CN87206841U

CN87206841U - Friction type clamp for pure tensile test of concrete

Info

Publication number: CN87206841U
Application number: CN 87206841
Authority: CN
Inventors: 杨久俊
Original assignee: MILITARY ENGINEERING INST
Current assignee: MILITARY ENGINEERING INST
Priority date: 1987-04-20
Filing date: 1987-04-20
Publication date: 1988-06-08

Abstract

The utility model provides a friction type clamp for pure tensile test of concrete, comprising a draw rod, a rod, a shaft, screw caps, clamping chucks, a rubber packing, guide springs, a self locking and springs. External force is transferred to a test specimen through the clamping chuck from only one fixed pivot, which makes the test specimen have no torque, no eccentric moment and no two direction stress to acquire the true pulling and pressing intensity of the test specimen.

Description

Friction type clamp for pure tensile test of concrete

The utility model relates to a kind of friction-type concrete pure extension test fixture.

More present concrete stretching test methods commonly used, common shortcoming is to obtain two intensity of tension and compression in same test specimen, and often has moment of torsion and eccentricity to exist in the drawing process.Johnston and Steve Sidwell have designed a kind of stretching clamp (original text carries M, C, R, VoL20, No.65,12/1968) of frictionally effect, and bigger improvement has been arranged.This anchor clamps external force is passed to test specimen by increased pressure board by a fixed pivot and a sliding fulcrum, has eliminated moment of torsion and eccentricity in drawing process basically, can obtain two intensity of tension and compression.But shortcoming is to be two to stressed section in the clamping plate, and test specimen is easily broken in the exit, and two are unable to estimate to stress; Clamping plate contact with the test specimen rigidity, easily produce stress and concentrate.Owing to there is above-mentioned shortcoming, two intensity authenticities of the tension and compression that test specimen obtains are relatively poor.

The purpose of this utility model is to propose a kind of friction-type concrete pure extension test fixture, makes test specimen not have moment of torsion in process of the test, not have two to stress in square and the clamping plate without acceptance of persons, thereby obtains real tension and compression two intensity of concrete sample.

Friction-type concrete pure extension test fixture is made up of pull bar, chain bar, axostylus axostyle, nut, chuck, rubber liner, retainer spring, self-locking spring.The effect that retainer spring is set is to make pull bar not depart from the axostylus axostyle center.The length of chuck is no more than chain bar infall, makes external force only be passed to test specimen by clamping plate by a fixed pivot, eliminates two basically to stress.Chuck midsole layer rubber liner, chuck are contacted by original rigidity with test specimen and become gentle contact, make the even distribution of stress not produce concentrated.

Friction-type concrete pure extension test fixture described in the utility model makes and no moment of torsion in the test specimen, square and do not have two to stress is without acceptance of persons truly drawn, presses two intensity.

The utility model has following accompanying drawing:

Fig. 1 is these anchor clamps YZ plane.

Fig. 2 is these anchor clamps YX plane

With reference to Fig. 1, Fig. 2: (1) is pull bar; (2) be the chain bar; (3) be axostylus axostyle; (4) be nut; (5) be chuck; (6) be rubber liner; (7) be retainer spring; (8) be self-locking spring.The material of remaining part is all used metal except that rubber liner.

The effect of pull bar (1) is that these anchor clamps and universal testing machine are joined.Chain bar (2) plays skeleton function in these anchor clamps.The effect of axostylus axostyle (3) is connection chain bar and chain bar, chain bar and chuck, chain bar and pull bar.The axostylus axostyle of the chain bar infall of chuck top, the position that can limit test specimen makes external force only be passed to test specimen by clamping plate by a fixed pivot, thereby has eliminated two to stress.The effect of nut (4) is a fixed axostyle.The effect of chuck (5) is to make anchor clamps can clamp test specimen.The effect of rubber liner (6) is, makes that chuck and test specimen are flexible to contact, and stress can evenly distribute, and does not produce concentrated.The effect of retainer spring (7) is, makes the position of axostylus axostyle placed in the middle, is not offset.The effect of self-locking spring (8) is, makes the surface of contact of chuck and test specimen can keeping parallelism, stressed evenly.

Claims

1, a kind of friction-type concrete pure extension test fixture of forming by pull bar, chain bar, axostylus axostyle, chuck, the chain bar infall that it is characterized in that the chuck top of these anchor clamps has axostylus axostyle, make the length of chuck and test specimen be no more than chain bar infall, external force passes to test specimen by chuck only by a fixing intersection point.

2, according to the friction-type concrete pure extension test fixture of claim 1, it is characterized in that there is rubber liner the chuck inboard of these anchor clamps.

3, according to the friction-type concrete pure extension test fixture of claim 1 to 2, it is characterized in that these anchor clamps have self-locking spring.