GB2279580A

GB2279580A - Shuttlecock

Info

Publication number: GB2279580A
Application number: GB9413909A
Authority: GB
Inventors: Peter Shu Chun Cheng
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-07-10
Filing date: 1994-07-11
Publication date: 1995-01-11
Also published as: GB9413909D0

Abstract

A plastic shuttlecock comprises a cap (10) and skirt (12) wherein the axially outermost part of the skirt is formed with circumferentially spaced radially outwardly extending wings (32). Each wing (32) includes a free edge (34) and an adjacent opening (36). The free edge (34) is inclined to the longitudinal axis of the shuttlecock at an angle between 30 DEG and 45 DEG . The provision of the wings (32) and openings (36) enable the shuttlecock to develop spin extremely readily even when struck gently by a badminton racket, the spin being developed by circumferentially acting air pressure components created by the provision of the inclined wings and openings. <IMAGE>

Description

TITLE: Shuttlecock This invention relates to a shuttlecock made of a plastics material and to its method of manufacture.

The use of plastics materials in the manufacture of shuttlecocks is now extremely widespread and plastics shuttlecocks have replaced the traditional feathered shuttlecocks at most levels of the game of badminton. A typical design of plastics shuttlecock has a skirt and cap wherein the skirt comprises a plurality of stems extending in circumferentially spaced apart relationship axially from the cap and radially outwardly of a central longitudinal axis of the shuttlecock i.e. the stems are contained within a notional conical surface. Typically such stems are interconnected between their extremities and a position intermediate the cap and such extremities by a lattice-work configuration of plastics material.Such a lattice is of generally conical shape but is convoluted to provide alternating axially extending peaks and valleys so that when the shuttlecock is viewed axially from the free end of the skirt it comprises a circumferentially extending series of undulations.

One of the disadvantages of a plastics shuttlecock is that it does not mimic accurately the flight characteristics of a feather shuttlecock. In particular plastics shuttlecocks do not readily develop spin during their flight although various proposals have been made to design plastics shuttlecocks which do spin readily. For example, it is proposed in GB-A-926049 for the axially extending stems of the skirt to be disposed helically. In GB-A-1 103 364 it is proposed to "weight" the lattice skirt by having more plastics material on one side of each valley of the skirt than on the other side thereof. In GB-A-2 059 271 it is proposed to crimp or flute the skirt between each adjacent pair of stems so that the crimping extends at an angle to the longitudinal axis of the shuttlecock.All of these proposals have the intent of providing some degree of spin to the shuttlecock during its flight.

In practice, plastics shuttlecocks which are commercially available do not spin very well during flight especially when struck gently. It is an object of the present invention to provide an improved plastics shuttlecock which will offer good flight characteristics and which will readily develop spin during its flight. It is also an object of the invention to provide an improved method of manufacturing such a plastics shuttlecock.

In accordance with one aspect of the invention there is provided a shuttlecock comprising a cap and a plastics skirt wherein the skirt includes a plurality of stems extending axially and radially from the cap at an angle to the longitudinal axis of the shuttlecock so as to be contained in or substantially contained in a notional conical surface, the stems being interconnected by a circumferential skirt portion including a plurality of circumferentially spaced apart wing portions each having a free edge projecting radially outwardly of said notional conical surface and being inclined to the longitudinal axis of the shuttlecock, and an opening being formed in the skirt portion adjacent a free edge of some at least of the wing portions.

The skirt portion, in axial end view of the shuttlecock, may be of undulating form providing alternating generally axially extending peaks and valleys with a said opening being formed in part of the valley adjacent a said free edge of a said wing portion. Alternatively the skirt portion need not be of undulating form but may be contained wholly in a notional conical surface from which the free edges of the said wing portions project radially outwardly.

Conveniently the skirt portion within which the wing portions and openings are formed is of perforated form. Said perforated form may comprise a lattice-like configuration providing a plurality of apertures defined between adjacent generally axially extending stem portions and generally circumferentially extending ring portions of the plastics material comprising the skirt portion. Such a perforated skirt portion may comprise the axially outermost part of the skirt, the skirt including also an axially inner part which may comprise an unperforated circumferentially extending part interconnecting said stem portions or may comprise a further plurality of generally circumferentially extending ring portions interconnecting the axially extending stem portions.

Each said wing portion conveniently extends from the axially outermost extremity of the skirt to a position intermediate said axially outermost extremity and the axially inner extremity of the skirt portion within which the wing portion is formed. Each said opening is conveniently of a configuration having one side defined by a said free edge of a said wing portion which is inclined to the longitudinal axis of the shuttlecock.

Conveniently each said wing portion is inclined at an angle of between 30 and 45" to the longitudinal axis of the shuttlecock.

Also in accordance with the invention there is provided a method of forming a plastics shuttlecock as described above by an injection moulding technique wherein the shuttlecock is formed between relatively axially movable male and female mould parts.

Other features of the invention will become apparent from the following description given herein solely by way of example with reference to the accompanying drawings wherein: Figure 1 is an end view of a shuttlecock constructed in accordance with the invention, the view being taken axially from the open end of the skirt of the shuttlecock with only part of the skirt construction being illustrated in full; Figure 2 is an underneath perspective view of the shuttlecock of Figure 1 with only part of the skirt being illustrated in full; Figure 3 is an end view taken axially from the open end of the skirt of an alternative embodiment of a shuttlecock in accordance with the invention; and Figure 4 is a side elevation of the shuttlecock of Figure 3.

The shuttlecock of the invention is of conventional generally conical overall configuration comprising a cap 10 for striking by a badminton racket and a skirt 12 extending axially and radially outwardly of the cap and being contained generally in a notional conical surface. In the embodiment illustrated in Figures 1 and 2 the skirt 12 comprises an array of main stems 14 equidistantly spaced apart circumferentially and being attached at their one ends to a centre boss portion 16 of the cap 10 and being interconnected at a position spaced axially away from the cap by a circumferentially continuous skirt portion.The skirt portion in this embodiment comprises two different configurations, an axially inner first part 18 thereof being unperforated and extending circumferentially of the stems 14 over an axial distance thereof to occupy approximately the middle one third of the axial extent of each stem. An axially outer second part 20 of the skirt portion is perforated and in this embodiment comprises a generally latticelike configuration having a plurality of axially extending intermediate stems 22 and circumferentially extending rings 24 to define a plurality of lattice apertures of generally square or rectangular configuration.

The stems 14 and all of the material of the skirt portion parts 18 and 20 together with the boss portion 16 of the cap are all formed integrally with one another of a plastics material by an injection moulding process. The boss portion 16 of the cap is covered with a foam plastics outer cover 26 of circular cross sectional form having a domed base as illustrated in Figure 2.

As illustrated in Figures 1 and 2 both parts 18 and 20 of the skirt portion are convoluted to provide a series of circumferentially alternating peaks 28 and valleys 30. Each peak 28 i.e. the radially outermost part of each undulation comprises part of one of the main stems 14 whereas each valley 30 i.e.

the radially innermost part of each undulation is defined between each adjacent pair of main stems 14. Each peak 28 and each valley 30 extends generally axially of the skirt of the shuttlecock so as each also to be contained within a notional conical surface.

As will be seen clearly from Figures 1 and 2 of the drawings, a plurality of radially outwardly extending wings 32 is provided in the axially outermost part 20 i.e. the lattice part of the skirt portion. In this embodiment the wings 32 are provided between alternating pairs of main stems 14. Each wing 32 includes a free edge 34 extending from the axially outermost extremity of a main stem 14 to a position adjacent the axially innermost part of the outer part 20 of the skirt portion at the next adjacent main stem 14. Each wing 32 projects a greater distance radially outwardly from the skirt at its axially outermost extremity so as to taper radially inwardly towards the axially innermost extremity of the outer part 20 of the skirt.An opening 36 is formed in the outer part 20 of the skirt portion in that valley side containing a wing end which lies between the adjacent main stem and the valley itself, the opening being of generally triangular form when viewed from the side as will be seen from the drawings.

The opening 36 is bounded by the aforesaid free edge 34 of a wing 32 and by a generally axially extending part 38 of the outer part 20 of the skirt portion adjacent a valley 30 thereof. Although not essential to the invention, there may be provided a circumferentially extending ring 40 comprising an axially outermost extremity of the skirt in which case such ring 40 provides a further boundary to each opening 36. The free edge 34 of each wing 32 extends at an angle to the longitudinal axis of the shuttlecock, the main stem 14 which merges into the free edge 34 also being formed to the same angle at a position intermediate the axially outermost and innermost extremities of the outer part 20 of the skirt portion.

Typically the angle of inclination of the free edge 34 of each wing 32 to the longitudinal axis of the shuttlecock is 45C although such angle may be selected to be between 30C and 45" to such axis.

As illustrated in this particular embodiment, the valley sides of the undulating lattice-like part 20 of the skirt portion are "weighted" in an alternating manner i.e. there is more material present in one valley side than in the other in each complete undulation. This weighting is provided by including a greater number of axially extending intermediate stems 22 within the one valley side than in the other so that in the weighted valley side the lattice perforations are generally rectangular whereas in the other valley side the lattice perforations are generally square.

An alternative embodiment of shuttlecock formed in accordance with the invention is illustrated in Figures 3 and 4 of the accompanying drawings wherein like reference numerals refer to like parts hereinbefore described with reference to Figures 1 and 2. In this embodiment an array of main stems 14 extend axially and radially outwardly of a cap 10 so as to lie in a notional conical surface. The stems 14 are equidistantly spaced apart circumferentially and are attached at their ends to a centre boss portion 16 of the cap 10. At a position spaced axially away from the cap 10 the stems 14 are interconnected by a circumferentially continuous skirt portion comprising an axially inner part 18 and an axially outer part 20.

Said inner part 18 comprises a plurality of axially extending circumferentially spaced apart secondary stem portions 42 and circumferentially extending axially spaced apart ring portions 44 interconnecting said stem portions 42. Said outer part 20 of the skirt portion also comprises a similar array of interconnected secondary stem portions 42 and ring portions 44. The stem portions 42 and ring portions 44 define a skirt portion which is contained wholly in a notional conical surface which does not comprise the undulating peaks and valleys of the embodiment described with reference to Figures 1 and 2.

In the axially outer part 20 of the skirt portion there are provided a plurality of circumferentially spaced apart wings 32 and openings 36. Each wing 32 may be configured in any suitable manner so as to provide a sufficient area of material to influence the spin characteristics of the shuttlecock. For example, each wing 32 may comprise perforated plastics material wherein the perforations may be a plurality of circular apertures, or each wing may be in the form of the lattice or mesh illustrated in the embodiment of Figures 1 and 2. Alternatively each wing 32 may comprise a plurality of inclined extensions of the ring portions 44.

Each wing 32 projects radially outwardly of the said notional conical surface and comprises a free edge 34 extending from the axially outer extremity of the skirt to a position axially inwardly displaced from such extremity. Each wing 32 projects a greater distance radially outwardly from the skirt at its axially outermost extremity so as to taper radially inwardly towards the axially innermost extremity of the said outer part 20 of the skirt portion. A said opening 36 is formed of generally triangular form when viewed from the side as will be seen from Figures 3 and 4 of the drawings, each opening being bounded by the aforesaid free edge 34 of a wing 32 and by a generally axially extending edge 46.

Optionally as illustrated, each opening 36 may additionally be bounded by an axially outermost one of the circumferential ring portions 44. The free edge 34 of each wing 32 extends at an angle to the longitudinal axis of the shuttlecock and typically the angle of inclination of such free edge 34 to the longitudinal axis of the shuttlecock is 450 although other angles may be found appropriate.

It is found in use that a shuttlecock constructed in accordance with the foregoing principles having wings 32 and openings 36 develops spin extremely readily when struck by a badminton racket. In particular the shuttlecock develops spin when struck gently. The development of spin is due to circumferentially acting air pressure components created by the provision of the inclined wings and the openings.

As mentioned above, a plastics shuttlecock in accordance with the invention may be produced by an injection moulding process. In such a process the shuttlecock is moulded from a thermoplastic material between two relatively axially movable mould halves comprising a female part of hollow generally conical form and a male punch part of generally conical form inserted within the female part during the moulding operation. The wings 32 and openings 36 of the shuttlecock of the invention are readily moulded by such male and female moulding parts which, after the moulding has been completed, are readily axially separable without damage to the moulded shuttlecock. The moulding channels defining the stems 14 and all of the parts 18 and 20 of the skirt portion are conveniently provided as corresponding grooves on the outer surface of the male part of the die, the interior surface of the female part of the die being generally smooth although as will be appreciated by those skilled in the art some or all of the moulding channels may be formed on the inner surface of the female part.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A shuttlecock comprising a cap and a plastics skirt wherein the skirt includes a plurality of stems extending axially and radially from the cap at an angle to the longitudinal axis of the shuttlecock so as to be contained in or substantially contained in a notional conical surface, the stems being interconnected by a circumferential skirt portion including a plurality of circumferentially spaced apart wing portions each having a free edge projecting radially outwardly of said notional conical surface and being inclined to the longitudinal axis of the shuttlecock, and an opening being formed in the skirt portion adjacent a free edge of some at least of the wing portions.

2. A shuttlecock as claimed in claim 1 wherein the skirt portion, in axial end view of the shuttlecock, is of undulating form providing alternating generally axially extending peaks and valleys with a said opening being formed in part of the valley adjacent a said free edge of a said wing portion.

3. A shuttlecock as claimed in claim 1 wherein the skirt portion of the shuttlecock is contained wholly in a notional conical surface from which the free edges of the said wing portions project radially outwardly.

4. A shuttlecock as claimed in any one of claims 1 to 3 wherein the skirt portion within which the wing portions and openings are formed is of perforated form.

5. A shuttlecock as claimed in claim 4 wherein said perforated form of the skirt portion comprises a lattice-like configuration providing a plurality of apertures defined between adjacent generally axially extending stem portions and generally circumferentially extending ring portions of the plastics material comprising the skirt portion.

6. A shuttlecock as claimed in claim 5 wherein a perforated skirt portion comprises the axially outermost part of the skirt, the skirt including also an axially inner part comprising an unperforated circumferentially extending part interconnecting said stem portions

7. A shuttlecock as claimed in claim 5 wherein a perforated skirt portion comprises the axially outermost part of the skirt, the skirt including also an axially inner part which comprises a further plurality of generally circumferentially extending ring portions interconnecting the axially extending stem portions.

8. A shuttlecock as claimed in any one of the preceding claims wherein each said wing portion extends from the axially outermost extremity of the skirt to a position intermediate said axially outermost extremity and the axially inner extremity of the skirt portion within which the wing portion is formed.

9. A shuttlecock as claimed in any one of the preceding claims wherein each said opening is conveniently of a configuration having one side defined by a said free edge of a said wing portion which is inclined to the longitudinal axis of the shuttlecock.

10. A shuttlecock as claimed in any one of the preceding claims wherein each said wing portion is inclined at an angle of between 300 and 450 to the longitudinal axis of the shuttlecock.

11. A shuttlecock constructed and arranged substantially as hereinbefore described with reference to any one of the accompanying drawings.

12. A method of forming a plastics shuttlecock as claimed in any one of the preceding claims by an injection moulding technique wherein the shuttlecock is formed between relatively axially movable male and female mould parts.

13. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.