Clamping mechanism suitable for tensile strength test of universal testing machine

Abstract

The invention discloses a clamping mechanism suitable for a tensile strength test of a universal testing machine. The clamping mechanism comprises a clamping body; an opening of the clamping body is internally provided with a wedge-shaped clamp plate; one side, away from the clamping body, of the wedge-shaped clamp plate is provided with an inner concave part; the inner concave part is internally provided with a wedge-shaped bayonet, a wedge-shaped included angle alpha of the wedge-shaped bayonet is less than a wedge-shaped included angle beta of the wedge-shaped clamp plate, and ejector rods are arranged on the wedge-shaped clamp plate; the wedge-shaped bayonet is provided with an outer convex part; the outer convex part is in halved joint with the inner concave part of the wedge-shaped clamp plate, both ends of the inner concave part of the wedge-shaped clamp plate are each provided with a mounting groove, both ends of the outer convex part of the wedge-shaped bayonet are respectively provided with through holes which are coaxial but have different diameters, and the through holes are respectively provided with a guide rod and a spring; the guide rod is inserted into the mounting grooves of the inner concave part of the wedge-shaped clamp plate, and the wedge-shaped bayonet can slide along the guide rod. The wedge-shaped clamp plate has relatively large expansion volume and wider application scope, and a test piece is easier to clamp and disassemble; when the test piece is clamped tightly, the expansion quantity of the bayonet is small, and the self locking property is strong, so the test piece is easy to clamp and lock tightly.

Description

technical field [0001] The invention relates to a clamping mechanism, in particular to a clamping mechanism suitable for the tensile strength test of a universal testing machine. Background technique [0002] Universal testing machine, a material testing machine integrating tensile, bending, compression, shearing, ring stiffness and other functions, is mainly used for mechanical performance tests of metal and non-metal materials. Ideal testing equipment for departments such as quality supervision stations. Universal testing machine is also called universal material testing machine, or tensile machine, double screw series, integrated structure of control, measurement and operation, integrating contemporary advanced technology, with high precision, wide speed range, compact structure, convenient operation, Stable performance and other advantages. It is suitable for tensile, compression, bending and creep tests of material samples and products such as plastics, waterproof mat...

AI Technical Summary

Problems solved by technology

[0005] In the existing universal testing machine, the collets used are generally wedge-shaped collets. During the process of stretching the test piece, the wedge-shaped collets always clamp and loosen along a wedge-shaped angle. If the value is large, the expansion of the bayonet is large, and the specimen is easy to install and disassemble, but the self-locking performance is poor. To clamp the specimen, the teeth of the bayonet should pay a large cutting force, so that the bayonet is prone to slipping or Tooth collapse, and the durability of the bayonet is reduced. If the wedge angle is smaller, although the expansion of the bayonet is small, the chuck has strong self-locking performance, and it is easy to clamp and lock the test piece, especially the colored Metal specimens and low-hardness specimens are clamped and locked firmly, however, the tighter the clamping and the firmer the lock, the more difficult it is to disassemble the specimen remains

In view of this, some testing machines use hydraulic wedge chucks, which not only fail to solve the problem fundamentally, but often appear new contradictions that the hydraulic cylinder is easy to leak or leak oil, which affects the test

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