GB2458361A

GB2458361A - Shuttlecock

Info

Publication number: GB2458361A
Application number: GB0903379A
Authority: GB
Inventors: Gordon Willis
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-03-19
Filing date: 2009-02-27
Publication date: 2009-09-23
Also published as: GB0903379D0; GB0805091D0

Abstract

A badminton shuttle comprises a base 11 and a plastics conical skirt 18. The skirt 18 comprises, at its narrower end adjacent the base 11, a stem portion (10, figure 1) formed of a plurality of longitudinally extending stems 16 and, at its wide end, a flight portion (14, figure 1) within which a web 18 extends between the individual stems 16 to increase the aerodynamic drag on the shuttle. The skirt 18 includes a plurality of circumferentially extending annular ribs 20, 22 or 24 interconnecting the stems 16 both in the stem portion (10) and in the flight portion (14), the cross section of which ribs is dished or angled to increase the resistance of the annular rib to radial deformation.

Description

SHUTTLECOCK

Field of the invention

The invention relates to badminton shuttlecocks.

Background of the invention

A shuttlecock, herein also termed a shuttle for short, is a projectile that is used in the sport of badminton having the shape of an open cone with a high aerodynamic drag. The cone is traditionally formed of a number of overlapping goose feathers embedded into a rounded cork base which is covered with thin fabric. The shape of a shuttle makes it extremely stable aerodynamically and regardless of its initial orientation, it will turn to fly base first and remain in the base first orientation during flight.

The feathers of a traditional shuttle are not very durable. As a result, shuttles may need to be replaced several times during a single game. For this reason, synthetic shuttles have been developed that replace the feathers with a plastics skirt. The part of the skirt near the base, herein termed the stem portion, consists of a plurality of longitudinal stems emulating the shafts of feathers. These stems are connected to one another at the wider end of the skirt by a web or mesh which emulates the air resistance of the vane portions of feathers, this portion of the skirt remote from the base being herein termed the flight portion.

Plastics shuttles are far more durable, typically lasting several games without significant impairment to their performance.

Because they are significantly more economical, many players and clubs prefer to play with plastics shuttles.

However, the playing characteristics of feather shuttles and the existing plastics shuttles are quite different. In particular, the skirt of a plastics shuttle will tend to fold if the shuttle is hit very powerfully. Once the skirt has folded, the aerodynamic drag on the shuttle is greatly reduced. Consequently, skilled players can hit plastics shuttles extremely fast with relative ease. This changes the nature of the game because, amongst skilled players, the use of plastics shuttles will favour power players over players who place more reliance on delicate shots, which place the shuttle more accurately in a part of the court which cannot be reached by the opponent.

Most experienced and skilful players greatly prefer feather shuttles, while serious tournaments and leagues are almost invariably played using feather shuttles. In Asia, where feather shuttles are more affordable, plastics shuttles are hardly ever used by serious players, though this may have been affected by the outbreak of bird flu, which has pushed up the price of feather shuttles.

The aim of the present invention is therefore to improve plastics shuttles so that their performance may approximate more closely to that of feather shuttles.

In existing one piece plastics shuttles the main stiffening elements of the designs are the longitudinal stems that emulate the rigid quill or shaft sections of each feather in a feather shuttle. However, because the weight of the stems must be minimised and because they have a solid cross section, they provide far less rigidity than the hollow shafts of feathers to deformation in a radial direction.

It is known to mould one or more annular ribs to connect the solid stems in a generally circumferential manner. The skirt is conventionally formed as a one-piece injection moulding, and this places limitations on the shape these annular ribs if they are not to interfere with the extraction of the skirts from their mould at the completion of the moulding process. This in turn can affect the rigidity of the ribs and their performance in resisting the collapse of the skirt of the shuttle.

Object of the invention The present invention therefore seeks to provide a shuttle construction in which the circumferential reinforcing ribs can provide adequate stiffening of the skirt in the radial direction without having to resort to moulds with substantial undercuts calling for the use of collapsible cores nor to a two-part design as proposed by the Applicant in W02008/038040.

Summary of the invention

According to the present invention, there is provided a shuttle having a base and a plastics conical skirt, the skirt comprising, at its narrower end adjacent the base, a stem portion formed of a plurality of longitudinally extending stems and, at its wide end, a flight portion within which a web extends between the individual stems to increase the aerodynamic drag on the shuttle, wherein the skirt comprises circumferentially extending annular ribs interconnecting the stems both in the stem portion and in the flight portion and the cross section of each annular rib is dished or angled to increase the resistance of the annular rib to radial deformation.

If its cross section is angled, each annular rib preferably includes a first planar portion lying in a plane normal to the axis of the shuttle and a second cylindrical or conical portion upstanding from a perimeter of the planar portion.

If desired, at least one of the annular ribs may be formed with an undercut that permits the shuttle to be jumped off the core of the mould in which the shuttle is formed.

For reasons well known in the art, it is desirable for a shuttle to be designed so that it spins about its own axis as it moves through the air. Feather shuttles automatically benefit from this advantage on account of the mutually inclined individual feathers. It is not however easy to achieve the same effect with a plastics shuttle.

In a preferred embodiment of the invention, the web extending between at least some pairs of adjacent stems in the flight portion is formed with a facet defined by a fold line that extends from the rim of the flight portion to a point on one of the two stems lying nearer to the base of the shuttle, each facet forming an obstruction to air flow in a plane inclined to the axis of the shuttle, so as to impart a torque to cause the shuttle to rotate about its own axis during flight.

Each of the facets may be the smaller of two facets defined by two fold lines that extend from the rim of the flight portion to the same stem, the second facet offering a lesser resistance to air flow by virtue of its geometry, being inclined further away from the flow of air over the outer surface of the shuttle.

Brief description of the drawings

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which:-Figure 1 is an isometric view of a shuttle, Figure 2 is a schematic axial section through the shuttle of Figure 1, Figures 3 and 4 show suitable alternative constructions of the rib within the circle C in Figure 2, Figure 5 shows a suitable construction of the rib within the circle B in Figure 2, and Figures 6 and 7 show suitable alternative constructions of the rib within the circle A in Figure 2.

Detailed description of the preferred embodiment(s) Figure 1 shows an isometric view of the plastics conical skirt of a shuttle of the invention. The skirt has a stem portion 10 with a plug 12 at its narrower end for receiving a base (designated 11 in Figure 2) and a flight portion 14. The skirt has stems 16 that extend over its entire length, or at least a substantial part of its length, to emulate the shafts or quills in a feather shuttle. Within the flight portion only, a reticulated web 18 extends between the stems 16 to emulate the vane portions of a feather shuttle. It should be mentioned that it is not essential for the web to be reticulated.

The web 18 does not extend between the stems 16 in the stem portion 10 of the shuttle so that air can pass between the stems freely. To stiffen this portion of the stems 16 against deflection in a radial direction, they can be connected to one another by one or more annular reinforcing rib(s) 20 shown in section in Figure 2. Figure 6 shows the same rib 20 drawn to an enlarged scale. The rib 20 has an annular portion 20a that lies in a plane normal to the axis of the shuttle and a cylindrical portion 20b which is parallel to the axis of the shuttle.

An alternative to the design of Figure 6 is shown in Figure 7 where the first portion 20a' lies slightly out of the plane normal to the shuttle axis.

A second reinforcing annular rib 22 is positioned in the plane at which the stem portion 10 meets the flight portion 14. This rib is also shown in Figure 2 and to an enlarge scale in Figure 5. The rib is once again formed in two portions, namely a first portion 22a lying in a plane normal to the shuttle axis and a second conical portion 22b that extends at the same conical angle as the stems 16.

A third annular reinforcing rib 24 interconnects the stems 16 within the flight portion 14 of the shuttle. This rib cannot clearly be seen in Figure 2 but it is shown to an enlarged scale in Figure 3. The rib in this case is formed of a first planar annular portion 24a and a second cylindrical portion 24b connected to the inner perimeter of the planar portion 24a, both portions 24a and 24b merging into the web. The alternative construction shown in Figure 4 differs from that of Figure 3 in that the cylindrical portion 24b' is joined to the outer perimeter of the planar annular portion 24a' and extends in the opposite direction.

The reinforcing ribs 20, 22 and 24 at the different locations along the length of the shuttle differ from one another because the stems 16 taper in their thickness.

It will be noted that none of the ribs 20, 22 and 24 is formed as a substantial undercut and accordingly they can all be formed without using collapsible cores. It is possible to add rigidity by using a plurality of ribs with undercuts that can be "jumped" off a non-collapsible core.

It should be mentioned that undercuts have been used near the base of the shuttle to ensure that the moulding is held on the core half of the tool before ejection but these undercuts do not add to the rigidity of the stem and flight sections in the effective area.

Instead of the reinforcement ribs being angled as described above, it will be appreciated that resistance to deformation of the ribs can be increased by making them dished. Thus, for example in Figures 3 and 4, the angled ribs can be replaced by ribs having one portion of curved crescent-like cross-section that is concave outwards or concave inwards.

It will be noted in Figure 1 that the web 18 is formed with two facets 30 and 32 between each pair of stems 16.

These facets are formed by bending the web 18 inwards away from the conical outer plane of the shuttle. The facets 30 and 32 are defined by two fold lines. The first fold line 34 extends from the end of stem 16 to a point 36 on the adjacent stem nearer the base 11. The other fold line 38 extends from the same point 36 to a point 40 on the edge of the web between the two stems 16.

The two facets 30 and 32 of the embodiment shown in the drawing are of unequal size. The smaller facet 32 has no holes in it but the larger facet 30 is reticulated, as is the remainder of the web. The air flowing over the outer surface of the shuttle when it is in flight impacts the smaller facets 30, which has the effect of making the shuttle spin about its own axis. The other facets 32 are inclined further away from the flow of air and therefore they do not impact the air passing over the shuttle and they do not impart any significant torque to the shuttle in the opposite direction.

As is known in the prior art, the degree of spin can be modified by suitably reticulating the two facets. The embodiment illustrated maximises spin by having solid webs in the facets 30 and holes in the facets 32. As is standard, this will impart a clockwise rotation to the shuttle when viewed from its base.

Claims

CLPIMS1. A shuttle having a base and a plastics conical skirt, the skirt comprising, at its narrower end adjacent the base, a stem portion formed of a plurality of longitudinally extending stems and, at its wide end, a flight portion within which a web extends between the individual stems to increase the aerodynamic drag on the shuttle, wherein the skirt comprises circumferentially extending annular ribs interconnecting the stems both in the stem portion and in the flight portion and the cross section of each annular rib is dished or angled to increase the resistance of the annular rib to radial deformation.
2. A shuttle as claimed in claim 1 in which each angled annular rib has a first planar portion lying generally in a plane normal to the axis of the shuttle and a second cylindrical or conical portion upstanding from a perimeter of the planar portion.
3. A shuttle as claimed in claim 1, wherein the shuttle is injection moulded and at least one of the annular ribs is formed with an undercut that permits the shuttle to be jumped off the core of the mould in which the shuttle is formed.
4. A shuttle as claimed in any one of the preceding claims, wherein the web extending between at least some pairs of adjacent stems in the flight portion is formed with a facet defined by a fold line that extends from the rim of the flight portion to a point on one of the two stems lying nearer to the base of the shuttle, each facet forming an obstruction to air flow in a plane inclined to the axis of the shuttle, so as to impart a torque to cause the shuttle to rotate about its own axis during flight.
5. A shuttle as claimed in claim 4, wherein each of the facets is one of two facets defined by two fold lines that extend from the rim of the flight portion to the same stem, the second facet offering a lesser resistance to air flow.
6. A shuttle constructed substantially as herejnbefore described with reference to and as illustrated in the accompanying drawings.