Patent GB-535169-A (GB)
Title: Hydraulic moulding press
IPC: B30B15/16
Filed: 1939-05-05
Abstract: 535,169. Moulding presses. SPENGLER, J. P. May 5, 1939. No. 13524. [Class 87 (ii) ] In a hydraulic moulding press wherein the article is moulded by a pressing piston l 1  working in an open mould in the press table the base of which is constituted by an expulsion piston s and the moulding is completed by an upward pressure exerted on the expulsion piston by the pressure accumulated in a hydraulic accumulator the expulsion piston being expelled whilst the pressing piston still contacts with the moulded article, the operation of the press is controlled solely by the to-and-fro movement of a filling slide a on the press table. The pressing piston l 1  in a cylinder l is combined with a smaller piston i in a cylinder h having a conduit i 1  therethrough communicating with the cylinder l and closed at its upper end by a valve k the valve rod j of which is provided with a projection w which is tripped during the motion of the pressing piston to admit pressure water through the conduit i 1  to the main cylinder l. A valve m is now opened by the suction to admit filling liquid. The pressure water is supplied to the cylinder h through a pipe g and by means of a conduit n pressure is built up in a hydraulic accumulator o ... q whilst the pressing piston is in operation. The hydraulic accumulator comprises a valve chamber p, closed by a spring- loaded valve o, in communication with a cylinder q, containing a strongly loaded piston q. The latter is connected to the underside of the piston s by a pipe r. The pipe r is connected by a branch pipe with the valve chamber of a pressure release valve f, Fig. 2, and the pipe g with the valve chamber of the pressure water control valve e, both of the valve chambers being connected to the exhaust conduit wand the valve e in addition to the supply pipe t. The valves f and e comprise screw-threaded pins with milled heads t 1 , t 2 , and in the neutral position are urged by springs h 1 , h 2  into the closed and opened positions respectively as shown. In this position, the pressure water flows direct from the conduit t to the exhaust u. The filling slide a is combined with driving members c, c 1 , Fig. 3, which engage with the heads t 2 , t 1  as the filling slide moves to and fro over the press table in channelled guides d, thus operating the valves e and f sequentially.. In operation after the filling slide has discharged its contents into the mould and it occupies the neutral position shown, Fig. 3, the slide is moved backwardly so that the driving member c closes the valve e and the pressure water flows through the pipe g to the cylinder h and the pressing cylinder is thus operated. The slide is then moved slightly forwardly to free the valve e to its open position thus connecting the pipe g with exhaust and enabling the pressure above the pressing cylinder to be released. This results in the valve o being closed and the pressure liquid collected in the hydraulic accumulator then presses the piston s upwardly to complete the process and to lift the article with the upper stamp still in contact out of the mould. The pressing piston is then returned to its original position by the springs x, x 1 . Finally the slide is moved farther forwardly so that the driving member c 1  opens the valve f to release the pressure water from below the piston s to the exhaust, the piston falling to its original position. This last movement of the slide pushes the moulded article from the press table.