Improved dart

Abstract

A dart (10, Figure 1) comprising a barrel 12 and a shaft 16, the barrel 12 and shaft 16 connected via corresponding threaded portions 24 / 30, wherein the barrel 12 and shaft 16 further comprise a plura

Description

Field of the Invention The present invention concerns a dart. More particularly, but not exclusively, this invention concerns the connection between the barrel of a dart and the shaft of a dart. Background of the Invention Darts is a game in which darts are thrown at a dartboard, and various scores are awarded depending on where the dart is received by the dartboard. A typical dart comprises a barrel which is held by a player when throwing the dart, a point extending from one end of the barrel which impacts and is received by the dartboard, a shaft extending from the other end of the barrel, and a flight at the distal end of the shaft which stabilises the dart when it is thrown. The flight may be a separate component to the shaft and inserted into slots at the distal end of the flight, or the shaft and flight may be a single, for example moulded, component. The shaft is typically joined to the barrel by insertion into the barrel and engagement of corresponding threaded portions of the shaft and barrel. During use, the dart experiences many impacts which may cause the connection between the shaft and the barrel to become loose, requiring regular retightening of the connection. Existing attempts to solve this include rubber O-rings located between the barrel and shaft, but such arrangements may still come loose, and may also negatively effect the aesthetic appearance of the dart. The present invention seeks to mitigate the above-mentioned problems. Alternatively or additionally, the present invention seeks to provide an improved dart. Summary of the Invention The present invention provides, according to a first aspect, a dart comprising a barrel and a shaft, the barrel and shaft connected via corresponding threaded portions of the barrel and shaft, wherein the barrel and shaft further comprise a plurality of corresponding mating formations, and the mating formations engage to resist rotational movement of the shaft relative to the barrel. The skilled person will appreciate that a dart has a longitudinal axis extending along the barrel and the shaft, and rotational movement of the shaft relative to the barrel is along this axis. It will also be appreciated that the threaded portions of the barrel and the shaft extend along this axis, and the threaded portions are engaged and disengaged by rotational movement in the appropriate direction along this axis. The dart may further comprise a point. The shaft may be connected to the barrel at a rear end of the barrel and the point may be connected to a front end of the barrel. The skilled person will appreciate that darts have a front / rear orientation, with the front end being the direction in which it is intended the dart is thrown. A flight may be inserted into the free end of the shaft, which may stabilise flight of the dart when thrown. It is common that the barrel may be a metal barrel, for example a tungsten alloy, brass, or nickel-silver barrel. The barrel may be machined by a billet of metal. The billet may have a point hole and a threaded hole, the point hole at the front of the barrel for engagement with the dart point and the threaded hole at the rear of the billet for engagement with the shaft. During machining, the threaded hole may be engaged with a headstock of the machining tool and the point hole may be engaged with a tail stock. The headstock drives the rotation of the billet and the tailstock supports the billet during machining. In order to drive rotation of the billet, it is common for the headstock to extend partially into the threaded hole and have a series of teeth which form impressions within the threaded hole. The applicant has realised that those impressions may be used as mating formations in the barrel of the present invention. Therefore, the mating formations of the barrel may be formed as a by-product of the machining process. The mating formations of the shaft may be configured to engage with the mating formations of the barrel only when the shaft is fully screwed into the barrel. Such an arrangement may be advantageous as allowing the shaft to be inserted and partially screwed into the barrel with ease, and the mating formations engage and resist rotational movement of the barrel and shaft when the barrel and shaft are fully engaged with one another. Preferably the resistance to rotational movement can be overcome by a user of the darts to allow replacement of the shaft in the event of damage or for any other reason the user wants to replace the shaft. The shaft may comprise a shoulder surface, the shoulder surface abutting the barrel. The mating formations of the shaft may extend from the shoulder surface of the shaft. The present invention provides, according to a second aspect, a dart shaft, the shaft comprising a threaded portion to allow connection to a dart barrel with a corresponding threaded portion, and a plurality of mating formations, the mating formations configured to engage with corresponding mating formations of the dart barrel to resist rotational movement of the shaft relative to the barrel. The dart shaft may be joined with a suitable barrel to form a dart according to the first aspect of the invention. As many darts will already comprise a barrel with various internal indentations left at the threaded hole end of the barrel due to a machining process, the dart shaft according to the second aspect of the invention may be retrofit to an existing dart. It will of course be appreciated that features described in relation to one aspect of the present invention may be incorporated into other aspects of the present invention. For example, the second aspect of the invention may incorporate any of the features described with reference to the first aspect of the invention and vice versa. Description of the Drawings Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings of which: Figure 1 shows a schematic view of a dart according to a first embodiment of the invention; Figure 2 shows an exploded cross-sectional view of part of a dart according to the invention; Figure 3 shows a perspective view of part of a dart shaft according to the invention; and Figure 4 shows an end-on cross-sectional view of the rim of a barrel according to the invention. Detailed Description Figure 1 shows a dart 10 comprising a barrel 12, with a point 14 extending from the front end of the barrel 12, a shaft 16 extending from the rear end of the barrel 12, and a flight 18 extending from the rear end of the shaft 16. The skilled person will appreciate that the dart 10 is intended to be thrown point 12 first, and the front F and rear R directions are relative to this intended use. Figure 2 shows an exploded cross-sectional view of the barrel 12 and shaft 16, and figure 3 shows a perspective view of the front end of the shaft 16. The barrel 12 is metal and machined from a billet piece. The barrel 12 comprises a point hole 20 in which the point 14 is inserted and held in place with an interference fit. The barrel 12 further comprises a threaded hole 22 into which a thread has been cut to provide a threaded portion 24. The threaded hole 22 ends at the rear end of the barrel 12, where a rim 26 with a greater circumference than the threaded portion 24 is located. When the barrel 12 is machined from a billet piece, a tail stock is located in the point hole, and a headstock is inserted into the rim 26, and teeth on the headstock bite into and form indentations in the rim 26. The tailstock supports the billet piece whilst the headstock is driven to rotate the billet piece around the longitudinal axis of the barrel 12. On removal of the headstock the indentations in the rim 26 remain, and form mating formations 28. The shaft 16 is a moulded plastic component. The front-most part of the shaft 16 is a threaded portion 30 which is inserted into the threaded hole 22, and the shaft 16 rotated to engage the threaded portion 30 of the shaft 16 with the threaded portion 24 of the barrel 12. The shaft 16 further comprises a spindle 32 extending away from the threaded portion 30 and a shoulder 34, at which point the shaft 16 increases in diameter. The threaded portion 30 and spindle 32 are located within the threaded hole 22, and the shoulder 34 abuts the outer part of the rim 26. The shaft 16 further comprises mating formations 36 which extend away from the shoulder 34, and engage with the mating formations 28 of the rim 26 when the shaft 16 is fully tightened into position. In this embodiment, the mating formations 28 of the rim 26 extend all around the rim 26, due to the tooth pattern in the headstock which was used when machining the barrel. The shaft 16 comprises four mating formations 36 which are equally spaced radially around the circumference of the shaft 16. The skilled person will appreciate that alternative mating formation patterns may be provided on either or both of the barrel 12 and shaft 16. Figure 4 shows an end-on view of the barrel 12, with the dashed lines showing the mating formations 36 of the shaft 16, demonstrating how the mating formations 28 of the barrel 12 engage with the mating formations 36 of the shaft 16, thereby resisting rotational movement between the barrel 12 and the shaft 16. Whilst the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein. By way of example only, certain possible variations will now be described. In the above described embodiment, the mating formations in the barrel are formed during the machining of the barrel from a billet piece. In alternative embodiments, the mating formations may be formed in a separate step and be unrelated to other manufacturing steps relating to the barrel. In the above described embodiment, a certain pattern of mating formations is shown. The skilled person will appreciate that many different alternative patterns may be provided, so long as the pattern of mating formations is such that they engage one another to resist rotational movement of the shaft relative to the barrel. Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments.

Claims

1. A dart comprising a barrel and a shaft, the barrel and shaft connected via corresponding threaded portions of the barrel and shaft,wherein the barrel and shaft further comprise a plurality of corresponding mating formations, and the mating formations engage to resist rotational movement of the shaft relative to the barrel.

2. A dart according to claim 1, further comprising a point.

3. A dart according to claim 1 or claim 1, further comprising a flight extendingfrom the shaft.

4. A dart according to any preceding claim, wherein the barrel is a metal barrel.

5. A dart according to any preceding claim, wherein the barrel is machined froma billet of metal.

6. A dart according to claim 5, wherein the mating formations of the barrel are formed as a by-product of the machining process.

7. A dart according to any preceding claim, wherein the mating formations of the shaft are configured to engage with the mating formations of the barrel only when the shaft is fully screwed into the barrel.

8. A dart according to any preceding claim, wherein the shaft comprises a shoulder surface, the shoulder surface abutting the barrel and the mating formations of the shaft extend from the shoulder surface of the shaft.

9. A dart shaft, the shaft comprising a threaded portion to allow connection to a dart barrel with a corresponding threaded portion, and a plurality of mating formations, the mating formations configured to engage with corresponding matingformations of the dart barrel to resist rotational movement of the shaft relative to the barrel.

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