Patent GB-921910-A (GB)
Title: High energy, high velocity, impact machine
IPC: B21J7/34
Filed: 1961-04-12
Abstract: 921,910. Metal working hammers. U.S. INDUSTRIES Inc. April 12, 1961 [May 2, 1960], No. 13130/61. Class 83 (4). A high energy impact apparatus such as a forging hammer, comprises a pair of massive plates 22, 23 movable toward and away from each other by a driver mechanism interconnecting the plates and adapted to pull them together, the kinetic energy of the plates derived from the driver mechanism being used to form metal positioned between the plates. The plates carry dies 24, 25 and are movable between tie members 15, 16 secured to channelled guides 12, 13 by the drive mechanism which consists of one or more units 20, 21, each unit consisting of a cylinder 37 slidably mounted in a block 30 and secured to the lower plate 23. The cylinder is closed at its lower end by a cap 40 and its interior is connected by a tube 33, passage 31, 116 and a valve 117 to a gas or liquid source 120. The cylinder slidably receives a float 44 and a piston 55 connected by a post 60 to the upper plate 22. The piston has a bleed passage 57 interconnecting its upper and lower faces and the upper face has a surface 69 for sealing engagement with a seating 61 resiliently mounted in a chamber 54 in the lower plate. The post 60 is extended to form a rod 99 and piston 104 in a cylinder 89 which form means for charging, cocking and supporting the driver mechanism. The space above the piston 104 is connected by a line 121 and valve 122 to an hydraulic accumulator 123 and pump 124 and the space below the piston is connected by a port 103 and line 112 to a valve 113 and source 115a of gas, the latter space also being connected to the interior of the cylinder 37 by a passage 108 in the rod 99 and post 60. In operation and with the parts in the position shown, corresponding to the position just before cocking, valve 113 is operated to connect the source of gas 115a to the cylinder 89 so as to maintain the piston 104 and hence plate 22, at the top of its stroke, and, by way of passage 108 to the cylinder 37 to cause piston 55 to engage the seating 61. When valve 113 is closed and valve 122 opened, the hydraulic accumulator 123 is connected to the upper surface of piston 104 which moves downwardly to unseat piston 55 from seating 61, valve 122 then being closed to lock piston 104 in cylinder 89 to prevent piston 55 re-engaging the seating 61. The gas pressure in cylinder 37 can now pass through the bleed passage 57 into the chamber 54 and when valve 117 is operated, the pressure from the gas or liquid source 120 acts in cylinder 37 to move float 44 upwardly compressing the gas in the cylinder 37 and in the chamber 54. Vavle 122 is then opened to connect the space above piston 104 to the reservoir 125 to permit piston 104 to move upwardly and piston 55 to sealingly engage the seating 61 to close the connection between the cylinder 37 and chamber 54 and valve 117 is opened to vent the space in cylinder 37 beneath the float. The plates can be brought together for the operative stroke by operating valve 122 to connect the accumulator 123 to piston 104 which moves to displace piston 55 from seating 61, the pressure in chamber 54 acting on the piston 55 and the upper surface of the chamber to drive the plates toward each other, the speed at impact being about 50 feet per second. Each plate may weigh 500 lbs. and the energy, which may be 25,000 ft. Ibs. imparted to the plates acts on a workpiece between the dies 24, 25. The pressure in cylinder 89 then acts on piston 104 to move the plate 22 upwardly, the final movement being damped by hydraulic fluid being compressed in a recess 95 by a projection on the piston 104. The drop of the plate 23 to its lower position is damped by flow of gas through the bleed passage 57 in piston 55. In an alternative arrangement, the chambers 54 are charged by a source of gas 81 connected to the chambers by a valve 18 and line 77. The plates may be arranged to move horizontally.