GB563568A - Improvements relating to machines for moulding plastic materials, or for use in making die castings from metal - Google Patents

Abstract

563,568. Hydraulic presses. E.M.B. CO., Ltd., SMITH, S., and COCKERILL, W. H. Jan. 25, 1943, No. 1247. [Class 69 (ii)] [Also in Groups V and XXII] The movable platen e, Fig. 6, is advanced towards the fixed platen by pneumatic or hydraulic pistons i ; the rate of movement of the platen is controlled by an hydraulic ram m; and when the mould halves carried by the two platens have been brought together, a final pressure is exerted on the movable platen by a pneumatic or hydraulic piston-rod p which acts through the medium of the liquid in the ram cylinder h. Material cannot be injected into the mould before this final pressure has been exerted. As the platen advances, liquid escapes from the front of the ram cylinder to the back via valve s, Fig. 3, reservoir r and valve t. Valves 2, 3 and 4 control respectively the operating pistons i, the " intensifying " piston-rod p, and the means for injecting material into the mould. The valves 2, 3 and 4 are operated by manual movement of a spindle v carrying cams 8 and an arm 9. The valves s, . t are operated by levers z actuated by a cam spindle y which is connected by chain-and-sprocket gearing to the spindle v. The spindle v is formed, at different parts in its length, with flats 10, Fig. 3, and 10a, Fig. 5, which co-operate respectively with a flat part 11 on a bar 12 fixed to and travelling with the platen, and a flat part 13 on a spring- loaded plunger 14. Operation : (a) initial angular movement of spindle v actuates valve 2 to advance pistons i and platen e ; (b) a second angular movement opens valves s, t. This movement is terminated by abutment of flat 10 on flat 11. The platen advances : (c) when the platen stops, a recess 16 in rod 12 allows a third angular movement of spindle v to operate valve 3 and apply the intensifying pressure; this third angular movement is limited by abutment of flat 10a on flat 13 ; (d) when the pressure in the ram cylinder h reaches a predetermined value, it acts through conduit 20, Fig. 5, to force plunger 14 leftward, thus positioning a recess 15 in the plunger to allow a fourth angular movement of the spindle v, which results in actuation of valve 4 and consequent injection into the mould. When, through improper adjustment, the platen e moves too far, an abutment 22 on rod 12 moves lever 23 to open valve 24 and relieve the intensifying pressure. The hand lever (not shown), which operates spindle v, may co-operate with adjustable abutments as described in Specification 547,641. There may be only one (axiallyarranged) piston i.