GB827611A - Improvements in and relating to the production of building boards - Google Patents

Abstract

827,611. Severing building boards. IMPERIAL CHEMICAL INDUSTRIES Ltd. June 14, 1957 [June 15, 1956], No. 18547/56. Class 87(2). Building boards, especially gypsum plaster boards, are subjected preferably while in a wet state to a treatment such as perforating or scoring which produces zones of weakness; fed in the dry state in the direction of their length to a driven band conveyer 1 comprising one inclined intermediate and two horizontal end lengths of band 1<SP>11</SP>, 1 1 and 1<SP>111</SP> respectively through a feed roll 7 cooperating with length 11 whereby the bottom layer and at least part of the core are severed under the combined effect of the feed roll and the inclined length 111 ; caused to move forward until the weight of the part extending beyond the inclined portion and/or contact with a downwardly moving surface effects severance of the upper layer and any unsevered portion of the core ; and the severed board allowed to fall on the second horizontal length 1<SP>111</SP> of the band which carries it away. The apparatus shown in Fig. 1 comprises three similar band conveyers 1 arranged in parallel on common head and tail shafts 2, 3, idler pulleys 5, 51, 511, 4, 5111, 5<SP>1111</SP> and 6<SP>1</SP> being arranged to provide the short run 111 which is inclined at about 20 to 30 degres to the horizontal. The pulley 4 is adjustable so that it can, when the board being made is unperforated and does not need to be severed, be fixed in a lower position 4<SP>1</SP>, such that the run 111 is then horizontal, the slack of the band being taken up by movement of the shaft 3 or by moving the adjustable roller 5<SP>1</SP> downwards. By adjusting the position of the feed roll 7 the machine can be adapted to permit feeding boards of different thickness and for severing different lengths of board. The downwardly moving surface mentioned above may be provided by an auxiliary band 8 carried on rollers 9, 91, roller 9<SP>1</SP> being driven, for example by the spur gearing 10 which also drives the head shaft 2. In a modified form of apparatus the three continuous unitary bands are each replaced by three separate bands in series, the intermediate one of which is inclined when the machine is being used for severing but can be lowered into a horizontal position when not being so used. This form of apparatus operates in a similar manner to the above.