JPH0536199Y2 - - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a grip connection mechanism used in a material testing machine that performs a tensile test on a specimen under a low load.

B. Conventional technology Figure 3 shows the conventional low load (e.g. tensile force)
(100g or less) This shows a material testing machine for tensile testing.

A locking tool 55 having a hook-shaped locking part 54 is screwed onto the tip of the sensing lever 53 of the load cell 52 fixed to the crosshead 51, and a universal joint 56 having hook-shaped ends is suspended therefrom. be done. An upper grip 58 is suspended from the universal joint 56 via a locking portion 57. The lower grip 59 is fixed to a fixture 61 installed on the table 60, and the upper grip 58 and the lower grip 59 are used to hold, for example, a filament specimen TP.
is installed.

During the tensile test, the crosshead 51 is moved to pull the specimen TP via the universal joint 56 and the upper grip 58, and the sensing lever 53 is distorted by the tensile force to detect the load. do.

C Problems to be solved by the invention However, in the above-mentioned connection mechanism, the locking portions at both ends of the universal joint 56 and the locking portion 5
4 and 57, the locking point may deviate from the load axis LC by the dimension a, or the upper grip 58 may be tilted and not suspended along the load axis LC, as shown in FIG. As a result, the resting position of the upper grip 58 becomes unstable, and the force along the load axis cannot be stably transmitted to the load cell 52, making it difficult to achieve high accuracy, especially in material tests with low loads (pulling force of 100 g or less). Measurement was not possible.

An object of the present invention is to provide a grip connection mechanism for a material testing machine that solves these problems.

D. Means for Solving the Problem A coupling device in which a locking portion that slopes downward toward the locking point with the upper grip is formed on one end side and a conical pivot portion is formed on the other end side; A pivot receiver is attached to the intersection of the tip of the sensing lever with the load shaft and pivotally supports the pivot part with a recess formed at the top.

E Action The pivot part of the coupling tool is supported by the pivot receiver to suspend the coupling tool from the load cell. The coupling is oriented in the direction of the load axis, and the upper grip connected to it slides on the downward slope of the locking part of the coupling due to its own weight and swinging around the pivot part of the coupling, and the upper grip is connected to the load. Suspended at a locking point on the shaft.

F. Example An example of the present invention will be described with reference to FIGS. 1 and 2. Note that parts similar to those in FIG. 3 will be described with the same reference numerals.

In FIG. 1, the sensing lever 53 of the load cell 52 extends in a direction perpendicular to the load axis. A connecting tool 100 that connects the sensing lever 53 and the upper grip 58 includes a pivot 1 formed with a conical pivot portion 2 on the sensing lever side, and a hook-shaped engagement formed on the upper grip side. It consists of a stop part 3 and a joint frame 4 that connects the pivot 1 and the stop part 3. The locking portion 3 is screwed onto a bolt 7 that is fixed to the joint frame 4 with a nut 5 and a lock nut 6. The apex 2a (FIG. 2) of the pivot portion 2, the axis of the bolt 7, and the locking point 3a of the locking portion 3 are arranged in a straight line so as to coincide with the axis of the connector 100.

As shown in FIG. 2, a V-groove 12a of depth d ₁ is formed in the upper end of the pivot receiver 12 fixed to the tip of the sensing lever 53 with the nut 11, with which the apex 2a of the pivot portion 2 makes point contact. , the pivot portion 2 is pivotally supported in this V-groove 12a.

To attach the connector 100 to the load cell 52, connect the threaded end of the bolt 7 and the pivot receiver 12.
and the head 12b, _d2 is set to be greater than _d1 , and the pivot portion 2 is inserted and locked into the V-groove 12a. Tighten the bolt 7 and set the distance between it and the pivot receiver 12 so that d ₂ <d ₁ . This prevents the connector 100 from falling off.

Next, the locking portion 57 of the upper grip 58 is locked to the locking portion 3 . The connector 100 has a pivot portion 2
A pivot bearing-like universal joint mechanism consisting of a V-groove 12a and a V-groove 12a pivotally supports the pivot receiver 12 in a state where it can freely swing. Therefore, even if the locking portion 57 of the upper grip 58 is locked at a position shifted from the locking point 3a of the locking portion 3, the locking point 3a will be moved due to its own weight and the swinging of the connecting tool 100.
It slides until it stops. Further, as shown in FIG. 2, since the apex 2a of the pivot portion 2 makes point contact with the V-groove 12a, the contact resistance is extremely small and the coupling tool 10
0 is oriented in the perpendicular direction due to its own weight and its axis coincides with the load axis, so the upper grip 58 is suspended directly below the locking part 3.

As a result of the above, the load (for example, a low load of 100 g or less) applied to the specimen TP is
a, the load is transmitted to the sensing lever 53 via the V-groove 12a, and the load is accurately measured by the load cell 52, making it possible to perform measurements with reproducibility.

G. Effect of the invention According to the invention, the upper grip slides on the downward slope of the locking part of the connector due to its own weight and the swinging movement about the pivot part of the connector, and the load axis Since it is suspended from the upper locking point, load detection by the load cell is highly accurate and reproducible, and stable measurements are performed especially in low-load tests.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing an embodiment of the present invention, Fig. 2 is an enlarged sectional view showing the engaged state of the main parts of the embodiment, and Fig. 3 is a front view showing the overall structure of a conventional material testing machine. 4 are enlarged views showing the engaged state of the universal joint portion in the prior art. 1... Pivot, 2... Pivot part, 2a...
Vertex, 3... Locking part, 4... Joint frame, 7...
...Bolt, 12...Pivot receiver, 12a...
V groove, 52...load cell, 53...sensing lever, 57...locking portion, 58...upper grip.

Claims (1)

[Scope of Claim for Utility Model Registration] A sensing lever is provided protruding from a load cell installed on the crosshead side in a direction perpendicular to the load axis, and an upper grip is suspended at the intersection of the tip of this sensing lever with the load axis. In a grip connection mechanism for a material testing machine, a connection in which a locking part is formed at one end with a downward slope toward the locking point with the upper grip, and a conical pivot part is formed at the other end. and a pivot receiver that is attached to the intersection of the tip of the sensing lever and pivotally supports the pivot part with a recess formed at the top.