Patent GB-1370297-A (GB)
Title: Machine for isostatic moulding
IPC: B30B15/30
Filed: 1971-11-02
Abstract: 1370297 Compressing particulate material OLIN ENERGY SYSTEMS Ltd 2 Nov 1971 [28 Aug 1970] 41661/70 Heading B5A An isostatic moulding machine in which particulate material is compacted within a bag contained in a mould, each mould is conveyed to a station where it is filled with such material, a compaction station where the charge is isostatically compressed and an unloading station where the moulded article is removed. As described, three moulds 16, Fig. 4, are supported in bushes 15 carried by a rotary table 14 indexed about a centre post 10 to pass through the three stations 18, 19 and 20 respectively, Fig. 2. Each mould includes a bag or diaphragm 247, Fig. 7, attached to the mould top by means 248, 249, and a core or mandrel 252, 253 providing a moulding space 245 between the mandrel and the bag. At the filling station, Fig. 4, the mould is located centrally above a plunger 58 which is then raised to insert a probe 59 at the end of the plunger into the mould base; the mould is thereby raised to engage a tube 52 depending from a particulate material supply hopper, and a pin 54 engages a hole 257 in the core. A vacuum is applied to the mould cavity surrounding the bag to draw it against the mould wall by the probe which is connected to a lower pressure source via a passage 60. A lesser vacuum is applied to the mould cavity 245. During mould filling the mould is vibrated by a vertically reciprocated plunger 75 striking an impact button 73 on a ring 72 pivoted at 70. After filling, the plunger 58 is retracted and the mould lowered on to the table 14 which is then indexed to the compacting station, Fig. 7, where a plunger 106 and a piston 120 are raised to urge the filled mould against a plate 102 whereby the diaphragm is forced against a seal 250. Fluid-pressure is applied to the diaphragm through a probe at the upper end of the plunger and via a passage 111; when compaction is complete a vacuum is applied to pull the diaphragm away from the moulding and back to the mould wall. The plunger, piston and mould are then lowered and the mould indexed to the unloading station Fig. 6, where a shaft 204 is lowered by an hydraulic cylinder 201 until its end enters the hole 267 in the mould core; a piston 207 at the shaft end is then lowered by pneumatic pressure supplied through shaft bore 215 and urges catches 213 radially outwardly to engage the hole. The shaft is then raised together with the core and moulded article, the latter being stripped from the core on striking a ring 217 containing air jets 219 which clean the core. The article is received by a platform 229 oscillated about the axis of a shaft 227. The core is then lowered into the mould by the shaft 204 and released. therefrom by raising its piston and releasing the catches; after raising the shaft the mould may return to the filling station. In an alternative apparatus the rotary table is raised and lowered at each station. The mould 16, Fig. 5, comprises a bag 323 within a perforated cylinder 313 resting on a plate 314 held by a ring 315. A piston 324 with a depending bolt 328 is forced upwardly at the compaction station to act on hydraulic fluid filling the space 318 and the volume surrounding the bag. At the compressing station, Fig. 4, the bolt 328 is received by an adapter 338 at the top of a plunger 332 which is raised by an hydraulic cylinder 334 to abut the piston 324 whereupon a piston 344 is urged upwardly to drive the piston 324 and effect compaction. At the unloading station a vertically reciprocable and horizontally oscillatable suction cup picks up the moulded article from the mould and deposits it on a conveyer.