WO1994021332A1 - Corde de raquette de sport - Google Patents

Corde de raquette de sport Download PDF

Info

Publication number
WO1994021332A1
WO1994021332A1 PCT/GB1993/000547 GB9300547W WO9421332A1 WO 1994021332 A1 WO1994021332 A1 WO 1994021332A1 GB 9300547 W GB9300547 W GB 9300547W WO 9421332 A1 WO9421332 A1 WO 9421332A1
Authority
WO
WIPO (PCT)
Prior art keywords
racket
string
core
sleeve
jacket
Prior art date
Application number
PCT/GB1993/000547
Other languages
English (en)
Inventor
Daniel Elbaum
Ofer Karo
Original Assignee
Kosmin, Gerald, Emmanuel
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 Kosmin, Gerald, Emmanuel filed Critical Kosmin, Gerald, Emmanuel
Priority to AU37598/93A priority Critical patent/AU3759893A/en
Priority to PCT/GB1993/000547 priority patent/WO1994021332A1/fr
Publication of WO1994021332A1 publication Critical patent/WO1994021332A1/fr

Links

Classifications

    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B1/00—Constructional features of ropes or cables
    • D07B1/16—Ropes or cables with an enveloping sheathing or inlays of rubber or plastics
    • D07B1/162—Ropes or cables with an enveloping sheathing or inlays of rubber or plastics characterised by a plastic or rubber enveloping sheathing
    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B51/00—Stringing tennis, badminton or like rackets; Strings therefor; Maintenance of racket strings
    • A63B51/02—Strings; String substitutes; Products applied on strings, e.g. for protection against humidity or wear
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2201/00—Ropes or cables
    • D07B2201/20—Rope or cable components
    • D07B2201/2047—Cores
    • D07B2201/2052—Cores characterised by their structure
    • D07B2201/2055—Cores characterised by their structure comprising filaments or fibers
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2201/00—Ropes or cables
    • D07B2201/20—Rope or cable components
    • D07B2201/2083—Jackets or coverings
    • D07B2201/2087—Jackets or coverings being of the coated type
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2201/00—Ropes or cables
    • D07B2201/20—Rope or cable components
    • D07B2201/2083—Jackets or coverings
    • D07B2201/209—Jackets or coverings comprising braided structures

Definitions

  • SPORTS RACKET STRING This invention relates to strings for sports rackets used in ball games, such as tennis, squash, racketball, badminton and the like.
  • Racket string is traditionally made of animal gut, or synthetic plastics material. Strings differ in strength, elasticity, surface friction and other physical parameters.
  • a sports racket string is provided with an inner core of low durometer plastics material, a sleeve composed of a multiplicity of small diameter metal filaments, and a plastics material jacket which envelopes the core and sleeve, said jacket being made of plastics material with a higher durometer than the core.
  • the jacket utilising surface texture and material physical characteristics, grips and "envelopes" a portion of the ball surface allowing for greater contact area with the ball.
  • the jacket is further compressed in the contact area.
  • the sleeve tends to unwind its braided pattern upon impact of the striking ball.
  • the sleeve may be embedded in the inner core, to further limit inner core elongation at the specific contact area vicinity.
  • Compression-set of the composite string of the invention upon impact provides for mechanical fixation, known as friction joint, of strings at their crossing point, preventing movement and slipping of the strings relative to each other upon impact of a striking ball. Constant spacing of the strings is maintained, and all forces are evenly distributed within and around the ball contact area. As a result a better controllability of the ball at any contact location on the racket is achieved, and effectively a dynamic "sweet spot", covering the whole area of the racket face is provided.
  • Handling of the ball is highly dependent on core section shape and dimensions. Imparting speed, spinning momentum, and ease of ball direction control are all shape dependent. It is therefore possible to make rackets for various specific purposes with specially adjusted core section shapes and dimensions. It is further possible to make a two sided/double purpose racket allowing for priority characteristic to be controlled differently with opposite racket faces.
  • such a double purpose racket may be achieved by utilising a string with a core having a cross section in the shape of an isosceles triangle, with the base consistently facing the same side of the racket.
  • the triple layer structure of the string of the invention provides such a long life span, that wear of the jacket surface occurs earlier than string rupture. Therefore a colour coding index can be provided so that the exposure of a designated colour indicates a degree of loss of the surface characteristics, and an indication is given of the end of the useful life of the string.
  • the string may be constructed with more than one sleeve, more than one jacket or with additional sleeve and jacket pairs.
  • Figures 1A and 13 are cross-sections of two racket strings, botn made in accordance with the invention, each comprising a core 1, a sleeve 2 and a jacket 3;
  • Figure 2 is an exploded side view of a racket string made in accordance with the invention, showing a core 1, a braided sleeve 2 and a jacket 3;
  • Figure 3 illustrates alternative cross-sections of racket strings made in accordance with the invention.
  • the core 1 is made of a synthetic polymer strand having a designated cross section shape.
  • the core material properties of hardness, elasticity and tensile strength, provide for elongation and shrinkage upon impact to produce designated rebound force.
  • the core cross section shape and dimensions may be varied to achieve preferred effects on the imparted tennis ball.
  • the core is subject to elongation at the contact area of the striking ball and its close vicinity, as allowed by the sleeve.
  • the core is further subject to local deflection and compression as a result of the longitudal and diametric changes of the sleeve.
  • the hardness of the core material has a substantial effect on the strength, flexibility, and elongation.
  • Various degrees of hardness may be used with different models to achieve desired performance, with differing elongation and compression rates.
  • the core material is polyethylene, preferably having a hardness defined by SHORE D65.
  • the core material may be any suitable plastics or alloy plastics material selected from the thermo-plastics, thermo-setting plastics, elastomers, reactive plastics materials or natural materials, of any suitable hardness.
  • the shape of the core cross section is determined by the priority of controlling certain characteristics rather than others. Spinning the ball at desired speed, achieving higher speed, reducing shocks from incoming balls, and accurately redirecting imparted balls are all shape dependent.
  • the cross-section of the core may advantageously be made in six different shapes according to the higher priority characteristics associated with the different models, viz.
  • (f) diamond (f) diamond.
  • the cross-section may be V-shaped, pentagonal, hexagonal or any other suitable geometrical design.
  • the core may be either solid or hollow.
  • Figure 3 of the drawings illustrates these various cross- sections.
  • 1 shows a circular cross-section, 2 star- shaped, 3 square, 4 concaved square, 5 triangular, 6 concaved triangular, 7 isosceles triangular, 8 concaved isosceles triangular, 9 rectangular, 10 concaved rectangular, 11 diamond and 12 a concaved diamond cross- section.
  • the dimensions of the core cross-section provide means of determination of the decompression, elongation, and deflection of the core upon ball impact.
  • the cross-section dimension which governs the performance of the core is the largest in any direction.
  • this dimension may be the diameter of a circular cross-section such as shown in Figures 1A and IB, or it may be the longest line between any two corners of a iamond-shaped cross-section.
  • the core diameter or its largest dimension varies between 0.7-1.lmm for different string models.
  • the core diameter or its largest dimension may be any value within the range from 0.35mm to 1.35mm.
  • the sleeve 2 is made of small diameter filaments (fibres) which may be braided around the core as shown by way of example in Figure 2 or in accordance with any other pattern.
  • the strands may be arranged in groups as shown by way of example in Figure 13, or they may be evenly distributed as shown in Figure 1A, or arranged in accordance with any preferred design.
  • the sleeve is used as stability and tension control mechanism, applying its strength and flexibility to the string system.
  • the sleeve 2 is partially embedded in the core 1.
  • the sleeve 2 may be covering the core 1 and may be embedded into the jacket 3, or it may be completely embedded into the core 1, or it may be embedded in both the core 1 and the jacket 3.
  • the braided pattern of sleeve 2 in Figure 2 is subject to unwinding upon impact of the striking ball, whereby predictable elongation of the sleeve 2 is limited to the close vicinity of the contact area of the ball and strings, with virtually no elongation of the sleeve fibres.
  • the sleeve is further subject to decrease in diameter in the same contact area.
  • Deflection of the braided sleeve applies the main imparting force. While elongated and deflected, the braided sleeve applies compression to the core, enabling core decompression which provides the secondary imparting force.
  • the sleeve 2 acting as a stability and tension control mechanism and enhancing the strength of the string, provides for a greater string life span.
  • the sleeve threads pattern determines the flexibility and durability of the string.
  • the sleeve is constructed as a braid enveloping the core. Penetration of the sleeve threads into the core material can be up to 80%, preferably 15% of the sleeve thickness.
  • the sleeve pattern may be any mesh, or spiral pattern, with or without braiding.
  • the sleeve may not penetrate the core material at all or it may penetrate up to 80% of its thickness into the core material.
  • the sleeve threads may be arranged to provide only partial coverage of the core surface, so that surface coverage may vary, for example, between 5% and 95% of the core surface, preferably 20 to 60%.
  • the sleeve threads material is stainless steel alloy 304.
  • the sleeve material may be any ferrous or non-ferrous substance, or any metallic or non-metallic alloy.
  • the sleeve threads cross- section has a circular shape with a diameter of 0.04mm.
  • the sleeve threads may have other different shapes such as circular, diamond, square, etc.
  • the longest dimension (or diameter, if circular) of the thread cross-section may be between 0.0025-0.11mm. It will be appreciated by those versed in the art that the invention is not limited to the above described embodiments and many various modifications of the sleeve may be made.
  • the jacket 3 is a distinct structural element of the racket string serving as the direct means for applying to the imparted ball the forces and direction as generated by the player's arm, and enhanced by the core and the sleeve.
  • the jacket material surface characteristics enable a sufficiently firm and stable grip of the ball whereby the forces and their direction are applied with a high degree of efficiency.
  • the jacket material also allows for sufficient compression of the jacket 3 between the ball and the sleeve 2, to increase contact area with the ball and further improve the distribution of forces on the ball surface.
  • the hardness of the material has a substantial effect on the grip between the ball and the string.
  • Various degrees of hardness may be used with the different models to achieve desired performance.
  • the jacket material is polyurethane, of hardness defined by SHORE A60 and A85.
  • the jacket material may be any suitable polymeric material, or any plastics or alloy plastics material selected from the thermo-plastics, thermo- setting plastics, elastomers, reactive plastics materials, or natural materials of suitable durability and surface characteristics.
  • the compression set enabled by the respective materials and structure of the string layers results in mechanical fixation, known as friction joint, of the strings to each other at their crossing points upon impact preventing relative movement of the strings.
  • the jacket is composed of layers of various colours, wherein a colour coding system is utilised to indicate the wear of the outer jacket to a point where its physical characteristics are below the designated standards.
  • the colours applied to the inner strata of the jacket will become visible after a predicted portion of the jacket has been worn.
  • a colour coding index provided with the string allows a visual comparison with the governing colour of the tennis racket string to determine the remaining useful life of the string.
  • the cross-section shape and dimensions of the core determine effectiveness of imparting desired characteristics to the ball. Therefore, in accordance with a further aspect of the invention asymmetrical cross-section core shapes are used to construct: dual- purpose strings. It will be appreciated that rackets which impart characteristics of different degree and intensity to the ball at opposite faces of the racket may enable a better handling of the ball for desired shots. They also enable the player to surprise his/her opponent by imparting different shots with the same body movements.
  • strings would have to be applied to such rackets while maintaining the proper orientation relative to the racket plane.
  • an asymmetrical cross-section core is used and a groove or similar mark on the racket- handle or frame indicates to the player the orientation of the racket so that the sides may be alternated in accordance with the player's requirements.
  • Dual-purpose, double-sided strings and rackets may be marked by applying different colours on opposite sides of the racket's strings. The different colours on opposite sides of the string which is stranded properly on the racket give a clean indication to the player as to the side of the racket to be played.
  • colour coding also provides the player's opponent with information about the side-orientation of the racket so the impending shot can be appreciated and response planned.

Abstract

Une corde composite, destinée au cordage de raquettes de sports telles que des raquettes de tennis, comprend un noyau interne (1) composé de plastique, de préférence de polyéthylène, une gaine composée d'une pluralité de filaments de petit diamètre entourant le noyau (1), les filaments étant de préférence composés d'un alliage métallique tel que l'acier inoxydable, et une chemise externe (3) en plastique présentant une dureté mesurée au duromètre supérieure à celle du matériau composant le noyau. Pour un meilleur résultat, les filaments de la gaine (2) sont tressés autour du noyau (1), et peuvent être partiellement ou entièrement encastrés dans le noyau (1) ou dans la chemise (3).
PCT/GB1993/000547 1993-03-17 1993-03-17 Corde de raquette de sport WO1994021332A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU37598/93A AU3759893A (en) 1993-03-17 1993-03-17 Sports racket string
PCT/GB1993/000547 WO1994021332A1 (fr) 1993-03-17 1993-03-17 Corde de raquette de sport

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/GB1993/000547 WO1994021332A1 (fr) 1993-03-17 1993-03-17 Corde de raquette de sport

Publications (1)

Publication Number Publication Date
WO1994021332A1 true WO1994021332A1 (fr) 1994-09-29

Family

ID=10728628

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1993/000547 WO1994021332A1 (fr) 1993-03-17 1993-03-17 Corde de raquette de sport

Country Status (2)

Country Link
AU (1) AU3759893A (fr)
WO (1) WO1994021332A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2461100A (en) * 2008-06-20 2009-12-23 Yao I Fabric Co Ltd Sport racquet string with hollow portion

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2649833A (en) * 1949-04-14 1953-08-25 Ashaway Line & Twine Mfg Manufacture of lines for racquets
WO1981001797A1 (fr) * 1979-12-22 1981-07-09 A Cadonau Boyaux pour raquettes de tennis ou jeux analogues
FR2495477A1 (fr) * 1980-12-04 1982-06-11 Ireb Raquette de tennis
GB2167094A (en) * 1984-11-01 1986-05-21 Rucanor Bv String for sports racquets
WO1990008575A1 (fr) * 1989-02-03 1990-08-09 Sahatjian Ronald A Cordage de raquette de sport
WO1991011549A1 (fr) * 1990-01-26 1991-08-08 Chen Sam Hsin Shun Code a plusieurs aretes pour raquette

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2649833A (en) * 1949-04-14 1953-08-25 Ashaway Line & Twine Mfg Manufacture of lines for racquets
WO1981001797A1 (fr) * 1979-12-22 1981-07-09 A Cadonau Boyaux pour raquettes de tennis ou jeux analogues
FR2495477A1 (fr) * 1980-12-04 1982-06-11 Ireb Raquette de tennis
GB2167094A (en) * 1984-11-01 1986-05-21 Rucanor Bv String for sports racquets
WO1990008575A1 (fr) * 1989-02-03 1990-08-09 Sahatjian Ronald A Cordage de raquette de sport
WO1991011549A1 (fr) * 1990-01-26 1991-08-08 Chen Sam Hsin Shun Code a plusieurs aretes pour raquette

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2461100A (en) * 2008-06-20 2009-12-23 Yao I Fabric Co Ltd Sport racquet string with hollow portion

Also Published As

Publication number Publication date
AU3759893A (en) 1994-10-11

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