JPH0258074B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a hand device for an industrial robot, and more particularly to a small hand device that can obtain a large gripping force with a small drive device.

[Prior art]

Conventional hand devices for industrial robots generally have a gripper fixedly attached to the left and right arms facing each other, and the left and right grippers are moved close to each other by driving these arms using a rack and pinion system.・It was meant to separate people. Therefore, it is necessary to guide the arms while keeping them parallel, which not only complicates the configuration, but also applies a bending moment to the arms, which is inconvenient for obtaining a large gripping force.

[Summary of the invention]

The present invention has been made to eliminate the above-mentioned drawbacks, and by displacing the gripping claws provided around the rotary cam so as to be expandable and retractable, the present invention can be easily and miniaturized, and has a large gripping force. The present invention aims to provide a hand device for an industrial robot having the following features.

The hand device for an industrial robot according to the present invention includes:
It is rotated by a main body fixed to the tip of the robot arm and a drive device housed in this main body.
a rotating cam having a plurality of slopes forming an inclined profile;
A plurality of gripping claws are disposed within the rotation plane of the rotating cam, one end is pivotally connected to the main body by a shaft, and the other end has a workpiece gripping portion on one side, and the other end of the gripping claws is fixed to the other side with a screw. The shaft is rotatably fitted into the shaft having an eccentric screw hole and the shaft having an eccentric screw hole. The rotary cam is characterized by comprising a roller that swings radially to expand and contract within the rotational surface of the rotary cam around a side shaft, and a holding means that holds the roller in constant contact with the slope of the rotary cam. That is.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an overall side view of an industrial robot according to the present invention. In the figure, 1 is the main body of the industrial robot, 2 is an elevating body that is supported by this main body 1 and reciprocates linearly in the vertical direction, and 3 is an elevating body. A first arm 4 is supported at the tip of the first arm 3 and rotates back and forth on a horizontal plane, and a second arm 4 is supported at the tip of the first arm 3 and rotates back and forth on a horizontal plane.
The arm 5 is a hand device that is fixed to a rotation shaft 6 perpendicular to the tip of the second arm 4 and rotates back and forth around the rotation shaft 6, and is the object of the present invention. The configuration of this hand device 5 is shown in more detail in FIG. 2 and subsequent figures. Reference numeral 7 denotes a workbench, on which a cylindrical workpiece 8 is placed.

FIG. 2 shows one embodiment of the present invention.
It is an enlarged sectional view of the part shown in the figure. In the same figure, 9
is a main body fixed to the lower end of the rotating shaft 6, and a driving device 11 for rotating the cam 10 is housed inside the main body. The cam 10 is provided below the lower surface of the main body 9 via the rotating shaft 12. Reference numeral 13 denotes a plurality of gripping claws disposed so as to circumscribe the cam 10, and the base of each gripping claw 13 is pivotally connected to the main body 9 by a shaft 14.

The shape of the cam 10 and the shape and arrangement of the gripping claws 13 that are rotated in contact with the cam 10 are clearly shown in FIG.

A gripping part 15 that contacts the inner surface of the cylindrical workpiece 8 is provided at the tip of each gripping claw 13, and a roller 16 that rotates in contact with a cam 10 is mounted on a shaft at the corner opposite to this gripping part 15. It is pivoted at 17. The cam 10 is located in the contact area of the gripping pawl 13 with the roller 16, that is, in the operating area of the gripping pawl 13, as shown in FIG.
The radial dimension from the center O of the cam 10 is formed to gradually increase from point b (the most convex part of the cam profile) to point b (the most convex part of the cam profile).

The roller 16 of the gripping claw 13 touches the slope 18 of the cam 10
In order to maintain constant contact with the cam 10 and the roller 16, both the cam 10 and the roller 16 are preferably made of iron, and one of them is preferably magnetized. Alternatively, a torsion spring (not shown) that biases the roller 16 in the contact direction may be installed between the gripping claw 13 and the main body 9.

When the gripping claws 13 are pivotally connected to the main body 9 by the shaft 14, the gripping claws 13 can be pivoted so that they can rotate freely, but the gripping claws 13 may be frictionally tightly fitted to the shaft 14 to prevent the workpiece from being moved. It is appropriate to prevent the gripping claws 13 from wobbling during the gripping operation.

Next, in order to be able to adjust the workpiece gripping dimensions,
A shaft 17 for pivotally supporting the roller 16 is formed to have an eccentric shaft portion 19, as shown in the partially enlarged view of FIG. That is, the roller 16 is rotatably fitted to the eccentric shaft portion 19, and the shaft 17 is tightly pivoted to the gripping claw 13 due to friction. and axis 1
A rotation groove 20 is provided at the outer end of the shaft 1, and a tool such as a screwdriver (not shown) is inserted into this groove 20 to rotate the shaft 1.
7 is rotated appropriately, the amount of movement of the roller 16 in and out of the gripping claw 13 changes depending on the rotational position of the eccentric shaft portion 19, so that the dimension between the center O of the cam 10 and the gripping portion 15 can be adjusted as desired. be able to.

In order to grip a cylindrical workpiece 8 using the hand device 5 according to the present invention configured as described above, the hand device 5 is brought directly above the workpiece 8 by controlling its position, and then inserted into the workpiece 8. (Second
(see figure). Next, when the drive device 11 rotates the cam 10 by a predetermined angle in the direction of arrow A in FIG.
4, the envelope circle 21 of each gripping part 15 expands concentrically to match the inner diameter of the workpiece 8, and is strongly pressed by each gripping part 15.

Now, considering the gripping force by the gripping claws 13,
As shown in FIG. 6, the gripping force is P, the rotational force of the cam 10 is F, the force pushing up the roller 16 along the cam slope 18 is F ₁ , and the inclination angle of the cam slope 18 is θ.
Then, P=F/tanθ, and when setting θ=5°, from the above formula, P≒
It will be on the 12th floor. However, 22 is an axis directed toward the center of the cam 10.

In this way, the gripping force P can be increased to about 12 times the rotational force F of the cam 10, and the workpiece 8 can be gripped strongly. Moreover, the grip part 15
The roller 16 is placed on the straight line connecting the center O of the cam 10 and
Since the gripping claws 13, rollers 16, cam 10, etc. are under the action of compressive force, almost no bending moment is applied to them, so that even if they are miniaturized, they are safe in terms of strength. Further, as is clear from the above equation, the upper limit of the inclination angle θ that can increase the gripping force P by one or more times with respect to the rotational force F is 45°. That is, when θ=45°, the rotational force F and the gripping force P become equal (P=F). Therefore, the inclination angle θ
should be within the range of 45°.

Incidentally, when releasing the workpiece 8, the cam 10 may be rotated in the direction of arrow B in FIG.

In the present invention, the workpiece 8 to be gripped is not limited to a cylindrical shape. For example, even if the cam has a rectangular cylindrical shape, the shape of the cam and the amount of displacement of the gripping claws may be set accordingly. Further, when the gripping claws are installed inside the cam, the outer surface of the workpiece can be gripped, contrary to the above embodiment.

〔Effect of the invention〕

As described above, the present invention grips and releases a workpiece by widening and contracting the width of a plurality of gripping claws by rotating a cam, so it is possible to obtain a strong gripping force with a simple structure. Accordingly, it is possible to provide a hand device for an industrial robot that can be made small in size and inexpensive.

[Brief explanation of drawings]

FIG. 1 is an overall side view of an industrial robot according to the present invention, FIG. 2 is an enlarged sectional view of the part shown in FIG. 1, and FIG.
The figure is a sectional view taken along the - line in Figure 2, showing the state before gripping the workpiece, Figure 4 is an operation diagram showing the state in which the workpiece is gripped, Figure 5 is an enlarged view of section V in Figure 3, FIG. 6 is a diagram showing the principle of expanding the rotational force of the cam to the gripping force of the gripping claws. 9: Main body, 10: Cam, 11: Drive device, 1
2: rotating shaft, 13: gripping claw, 14: shaft, 15: gripping part, 16: roller, 17: shaft. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A main body fixed to the tip of a robot arm; a rotating cam that is rotated by a drive device housed in the main body and has a plurality of inclined surfaces on its contour; and a rotating surface of the rotating cam. a plurality of gripping claws arranged inside the body, one end of which is pivotally connected to the main body by a shaft, and one end of which has a gripping portion for a workpiece on one side of the other end; and an eccentric screw fixed to the other side of the other end of the gripping claws with a screw. a shaft having a hole; a shaft rotatably fitted to the shaft having the eccentric screw hole, disposed in contact with the slope of the rotary cam, and pressed against the slope in response to rotation of the rotary cam;
a roller that causes the gripping claw to radially expand and contract in a rotating plane of the rotary cam around the shaft on the one end side; and a holder that holds the roller in constant contact with the slope of the rotary cam. A hand device for an industrial robot, characterized by comprising a means and the following.