Abstract: A golf ball includes a hollow core formed of a material having a specific gravity of 1.05-1.25 and having a concentric spherical inner cavity, a cover formed on the outer surface of the hollow core, and a resin layer applied onto the inner surface of the hollow core and having a thickness of 1-3 mm. The resin layer is preferably formed of a material having an Izod impact resistance of 50 J/m or greater. The hollow core preferably has a wall thickness of 7-11 mm. The Shore D hardness of the resin layer is preferably greater than that of the hollow core by at least 10. The golf ball does not suffer breakage of the hollow core due to an impact acting on the golf ball upon being hit, and has proper degrees of hardness and resilience in order to increase travel distance.

Abstract: A softball has a high end synthetic leather stitched cover formed from a low density non-woven fiber mat impregnated with polyurethane. The softball, which can be formed to meet association specifications, has a circumference of 11 or 12 inches and a cover to core weight ratio significantly less than 0.1, typically in the range of 0.08-0.16, while meeting durability requirements. The cover preferably has a thickness of 0.045-0.065 inches. Because a greater weight concentration is in the core of the ball, the ball has improved playability characteristics over conventional balls having heavier synthetic leather covers, while exhibiting a sound comparable to that of a leather covered softball when struck with a bat.

Abstract: Novel golf clubs (10, 50) and associated methodology optimally minimize air resistance during swinging motion of the golf club (10). A first golf club (10) comprises a head (12) a handle (18) and a shaft (22) connecting the head (12) with the handle (18). A rib (24) protrudes outwardly from the shaft (22) and runs longitudinally along the shaft (22) in a spiral configuration. The spiral configuration has a pitch which decreases from the head (12) to the handle (18). The spiraling configuration of the rib (24) minimizes vortices and drag generated when the golf club (10) is in motion to thereby decrease air resistance to the golf club (10).

Abstract: A novel golf club (10) and associated methodology optimally minimize air resistance during swinging motion of the golf club (10). The golf club (10) comprises a head (12) for striking a golf ball, a handle (18) for swinging the golf club (10) and a shaft (22) connecting the head (12) with the handle (18). A rib (24) protrudes outwardly from the shaft (22) and runs longitudinally along the shaft (22) in a spiral configuration. The spiral configuration has a pitch which decreases from the head (12) to the handle (18). The spiraling configuration of the rib (24) minimizes vortices and drag generated when the golf club (10) is in motion to thereby decrease air resistance to the golf club (10).

Abstract: A string for sports application, in particular for tennis, badminton, racquetball and squash racquets or the like comprises a center core and at least one ribbon-like wrap made of a highly abrasion resistant material which exhibits a higher melting point and at least one of a higher dynamic stiffness and a lower static stiffness than the core material. A preferred wrap material meeting the above criteria is poly(m-phenylene isophthalamide). The wrap should cover at least 25%, and preferably at least 50% of the center core's outer surface to reduce notching. Due to the reduced notching, superior combined properties of durability, playability and minimal loss of string tension are achieved.

Abstract: A bladder for a game ball is formed from a composite film which is made from a mixture of polyurethane and polyvinylchloride.

Abstract: This invention discloses a novel head of a golf club, especially of the type called "wood". The head includes a foamed core means therein which is firm with a light weight. The head also includes a face directly attached to the core means. The core means with the face is molded over with a shell. The inclusion of the core enables the head to be big with a light weight. The direct attachment of the face to the core means enables avoidance of deviation of the face relative to the core means over long use.

Abstract: A telescopic cue for billiards, pool, snooker and the like includes telescopically engaged central and butt sections permitting infinite adjustment of cue length between two end positions and a lock for securing the central and butt sections by frictional engagement at any selected cue length. The frictional engagement is provided by a member on one of the butt and central sections arranged for radial expansion or contraction to engage frictionally the other of the butt and central sections to prevent relative axial movement of the butt and central sections. The member may comprise a collet disposed between two relatively movable abutments which are urged towards one another on relative rotation of the butt and central sections or two parts of the same section to expand or contract the member to provide the aforesaid frictional engagement.

Abstract: A fastener comprises a filament having two opposing heads. The heads have two ends defining non-parallel planes, forming acute angles which share a common ray. The fastener is installed by being driven through two needles having slotted bores.

Abstract: Improved tennis racket in which an inverted chevron shaped yoke is provided having downward sloping side portions which match the curvature of the arcuate top portion of the racket head to provide vertical strings extending between the yoke and arcuate top portion which are of the same length. The equal length of vertical strings provide uniform elastic response to ball impact. The particular design of the chevron provides added structural strength to the neck of the racket. An improved racket made from a polycrystalline metal oxide fiber and resin matrix is also disclosed. In addition, an improved string protection system involving elastomer inserts which are molded into the head portion of composite material rackets is described.

Abstract: The golf club head comprises a shaped core body of material selected from synthetic and natural rubber and an outer shell closely surrounding substantially the entire surface of the core body of polymeric thermoplastic material selected from the group of polycarbonate, polyamide and polybutylene-terephthalate. According to a preferred embodiment, the golf club head further comprises a center core body embedded within the core body and consisting of closed envelope completely filled with liquid.

Abstract: A composite racquetball racquet comprises a molded synthetic plastic frame member on which is adhesively bonded a generally U-shaped channel and a synthetic plastic bumper strip is adhesively bonded over the channel outer periphery at the outer head portion of the frame. Mechanical interlock formations are provided between the plastic frame member and the metal channel side walls.

Abstract: A skip rope for exercise and fitness conditioning includes a length of polypropylene rope threaded through two handle members disposed at opposite ends of the length of rope. After the rope is threaded through each handle member, the free ends of the rope are knotted to prevent it from pulling back through the two handles. Each handle is constructed of a tubular section of polyvinylchloride which has nylon end plugs press fit into the open ends of the tube. The outside diameter surface of each end plug coincides with the outside diameter surface of the polyvinylchloride tubing and each end plug includes a rope-receiving clearance aperture just slightly larger than the outside diameter of the rope. The material combination of nylon for the end plug and polypropylene for the rope provides a type of self-lubricating interface which enables the rope to turn and twist completely independent of the handle.

Abstract: In a slingshot which includes a handle-supported yoke including a pair of laterally spaced rods to which missile-projecting elastic bands are attached, the improvement comprising a pair of flexible tube segments sleeved over the elastic bands in a zone of attachment of the bands to the rods. The elastic sleeves constitute bend resisting elements and obviate sharp reverse folding of the elastic bands which normally occurs upon recoil of the bands following distension and release of the stretched elastic bands in projecting a projectile.

Abstract: Prepolymerized resins are applied to wooden articles to coat them and impart a tough and abrasive resistant surface which protects the articles from deterioration and delamination due to shock, impact and abrasive forces. The resins are applied by contacting the articles with a prepolymerized resin which has been dissolved in a readily vaporizable solvent to form a resin solution, coating the article with the resin solution, vaporizing the solvent from the resin coating and drying the resin coating. The coated articles find particular utility in high shock and impact uses such as hockey stick blades.

Abstract: A target made of interchangeable sections each comprising a multiplicity of membranes or plies of penetrable, elastomeric or resistant, tear resistant sheet resin material, the membranes being separated by intervening layers of porous or low density, resilient material such as foam resin material. Membranes are disclosed having opposite surfaces with different coefficients of friction.

Abstract: A laminated material suitable for use in inflatable playballs comprises a first layer of thermoplastic synthetic resin and a second layer. The second layer is formed of two thermoplastic resin materials, one having a tensile strength greater than the material of the first layer and forming a lattice structure and the other filling the interstices of the lattice structure, the filling material being exposed at one surface of the second layer and bonded at that surface to the first layer.

Abstract: A target made of interchangeable sections each comprising a multiplicity of membranes or plies of penetrable, elastomeric or resilient, tear resistant sheet resin material, the membranes being separated by intervening layers of porous or low density, resilient material such as foam resin material.

Abstract: Preferably two bow string silencers, each comprising an elongated rectangular strip of flat flexible, resilient material having a multi-point contact with a bow string and including a multiplicity of discrete energy dissipating members formed along the opposite elongated sides are attached to each bow string. The silencers have very small volume and weight and are constructed from high strength material so as not to interfere with the throw of the arrow, can be readily adjustable along the bow string to locate for maximum energy attenuation and will resist being torn off by repeated throwing of arrows.

Abstract: Various embodiments of a handheld tennis practice device are disclosed. The device generally comprises a flexible L-shaped rod or tube having a ball affixed at one or both ends thereof. Means which enable the user to securely grip the device are also disclosed, as well as improved means for securing the ball to the end of the rod or tube. To be more specific, a first gripping member or handle is disposed at the outer end of one leg of the L-shaped device and a knurled region for gripping by a user is disposed on the other leg of the L-shaped device in the vicinity of the juncture of the legs of the device. The device is designed to enable the user to practice various strokes involved in racquet sports. It is particularly suited for the practice of tennis strokes.

Abstract: A hockey stick is made as a unitary, injection molded product from foamed nylon mixed with glass fibre. The use of foamed nylon results in a relatively lense shell on surface and a core having reduced density. There are no cavities in the stick such as in known hockey sticks or the like made of plastic material. The stick maintains its shape after molding due to a relatively low stress caused by molding pressure which is low in comparison with that required in the production of known plastic hockey sticks. The stick is generally identical to a regular wooden stick from the standpoint of weight and that of weight distribution. An embodiment of the stick with aluminum reinforcement of its blade portion is also disclosed.

Abstract: A molded, plastic tennis racket frame is described which is constructed of a combination of glass fiber reinforcement and carbon fiber reinforcement to provide a low specific gravity composite when incorporated in resins which are reinforced by these materials and to permit construction of a tennis racket having a general shape of conventional wooden rackets. The tennis racket is constructed as a unitary piece utilizing foamed resins reinforced with the glass fibers and carbon fibers. Specific weight percentages of glass fibers and carbon fibers are designated for maximum strength, flexibility and good playing characteristics.

Abstract: A nunchaku having two spaced apart rod-like elements or handle members, each element being formed of a plastic insert molded in a body portion which forms the balance of the element. The plastic insert, which is formed on nylon 6/6, has two spaced apart generally parallel apertures extending from one exterior sidewall of the element to the other exterior sidewall, the insert being disposed in one end of the element. The balance of the element is formed of high density polypropylene which is molded about the insert, the body portion having better impact resistance than the insert, and the insert, which receives a cord to secure one element of the nunchaku to another element of the nunchaku, having better wear resistance and greater strength than the high density polypropylene.

Abstract: Improved tennis racket in which an inverted chevron shaped yoke is provided having downward sloping side portions which match the curvature of the arcuate top portion of the racket head to provide vertical strings extending between the yoke and arcuate top portion which are of the same length. The equal length of vertical strings provide uniform elastic response to ball impact. The particular design of the chevron provides added structural strength to the neck of the racket. An improved racket made from a polycrystalline metal oxide fiber and resin matrix is also disclosed. In addition, an improved string protection system involving elastomer inserts which are molded into the head portion of composite material rackets is described.