| 摘要 |
1,157,897. Valves. HUCK MFG. CO. 10 Oct., 1966 [23 Oct., 1965], No. 45256/66. Heading F2V. Pressure signals, for actuating a rivet installation rod, are derived from passages 30 and 32, connected to a supply not shown, in response to reciprocation of a piston 26 formed on a shaft 24 connecting two further pistons 20 and 22, the latter pistons being pneumatically actuated. Within a housing 12 there are formed two cylindrical cavities 14 and 16 interconnected by two bores 17 and 18, the first being axially situated and containing the piston connecting shaft 24, and the second being axially offset and housing a valve 42. The valve comprises a fixed housing member 44 and, movable within it, a closure member 86. Two annular grooves 128 and 130 formed within member 86, are arranged to connect either one of ducts 60 and 64 with duct 62 and either one of ducts 64 and 68 with duet 66 respectively, all ducts being formed within the housing. Ducts 60 and 68 are permanently connected to exhaust through lines 72 and 74, whilst duct 64 is similarly connected to a pressure line 76. Thus, in the position shown, exhaust 72 connects, via duct 60, groove 128, and duct 62, with line 40 which opens into the two cavities 14 and 16, and pressure 76 connects, via duct 64, groove 130 and duct 66, with line 38 which likewise opens into the two cavities. As a result the pistons 20 and 22 are caused to move in unison downwardly. Towards the end of this movement, the upper piston 20 strikes the stem 92 of a piston 96, housed within the closure member 86 and biased by a spring 98 against a stop 100, with the result that the piston is moved downwardly until a sufficient force is built up to move the closure member out of its position shown and into its lowermost position, this force being necessary to overcome the resistance to movement provided by detent means 116, the means comprising a ball and cap 120 and 124 biased by a spring 126 into engagement with either one of two grooves 112 or 114. Thus, when the closure member is moved into its lowermost position, as determined by the registry of ball 120 with groove 114, the pressure line 76 is connected to line 40 and exhaust 74 to line 38 thereby reversing movement of the pistons 20 and 22, with further reversal occurring when piston 22 strikes stem 102. |
