GB488800A - Improved machine for testing the physical qualities of metals - Google Patents

Abstract

488,800. Testing physical qualities of materials. EUGENE, F. Jan. 20, 1937, No. 1680. Convention date, Jan. 30, 1936. [Class 106 (ii)] A machine for making bending, shearing, compression, tensile and hardness tests comprises means for securing a test piece, a load applying device, calibrated resilient bars capable of co-operating with said securing means the movement of which against the resistance of the bars is transmitted to a movable mirror, a second movable mirror to which the distortion of the test piece is transmitted, a reading screen and means for projecting a light ray on to the screen after reflection at least from the first mirror, and means for clearing the path of the ray so as to be reflected also in a second mirror. The load applying means is constituted by a vertical shaft adapted to slide without turning in the head of a frame 1. The shaft is screwed to engage a nut mounted in ball bearings and turned by pulley and worm gear from a motor carried by the frame 1, and is prevented from turning by a key which may be withdrawn to allow of rapid movement of the shaft. A table 23 the stem of which slides in ball bearings engages by a stud 24 one of three resilient bars 30, which are arranged in a unit 31 which may be slid by levers 34, 35 to bring any bar underneath the stud 24, the bars having blocks 37 to give them the same height at the centre. The bar 30 engages a stud 43 on the short arm 44 of a lever pivoted at 45, the long arm 41 of which has attached to it a metal tape 42 the other end of which is attached to a pulley 52 on a spindle 49 carrying a mirror 40. The table carries a bracket 66 and yoke 67 for supporting the specimen a as shown. A lug 70 on the yoke is adapted to engage one arm 71 of a bell-crank lever, the other arm of which engages a pivoted mirror 73, which is tilted an amount proportional to the distortion of the specimen. Light from a source 81. passes through a hole 4 to mirror 73 and is reflected to mirror 40 and from there to another mirror and then to the reading screen. For shearing, compression and hardness tests, the light is reflected via mirrors 85, 89, 90 to 40 and then follow the same path as before. These paths are of equal length to avoid having to focus the reticules every time a change is made in the nature of the test.