Abstract: A sports apparatus with variable directions of stiffness and flexibility, including sports equipment having a body; and a flexure resistance spine that is elongated and is stiffer and less flexible in one direction than in a different direction. The spine is fixed against rotation at two spaced apart locations along the body.

Abstract: An annular or porous insert of predetermined weight is mounted at a predetermined location within a tubular golf shaft, the shaft being of any suitable material including either metal or graphite. The insert is circumferentially uniform and is dimensioned so that it does not of itself have an impact on the swing characteristics of the shaft, other than the swingweight and/or the total weight of the manufactured shaft. In this way the swingweight and/or the total weight of the shaft can be altered without having to change the construction of the shaft. Furthermore the insert is simple to install at any desired location and it does not interfere with the assembly of the finish club, nor does it violate the standards of the USGA.

Abstract: A golf club having a hollow shaft whose flexibility is altered by rotating the club handle. Change in flexibility results from change in tension on a wire coinciding with the shaft longitudinal axis. The wire is attached between a longitudinally movable assembly in the handle and a fixed assembly at the shaft lower end. The movable assembly includes outer and inner tension tuner members, a collar, a clamp and bifurcated collet, and outer and inner twist-prevention housings.

Abstract: A golf club includes an electroactive assembly attached to the club and electrically tuned to capture energy from one or more vibrational modes with high efficiency. More generally, a sports implement includes an electroactive element, such as a piezoceramic sheet attached to the implement, and a circuit attached to the electroactive element. The circuit may be a shunt, or may include processing such as amplification and phase control to apply a driving signal which may compensate for strain sensed in the implement, or may simply alter the stiffness to affect performance. The electroactive element is located in a region of high strain to apply damping, and may include plural subassemblies mounted to capture energy in different planes, or to capture an asymmetric strain distribution while maintaining structural symmetry. In a ski the element captures between about one and five percent of the strain energy of the ski.

Abstract: A vibration damping insert adapted to be positioned within the hollow tubular shaft of a golf club. The insert includes a central rod member sized to fit within the hollow shaft of the club and a plurality of circumferentially spaced fins extending radially outwardly from and substantially coextensive with the rod member, with the fins sized and configured to engage the inner tubular surface of the shaft. The fins form a part of an annular outer body separate from the central rod member and formed of a material having a durometer hardness less than the durometer hardness of the central rod member. The central rod member and annular outer body are preferably formed in a coextrusion process.

Abstract: A golf club includes an electroactive assembly attached to the club and electrically tuned to capture energy from one or more vibrational modes with high efficiency. More generally, a sports implement includes an electroactive element, such as a piezoceramic sheet attached to the implement, and a circuit attached to the electroactive element. The circuit may be a shunt, or may include processing such as amplification and phase control to apply a driving signal which may compensate for strain sensed in the implement, or may simply alter the stiffness to affect performance. The electroactive element is located in a region of high strain to apply damping, and may include plural subassemblies mounted to capture energy in different planes, or to capture an asymmetric strain distribution while maintaining structural symmetry. In a ski the element captures between about one and five percent of the strain energy of the ski.

Abstract: A shock-absorbing device is designed for use in ballgame goods having a tubular rod-shaped body and is composed of a tubular body and a weight. The tubular body is made of a soft elastic material. The weight is disposed in the tubular body such that weight is connected with the tubular body, and that an interstice is located between the outer surface of the weight and the inner wall of the tubular body so as to enable the weight to vibrate in the tubular body. The tubular body of the shock-absorbing device is disposed in the inner wall of the tubular rod-shaped body of the ballgame goods. The tubular body is capable of absorbing shock wave of the ballgame goods. The vibrational motion of the weight is capable of canceling shock wave of the ballgame goods.

Abstract: A set of golf shafts is disclosed. The set comprises a plurality of shafts that decrease in length along the set. Each shaft includes a reverse taper section disposed a distance from the tip section on each shaft. The distance of the reverse taper section varies along a number of shafts as the shaft length decreases.A golf club shaft is disclosed. The shaft includes a tip section, lower section, and an upper section. The tip section connects with a golf club head. The lower section includes a tapered section and a reverse taper section. The tapered section extends from the tip section. The tapered section increases in diameter in a direction away from the tip section. The reverse taper section extends between the tapered section and the upper section. The reverse taper section has a diameter that decreases in a direction away from the tip section. The shaft further includes a resilient plug wedged inside the shaft.

Abstract: A sports apparatus with variable directions of stiffness and flexibility, including sports equipment having a body with an elongated cavity; and a stiffening rod that is elongated and has a longitudinal axis in a direction of elongation of the stiffening rod, the stiffening rod being inserted within the cavity and stiffer in one direction than in a different direction and being more flexible in the different direction than in the one direction, both the one direction and the different direction being directed transverse to the longitudinal axis.

Abstract: A golf club comprising a shaft, having a handle end where grip may be installed and a head end where head may be installed, said shaft is characterized by having a concentric inner member, at least partially covered by the shaft, comprising a handle end, rigidly joined to said handle end of the shaft and the other end extending towards said head end, said inner member is designed to engage the shaft internally at the end extending towards the head end of said shaft at least when said shaft is bent during swing of the golf club.

Abstract: The golf club according to the invention consists, besides a grip and a head, of a compound shaft which has at least an outer shaft defining a hollow portion, a head end, a head end section, a grip end section and a butt end; and an inner shaft partially disposed within the hollow portion of the outer shaft, wherein the inner shaft has a fixed first end region, a second end region, and an intermediate section. During bending of the golf club shaft, at least the second end region of the inner shaft engages the inner surface of the outer shaft, and that at least a portion of the intermediate section has clearance with the inner surface of the outer shaft when the outer shaft is not in bending. A higher frequency mode of vibration is formed when the shaft is in bending.

Abstract: A vibration damping device including an elastic main body portion and a plurality of damping members. Each of the damping members have at least a portion thereof within the elastic main body portion and at least one of the damping members is radially spaced from the longitudinal axis of the elastic main body portion.

Abstract: A hollow golf club shaft including a plurality of diverging and converging substantially frustoconical sections. The sections have respective predetermined substantially constant wall thicknesses.

Abstract: A golf club for impelling a golf ball further with thrust force assist. Pressurized fluid from a fluid pump enters the club through the handle assembly and exits out through a fluid nozzle at the back of the club head. The club thus prepared is swung in the normal way. Due to the added thrust force, the club head velocity is greater than it would be without any assist, causing the ball to be impelled further down the fairway and/or teaching the golfer to swing faster. The club further includes a triggering mechanism to control the flow of fluid into the club.

Abstract: A tubular member for use as a fishing rod, a golf club shaft or the like, in which the member is formed of a plurality of layers containing carbon fiber impregnated with resin, with the layers being overlaid one on another. According to the present invention, the tubular member includes an inner layer formed of carbon fiber and resin and configured into a tubular shape, an intermediate layer including a plurality of layers formed of carbon fiber and resin, and an outer layer formed of carbon fiber and resin and configured into a tubular shape. At least one of the plurality of layers together forming the intermediate layer contains pitch type carbon fiber.

Abstract: A hollow golf club shaft is prepared by flag rolling a base layer of composite material pieces over a mandrel having a larger-diameter region and a reduced-diameter region. The base layer is optionally precompacted. A collar is slid along he length of the mandrel having the reduced-diameter region and base layer to lie adjacent to the larger-diameter region, and at least one overlayer composite material piece is flag rolled overlying the base-layer composite material pieces onto that portion of the mandrel having the reduced diameter.

Abstract: A composite shaft used in the manufacture of golf clubs includes a straight shaft of tapered form extending between an upper butt end a lower tip end. A radially outwardly protruding bulge section is located on the shaft with the bulge section being spaced from both the tip end of the shaft and the butt end of the shaft. The bulge section has a relatively short length compared to the length of the shaft and is located on the shaft to begin in the lower 1/3 of the shaft length.

Abstract: In the field of golf equipment, a new shaft design incorporates passive damping to suppress the vibrations excited in the shaft before and after impact. The design comprises a viscoelastic material sandwiched between multiple layers of composite plies which induce large shear strains in the viscoelastic when the shaft is subjected to bending, extension, or twist, thus increasing damping losses over conventional golf shafts. In one embodiment, the sandwiching layers are of opposing orientation. In another embodiment, the layers are oriented in an opposing V-shape laminate.

Abstract: An improved aerodynamic golf club shaft is disclosed. The improved aerodynamic golf club shaft comprises a tube that has an exterior with a non-circular cross section. The golf club shaft may have an elliptical exterior cross section in one preferred embodiment. The golf club shaft has a leading edge that is on the half of the shaft aligned with the face of the golf club and a trailing edge on the half of the shaft aligned with the back of the club. A portion of the leading edge of the shaft has a smaller radius of curvature than the leading edge of a equivalently sized shaft having a circular cross section.

Abstract: Various forms of golf clubs are disclosed, which include one or more inflatable bladders in the golf club head and/or golf club shaft, as well as internal and external grooving of the golf club shaft. Such golf clubs have enhanced characteristics for driving a golf ball to move in a desired trajectory. The unique structural components of the golf club provide for reinforcing, rigidifying, reducing weight and more effective control of the golf club during the swing. A higher club head speed when impacting a golf ball, more stability on off center hits, reduced vibration upon ball impact, improved sound characteristics, and improved "feel" can be achieved.

Abstract: The present invention provides a damper comprising a compressible and resilient shaft and at least one constrained layer damping section attached to the exterior of the shaft via an adhesive. The damper can be compressed and inserted into a cavity or hollow in an article to be damped whereupon it can expand and provide vibration damping properties as well as optional acoustic absorbing properties. The present invention also provides the damped article and a method of damping the article.

Abstract: A sports implement including an electroactive element, such as a piezoceramic sheet attached to the implement and a circuit attached to the electroactive element. The circuit may be a shunt, or may include processing such as amplification and phase control to apply a driving signal which may compensate for strain sensed in the implement, or may simply alter the stiffness to affect performance. In a ski, the electroactive element is located near to the root in a region of high strain to apply damping, and the element captures between about one and five percent of the strain energy of the ski. The region of high strain may be found by modeling mechanics of the sports implement, or may be located by empirically mapping the strain distribution which occurs during use of the implement. In other embodiments, the electroactive elements may remove resonances, adapt performance to different situations, or enhance handling or comfort of the implement.

Abstract: An implement grip having a built-in shock absorber. The shock absorber may have a coiled configuration or interspersed coils. Implements range from sports equipment such as golf clubs, tennis rackets, and baseball bats to tools such as hammers.

Abstract: A golf club shaft is disclosed. The golf club shaft includes an elongated tubular member having an outer surface and a longitudinal axis. The elongated tubular member has a plurality of channels formed about the outer surface of the elongated tubular member and extending substantially parallel to the longitudinal axis. The plurality of channels are shaped and dimensioned to create air flow about the elongated tubular member, reducing air resistance as the golf club shaft is swung by an individual.

Abstract: A golf club having a vibration damping device including a club head, a shaft connected to the club head having resonant frequencies over a predetermined range and a rod disposed within the shaft with a viscoelastic material interposed between the shaft and the rod. The rod is flexible and has resonant frequencies over the same frequency range as the shaft such that the shaft and rod vibrate out of phase with respect to each other and thereby deform the viscoelastic material to damp vibrations in the shaft.

Abstract: An improved putter of the type which has a filled hollow shaft. The improved putter has a shaft which is filled with a resin, which in turn, is filled with micro-balloons. The filling bonds to the interior of the putter shaft and is essentially concompressive giving the putter a vastly improved feel.

Abstract: The invention relates to a golf club by which a soft ball hitting feeling can be obtained while the excellent orientation of a ball peculiar to a hollow metallic head is maintained. A shaft is inserted into a hosel attaching section of a hollow metallic head through a hosel. The head is made of magnesium alloy or aluminum alloy, and the shaft is made of carbon fiber reinforced resin. The hosel is made of synthetic resin, the rigidity of which is lower than that of the shaft.

Abstract: Tubular golf club shaft made from composite materials comprising layers of fibers impregnated with plastic resin and provided over its length with at least one are of enlargement (6) and or narrowing. The curve of generation of the internal diameter of the shaft as a function of its length beginning at the point of the smallest internal diameter and extending to at least one of the ends of the shaft incorporates at least one decreasing portion.

Abstract: A composite shaft used in the manufacture of golf clubs includes a straight shaft of tapered form extending between an upper butt end a lower tip end. A radially outwardly protruding bulge section is located on the shaft with the bulge section being spaced from both the tip end of the shaft and the butt end of the shaft. The bulge section has a relatively short length compared to the length of the shaft and is located on the shaft to begin in the lower 1/3 of the shaft length.

Abstract: Golf clubs, golf shafts, and inserts for golf club shafts have a coil or coil-type insert for enhancing swing weight control, stiffness and flex control, shock absorption and vibration elimination or reduction. The insert has a central section and a pair of couplers integrally formed on opposite ends of the central section to attach to the shaft or club head.

Abstract: A tubular member for use as a fishing rod, a golf club shaft or the like, in which the member is formed of a plurality of layers containing carbon fiber impregnated with resin, with the layers being overlaid one on another. According to the present invention, the tubular member includes an inner layer formed of carbon fiber and resin and configured into a tubular shape, an intermediate layer including a plurality of layers formed of carbon fiber and resin, and an outer layer formed of carbon fiber and resin and configured into a tubular shape. At least one of the plurality of layers together forming the intermediate layer contains pitch type carbon fiber.

Abstract: A vibration dampening insert for use in golf clubs includes a plug member located inside a shaft of a golf club. The plug member has a plurality of cavities formed therein, and a plurality of spherical weight members are disposed in the plurality of cavities. The plug member is made of an elastomeric material, and the spherical weight members consist of steel balls. The vibration dampening insert dampens vibration resulting when a club head of a golf club impacts a golf ball so that vibration is prevented from being transmitted to a golfer who is swinging the golf club.

Abstract: A system measures and records deflection of an elongated shaft such as the shaft of a golf club and provides a trace or diagram of the swing of the club. The system includes an elongated rod, mounted to the golf club shaft, and a separate recording system. Preferably the recording system is a writing platform mounted to the golf club shaft. The recording member is biased into contact with the writing platform. During swing of the golf club, deflection of the golf club shaft causes relative movement between the writing implement and the writing platform and a trace or diagram of the golf club swing is created.

Abstract: An elongate tube of resilient material is fitted into a golf club shaft to reduce the transfer of impact shock to a golfer's hands, shoulders and arms. The tube is compressively fitted into the club shaft to protect against its slippage or movement within the shaft. The tube when inserted also does not alter or affect club balance. For additional shock absorbency, the club face may be isolated from the remainder of the club head by a layer of resilient, shock-absorbent material. The tube may also be used as an insert in shafts or handles of other types of sporting goods.

Abstract: A substantially tubular rigid golf club shaft made of a composite of structural fiber laminate in a resin matrix, the shaft comprising a grip portion, a medial portion and a head attachment portion,the grip portion having a upper grip end and a lower grip end and being constructed and configured for a grip to be mounted on said grip portion that covers the exterior surface of the grip portion and extends substantially the entire length of said grip portion from said upper grip end to said lower grip end,the medial portion having a upper medial end adjacent to the lower grip end and extending a lower medial end adjacent to the head attachment portion,the head attachment portion having a upper head attachment end and a lower head attachment end with the upper head attachment end adjacent to the lower medial end, the head attachment portion constructed and configured for a golf club head to be mounted on said head attachment portion,a step transition in the exterior surface of the shaft that abruptly increases t

Abstract: A hollow golf club shaft including a plurality of diverging and converging substantially frustoconical sections. The sections have respective predetermined substantially constant wall thicknesses.

Abstract: A golf club is disclosed having a shaft fixedly connected to a grip and a head. The shaft is comprised of a tube with a rod extending through the tube. The rod is fixedly attached to the head and the grip. Various nonresilient disks are located around the rod to assist in connecting the rod to the grip. Further, resilient disks are located about the rod between the grip and the head to inhibit transverse motion of the rod within the shaft and to attenuate various modes of vibration.

Abstract: A vibration damper device (1) intended to be mounted on a sports article such as, in particular, a tennis or squash racket, a gliding board or a golf club, whereinthe device includes at least two elements (3, 4) superposed to form a stack and mounted so as to slide relative to one another, each element (3, 4) in said stack being secured to the article by one end, the ends (13, 14) of the adjacent elements being offset relative to one another so that the deformations of the article (8) due to the vibrations cause the adjacent elements (3, 4) to slideand at least one of the superposed elements (4) is magnetized, one of the other elements (3) in the stack being made of a material which is sensitive to the magnetic field generated by the magnetized element (4).

Abstract: A golf club shaft has the usual handle portion at one end, a golf club head ounting portion at the opposite end, and a tapered intermediate portion therebetween. The tapered intermediate portion includes a substantially inflexible section adjacent the handle portion and a substantially flexible section adjacent the club head mounting portion. With this arrangement, rather than the entire shaft flexing in a substantially smooth curve during a normal swing of the club, the flexing is limited to the substantially flexible section of the club. This provides a club with increased control.

Abstract: A golf club having a vibration damping device including a club head, a shaft connected to the club head having resonant frequencies over a predetermined range and a rod disposed within the shaft with a viscoelastic material interposed between the shaft and the rod. The rod is flexible and has resonant frequencies over the same frequency range as the shaft such that the shaft and rod vibrate out of phase with respect to each other and thereby deform the viscoelastic material to damp vibrations in the shaft.

Abstract: Various tools and devices, such as golf clubs, are improved by the incorporation of a vibration absorbing material having a hardness of less than 40 durometer reading, a coefficient of friction of at least 0.6 and a dampening vibration greater than 55%. When used for a golf club the material can be incorporated in the handle part of the shaft to improve the grip, can be inserted down the inside of the shaft to increase vibration absorption and a more solid contact or can be incorporated in the club head.

Abstract: A golf club with one or more annular grooves formed on the outer circumferential surface of the hosel portion of the head, the hosel portion being provided with an outwardly widened tapered surface on the inner circumferential surface of the opening end of a shaft insertion hole of the hosel portion, thus preventing brakeage of the shaft by way of the groove(s) and the tapered surface. The grooves can be filled with non-rigid cosmetic members for a better appearance.

Abstract: A golf club 10 includes a shaft 12 with a grip 14 assembled on a butt end 16 of the shaft. A club head 18 is mounted on a tip end 20 of the shaft 12. The shaft 12 is composed of steel and is formed with an intermediate section 22 having a plurality of sections 22a through 22n of decreasing diameter from the butt end 16 toward the tip end 20. A bulge 24 is formed in the shaft 12 near an inboard extremity of the tip end 20. The bulge 24 is formed with a central cylindrical section 26 with three cylindrical step surfaces 30, 32 and 34 at one axial end of the section 26 and three step surfaces 36, 38 and 40 at the opposite axial end of the section 26. The diameter of the central section 26 is greater than the diameter of the immediately adjacent portions of the shaft 12.

Abstract: A golf club providing the golfer control over internal pressure therewithin to thereby most advantageously fine-tune the performance of the golfer's golf club. The selectively pressurized golf club is composed of either a hollow head, a hollow shaft, or both hollow head and hollow shaft, either or both of which being selectively pressurized, separately or as one, either above or below atmospheric pressure. In the preferred embodiment, the gas pressure within the golf club is selectively accessed by the golfer via a valve mounted thereto, such as for example a pneumatic valve or an elastomeric valve. The head may have its own valve and its separate pressurizable internal chamber; the shaft may have its own valve and separate pressurizable internal chamber; or one valve may be present for selectively changing pressurization within fluidically communicating shaft and head internal chambers.

Abstract: A golf club shaft including a damping layer which serves to reduce the amplitude of vibrational waves subject upon a golf club shaft is provided. The damping layer which includes, at least in part, an elastomeric material is coated to the inner diameter of the golf club shaft along a desired length. A method is also provided which relates to reducing the effects of induced modes of vibration upon a golf club shaft.

Abstract: A shock absorbing golf club is disclosed that is adapted to minimize the transfer of shock to the hands of the golfer and reduce possible damage to the shaft of the club as a consequence of the impact force that is typically generated should the golf club head inadvertently strike the ground in advance of the golfer's ball. The foregoing is accomplished by the shaft of the golf club sliding axially and reciprocally through the grip which surrounds the shaft. A compression spring is located within the grip to receive and dissipate the impact force that is transmitted from the club head to the shaft to cause the shaft to slide through the grip towards the spring.

Abstract: The invention relates to a shaft for a golf club, or to a club equipped with such a shaft. On at least 30% of the length of the shaft, its peripheral wall includes at least two layers, i.e., a first layer made of a material of density (.rho.1) and of longitudinal Young's modulus (E1), and a second layer made of a material of density (.rho.2) and of longitudinal Young's modulus (E2), the first and second layers being separated by a separation layer made of a substantially isotropic material having a density (.rho.3) and a longitudinal Young's modulus (E3), the densities (.rho.1, .rho.2) of the materials of the first and second layers being greater than the density (.rho.3) of the material of the separation layer, the longitudinal Young's moduli (E1, E2) of the materials of the first and second layers being respectively greater than 20 GPa, and the longitudinal Young's modulus (E3) of the material of the separation layer being lower than 20 GPa.

Abstract: In a golf club an outer tube is installed between the soft grip and the shaft. The outer tube is a rigid, hollow tubular structure, which covers at least partially the handle portion of the shaft, the improvement comprising a provision of space for bending movement and structural support between the shaft and the outer tube such that when the shaft is bent during impact of the head with a golf ball, the outer tube does not interfere with the bending movement of the shaft.

Abstract: A golf club stabilizer having a plurality of rubber discs all connected to a single threaded rod. In one embodiment, all of the discs can be expanded into contact with the shaft of the golf club uniformly or they can be varied in selectively different amounts. The discs can all be tightened to make the club very stiff or they can be tightened only loosely to make the club more stiff than without the discs but less than with fully tightened discs, The kick point of the club can also be varied by leaving some of the discs in a relaxed state out of contact with the shaft and doing this with any of the discs along the several discs in the club. In another embodiment, the discs of a diameter greater than the internal diameter of the shaft can be connected to the rod, lubricated, and forcibly pressed into the shaft.

Abstract: A low-torque lightweight shaft and a laminar structural element and method for its manufacture are described. The invented shaft is fabricated by fabricating a laminar structural element in the form of a planar sheet or blank patterned and sized for spirally, rather than helically, wrapping around a mandrel. The laminar structural element preferably includes oppositely angularly biased plies interposed by a longitudinally or "zero" oriented ply of any suitable binder-containing, oriented boron or carbon fiber-filled polyacrylonitrile (PAN) sheet material. Preferably, another zero orientation ply, prior to wrapping, is placed above one of the bias plies, thereby ensuring complete separation of the opposing bias plies in the finished shaft. Typically, each ply is approximately 4-6 mils thick and the overall wall thickness of the wall of the finished shaft is approximately 30 mils, rendering the shaft approximately 30% thinner, and significantly lighter in weight, than conventional shafts.