GB450028A - An improved machine for testing of materials - Google Patents

Abstract

450,028. Testing physical qualities of materials. WILLIAMS, G., Russell House, Stennels Avenue, Quinton, Birmingham. March 12, 1935, No. 7628. [Class 106 (ii)] A gapped ring of the material is pulled apart by a force applied across a diameter of the ring, a diagram being automatically recorded, the ordinates representing force applied and extension of the ring respectively. A plate 4 fixed to a standard 3 is provided with three spaced knife edges 5 one above the other. Within the hollow standard 3 is arranged a shaft 6 driven by bevel gear 8, 9 from a hand wheel 11 and driving at the other end gearing 14, 15 of which the latter is formed as a nut which on turning slides a screwed shaft 17 fixed to a frame 18 guided on the standard 3. Rotating in ball bearings 19 in the frame 18 is a horizontal shaft 20 to which is keyed a bracket carrying a depending arm 21 forming a swinging weight system and provided with a small adjustably clamped mass 22. The bracket carries two spaced hooks 24 each forming an anchorage for one end of a flexible steel strap 25 passing over a cylindrical or part cylindrical surface in the bracket or on the shaft 20 and coaxial therewith. The other end of each strap is anchored to a horizontal bar 26 rigidly connected by parallel rods 27 with a cross-bar 28 carrying a knife-edged projection 29 in line with the knife edge 5. The bars 26, 28 have also stretched between them piano wires 31 which are passed around and positively keyed to a cylindrical boss 32 on the shaft of a drum 35 adapted to receive a second chart. Mounted on the bracket opposite the arm 21 is a ball-bearing roller 36 engaging between the parallel edges of two light bars 37 depending from a bar 38 adapted to slide on two spaced wheels 39. One end of a rod 41 connecting the arms 37 for slight adjustment purposes, is provided with a pen 42. A scale 43 on bar 38 co-operates with a hair-line on a cursor or pointer 44 carried by a screwed rod 45. An arcuate metal strip 46 attached to the arm 21 is toothed to co-operate with a fixed pawl 47 to hold arm 21 in the position reached when the ring breaks. In use, the ring is placed over the knife edge 29 and one of the knife edges 5 and the wheel 11 turned. The pull of the frame 18 acting through the straps causes the arm 21 to swing out of the vertical. The piano wires turn the drum proportionally to the extension of the specimen and the roller 36 and arms 37 and 38 are moved horizontally proportionally to the displacement of the swinging weight or lead. The Provisional Specification describes also a modification in which the load is applied by a spring balance arrangement, the springs being stretched by a screw and nut device operated by a hand wheel. In this case, the chart-carrying drum is slidable on a vertical spindle proportionally to the extension of the springs and is rotated by wires in accordance with the movement of the movable knife-edge.