GB705177A - Improvements in or relating to linear dimension and surface roughness gauging devices - Google Patents

Abstract

705,177. Linear-dimension gauges ; ganging surface roughness. SHEFFIELD CORPORATION. March 15, 1951 [March 16, 1950], No 6258/51. Class 106 (2) A device for gauging linear dimensions or surface roughness comprises a source 10, Fig. 1, of fluid under pressure connected to a leakage orifice 18 in a gauging head 15, the fluid pressure behind the leakage orifice 18 acting through pipes 19 on one side of a flexible diaphragm 20, Fig. 3, the other side of which is open to atmospheric pressure at 26 but varies by its displacement the rate of flow of air from an air leakage nozzle 27 adjacent to and discharging against this said other side of the diaphragm 20. The resulting pressure changes behind the air leakage nozzle 27 are an amplified measure of the pressure changes behind the leakage orifice 18. These amplified pressure changes may be gauged by suitable means or they may act on pressure controlled electric switches 38, 39, 40 connected to the nozzle 27 by a pipe 28. The pressure behind the leakage orifice 18 may act on more than one diaphragm, each diaphragm controlling an air leakage nozzle and each air leakage nozzle may be connected to its own group of pressure controlled electric switches. With such a plurality of diaphragms, the normal spacing between each nozzle and its adjacent diaphragm differs from that of the others. In Fig. 1, the source 10 of fluid pressure to the pipes 19 and 28 is made through pressure regulators 11, 12, 32 and adjustable air restricting valves 13 and 34. As shown the pressure changes behind the orifice 18 also act on two flexible diaphragms in a casing 48, each diaphragm having an associated nozzle, one nozzle actuating the pressure controlled electric switches 63, 64, 65 and the other the switches 66, 67 and 68. The switches may control indicating or selecting means.