GB1307305A - Tennis squash or badminton racket frame - Google Patents

Abstract

1307305 Laminated racket AMF INC 21 May 1970 [1 Aug 1969 16 Feb 1970] 24721/70 Heading A6D A racket frame comprises a flat unitary core 20 of lightweight plastics foam material bounded along the inner and outer peripheral edges by a pair of reinforcing webs 25, 24 of plastics material and sandwiched between a pair of unitary flat metal, e.g. Al, plates 26, 28 on the other edges, the webs and plates being thin relative to the core and being bonded to the core to form a frame of rectangular crosssection, a hand grip 34 being fitted over the butt end of the frame, and a triangular cut-out 16 being formed in the throat portion 12 through the plates and core. As described the core comprises a high compressive strength resin, e.g. epoxy, filled with microbubbles of glass or phenolic material, and may be reinforced by loose chopped or milled fibres. Alternatively a urethane foam may be used. The webs may comprise clothbacked polyethylene or other material having a compressive strength of approximately 4,500 to 20,000 p.s.i. and a tensile modulus less than approximately 1,000,000 p.s.i. Metals other than aluminium may be used to form plates 26, 28 provided they have a minimum yield strength of 50,000 p.s.i. and a tensile modulus of at least 1,000,000 p.s.i. Plates 26, 28 may be reinforced by partial or full plates with or without energy absorbing layers, e.g. visco elastic rubber, between the plates. Layers of fibre glass-reinforced plastics may be interposed between the core and plates 26, 28.