GB1150116A - Improvements in or relating to machines for producing articles by injection-moulding - Google Patents

Abstract

1,150,116. Injection moulding machines. DESMA-WERKE G.m.b.H. 17 Nov., 1966 [18 Dec., 1965], No. 51461/66. Heading B5A. The invention relates to an injection moulding machine for producing footwear &c. of rubber, plastics &c. and comprising a turntable (10), Fig. 1 (not shown), carrying a plurality of moulds 11 each including a core (16), and two lateral parts 13, 14 and a cover 15 articulatedly connected together. According to the invention the moulds are clamped at an injection station by means of two frames 17 in the interior of which are hydraulic pressure devices 18, 18C for applying pressure to the parts 13, 14 and cover 15 respectively. The frames 17 have ball-joint mountings 21 and are reciprocated vertically by hydraulic cylinders 20, 20d. Fig. 7 (not shown) shows a circuit for operating the cylinders 20, 20d, including a pressure source (23), slide valve (33) and pressure limiting valve (25) and means for compensating leakage. Pressure source (23) also supplies fluid for the high pressure devices 18, 18C. Each device 18 comprises a booster 35 (see Fig. 6, not shown) associated with a plurality of rams 37 arranged in a common housing 36 (Fig. 5). The booster 35 is controlled by a non-return valve (38) which can be released by a piston drive (39). Initially low pressure oil opens valve (38) and passes to the rams 37 which advance to abut the mould parts. A piston (47) of the booster 35 is simultaneously moved to the right in Fig. 6 (not shown). By appropriate setting of valves (40, 43) a piston (48) of the booster 35 is charged by the source (23) to cause high pressure mould locking by the rams 37. Each ram 37 comprises a piston 52 having a pressure head 58 loosely retained on a spherical surface of the piston 52 by a bolt 59. The piston 52 is advanced against the action of a spring 55 and is prevented from over advancing by a safety valve 54. A pressure plate 62 for engaging the mould cover 15 is slidably and tiltably mounted to accommodate deviations from an exactly normal mould position. Thus the plate 62 which has an opening 61 for an injection head (12d) is displaceably held on a mounting block 70 by means of a guide rod 77 and three pairs of rollers 73, 74, 75 (Fig. 3). The mounting block 70 is itself mounted on a swivel bolt 69 and held in a mean position by oppositely acting springs 66, 67 (Fig. 4). When the clamping frames are moved towards each other the pressure plate 62 is moved towards the cover 15 by the engagement of rollers 63 with rails 65 on the plate 62 (Fig. 2).