GB635823A - Improved method of manufacturing composite metal-fibrous structures - Google Patents

Abstract

635,823. Compound sheet materials. KING, E. P. June 1, 1945, No. 8189/44. [Class 140] [Also in Group XXXIII] In forming a laminated structure two preformed structures are first formed by bonding metal sheets to fibrous material with synthetic resin, the two fibrous layers being subsequently bonded together or to an intermediate layer or structure by means of a cold-setting adhesive at normal or slightly elevated temperature. Fig. 1 shows a metal layer 21 attached to a fibrous layer 22. The metal layer may be first roughened mechanically, electrolytically or chemically. Two such preformed sheets may be joined with their metallic layers outwards, with or without the interposition of veneers of wood or strips, 23, of balsa wood (Fig. 4). Alternatively the sheets may be spaced apart with laminated stringers 24 (Fig. 7). The spaces between the stringers are left empty or filled with lightweight material such as expanded rubber. A rib 27 (Fig. 9) may be secured to one of two composite sheets by a rivet 28 before the two sheets are secured together. They may be secured with a further rib between. Fig. 11 shows a method of forming a composite sheet using two metallic sheets 28, 29 with their edges butting at 30. A cross-grain piece of veneer 31 is laid on the join with a strip of metal 32 on top. The fibrous layer 34 is then laid over the whole and all the layers secured together. Alternatively, the fibrous layer 34 may be laid directly on the metal sheets and the pieces 31, 32 on top. Fig. 13 shows a number of separate sheets assembled in an autoclave for forming into a single composite sheet with a single fibrous backing layer. The component parts are laid on a metal platen 36 supported on a channel frame 37. A layer of hessian or wire gauze is laid over the parts which are then covered with a sheet of rubber &c. secured to the edges of the platen. Heat and pressure are then applied and any vapours produced exhausted through holes 38 and 39 in the platen by pipes 40, 41. A curved platen may be used and the Specification describes the manufacture of a double-skinned aeroplane fuselage in this way. The metal and fibrous elements of the inner and outer skins are separately assembled on platens in the form of male and female moulds respectively and bonded with synthetic resin. The two bonded skins, on the two moulds, are then united with cold-setting adhesive. An aeroplane wing (Figs. 16 and 17) is built in two halves and joined by tongues 72, 73. The inner and outer surfaces of each half are formed of metal skins 58, backed by fibrous layers 59 and are spaced by stringers 60. Near the ends of the shear member 61 the space between the layers 59 is filled with laminated strips 62. The shear member 61 is secured to the wing surfaces by plywood angles 63 and the half-ribs 68 and 69 by plywood angles 70, 71. The shear member is of laminated construction, formed in two parts, attached to the two halves of the wing, joined by a tongue 65 or by pairs of angles. Metals quoted as suitable for the purposes of the invention are aluminium, magnesium, copper, zinc, iron, steel or alloys thereof. As fibrous material, wood, fabric paper or glass cloth may be used. The synthetic resin for bonding the metal and fibrous layers may be of the phenol-aldehyde type with or without the addition of aniline-aldehyde or vinyl resin. The cold-setting adhesive may be a catalyzed phenol-formaldehyde or ureaformaldehyde cement. Specification 532,716 is referred to.