GB388566A - Improvements relating to metal working presses - Google Patents

Abstract

388,566. Cupping- presses. FITZPATRICK, H. D., 94, Hope Street, Glasgow.-(Marquette Tool & Manufacturing Co.; 6500, West 65th Street, Chicago, U.S.A.) Feb. 18, 1932, No. 4786. [Class 83 (iv).] A metal-working press comprises an upper reciprocating ram and a pressure pad whose movement is yieldingly resisted by a fluid-pressure cushion having a controlling valve which is normally held on its seating by fluid pressure, until this pressure is overcome by pressure in the cushion. In a double acting press, a ram 13 carrying a die 21 is reciprocated by links 17 connected with a crank shaft 15 while a co-operating central die 20 is connected by link 19 to a second crankshaft 18. Mounted on the base 10 is a baseplate 23 which supports a die 24 enclosing a second die 25 which rests on a pin 26 supported on a pressure member 27 connected to the piston 28 of a hydraulic cylinder 29. A valve casing bolted to this cylinder is provided with a valve 36 controlling the flow between the cylinder and a pipe 45 leading to a pressure reservoir 43 to which air or similar fluid pressure may be admitted from a pipe 47 through a pressure regulating valve 48. Fluid from a branch from the pipe 47 also flows along a pipe 52 to a valve casing 54a and thence through a pipe 42 to a cylinder 40 having a piston 39 connected to the valve 36 which is normally held on its seating by the pressure in the cylinder 40. The stem of valve 36 also carries a piston 38 of a diameter intermediate between the diameters of valve 36 and piston 39. The hydraulic pressure in the pipe 45 acts on the piston 38 to tend to open the valve against the normally greater seating pressure of the piston 39. The cylinder 40 is controlled by a pair of automatic valves 56, 59 mounted in the casing 54a and actuated through a rocker 70 from a cam 68 on a member 67 driven by a chain 73 from part of the main driving gearing 22. When valve 56 is opened the pipe 42 leading to cylinder 40 is open to the fluid pressure in the pipe 52 but when valve 56 is closed and valve 59 is open the pipe 42 is in communication with a passage 61 open to the atmosphere. The valve 36 can then be unseated by the hydraulic pressure on the piston 38. In operation during the approach of the ram to the work the parts are in the Fig. 1 position, the valve 36 being seated by the adjustable pressure in the cylinder 40. As the die operates on the work the piston 28 is forced downwards and the increasing pressure finally opens valve 36 and liquid escapes through the pipe 45 to the container 43. When the ram ascends the reservoir pressure on piston 38 opens the valve 36 and restores the piston 28 to its upper position whereupon the valve is seated by pressure admitted to the cylinder 40.