GB562961A - Improvements in or relating to the production of building members from plaster board - Google Patents

Abstract

562,961. Moulding plaster board. RUSSELL, E. D. B. Dec. 2, 1942, No. 17140. [Class 87 (i)] [Also in Group V] Plaster board consisting of plaster enclosed within two covering plies of deformable material, e.g. paper, is moulded into channel, box or other sections before the plaster has set. Fig. 2 shows apparatus for producing a simple U-shaped channel. As the plaster board 11 advances to the left from the forming rolls (not shown) on an endless belt 12, stationary folders 18 turn the side portions of the board through 90 degrees. The portions are pressed against a stationary rectangular former 19 by travelling belts 23 until the plaster has set. To produce sharp corners on the moulding, the lower ply of the board is scored before passing between the forming rolls. The marginal excess of the upper (inner) ply is glued to the lower ply. Fig. 4 shows modified folders 18 for forming a box-section; in this case, the surplus on one side of the upper ply is cut off by a stationary knife and a roller applies glue to the surplus 15 on the other side, the surplus 15 being pressed against the inside of the moulding .by the core 19 on the inside and a horizontal belt on the outside. A strip of paper 17 may be glued to the putside of the joint. A channel section having thickened edges 29, as shown in Fig. 6, may be made in two stages-first, forming the thickened edges between a lower ordinary roll and an upper profiled roll, and-second, turning up the edges of the resulting sheet around a former 30.