Patent GB-353165-A (GB)
Title: Improvements relating to retarding or pressure-controlling devices
IPC: B21D24/02
Filed: 1930-05-30
Abstract: 353,165. Shock - absorbers. CARTER. A., 166, Poplar Avenue, and LEES, J., Chaddesley, Meadow Road, both in Edgbaston, Birmingham. May 30, 1930, No. 16684. [Class 83 (iv).] Cupping.-In a fluid-pressure buffer for metal-stamping presses, vehicle shock-absorbers, gun resistance buffers, aeroplane landing devices, &c., the fluid oil is forced from one cylinder into another cylinder through orifices which are varied as the piston descends, and at the end of the stroke a spring-pressed plunger returns the fluid to the first cylinder to reset the buffer. As applied to a cupping press the draw ring 1 depresses the piston 5 which forces oil through the registering slots 24, 27 of the sleeves 22, 26 so that it flows to the top of the plunger 9 in the secondary cylinder 8, this plunger 9 being thereby depressed against the resistance of a spring 14. The effective opening area of the registering slots 24, 27 is made either to increase or decrease as the piston descends by suitable design and by the sleeve 26 being attached to and moving with piston 9, the initial setting being made by rotating the sleeve 26 by hand-lever 35. When the cupping pressure on the draw ring is removed, the spring 14 presses piston 9 up. Any oil which escapes past the piston rings collects in the sump 48 whence it is pumped by a plunger 51 through the valve 63 and passage 68 to the cylinder 8; the plunger 51 being coupled by arm 56 to the piston 9 to move with it. In a modification, the sleeve is attached to and moves with the upper piston and is set relative to the other sleeve by an arm, a pin and slot allowing of this. In another modification the sleeve moves with the upper piston and the sleeve 26 moves with the lower piston to give an increasing effective slot area and so give diminishing resistance. The sleeves may be replaced by a cone valve 80, Fig. 12, moving with the lower piston 9 to increase the exit for flow of oil from the top cylinder to the top of lower piston 9 as the piston 9 descends. The initial opening can be set by raising or lowering this valve 80. The cone valve 80 may be inverted to obtain an increasing resistance buffer. Quick return of the fluid to the upper cylinder after the end of the stroke is allowed through passage 84, valve 39, and bore 85. In very heavy presses where the spring 14 would not be strong enough to return the draw ring, it is positively raised by the ejector rods 88, Fig. 13, also raising a boss 86 to press up the piston 9, preferably through a spring 89 which allows the top of the piston 9 enough freedom to set itself centrally against the slope 19, Fig. 1, of the cylinder top. In Fig. 14 the secondary piston is raised by air pressure instead of a spring. On the drawing stroke piston 5 descends forcing fluid (oil) through the slot 24 into sleeve 22 and thence through the overlapping ends of slots 24, 27, into the annular space 91, thence into chamber 97 thereby compressing air in the elastic walled air chamber 96. At the end of the working stroke the air pressure in chamber 96 forces the oil back past valve 39 into the top cylinder 4. A sump 48 receives leakage oil which is pumped back by a plunger 51 operated by links 111 coupled to the top piston 5. Specification 304,838, [Class 108 (iii), Springs &c.], is referred to.