GB2186492A

GB2186492A - A badminton racket shaft and grip assembly

Info

Publication number: GB2186492A
Application number: GB08700876A
Authority: GB
Inventors: Takashi Fujita
Original assignee: Nippon Gakki Co Ltd
Current assignee: Nippon Gakki Co Ltd
Priority date: 1986-01-22
Filing date: 1987-01-15
Publication date: 1987-08-19
Also published as: JPS62119964U; GB8700876D0; JPH0342946Y2; GB2186492B

Abstract

A badminton racket shaft and grip assembly includes a tubular shaft (1) and a tubular grip shaft (2) extending from one end of the shaft (1) in axial alignment therewith, which grip shaft (2) gradually increases in diameter towards its tail end. An end cap (6) is fitted in the tail end of the shaft (2) and the shaft (2) is wholly covered by a synthetic resin cover (4). <IMAGE>

Description

SPECIFICATION A badminton racket shaft and grip assembly The present invention relates to a badminton racket, and more particularly a badminton racket shaft and grip assembly having atubularshaftandimproved flexure properties.

A conventional racket in general includes an oval head, a tubular shaft coupled at one end tote head via a connector and a grip coupled to the other end of thetubularshaft. Thetubularshaft is usually an elongated pipe made of metal orfiber reinforced plastic (FRP). The grip includes a wooden core inserted tightly overthe other end of the tubular shaft and provided with an axial bore receptive of a weight adjusting mass. An end cap is force inserted into the hole formed in the tail end ofthe wooden core.

With this conventional construction, the diameter ofthetubularshaft is smaller byfarthan thatofthe wooden core of the grip and the wooden core is highly rigid. Dueto thesefactors,the grip does not substantially flex when a ball is struck with the racket and the striking force is almost completely absorbed by elastic deformation of the tubular shaft only.

Such poorflexure ofthe grip limits the swing speed ofthe head at fast moving or shooting balls. In orderto remove this I imitation, the inventor of the present application has already proposed the production of a badminton racket having a tubular shaft one end of which extends over the entire length of the grip whilst gradually increasing in diametertowardsthetail end ofthegrip.

However, since the end cap is force inserted over the tail end ofthewooden core, grips ofdifferentdia- meters require use of end caps of different diameters. In addition, since the inner diameter of an end cap must be largerthan the outer diameter of an associated wooden core of the grip, increased size of the end cap undesirably increases the total weight of the badminton racket.

Ideally, the longitudinal axis ofthe tubular shaft should matchthatofthegripwhencoupledtogether.

Sincethetubularshaft and the grip are formed separately in the case of the above-described construction, it is difficult to attain such matching with high precision.

There is thus a need for an improved badminton racketshaftand grip assembly with a high degree of flexure of the grip and with high precision axial matching between the tubular shaft and the grip.

According to the present invention there is provided a badminton racket shaft and grip assembly, including a tubular shaft, a tubular grip shaft extending from one end ofthetubularshaft in axial alignment therewith, which grip shaft gradually increases in diameter towards its tail end remote from the tubular shaft, an end cap inserted into the tail end ofthe tubular grip shaft, and a synthetic resin coverwholly wrapping at leastthe tubular grip shaft.

For a better understanding of the present invention, and to show howthe same may be carried into effect, reference will now be made, by way of example, tothe accompanying drawings, in which: Figure lisa perspective view of a shaft and grip assembly for a badminton racket according to one embodiment ofthe present invention in a disassembled state, and Figure2 is a sectional side view of part of the prod uction processforthe assemblyshown in Figure 1.

One embodiment of a badminton racket shaft and grip assembly according to the present invention is shown in a disassembled state in Figure 1, in which a tubular grip shaft2 is coupled at one end to one end of a tubular shaft 1 made of, for exàmple, FRP. The tubular grip shaft 2 includes a cylindrical section 2a receptive of said one end ofthetubularshafti and an elongated conical section 2b which gradually increases in diametertowards the tail end ofthegrip shaft. An end cap 3 is securely inserted into the tail end of the conical section and the tubular shaft 2 is wholly wrapped with a synthetic resin cover4such as a urethane foam cover.

In one alternative, the tubular grip shaft 2 maybe formed in one piece with the tubular shaft 1.

The conical section 2b ofthe tubular grip shaft 2 is provided near its tail end with a pair of opposed radialthrough holes5forreceivingsetpins9forcorrect setting of the end cap 3 relative to the grip shaft 2.

The end cap 3 includes a hexagonal plate head 6, anannularsmallerdiameterflange7projectingsub- stantially perpendicularly from the rear face of the head 6 around the periphery of the latter and a hollowcylindrical part8 projecting substantially per pendicularly rearwardly from the rearface of the head 6 within the flange 7. Neartherearend,the cylindrical part8 is provided with the set pins 9 rad- ially projecting therefrom in opposite directions. On both sides of each set pin 9, a pair of longitudinal slots 8a are formed in the cylindrical part8 and opening through the rear end ofthe part 8.Thus a narrow section 8b is left between each pairofslots 8a and this narrow section 8b is abletoflex elastically in the radial direction of the cylindrical part 8. The part 8 is inserted into the tail end of the conical section 2b while flexing the narrow sections 8b towards the axis ofthe part 8. On removing the flexing force on the narrow sections 8b, the narrow sections 8b resume their original positions due to their own elasticity so that the set pins 9 fit into the associated radial through holes 5. Thus, the end cap 3 is set in position in the tail end of the tubular grip shaft 2.

After this coupling, the coupled components with a nose cap 10 are placed in a pair of moulds 11 and 12 as shown in Figure 2. At this placing, the periphery 7a oftheflange7 abuts the innerface ofthe moulds 11 and 1 2forcorrect positioning ofthe coupled components. Thereafter synthetic resin solution is introduced into the gap between the components and the moulds 11 and 12. On solidification,this resin forms a cover 4 around the components to complete the shaft and grip assembly.

The presence ofthe tubular section in the assumbly provides a badminton racket with high gripflexure,thereby enabling a quick swing of the head ofthe racket to be made. The synthetic resin cover can be formed at the correct position due to abutment of the end cap head with the mould when forming the cover. The cover 4 also covers the pro jecting ends ofthe pins 9 and assists in securing the endcap6totheshaft2.

Claims

1. A badminton racket shaft and grip assembly, including atubularshaft, atubulargrip shaftextending from one end of the tubular shaft in axial align menttherewith, which grip shaft graduallyincreases in diameter towards its tail end remote from the tubular shaft, an end cap inserted into the tail end of the tubular grip shaft, and a synthetic resin cover wholly wrapping at least the tubular grip shaft.

2. An assembly according to ciaim 1,wherein the end cap includes a head, an annular smaller diameterflange projecting substantially perpendicularly from the inside face of the head around the periphery ofthe head, a hollow cylindrical part projecting sub- stantially perpendicularly from the inside face of the head within the flange and at least one set pin projecting radiallyfrom the cylindrical part, wherein a pair of slots opening through the tail end of the cylindrical part are formed in the cylindrical part one on each side of the set pin leaving a narrow section in between, and wherein the tubular grip shaft is provided near its tail end with a radial through hole for receiving the set pin when the end cap is coupled to the tubular grip shaft.

3. A badminton racket shaft and grip assembly, substantially as herein before described with reference to the accompanying drawings.

4. A badminton racket including a shaft and grip assembly according to anyone of claims 1 to 3.