GB645331A - Improvements in strain gauges and methods of and means for the production thereof - Google Patents

Abstract

645,331. Compression and tension resistances. GALL. D. C. June 19, 1944, No. 11668. [Class 37] [Also in Group XXII] A resistance strain gauge comprising a length of wire formed into a grid of parallel runs is produced from a length of wire 1, held at a constant tension by a spring-urged hook 16 by drawing the wire out into loops between stationary hooks 25 by hooks 34 which are moved back one at a time to form the grid 1a to 1f (see Fig. 9). At this stage an internally-heated platform 38 is raised to bring a base 2 into contact with grid and cement is applied and allowed to set and so to secure the grid to the base. Hooks 25, 34 are raised free from the wire which is cut near the outside edges of hooks 18, 19 to leave the grid ready for attachment, of the terminal strips (not shown) which are further secured by cement to the base 2. The base 2 may be a continuous strip (see Fig. 5), and is fed from a roller (not shown) through a guide tube 37, I over the platform 38 and then, with the grids attached, through a further guide tube 48 to the front of the machine. The hooks 25, 34 are respectively attached to blocks 24, 30 which are pivoted on axles 23, 29. The raising and lowering of the blocks 24, 30 is by the horizontal movement of rods 55, 59 and their associated coupling components 53, 54 ; 57, 58. The downward movement of the block 24 causes a pecker 49 to grip the base strip 2 in tube 37 against a guide 51 and move it forward by an amount equal to the overall length of a complete grid. Platform 38 is raised by a cam 41 and rod 39 device operated by rotation of knob 45a, a number of similar devices shown in Fig. 5 may be mounted side by side, all being fed with wire from a common reel.