Patent GB-461678-A (GB)
Title: Improvements in fluid-operated balancing systems for fluid pressure hammers, drop stamps and the like
IPC: B21J7/24
Filed: 1935-08-19
Abstract: 461,678. Fluid - pressure hammers. TOWLER, F. H., and TOWLER, J. M. Aug. 19, 1935, Nos. 23296 and 25782. [Class 122 (iii)] [Also in Group XXII] In a fluid operated balancing-system for fluid-pressure hammers, drop stamps, &c., a mass which oscillates about a predetermined mean position has supporting means comprising a balancing-cylinder and piston and a receiver containing elastic, pressure fluids which acts in opposition to the weight of the mass and balances it in the desired mean position. The pressure in the receiver is automatically controlled by tappet-operated lift valves to correct displacements due to leakage, change in weight, &c. In the arrangement shown in Fig. 1, the receiver 1 is connected by pipes 2, 3 to the balance cylinders 4, 5 and pistons 6, 7 which support the crosshead 8 carrying the usual valve-gear. A hammer piston 9 is attached to the cross-head 8 and works within a cylindrical tup 10 and is operated by steam or air. Columns 11, 12 depend from cross-head 8 and are supported by nuts 13, 14 and resilient washers 15, 16. The columns guide the tup 10 and carry the anvil block 17. Should the oscillation of the beam 8 fall below a certain point, a valve 18 is raised from its seat and fluid-pressure is admitted to the receiver 1. Should the moving mass be lightened so that its centre of oscillation rises, a second valve 23 is opened to reduce the receiver pressure. A modification is described with a piston tup, the cylinder being secured to the beam. The valve 18 may be dispensed with, and the receiver receive a small constant supply of fluid. In the arrangement shown in Fig. 3, the frame and anvil are supported on a single balance piston 26 in a balance cylinder 27 filled with oil under pressure supplied by a pipe 28 connected to the air receiver 29. The change of pressure in the receiver keeps the centre of oscillation above a given level. Oil is supplied to the cylinder 27 by a pump 30 and is fed from receiver 31 fed with leakage oil from the cylinder 27. The valve 33 serves the purpose of the. valves 18, 23, Fig. 1. The pump delivery is equal to or in excess of the oil leakage, so that the frame and anvil are maintained at the upper end of their oscillation. If the piston 23 tends to rise, the abutment 20 raises the valve 33 and byepasses the pump discharge to the tank 31. To prevent a hunting action, catches &c. may be provided to hold the spindle 34 up when the hammer oscillates at the upper limit, the spindle being released by a tappet and the valve 33 made to close by a weight 35 when the anvil and hammer frame begin to oscillate below the lower limit. In a modification, the pump continually supplies oil to the cylinder, and a tappet-operated valve controls a discharge therefrom to the tank. In a further modification, the balancing-pistons are stationary and the cylinders reciprocate and are connected to the mass by links. When the anvil moves too low, a plunger valve is .opened against the resistance of a spring and passes fluid from the receiver to the cylinders.