JPS601994Y2 - External contact detection device - 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 the industrial robot 1 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, in the event of such a contact accident, a protective device was used to stop the machine and protect the robot's wrist.
For example, as shown in Fig. 2, a Bakelite ring 5, which easily breaks due to impact, is sandwiched between the support member 3 and a workpiece side member 4 such as a torch holder, and is attached loosely on both sides with screws 6 to prevent a contact accident. This is to prevent damage from spreading to the robot body due to breakage of the Bakelite ring 5.

However, with this method, even if the Bakelite ring 5 breaks, the robot itself does not have the ability to detect it, so the robot will continue to operate without any functionality until the operator notices it, and once it breaks, it will not be reproducible. Therefore, there are many practical problems, such as the Bakelite ring having to be replaced and the robot having to be taught again when it is repaired and restarted.

Therefore, the present invention 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 section contacts a fixed part such as a workpiece.

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

In FIG. 3, reference numeral 7 denotes a frame of the detection device fixed to the tip of the support member 3, which is composed 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 is in opposing contact with the side plate 9.

11 is a spherical bearing supported by the side plate 7; 12 is a slide shaft whose one end is fixed to the mounting piece 10 and whose other end is 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 into the slide shaft 12 and inserted between the nut 14 screwed and fixed to the tip of the slide shaft 12 and the spherical bearing 11 (in the figure, disc springs are arranged in opposite directions). The mounting piece 10 of the workpiece side member 4 is crimped onto the side plate 9 of the frame body 7.

15 is a limit switch installed in the outer frame 8;
A dog 6 is rotatably attached to the outer frame 8 and opens and closes the limit switch 15, with which the spherical end of the slide shaft 12 contacts.

17 is a recessed hole provided in the side plate 9, and 18 is a spherical taper projection provided on the mounting piece 10 so as to fit into the recessed hole 17 of the side plate 8.

In such a configuration, the workpiece side member 4 is normally held pressed against the contact surface of the support member 3 by positioning by the spring force of the elastic body 13 and the engagement of the tapered protrusion 18. For example, as shown in FIG. When the support member 3 moves, the unillustrated tip of the workpiece side member 4, for example, the tip of the welding torch 2, comes into contact with an external fixed part, and when an external force is applied to the workpiece side member 4 in the direction of arrow M1, the workpiece side member 4 Frame body 7
It tilts with the lower contact part A□ as a fulcrum.

Therefore, the slide shaft is tilted via the spherical bearing 11 and retreats in the direction of arrow B against the elastic body 13, and the dog 16 rotates to open (or close) the limit switch 15, and the robot Stop immediately or return in the opposite direction to eliminate contact with the fixed part.

Next, as shown in FIG.
When an external force in the direction is applied, the workpiece side member 4
The slide shaft 12 is tilted about the upper contact portion A2 as a fulcrum, and the slide shaft 12 slides in the direction of arrow B against the tilted elastic body 13 in the opposite direction to that shown in FIG. 4, thereby operating the limit switch 15.

In addition, an external force M3 is applied to the workpiece side member 4 in a direction perpendicular to the paper surface of FIG. 4 or in a rotational direction with respect to the slide shaft axis.
is applied, the tapered protrusion 18 of the mounting piece 10 disengages from the recessed hole 17 provided in the side plate 9 and rides on the side plate 9, and the workpiece side member 4 tilts in the same way as when the external force M□ is applied, and the external force M1 The slide shaft 12 is moved backward and the limit switch 15 is operated in the same way as in the case of .

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 perpendicular to the plane 20 and passes through the center of rotation of the spherical bearing, the component force will be equal to any of the above cases, tilting the workpiece side member and operating the limit switch 15. Can be done.

In addition, the present invention may be such that the dog 16 is attached to the limit switch 15 as shown in FIG. It may be provided in a conical shape or in an arc shape centered on the slide shaft axis.

Further, a coil spring, rubber, or the like may be used for the elastic body 13.

In this way, the workpiece side member is attached to the support member that moves, and the workpiece side member is brought into contact with the contact surface, and the slide shaft attached to the other member is slid on the spherical bearing attached to one member. The contact surfaces of both members are pressed against each other by an elastic body inserted into the slide shaft, and a concave hole and a tapered protrusion that engages with the concave hole are provided on this contact surface, so that the workpiece side member When it hits another fixed part, the contact surface tilts against the elastic body and the slide shaft is deflected, and this deflection operates a limit switch. When an external force that exceeds a certain value is applied to the workpiece side member during operation, the elastic body of the connecting part cushions the impact and causes the slide shaft to deflect, opening (or closing) the limit switch and preventing the robot from operating. It is possible to take protective measures such as stopping the system 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. No need for teaching.

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. The contribution it makes to industry is extremely large.

[Brief explanation of the drawings] 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. 4 and 5 are side sectional views for explaining the operation, and FIG. 6 is a side sectional view showing another embodiment of the present invention. 1 is a robot body, 2 is a welding torch, 3 is a support member, 4
is a work 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 is a slide shaft,
13 is an elastic body, 14 is a nut, 15 is a limit switch, 16 is a dog, 17 is a recessed hole, 18 is a tapered projection, 21
is a rotating ball, and 22 is a screw.

Claims (1)

[Scope of utility model registration request] A support side member and a workpiece side member are connected via a spherical bearing attached to one member and a slide shaft attached to the other member and supported so as to be able to slide in the axial direction on the spherical bearing. , an elastic body that presses the contact surfaces of the two members against each other is fitted into the slide shaft, a recessed hole is provided on one of the contact surfaces of both members, and a tapered protrusion that engages with the recessed hole is provided on the other contact surface. , an external contact detection device characterized by comprising a limit switch operated by the deflection of a slide shaft.