| 摘要 |
657,922. Pneumatic gauging apparatus. SHEFFIELD CORPORATION. April 8, 1949, No. 9602. Convention date, April 28, 1948. [Class 106 (ii)] Apparatus with work-engaging means having a plurality of fluid discharge passages the flows through which are controlled by different workpiece dimensions to be compared comprises a pressure responsive element connected to each passage for gauging the fluid flow therethrough and means responsive to relative movement between arms attached to each element to show an out-of-tolerance condition between the dimensions. A passage 11 of form corresponding to the workpiece to be gauged and slightly greater in diameter has three annular grooves 13, 14 and 15, the grooves 13, 15 communicating with the outside air and groove 14 with a pressure chamber 19 supplied with air through a pressure regulating valve 21 and passage 22 restricted at 23 so that the pressure in the chamber 19 accords with the flow through the groove 14 and thence between a workpiece under test and gauging surfaces 24 a few ten-thousandths of an inch larger in diameter than the passage 11 and depends on the average diameter of the piece. A similar pressure chamber 28 and grooves and valve are arranged near the other end of the passage 11. Two Bourdon tubes 38 mounted in a gauging head 32 attached to the base 10 by bolts 35 communicate with the chambers 19, 28 through hollow posts 39 and passages 40 sealed by rubber discs and carry arms 45, 55 attached to extensions 46, 54 and insulated therefrom by bushings and washers 48, 49. The arm 46 carries a contact 50, Fig. 4, which, upon a relative change in pressure in the chambers 19, 28, due to differences between the gauging surfaces 24, 26 in departure of the workpiece from a standard taper, moves between two contacts 51, 52 carried by the arm 54 adjusted according to the tolerance allowable by using a standard piece within the tolerance limits. If the dimensions are out of tolerance a circuit is closed to a lamp. The apparatus may be modified for testing out-ofroundness by connecting two pressure chambers such as 19, 28 respectively to two pairs of diametrically opposed nozzles.
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