GB1254128A - Testing materials under transient mechanical stress - Google Patents

Abstract

1,254,128. Tensile testing apparatus. CENTRE NATIONAL DE RECHERCHES METALLURGIQUES. Oct. 24, 1969 [Oct. 24, 1968], No. 52292/69. Heading G1S. A tensile test specimen held between a movable cross-bar 27, Fig. 2 and a relatively fixed stirrup 57 may be tensioned by rotating a coupling disc 10 by an electric motor 2 and flywheel 3 driving a mating coupling disc 9, Fig. 1. The coupling 10 rotates a cam 7 mounted in bearings 12, 13 and having a protuberance 14, Fig. 5c, the cam normally bearing on a roller 15, Fig. 5b, in the centre of a stirrup 16 pressed by a spring against the cam and sliding on four fixed guide rods such as 17 and 18. The sliding movement of the stirrup 16 by the cam is transferred by fixed tie rods 28, 29 to a cross-bar 27 slidable on fixed guide rods 42, 43 screw threaded through a stirrup 57 which may be driven along the screw threads by means of a motor 58 and a chain drive 60. The specimen to be tensile tested is a rod 71, Fig. 9, which is threaded into sleeves 74, 75 abutting against a fixed shoulder 77 of the stirrup 57 and against a shoulder on the bar 27 which is moved away from the stirrup 57 by translation of the stirrup 16 and rods 28, 29. The cam carries a lug 99, Figs. 5c, 5d, which when the cam rotates abuts against a stem 98 on an arm 88 so that the arm is drawn downwardly and pivots down a roller 83 carrying the cylinder 15. The stem 98 is moved into the path of the lug 99 by operation of a solenoid and the cylinder 15 is contacted and pushed back by the protuberance 14 on the cam 7. When the protuberance 14 has passed the roller 83 and cylinder 15 they are freed and returned with the arm 88 by a spring 91 and the stem 98 is retracted to avoid a further test extension movement. The specimen may be rapidly heated or gas or water cooled by apparatus placed between the rods 42, 43 and the speed of the cam 7 may also be varied to alter the time of deformation. The position of the test specimen may be altered with respect to the cross-bar 27, Fig. 10 (not shown) by rotating a toothed bush (108) screw threaded to one end of the specimen.