Patent GB-801542-A (GB)
Title: Improvements in or relating to inspection machines for gauging the dimensions of workpieces
Inventor: LOXHAM JOHN
IPC: G01B13/00
Filed: 1955-05-05
Abstract: 801,542. Pneumatic single-stroke apparatus. SIGMA INSTRUMENT CO., Ltd. May 3, 1956 [May 5, 1955], No. 13100/55. Class 8(2). Dwell between the end of the forward stroke of a double acting compressed air actuated jack 2 and the beginning of the return stroke is determined by the time taken firstly to charge an air reservoir 82 up to 65 p.s.i. through a change-over valve 69 connected to a supply line 17 and secondly to discharge the reservoir down to 35 p.s.i. through the valve 69. Initiation of the forward stroke of the ram piston 4 carrying a workpiece from a loading position to a gauging position is effected by momentarily depressing a pedal 44 of a valve 31 connected to a branch 29 of line 17 and to a line 43 along which an air pulse passes to operate a piston 23A of a changeover valve 23 and thereby connect a branch 22 of the supply line 17 through said valve 23 and a line 76 to the end 3B of the ram the other end 3A being connected by a line 75 to an exhaust port 77 of the valve 23. At the end of the forward stroke the piston rod 5 opens a valve 52 to allow access of compressed air from a second branch 20 of the line 17 through an already open change-over valve 21 to a line 54 leading to the operating piston 35A of a change-over valve 35 which is then positioned to allow compressed air to pass from a line 34 through the valve 35 and a line 56 to the upper end of a vertical ram 6 which carries workpiece gauging clamps and a cam 10. Downward movement of the cam 10 first releases a valve 64 and finally opens a valve 41 through which passes compressed air from lines 20, 38, 39 to a line 70, the open change-over valve 69 and through arm variable orifice 80 to the reservoir 82. The latter is connected by a line 83 to the operating pistons of relay valve 93 . . . 97 and as the pressure rises to 35, 40 and 60 p.s.i. relay valves 95, 96, 97 are opened sequentially to provide access of compressed air to a pressure closing valve 117, a similar valve 36 for the operation of the gauges and the valve 97 for the operation of means for indicating the gauged dimensions. Finally when the reservoir pressure reaches 65 p.s.i. the valve 93 opens to pass compressed air from line 70 to a line 110, through an open valve 111 and a line 112 to open a valve 33 which connects a supply line 32 to a line 113 leading to the operating piston 69B of valve 69 ; the piston 69A being vented to atmosphere through the valve 64. The reservoir then begins to discharge through the line 71 and port 73 of valve 69, the relay valves 93 . . . 97 close as the pressure falls resulting in the opening of valve 117 which allows compressed air to flow from lines 70, 72 to a line 118 leading to the operating pistons 21B, 35B of change-over valves 21, 35. This results in the return stroke of ram 6 and the consequential opening of valve 64 which connects pressure lines 20, 50 to line 67 leading to the operating piston 23B of valve 23. Supply line 22 is thus connected to the end 3A of ram 2 to initiate the return stroke ; the other end 3B of the ram being connected to the exhaust port 77 of valve 23. A further cycle cannot be initiated until the pedal valve 31 is again actuated. The ram 6 may be held indefinitely at the end of its working stroke by opening a manually controlled valve 103 which when relay valve 94 opens at 40 p.s.i. connects the pressure line 70 to a line 114 leading through an open valve 47 to the control means of the valve 111 so as to keep it closed and thereby prevent access of pressure to valve 33 and change-over of the valve 69. Return stroke of ram 6 may then be initiated by momentary depression of pedal 44. The Provisional Specification describes a modification wherein the dwell is effected by controlled leakage from a timing cylinder. Specifications 724,205 and 746,900 [both in Group XIX] are referred to.