Classifications

• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B59/00—Bats, rackets, or the like, not covered by groups A63B49/00 - A63B57/00
  • A63B59/40—Rackets or the like with flat striking surfaces for hitting a ball in the air, e.g. for table tennis
• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B2102/00—Application of clubs, bats, rackets or the like to the sporting activity ; particular sports involving the use of balls and clubs, bats, rackets, or the like
  • A63B2102/16—Table tennis

Definitions

• the present invention relates to table tennis, more familiarly known as ping-pong, including rackets used for the practice of the sport and racket head coverings that can hit the ball.
• a table tennis racket usually comprises a typing head, generally flat in shape with a rounded contour, to hit the ball, connected to a handle for the user to take the instrument.
• the head includes a soul called pallet formed of a plate of rigid material, such as wood in high-end rackets.
• the pallet is covered, on one side at least and most generally on each side, by an elastomeric coating, commonly called "sole”, packed on its entire surface with pins that are integrally formed in the material of the coating and generally comprise a drum that projects transversely from one side of the coating.
• the coated side of the pins is arranged on the outside of the pallet and directly performs the work of contact with the ball.
• the pins encountered by the ball bend elastically under the impact and cushion the impact to give the player better control of touching the ball.
• these pins store energy by deforming on impact and communicate to the ball a propulsion force additional to the return when they resume their shape.
• the studs of the coating are turned on the side of the pallet.
• the outer face of the racket head called to work with the ball, is constituted by the face of the coating or sole opposite the pins. It presents to the naked eye an essentially smooth appearance.
• a layer of low elastic material modulus of elasticity generally elastomeric foam, to which the coating is joined by gluing.
• the pins formed integrally in the coating material have a cylindrical shape.
• the connection between the body of the cylindrical pin and the solid plate is made in two different ways. Either it consists of a sharp angle profile (seen in section), in which the generatrix of the cylinder forms an angle of 90 ° with the flat surface of the coating which emanates the pin; either this connection is done by a softening of this angle made by deburring or a small frustoconical leave.
• the essential function of the pins is to give "rebound" to the ball by deforming the impact to help propel it back. They also participate by their lateral deformation to improve the lateral interactions between the ball and the racket and to increase their tangential adhesion to allow the player to communicate the effect to the ball and to control precisely the direction of return that he wishes to communicate . It is thus conceived that the work of the pins is translated in the long run by wear and fatigue of the material. In addition, in the case of strong forces, phenomena of fiambiting of the wall of the material appear in certain parts of the sole. These phenomena are likely to lead to the formation and spread of cracks in this material, which ultimately reduce the effectiveness of the racket until it becomes unfit for use.
• Japanese patent application JP2004113568A illustrates a frustoconical shape of pins in which the diameter of the pin decreases between its connection plane with the surface of the coating and its free end.
• the frustoconical shape stops at half height of the pin, distance from which the profile becomes cylindrical up to the free end face of the pin.
• a pin having a similar profile is also shown in the drawing of DE 102006034795 A1.
• EP1683552 is directed to a table tennis racket coating in which the contact surface with the ball, instead of having pins, is lined with adjacent cells and whose flexibility and contact with the ball go into a opposite to those which can be sought with pimples.
• the object of the present invention is to propose solutions for improving the performance of table tennis racket soles with pins, both in terms of the game itself and their durability. It also aims, according to a second aspect, the application of these solutions to a form of racket construction specifically geared towards the search for performance in the high-level game.
• a sole for the ball striking surface of a table tennis racket which comprises a flexible coating of elastic material, one side is lined with elastically deformable pins which project from said face.
• This sole is characterized in that the section transverse of said pins is greater in their zone of connection with this coating than in the zone near their opposite end and that the lateral surface of these pins has a concave curved profile on at least part of the height of the pin between these two zones .
• connection area of each pin on the surface of the elastic coating is devoid of any angular point with the flat surface of the coating.
• the profile of the lateral surface of the pins may also be devoid of angular point along its entire length. This avoids the creation of stress concentration zones untoward for the fatigue of the material and detrimental to the regularity of the reactions of the pins under deformation.
• the concave curved shape can be extended over the entire height of each pin up to the vicinity of their free end face.
• the gradual decrease in the section of the pins between their end of connection to the surface of the coating and their free end face as a result of such a profile provides a distribution of constraints favorable to a regular operation of the racket and its durability.
• the curved profile a radius of curvature which varies along this profile. It is preferred in this case that the smallest radius of curvature is provided at the connection area of the pin to the flat surface of the coating, and that the radius of curvature increases with the distance to the connection area up to a portion. the profile having the largest radius of curvature on the side of the free end of the pin.
• the curved profile can be obtained for example by the junction, preferably without angular points, of a succession of two or more circular arcs.
• a parabolic curved profile is provided and the applicants' tests have shown that this shape is particularly conducive to obtaining a good performance compromise for the racket coated with such a sole.
• the profile of the junction zone of the pin with the surface of the elastic coating is constituted by a half vertex of the parabola which is extended by the portion of the parabola whose radius of curvature is increasing towards the free end of the picot.
• the resistance and the good resistance of the pin system it is particularly advantageous for the resistance and the good resistance of the pin system to ensure that, in the connection area of the pins to the coating of the sole, the profile of each pin connects to the profile of the neighboring pins forming a continuous curved line without leaving a rectilinear or flat interval in the sole between the two pins, thus forming a continuous curved profile between each pin and its neighbour.
• the sole according to the invention finds a preferred application, characterized by an unexpected synergy of performance, in the case where the sole is mounted with the pimples turned towards the inside of the racket.
• the pins look towards the paddle which forms the soul of the racket, while the other face of the sole coating Remains essentially smooth, within the limits of brilliance allowed by the regulations that govern the game of ping-pong.
• This smooth face is facing outward and is the striking face of the ball.
• the gap between the elastic coating and the material of the pallet is occupied by a layer of a highly elastic material with a low modulus of elasticity compared to that of the elastic coating of the sole.
• This layer is currently very generally made by an elastomer foam and the free ends of the pins are directly applied and fixed to the foam, typically by gluing.
• the invention relates to a table tennis racket comprising a striking head and a handle connected to this head, the striking head comprising a pallet covered on one side at least by a sole formed by a flexible coating of elastic material, one side is provided with resiliently deformable pins which project from said face.
• This racket is characterized in that the face lined with pins of said sole is, in known manner, rotated on the inner side of the pallet such that the free ends of the pins are applied against a layer of a resilient elastic material the pallet whose modulus of elasticity is substantially smaller than that of the resilient coating of the sole.
• the cross-section of said pins is greater in their zone of connection with the coating than in the zone near their opposite end and the lateral surface of this pin has a concave curved profile over at least part of the distance between them. two areas.
• the sole according to the invention allowed to obtain a much better adhesion between the racket and the ball, or ball grip, than in models of known type, which is accompanied by a higher punching power.
• the wear resistance, especially in the striking surface is also improved and the cracking phenomena are greatly reduced or delayed if not eliminated.
• the applicants were able to observe that thanks to the curved shape of the side of the pins, the contact pressure of the ball on the racket at each impact is generally lowered and standardized. Instead of abruptly moving from a maximum value behind a pin to a very low value in places where the inner face of the coating is not supported, the contact pressure gradually decreases from the center of each pin to its edge. .
• the proposed provisions also provide a reduction of cracking primers and their propagation. These qualities are in addition to the benefits previously reported for the best buckling resistance. The best distribution of effort and the slower wear allow the high level player to maintain a consistent level of performance with his racket throughout the duration of a game.
• the profile of the junction zone of the pin with the surface of the elastic coating is constituted by a half vertex of the parabola which is extended by the portion of the parabola whose radius of curvature is increasing towards the free end of the picot. It is also preferred to conform the pins so that, in the zone of connection to the sole, the profile of each pin fits the profile of the neighboring pin following a continuous curved line without rectilinear or flat interval in a plane passing through the axes of the two pins.
• FIG. 1A shows a table tennis racket of the state of the art, the construction of which is particularly adapted to the implementation of the invention
• FIG. 1B shows a partial section in FIG. thickness of the racket of figure IA.
• Figure 2 shows a section enlarged with respect to that of Figure IB which shows the work of the components of the racket in the vicinity of its surface when it hits a ping pong ball with a certain vigor.
• Figure 3 illustrates a sectional view in which the surface components of the racket are in accordance with one embodiment of the invention, just before their deformation by the impact with a ping-pong ball.
• Figure 4 is a perspective view from below of a racket sole, whose contact face with the ball is smooth and which has pins in accordance with another embodiment of the invention.
• FIG. 1A shows a table tennis racket 10 conventionally comprising a generally rounded striking head 12 mounted at the end of a handle.
• the head 12 is a sandwich structure which comprises a core or pallet 17 formed here by a rigid central plate of wood. On the outer side, the head 12 has on each of its outer faces a flange 15 flat face for striking the ball. This face has been identified by the reference 15-1 for the soleplate 15 disposed on one side of the pallet. Reference 15-2 designates the striking face of the soleplate 15 placed on the other side of the pallet 17, as shown in FIG. 1B.
• Each sole 15 consists of a coating of elastic material 18 whose face opposite to the striking face 15-1, 15-2 is entirely lined with pins 20 which project transversely from the inner side of the sole towards the pallet 17.
• Each pin has, in this conventional example in the state of the art, a cylindrical body 21, one end 22 is connected to the flat inner surface of the coating 18 in a junction line here circular.
• the other end 24 of said pin 20 is free and comes into contact with the upper surface of an elastic foam layer 26 whose opposite or lower surface is secured to a face 17-1 of the pallet 17.
• the other face 17 -2 of the pallet 17 is similarly coated with a layer of elastic foam 26 in contact with the ends of the pins 20 on one side of the coating 18 of the other sole 15, the smooth face opposite the pins forms the face of strike 15-2.
• the density and distribution of spikes are regulated and allow the coating to lean back but without sagging against the spikes during contact with the ball.
• the foam layer 26 is constituted for example by a closed-cell latex.
• the modulus of elastic rigidity (or modulus of elasticity) of this foam is substantially lower than that of the material constituting the skin or flexible and elastically deformable coating 18.
• Figure 2 illustrates with a high magnification the deformation of the upper face 15-1 of the insole 15 with cylindrical pins 20, as shown in Figure IA and IB, during an impact with a ping ball.
• -pong 30 conventionally constituted by a thin celluloid shell of 40 millimeters in diameter. It is verified that the external face 15-1 of the coating 18 adopts a curved profile corresponding to the circumference of the ball 30 which communicates with the foam 26. It is also known that the The surface of this type of ball is relatively hard compared to the elastomer coating. It is manufactured in accordance with the rules of the game of table tennis and the technological possibilities of manufacture.
• the outer surface usually has surface roughness which it momentarily print the mark or the imprint on the surface of the outer coating 18 of the sole 15 during impact.
• the active face 15-1 of smooth appearance of the coating 18 is itself provided by microroughness manufacturing according to a standard of the game of table tennis intended to limit the brightness and avoid parasitic phenomena dazzle players .
• the micro-inequalities of this face are deformed and come "meshing" with the harsher ones of the ball 30.
• a strongly adherent dynamic contact or grip, in the sport language
• Figure 2 illustrates another phenomenon in the behavior of the racket 10 vis-à-vis the ball 30. Indeed, under the violence of the initial impact and the power of the shot of return of the ball, either in an almost normal direction, or with a frictional force created by a tangential component of the return force, the coating film 18 backed by the pins 20 elastically flexes and deforms them.
• the deformation is exerted in pure compression along the axis of the pin or in flexion as is well illustrated by the representation of FIG. 2. It will be noted that if the ends 24 of pins 20 are in contact with the foam 26 of the elastic layer, the intervals 32 between pins are not filled with foam. This leaves the pins with the ability to deform without encountering any resistance from their environment, either in width under the effect of a pure compression, or laterally in flexion.
• FIG. 3 shows a structure of the sole according to one embodiment of the invention.
• the striking head 112 comprises a rigid blade formed by a central plate 115 covered on each side with a layer of low-modulus elastic foam 126.
• An elastic coating 118 with a modulus higher than that of the foam 126 is glued to this layer.
• ci by the end faces of the pins 120 which cover its surface facing the support plate 115 and form a sole adapted to the ball striking.
• the body 121 of each pin 120 is integrally formed in the constituent material of the coating 118. It is connected to the internal face 135 of the coating 118 by an end 122.
• the cross section of this end 122 which constitutes the connection area with the The face 135 of the coating 118 is substantially larger than the section of its free opposite end end 124.
• the longitudinal profile of the wall 125 of the pin body 121 which connects these two ends is composed of two circular arcs of radii R1 and R2, with R1, on the side of the end 124, greater than R2, which makes the connection of the side wall 125 of the pin with the lower or internal face 135 of the coating 118.
• R1 and R2 are joined without angular point.
• the circular arc radius R2 is merged with the flat bottom surface 135 of the flexible coating 118. It may be noted that a flat part subsists in this lower surface between the connecting circles of neighboring pins 122.
• FIG. 4 represents in perspective, seen from below, a preferred embodiment of the invention, in particular for a competition racket, in which the outer elastic covering 218 of a sole 215 of pinned racket head turned. inward, has a smooth outer face 215-1 for contact with the ball 30. It is lined on its other side 235 with a network of pins which project from the inner side to the pallet not shown here, with a parabolic longitudinal section profile 225. At the connection with the face 235 of the coating 218, the longitudinal profile of each pin ends at the top 236 of the half parabola which constitutes this profile.
• the term longitudinal profile is used to describe the shape of the section of the wall of a pin by a plane passing through a longitudinal axis of the pin.
• Applicants have carried out tests on the following different embodiments of the pins and their attachment to the surface of the sole: a) cylindrical pins without connection profile; b) frustoconical connection at 45 °; c) connection by a rounded profile of small radius (less than 20% of the height of the pin); d) connection by a circular arc of relatively large radius (greater than 40% of the pin height; e) connection by a profile formed by the junction of two arcs of different radii of curvature; and f) parabolic profile picot.
• solutions b) and c) provided only a slight or negligible increase of the adhesion to the results obtained with solution a).
• solutions d) to f) all provide an appreciable increase in adhesion, the solution f) being characterized by an efficiency superior to that of the other two in all the aforementioned fields.

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• 2008
  • 2008-12-19 FR FR0858813A patent/FR2940131B1/fr not_active Expired - Fee Related
• 2009
  • 2009-12-16 JP JP2011541204A patent/JP2012511981A/ja active Pending
  • 2009-12-16 CN CN2009801511656A patent/CN102256671B/zh not_active Expired - Fee Related
  • 2009-12-16 WO PCT/EP2009/009045 patent/WO2010069560A1/fr not_active Ceased
  • 2009-12-16 US US13/141,074 patent/US8371969B2/en not_active Expired - Fee Related
  • 2009-12-16 EP EP09799032A patent/EP2384231A1/fr not_active Withdrawn

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