torch 2 comes into contact with a fixed part of the workpiece, etc., so as shown in FIG. If it is set so that it is perpendicular to the shaft 12 and off the plane 20 that passes through the center of rotation of the spherical bearing,
When a vertical force _M4 is applied to the contact end 19, the component force becomes equal to any of the above-mentioned cases, and the workpiece side member can be tilted and the limit switch 15 can be operated.

Note that the engaging piece 18 of the present invention may be provided on each roller, and in this case, the slide shaft will move in the axial direction in response to the external force _M3 . Further, the engagement piece may not be a sloped surface but may be a low stepped portion on which the roller rides, or a recessed hole may be provided in the side plate 9 for engagement.

Further, a coil spring, rubber, etc. may be used for the elastic body 13, and the dog 16 is the limit switch 15.
It doesn't matter if it's built into.

In this way, the support member to which the workpiece side member is attached and the workpiece member are made to face each other, and the slide shaft attached to the other member is slidably supported by the spherical bearing attached to one member and connected. The workpiece side member is pressed toward the support side member by an elastic body fitted into the slide shaft, and at least one engagement piece is engaged with one of the opposing surfaces and the engagement piece is engaged with the other side of the opposing surface. At least three rollers are provided that fit together, and when the workpiece side member hits another fixed part, the opposing surface tilts against the elastic body and the slide shaft is deflected. Since the limit switch is configured to operate, for example, when an external force exceeding a certain value is applied to the workpiece side member during operation of the robot, the elastic body of the connecting part will cushion the impact and prevent the deflection of the slide shaft. This allows protective measures such as opening (or closing) the limit switch and stopping the operation of the robot to prevent damage from contact accidents.

In addition, since the fluctuation of the workpiece side member is due to the deflection within the elastic limit of the elastic body, by removing contact with the outside, it can be restored immediately and reproducibility can be ensured. There is no need for

As can be seen from the above explanation, it has a detection function for external forces in all directions, so it is suitable as an external contact sensor for the antennae of self-propelled robots and general industrial machinery with moving parts, and has a wide range of applications and contributes to industry. It is extremely large.

[Brief explanation of the drawing]

Fig. 1 is a side view of a welding robot equipped with a conventional safety device, Fig. 2 is an enlarged sectional view of the conventional safety device, and Fig. 3 is a side sectional view showing an embodiment of the present invention.
FIG. 4 is a partial plan view, FIG. 5 is a partial front view, and FIGS. 6 and 7 are side sectional views illustrating the operation. 1 is a robot body, 2 is a welding torch, 3 is a support member, 4 is a workpiece side member, 7 is a frame body, 8 is an outer frame,
9 is a side plate, 10 is a mounting piece, 11 is a spherical bearing, 12
13 is a slide shaft, 13 is an elastic body, 14 is a nut, 15 is a limit switch, 16 is a dog, 17
a, 17b, and 17c are rollers, and 18 is an engagement piece.

Claims (1)

[Scope of utility model registration request] One of the supporting side member and the workpiece side member is provided with a spherical bearing, and the other member is provided with a slide shaft that is supported so as to be able to slide in the axial direction on the spherical bearing, and the slide shaft is inserted into the slide shaft and is inserted into the workpiece side. an elastic body that presses the member and the support side member;
At least three rollers attached to one member and in contact with the opposing surface of the other member, an engagement piece on the opposing surface of the other member that contacts one of the rollers and on which the roller rides, and a slide shaft that is deflected. An external contact detection device characterized by being equipped with an operating limit switch.