GB1302095A - - Google Patents

Abstract

1302095 Forging MASCHINENFABRIK SACK GmbH 25 March 1970 [5 April 1969] 14552/70 Heading B3H A multi-die forging machine has each die 1-4 driven by a working cylinder 11-14 connected to its own pump 57-60 whose piston 61-64 is mechanically coupled to the other pump pistons for synchronous reciprocation, the return stroke of the pistons being effected by a constant hydraulic pressure. The pump pistons are connected to a crosshead 65 driven by a crank 67. The dies 1-4 are pivoted about axes parallel to the direction of movement of the workpiece 5. The return stroke of the working pistons 15-18 is effected by piston-cylinder units 43-46 connected to a pressure storage vessel 50. The piston-rods 39-42 of the return stroke units are pivoted to the dies which are also connected to electric position transmitters 31-34. The signals from these transmitters are applied to positioning motors 27-30 for screw adjustable stops 19-22 for the working pistons. The motors can be individually operated to alter the end of the stroke and hence the workpiece crosssection. Near the end of the return stroke the hydraulic lines 53-56 from the pumps to the working cylinders are drained to a tank 52 through lines 81-84 with valves 76-79 controlled by cams 72-75 on the crank-shaft 71. The lines 53-56 are refilled by a low-pressure pump 85. The replacement of working fluid removes heat from the working cylinders and compensates for any leakage. In a similar embodiment, Fig. 2 (not shown), the pump pistons (61)-(64) are connected in pairs to a pair of crossheads (65) each driven by a crank and connected by a shaft (103). Alternatively each pump piston may be driven by its own crank and the cranks are connected mechanically together. To prevent overloading of the machine each line (53)-(56) contains an hydraulic accumulator (108)-(111) in which fluid can be temporarily stored. The fluid circuitry also includes a recycling device controlled by a normally closed magnetic valve (118). The recycling device provides recycling of fluid when the machine is inoperative to replace hot working fluid. The machine may have an auxiliary flushing pump. Reference has been directed by the Comptroller to Specification 1,164,657.