GB524743A - Improvements in or relating to molding machines - Google Patents

Abstract

524,743. Rotary-mould-table machines; mechanical presses. ARMSTRONG CORK CO. Feb. 6, 1939, No. 3844. Convention date, May 27, 1938. [Class 87 (ii)] A moulding machine comprises a series of pairs of co-operating mould members 6, 7 mounted on a rotary carrier 4, one of each pair, such as the plungers 6, being loaded by fluid pressure from a common source, and the other mould members 7 being adapted to move and displace the members 6 without increasing the fluid pressure. The rotary carrier 4 is provided with a chamber 29 for pressure liquid with passages 37 extending therefrom to cylinders 22 wherein work pistons 21 carrying the plungers 6. The liquid is maintained under pressure by a piston 30 loaded with weights 31 adapted to move on guides 32, 33. The volume of liquid is maintained by a pump 40 through a valve 44, the pump being operated by a motor through a switch 46 controlled by the weights 31. The pistons 21 are arranged to have compensating up and down movements such that the total volume of the cylinders 22 is maintained substantially constant. The pistons 21 normally abut against ledges on packing glands 25, but are raised when pressure is exerted by the members 7. Plungers 8 carrying the mould members 7 are mounted to slide in the carrier 4 are and operated by toggle mechanism comprising a bell-crank 12 the free arm whereof carries a roller 18 engaging a cam surface 20. The toggle is connected to sliding blocks 10 wherein the plungers 8 are adjustably screwed. The cam is shaped to move the members 7 to apply pressure and may be further shaped to effect temporary retraction of the members 7 to allow air or gases to escape. The cam may be provided with a shroud 54 to prevent rollers leaving the cam, particularly due to adhesion between the articles and the members 7 at separation. The carrier 4 is rotated by a motor 47 through gearing 48. The motor may also serve to drive in synchronism a device 51 for making pre-forms which are fed to the moulds by a shoot 52. Alternatively, powdered or plastic material may be fed direct to the moulds. The members 6, 7 may be provided with electric heaters, current being supplied through slip rings 64, or a pair of annular heaters encircling the carrier may be provided. When internallyscrewed stoppers or other articles are moulded, they may be removed from the plungers 6 by unscrewing by means of a rubber or other friction wheel adapted to contact with the article and rotated by an electric motor.