WO2015143306A1

WO2015143306A1 - Articulated butt end improvement on handheld rackets, bats and clubs

Info

Publication number: WO2015143306A1
Application number: PCT/US2015/021727
Authority: WO
Inventors: Bruce Wright; Zoltan A. Kemeny
Original assignee: Bruce Wright; Kemeny Zoltan A
Priority date: 2014-03-20
Filing date: 2015-03-20
Publication date: 2015-09-24

Abstract

Disclosed is an articulated apparatus to be inserted into the butt end of the shaft of handheld sporting hitting devices (rackets/clubs, bats/cues) used to hit balls in games (tennis, baseball, cricket, golf, hokey, pool and such), comprising at least one rigid body attached by at least one flexible body (isolator) with essentially rigid means (vulcanized/glued/pried-in), tuned as an insert to at least one Eigen frequency of said device (including the fundamental one), and to that of the stiffened body of the player at least in part (arm/shoulder/torso) and at least in the direction of the ball hit, for significantly shifting the center of mass, center of percussion, vibration nodal point and the sweet spot in order to reduce chances of injury to players, reduce player fatigue, reduce player strength demand and thereby improve the game in a measurable extent perceivable as meaningful at least by the players of said games.

Description

ARTICULATED BUTT END IMPROVEMENT ON HANDHELD RACKETS, BATS AND

CLUBS

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of United States Provisional Patent Application Serial

Number 61/967,482 of priority date 03/20/2014.

Field of the Invention

This invention relates to sporting goods, including tennis rackets, baseball bats, golf clubs and such, having articulation at the butt end under the gripping length with apparatus inserted to improve the game and to ease player effort or avoid arm, shoulder and back injuries. More particularly to butt end mass-spring systems frequency tuned based on accelerometer readings.

Background of the Invention The invention aims to improve the game of sports involving hand gipped devices hitting balls, such as rackets, bats, clubs and cues, in order to avoid player injury, improve the game and comfort the player providing more ease, control, precision, feedback and power.

Inventors focused before on means to alter such devices by means affecting center of mass and vibration nodal points, but neglected tailoring total weight to player's strength and weight or injured condition, as well as dynamic properties related to other than the direction of ball hitting. Most predominantly, all neglected longitudinal and across free motion attenuation, which however has strong influence of percussion and thus over the game controls and player body responses.

Almost exclusively, all inventors proposed altering the center of mass location by adding or redistributing weights far from the butt end in the vicinity of the ball hitting area. Vibration attenuators and absorbers with meaningful weight were proposed to locate far from the butt end thereof. The butt end attenuators offer unique opportunities to achieve even more benefits, however at the expense of significant weight addition, which for long was opposed by the sporting industry in the contest of producing ever lighter rackets, bats and clubs. That trend now reached its technological limits. For instance, a tennis racket for adult players now weighs as low as 280 grams. To ensure sufficiently high stiffness became a great challenge thereof. The high racket vibration is now very annoying and makes playing tiresome. In professional games, a reverse trend is prevalent with preference of heavier rackets. Players now demand rackets tailored for better control or power (or both if possible) as well as for beginner, professional, injured, recovering, training, practicing, young and adult players of weak or strong muscles.

This invention recognizes that the most efficient location to achieve these goals and to harmonize between conflicting ones, is at the butt end, alas at the price of adding heavier apparatus to a light racket, say 5-25% racket weight. By proper tuning, the weight balance and the percussion location can be optimized to all the above listed conditions. However, it would be mostly advantageous, if the added butt end apparatus, could be tuned dynamically to the free vibration properties— or at least to the first few Eigen values— of the racket. Also, to such properties of the player's arm, shoulder and torso to the extent possible by their reliably measurable dynamic properties at stiffened and loosened muscle conditions. Furthermore, to use simple tuning by turning a knob to alter the mass-damper stiffness, or adding washers, or extending bars and such, based on accelerometer measurements, preferably using accelerometers built into the mass to be tuned. This approach and the introduction of double tuning, i.e. one to the racket and one to the body, is novel and so is the proposed enabling apparatus proposed here.

Therefore, the object of the invention is to provide passive mechanical means for single or double tuning of butt end inserts of at least 5% racket/bat/club/cue weight at least in one direction of interest, which mostly the direction of the ball hits. Summary of the Invention

Disclosed is a method and apparatus for improving the performance of a hand-gripped sporting device such as a tennis racket/golf club by utilizing weights mounted in the butt end. The weights are selected based on either or both the player's ability and the frequency characteristics of the racket. The weights are selectively rigidly or elastically mounted to the butt end with respect to X, Y, and Z axes as shown in FIG. 1. The mounting may be rigid or compliant with respect to each axis. Determination of the mounting characteristic is determined by one of several methods as set forth below. The method and device may be used on the butt end of hand-gripped tennis/baseball/golf/cricket/polo/pool (hereinafter tennis) racket/bat/club/cue (hereinafter racket) composed of at least one heavy attachment through resonant means at least in the direction of the ball hitting, tuned in one part to the dynamics of said racket and another part to that of the player's arm/shoulder/torso/body for the improvement of the game, avoidance of injuries and comfort of the player, hitting a ball with said racket.

The device may be

a) heavy butt end attenuation capsule, or

b) isolation butt end capsule, or

c) socketed/mounted isolation inserts, either

orthotropic or orthogonal and elastic or viscoelastic mass attachments of single or multiple degree of freedom, affecting the racket's

d) center of mass,

e) center of percussion,

f) vibration nodal point,

g) sweet spot (except for cues),

h) total weight,

tuned to either the

i) racket/bat/club/cue weight,

j) player's body/torso/arm weight,

k) racket/bat/club stiffness,

1) player's strength

whereas said tuning is based on

m) calculations

n) accelerometer measurements

o) try-and error adjustments. In particular, accelerometer measurements obtained from accelerometers mounted on at least one mass to be tuned.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the drawings:

Fig. 1 is a perspective view of a tennis racket butt end with reference coordinate system.

Fig. 2 is a perspective view of a tennis racket butt end with attenuation butt end.

Fig. 3 is a perspective cutaway view of a tennis racket butt end with isolation butt end.

Fig. 4 is a perspective view of a tennis racket butt end with light-weight socketed isolation butt-end insert.

Fig. 5 is a perspective view of a tennis racket butt end heavy-weight socketed isolation butt-end insert.

Fig. 6 is a perspective view of a tennis racket butt end with heavy-weight socketed isolation butt-end insert.

Fig. 7 is a perspective view of a tennis racket butt end ultra-heavy-weight socketed oneway-isolation butt-end insert.

Fig. 8 is a perspective view of a tennis racket butt end with ultra-heavy-weight socketed one-way-isolation butt-end insert.

Fig. 9 is a perspective view of a tennis racket butt end super-heavy-weight socketed and lipped one-way-isolation butt-end insert.

Fig. 10 is a perspective view of a tennis racket butt end with super-heavy- weight socketed and lipped one-way-isolation butt-end insert.

Fig. 11 is a perspective view of a tennis racket butt end mid-range-weight socketed oneway-isolation button-end insert.

Fig. 12A is a perspective edge view of a tennis racket butt end with high-range -weight socketed one-way-isolation button-end insert.

Fig. 12B is a perspective frontal view of a tennis racket butt end with high-range-weight socketed one-way-isolation button-end insert.

Fig. 13 is a perspective view of a modified tennis racket butt end insert socket.

Fig. 14 is a perspective view of a tennis racket butt end ultra-high-range-weight socketed one-way double-isolation button-end insert.

Fig. 15 is a perspective view of a tennis racket butt end with ultra-high-range-weight socketed one-way double-isolation button-end insert.

Fig. 16 is an isometric view of a tennis racket butt end ultra-high-range-weight socketed one-way double-isolation button-end insert with hidden tuning-brush appendage. Fig. 17 is an isometric view of a tennis racket butt end with ultra-high-range-weight socketed one-way double-isolation button-end insert with hidden tuning-brush appendage.

Fig. 18 is an isometric view of a tennis racket butt end ultra-high-range-weight socketed single-piece one-way double-isolation button-end insert with hidden tuning-brush appendage and button mount.

Fig. 19 is an isometric view of a tennis racket butt end with ultra-high-range-weight socketed single-piece one-way double-isolation button-end insert with hidden tuning-brush appendage and button mount.

Fig. 20 is a perspective view of a tennis racket butt end high-range-weight socketed two- piece double-isolation button-end insert with hidden attenuator.

FIG. 21 is a perspective view of a tennis racket butt end high-range-weight socketed two- piece double-isolation button-end insert with built in telemetric accelerometer and turn button tuning capability.

Fig. 22 is an isometric view of the same, shown in longitudinal cross section.

Fig. 23 is an isometric view of the insert illustrated in Fig. 21 and 22.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Attention is now turned to FIG. 1, which by assembly 10, illustrates an exemplary butt end handle part of a tennis racket structure 1 1 for defining coordinate directions X, Y and Z, used in the invention for further explanations.

Structure 1 1 is an extruded aluminum channel of a l_l/8"x l_3/8" ID (Χ·Υ) octagonal section with 1/4" corners chopping and 1/32" wall thickness. Its length is shown only up to 4" (Z) where the player grips it. The tennis ball is hit in direction X. The racket is soft in direction X, stiff in direction Y, and rigid in direction Z. Sizes, distances and dimensions here are merely exemplary. Direction X is the action direction, i.e. the direction of the ball hitting. Direction Y is the transversal, while Z is the longitudinal direction, both are "near-dead" or "dead" directions, respectively, for having small or marginal influence on the racket dynamics relevant to the game. For baseball bat however, both the X and Y directions are active, though once at the time.

Assembly 10 also represents baseball bats, golf clubs and such sporting good handles, though these have variable cross sections, including elliptical, round and rounded rectangular or square. In any case the ball, subject of the game, is hit with the device with contact far from the butt end, where it is gripped by the player. Further discussion will thus refer only to tennis racket, but with the understanding of the applicability of the other mentioned devices.

Attention is now turned to FIG. 2, which by assembly 20, illustrates in perspective view the hand gripped portion of a tennis racket butt end shaft 11 with mounted attenuation butt end cup 21, as an exemplary preferable embodiment of the invention.

Cup 21 is preferably heavy, e.g. made of metal or ceramic powder in resin or carved out from gemstone or hardwood or such, and mounted to shaft 11 by a layer of attenuation tape, which has no elasticity but damping, like for instance a double sided sticky back felt tape. The base of cup 21 may have inward protrusions fitting into shaft 11 (not shown). Such protrusions or extrusion shall however clear shaft 1 1 by said attenuation material or by air.

Note here that there are traces in prior art of weight mounting at the butt end, however only as rigid mounts, using bolts or screws or glues. Those behave dynamically differently from the one illustrated in FIG. 2. So do heavy cups with isolation mount, which is illustrated next. Attention is now turned to FIG. 3, which by assembly 30, illustrates in perspective cutaway view of a tennis racket butt end shaft 1 1, with isolation butt end cup 31 , filler isolation sleeve 32 and backer isolation pad 33. Sleeve 32 and pad 33 are of solid or spongy elastomers having predominantly elasticity but no damping in a significant extent. To lower their stiffness in short layer thickness, arrays of holes, apertures or other articulations, as cut outs may be employed. The layer thicknesses and stiffnesses may be different in X, Y and Z directions. The natural frequency of the mounting can be at or above or under the first mode free vibration frequency of the racket of which shaft 1 1 is part of by even-or-odd integer multiples or fractions. These Eigen frequencies may be different in X, Y and Z directions. This harmonization may be tuned to player arm mechanics or racket dynamics or both, with special focus on impact transients.

For instance, the mounting frequency can be lx, 4x and 8x in X, Y and Z directions respectively of the corresponding free body frequencies of the racket. Cup 31 may measure approximately between 5-25% of the racket. More weight ensures more power and less control over the ball hitting by arm swing. Less weight has the opposite effect. More isolation results in more body comfort and more damping in less fatigue of the player. Children and injured professionals in recovery may opt for more isolation with more damping with less heavy cup. Such strategic graduation and administration of racket dynamics modification at the butt end have not been possible before this invention. Heavier cup 31 pushes the center of percussion away from the butt end and pulls the center of mass towards it. Both affect slice and spin transfer to the ball. Effective results have been achieved by selecting a weight from a weight set. The weight set includes rigid bodies having one of four values, 15, 30, 45, and 60 grams. The weight can be determined by determining the player's skill level and selecting the weight according to the above principle or can be determined by accelerator lab testing to determine the racket's natural vibration frequency or by use of an accelerometer mounted to the racket. These methods are disclosed below. The rigid body can be any suitable material such as metals of higher than 10 KSI yield strength including steel, stainless steel, bronze, copper and aluminum, carbon or glass reinforced plastics.

Attention is now turned to FIG. 4, which by assembly 40, illustrates in perspective view of a tennis racket butt end with light-weight socketed isolation butt-end insert. Assembly 40 is composed of shaft 1 1, state-of-art plastic end cap 41 with receiving socket, lips and screwdriver slots, as well as pop-in insert 42 with elastomer base plate 43 with glued-on metal or otherwise heavy logo plate, while insert 42 is shown removed from said socket. Plate 43 may have cut out to lower stiffness in directions X and Y. It may also be made of spongy rubber or similarly soft material, including felt, which has no elasticity but damping. Compacted felt attenuate vibration set up by the ball hit within the first half cycle— that is extremely effectively.

It works similarly to the previous embodiment shown in FIG. 3. Its advantage is of being suitable for retrofitting rackets with small apparatus fulfilling the aims of the invention, alas in a limited extent. It is more effective in children's racket than in pro adult ones. It is extremely manufacturer and aftermarket friendly.

Attention is now turned to FIG. 5, which by assembly 50, illustrates in perspective view of a tennis racket butt end heavy-weight socketed isolation butt-end insert, suitable to pop-in the above shown standard socket.

Assembly 50 is composed of base plate 51 (same as plate 42, though could be of different material), elastomer plate 52 vulcanized or glued on both sides, appendage plate 53 with dome shape extrusion 54. Plate 51 has two keyways 55 to facilitate insertion and removal by a screwdriver. Instead of gluing, plate 52 may be popped-in to both plate 51 and 53 via lipped protrusion. That would facilitate its quick replacement by plate 52 of different softness or damping to achieve desired tuning experimentally by try-and-error.

Again, plate 52 can have cut outs or can be spongy (containing bubbles) or soft solid as shown. Due to the heavier weight of plate 53 and dome 54, this embodiment allows for more meaningful tuning. Its use is illustrated by assembly 60 in FIG. 6 in cap 41 which is rigidly attached to shaft 1 1. Further refinement of it is illustrated next.

Attention is now turned to FIG. 7, which by assembly 70, illustrates in perspective view of a tennis racket butt end ultra-heavy- weight socketed one-way-isolation butt-end insert.

Assembly 70 is composed of rigid baseplate 61 (same as or similar to plates 42 and 51), channeled elastomeric spacer 62, domed plate 63 with dome 64, while spacer 62 has through channels 63 to make insert 70 more compliant in direction X. Apart for thicker and channeled elastomer and the heavier domed plate and larger dome, insert 70 is the same as insert 50. Its use is illustrated by assembly 80 in FIG. 8, which includes shaft 1 1 with socket 41 and insert 70. The elastomeric spacer is formed of an elastomer having a Durometer hardness in the range between 20 and 80 and includes natural rubber, polyurethane, plastic, and silicone rubber. Further refinement follows next. Attention is now turned to FIG. 9, which by assembly 90, illustrates in perspective view of a tennis racket butt end super-heavy-weight socketed and lipped one-way-isolation butt- end insert.

Assembly 90 is composed of baseplate 91 (same as plates 61, 42 and 52) channeled elastomeric spacer 92, domed and lipped plate 93 with dome 94. The lip around mostly closes the gap and adds more weight. Otherwise works as insert 70. Its use is illustrated in FIG. 10, by assembly 10, which includes shaft 1 1, socket cap 41 and insert 90. Though spacer 92 is thick, the gap between insert 90 and cap 41 remains small. Insert 90 is also softer in direction X than in directions Y and Z. More rounded butt end shapes are however preferred by some. Another improvement is illustrated accordingly next.

Attention is now turned to FIG. 1 1, which by assembly 1 10, illustrates in perspective view of a tennis racket butt end mid-range-weight socketed one-way-isolation button-end insert.

Assembly 110 is composed of baseplate 1 11 (same as plates 91, 61, 42 and 52) channeled elastomeric spacer 112, domed plate 113 with dome 114. It works as insert 70 and 90.

The use of assembly 110 is illustrated— in edge view— in FIG. 12A, by assembly 120, which comprises shaft 1 1, lipped socket cap 41 and insert 11 OA, which is the same as insert 110, but with lips under the dome. Again, though spacer 112 is thick, the gap between insert 11 OA and cap 41 remains small. Insert 11 OA is also softer in direction X than in directions Y and Z. Assembly 120 is also illustrated— however in frontal view— in FIG 12B, where the labels are the same as in FIG. 12A. Further improvements are introduced next.

Attention is now turned to FIG. 13, which by assembly 130, illustrates in perspective view of a modified tennis racket butt end insert socket, having side walls 131, end wall 132, base 133, clearing wall 132 by gap 134, whereas base 133 has through broken opening 136, to allow insert protrusion inward shaft 1 1. Such intruding inserts will be disclosed now. Attention is now turned to FIG. 14, which by assembly 140, illustrates in perspective view a tennis racket butt end ultra-high-range-weight socketed one-way double-isolation button- end insert. Assembly 140 is composed of base plate 141 (same as plates 1 11, 91, 61, 42 and 52 at least in geometry) with keyway 142 for screwdriver prying, button mounting elastomer 143 with Y-way channels 144, domed plate 145 with dome 145 A, lip 146, inner mass mounting elastomer 147 with channels 148 in direction Y, glued on or vulcanized inner mass base 149A as a common body with inner mass appendage 149B.

The use of assembly 140 is illustrated in FIG. 15 by assembly 150, which includes shaft 1 1, cap 130 and insert 140. The outer domed mass may thus be tuned to the player arm, while the inner cylindrical mass to the racket. Such a possibility was unavailable before this introduction of this novelty. Further configurations will eliminate the use of elastomer, one by one.

Attention is now turned to FIG. 16, which by assembly 160, illustrates in isometric view of a tennis racket butt end ultra-high-range-weight socketed one-way double- isolation button-end insert with hidden tuning-brush appendage. Assembly 160 is composed of metallic base plate 161 (same as or similar to plates 141, 11 1, 91, 61, 42 and 52 at least in geometry), elastomeric mounting plate 163 with Y-way through channels 164, lipped outer mass plate 165 with ellipsoid dome 166 and inner mass tuning fork brush array 167, which is a common body with plate 162. The advantage of this configuration is that it is built of less parts. It is more metallic and less aging. Since the metallic tuning forks have no damping, unless that is added by a foam, it requires more precise tuning to the fundamental frequency of the racket. Its use is illustrated in FIG. 17 in isometric view by assembly 170, which comprises shaft 11, cap 130 and insert 160. Next the complete elimination of elastomers form the insert is disclosed.

Attention is now turned to FIG. 18, which by assembly 180, illustrates in isometric view of a tennis racket butt end ultra-high-range-weight socketed single-piece one-way double- isolation button-end insert with hidden tuning-brush appendage and button mount. Assembly 180 is composed of metal base plate 181 (same as plates 161) with keyway cut outs 182, mounting columns 183, outer mass plate 184 with lip 185 and dome 186, and tuning fork brush 187, all as a single piece metal, preferably printed in 3-D or cast. Obviously, brush 187 may be considered the flexible mounting of a weight confining the tips of it (not shown).

This configuration has the advantage of being made of one material in one piece, which makes it extremely manufacturer friendly. Its use is illustrated in isometric view in FIG. 19, which comprises shaft 1 1, cap 130 and insert 180. This insert has no damping, unless added by foams. One such foam damper is illustrated next in a final configuration.

Attention is now turned to FIG. 20, which by assembly 200, illustrates in isometric view of a tennis racket butt end with ultra-high-range-weight socketed single-piece one-way double-isolation button-end insert with hidden tuning-brush appendage and button mount.

Assembly 200 is composed of base plate 201 (same as 52), foam rubber outer mount 202, outer mass plate 203 with dome 204 and lip 205, foam rubber inner mount 206, inner mass 207 and spacer foam 208, which has little elasticity but high damping. Foam 208 fills the space between mass 207 and shaft 11. Such foam may be used attenuate the free body vibration of the above shown metallic mass tuning columns or brushes.

Mounts 202 and 206 may be glued or vulcanized for attachments to plate 203 and mass 207 respectively. Mounts 202 and 206 may also have protrusions or intrusions with collar or socket shoulder to be fixed to plate 203 and mass 207. Mounts 202 and 206 may be cast as a common body with necking at plate 201, while in that case plate 201 can be split to two halves to fit to that necking, while cup 41 would join said two halves. These and other common techniques may be used to join parts in insert 200— and in all the disclosed preferable inserts— invariably and indistinctively, thus are not shown in further detail. Attention is now turned to FIG. 21, which by assembly 300, illustrates in isometric view of a tennis racket butt end with ultra-high-range-weight socketed single-piece one-way double- isolation button-end insert with built in telemetric accelerometer and turn button tuning capability. Assembly 300 is composed of shaft 1 1 and double tuning butt end insert 400. Insert 400 is smooth and almost flush with shaft 1 1, thus does not interfere with racket end gripping.

Attention is now turned to FIG. 22, which by assembly 300, illustrates in longitudinal cross section of the tennis racket butt end with ultra-high-range-weight socketed single-piece one-way double-isolation button-end insert with built in telemetric accelerometer and turn button tuning capability, shown in Fig. 21.

Assembly 300 is composed of shaft 11 and double tuning butt end insert 400. Assembly 400 comprises of octagonal tuned mass damper socket 401, soft elastomeric articulated washer 402, butt end extended exterior button shape primary mass 403, telemetric accelerometer electronics insert 404 with microchip mounted accelerometer 404A, soft elastomeric sleeve 405, and rod shape secondary mass shaft 406. Shaft 406 is threaded into sleeve 405. Sleeve 405 is threaded into primary mass 403. Primary mass 403 is threaded into socket 401. Said threads are used to adjust the mounting stiffness values of said primary and secondary masses. Socket 401 is press-fit into shaft 1 1.

Primary mass 403 and secondary mass 406 are heavy density rigid bodies, preferably of aluminum, stainless steel or bronze. Socket 401 and sleeve 405 are made of soft elastomer, such as polyurethane or rubber of low Durometer hardness between 20 and 80. Washer 402 is foamlike elastomer of the same or similar material. Its stiffness is barely relied upon. The washer closes the gap to keep unwanted materials out, so nothing can get stuck, including the hand of the player.

Mass 403 forms a primary tunable mass-damper with socket 401 and washer 402. This is tuned to the player's arm by turning mass 403 clockwise (tuning up) or counterclockwise (Tuning down). Mass 406 forms a secondary tunable mass-damper with sleeve 405. This is tuned to the racket by either turning sleeve 405 or shaft 406 or both. When shaft 406 protrudes more from socket 405, the secondary mass-damper is tuned down (reducing or cancelling slow racket vibrations), otherwise it is tuned up (reducing or cancelling fast racket vibrations).

Telemetric accelerometer electronics module 404 is threaded into mass 403. Electronics module 404 has 3-D accelerometer 404A on microchip and data reading, logging, processing and transmitting electronics, including battery and antenna. A suitable data module is manufactured by Babolat and is known as Babolat Play Pure Drive. The module includes software which identifies the first Eigen frequency of the racket and the Tuned-Mass-Damper (TMD).

Data is captured on the player's mobile phone, uploaded to the cloud and displayed or stored for future use. After a short game, the applet suggests adjustment in mass-damper setting for both the primary and the secondary mass-dampers. It would tell for instance to turn mass 403 clockwise 45° and leave mass 406 as is. It may tell otherwise, or give different instructions for both. In any case, it greatly simplifies tuning. Washer 402 can be made of hard rubber or rigid plastic or metallic however. That is useful to separate primary and secondary tunings, to program the data processor and to alter the racket dynamics otherwise. That brings the racket center of mass closer to the gripping fulcrum.

Similarly, sleeve 405 can be made rigid for similar tuning separation and fulcrum shift.

If the adjustments by altering the stiffness turning the parts as disclosed is insufficient for the desired tuning, the applet may suggest using larger or smaller masses. That is achieved by replacing mass 403 or 406 or both by different density material parts. For instance, replacing aluminum by stainless steel, or that by bronze or vice versa, as the applet program should suggest.

The accelerometer package may be threaded over the protrusion of shaft 406. In fact that may not need to eliminate accelerometer package 404. The two can communicate wirelessly and can make the tuning process sharper and faster.

There are several ways to tune the two mass-spring systems, each called also as Tuned-Mass- Damper (TMD) illustrated in FIG. 23, as follows.

TMD-1 is the primary mass-damper, composed of primary mass 403, having a mass of ml, and springs 401-402-405, commonly called here primary spring, having a stiffness of kl. TMD-1 is tuned to the player arm spring-mass system, which composed of the player's arm mass, denoted by Mp, and the player's arm stiffness, denoted by Kp. There are standard methods to measure these mass and stiffness values. The first Eigen frequency of TMD-1 is defined as fl = (l/2n)(kl/ml)^Al/2. The first Eigen frequency of player's arm is defined as Fp = (1/2π)(Κρ/Μρ)^Λ1/2. Tuning is achieved by selecting the ratio of Fp/fl to 1 : 1, 2: 1, 3: 1 N: l, where N<8. Other tunings observe the same ratios for fl/Fp. Various degrees of vibration attenuation is achieved at said frequency ratio setting. As N goes up, the added attenuation diminishes. For the same player, said ratios can be altered by altering either ml, kl or both in TMD-1. By properly tuning TMD-1, the vibration of Mp can be reduced or eliminated, so less strain is felt by the player.

TMD-2 is the secondary mass-damper, composed of secondary mass 406, having a mass of m2, and secondary spring 405, having a stiffness of k2. TMD-2 is tuned to the tennis racket spring- mass system, which composed of the racket mass, denoted by Mr, and the racket stiffness, denoted by Kr. There are standard methods to measure these mass and stiffness values.

The first Eigen frequency of TMD-2 is defined as f2 = (l/2n)(k2/m2)^Al/2. The first Eigen frequency of the tennis racket is defined as Fr = (l/2n)(Kr/Mr)^Al/2. Tuning is achieved by selecting the ratio of Fr/f2 to 1 : 1, 2: 1, 3: 1 N: l, where N<16. Other tunings observe the same ratios for fl/Fp. Various degrees of vibration attenuation is achieved at said frequency ratio setting. As N goes up, the added attenuation diminishes. For the same player, said ratios can be altered by altering either m2, k2 or both in TMD-2. By properly tuning TMD-2, the vibration of Mr can be reduced or eliminated, so less strain is felt by the player, because the racket vibration propagates to the arm of the player.

Tuning TMD-1 and TMD-2 is best achieved by measuring fl and £2 by accelerometer 404A and alter kl and k2 as needed. Changing ml and m2 is only warranted if changing kl and k2 cannot achieve the desired level of attenuation.

Squeezing on washer 402 increases kl and fl. Releasing pressure on it has the opposite effect. Moving either sleeve 405 out of mass 403 or shaft 406 out of sleeve 405, or doing both, decreases k2 and £2. Moving said parts in the opposite direction has the opposite effect. Fp is in the range of 30-240 Hz, while Fr is in the range of 180-240 Hz. That indicates more adjustment capacity for ml than for m2. The easiest way to add mass to ml is to screw a heavy threaded plug into mass 403 underneath electronics 404.

Electronics 404 can do the necessary measurements and calculations, suggesting stiffness or mass alterations as described. Alternatively, the measurements can be made in a lab for tuning only the racket itself. The same method as described above can be used to determine the weight and mounting method to tune just the racket as opposed to the system described above which tunes the racket both with respect to the racket itself and to the player. Attention is finally turned to FIG. 23, which by assembly 400, illustrates in isometric view of a tennis racket butt end high-range-weight socketed two-piece double-isolation button- end insert with built in telemetric accelerometer and turn button tuning capability, shown in Fig. 22 and Fig. 21 as a further preferable embodiment of the invention. Likewise elements are labeled identically. Socket 401 may have snap in protrusions and knob 403 may have angular turn indicating slots, dimples or other features, not shown for clarity.

Note that the rigid body metal prats, threaded into rubber parts prevents twisting off and thereby off tuning said masses. Also, that part 404 may have push button on-off switch, digital readouts, beeping warning sounds and other features, which are however non-essential to the preferred embodiment illustrated. Such telemetric accelerometers are becoming popular items on tennis rackets already.

The present invention is described above with reference to a preferred embodiment. However, those skilled in the art will recognize that changes and modifications may be made in the described embodiment without departing from the nature and scope of the present invention. For instance, receiving various material (say aluminum, stainless steel or bronze), thus various weight, but same size solid or hollow balls or ellipsoids or torus or rounded edge blocks in a snap-in semi-open or pop-in ball socket of tuned elasticity and/or damping, attached rigidly to the shaft end is considered obvious and thus hereby instructive over the teachings of this invention. Replacing the metallic mounting of columns and brushes with coil or leaf spring is also considered obvious and instructive.

Various further changes and modifications to the embodiment herein chosen for purposes of illustration will readily occur to those skilled in the art. To the extent that such modifications and variations do not depart from the spirit of the invention, they are intended to be included within the scope thereof.

Having fully described the invention in such clear and concise terms as to enable those skilled in the art to understand and practice the same, the invention claimed is:

Claims

1. An apparatus for mounting to the butt end of a handheld sporting device used to hit an object, the butt end having an X, Y, and Z axis, a rigid body mounted within a cavity, the body having a mounting parameter for each axis, the mounting parameter selected to tune the sporting device from the group of rigid, elastic, or attenuation material.

2. The apparatus as per claim 1, whereas said device is member of at least one of the following kind of sporting goods: tennis racket, racquetball racket, badminton racket; table tennis pad; baseball bat, softball bat, tee ball bat; golf club, polo club, cricket club and hockey club.

3. The apparatus as per claim 1, whereas said rigid body is located in one of the position in said device relative to its butt end: outside, inside and both sides.

4. The apparatus as per claim 1, whereas at least one of said rigid bodies weight falls in the percentage ranges of said device: 5%-25%.

5. The apparatus as per claim 1, whereas said insert is one of the following construction type: single body, dual body and multi body.

6. The apparatus as per claim 1, whereas said body has one of the predominant dynamic properties: essentially flexible with marginal damping, essentially flexible with moderate damping, essentially flexible with high damping, essentially compressible with high damping with marginal elasticity, and essentially compressible with high damping with no elasticity.

7. The apparatus as per claim 1, whereas said tuning is based on accelerometer

measurement made on built in accelerometer, rigidly coupled to at least one of said rigid bodies of said mass-dampers.

8. The apparatus as per claim 1, whereas said tuning comprises altering the stiffness of said flexible body by compression induced strain.

9. The apparatus as per claim 1, whereas said tuning comprises altering the stiffness of said flexible body by replacement.

10. The apparatus as per claim 1, whereas said tuning comprises altering the mass of said rigid body by replacement.

1 1. The apparatus as per claim 1, whereas said flexible body is replaced, at least temporarily by stiff body, in order to separate said Eigen frequencies for said tuning.

12. The apparatus as per claim 1, whereas said flexible body is replaced, at least temporarily by stiff body, in order to reduce the distance between said center of mass of said hitting devices and its gripping fulcrum.

13. A method of tuning a handheld sporting device, the method including the steps of:

determining the frequency of the device,

determining mass of an insert for attenuating the frequency of the device;

mounting the body within the butt end of the device.

14. The method of claim 13, whereas said insert is tuned with respect to dynamic response: orthotropic and unidirectional, bidirectional, tri-directional and uniform omnidirectional.

15. The method of claim 13, whereas said insert is mounted in respect to degree of freedom:

1-DOF and 2-DOF.

16. The method of claim 13, whereas said insert is one of the following kind in respect to tuning modes regarding the properties of said device: 1-st Eigen value, 2-nd Eigen value and 3-rd Eigen value.

17. The method of claim 13, wherein the tuning is made in respect the dynamic response to impacts being predominantly: under damped, critically damped and over damped.