GB655091A - Improvements in or relating to shaping machines and like machine tools - Google Patents

Abstract

655,091. Shaping machines. ROCKFORD MACHINE TOOL CO. March 12, 1948, No. 7571. Convention date, May 15, 1947. [Class 83 (iii)] [Also in Group XXIX] A shaping or like machine has means for reciprocating the ram comprising a lever arm pivotally mounted on the bed and connected to the ram, a cylinder mounted on the bed having a piston reciprocable therein, said piston being connected to the lever arm, and means for supplying hydraulic fluid alternately to the ends of the piston to reciprocate the piston and cause the lever arm to oscillate about its pivot and thereby to reciprocate the ram. The ram 22, Fig. 2, is reciprocated from an oscillating hydraulic cylinder 23 and double-acting piston 26. The latter is connected through a swivel joint 126 to a crosshead 45 adjustable along a lever arm 35 by a screw 40. The lower end of this arm is pivoted to the machine bed and the upper end is connected by links 55 to the ram. Adjustment of the cross-head 45 connecting the piston to the lever arm is effected by rotating the screw 40 by gearing 42 and 41, nut-like members 133, 134 being secured to the cross-head and engaging the screw. Rotation of the gear 42 may be effected by hand or by a hydraulic motor 44, Fig. 9. A cable 48 connected to the lower end of the screw drives an indicator on the side of the machine showing the effective length of lever arm. Hydraulic circuit.-Pressure fluid is supplied from a constant displacement pump 60, Fig. 9, through conduit 61 to a selector valve 62. In the position shown, fluid passes through an opening 75 to a four-way valve 73 and thence by conduit 95 to the cylinder 24 to drive the piston of the ram-actuating mechanism on its forward stroke. A back-pressure valve 108 is fitted in the return circuit to ensure smooth operation. Adjustable dogs 99, Fig. 12, are set to trip a valve 100, 101 at the stroke ends to permit fluid from the pump to move the valve 73 to its alternate positions and thus reverse the flow of pressure fluid to piston 26. Reversal may be effected manually at any stroke position by hand-operation of the valve 101, through a lever 106, Fig. 12. When the selector valve 62 is moved manually to its alternative position a more rapid stroke of the ram is obtained. The work-table of the machine is given an incremental feed at each reversal of valve 73 by means of an auxiliary piston and cylinder device 109 which operates a rack and pinion 110, 111, respectively, the latter driving the required feed mechanism through a ratchet or similar device.