GB710718A - Improvements in or relating to distributing valves for pneumatic pressure responsive apparatus - Google Patents

Abstract

710,718. Pneumatic presses. SMALLPEICE, Ltd. Oct. 13, 1952 [Oct. 31, 1951], No. 25422/51. Class 122(3) [Also in Groups XXVIII and XXIX] Control of supply of compressed gas to a pressure responsive means e.g., a valve 11, Fig. 1, in a compressed gas supply pipe 12 of a pneumatic press comprising a piston and cylinder 16, 17 is effected by two control valves 14, 15 comprising two movable members 38, 46, Fig. 4, which in one position connect the valves 14. 15 in series between a reservoir 13 and the supply pipe 12 and when simultaneously moved to an alternative position connect the reservoir 13 to the pressure responsive valve 11, movement of one control'valve only to the alternative position serving to connect the reservoir to exhaust. In the valve positions shown gas from the pipe 12 traverses the valve 11 and pipes 19, 20 to effect the return stroke of the piston 17 which exhausts through a pipe 21 and the valve 11, and during this return stroke the reservoir 13 is charged from the pipe 12 through pipes 26, 27, ports 43, 41 of the valve 15, a pipe 28, ports 35, 34 of valve 14 and pipes 29, 30. On depressing valve buttons 39, 47 simultaneously the reservoir 13 discharges through pipes 30, 31, ports 36, 37 of valve 14 and a pipe 33 to displace a piston 66, Fig. 5, of the valve 11 against a biasing spring 75 to allow air to flow from the pipe 1 through valve ports 12a, 22a and pipes 22, 21 to effect the forward stroke of the piston 16 which exhausts through pipes 20, 19 and valve ports 19a, 62. On completion of the forward stroke, pressure built up against the working force of the piston 16 and in a pipe 85 depresses a valve piston 116 to gain access to a pipe 86 to depress a valve 80 so as to relieve the pressure beneath the valve member 66 to exhaust through pipes 33, 68, 81. The valve 11 then assumes its biassed position wherein it provides access of pressure gas to the piston 16 to effect the return stroke. but no further piston movement can occur until valves 4, 15 are released and the reservoir is subsequently recharged. In a modification the forward stroke of the piston is effected pneumatically as described above but the return stroke is effected by a spring; the pressure built up against the piston being exhausted through the valve 11 after it assumes its biased position. In a further modification wherein the return stroke is effected by spring pressure beneath the control valve, piston 66 is exhausted by connecting pipe 33 with the exhaust port of a.valve operated by a cam driven from a member moving with the piston 16.