GB217629A - Improvements in forging presses or like machines - Google Patents

Abstract

217,629. Massey, Ltd., B. & S., and Massey, H. F. March 9, 1923. Metal-working presses.-An eccentric- or crank-operated press has the reciprocating motion transmitted to the head through one or more confined masses of liquid the volume of which may be varied to adjust the mean position of the head. If desired two masses of oil or water may be employed and are contained in a cylinder 11 on either side of a piston 23 reciprocated by the crank 15. Rotary or sliding valves 41, 42 normally close ports 38, 39 but may be moved in either direction to connect one of the ports directly and the other through inlet valves 43, 44 to a reservoir 33 so that one of the liquid.. masses increases and the other decreases causing an adjustment of the cylinder 11 which forms the press head. The movement of the valves 41, 42 is effected by a treadle 51 through a floating lever 47 connected at its middle point to a lever 54 connected to the piston rod 22 and to a short lever 55 pivoted to the frame. By this arrangement the valves 41, 42 always move in unison with the piston 23 and, until the treadle is operated, with the cylinder 11 so that. the adjusting movement of the cylinder brings it into the normal position relative to the valves 41, 42 and the adjustment ceases. In the case of a vertical press the head may be balanced by a weight 32. If the pressure of the head on the work becomes excessive safety valves 57, 58 leading to and from the reservoir open. If only one fluid mass is employed the control valve is arranged to connect it to the reservoir through an inlet or outlet according as it is moved in one direction or the other. In another modification the head 86, Fig. 7, is carried by a piston 81 in a fixed cylinder 79 both ends of which are constantly connected to a cylinder 78 containing a crank operated piston 80. Valves 97, 98 are arranged so that when moved from their midposition they connect the oil spaces above and below the pistons with the reservoir 33 as in the first modification. These valves are moved by the treadle 51 through a floating lever 102 whose middle pivot 105 is connected to a lever 107 pivoted to the head 86 and engaging a recess 108 in the crank-operated piston rod 82. In another modification the pistons 80 and 81 may be arranged in the same cylinder. The reservoirs are so arranged about the valves &c. as to prevent air from entering the oil spaces. If the areas above and below a double acting piston 23 or 81 are equal the valves may be arranged to connect the oil spaces directly and a reservoir is not required.