JPH0413597A - Protection mechanism for overload of robot arm - Google Patents

Abstract

PURPOSE:To evade the danger of a driving mechanism or human body, by providing a detection sensor which detects that the engagement of engaging elements is released with the overload in the vertical or rotating direction applied on a robot arm between a bracket and the robot arm. CONSTITUTION:The rotation force of a rotating shaft 2 is transmitted to a robot arm 3 by the engagement of the engaging elements 8 provided between the bracket 7 fixed to the rotating shaft 2 and the robot arm 3. This engagement is performed with the metal ball 8d of a locking part 8c being fitted into the hole 8b of a perforated plate 8a with its being pressed by a spring 8e. Only if any overload is applied on the robot arm 3, the engagement is released with the metal ball 8d being deviated from the hole 8b of the perforated plate 8a and the robot arm 3 becomes free. The release of this engagement is detected by a detection sensor 9 and a driving mechanism is stopped by a separate mean with the detection signal thereof and the robot arm is freely rotated for the bracket, in the case of the overload being in the rotating direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a protection mechanism against overload applied to a robot arm.

[Background Art] In recent automatic machines, robot mechanisms are often used to transport workpieces. FIGS. 2(a) and 2(b) are conceptual diagrams of a robot mechanism used to transport a disk to be inspected in a magnetic disk inspection apparatus.

Figure (a) shows a plan view, and figure (b) shows a side view. The side of the robot is composed of a rotating shaft 2 provided on a drive mechanism 1 that moves and rotates up and down, and a robot arm 3 fixed to the rotating shaft 2 and having a suction part 4 at its tip. The disk 5 to be inspected, which is attracted to the suction unit 4, is placed between the upper and lower parts of the robot arm 3.
It is transported from the storage position to the inspection section 6 by rotational movement, and is mounted on the spindle 6a. After the inspection has been completed, the disk is sucked again by the suction section 4 and transported to another inspection section or storage position.

[Problem to be solved] In the above robot mechanism, the robot arm is a simple one that simply moves up and down and rotates, but even with such a mechanism, the above-mentioned disk transport itself is simple, so the transport operation is That's enough.

However, since it is simple, no measures are taken in case an abnormality occurs. For example, some external force may be applied to the robot arm while it is moving, and if this is large, the arm itself or the drive mechanism 1 will be damaged. Furthermore, if the external force is caused by the human body, that person may be injured. Robotic mechanisms need at least some protection to detect such overloads and stop operation, avoiding damage or injury.

The present invention has been made in view of the above, and an object thereof is to provide a mechanism for detecting and protecting an overload applied to a robot arm.

[Means for Solving the Problems] The present invention provides a robot that moves vertically and rotationally by a drive mechanism, attracts a magnetic disk to be inspected to a suction section provided at its tip, and transports it between predetermined positions of an inspection device. This is an overload protection mechanism in the arm.

The robot arm is freely rotatably attached to the rotating shaft that moves up and down/rotates the drive mechanism, and the bracket is fixed to the rotating shaft. The bracket (!:0) is engaged between the bond arms by an engager that disengages due to overload, thereby transmitting the rotational force of the rotating shaft to the robot arm.

A detection sensor is provided between the bracket and the robot arm to detect disengagement of the engager due to overload applied to the robot in the vertical and rotational directions.

The engager described above consists of a hole plate fixed to the robot arm,
It consists of an engaging T part that is provided on the bracket and has a metal ball that is inserted into a groove and urged outward by a spring, and a part of the metal ball is inserted into the hole in the hole plate, resulting in the engagement described in "-". This causes the metal ball to deviate from the hole in the hole plate and become disengaged due to overload. Additionally, a hinge is provided that allows the robot arm to bend upward in response to an upward overload on the robot arm.

[Operation] In the robot arm overload detection mechanism with the above configuration, the rotational force of the rotating shaft is transmitted to the robot arm by the engagement of the engager provided between the bracket fixed to the rotating shaft and the robot arm. Ru. This engagement is achieved by the metal ball of the locking part being pressed by a spring and fitting into the hole of the hole plate. The robot arm becomes free as it deviates further and is disengaged. This disengagement is detected by a detection sensor, and the drive mechanism is stopped by a separate means based on the detection signal.

If the overload is in the rotational direction, the robot arm will rotate freely relative to the bracket; if the overload is in the -L direction, the robot arm will bend upwards due to the hinge, and in either case, damage to the drive mechanism or Danger to humans is avoided.

[Embodiment] FIGS. 1(a) and 1(b) are cross-sectional views of an embodiment of the overload protection mechanism for a robot arm according to the present invention, and FIG.
), (b) are vertical cross-sectional views (N is a horizontal cross-sectional view of the engager. In Figure (a), the rotating shaft 2 is moved up F by the drive mechanism and rotates at the same time. A ring 2a is attached to the rotating shaft 2. The robot arm 3 is fitted and inserted freely to rotate, and the robot arm 3 is fixed thereto.A suction part 4 is attached to the tip of the robot arm 3 in the same way as before.The robot arm 3 is also cut near the base to attach the hinge 3.
a to make it possible to bend upward. On the other hand, the bracket 7 is fixed to the rotating shaft 2, and the robot arm 3 is connected to the bracket 7.
An engaging element 8 is provided between them. Using the figure (b) together, the engager 8
To explain this, a hole plate 8a having holes 8b is fixed to the robot arm 3, and a locking part 8c is fixed to the bracket 7, respectively. The engaging part 8C is a spring 8 fitted into a groove.
e, and a metal ball 8d that is urged outward by this, and is normally pressed by a spring 8e and the metal ball 8d
A part of the hole plate 8a is fitted into the hole 8b, and the hole plate 8a and the engaging portion 8C are engaged with each other. Due to this engagement, the rotational force of the rotating shaft 2 is transmitted to the robot arm 3. Further, a detection sensor 9 is provided between the robot arm 3 and the bracket 7 to detect disengagement. 9a is a light source and 9b is a light receiving sensor. However, the detection sensor 9 is not an optical type, and other means such as a limit switch may be used. Further, the mounting position is not necessarily limited to the illustrated position, but a required number of the mounting parts may be arranged at a position where disengagement in the vertical direction and rotational direction can be detected satisfactorily. Now, if some external force is applied to the robot arm 3 and an overload occurs, the metal ball 8d will deviate from the hole 8b in the direction of rotation or in the direction of rotation according to the direction of the external force, and the engagement will be disengaged, causing the robot arm 3 to become free. At the same time, this is detected by the detection sensor 9, and the drive mechanism is separately stopped based on the detection signal. In the above, the reason why the two holes 8b1 and the metal balls 8d are provided facing each other is to ensure stable and reliable engagement.

[Effects of the Invention] As is clear from the above explanation, in the robot arm overload detection mechanism according to the present invention, the rotational force of the rotating shaft is applied to the robot arm by the engagement of the metal ball fitted into the hole of the hole plate. If any overload is applied to the robot arm, the metal ball will deviate from the hole and become disengaged, and this will be detected by the detection sensor and the drive mechanism will be stopped, and the overload will stop rotating. If the overload is in the direction, the robot arm will rotate freely; if the overload is in the - direction, the robot arm will bend upwards due to the hinge, and in both cases, danger to the drive mechanism or human body will be avoided. The effect of contributing to the protection of robot mechanisms and human bodies from danger is significant.

[Brief explanation of drawings]

FIGS. 1(a) and (b) are structural cross-sectional views of an embodiment of the overload protection mechanism for a robot arm according to the present invention, and FIGS. 2(a) and (b) are a disk transport robot in a magnetic disk inspection device. It is a conceptual diagram of the side of the machine. DESCRIPTION OF SYMBOLS 1... Drive mechanism, 2a... Ring, 3a... Hinge, 5... Disc, 7... Bracket, 8a... Hole plate, 8C... Retainer part, 8e... Spring, 2... Rotating shaft, 3... Robot arm, 4... Adsorption section, 6... Inspection section, 8... Engagement element, 8b... Hole, 8d... Metal ball, 9...Detection sensor.

Claims (3)

[Claims] (1) In a robot arm that moves up and down/rotation by a drive mechanism, attracts a magnetic disk to be inspected to a suction part provided at its tip, and transports it between predetermined positions of an inspection device. The robot arm is rotatably attached to a rotating shaft, a bracket is fixed to the rotating shaft, and the bracket and the robot arm are engaged with each other by an engagement element that disengages due to overload. transmits the rotational force to the robot arm, and detects that the engagement element is disengaged due to an overload applied to the robot arm in the vertical direction or rotational direction between the bracket and the robot arm. An overload protection mechanism for a robot arm, characterized by being equipped with a detection sensor. (2) It consists of a hole plate fixed to the robot arm, and a locking part that is provided on the bracket and has a metal ball that is fitted into a groove and biased outward by a spring. 2. The engaging element according to claim 1, wherein the metal ball is fitted into the hole of the hole plate to achieve the engagement, and when the overload occurs, the metal ball deviates from the hole of the hole plate and the engagement is removed. Overload protection mechanism for robot arm. (3) The overload protection mechanism for a robot arm according to claim 1, further comprising a hinge capable of bending the robot arm upward in response to an upward overload on the robot arm.