WO1993020907A1

WO1993020907A1 - Improvements in shuttlecocks

Info

Publication number: WO1993020907A1
Application number: PCT/GB1993/000744
Authority: WO
Inventors: Roy William Buckland
Original assignee: Roy William Buckland
Priority date: 1992-04-08
Filing date: 1993-04-08
Publication date: 1993-10-28
Also published as: AU3900793A; CN1086451A

Abstract

A shuttlecock (501) for playing badminton comprises a base (510) and a flight section where the base includes a thin-walled nose portion (514) to be struck during play. The nose portion can be defined as thin-walled if the average wall thickness is less than or substantially equal to one tenth the diameter of the substantially hemispherical nose portion. Additionally a shuttlecock for playing badminton comprises a base (510), an array of feathers, a feather support (550) which is connected to the feathers and determines the radial extent of the feathers, and an adjustment device (580) which is connected to the feather support and the base and which enables relative movement of the feather support with respect to the feathers thereby enabling the configuration of the array of feathers to be altered.

Description

IMPROVEMENTS IN SHUTTLECOCKS

The invention relates to a badminton shuttlecock.

Badminton shuttlecocks comprise a dome shaped base portion which includes the surface to be struck by a racket while a game is in progress. Known shuttlecocks generally have substantially solid bases made for example from cork, foamed plastics material or rubber-like plastics. The base has a rounded nose, or hemi¬ spherical nose portion, which is elongated by a cylindrical extension to form a U-shaped base when viewed in cross-section. Shuttlecocks also comprise a flight-section which is joined to the base. The flights are either a single moulded plastics cage or a multiplicity of natural feathers joined in a frusto-conical array. In many cases it is known simply to drill holes in the top of the base and insert the stems of the feathers or ends of the flight section into the holes. This has the disadvantage of weakening a cork base. The base and flights can be held together by gluing. It is known to attach a flight section to the base by means of cooperative threaded elements associated with each.

Known shuttlecock bases have several disadvantageous features including; inconsistency of density of material; inconsistent strength to weight ratio; relatively high cost of manufacture; complexity of manufacture (such as the need for gluing); and the limitation of sources of supply of materials.

Of the existing shuttlecocks the majority have a solid base made substantially of cork. This material needs to be machined to the dome shape previously described and also drilled to allov; for insertion of the flight section. A further manufacturing step is to glue the flight section to the base.

Alternatively, it is known to make shuttlecock bases from rubber- type material or foamed plastics material. However, foam moulding has a relatively long cycle time and it is difficult to maintain consistency with foamed bases since the process is inherently variable. This gives rise to voids in the material which causes inconsistency of density. Similarly, since cork is a natural material its density varies, giving rise to variation in the response of shuttlecocks which may be reflected in a variation of flight speed from one shuttlecock to another. There is therefore a significant quality control problem in the manufacture of both cork and man-made bases.

An additional problem is that of supply of cork which is limited to certain regions (e.g. Portugal). The cork required must be of a certain low density for shuttlecock bases, hence the potential sourcing problem.

Whilst cork of the right density has a suitable weight to strength ratio for use in shuttlecocks it is not possible to match these properties in known bases made of synthetic materials. Hence, such bases tend to be heavier and/or weaker and the performance of shuttlecocks having such bases is markedly different from those having a cork base. Accordingly, there is much consumer resistance to shuttlecocks with artificial bases.

It is also known to provide shuttlecocks having a flight adjustment device which enables the flight characteristic of a shuttlecock to be varied. Such a shuttlecock is disclosed in EP0157547B1. One of the advantages of that shuttlecock is that it allows the flight characteristics of the shuttlecock to be altered after manufacture. Thus, to a certain extent, a known flight adjustable shuttlecock can tolerate the inconsistency of flight characteristic created by mass manufacturing processes and variable playing conditions such as variation in ambient temperature.

The invention seeks to avoid or at least mitigate some or all of these and other problems of the prior art and, in particular, to simplify manufacture and to reduce costs. One aspect of the present invention provides a shuttlecock comprising a base and a flight section wherein the base comprises a thin-walled nose oortion. In a prefered form of this aspect of the invention the thin- walled nose portion can be made from in ection-moulded thermoplastic and is substantially hemi-spherical in shape. The nose portion can be attached to a cylindrical section to form a substantially U-shaped base in cross-section.

A preferred feature of the shuttlecock base according to the invention is that the thin-walled base may have a thickness less than or substantially equal to one tenth the diameter of the nose portion.

Another preferred feature of the invention provides a shuttlecock wherein the nose portion has a total volume defined by the outer periphery of the nose portion and encompassing all material and untrapped space within the periphery wherein the volume of untrapped space is greater than or equal to half the total volume.

A further preferred feature provides that the nose portion has internal structural members which can reinforce the nose portion and/or connect the nose portion to the cylindrical section of the base.

Another preferred feature of this aspect of the invention provides that the cylindrical section and flight section comprise cooperative interlocking means. In an embodiment the means may be screw-threaded and enable relative axial movement of the flight section to the base thereby to effect variation in the outer diameter of the flight section. The means also allow the base and flight section to be readily engaged and disengaged.

Beneficially these features of the invention each enable a shuttlecock base to be manufactured more easily and with a greater consistency of performance characteristics compared to the known art. The base can be made by injection moulding plastics which is a much quicker process than foam moulding. Injection moulding also enables a large range of structural properties of the base to be varied such as density of material and geometry of internal struts. This enables a range of shuttlecocks with different elastic properties to be made; that is having different responses to being hit by a racket. This technique also gives greater consistency in mass production once the shuttlecock characteristics are chosen, unlike the variability of properties of bases made of foamed plastics for example.

Other benefits include; ease of assembly of components, cheapness of manufacture, avoidance of sourcing problems, variation of engineering/structural properties with little weight penalty, and quicker overall manufacturing time.

A further aspect of the invention provides a method of making a shuttlecock having a base and a flight section wherein the base comprises a thin-walled nose portionmade by injection moulding a suitable thermoplastics material.

Another aspect of the invention provides a base for a shuttlecock for playing badminton which base comprises a thin-walled nose portion.

A further aspect of the invention provides a shuttlecock which comprises a base, an array of feathers, a feather support which is connected to the feathers and determines the radial extent of the feathers, and an adjustment device which is connected to the feather support and the base and which enables relative movement of the feather support with respect to the feathers thereby enabling the configuration of the array of feathers to be altered.

Beneficially a shuttlecock according to this aspect of the invention enables the feather configuration to be altered thereby enabling the flight speed (or characteristic) to be altered after manufacture. This is advantageous since it allows fine tuning of such shuttlecocks and can mitigate the problems of inconsistency of flight characteristic due to the manufacturing process or playing conditions such as variation in ambient remperature.

In an embodiment of a shuttlecock according to this aspect of the invention the feather support is moved axially relative to the feathers by altering a separate adjustment device. The feathers have a fixed axial position relative to the base and the feather support causes the radial extent -of the feathers to increase or decrease according to the relative axial position of the feather support.

A preferred feature of a shuttlecock according to this aspect of the invention is that the feather support comprises a ring having an array of apertures through which feather stems pass. The feather support further comprises a lower boss or collar which is connected to the ring by means of struts. The feather support is relatively rigid so that it is able to exert sufficient force on the feathers to alter their radial position. Another preferred feature is that the adjustment device is rotatably connected to the collar of the feather support and that the adjustment device and base comprise cooperating threaded means. Thus, rotation of the adjustment device into the base causes axial movement of the feather support relative to the base and feathers but does not cause rotation of the feather support. In this preferred embodiment the feathers may have a fixed axial position relative to the base and can be supported therein in a biased position by biasing means. The biasing means may provide that the array of feathers has a large radial extent and therefore the feather support acts to exert an inward radial force thereon. Alternatively, the feathers may be biased in an array having a relatively small radial extent and the feather support may act against the bias, attempting to force the feathers to a larger radial position.

The invention will now be described, by way of example only, _ . reference to the accompanying drawings, in which: FIGURE 1 shows a sectional side elevation view of a first embodiment of a base for a shuttlecock according to the invention;

FIGURE 2 shows a side elevation view of a second embodiment of a shuttlecock according to the invention;

FIGURE 3 shows a side elevation view of a third embodiment of a shuttlecock according to the invention;

FIGURE 4 shows a partially sectional view of a base for a fourth embodiment of a shuttlecock according to the invention; and

FIGURE 5 shows a fifth embodiment of the invention in a side elevation cross-sectional view.

Figure 6 shows a sectional side elevation view of a sixth embodiment of a shuttlecock according to the invention.

The shuttlecock base 10 shown in Figure 1 comprises a nose portion 14 and cylindrical section 16. The nose portion 14 is hemi-spherical and shown in cross-section- The nose portion 14 in this example is hollow and has a thin walled outer periphery. It also comprises a connector means 18 which is used to connect the nose portion 14 to cylindrical portion 16. Cylindrical portion 16 has a cooperative connector means 20 which together with connector 18 form a tight interference fit thereby securing nose portion and cylindrical section together. The cylindrical section 16 further comprises internal screw-threading 22 which is used to connect the base to a cooperative threaded portion of the flight section of a shuttlecock. The cylindrical section 16 further comprises a recess portion 24 which can receive the ends of the feather stems in the flight section.

The simple rebate connector 16 and 18 between nose portion 14 and cylinderical portion 16 shown in- Figure 1 provides the benefit that the two portions can be easilv made, for example bv injection moulding, and then pushed together and glued.

Figure 2 shows a shuttlecock 101 which comprises base portion 110 and flight section 112. The flight section 112 has a conventional mesh structure 130, which is made of injection moulded plastics, and struts 132 connected to a nylon skirt 134 at their lower end. In this example the base section 110 is a single unit which can be made, for example, of injection moulded plastics to form a U-shaped device in cross-section comprising nose portion 114. Alternatively the base 110 may be formed by pressing a vacuum moulding for example. The base 110 and flight section 112 are joined by inserting the skirt 134 into the open cylindrical end of base 110 where the skirt is retained by ribs 122 formed on the inside of the base. The shuttlecock 101 may also comprise a thin outer covering to base 110 such as conventional fabric covering. Also, the open cylindrical end of the base 110 can be reinforced to retain the flight section by creating additional tension at the open end for example by wrapping tape around it, similar to a conventional lute.

Figure 3 shows a similar shuttlecock 201 to that shown in Figure 2 except that flight section 212 is made from sixteen natural feathers 231 such as goose or duck feathers. The feathers 231 are formed in a frusto-conical array by means of upper ring 235 and lower ring 236. The rings 235 and 236 can be threads wound around the feather structure and glued to hold the feathers in place.

The base 210 is formed of a hollow shell comprising nose portion 214 and cylindrical section 216. The base 210 further comprises connector component 222 which can be a cylindrical block of natural or synthetic material into which is drilled sixteen holes to receive the ends of the stems of feathers 231. The feather stems can be glued in position.

Alternatively the feathers may be held by a cage element ( such as feather support 450 or 550 shown in Figures 5 and 6), where the cage is fixedly connected to the base 210 in the finished shuttlecock rather than moveable relative thereto as in the example described in relation to Figures 5 and 6. This particular construction means that a shuttlecock can be made comprising natural feathers and only two injection moulded portions, namely a base 210 and a cage similar to support 550. Of course a fixed cage similar to support 550 could be used together with the other types of bases described herein, such as bases 10 or 110 for example.

A further shuttlecock base 310 is shown in Figure 4. The base 310 is similar to that shown in Figure 1 in that it comprises two separable components, nose portion 314 and cylindrical section 316. Cylindrical section 316 comprises threaded connector 322 which is used to connect to a flight section (not shown) . Cylindrical portion 316 further comprises connector 320 which is cooperative with connector 322 at the open end of nose portion 314 to attach the cylindrical portion 316 and portion 314 to form an integral base 310. In this example nose portion 314 further comprises internal pillar 340 which is generally cyrindrical and is attached centrally to the inside of nose portion 314. Internal pillar 340 comprises the threaded section 341 which cooperatively interlocks with connection means 345 associated with column 344 which is downwardly suspended from cylindrical section 316. When the nose portion 314 and cylindrical section 316 are connected together, by engaging the various locking devices 341 and 345, and 322 and 320, the internal pillar 340 and column 344 provide structural reinforcement to the nose portion and can thereby enhance the durability, or other physical properties, of a base formed in this manner. Alternatively it may provide a slightly different response characteristic to impact forces on the periphery of nose portion 314 compared to the response characteristics of the embodiment shown in Figure 1 for example. The elasticity of the dome shaped nose portion 314 may be varied in this way. Similarly, further internal structures may be added to provide different engineering support to the dome or to alter the response of a shuttlecock to being hit.

Figure 5 shows a further embodiment of a shuttlecock 401 according to an aspect of the invention. Shuttlecock 401 comprises a flight section 412 made of sixteen natural feathers 431 and a support element 450. The feathers are mounted in the support element 450 which comprises an upper annular ring 451 and lower annular ring 452. The rings are connected by means of struts 453, two of which are shown in cross-section in Figure 5. The stems 454 of feathers 431 pass through apertures in upper annular ring 451 and the ends of the stems 454 pass into apertures in lower ring 452. The shuttlecock base 410 and flight section 412 are engaged by means of cooperative threaded components 422 and 423 associated with the base 410 and the flight section 412 respectively. This type of feather support and method of connecting to the shuttlecock base is similar to that shown in European Patent EP 0157547. That patent describes the use of feather support element 450 to allow easy interchangeability of feathers if they become damaged and also to allow flight speed adjustability by varying the outer diameter of the frusto-conical array formed by the feathers. All disclosures in EP 0157547 are incorporated herein by reference. In this particular embodiment shown in figure 5 flight adjustability can be achieved by relative axial movement of the flight section 412 respect to the base 410. By rotating the base and flight section on their threaded cooperative engaging means, it is possible to vary the inwardly directed force applied to the feather stems 454 at the shoulder 456 at the top of cylindrical section 416. Alternatively a fixed relative construction of feather support 450 and base 410 could be made as described earlier in relation to the embodiment shown in Figure 3.

Referring now to the nose portion 414 of shuttlecock 401 shown in Figure 5. There is shown a thin walled lower section 414 connected to cylindrical section 416 by means of cooperative interlocking means 418 and 420 associated with the nose portion 414 and cylindrical section 416 respectively. The base portion also has an outer covering 470 which is common to the art and is typically made of a fabric material which is adhered to the outer periphery of the base portion 410. It is envisaged that the nose portion 414 may be made of thermo¬ plastics, for example, by injection moulding to create a relatively high density material which is structurally and engineeringly suitable to endure relatively frequent heavy loads. That is loads which typically occur in the game of badminton where the shuttlecock is continually being hit. Since the nose portion is the area most usually hit it must provide suitable response characteristics such as resilience and durability. It is envisaged that to meet these requirements a thin walled nose portion such as portion 414 should have a density greater than 0.2 grammes per centimetre cubed and might typically have the density of the order of 1.0 grammes per centimetre cube.

Thin walled nose portion 414 as shown in Figure 5 is a dome shaped shell which is substantially a hollow hemisphere. It is envisaged that the walls of nose portion 414 need not be of a uniform thickness. The nose portion 414 may be made of non- foamed plastic such as polyethylene and polypropylene. It is possible, for example, to make a suitable nose portion 414 from a 1 to 1 mix of low density polyethylene and polypropylene, although blends can be varied tremendously depending, for example, on the grade of plastics used. Alternative materials might also be used having suitable elastic properties for the nose portion. The cylindrical portion 416 could also be a thin- walled type, such as portion 216 shown in Figure 3. Cylindrical section 416 could be injection moulded from a light rigid material such as polypropylene to provide suitable mechanical properties. It also is envisaged that aperture 499 which passes through feather support 450 could be closed thereby providing a sealed air pocket in the nose portion of the shuttlecock. This closed air pocket could be used to provide suitable mechanical properties to the shuttlecock allowing slight modification to the structure and composition of other components of the shuttlecock to be made during manufacture.

The thin walled nose portion can be defined in terms of the ratio of its average wall thickness to diameter of its hemispherical shape. In this case it is envisaged that a thin walled nose portion according to the invention has an average thickness less than or equal to one tenth of the diameter of an imaginary sphere of which it is a portion. Alternatively, the thin walled nose portion may be defined in terms of its volume relative to the total volume of the hemisphere defined by the outer periphery of the nose portion. A total volume VT equal to the overall volume enclosed within the hemispherical nose portion can be expressed approximately as VT = ( 2/3 )ρi(d/2)³ where d is the diameter of the sphere defined above. Of course the exact mathematical definition of the total volume of a nose portion depends on its exact shape. A volume of space VS can be defined as that volume equal to the volume which is not encapsulated by the walls of the nose portion, that is untrapped space. A third volume VM can be defined as the volume assumed by material of a nose portion together with any directly connected internal struts, such as those shown in previous embodiments which act as mechanical supports or reinforcement to the nose portion. Within this definition of volume, where VT = VS + VM, a nose portion is defined as thin walled if its volume of space VS is greater than or substantially equal to half the total volume VT; that is 2VS > VT. It should be noted that within the definition of volume of space it is envisaged that if the nose portion is filled with micro bubbles or foam which is substantially of a non-structural nature then this too shall count as untrapped air, ie VS, within the above definition.

Referring to figure 6 there is shown a cross-sectional view of a base 510 and feather support member 550 of a shuttlecock 501. The base 510 comprises a thin walled lower portion 514 which is connected to the cylindrical section 516 via connector elements 518 and 520. In order to further improve the quality control of mass produced shuttlecocks this embodiment enable the flight characteristic of a shuttlecock to be varied after production in order to meet the requirements of players and/or competition organising authorities. The flight characteristic of shuttlecock 501 is varied by moving the further support member 550 relative to the feathers and base 510. Feather support member 550 comprises an upper ring 551 which comprises an array of apertures 552 through which the stems of feathers pass in a completed shuttlecock. The upper ring 551 is connected via strut 553 to a lower collar 554. Collar 554 comprises an outer rectangular edge and an inner annular connector 555 which extends inwardly into an aperture defined by collar 554.

The flight support member 550 passes through an aperture 534 in threaded ring 530 which is connected to cylindrical section 516. The cylindrical section 516 comprises a threaded portion 526 which corporate with threading on ring 530 so that ring 530 can be securely attached to the base 510. It is envisaged however that lower ring 530 may be an integral moulded part of base 510. The ring 530 comprises apertures 532 through which the lower end of feather stems are passed in a completed shuttlecock. The ends of the feathers pass into recess 524. The shape and configuration of apertures 532 can act to bias the feathers in a frusto-conical array having a predetermined radial extent. The feather support member 550 is journalled in central aperture 534 of ring 530 and can slide freely therein. The feather support member 550 is caused to move axially through aperture 534 by means of adjuster device 580. In a preferred form collar 554 has a rectangular shaped outer periphery, that is viewed axially (from above in figure 6) , and similarly aperture 534 has a rim which is rectangular in transverse section. This shaping prevents feather support 550 rotating relative to the base 510.

Adjuster 580 comprises a lower threaded portion 581 and upper connector portion 583. The upper portion further comprises a recess 582 and an outer chamfered rim 584. The adjuster 580 is clipped onto feather support member 550 by passing it through the aperture defined by collar 554 causing ring 555 to pass over the cam surface of rim 584 and fall into a recess provided in the adjuster head 583. The adjuster is thereby rotatably connected to the support 550 and is able to freely rotate on annulus 555. The lower threaded portion 581 of adjuster 580 cooperates with a threaded connector portion 528 of cylindrical section 516. By screwing adjuster 580 into connector 528 the relative axial position of feather support member 550 is varied with respect to the base 510. Axial movement of adjuster 580 can be achieved in the embodiment shown by inserting the nib of a pencil into recess 582, which has a high friction surface, and rotating the pencil to cause rotational movement of the adjuster 580. Alternatively, it is envisaged that adjuster 580 may comprise a recess shaped to take a tool such as a screwdriver or other device specifically designed to fit a given shape of recess in the top of adjuster 580.

When completed, feathers pass through apertures 552 in upper ring 551 and through apertures 532 in lower ring 530. Since lower ring 530 is fixed relative to the base the outer diameter extent of the feathers depends upon the relative axial position of apertures 552. The outer rims of apertures 552 act to restrain the outer diameter extent of the feathers. By moving upper ring 551 closer to base 510, the effective outer diameter of the feathers can be increased and the feathers effectively pivot about their retaining apertures 532 in lower ring 530. Thus, feather support 550 needs to be relatively rigid in order to provide sufficient retaining force to hold the feathers in position. Alternatively, it is envisaged that the feathers may not be biased to a large diametrical extent, as in the case just described, (which requires a restraining force to be exerted by upper ring by 551 ) but rather that the feathers may be inwardly biased so that ring 551 effectively pushes the feathers out when it is lowered with respect to the base 510. In a further alternative the feathers may be held in a equilibrium central position which requires the upper ring 551 to exert an outward force on the feather stems to cause a greater diameter extent of the feather array, or alternatively to cause an inwardly directed force on the feather stems when upper ring 151 is raised with respect to base 510.

Claims

1. A shuttlecock for playing badminton comprising a base and a flight section wherein the base includes a thin- walled nose portion to be struck during play.

2. A shuttlecock as claimed in claim 1 wherein the nose portion is substantially hemispherical.

3. A shuttlecock as claimed in claim 2 wherein the nose portion has a wall thickness less than or substantially equal to one tenth the diameter of said nose portion.

4. A shuttlecock as claimed in claims 1, 2 or 3 wherein the nose portion has a total volume defined by the outer periphery of the nose portion and encompassing all material and untrapped space within the periphery wherein the volume of untrapped space is greater than or equal to half the total volume.

5. A shuttlecock as claimed in any of the previous claims wherein the nose portion comprises internal structural members and wherein optionally the internal structural members act to reinforce the nose portion.

6. A shuttlecock as claimed in any of the preceding claims wherein the base further comprises a cylindrical section depending from the nose portion and wherein optionally the cylindrical section and the flight section each comprise cooperative interlocking means.

7. A shuttlecock as claimed in claim 6 wherein the cooperative interlocking means are screw-threaded and allow the cylindrical section and the flight section to be readily engaged and disengaged.

8. A shuttlecock as claimed in claims 5 and 6 wherein the internal members and cylindrical section each comprise cooperative engaging means to attach one to the other.

9. A shuttlecock as claimed in claim 6 wherein the cylindrical section attaches to the nose portion by a frictional mating device.

10. A shuttlecock as claimed in any of the previous claims wherein the base comprises an outer layer of covering material such as a fabric.

11. A method of making a shuttlecock comprising the step of forming a thin walled nose portion of a base thereto using a suitable forming process.

12. A method as claimed in claim 11 wherein the suitable forming process is injection moulding.

13. A base portion of a shuttlecock for playing badminton which portion comprises a thin-walled nose portion.

14. A shuttlecock for playing badminton comprises a base, an array of feathers, a feather support which is connected to the feathers and determines the radial extent of the feathers, and an adjustment device which is connected to the feather support and the base and which enables relative movement of the feather support with respect to the feathers thereby enabling the configuration of the array of feathers to be altered.

15. A shuttlecock as claimed in claim 14 wherein the feathers have a fixed axial position relative to the base and the feather support is moveable axially relative thereto.

16. A shuttlecock as claimed in claim 15 wherein the feather support comprises a ring having an array of apertures through which feather stems pass.

17. A shuttlecock as claimed in any of claims 14, 15 or 16 wherein the adjustment device is a separate device and is connected to the feather support and freely rotatable relative thereto.

18. A shuttlecock as claimed in any of claims 14 to 17 wherein the adjustment device and base comprise cooperating threaded portions.

19. A shuttlecock as claimed in any of claims 14 to 18 combined with features defined in any of claims 1 to 10.

20. Use of a shuttlecock as claimed in any of claims 1 to 10 and/or 13 to 19 to play the game of badminton.