Patent GB-840268-A (GB)
Title: "a process and apparatus for the continuous manufacture of sheet-like articles from a pourable fibrous substance, in particular figured-wood sheets from synthetic wood shavings"
IPC: B27N3/20
Filed: 1957-10-29
Abstract: 840,268. Making sheets from wood-fibrous materials. INTERWOOD A. G. Oct. 29, 1957 [Nov. 2, 1956], No. 33748/57. Class 87(2). [Also in Group XXX] A measured quantity of a fibrous substance e.g. wood shavings, with a binder which may be already in the fibrous substance, is laid on an intermittently-moving conveyer belt, prepressed and pre-cut on the belt, and the resulting slabs transported on pallets by additional conveyer means to a press. The wood shavings may be specially cut and the binder may be urea-formaldehyde glue. Devices 45, 46, 47, 48 deposit a weighed quantity of the substance on a conveyer belt 41. Each such device, e.g. 45, has rotary-vane feeders 49 and a vibrating screen 50 which spreads out the material evenly. Some or all also have subsidiary conveyer belts 84, 85 which ensure even distribution on the belt 41. The belt 41 conveys the layers of material to a press where it is compressed between a table 53 and platen 54, the platen being hydraulically operated, and the fluid pressure controlled by a valve 56. The belt 41 conveys the compressed material from the press and is guided by rollers, as diagrammatically shown, so that there are depressions in its level which allow clearances for circular saws 60, 61 to cut the material lengthwise and widthwise to form slabs. At the end of its run the belt 41 delivers the slabs in succession on to pallets which rest on a second conveyer belt 43, stationary at the time, which follows the belt 41 in the path of the slabs. Empty pallets are transferred from a further conveyer belt to the belt 43 by a lifting device, Fig. 3, whereby a plate 34 is connected through a hose 35 to a vacuum pump 36, and is suspended from a band 39, which is guided over rollers 38 arranged as shown, one driven by a motor 37, so that the plate 34 is raised and lowered, travelling backwards and forwards between the two conveyers. The belt 43 conveys the pallets, carrying the pre-compressed slabs, to a multitier hot presss 68, which is fed by the elevation, in stages, of a tier of shelves 69 on to which the pallets are slid successively. The hydraulic means which raise the shelves 69 are controlled by a valve 72. The overall operation is governed by an electronic device 75. This device starts the motor 42 which drives the belt 41, and starts the motors 51, 52 of the rotary feeders and vibrating screens. The circular saws 60 operate while the belt 41 is in motion. When a pallet has fully received a pre-compressed slab a photo-electric cell 78 actuates the device 75 which stops the motors 42, 51, 52. A solenoid 59 then opens the valve 56 and the pre-compressing press operates ; elso the motors 63, 64 are started and the previous slab (already cut to width) is cut to length. When a pallet has been delivered by the belt 43 to the feeding device 67 it operates a limit switch 81 and stops the belt 43. The lifting device 65 then lowers an empty pallet on to the stationary belt. Meanwhile the devices 45, 46, 47, 48 are replenished and the cycle restarts after a time interval which can be adjusted. A warning signal is given if the replenishment fails. The speed of the motors 51 is controlled, to give layers of uniform thickness, by the effect of the weight of material remaining in the devices 45-48. Feeler switches 79, 78 operate when the feeding device 67 cannot receive the next pallet, so delaying the belt 43 to allow an accumulation thereon. Any waste material is removed at the junction between the conveyers 41, 43 by a suction device, not shown.