US 3904205 A
A shuttlecock having a base and a single piece injection molded plastics skirt is provided, which has flight characteristics and feel closely resembling feather shuttlecocks. The molded flared skirt has lower and upper portions, the upper portion being provided with a plurality of radially spaced stems of channel section, such as V-, C- or U- section. Intermediate the stems of the upper skirt there is provided a lattice structure which defines a plurality of slots set at an acute angle to the longitudinal axis of the shuttlecock. For attachment of the base to the skirt, the latter is provided with an integrally formed spigot formation having at least two spaced legs, each having a radially extending projection engageable with an annular groove formed internally of the base.
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Description (OCR text may contain errors)
United States Patent 1 Robinson 451 Sept. 9, 1975 1 1 SHUTTLECOCK  Filed: June 11, 1973  Appl. No.: 368,664
2,632,647 3/1953 Carlton, 273/106 A 3,313,543 4/1967 Carlton 273/106 A 3,749,403 7/1973 Austin ct a1 273/1065 C FOREIGN PATENTS OR APPLICATIONS 1,103,364 2/1968 United Kingdom 273/106 A United Kingdom 273/106 A Canada 273/106 A Primary Examiner-Paul E. Shapiro Attorney, Agent, or FirmMiller, Frailey & Prestia  ABSTRACT A shuttlecock having a base and a single piece injection molded plastics skirt is provided, which has flight characteristics and feel closely resembling feather shuttlecocks. The molded flared skirt has lower and upper portions, the upper portion being provided with a plurality of radially spaced stems of channel section, such as V-, C- or U- section. Intermediate the stems of the upper skin there is provided a lattice structure which defines a plurality of slots set at an acute angle to the longitudinal axis of the shuttlecock. For attachment of the base to the skirt, the latter is provided with an integrally formed spigot formation having at least two spaced legs, each having a radially extending projection engageable with an annular groove formed internally of the base.
7 Claims, 2 Drawing Figures PATENTED 1975 SHEET 1 [1F 2 SHUTTLECOCK This invention relates to shuttlecocks, more particularly to shuttlecocks of the type having a plastics skirt.
Many shuttlecocks having a plastics skirt have been produced and proposed but in all the prior construe tions the flight characteristics and feel during play have been very different from the characteristics and feel of conventional feather shuttlecocks, As a result shuttlecocks having a plastics skirt have been treated as inferior substitutes for feather shuttlecocks and have not gained acceptance in the higher standards of the game of badminton.
It is an object of the present invention to provide a shuttlecock having a plastics skirt which has flight characteristics and fee] which more closely resemble the characteristics and feel of feather shuttlecocks than plastics skirted shuttlecocks which are presently available.
According to one aspect of the present invention a shuttlecock skirt comprises a lower skirt adjacent the base and an upper skirt remote from the base, at least the upper skirt being resilient and comprising a plurality of radially spaced longitudinally extending stems which are of hollow section, i.e. channel section, over at least a portion of their length. The stems of the upper skirt may continue to form stem portions in the lower skirt and, if desired, the stem portions in the lower skirt may also be of channel section.
The number of radially spaced stems in the upper skirt is preferably from 8 to 18 inclusive although it is particularly preferred to employ l6 stems.
The stems in the upper skirt are preferably of hollow section over at least 50% of their length, more preferably 75% of their length; advantageously they are of hollow section over substantially their whole length.
The hollow or channel section of the stems may be C-, U- or V shape and the shape of the section may vary along the length of the portion of the stem have a hollow section. It is desirable that a thickened zone extends centrally along at least a portion of the length of the hollow portion each stem.
The stems in the upper skirt may be of substantially uniform width along their length or may be tapered over at least a portion of their length so that the stem is narrower at a position more remote from the base than at a position nearer the base.
The width of the stems, measured along the outer periphery thereof, may be, for example, in the range 4 to mm, preferably 4 to 8 mm. A suitable width has been found to be 6 mm either extending along substantially the whole length of the stem or tapering towards a width of about 4 mm at the end of the stem remote from the base.
The stems in the upper skirt support a lattice structure intermediate the stems. The lattice structure may be simple or complex but is is preferred to provide sim ple lattice strips extending from one stem to the next adjacent stem. These lattice strips may be connected together by one or more supporting strips extending generally parallel to the stems.
In order to facilitate folding of the shuttlecock under impact, which is necessary to achieve the desired feel and sound, the lattice structure intermediate the stems may be fluted. Alternatively, the lattice structure may be discontinuous around the circumference of the shuttlecock, eg the portion of the lattice structure extending from one stem is not connected to the portion of the lattice structure of the next adjacent stem. In this way, the shuttlecock can collapse under impact in a manner similar to that of a conventional feather shuttlecock.
it is desirable that the lattice structure. whether it is continuous or discontinuous, defines a plurality of slots which are set at an acute angle to the longitudinal axis of the shuttlecock. Advantageously, such angled slots comprise at least 50% of the apertured area of the lat tice Structure.
The use of such angled slots affords a very convenient way of introducing spin to the shuttlecock which is important in maintaining a consistent and true flight path after the shuttlecock has been struck by a racket.
In certain constructions it may be possible to construct the lattice in such a manner that the lattice strips present an aerofoil section to the air during flight so that the pressure on the lattice strips tends to expand the skirt. Such an arrangement assists the shuttlecock to regain its normal shape quickly and also provides ad ditional air resistance which helps to improve the flight characteristics of the shuttlecock.
It is preferred that the skirt, at the extremity remote from the base has an undulating profile in the plane of the skirt immediately beneath the profile, Desirably, the undulating profile is arranged so that it simulates the profile of a conventional shuttlecock having either pointed or rounded feather tips, although it is preferred to provide pointed tips.
The area of the undulating profile portion, ie that area which lies more remote from the base than a circumferential line parallel to the base and passing through the lower extremities of the undulations, is at least 50% imperforate. Preferably, the area is at least imperforate.
The presence of an undulating profile at the extremity of the skirt remote from the base has been found to improve the performance of shuttlecocks relative to those having a straight extremity, particularly as regards so-called net-play" which is very critical in the higher standards of the game of badminton,
The skirts may be produced by any conventional technique utilised in producing plastics objects, including moulding and fabrication techniques. The preferred method is injection moulding since this process is cmi nently suitable for large production runs.
The skirts may be produced from a variety of materi als. Where fabrication techniques are employed plastics stems may be produced, eg by injection moulding, and a lattice structure of plastics; natural fibres; fabric, either woven or non-woven; paper; or similar materials may be secured thereto, either by adhesive or by the provision of a suitable formation on the stems for en gagement by the lattice structure.
Where the skirts are injection moulded in one step it is preferred to use a plastics material of relatively low specific gravity in order to keep the weight of the skirt to a minimum. Materials which we have used to pro duce shuttlecocks include, polyethylene, polypropylene, blends of polyethylene and polypropylene, blends of these polymers with EVA, nylons, particularly nylon 11, and ABS. It will be apparent that other polymers could be used, if desired. provided that they have the necessary toughness and they satisfy the weight re quirements in the finished shuttlecock.
Where a fluted skirt is to be produced a conical skirt may be moulded initially and then fluted in a subsequent forming operation. Such a process is described in British Patent Specification No 751,577. If desired, the hollow section stems may also be produced using this technique.
It is, however, preferred that the skirt is produced in a single moulding operation. In this way, the hollow section stems can have a much more precise shape than that obtained with a second forming operation, and, in addition, the moulding-in of the hollow section affords a more rigid structure which is desirable from the point of view offast recovery of shape after impact of the shuttlecock with a racket.
The thickness and width of the stems which may be used depends on the available weight of material, bearing in mind the number of stems employed, the weight of material in the lattice structure and the total weight of material which will give the shuttlecock a satisfactory turnover and flight,
Generally, the total weight of material available in the skirt is 2.00 to 3.00 grams, preferably 2.00 to 2.70 grams, and more preferably 2.30 to 2.50 grams. The precise weight chosen will depend upon the distribution of the weight relative to the base.
The hollow section stems may be tapered from the centre to the sides in any plane which is perpendicular to the longitudinal axis of the shuttlecock skirt. The thickness at the centre line of the hollow section stems in the upper skirt will generally have a maximum thickness in the range 0.01 inches to 0.03 inches, preferably 0.01 to 0.02 inches, and a minimum thickness in the range 0.005 to 0.01 inches, preferably 0.005 to 0.008 inches. The thickness at any point remote from the centre line will generally have a maximum thickness of 0.015 inches, preferably 0.01 inches, and a minimum thickness in the range 0.005 to 0.01 inches, preferably to 0.008 inches.
Adjacent the longitudinal edges of the hollow section stems, particularly in the upper skirt there may be provided a rib which tends to prevent tearing of the stem material and thus prolongs the useful life of the shuttlecock. This rib will usually be of generally circular crosssection and have a diameter of 0.01 to 0.20 inches mm.
The skirt is provided with a lower skirt which may comprise merely extensions of the stems in the upper skirt or may be of different construction. In one embodiment the lower skirt comprises a plurality of stems of triangular cross-section connected at one end to a base ring and at the other end to a support ring which carries the upper skirt.
The lower skirt is connected to a formation which enables it to be secured to a separate base or, if desired, the base may be formed integrally therewith. Where a separate base is employed the formation may comprise a spigot formation which can locate in a socket in the separate base. If desired, it may be secured thereto by a suitable adhesive.
Conveniently the spigot formation includes at least two legs, each having a radially extending portion. Advantageously, an insert is shaped to fit between the legs to hold them against deformation, and to this end the legs may include a shoulder portion to locate the insert.
The provision of a weight element in the base of a shuttlecock is generally necessary in order to achieve the desired speed. Different weights are used to provide shuttlecocks of different speeds a range of 'speeds being necessary to suit the various playing conditions which may be encountered.
It is thus an aspect of this invention to provide an insert which constitutes, at least in part, a weight element of a shuttlecock. Inserts of various weights may be used to provide the different speeds of shuttlecock, or a standard insert may be used in conjunction with an auxiliary weight member.
Desirably the insert or auxiliary weight member is keyed e.g. by reference numerals or colour coding in such a way that the key is visible through the bottom of the skirt when the skirt is attached to the base. The reference numerals may correspond to the speed ratings generally in use for conventional feather shuttlecocks, which generally lie in the range 78 to 85.
The invention is hereafter more particularly described with reference to the accompanying drawings, in which:
FIG, 1 is a side elevation of one form of shuttlecock; FIG. 2 is a top view of the shuttlecock shown in FIG.
FIG. 3 is a side elevation of a further form of shuttlecock;
FIG. 4 is a cross-section of one form of spigot; and
HG. 5 is a base for use with a spigot formation.
FIG. 6 is a cross-sectional view taken as indicated by the lines 66 in FIG. 1.
The shuttlecock comprises a base 10 attached to a skirt 11 by a spigot formation (not shown) which is located in a corresponding socket in the base 10.
The base 10 is moulded separately from the skirt from an expanded material, such as expanded polyvinyl chloride and includes a socket to receive the spigot formation on the skirt.
The skirt comprises an upper skirt l3 and a lower skirt 14 formed integrally with one another and with the spigot formation by injection moulding.
The lower skirt 14 comprises 16 lower stems l5 radially distributed about the longitudinal axis of the shuttlecock and supporting at their ends remote from the base a circumferential support ring 16. The lower stems 15 are of triangular section and are tapered away from the base; at their lower, thicker, end they are connected by a base ring 17 which extends both above and below the top of the base.
The upper skirt 14 comprises upper stem portions 19 which are aligned with the lower stems 15 but are broader and thinner and are of V-section as can be seen in FIG. 2. The upper stern portions 19 may be of any similar channel-like hollow section, such as U-section or C-section, to thereby provide a relatively rigid structural effect to the upper stems of the skirt 11.
The upper stem portions 19 terminate in pointed tips 20 which form part of the pointed upper edge 21 of the skirt which is shaped to simulate that of a conventional feather shuttlecock having pointed feather tips.
The points of the upper edge 21 extend from an imaginary circumferential line parallel with the top of the base and passing through the lower extremities of the V-shaped slots intermediate the points.
The area of the points of the upper edge 21 is thus largely imperforate.
Intermediate the upper stem portions 19 there extends a fluted lattice structure which defines a plurality of parallel slots 23 set at an acute angle to the longitudinal axis of the shuttlecock. A supporting rib 24 is formed transverse to the slots 23.
A modified from of shuttlecock is shown in FIG. 3.
In this shuttlecock, the skirt is generally similar to that shown in FIGS. 1 and 2 but the lattice structure is not fluted and is discontinuous, the lattice strips being divided from each other along the lines 31. It will be appreciated that the lattice strips can, if desired, be offset from one another.
One way of attaching the shuttlecock to the base is shown in FIG. 4. The spigot formation comprises four legs 50 having peripheral radial projections 51. The legs are provided with a shoulder 52 to locate a solid cylindrical insert 53 which also serves as a weight ele ment.
The insert 53 is held against the shoulder by the base 54 when this is assembled with the skirt. The legs 50 locate in the cylindrical socket 55 and the radial projections 51 locate in the circumferential groove 56. The groove 56 is formed by contraction of the base onto the spigot formation.
This arrangement positively locates the weight element and prevents its movement during use, thus giving the shuttlecock a predictable and consistent flight characteristic.
It will be apparent that the embodiments described above may be modified within the scope of the present invention.
What we claim is:
l. A shuttlecock skirt comprising a lower skirt and an upper skirt, the upper skirt being resilient and having a plurality of radially spaced longitudinally extending stems which are of channel section over at least a portion of their length and further having, intermediate said stems, a lattice structure which defines a plurality of angled slots which serve to introduce spin when the shuttlecock is in flight, the lower skirt comprising a plurality of radially spaced longitudinally extending stems of triangular section.
2. A skirt according to claim 1 in which the lattice structure is fluted.
3. A skirt according to claim 1 in which the extremity remote from the base has an undulating profile in the plane of the skirt immediately beneath the profile.
4. A skirt according to claim 3 in which the area of the undulating profile portion is at least 50% imperforate.
5. A shuttlecock having a base and a single piece injection molded plastics skirt providing flight characteristics and feel simulating the flight characteristics and feel of feather shuttlecocks, said skirt comprising a. a lower skirt comprising a plurality of radially spaced longitudinally extending stems of triangular configuration,
b. a resilient upper skirt, said upper skirt having i. a plurality of radially spaced longitudinally extending stems which are of channel section over at least a portion of their length and,
ii. intermediate said stems, a lattice structure which defines a plurality of angled slots which serve to introduce spin when the shuttlecock is in flight, and
c. a spigot affixed to the lower skirt for securing the base to the skirt.
6. A shuttlecock skirt comprising a. a lower skirt,
b. an upper skirt,
c. at least the upper skirt being resilient and having a plurality of radially spaced longitudinally extending stems,
d. a lattice structure intermediate said stems, which define a plurality of angled slots which serve to introduce spin when the shuttlecock is in flight, and
e. a spigot formation to permit attachment of a base, the spigot formation comprising at least two legs, each having a radially extending portion.
7. A skirt according to claim 6 in which the legs include a shoulder portion to locate an insert.