Patent GB-1166081-A (GB)
Title: Improvements in or relating to Injection Moulding Machines
Inventor: FISCHBACH ALFRED
IPC: B29C45/67
Filed: 1966-09-09
Abstract: 1,166,081. Injection moulding machines. A. FISCHBACH. 9 Sept., 1966 [9 Sept., 1965; 5 April, 1966], No. 40485/66. Heading B5A. An injection moulding machine comprising a pair of platens 1, 2, each carrying a mould section 1a 2a, and drive means to effect relative displacement of the platens to open and close the mould, is provided with at least one hydraulically actuated clamping unit S operable, after closing of the mould, to force the platens together under mould sealing pressure. The or each clamping unit comprisesa pistoncylinder component K-Z (Fig. 5), and a transmission component B which can be locked in position relative to the movable element of the piston-cylinder component. One of the components K-Z or B is mounted on one of the platens 1 or 2, and the other on the other platen or on a fixed element of the machine. First embodiment.-In the example shown in Fig. 1, initial closing of the mould is effected by an electric motor 5 through a crank drive 4 and pusher bar 3. Sealing and clamping of the mould halves is initiated after mould closing by clamping of posts B by clamping units S. The platens 1, 2 then move into engagement with a nozzle of an injection cylinder 6, to effect injection by a spring-mounted plunger 7. Each clamping unit S comprises a sleeve Z (Fig. 5) bolted to the platen 2, the sleeve Z housing an axially reciprocable piston K with a part H of reduced diameter, cup-springs 12 urging the piston K towards the platen 2. The part H is rendered flexible by radial, longitudinal machinings (15), (16), Fig. 6 (not shown), and grooves 17 and is separated from the sleeve Z by a chamber 10 communicating with a chamber 11. When the mould is closed hydraulic fluid admitted to the chamber 10 through a conduit 8a first flexes the part H into frictional engagement with the post B, then acts on the piston K to move the latter and the post against the springs 12 to effect mould sealing. A tell-tale 14 indicates movement of the piston. After moulding, release of hydraulic pressure releases the post B, which is retracted with the platen 1 and allows spring-urged retraction of the piston K. Modifications.-In Figs. 3, 4 (not shown), initial closing is effected by a double acting piston (D) and cylinder (E). Modified constructions of clamping units S are shown in Figs. 7-18 (only Fig. 17 shown). In Figs. 7 to 9 the part H of piston K in Fig. 5 is replaced by a tubular rubber diaphragm (20) surrounding two semi-cylindrical gripper portions (18, 19) and held at one end between a piston element (Ka) and wedges (20a). The portions (18, 19) may be replaced by three or more portions or by a one-piece inner shell. In Figs. 10-12, the post (B<SP>1</SP>) is formed with a groove (32) having a forward shoulder (32a) against which each claw (31) of four followers (29) seats to effect locking of the piston (25) and post. In a similar embodiment, Figs. 16-18, each follower 29<SP>1</SP> comprises arms 36 engaged by the front face 37 of the post B<SP>1</SP>, and claws 31 seating against a shoulder 32a thereof in the mould closed position, the followers being spring-biased to move the claws 31 radially outwardly of the post. In Figs. 13-15 the piston (25<SP>1</SP>) has a cam face (28<SP>1</SP>) co-operating with four cam-shaped followers (33) normally urged by torsion springs (34) outwardly of the post (B<SP>1</SP>). Claws (35) of the followers (33) engage a shoulder (32a) of the post when the piston moves under the action of oil entering the chamber (10<SP>1</SP>). In the machine of Fig. 19 only one platen 44 moves, and clamping units 71, 72 mounted on a fixed support 39 act on posts 67, 68 to seal the mould 44a, 48a by a pushing action. A pump 59 supplies pressure fluid to a mouldclosing cylinder 42, a cylinder 50 for operating an injection ram 49, and the clamping units 71, 72. An adjustable trip 53 carried by the ram operates a switch 54 which starts a timer 55 controlling a multi-way valve 57. Switch 54 also controls a solenoid 66 which opens a valve 64 to control the supply of fluid through cylinder 42 to the clamping units 71, 72.