GB687003A - A process and a power hammer for swaging steel - Google Patents

Abstract

687,003. Forging. BECHE & GROHS GES. Feb. 27, 1950 [Oct. 1, 1948; Feb. 25, 1949], No. 4983/50. Class 83 (iv). In a process for forging steel by means of a gaseous pressure-operated ram, the rate of striking is selected so that the heat generated as a result of the impact of the ram on the work will substantially compensate for the normal heat losses of the work. Die wear is stated to be thereby reduced, and use of a relatively smaller hammer is possible. A steam hammer constructed to operate at the required rate, i.e. 300 blows per minute or more, comprises a cylinder 3, ram 4, and a regulating slide valve 10 actuated by a lever 40 pivoted on the machine frame and connected to a rod 41 engaging a slide shoe 49 on a bar 43 maintained in continuous oscillation by a motor 46. The lower end of the rod 41 is pivotally mounted and longitudinally slidable in a shoe 50 carried by the rod 51 of an auxiliary control piston 52, whose movement varies the point of engagement of the rod 41 with the oscillating bar 43 and therefore varies the stroke of the valve 10. The piston 52 is actuated by a rod 57 under the control of the operator, which moves a slide valve 59 through a lever 58 to allow pressure oil delivered through a pipe 53a to operate on the piston. The lever 58 is pivoted on the piston-rod 51, thus if the valve 59 is moved by operation of the rod 57 so that the piston 52 moves, the valve 59 is moved in the opposite direction to close the pressure oil channels, and the piston 52 comes to rest. To safeguard against failure of the control gear and consequent overloading of the hammer, a throttle valve in the steam supply line is held open against spring pressure by a piston actuated by pressure supplied by a pump whose drive is connected with the control gear so that with decrease of speed of rotation of the control gear, the spring overcomes the oil pressure and the throttle valve closes, Fig. 4 (not shown). The upward movement of the ram is cushioned by a spring-loaded piston above the main cylinder 4 and behind which steam is introduced.