CA2110220A1

CA2110220A1 - Games racket

Info

Publication number: CA2110220A1
Application number: CA002110220A
Authority: CA
Inventors: Michael Edward Curtis
Original assignee: Individual
Current assignee: Dunlop Ltd
Priority date: 1992-12-08
Filing date: 1993-11-29
Publication date: 1994-06-09
Also published as: MY131627A; DK134293D0; DK134293A; CN1089874A; DE4341686A1; GB9225731D0

Abstract

ABSTRACT
GAMES RACKET
A badminton racket with improved playing qualities is provided by including a modified joint where the shaft enters the handle. The flexibility of the shaft in a direction in a plane through its axis perpendicular to the plane of the strings is increased but is substantially unaffected in a direction in a plane through its axis parallel to the plane of the strings. This is achieved by anchoring the shaft through an elastic joint which is flexible in the direction perpendicular to the plane of the strings but substantially rigid in the direction parallel to the plane of the strings, whereby the shaft can pivot about the point where it enters the handle.

Description

l. 2 ~ 1~22~
GAMES RACKET
This disclosure relates to games rackets, particularly those incorporating a single shaft such as a badminton racket. Such a racket consists essentially of a head containing the strings attached to a handle by means of a single shaft. The overall stiffness of the shaft and the distribution of that stiffness along the length of the shaft affects the playing properties of the racket. This is because the bending and recovery of the shaft immediately prior to and during the action of striking the shuttlecock can influence the head speed of the racket as it strikes the shuttlecock, so that this can add to the overall speed of the racket head so leading to increased speed applied to the shuttlecock. Also, improved "feel"
can be provided to the player by this means which is desirable for the efficient striking of the shuttlecock and satisfaction to the player.
Increasing the flexibility of the shaft (measured in terms of the increased deflection of the tip of the racket when loaded at this point with the handle rigidly clamped) generally is desirable, but this often leads to shafts of poor durability. Also, this can be disadvantageous in that whilst increased flexibility in a plane through the axis of the shaft perpendicular to the plane of the strings is desirable, it is undesirable for flexibility to be increased in a plane through the axis of the shaft parallel to the plane of the strings, because this can lead to less chance of contact with the shuttlecock being made in the centre of the racket head.
According to the present invention a games racket comprises a head defining interlaced strings, a shaft and a handle, the shaft connected at a first end to the head and at a second opposite end to the handle, the handle having a central longitudinal axis wherein the shaft is attached within the handle substantially along said central axis by an anchorage means which ~1~0220

2.
substantially rigidly anchors the shaft in a direction in the plane of the interlaced strings whilst permitting under playing conditions elasticity to anchorage of the shaft in a perpendicular direction to the plane of interlaced strings so that the shaft is capable of pivoting in said perpendicular direction about the point where it enters said handle.
The invention relates to a method for attaching a shaft to a handle of a racket whereby its flexibllity is apparently increased in a direction in a plane through its axis perpendicular to the plane of the strings, whilst not increasing its flexibility in a plane through its axis parallel to the plane of the strings. This is achieved by a special way in which the shaft of the racket is anchored in the handle in which the anchorage allows a degree of elastic movement in one plane, but not in another. The elastic movement allows the shaft of the racket to rotate about a pivot where the shaft enters the handle so that this rotational movement is additive to flexure of the shaft under load. In other words, the deflection of the tip of the racket incorporating this anchorage system is the sum of the deflection, due to the bending of the shaft, and that due to rotation of the shaft about its pivot point as allowed by the elasticity of the anchorage system. The anchorage system, however, is substantially rigid in the perpendicular plane, so that the deflection of the tip of the racket is solely due to flexure of the shaft in this direccion. See Figures 1 to 4, in which:
Figure 1 is a schematic side view, i.e. in the plane of the strings, of a racket 10 in which a head portion 11 is attached to a shaft 12 which is attached to a handle 13 by means of an anchorage means l~a, positioned towards the butt end of the handle and an elastomeric grommet 15 at the point where the shaft enters ~
;, . . . .", 2l~n22a

3.
the handle. The anchorage means comprises a spring 14a which can move elastically in direction AA';
Figure 2 is a schematic front view of the same racket shown in Figure 1 and illustrates the anchorage means 146 which cannot move in direction BB';
Figure 3 illustrates schematically what happens when the racket head portion 11 is subjected to a load "L" as shown in Figure 1 such as from striking a shuttlecock. The spring 14a allows the shaft to move a distance "w" and the elastomeric grommet 15 allows the shaft to pivot thus giving a total deflection "w+d";
Figure 4 illustrates schematically what happens when the racket head portion 11 is subjected to a load "L" applied parallel to the plane of the head as shown in Figure 2. The substantially rigid anchorage in this plane prevents the end of the shaft from moving and the total deflection of the head portion is limited to "d", the result of pivotal movement about the grommet 15;
Figure 5 is a sectional schematic view, which would be in a plane perpendicular to the plane of the strings, of part of a games racket in which the shaft 16 is bonded into an anchorage means 17 consisting of a spring element 17 made of an elastomeric composition. The spring element 17 is provided with spigots 18, pairs of which engage into one of several pairs of holes 19 provided in the handle 20. The spring element 17 is designed so that in the ~'.' ' ' ' A ' ~ ' 211022~

4.
direction A-A' it is elastic but in the direction B-B' it is substantially rigid; and Figure 6 is a sectional view through the handle 20 of Figure 5 with the spring element anchorage means shown as an end view.
Figures 5 and 6 also show how longitudinal location of the shaft 16 is arranged by spigots 18 in the spring element 17 locating with pairs of holes 19 in the hollow handle 20. The position of the anchorage of the spring element can be adjusted longitudinally by moving the spigots into different pairs of holes and this can be arranged by increasing or decreasing the length of the shaft to provide an overall acceptable racket length. It will be appreciated that the apparent flexibility of the shaft in the plane through the shaft perpendicular to the strings can be significantly modified by this means.
It will be appreciated that the qualities of pivot point 21 are also an important factor. This may be made from the same material as that of the handle, or it may be formed of separate material which may itself have elastic properties. Preferably the pivotal point is flexible to prevent rattling during use of the racket, e.g. it may be of an elastomeric material in the form of a grommet.
The spring element may be of various configurations provided that the requirements of rigid location of the shaft in rotational sense and a longitudinal sense are achieved and lateral flexibility is only allowed in the desired plane. The material from which the spring element is made may be metal, rubber or plastic or a combination of these, or of other suitable material, the difference in rigidity properties (hardness and resilience) being due to the compositions/conformations of the materials from which the elements are formed.

Claims

5.
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A games racket comprises a head defining interlaced strings, a shaft and a handle, the shaft connected at a first end to the head and at a second opposite end to the handle, the handle having a central longitudinal axis wherein the shaft is attached within the handle substantially along said central axis by an anchorage means which substantially rigidly anchors the shaft in a direction in the plane of the interlaced strings whilst permitting under playing conditions elasticity to anchorage of the shaft in a perpendicular direction to the plane of interlaced strings so that the shaft is capable of pivoting in said perpendicular direction about the point where it enters said handle.

2. A games racket according to Claim 1 wherein the anchorage means comprises a spring element.

3. A games racket according to Claim 1 or 2 wherein the spring element comprises an elastomeric, plastic or metallic material.

4. A games racket according to Claim 1 or 2 wherein the shaft is bonded to the anchorage means.

5. A games racket according to Claim 1 or 2 wherein it is the configuration of the anchorage means which rigidly anchors the shaft in one direction and permits elasticity in another.

6. A games racket according to Claim 1 or 2 wherein the anchorage means substantially prevents rotational movement of the shaft in relation to the handle.

7. A games racket according to Claim 1 or 2 wherein the anchorage means is positioned adjacent the end of the handle distant from the head portion.

8. A games racket according to Claim 1 or 2 wherein at the point wherein the shaft enters the handle the shaft is held elastically in position by an elastomeric, plastic or metallic component (15).

9. A games racket according to Claim 1 or 2 wherein at the point where the shaft enters the handle the shaft is held elastically in position by a grommet.

6.

10. A games racket according to Claim 1 wherein the position of the anchorage means is adjustable along the central axis of the handle.

11. A games racket according to Claim 10 wherein the means to allow adjustment comprises complementary formations in the anchorage means and handle.