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US 4,070,021 AGranted
Composite high strength to weight structure having shell and sleeved core
AssigneeFansteel Inc.
InventorsAndrew W. Cecka, Pol Dano, Paul G. Pawling
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AssigneeFansteel Inc.
InventorsAndrew W. Cecka, Pol Dano, Paul G. Pawling
Estimating the term…
A novel structural member, such as a tennis racket frame, having an unusually high strength to weight ratio is provided comprising an expanded foamed plastic core integrally bonded to a shell comprising at least one layer of resin-coated unidirectionally oriented graphite fibers, the shell completely encasing the core at any transverse cross section of the structural member, with a seamless sleeve made of a thin, flexible cellulosic film between the core and the shell. The structural member is prepared by arranging within a mold cavity an outer shell comprising at least one sheet of resin-coated unidirectionally oriented graphite fibers and a core comprising a foamable resin composition while the core is maintained within a seamless sleeve made of a thin, flexible cellulosic film, sealing the mold cavity and activating the foamable resin composition to cause expansion and generate pressure within the mold cavity and thereby provide intimate bonding of the core to the shell.
A structural member of high strength to weight ratio comprising a core of an expanded porous resinous material integrally bonded to a shell comprising at least one layer of resin-coated unidirectionally oriented graphite fibers, said shell completely encasing said core at any cross section transverse to the length of said member with a seamless sleeve made of a thin, flexible cellulosic film between said core and said shell.
In a tennis racket frame having a handle and an ellipsoid head attached to one end of said handle and a grip element at the opposite end of said handle, an improved construction wherein said frame comprises a structural member of high strength to weight ratio comprising a core of an expanded porous resinous material integrally bonded to a shell comprising at least one layer of resin-coated unidirectionally oriented graphite fibers, said shell completely encasing said core at any cross section transverse to the length of said member with a seamless sleeve made of a thin, flexible cellulosic film between said core and said shell.
In a tennis racket frame having a handle and an ellipsoid head attached to one end of said handle and a grip element at the opposite end of said handle, an improved construction wherein said frame comprises a structural member of high stength to weight ratio comprising a core of an expanded porous resinous material occupying from about 20 to about 60 pounds per cubic foot, said core being integrally bonded to a shell comprising a plurality of layers of resin-coated unidirectionally oriented graphite fibers with a seamless sleeve made of a thin, flexible cellulosic film between said core and said shell, at least one of said graphite fiber layers having its fibers oriented in a direction different from the direction of orientation of the fibers in at least one other of said layers, each end of said member being at the grip end of said handle, said member extending from one of its ends at the grip end of said handle up one side of said handle, around a major portion of the head of said frame and down the other side of said handle to the opposite end of said member at the grip end of said handle.
Dependencies are inferred from the claim text.