| 摘要 |
1485393 Scratch strain gauge and recorder; recording apparatus LEIGH INSTRUMENTS Ltd 11 Nov 1974 [19 Nov 1973] 48681/74 Headings G1J and G1M A workpiece 36, Fig. 1, in which strain is to be measured, has blocks 12 and 34 fixed to it which support separate plates 10, 30 which are relatively movable in a longitudinal direction. The plate 10 mounts a double linkwork bifurcated beam 22 having extension 24, 26 each adapted to engage with an out-turned end of a two coil spring arrangement wound around a grooved disk on the end of a shaft 40 rotatably mounted in a housing 28 screwed down on to the plate 30. As the plate 10 in strain operation slides relatively to the plate 30 the end 16 mounting the beam 22 is caused to lift or fall slightly so that the ends 24, 26 of the beam in Fig. 2 lift or lower the ends 94, 96 of two single coil springs wrapped around and seated in grooves 100, 102 in a disk 98 fixed to the shaft 40. The springs are arranged to tighten and loosen respectively on the disk so that up or down motion of the ends 24, 26 produce rotation of the shaft 40 in one direction only. As the shaft rotates, a tape in an assembly 50 locked to an end-plate 52 of the housing 28 is rotated and unwound by a capstan roller 64, Fig. 3, fixed to the end of the drive-shaft 40. A stylus 20 fixed to the strain recording plate 16 may make a zig-zag trace D such as that shown in Fig. 4, the transverse distance between any two points being proportional to the change in strain, whilst a further stylus 48 on the housing 28 produces a datum line E to indicate what unwanted transverse movement of the tape has taken place. Fig. 5 (not shown), illustrates a slightly modified form of bifurcated beam. |
