Structural member having a high strength to weight ratio and method of making same

• US 4,399,992 A
• Filed: 03/10/1980
• Issued: 08/23/1983
• Est. Priority Date: 03/10/1980
• Status: Expired due to Term

• Current Assignee: Spalding Sports Worldwide, Inc. (Berkshire Hathaway Incorporated)
• Original Assignee: Questor Corp.
• Inventors: Molitor, Robert P.
• Primary Examiner(s): Pinkham, Richard C.
• Assistant Examiner(s): Schneider, Matthew
• Application Number:
  US06/128,543
• Time in Patent Office: 1,261 Days
• Field of Search: 273/73 R, 273/73 C, 273/73 F, 273/DIG. 1-DIG. 8, 273/DIG. 23, 273/82 R, 428/313.3, 428/313.5, 428/313.9, 428/71, 428/76, 521/122, 521/135, 521/137
• US Class Current: 473/536
• CPC Class Codes: A63B 2049/0211 with variable thickness of the head in a direction perpendicular to the string plane
• CPC Class Codes: A63B 2209/023 Long, oriented fibres, e.g. wound filaments, woven fabrics, mats
• CPC Class Codes: A63B 49/10 made of non-metallic materials, other than wood
• CPC Class Codes: A63B 60/00 Details or accessories of golf clubs, bats, rackets or the like
• CPC Class Codes: A63B 60/54 with means for damping vibrations
• CPC Class Codes: B29C 70/025 with particular filler
• CPC Class Codes: B29C 70/865 completely encapsulated
• CPC Class Codes: B29K 2105/04 cellular or porous
• CPC Class Codes: B29K 2105/0845 Woven fabrics
• CPC Class Codes: B29K 2105/165 Hollow fillers, e.g. microballoons or expanded particles
• CPC Class Codes: B29K 2277/10 Aromatic polyamides [Polyaramides] or derivatives thereof
• CPC Class Codes: B29K 2307/00 Use of elements other than metals as reinforcement
• CPC Class Codes: B29K 2307/02 Boron
• CPC Class Codes: B29K 2309/08 Glass
• CPC Class Codes: B29L 2031/5245 Rackets
• CPC Class Codes: Y10S 273/07 Glass fiber
• CPC Class Codes: Y10S 273/08 Urethane
• CPC Class Codes: Y10S 273/23 High modulus filaments

Abstract

A novel structural member, such as a tennis racket, and the method for making same, provides a high strength to weight ratio. The structural member of this invention consists of a fiberglass shell which surrounds a syntactic foam core. The fiberglass shell may be further selectively reinforced with a ribbon which is formed from a high strength fiber such as boron fibers, graphite fibers, aramid fibers, etc. Because the structure of this invention incorporates a high strength to weight ratio it can be utilized in the manufacture of rackets of conventional and radical design.

This invention relates to a structural member consisting of a tennis racket having a high strength to weight ratio.

Claims

1. In a racket frame having a head, throat and handle, an improved construction wherein said frame comprises

a core consisting of a mixture of syntactic foam and a blowable non-syntactic foam;

a fiberglass outer shell bonded to and substantially covering said core; and

the racket frame further comprising high strength fiber material comprising a ribbon of graphite material woven together by aramid fibers located about at least a portion of said racket frame.

2. The racket frame of claim 1 wherein said high strength fiber material is adjacent both faces of the racket frame.

3. The racket frame of claim 1 wherein said ribbon has a width of between 3/8 inch and 1/2 inch.

4. The racket of claim 1 wherein said ribbon has a width of 3/8 inches.