| 摘要 |
779,747. Pneumatic gauges. SHEFFIELD CORPORATION. June 17, 1955 [June 18, 1954], No. 17538/55. Class 106 (2). A pneumatic gauging apparatus, of the kind wherein the workpiece is placed between two opposed outlet nozzles for compressed air, comprises a diaphragm 17, passages 12, 14 in communication with each side of the diaphragm and adapted for connection at 11 to the gauging system, a one-way check valve, e.g. consisting of a ball 31 in a valve seat 32, in one passage allowing free flow to the associated side of the diaphragm but preventing fluid escape therefrom and gauging means, e.g. a switch 42 operative upon a predetermined movement of the diaphragm 17. As the pressure in the system rises air passes through the valve 31 into a chamber 21 and the diaphragm 17 is kept in equilibrium. As the pressure begins to fall in the passages 12, 14, the valve 31 closes and the diaphragm 17 rises and forces upwards a pin 40 which is secured to an electrical contact arm 36 which, when in contact with an arm 4T, closes a lamp circuit. The lower arm 41 is adjusted beforehand by a screw 44 so that if the allowable tolerance is exceeded the lamp is extinguished. When the workpiece is removed the pressure falls and a projection 34 on a diaphragm 22 returning to its equilibrium position from which the pressure had displaced it, moves the ball 31 from the valve seat 32 releasing the pressure in the chamber 21, thus resetting the apparatus in readiness for the next workpiece.
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