GB762164A - Improvements in or relating to pneumatic linear dimension gauges - Google Patents

Abstract

762,164. Pneumatic linear-dimension gauges. SIGMA INSTRUMENT CO., Ltd. Sept. 14, 1955 [Dec. 30, 1954], No. 37674/54. Class 106 (2) A pneumatic gauge .comprises a gauging jet 19, Fig. 1, for co-operating with a workpiece 20 to be guaged, a pressure indicating device 12, an air supply pipe 3 leading through a constriction 14 to the jet, a conduit 15, 17 between the device 12 and the pipe 3, a valve 16 in this conduit and means controlling the valve 16 so that when a workpiece is in gauging position the valve is open and when there is no workpiece in gauging position the valve is closed, whereby when the workpiece is removed from gauging position the valve is closed before leakage of air from the jet 19 changes thus enabling the device 12 to maintain its indication after the workpiece is removed. Preferably the device 12 consists of a manometer tube connected by a conduit 6 through an orifice 5 with the air supply, an adjustable valve 7 controlling leakage to atmosphere being provided. As shown, the valve is controlled pneumatically by means of a monitor. ing jet 25 associated with the workpiece 20, supplied with air through an orifice 22 and conduit 4 and connected by a further conduit with the valve 16 the arrangement being such that the reduced leakage of air from the jet 25 in the presence of a workpiece causes the valve 16 to open. Alternatively electromagnetic means may be provided for controlling the valve 16. As shown in Fig. 2, the valve 16 comprises a Schrader tyre valve housed in a cylindrical casing 26 connected at 15 to the gauging jet 19 and at 17 to the manometer 12. The end 32A of the valve pin 32 abuts against a push rod 38 slidably mounted in a mounting 24 and whose other end is in contact with a flexible membrane 39 whose opposite face co-operates with a further push rod 42 whose other end contacts a diaphragm 43 subjected to the pressure in the conduit 4. When a workpiece 20 is correctly positioned the leakage from the monitoring jet 25 decreases and the pressure in the conduit 4 increases to deflect the diaphragm 43 to move the rods 38, 42 in the direction to open the valve 16, the pressure at the gauging jet being then fed by inlet 16 to the manometer via outlet 17. Specification 724,205 is referred to.