JPH04303733A - Gripper for material testing machine - Google Patents

Abstract

PURPOSE:To hold a test piece accurately and to achieve the compact size and the light weight of a gripper itself when the test piece is automatically held. CONSTITUTION:In a gripper for material testing machine, a nut 16 which is screwed with a main body 2 of the gripper at a supporting shaft 12 that is attached to the main body of a testing machine is provided. The nut 16 is rotated, and the main body 2 of the gripper is moved up and down. Thus, a pair of gripping teeth 10 provided in the main body 2 of the gripper are opened and closed. A slant surface which is inclined with respect to a horizontal plane is formed at the outer surface part of the nut 16. A plurality of actuators for pushing the slant surface in the up and down directions are provided along the outer surface of the nut at a specified interval.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a test piece gripping tool which is attached to a material testing machine.

0002

2. Description of the Related Art A gripping tool is used which includes a pair of left and right gripping teeth and grips a test specimen by a wedge effect between the gripping teeth and the gripping body supporting the gripping teeth. As shown in FIG. 2, this type of grip has a grip main body 25 with a wedge-like surface formed on the inside, and a pair of left and right wedge-shaped grip teeth 26 and 27 that grip the test piece from both sides. , the rear end of the grip teeth is supported by a support shaft 28 attached to the testing machine main body, and a cap nut 30 screwed onto a threaded rod portion 29 provided at the rear end of the grip main body is rotated. By moving the main body 25 up and down along the support shaft 28, a clamping force is applied to the gripping teeth 26 and 27. The rotation of the cap nut is done using the handle 3 attached to the cap nut.
2, or by transmitting power from a motor 33 to a gear attached to a cap nut.

0003

Problems to be Solved by the Invention The above-mentioned conventional grips of the type in which the grip teeth are manually opened and closed have a problem in that labor-saving and automation cannot be achieved. In addition, in the type that uses a motor to open and close the grip teeth, the motor is installed at a position away from the center of the grip, that is, the center of the cap nut, which creates an eccentric load on the grip and makes the grip more accurate. In addition to the problem of not being able to grip the test piece, there was also the problem of increasing the size of the grip itself.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a grip for a material testing machine that can automatically grip a test piece and that can be made smaller and lighter.

[0005]

[Means for Solving the Problems] In order to solve the above problems, the present invention employs the following configuration. That is, the grip for a material testing machine according to the present invention is provided with a nut that is threadedly engaged with the grip main body on a support shaft attached to the test machine main body, and by rotating the nut to move the grip main body up and down, A grip for a material testing machine that opens and closes a pair of grip teeth provided in the grip main body,
The nut is characterized in that a slanted surface is formed on the outer periphery of the nut at intervals with respect to a horizontal plane, and a plurality of actuators for pressing the slanted surface in the vertical direction are provided at predetermined intervals along the outer periphery of the nut.

[0006]

[Operation] The nut is rotated by sequentially pressing the inclined surface of the inclined plate attached to the cap nut around the circumference using a plurality of cylinder actuators. Since the plurality of actuators are arranged around the center of the grip, no large eccentric force is generated on the grip.

[0007]

[Embodiment] FIGS. 1 and 2 are schematic diagrams showing the structure of an embodiment of the present invention. This grip 1 for a material testing machine includes a grip main body 2 having a U-shaped recess 3 when viewed from the front. A pair of left and right wedge action surfaces 4, 4 are provided on both sides of the recessed portion 3 and are formed as inclined surfaces such that the distance between the front ends thereof gradually narrows. A threaded rod portion 5 with a thread cut on the outer periphery is provided protruding from the rear end portion of the grip main body 2. and,
A through hole 6 is bored through the rear part of the grip main body 2 and the threaded rod part 5 in the axial direction and exits from the rear end into the recess 3. One side surface of the recess 3 is formed as a tapered wedge action surface 7 having the same angle as the wedge action surface 4, and the opposite surface has left and right flanks on which tooth surfaces 9 with minute irregularities are formed. A pair of gripping teeth 10, 10 are held. Grasping teeth 10,
The rear end portion of the gripper 10 is attached to a support shaft 12 for attaching the tester main body, which is inserted into the through hole 6 of the grip main body. An intermediate flange 13 is provided on the rear side of the support shaft 12. The threaded rod portion 5 of the grip main body 2 has a threaded hole 15.
A cap nut 16 having a diameter is inserted through the support shaft 12 and is screwed into the intermediate flange 13 in an engaged state. Note that the grip main body 2 is slidably fitted onto the support shaft 12, and its rotation is restrained by a key 19.

A disc 17 is attached to the outer periphery of the cap nut 16 in an inclined manner. As shown in the figure, on the disk 17, there is a cylinder actuator 20 that comes into contact with the inclined surface of the disk and presses it downward.
6, a plurality of them are arranged concentrically and coaxially at equal intervals. The cylinder actuator 20 is an air cylinder fixed to the support shaft 12 and attached to the lower case 18, and is driven to sequentially press the disc 17 by a drive control device (not shown).

The cylinder actuator 20 moves the disk 1
By sequentially pressing the inclined surfaces 7 around the circumference, the cap nut 16 is rotated. When the cap nut 16 is rotated, the grip main body 2 screwed onto the cap nut 16 moves up and down along the support shaft. When the cap nut 16 is rotated in the direction of raising the grip main body 2, the gap between the flanks of the grip teeth 10 held in the recess 3 becomes narrower due to the wedge effect, thereby pinching the test piece. The cylinder actuators 20 are arranged evenly around the center of the cap nut and the grip, so when pressing the disc, no large eccentric force is generated on the grip, allowing accurate gripping of the specimen. can be done. Furthermore, since the drive source for rotating the cap nut is arranged around the grip, the structure of the grip itself is compact.

In the above embodiment, an inclined disk is attached to the cap nut, and the actuator presses the inclined surface of the disk to rotate the cap nut. The surface may be pressed. Further, as the actuator, in addition to an air cylinder, a hydraulic type, an electric type, or the like may be used.

[0011]

[Effects of the Invention] As is clear from the above description, according to the grip for a material testing machine according to the present invention, no large eccentric force is generated in the grip when gripping a test piece, so that the test can be carried out accurately. You can now grasp pieces. Furthermore, when attempting to automate the gripping of a test piece, it has become possible to reduce the size and weight of the grip itself.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the invention.

FIG. 2 is a plan view of main parts of the embodiment.

FIG. 3 is a schematic diagram showing a conventional example.

[Explanation of symbols]

2 Grip body 3 Recessed part 4 Wedge action surface 10 Grasping teeth 12 Support shaft 16 Cap nut 17 Inclined disc 20 Actuator

Claims (1)

[Claims] Claim 1: A support shaft attached to the testing machine body is provided with a nut that is screwed into the grip body, and by rotating the nut and moving the grip body up and down, In the grip for a material testing machine which opens and closes the grip teeth of the nut, an inclined surface is formed on the outer periphery of the nut and is inclined with respect to a horizontal surface, and
A grip for a material testing machine, characterized in that a plurality of actuators that press the inclined surface in the vertical direction are provided at predetermined intervals along the outer periphery of the nut.