JPH0355885Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to a tightening handle used for tightening the grip teeth of a material testing grip.

(Conventional technology) By having a pair of left and right gripping teeth and rotating a tightening shaft connected to these with a handle,
There are grips for material testing that tighten and secure the test piece from both sides. Conventional handles used to tighten the grip teeth of this type of grip were designed so that the external force applied to them was directly transmitted to the tightening shaft, so it was necessary to keep the rotational torque transmitted to the tightening shaft within a certain range. I couldn't do it.

By the way, in the tensile test of soft materials, it is known that the clamping pressure of the test piece with the grip has a large influence on the test results. for example,
If the clamping pressure is too high, the chucking part of the test piece will become weak, causing early breakage in this part, resulting in abnormally low measured values. Furthermore, if the clamping pressure is too low, slippage will occur between the gripping teeth and the test piece, resulting in inaccurate measurements.

(Problems to be solved by the invention) By the way, the conventional tightening handle described above relies on the experience and intuition of the operator to adjust the tightening strength of the test piece, so the tightening pressure is not necessarily constant.
There was a problem that accurate measurement values could not be obtained.

(Means for Solving the Problems) In order to solve the above problems, the present invention has the following configuration. That is, the tightening handle according to the present invention includes a mounting portion that is attached to a rotated object such as a test specimen tightening screw, and a handle member to which an external force is applied to rotate the rotated object through the mounting portion. The present invention is characterized in that a ratchet mechanism is interposed between the handle member and the attachment portion, which does not transmit external force when the rotational torque exceeds a predetermined value.

(Function) If the rotational torque is less than a predetermined value, the rotational force applied to the handle member is transmitted to the mounting part,
Rotate the object to be rotated. When the rotational torque exceeds a predetermined value, the ratchet mechanism operates and no longer transmits external force to the mounting portion.

(Embodiment) FIGS. 1a and 1b are front and side views showing one embodiment of the present invention, and FIG. 2 is a sectional view of the main part thereof. This tightening handle 1 has a square core. A mounting portion 4 having a fitting hole 3 is provided, and a ratchet member 5 is fitted onto the outer periphery of the mounting portion 4. A plurality of handle members 7, . . . are provided protruding from the outer peripheral surface of the ratchet member 5.

A ratchet mechanism 9 is interposed between the mounting portion 4 and the ratchet member 5. Ratchet mechanism 9
A sphere 12 that engages with a sphere engagement recess 11 formed on the outer circumferential surface of the mounting portion 4, and a ratchet member 5.
an adjustment screw 15 that is screwed into a threaded portion 14a of a diametrical ratchet hole 14 provided in
It consists of 7. The rear part of the adjusting screw 15 is a shaft part 15a having a tightening tool insertion hole 18 on the rear end surface. Scales 19 are provided at predetermined intervals on the outer surface of the shaft portion 15a.

Next, how to use this tightening handle 1 will be explained. FIG. 3 shows a state in which a general material testing grip is being tightened. This grip 21 is connected to a connecting rod 2 that is attached to the material testing machine at the center of the upper part of a roughly horseshoe-shaped frame 22.
3 is screwed on and the legs 22 are divided into two parts.
A cylindrical grip tooth support portion 25, 25' having a horizontal axis is integrally formed at the lower end of the grip teeth a, 22a'. The shaft holes provided in the grip tooth supports 25, 25' have a smooth guide hole 26 at the front (test side) and a screw hole 27 at the rear.
It's getting old. A grip tooth holder 30, which is prevented from rotating by a key 29, is slidably fitted into the guide hole 26. The holder 30 has a mounting hole 32 in the axial direction and a pin hole 33 perpendicular to the shaft mounting hole 32, and a fixing pin 35 that inserts the leg portion 34a of the grip tooth 34 inserted into the mounting hole 32 into the pin hole 33. By fixing the grip tooth 34 to the other grip tooth 34', the grip tooth 34 is held opposite to the other grip tooth 34'. A tightening screw 39 is screwed into the screw hole 27 and has a disc-shaped engaging portion 37 projecting from its front end and a square bar-shaped handle fitting portion 38 projecting from its rear end. The engaging portion 37 engages with the rear end of the holding body 30, and as the tightening screw 39 moves forward and backward, the holding body 30 holding the gripping teeth 34 moves back and forth along the guide hole 26.

When tightening the test piece, the fitting hole 3 of the tightening handle 1 is fitted into the handle fitting part 38 of the grip 21, and a rotational force is applied to the handle member 7. The rotational force applied to the handle member 7 is transmitted from the ratchet member 5 to the mounting portion 4 via the sphere 12, and rotates the tightening screw 39 of the grip 21 in a predetermined direction. The tightening screw 39 moves forward in the screw hole 27 by rotation, presses the holder 30 forward, and presses the grip teeth 14 against the test piece. However, when the rotational torque for rotating the tightening screw 39 becomes higher than a predetermined value, the sphere 12 resists the compression spring 17 and moves into the engagement recess 1.
1, the ratchet member 5 idles around the mounting portion 4. That is, when the clamping force of the grip teeth 14 reaches a predetermined value, no matter how much the handle 1 is turned, the clamping force will not be tightened any further. The set value of this tightening force can be adjusted by moving the adjustment screw 15 forward or backward to change the compression force of the compression spring 17. In the illustrated example, since 19 scales are provided on the shaft portion 15a of the adjusting screw 15, the tightening depth of the adjusting screw is clearly displayed, making it easy to adjust and to maintain a predetermined tightening force. It can be reproduced any number of times.

(Effects) As is clear from the above explanation, in the tightening handle according to the present invention, external force is transmitted to the mounting part via the ratchet mechanism, so when the rotational torque exceeds a predetermined value, the rotational force is transferred to the mounting part. will no longer be transmitted to. Therefore, when this handle is used as a handle for tightening the grip teeth of a material testing grip, etc., the tightening force can be controlled within a certain value, and accurate test results can be obtained.

[Brief explanation of drawings]

FIG. 1a is a front view of one embodiment of the tightening handle according to the present invention, FIG. 1b is a side view thereof, FIG.
The figure is an explanatory diagram showing the usage state. 1...Tightening handle, 4...Mounting part, 5
... Ratchet member, 9... Ratchet mechanism, 1
DESCRIPTION OF SYMBOLS 1... Engagement recessed part, 12... Ball, 15... Adjustment screw, 17... Compression spring.

Claims (1)

[Scope of utility model registration request] A mounting section that is attached to a rotated object such as a test piece tightening screw, and a handle member to which an external force is applied to rotate the rotated object via the attachment section, and a space between the handle member and the attachment section. The tightening handle is equipped with a ratchet mechanism that does not transmit external force when the rotational torque exceeds a predetermined value.