JPS6337188Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an improvement of a safety device for a work robot.

(Prior Art) Various tasks are increasingly being performed by work robots, and for example, a certain person is required to grasp a workpiece at a predetermined position and transport it to a processing position using its working part. Contact will take place. Generally, the working part of the work robot approaches the workpiece by making a predetermined movement, but if the workpiece is misaligned, for example,
Unreasonable force is applied to this working part, leading to damage to the workpiece or the working robot.

For this reason, conventionally, a head section having a working section is attached to the robot body via a joint member, and this head section is made to be able to swing 360 degrees around the central axis of the joint member. Displacement with respect to the main body is detected, and if the amount of displacement exceeds a predetermined value, it is determined that there is an abnormal approach, that is, an unreasonable contact with the work, and the position of the work is inspected or the head section is reapproached to the work. In order to detect the displacement of the head section, a limit switch has been used for reasons of cost and structural simplicity. That is, a limit switch whose contact operates in a 360° direction is used to detect displacement of the head portion relative to the robot body around the central axis of the joint member above a predetermined value.

However, with conventional limit switches,
Although it is possible to sense the entire 360° circumference around the center axis of the joint member in the head, displacement in the direction of this center axis cannot be detected, and the abnormal approach of the head to the workpiece in this direction cannot be detected completely. There were some drawbacks that I can't say.

In order to solve the above-mentioned problems, Japanese Utility Model Application Publication No. 50-183390 discloses a device that uses a single limit switch to detect displacements of the head section relative to the robot body that exceed a predetermined value in all directions. has been disclosed.

The device described in the above publication is based on the premise of using a limit switch that is actuated by the stroke movement of a probe, and has a plate-shaped actuator that is supported in a floating manner and is made to face the probe so that it can come into contact with it. Meanwhile, a holder arm as a head is attached to a tool holder body provided on a robot body so that it can move freely in its axial direction and swing freely. And between the peripheral edge of the actuator and the holder arm,
The actuator has a plurality of ferrules spaced apart from one another in the circumferential direction.

With the above configuration, the displacement of the holder arm around the axis of the tool holder body and in the axial direction is
This appears as a tilt of the actuator, and the limit switch is activated when the actuator tilts more than a predetermined value.

(Problems to be solved by the invention) However, the invention described in the above-mentioned publication causes various problems as follows.

First, the entire device for detecting displacement becomes complicated and large.

In addition, the holder arm must not only be able to swing relative to the robot body, but also be capable of stroke movement, which may require major modifications to the robot itself or limit the range of robots to which it can be applied. This will result in In addition to this, the robot body and head part (holder arm) are
This makes it difficult to secure a firm connection with the robot, which is disadvantageous in terms of ensuring the accuracy of the robot's work.

Furthermore, since the limit switch feeler must necessarily be located approximately on the axial extension of the tool holder body, the placement positions of other parts are also inevitably constrained, which reduces the freedom of placement. is also disadvantageous.

In addition to the above, since the detector is in contact with the peripheral edge of the floating-supported actuator, and the contactor is in contact with the vicinity of the center of the actuator, the stroke movement of the detector is The stroke movement of the tentacle becomes smaller. This is also disadvantageous in terms of improving detection accuracy. This detection accuracy becomes even more unfavorable if it is also proposed that it is difficult to secure the connection between the robot body and the holder arm.

Therefore, it is an object of the present invention to solve the various problems mentioned above at once, and to detect a swing displacement and an axial displacement of the head section relative to the robot body in excess of a predetermined value using a single limit switch. The purpose of the present invention is to provide a safety device for a working robot.

(Structure and operation of the invention) In order to achieve the above-mentioned object, the present invention has the following structure. That is, in a working robot in which a head section having a working section is swingably supported with respect to the robot main body via a joint member, a rod-shaped contactor is attached to either the robot main body or the head section. A limit switch operated by tilting is provided apart from the joint member, and a boss member loosely fitted to a rod-like contact of the limit switch is provided on the other side, and the rod-like contact has each end face of the boss member. A pair of said members are provided so as to sandwich the boss member at a predetermined distance from each other. The limit switch is configured to include a one-piece contact portion that tilts the bar-like contact of the limit switch when the limit switch comes into contact with a member.

With this configuration, in the case of an abnormal approach of the head part in a direction that intersects the center axis of the joint member, the boss member itself displaces the contact of the limit switch, and the abnormality from the direction of the center axis is detected. In the approach, the boss member is displaced in a direction transverse to the central axis via an abutment member that functions as a kind of inclined cam, whereby the limit switch can be actuated in both cases.

(Example) An example of the present invention will be described below based on the attached drawings.

In FIG. 1, a robot body 1 is fixed to a robot arm 2. As shown in FIG. The head portion 3 is capable of swinging 360° around the central axis α of the joint member 5 via a joint member 5 installed at the center of the upper substrate 4 located at the lowest part of the robot body 1. It is supported by the robot body 1. Furthermore, three sets of spring seats 7a and 7b are mounted oppositely to each other at equal intervals around the central axis α on the lower substrate 6 located at the top of the head portion 3 and the upper substrate 4. A spring 8 is interposed between the seats 7a and 7b, respectively, and acts on a force to separate the head portion 3 from the robot body 1, so as to maintain the head portion 3 in a fixed position relative to the robot body 1. The head section 3 is equipped with a hand 9 as a working section and a drive motor 16 for opening and closing the hand 9.

With the above-described configuration, when the hand 9 of the head section 3 collides with the work from the side,
The head portion 3 swings around the joint member 5 by compressing the spring 8, thereby providing a buffer to prevent the hand 9 from being damaged. Similarly, when the hand 9 collides with the workpiece from above and below, the center axis α by the joint member 5 set in advance
Since there is directional wobbling, the spring 8 also buffers it in this case.

However, if the above-mentioned collision force is large and exceeds the swinging range of the head portion 3, there is a risk that the hand 9 may be damaged. In order to prevent such dangers, that is, damage to the work robot and workpiece,
Excessive displacement of the head section 3 is detected using a limit switch, and damage to the hand 9 is prevented by processing such as cutting off the power source based on the signal. The limit switch part will be explained with reference to FIG. 2 and below. As shown in FIG.
a is in the shape of a rod, and is capable of swinging motion about a fulcrum 10b, and is configured so that the contact point is switched when the inclination of the axis exceeds a predetermined amount;
The structure is such that displacement can be detected over the entire 360° circumference in the direction perpendicular to 0a, but displacement in the axial direction cannot be detected.

As shown in FIG. 2, the limit switch 10 described above is fixed to the upper substrate 4 via a mounting plate 11 with its axial direction facing up and down, that is, parallel to the central axis α. .
On the other hand, a boss member 12 is attached to the head portion 3 via an attachment member 13. This boss member 1
2 is fitted to the contact 10a of the limit switch 10 with a predetermined gap therebetween. Therefore, if for some reason the hand 9 strongly collides with the workpiece in the lateral direction, that is, in the direction intersecting the central axis α, the head portion 3 will swing significantly around the joint member 5. do. As a result, the boss member 12 fixed to the head portion 3
is displaced in the direction perpendicular to the axis with respect to the feeler 10a, and the limit switch 10 is operated. This results in
As in the conventional case, abnormal approach of the head section 3 to the workpiece from the lateral direction is detected.

Here, in the present invention, as shown in FIGS. 3 and 4, a pair of upper and lower contact members 14 having sloped surfaces are provided on both sides of the boss member 12 at an appropriate distance. . This contact member 14 is connected to the boss member 1
It is sufficient that the limit switch 10 is fixed to the contact 10a of the limit switch 10 in an inclined state so as to make partial contact with the end face of the limit switch 10, and the screw 15 is fixed as shown in FIG.
Even a collar-like one fixed with a
As shown in the figure, it may be something like a washer adhered to the tentacle 10a. By providing such a contact member 14, the hand 9 of the head portion 3
When the contact member 14 approaches the workpiece abnormally in the vertical direction, that is, in the direction of the central axis α, the contact member 14 contacts the end face of the boss member 12 in a state where it is in partial contact (contacts only a part of the circumferential direction of the boss member 12). So,
The boss member 12 is eventually displaced in a direction intersecting the contactor 10a, and the limit switch 10 is actuated. In this way, abnormal displacement of the head portion 3 in the direction of the central axis α is also detected by the limit switch 10. That is, in the embodiment, the portion of the inclined abutment member 14 closest to the end surface of the boss member 12 is used as the one-side abutment portion.

In the present invention, the limit switch 10 is disposed on the robot body 1 side, and the boss member 12 is disposed on the head portion 3 side, but this attachment relationship may be reversed. Alternatively, the end surface of the boss member 12 may be an inclined surface that is inclined with respect to the contact member 10a, and the contact member 14 may be attached in a direction perpendicular to the contact member 10a. Further, since the boss member and the abutment member only need to make one-sided contact, instead of the above-mentioned inclination, the one-side contact portion may be formed by, for example, forming a protrusion on a part of the end face of the boss member in the circumferential direction. .

(Effects of the invention) As is clear from the above, the invention has the following effects:
Abnormal displacement of the head section from any direction can be detected by using just one limit switch, so safety in preventing damage to the robot or workpiece can be greatly improved without requiring large costs.

In addition, the structure is simple and the overall size can be made small, and a high degree of freedom in arrangement can be obtained.

Furthermore, since the robot body and the head need only be connected so that they can swing like in the past, it can be retrofitted to existing robots, making it extremely versatile. becomes.
Of course, the fact that only the above-mentioned swinging movement is required is preferable in terms of minimizing rattling at the joint between the robot body and the head and ensuring the accuracy of the robot's work.

Furthermore, since the limit switch is provided apart from the joint member, the swinging motion of the head relative to the robot body is sufficiently magnified and transmitted to the contact of the limit switch, which is preferable from the point of view of improving detection accuracy. Become something.

[Brief explanation of the drawing]

Fig. 1 is an external view of the main parts of a work robot according to an embodiment of the present invention, Fig. 2 is a view taken in the direction of arrow A in Fig. 1, Fig. 3 is a sectional view of the main parts of Fig. 2, and Fig. 4 is FIG. 7 is a cross-sectional view of a main part showing a modified example near the boss member. 1...Robot body, 3...Head part, 5...
Joint member, 9...Hand (working part), 10
...Limit switch, 10a...Toucher, 12...
...Boss member, 14...Abutment member.

Claims (1)

[Claims for Utility Model Registration] A working robot in which a head portion having a working portion is swingably supported with respect to the robot main body via a joint member, wherein either the robot main body or the head portion A limit switch operated by the tilting of a rod-like contact member is provided on one side, separated from the joint member, and a boss member loosely fitted on the rod-like contact member of the limit switch is provided on the other side, and the rod-like contact member includes: A pair of said members are provided with respect to each end face of said boss member and are arranged to sandwich said boss member at a predetermined interval, and one of said abutting member and said boss member facing each other has a A safety device for a work robot, comprising: a contact portion that tilts a rod-like contact of the limit switch when the contact member and the boss member come into contact with each other.