EP0032506B1 - Raquette de tennis - Google Patents

Raquette de tennis Download PDF

Info

Publication number
EP0032506B1
EP0032506B1 EP80901593A EP80901593A EP0032506B1 EP 0032506 B1 EP0032506 B1 EP 0032506B1 EP 80901593 A EP80901593 A EP 80901593A EP 80901593 A EP80901593 A EP 80901593A EP 0032506 B1 EP0032506 B1 EP 0032506B1
Authority
EP
European Patent Office
Prior art keywords
racket
weights
ball
head
vibration
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP80901593A
Other languages
German (de)
English (en)
Other versions
EP0032506A1 (fr
EP0032506A4 (fr
Inventor
Simon Arieh
Jean-Pierre Budliger
Guy Courvoisier
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Battelle Development Corp
Original Assignee
Battelle Development Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Battelle Development Corp filed Critical Battelle Development Corp
Publication of EP0032506A1 publication Critical patent/EP0032506A1/fr
Publication of EP0032506A4 publication Critical patent/EP0032506A4/fr
Application granted granted Critical
Publication of EP0032506B1 publication Critical patent/EP0032506B1/fr
Expired legal-status Critical Current

Links

Images

Classifications

    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B60/00—Details or accessories of golf clubs, bats, rackets or the like
    • A63B60/54—Details or accessories of golf clubs, bats, rackets or the like with means for damping vibrations

Definitions

  • the present invention concerns a tennis racket having an increased moment of inertia around the racket handle axis and improved means for damping the vibration of the racket caused by off-center impact.
  • U.S. Patent 3,907,292 concerns a tennis racket the rim and the handle of which are surrounded by a tubular organ containing a series of fly-weights which normally rest in the throat portions of the tube due to the action of helical springs. Under use, the weights move toward the head of the racket because of the centrifugal force resulting from the racket swinging motion during play and increase the "sweet spot" of the stringed area; this also ensures a better bouncing control on the ball and an increased hitting power.
  • U.S. Patent 3,941,380 (Lacoste) discloses a tennis racket in which the head oscillations are dampled by means of a secondary oscillator working along the handle axis thereof at vibration antinodes. Since the oscillating bodies are located on the longitudinal axis of the racket, they do not affect the center of percussion and do not reduce the torque around the axis which results from an off-centered impact.
  • U.S. Patent 4,057,250 discloses means to generate a reactive force for diminishing the bouncing of the racket after ball impact.
  • masses producing the force must be able to move as freely as possible and, in this connection, the masses can even consist of loose metal shot.
  • the device is not a secondary oscillator.
  • the effect is distinguishable from the present invention since the increase of the moment of inertia of the racket in Kuban will only take place when the body has reached the end of its free elastic displacement which may be too late after the impact for being effective to increase the center of percussion. Moreover no damping of vibration is contemplated by an oscillator.
  • French Patent 2,387,670 concerns a golf club, the head of which is provided with balancing weights which can vibrate in a direction perpendicular to the longitudinal axis of said head. This oscillating motion ensures that the orientation of the head is maintained during the interval starting from the moment the ball is hit by the head to the moment it loses contact therewith after being hit.
  • the balacing weights increase the moment of inertia of the club in relationship to the hitting point of the head.
  • these weights have first a static effect because they increase the club inertia and, second, they have a dynamic effect because they move in a direction perpendicular to the hitting plane of the head.
  • Such displacements generate moments of inertia around the striking point which are substantially equal and enable the head to stay properly oriented after striking the ball, this action being effective for the full distance where the head and the ball stay in contact.
  • the object of the present invention is to increase the moment of inertia and the area of the "sweet spot" or center of percussion both longitudinally and transversely on a tennis racket to increase a players chance of striking the center, and at the same time to ensure the damping of the oscillation of the racket when the ball is nevertheless struck off-center.
  • the invention provides a tennis racket having movable or dynamic weights attached to the rim of the racket's head on both sides relative to the handle of the racket between the racket throat and the transverse axis of the head.
  • the position of these weights increases the moment of inertia around both the longitudinal and transverse axes of the racket effectively enlarging the sweet spot or center of percussion in all directions.
  • the moveable weights are coupled to said rim by elastic means whereby they can oscillate in a direction substantially perpendicular to the plane of the racket head with an intrinsic frequency 1.4-2 times that of the fundamental frequency of oscillation of the racket itself.
  • This arrangement provides an unique weighting system chosen in a manner such that when the system consisting of the moveable weights and the elastic means is driven into vibration at the frequency 1.4-2 times that of the racket, the weights complete the first half of their cycle and apparently restore energy to the racket before the ball leaves the racket. Moreover, the moveable weights with this critical frequency improve the angular stability of the racket over fixed weights or dynamic weights without the critical frequency.
  • Figure 1 shows a conventional tennis racket 1 comprising the head 2, the strings 3 attached to the head 2 and two side members 4 and 5 forming the throat of the racket connecting the head to the handle (not pictured).
  • the longitudinal and transverse axes are along lines 20, and 20 t respectively.
  • the racket comprises six moveable weights 6, consisting in this example of small cylinders of about 3g each, which are coupled to the head 2 by means of straps 7.
  • the straps 7 consist of energy absorbent polyurethane or equivalent elastomer, 1 mm thick, glued at the top of the arcuate section of each strap on the underside thereof to the frame. These straps 7 constitute elastic means for allowing movement of the weights generally perpendicular to the plane of the racket head.
  • the system composed of the straps and the moveable weights has an intrinsic oscillatory frequency and constitutes, with the racket itself, a two-section oscillator chain, each oscillator starting to vibrate with its own independent oscillating frequency whenever a ball impacts the racket strings 3.
  • the straps and/or the weights are made of energy absorbent materials which may aid the damping of the racket vibration in addition to the attenuating effect of the oscillator chain.
  • the moveable weights have multiple effects.
  • the first effect of the weights 6 is to increase the moment of inertia of the racket around both the longitudinal and transverse axes of the racket and to increase the angular stability to an off-centered impact of a ball on the racket.
  • Static weights would have a similar effect in increasing the effective size of the center of percussion, popularly known as the "sweet spot" of the racket, but the moveable weights, with the critical frequency, improve the angular stability over static weights as shown in Figure 6.
  • the ordinate of the graph in Figure 6 is the ratio of the angular rotation for moveable weights over that for static weights.
  • the abscissa shows the ratio of the intrinsic frequency of the weight system to the fundamental frequency of the racket. This analytical curve shows that over the frequency range of about 1.3-2 and also above 2.7, the angular stability is up to about 3% better with moveable weights than fixed weights. We believe that between 1.3 and 1.4 and above 2.7 the angular stability is improved, but these ranges are not ideal based on the other properties discussed later.
  • the additional weights be as light as possible relative to the racket so as not to impose an additional burden on the player.
  • the weights make a total of about 20 g.
  • the location of the weights must also be optimized in connection with the center of gravity and the moment of inertia of the racket. Placement of the weights as far as possible away from the longitudinal axis would maximize the moment of inertia but would require a larger compensating weight in the handle to retain the center of gravity at about point C in Figure 1, thereby increasing the total weight of the racket. Placement nearest the throat would require minimal compensating weight but would not have much effect on the sweet spot in the transverse directions.
  • a compromise is preferably struck, according to the invention, by symmetrically locating the weights on the rim at angles between about 30 and 70 degrees from the longitudinal axis on both sides thereof between the transverse axis and the throat. This position also has the advantage that the sweet spot of the racket is elongated in both the longitudinal and the transverse directions of the racket thereby increasing the possibility of a good return of a tennis ball.
  • the second and third effects of the weights are to damp racket vibration after impact and to restore a small but significant portion of the impact energy to the racket while the ball is still in contact.
  • the reason for the energy restoration is complicated and not easily explained.
  • the absolute values of the amplitudes A, and A 2 related to a two-section oscillator chain system are related to the impact excitation frequency Q as schematically represented on the diagram of Figure 2.
  • the magnitudes of the amplitudes A, and A 2 correlate with the amplitudes of the vibration of the racket and of the displacement of the weights 6, respectively.
  • the oscillation period T 1 of the racket was measured by means of a strain gauge placed on a sample racket and was found to be 0.01 sec.
  • the spring constant c 2 must be between about 235 g (force)/mm and 485 g (force)/mm to ensure damping and restoration of energy to the racket prior to the impacting ball leaving the racket.
  • Weights 6 and straps 7 having the properties determined above were divided into two groups, each group of three weights being located symmetrically on one side of the longitudinal axis of the reacket such as shown in Figure 1, at an angle of about 45° to the longitudinal axis.
  • Various experiments and measurements have been performed on this racket. Firstly, comparative measurements have been effected on two identical rackets, one of them being provided with the added weights of the invention, the other being unmodified. Vibration damping coefficients on both rackets were measured.
  • Figure 3 represents two diagrams, "a” and “b", of the damping of the vibrations, curve “a” corresponding to the control racket without the weights and curve “b” corresponding to the racket equipped with two groups of ten gram weights (three 3 g weights held by a 1 g strap). It can be seen that the damping rate of "b” is much faster than "a” as impact energy is transmitted to the moveable weights and the energy absorbing materials and then has been partially restored to the racket on the first cycle of the weights.
  • racket "b” provided a better control of the ball especially in the case of overspin of sliced balls, i.e. when the surface of the racket is at a non- orthogonal angle with the path of the incoming ball.
  • the half period of vibration of the added weights corresponds to about 60-70% of the contact time of the ball and the racket during the impact. Consequently, we have found that, as the weights move to the opposite side of the racket relative to the ball, energy temporarily stored in the moving weights is restored to the racket when the ball is still touching the strings. And the contact time is increased leading to better ball control. Moreover, after impact, the inventive weight system attenuates the vibration better than fixed weights and only slightly less effectively than moveable weights having frequencies equal to the fundamental mode of vibration of the racket.
  • FIG. 4 and Figure 5 illustrates a racket embodiment according to the invention in which the weights and the suspending elastic means are incorporated within the frame of the head. Suitable absorbent materials can be used in their construction.
  • This frame which is somewhat enlarged to accommodate the weights and springs, comprises three tubular housings 8 the axis of which are perpendicular to the plane of the head.
  • the stringing holes 9 are distributed in this area of the frame between the housings 8.
  • Each housing 8 is adapted for accommodating one of the weights, which are in the form of small cylinders 10, for example weighing 3 g, and having each an annular groove 10a in their side wall.
  • the cylindrical weights 10 are mounted axially within a helical spring 11, the end winding of which is crimped around the groove 10a and the first winding of which is set to a general base plate 12 by means of two strips 13 stamped in said plate 12.
  • the assembly of the three weights 10 and the springs 11 is assembled by putting each weight into its tubular housing 8, the base plate being inserted in a hollow area (not visible) located at one end of said housings 8.
  • Another identical plate (not shown) is inserted in another similar hollow area 14 of the other side of said housings.

Landscapes

  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Physical Education & Sports Medicine (AREA)
  • Golf Clubs (AREA)
  • Vibration Prevention Devices (AREA)
  • Vibration Dampers (AREA)

Abstract

Une raquette de tennis comprend des poids dynamiques (6) repartis symetriquement par rapport a l'axe longitudinal de la raquette entre le coeur de la raquette et l'axe transversal de la tete et suspendus par des bandes arquees (7) collees sur le cadre de la raquette (2) les poids pouvant se deplacer suivant une direction perpendiculaire au plan de la zone cordee (3). La combinaison des poids et des bandes est concue pour avoir une frequence de vibration propre d'environ 1,4 a 2 fois la frequence de vibration fondamentale de la raquette, de telle sorte que lorsque les poids vibrent a leur frequence propre (sous l'action d'une balle frappant dans la raquette), la vibration de la raquette est amortie par le transfert d'energie vers les poids, cependant de l'energie retourne aussi a la raquette par reaction dans le sens de la trajectoire de la balle avant que celle-ci ne quitte la raquette. La stabilite angulaire de la raquette est amelioree soit par des poids fixes soit par poids dynamiques ayant des frequences a l'exterieur de la plage critique.

Claims (5)

1. Raquette de tennis comprenant un cadre (2) de panier, un étranglement (4, 5) un manche et un cordage 3 tendu à travers le cadre 2 et comprenant des poids (6, 10) faisant partie du cadre (2) et destinés à élargir le centre de percussion dans le plan du cordage (3) et à absorber tout d'abord l'énergie de choc de la balle et ainsi amortir les vibrations dues au choc sur la raquette puis à restituer à la raquette au moins une partie de l'énergie de choc absorbée tandis que la balle est encore en contact avec les cordes (3), caractérisée par le fait que les poids (6, 10) sont reliés au cadre (2) de la raquette par des moyens élastiques (7, 11) placés des deux côtés de l'axe longitudinal (201) du cadre (2) et entre la gorge (4, 5) de la raquette et l'axe transversal (20t) du panier (2), ces moyens élastiques (7, 11) ayant des propriétés tellés que les poids (6, 10) oscillent dans une direction substantiellement perpendiculaire au plan du cordage (3) avec une fréquence de base d'environ 1,4 à 2 fois celle du premier mode de vibration de la raquette.
2. Raquette de tennis suivant la revendication 1, caractérisée par le fait que les poids (6, 10) sont reliés au cadre à des emplacements disposés symétriquement par rapport à l'axe longitudinal (201).
3. Raquette de tennis suivant la revendication 2, caractérisée par le fait que le total des poids placés de chaque côté de l'axe longitudinal est égal en grandeur.
4. Raquette de tennis suivant la revendication 1, caractérisée par le fait que le panier comprend des trous de guidage (8) ménagés à travers le cadre du panier perpendiculairement au cordage et par le fait que les moyens élastiques sont des ressorts (11) et que ceux-ci et les poids (10) sont logés dans les trous de guidage (8).
5. Raquette de tennis suivant la revendication 1, caractérisée par le fait que les moyens élastiques sont des arceaux (7).
EP80901593A 1979-07-26 1981-02-09 Raquette de tennis Expired EP0032506B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US6105279A 1979-07-26 1979-07-26
US61052 1987-06-10

Publications (3)

Publication Number Publication Date
EP0032506A1 EP0032506A1 (fr) 1981-07-29
EP0032506A4 EP0032506A4 (fr) 1982-05-26
EP0032506B1 true EP0032506B1 (fr) 1984-03-28

Family

ID=22033325

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80901593A Expired EP0032506B1 (fr) 1979-07-26 1981-02-09 Raquette de tennis

Country Status (6)

Country Link
EP (1) EP0032506B1 (fr)
JP (1) JPS56500955A (fr)
CA (1) CA1140608A (fr)
DE (1) DE3067259D1 (fr)
IE (1) IE49957B1 (fr)
WO (1) WO1981000214A1 (fr)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0166561B1 (fr) * 1984-06-22 1988-08-24 Dunlop Limited Raquette de sport
US5098098A (en) * 1988-07-07 1992-03-24 Petralia John W Shock and vibration absorbant sports racket
US5039097A (en) * 1990-04-12 1991-08-13 Bartlett William L Snap-on weight for a tennis racket
JPH09506787A (ja) * 1993-08-05 1997-07-08 ゴッドフリイ デガリス、ケニス ゲーム用ラケットのカウンターウエイトバランスシステム
US5599018A (en) * 1994-03-31 1997-02-04 Radel; Harry Strung racket
FR2751235B1 (fr) * 1996-05-07 1998-10-09 Bianchi Jean Claude Dispositif anti-vibration pour cadre de raquette de jeu de balle
GB2334894A (en) * 1998-03-04 1999-09-08 Dunlop Slazenger Group Ltd Mounting weights on games rackets
JP4615674B2 (ja) * 2000-05-29 2011-01-19 Ｓｒｉスポーツ株式会社 ラケットフレーム
EP2036594A1 (fr) * 2007-09-12 2009-03-18 Yuan Min An Enterprise Co., Ltd. Raquette multifunction

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1526734A (en) * 1923-04-04 1925-02-17 Frederick B Andrews Tennis racket
US2823037A (en) * 1956-02-16 1958-02-11 Ferte Louis G La Vibratory impulse generator for golf club
US3801099A (en) * 1971-06-23 1974-04-02 J Lair Tennis racquet
US3907292A (en) * 1972-02-05 1975-09-23 James P Moreland Dynamically variable tennis racket
US3941380A (en) * 1972-07-31 1976-03-02 Patentex S.A. Tennis rackets and similar implements with vibration damper
US4057250A (en) * 1975-09-05 1977-11-08 Kuban William G Tennis racket construction
DE2554267A1 (de) * 1975-12-03 1977-06-16 Kuebler & Co Schlaeger fuer tennis o.dgl. spiele
FR2352220A1 (fr) * 1976-05-21 1977-12-16 Malnar Leon Procede d'amortissement des vibrations d'une structure a ame creuse et raquettes de jeu mettant en oeuvre ledit procede
JPS53131133A (en) * 1977-04-21 1978-11-15 Zenzou Yamamoto Golf club

Also Published As

Publication number Publication date
EP0032506A1 (fr) 1981-07-29
CA1140608A (fr) 1983-02-01
EP0032506A4 (fr) 1982-05-26
DE3067259D1 (en) 1984-05-03
JPS56500955A (fr) 1981-07-16
IE49957B1 (en) 1986-01-22
WO1981000214A1 (fr) 1981-02-05
IE801541L (en) 1981-01-26

Similar Documents

Publication Publication Date Title
US4353551A (en) Tennis racket with frame mounted oscillatable weights
US6033324A (en) Vibration damping device for stringed racquets
US4165071A (en) Tennis racket
US5772541A (en) Vibration dampened hand-held implements
US4660832A (en) Shock and vibration absorbent handle
USRE31419E (en) Tennis racket
US4291574A (en) Tennis racket
US6077178A (en) Striking implement
CA1106867A (fr) Suppresseur des vibrations des cordes d'une raquette
US5613916A (en) Sports equipment for ball game having an improved attenuation of oscillations and kick-back pulses and an increased striking force and process for manufacturing it
US7178428B2 (en) Impact instrument
US4690405A (en) Tennis racket
EP0032506B1 (fr) Raquette de tennis
JPH09248357A (ja) 運動用具および野球バット
US4057250A (en) Tennis racket construction
CA1250329A (fr) Amortisseur de vibrations pour raquette de sport
US6293878B1 (en) Tennis racket with vibration damping member
US6203454B1 (en) Multi-mode vibration absorbing device for implements
US4333650A (en) String load apportioned racket
US6863628B1 (en) Vibration damping striking implement
NO173686B (no) Tennisracket
US4634124A (en) Vibration damped sports racquet
US5022651A (en) Exercise and training tensioning device for sporting racquets
USRE33372E (en) Tennis racket
Nathan et al. The physics of the trampoline effect in baseball and softball bats

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19810325

AK Designated contracting states

Designated state(s): CH DE FR GB NL SE

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): CH DE FR GB LI NL SE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19840328

Ref country code: NL

Effective date: 19840328

REF Corresponds to:

Ref document number: 3067259

Country of ref document: DE

Date of ref document: 19840503

ET Fr: translation filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19840713

Year of fee payment: 5

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 19840727

Year of fee payment: 5

NLV1 Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19840927

Year of fee payment: 5

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Effective date: 19850731

Ref country code: CH

Effective date: 19850731

GBPC Gb: european patent ceased through non-payment of renewal fee
REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19860328

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19860402

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19881118