Patent GB-209179-A (GB)
Title: Improvements in apparatus for the manufacture of composition building sheets or slabs
IPC: B28B1/52
Filed: 1922-10-04
Abstract: 209,179. Harrison, J. A., and Waschatz, O. A. Oct. 4, 1922. Endless-chain machines; rolling-machines; tamping-machines; delivery; feeding; moulds; cleaning apparatus; strickles.-A machine for making composition slabs or sheets consisting of a layer of fibrous material embedded between two layers of plaster comprises separate mould tables which are successively passed into the machine, units for distributing by a splashing action in one direction a layer of plaster, levelling and tamping appliances, means for delivering a layer of teased fibres, and a second set of units distributing by a splashing action in a direction opposite to the first a second layer of plaster, means being also provided for automatically elevating the mould tables to a drying-chamber. The mould tables 3, Fig. 1, are propelled along guides 2 by lugs 7 on endless chains 6. Dry plaster contained in a hopper 30 fitted with stirrers 31 is conveyed by a charger 32 to troughs 43 and is delivered by screws to shoots 50 leading to mixing buckets 33, the material being broken up by oscillating grids 49. Water is supplied to each bucket from a tank 69 through a pipe 76 fitted with a cam-controlled valve, and air for agitating the mixture is supplied through a pipe 78 controlled by a valve 79 operated by a cam 81 and lever 80. Each bucket is supported by a table 66 rotated by gearing 68, and is trunnioned on a yoke 65 which is raised and lowered through a screw 94 driven by a gear 98 engaging drive and reverse gears 99 controlled by a timing-cam 100. Lifting of the yoke 65 raises the bucket 33 from the table 66 and through a rod 108, lever 105 and rod 117<2> turns an eccentric to move a friction disc 104 into engagement with a driver 103 winding up a chain 101 attached to the bucket and tilting the latter to discharge its contents on to a trough 118. Upon lowering the yoke 65, the lever 105 operates through a disc 109 to release detent mechanism, freeing the chain 101 and permitting the bucket to return. The troughs 118 lead to a distributing tub 119 fitted with agitators 123 and air jets 138 which supplies the material to a pair of centrifugal splashers 121 inclined as shown. Each splasher comprises a cover plate 129, Fig. 18, furnished with a central aperture 130, and is furnished with a series of arched vanes 135 and bottom openings 136. After leaving the first plaster distributing unit, the moulds pass beneath a curved scraper 144. Fig. 22, comprising a pair of flat metal bars 144, between which short lengths of rubber 146 are secured by bolts 145, the bars being adjustably supported at 149. The moulds next pass beneath a vibratory element 150, Fig. 2, spring-supported and camoperated; and then beneath a fibre-distributor 167 fed by a suitable teasing-device. The moulds then pass to the second plaster distributing unit, Fig. 5, which is similar in construction to that shown in Fig. 1, but is reversely disposed, afterwards passing beneath a leveling-roller 169 reciprocated longitudinally of the machine, and a finishing-roller 179a reciprocated transversely of the machine. Between the rollers 169, 179<a> are scrapers 158 for cleaning the edges of the moulds. The moulds are elevated to a drying-floor by a pair of chains 212, Fig. 31, furnished with dogs 214 to engage the moulds and co-operating with arms 215. Similar mechanism 196, 204, is employed to lower the empty moulds on to the chains 6, Fig. 1. The mould tables 3 are each built up of boards 8, Fig. 28, secured by staggered dowels 9, united by end rails 10 and equipped with metal wearing-strips 11. A sheet of zinc 12 forming the upper surface of the table is secured by bolts 13. The thickness of the slab is gauged by a bead of wood 19, and escape of material between the moulds is prevented by abutment-strips 19<a> of rubber.