Patent GB-676412-A (GB)
Title: Automatically operating hydraulic press for the moulding of thermosetting plastics
IPC: B29C43/00
Filed: 1948-01-20
Abstract: 676,412. Compression moulding machines. MENZEL, E. Jan. 20, 1948, No. 1685/48. Class 87(ii) A press for moulding hollow thimble-like articles from thermosetting plastic material has a mould member 6, Fig. 4, provided with cavities open at both ends, which mould is adapted to move forwardly, so that one end of each cavity is engaged by a core 57 carried by a cross member 5, and then backwardly after moulding to leave the article held between the reciprocating pressure piston 9 and core. Fig. 3 shows a combination of two adjacent pairs of parallel presses arranged back to back, but the presses may be disposed vertically. The press uprights are interconnected by columns 3 which extend through bearing blocks 4 and guide a member 7, Figs. 2, 4, which itself forms a guide for a headpiece 8 provided with adjustable screw-threaded rods 16 supporting pressing pistons 9. The rod 9' of the piece 8 is moved by pressure in a cylinder 11, and two other cylinders 12 move rods 14 connected to the member 7 which is guided by sleeves 15. The mould 6 has heating ducts 19, is detachably mounted on the member 7, and carries a guiding member 20 for the pistons 9 which are adapted to move into the lined bores 17. A hopper 24 is slidably mounted on a fixed table 23 and moves in opposition to the movement of the mould. The plate 25 of the table has apertures 26 which for charging the material via tubes 22, 21 to the mould are aligned with the tubes 22 in the plate 28, which latter plate is urged towards the plate 25 by springs 27 and moves with the mould 6. Formed in the lower face of the table 23 are slideways, Fig. 5, (not shown) in which bars 30, displaceably mounted therein by screws 32, are provided with openings 31 controlling the size of the apertures 26. In operation, the mould with the pistons 9 moves to the right, and the hopper 24 to the left of the apertures 26 until the Fig. 4 position is reached, in which position the bores 17 are closed by the cores 57. A quantity of powder is then fed into apertures 26 anddrops through tubes 22, 21 to the bores in front of pistons 9 which are then moved further to the right to compress the material. The mould 6 is then withdrawn by movement of the member 7 and the moulded articles left held between the pistons and cores, which cores then move away from the pistons 9 allowing the articles to be removed mechanically or by hand. Provided the articles consist of electrially insulating material the machine is prevented from starting upon a new moulding cycle unless all the articles are first removed from the cores. Each member 5 is provided with slip rings 38, Fig. 2, co-operating with stationary brushes (not shown) which interrupt an electrical' control circuit if an article still remains on one of the cores. When the moulded parts are screw threaded the member 5 is rotated step by step by an automatically operated electric motor 35<SP>1</SP>, Fig. 1, (not shown). The moulded articles are then brought in front of a box 39 which is reciprocated in unison with the completion of a moulding cycle by levers 42, 43 from the member 7, so that box spanners 46, Fig. 6, (not shown) which are rotatably mounted in the box, may engage and remove the articles. Specification 674,836 is referred to.