GB1237784A - Hydraulic apparatus - Google Patents

Abstract

1,237,784. Injection moulding. P. FLORJANCIC. 5 Aug., 1968 [3 Aug., 1967; 29 Sept., 1967], No. 37300/68. Heading B5A. An injection mould 10, 11 with an injection head 12 and an article ejector 13 is closed in two stages by an hydraulic drive mechanism including a piston 5 spaced from the walls of a pressure chamber 6 and connected by rods 9 to the movable part 11 of the mould, and a valve piston 30 sealingly slidable in a chamber 7 connected to the chamber 6 by a bore 40. An outflow line 18 from the chamber 7 leads to a supply container and is closed by a valve. When pressure fluid is fed to the chamber 6 via line 17 the main closing stroke of the piston 5 is effected to bring the pistons 5, 30 together, in which position they are sealed together by a sealing ring 35. During this movement the piston 30 is held in position by a pin 32 adjustably located axially by a screw 31. With the pistons sealed together a switch 21 is operated by a pin 20 whereby the valve in line 18 is opened and a final mould closing movement effected. The mould is opened by hydraulic pistons 14. The chamber 6 and piston 5 may be of any desired crosssectional shape. In a modification the seal between the pistons embraces the push-rods 9, in which case the latter extend through the piston 30. The sealing surfaces between the pistons may be frusto-conical or cylindrical, and in the latter case, Fig. 8, the piston 5 may slide within a sleeve portion of the piston 30.