Patent EA-004153-B1 (EA)
Title: Method of manufacturing moulded articles and installation therefor
Inventor: DU TOIT PIETER WOUTER
IPC: B28B1/24
Filed: 2001-02-14
Abstract: 1. A method of manufacturing a moulded article, the method comprising compounding a mouldable material and a filler in a compounder to provide a supply of mouldable material in which the filler is distributed, mouldable material with the filler distributed therein feeding out of the compounder and along a feed path leading from said compounder to a holding cavity which communicates with the mould cavity of a mould, and urging the filled mouldable material out of the holding cavity and into the mould cavity by advancing a piston in a forward stroke from a retracted position to a forward position, the face of said piston which is leading during said forward stroke becoming part of the bounding wall of said mould cavity upon it reaching the limit of said forward stroke. 2. A method as claimed in claim 1 and comprising closing the mould before urging mouldable material into said mould cavity from the holding cavity. 3. A method as claimed in claim 1 and comprising closing the mould after flow of mouldable material into the mould cavity from the holding cavity has commenced. 4. A method as claimed in claim 1, wherein said filler comprises reinforcing fibres. 5. A method as claimed in claim 4, wherein said fibres are natural fibres. 6. A method as claimed in claim 1, wherein said filler is in the form of particulate material. 7. A method as claimed in claim 6, and including the step of compounding wood or chips of another material with the mouldable material. 8. A method as claimed in claim 1, wherein said mouldable material and filler are mixed by feeding them to a barrel which has therein a pair of screws. 9. A method as claimed in claim 8 and including the step of feeding a roving to said barrel. 10.A method as claimed in claim 1, wherein said mouldable material is a synthetic plastics material and the method includes the steps of melting the material in the compounder, feeding the molten mouldable material with filler dispersed therein to a heated vessel which maintains the mouldable material in its molten condition, and feeding molten mouldable material with filler dispersed therein from said vessel to said holding cavity. 11. A method as claimed in claim 10 and including the step of feeding molten mouldable material with filler dispersed therein from said vessel to at least two holding cavities sequentially. 12. A method as claimed in claim 1 and including the step of displacing said holding cavity from a first position which the holding cavity occupies whilst mouldable material with filler dispersed therein is fed into it to a second position in which it is in communication with said mould cavity, said piston urging said mouldable material with filler dispersed therein out of the holding cavity whilst said holding cavity is in said second position. 13. A method as claimed in claim 1 and including the step of feeding a measured charge of mouldable material with filler dispersed therein to said holding cavity between said piston and the mould cavity and thereafter displacing the piston in its forward stroke. 14. A method as claimed in claim 1 and including the step of placing a layer in the mould cavity before urging the mouldable material into the mould cavity onto the back of the layer thereby to form an article with in-mould decoration. 15. A method as claimed in claim 1, wherein said mouldable material is a clay compounded with water. 16. A method as claimed in claim 1, wherein said mouldable material is a metallic powder compounded with a binder. 17. An installation for manufacturing a moulded article, the installation comprising a compounder which provides a supply of mouldable material with filler dispersed therein, a holding cavity, means defining a flow path from the compounder to the holding cavity along which path mouldable material with filler dispersed therein flows to the holding cavity, a mould having an open condition and a closed condition, the mould defining a mould cavity, an opening which places said holding cavity in communication with said mould cavity, and a piston which has a front face and is displaceable in a forward stroke from a retracted position to a forward position, said piston displacing the mouldable material with filler dispersed therein out of said holding cavity and into said mould cavity through said opening as it performs said forward stroke, the front face of the piston when it is in said forward position forming part of the bounding wall of said mould cavity. 18. An installation as claimed in claim 17, wherein said compounder comprises a barrel and a pair of parallel screws in the barrel for kneading and mixing the mouldable material and filler. 19. An installation as claimed in claim 17, and including a heated vessel in said flow path for receiving molten mouldable material with filler dispersed therein from the compounder and maintaining it in a molten state. 20. An installation as claimed in claim 17, and including at least two holding cavities and means for feeding molten mouldable material with filler dispersed therein from said vessel to said holding cavities in sequence. 21. An installation as claimed in claim 19, and including means for displacing said holding cavity between a first position that it occupies whilst being filled with mouldable material with filler dispersed therein and a second position in which it communicates with said mould cavity. 22. An installation as claimed in claim 17, wherein said holding cavity is constituted by part of a barrel in which said piston reciprocates, said part being between said opening and said piston. 23. An installation as claimed in 22, and including a valve which can be opened and closed to control communication between said holding cavity and said mould cavity, said holding cavity being filled whilst the valve is closed. 24. An installation as claimed in claim 22 and including means for delivering a measured quantity of mouldable material with filler dispersed therein to said holding cavity.