GB415104A - A mechanical testing machine - Google Patents

Abstract

415,104. Testing physical qualities of materials. GALE, R. C., 10, Gourock Road, Eltham, London. Feb. 17, 1933, No. 4951. [Class 106 (ii).] The specimen is held between two relatively movable members, so that movement of one of them is transmitted to the other through the test piece against the influences of a compression spring surrounding the second member and located in a cylinder having a piston to which the member is secured. An I-section beam 11 is bolted to a base and on the top of the beam are bolted four members 12, 13, 14, 15 to enclose two cubical spaces. An inverted channel section beam is bolted to the top of the members to complete a stiff framework. A draw bar 20 of square section slides through the member 14 and a reduced portion 21 of circular cross-section slides through the part 15 into a cylinder 26. A spring 22 surrounds the part 21 abutting against a washer 23 at one end and a washer 24 backed by a cup leather 25 at the other end. The right hand end of the bar 20 is formed with a socket to receive a shackle 28 which is secured by a taper pin 29. A similar bar 30 has a cylindrical portion 31 on which is a threaded sleeve 32 engaging a nut 35 secured to the member 12. A hub 36 fitted with spokes 37 is keyed to the sleeve and engages a thrust bearing 33 secured by nuts 34. A spring strut 44 engages at one end a part 38 carried by the draw bar 20 and at the other the member 14. It also has a fork engaging a pivoted quadrant member actuating the needle of a dial gauge 18. The needle of this instrument engages a friction held maximum pointer which reads the maximum compression of the spring and hence the load. The bar 30 carries a dial gauge 57 the plunger of which engages an abutment 59 on a rod 54 secured to the member 20. The reading of this gauge gives the extension of the specimen. The grip for the specimen as shown in Fig. 3 and comprises a socket 63 having a squared end 64 and a bore to receive the specimen which is clamped between hardened grips 65 one of which is on the end of a plug 66 screwed into the socket. The specimen is clamped while the ends 64 of the grips are assembled in a jig 68 and is then slipped into the keyhole ends 60 of the shackles 28, a plate 61 underneath preventing them falling out. For compression and hardness tests shackles shown in Figs. 4, 5 are used. The shackle 73 is secured to a lozenge-shaped plate 72 attached to rods 71 carrying a lozengeshaped plate 70 in which is supported a part 74 which for hardness tests carries a ball 75 but for compression tests is flat. The other shackle is attached to a plate 72a from which rods 71a support a plate 70a between which and the part 74 the specimen is compressed. For a bending test, the specimen is held between a knife edge 85 on one bifurcated shackle 84, and two pins 81 on another similar shackle 80.