GB1201063A - Method and apparatus for the production of multi-layer building boards - Google Patents

Abstract

1,201,063. Laminated building board; circular saws. H. PRIGNITZ, [trading as HAPRILEICHTBAUPLATTENWERK]. 17 Aug., 1967 [22 Aug., 1966; 23 Nov., 1966], No 37881/67. Headings B5L and B5N. In a method of producing a multi-layer building board having a foamed plastics material layer e.g. of polyurethane bonded to a layer of strong facing material, a length of strong facing material 13, Fig. 3, is carried on a moving conveyer belt 10 under a foaming head 15, constituents of the plastics material to be foamed are fed in liquid state from a nozzle of the foaming head onto the upper face of the material 13 to form a layer 12 thereon, a fabric web 16 is run substantially parallel to and above the material 13 on the belt 10 into the material 12 as the latter is formed, and foamed plastics is allowed to harden and bond to the material 13 and web 16 to form a composite multi-layer structure from which a building board of the required length is severed transversely to the direction of movement of the structure, the fabric web 16 serving to compensate for shrinkage stresses set up on hardening of the foamed plastics. In one apparatus Fig. 3 for performing the method the foam constituents are applied from the head 15 onto a strong lining 13 of bitumen paper carried by the conveyer 10, and foaming occurs between the lining 13 and an upper moulding belt 14 which may be shaped to form protuberances on the foamed plastics and may be covered by a plastics foil. The fabric web 16 is also fed into the plastics material as it foams to prevent the finished board bending due to differential shrinkage of the plastics foam as it sets. If the fabric web 16, which may be of jute, cotton, or plastics material, is of narrow mesh, the foam materials may be applied through it to the lining 13. In a further process, Figs. 6 and 8, for producing building boards in which the lining material projects at at least one edge of the foamed plastics body, cut lining pieces 30, 30<SP>1</SP>, 30<SP>11</SP> are arranged in overlapping relation on a belt 25 using a gauge 31, and foam plastics constituents applied thereto from a head 29 are allowed to foam between upper and lower belts 26, 25 and side rails 27. The rails 27 are spaced above the belt 25 to allow the linings to project at the edges of the plastics body. The edges of the foamed and set plastics are trimmed by saws 39, one of which is positioned by feeler roller 37 so as not to cut through the lining pieces, and the plastics foam is cut transversely to form individual boards by a saw 45 which moves transversely of the boards on a carriage 43 and is moved along with the boards on a carriage 40. A hooked lever on the carriage 40 locates the saw relative to the overlapping edges of the lining pieces and the saw is arranged not to cut through such pieces. In an alternative process the lining pieces are replaced by a continuous web of lining material, and the carriage 40 is attached to the foamed material by a clamp 36 during cutting by saw 45.