JPH07122446B2 - Safety fittings - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a safety joint suitable for preventing damage to a robot hand when the robot hand is overloaded due to impact or the like.

(Prior Art) Conventionally, various safety measures have been taken in preparation for an unexpected situation that occurs during the operation of a robot. For example, when the hand is overloaded due to some impact, the robot is brought to an emergency stop to ensure the safety of the worker and prevent the robot from being damaged.

As a means for this, due to overload that occurs in the hand, this hand is designed to come off the arm, or the hand is attached to the arm via a member that is easily broken or deformed, and this is overloaded. This is because, when the robot breaks or deforms when it occurs, the limit switch or the like is operated to stop the operation of the robot.

(Problems to be Solved by the Invention) However, various inconveniences have been caused by such means. For example, in an apparatus in which the hand is disengaged from the arm when an overload occurs, a secondary accident may occur after the hand is disengaged, and the positioning and mounting at the time of remounting the hand Is difficult to adjust, and in a device in which the hand is attached to the arm via a member that easily breaks or a member that easily deforms, the member must be replaced every time the member breaks or deforms. However, the work for this is not only troublesome, but also a large time loss is caused, and the cost of replacement is high because of the high unit price of this member.

The present invention has been made in view of the above circumstances, and aims at ensuring the safety of the operator during the operation of the robot, preventing damage to the robot, and even when the robot stops at the time of abnormality,
It is an object of the present invention to provide an improved safety joint that enables repair work of a robot to be performed easily and in a short time and at low cost, and to continue the operation of the robot promptly.

(Means for Solving the Problems) In order to solve the above-mentioned conventional problems, the safety joint of the present invention includes a pair of holding members that hold the coil spring from both ends, and both holding members can swing with respect to each other. And a sensor that is fixed by a positioning member that breaks or deforms when an overload occurs, and that is activated when the positioning member breaks or deforms.

(Operation) As described above, in the safety joint of the present invention, both holding members are connected and fixed by the positioning member during normal use, and function as an integral joint. When the safety joint is overloaded and the positioning member is broken or deformed, the coil spring acts to absorb and relax the overload from the time when this state is detected to when the sensor is activated. Plays a role as a member.

According to such a configuration, even if the positioning member is broken, both holding members maintain the connected state while holding the coil springs from both ends, and the safety joint can flexibly deform the coil spring against overload, Only the positioning member is damaged when an overload occurs, and unlike conventional safety joints, the repair work can be easily and quickly performed without damaging the joint body.

(Example) Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

1 is a side view showing an embodiment of a safety joint according to the present invention, and FIG. 2 is a top view of the safety joint shown in FIG.
3 is a perspective view of an intermediate joint provided in the safety joint shown in FIG. 1, FIG. 4 is a perspective view showing a positioning member of the safety joint shown in FIG. 1, and FIG. 5 is this embodiment. 11 is a perspective view of a robot showing an application example of the safety joint of FIG.

As shown in FIGS. 1 and 2, the safety joint 1 of this embodiment
Includes a first holding body 3 and a second holding body 4 that hold four coil springs 2 from both ends, and these holding bodies are connected by a spherical bearing 6.

The spherical bearing 6 has a spherical portion on the first holding body 3 side to swingably connect the first holding body 3 and a bolt tightening portion 7 on the second holding body 4 side. This allows the second holding bodies 4 to be connected together and the distance between the holding bodies to be adjusted. Then, between the first holding body 3 and the second holding body 4, four coil springs 2 concentrically centering on the spherical bearing 6 and having a somewhat large elastic force are interposed. The coil spring 2 is attached to the first and second holders.
This can be done by fitting the coil spring 2 into the concave grooves 5 provided at the respective facing positions of 3 and 4 and having a certain depth. A compression spring is used as this coil spring, and an appropriate elastic force is exerted on each coil spring 2 by adjusting the interval between the first and second holding bodies 3 and 4 in the bolt tightening portion 7 of the spherical bearing 6. To be done. As a result, the first holding body 3 and the second holding body 4 can be flexibly behaved with respect to each other.

Further, the first holding body 3 and the second holding body 4 are fixed to each other by the positioning plate 9.

As shown in FIG. 4, the positioning plate 9 has first and second positioning plates.
The holders 3 and 4 are fitted into the recesses provided in the holders 3 and 4, and are fixed by a detachable method such as fastening with bolts. In the figure, 20 is a bolt hole provided in the positioning plate 9, and 11 is a screw hole provided in each of the holding bodies 3 and 4. With such a positioning plate 9, the positioning of the first and second holding bodies 3 and 4 can be performed easily and accurately. Further, the positioning plate 9 has some elastic force,
Further, it is formed of a steel strip having a strength such that it breaks or bends when overloaded. As shown in FIG. 2, such a positioning plate 9 is provided on each of two adjacent side portions of each holder 3 and 4, whereby the coil spring 2 is provided.
The expansion and contraction of the arm is suppressed and the safety joint 1
It can function as a connecting member with 16.

Further, between the first and second holding bodies 3 and 4, for example, a position detecting sensor 10 such as a limit switch which is fixed to the first holding body 3 and in which the operator is brought into contact with the second holding body. Is attached. The position detecting sensor 10 operates when the safety joint 1 is overloaded and the positioning plate 9 is broken or bent, and can stop the operation of the robot in an emergency.

Further, the safety joint 1 is provided with an intermediate joint 13 as a double measure against a load much larger than the breaking of the positioning plate 9. This intermediate joint is provided between the first holding body 3 and the free end of the arm 17 and is made of hollow aluminum casting. As shown in FIG. A circumferential groove 14 is provided in the circumferential direction,
When a larger overload that breaks or deforms the positioning plate 9 is generated, stress is concentrated at the position of the circumferential groove 14 and the positioning plate 9 is broken. In the figure, 15 indicates a bolt tightening position of the intermediate joint 13.

As shown in FIG. 5, the safety joint 1 configured as described above is interposed between the hand 16 and the free end of the arm 17 by means such as bolt fastening.

Next, the operation of the safety joint 1 will be described. For example, when the robot is moving a box loaded on a pallet to another pallet, and the box before the move is displaced from the predetermined position for some reason or is placed diagonally. Moreover, the robot tries to perform work according to a predetermined program. When such an unexpected situation occurs, the hand 16 is overloaded and the safety joint 1 according to the present invention works to prevent damage to the robot. That is, when the hand 16 is overloaded due to an impact or the like, this load is transmitted to the second holding body 4 as it is. Then, first, the positioning plate 9 is deformed or broken by this overload.

Here, when the positioning plate 9 is bent, the first holding body 3 and the second holding body 4 are displaced from their original relative positions, and at this time, the sensor 10 operates and the robot stops. In such a case, the second holding body 4 does not separate from the first holding body 3, and therefore the hand 16 does not drop. In addition, regarding the restoration of the safety joint 1 in this case,
All that is required is to replace the positioning plate 9.
Can be mounted by fitting them into the recesses provided on the sides of the first and second holding bodies 3 and 4 and tightening them with bolts, so repair work for this can be performed easily and quickly at low cost. .

In addition, even when the positioning plate 9 is broken due to overload, the second holding body 4 has a spherical axis 6 with respect to the first holding body 3.
Therefore, the second holding body 4 does not separate from the first holding body 3 because the connection state can be maintained. In this case, the positioning plate 9 may be repaired only by replacing the positioning plate 9 as described above.

The safety joint of the present invention can be used not only between the robot arm and the hand as described above, but also as a safety joint for other devices within the range of its function. Further, if the above-mentioned intermediate joint is provided according to the usage situation, it is convenient to take double safety measures.

(Effect of the Invention) As described above, according to the safety joint of the present invention, when the robot hand is overloaded due to an external impact or an unexpected situation, only the positioning plate is damaged or deformed. Yes, the safety fitting body is not damaged in any way.
Further, when the positioning plate is damaged or deformed, the sensor immediately operates to stop the robot, and repair of the safety joint can be started. Moreover, as described in detail, this repair can be performed simply and quickly by replacing the positioning plate, can be easily and quickly performed at low cost, and the time required to restart the robot can be shortened.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of a safety joint according to the present invention,
FIG. 2 is a top view of the safety joint shown in FIG. 1, and FIG.
4 is a perspective view of an intermediate joint provided in the safety joint shown in FIG.
FIG. 1 is a perspective view showing a positioning plate of the safety joint shown in FIG.
FIG. 5 is a perspective view of a robot showing an application example of the safety joint of this embodiment. 1 ... Safety joint 2 ... Coil spring 3 ... First holding body, 4 ... Second holding body 6 ... Spherical bearing, 9 ... Positioning plate 10 ... Sensor, 13 ... Intermediate joint 14 ... … Circumferential groove, 16 …… Hand 17 …… Arm

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsugio Nakamoto 4-14-12 Koishikawa, Bunkyo-ku, Tokyo Kyodo Printing Co., Ltd. (56) Bibliographic references Sho 61-148587 (JP, U)

Claims (5)

[Claims] 1. A pair of holding members for holding a coil spring from both ends, both holding members being swingably connected to each other, and fixed by a positioning member that breaks or deforms when an overload occurs, and further this positioning is performed. A safety joint comprising a sensor that operates when a member breaks or deforms. 2. The safety joint according to claim 1, wherein the coil spring is a compression spring. 3. The means for connecting the pair of holding members to each other comprises a spherical bearing having a spherical surface portion at least at one end and bolted at the other end. Safety fittings. 4. An intermediate member which is formed of a hollow body in the holding member and is provided with a circumferential groove portion for cutting when a load larger than an overload for breaking or deforming the positioning member is applied in a circumferential direction on the outer circumference. The safety joint according to claim 1, wherein the joints are connected. 5. The positioning member is attached by fitting into concave grooves provided in each of the pair of holding members and tightening with bolts. Safety joint described in paragraph.