GB2467730A - Dart - Google Patents

Abstract

A dart comprises a tip, a barrel and a stem adapted to hold a flight. The weight of the stem is in the range between 20-40% of the weight of the barrel, and is preferably approximately 30% of the weight of the barrel. The stem may comprise stainless steel and may weigh approximately 5g. The stem may have first and second end portions 1, 3 connected by a central shaft portion 6 of a smaller diameter. Preferably the first end portion 1 is adapted to hold the flight and the second end portion 3 comprises means for attaching the stem to the barrel. The purpose of the stainless steel stem is to redistribute weight towards the back of the dart, thus producing a resting angle in the dartboard of 0-5 degrees below the horizontal. This reduces visual obstruction of the scoring area.

Description

Improved Dart

Field of the invention

The invention relates to darts, and in particular to the stem part that is attached to the barrel and holds the flight in place.

Background to the invention

In the sport of darts, it is widely recognised that the darts land in the dartboard at an angle of between 2O3O0 above the horizontal. However, due to the darts penetrating the board at such angles, the barrel, stem and even the flight can cause both a visual and physical obstruction of the scoring area. This results in a player having to stop and move or adjust along the oche (throwing line) some considerable distance in order to achieve a better angle to attack the intended scoring bed. This break in concentration and throwing momentum often leads to the next darts thrown being wasted as the rhythm is lost as players become aggrieved and focus too much on the fact their view is either partially or totally blocked and so try to overcompensate. The result being the next darts failing to land where intended, due to the break in concentration and throwing momentum.

The structure of a typical dart consists of a tip, barrel, shaft/stem and flight and is shown in Fig. 1.

Most modern day dart barrels are manufactured from a tungsten alloy and can weigh anywhere between 1 3-45g depending on the grade of tungsten used and the dimensions of the barrel itself. The prior art of this invention is currently made from either plastic or aluminium and due to the lightweight properties of these materials, weighs approximately 1.5g.

As a result of this arrangement, where the dart barrel weighs considerably more than the stem, the dart therefore becomes front heavy". And this has an effect on the darts' trajectory, causing the dart to land in the board at an angle of between 20- 30° above the horizontal, thus providing both a visual and physical obstruction of the scoring area to the player.

The behaviour of a dart during its initial entry into the board is such that as it enters the board having been thrown, it does so at a particular angle, say for example 23° above the horizontal. Now this angle then decreases slightly, say for example down to 210 above the horizontal, as the dart slows down and comes to rest in the board.

This 2-3° reduction in angle is due in part to both the weight of the dart itself and the behaviour of the bristle fibres from which the dartboard is constructed.

Due to the prior art being made from plastic or aluminium and weighing between 1- 1.5g, they have no real affect on the landing or resting angles the dart assumes in the board.

Statement of Invention

According to an aspect of the present invention, there is provided a dart comprising; a tip; a barrel; and a stem adapted to hold a flight; wherein the weight of the stem is in the range between 20-40% of the weight of the barrel.

In one embodiment of the present invention, providing a stem which weights between 20-40% of the weight of the barrel means that during flight, the dart is nearly perpendicular to the board and so as it enters the board with the added weight at the rear, the dart then assumes a new resting angle in the dartboard of between 0-5° below the horizontal.

Preferably, the weight of the stem is approximately 30% of the weight of the barrel.

Preferably, the dart stem comprises stainless steel. The added weight of the steel in comparison with the prior art of plastic and aluminium stems results in the steel stem having a larger effect on the resting angle of the dart in the dartboard. In terms of numbers, the steel stem weighs approximately 5g in comparison with the plastic and aluminium stems that weigh between 1-1.5g. The innovative dart stem works by causing a redistribution of weight, from the front toward the back of the dart.

Preferably, the dart stem has a smaller diameter central shaft portion with larger diameter sections at either end.

Preferably, a first end section acts as a flight holder and a second end section providing means for connecting the stem to the dart barrel.

Preferably, the second end section comprises a threaded spigot at to engage a corresponding threaded recess (0 2ba) in the dart barrel.

Preferably, the stem is manufactured in one piece with no additiona attachments.

An embodiment is shown in Fig 2, where the flight retaining part (first end section) forms part of the main body of the stem, and is subsequently made from stainless steel.

Preferably, the first end section has a plurality of slits extending longitudinally from the one end and into which the dart flight may be inserted and retained therein.

Alternatively, the first end section may require a threaded recess to be created, thus allowing a metal flight retaining part with corresponding threaded spigot to be attached in order to hold the flight in place as shown in Fig 3.

Preferably, the flight retaining part is manufactured from aluminium or an alloy thereof.

Preferably, the flight retaining part has a plurality of slits extending longitudinally from the one end and into which the dart flight may be inserted and retained therein.

Preferably, the stem has a locking hole drilled through a tapered part of the stem, thus allowing the point of another dart to pass through and allowing the stem to be tightened on to the barrel should it slacken off during play.

Preferably, the outer diameters of the mating faces of the stem and the barrel should be equal both for aerodynamic and aesthetic purposes.

Preferably, the outer diameters of the mating faces of the stem and flight retaining part should be equal both for aerodynamic and aesthetic purposes.

Detailed Description of the Drawings

* Figure 2 is a plan view of the desired one piece dart stem.

* Figure 3 is a plan view of the alternative two piece dart stem with screw in flight holder.

Figure 2 shows a dart stem manufactured from stainless steel. The stem has at one end portion (1) a cruciform slot (2) that forms the dart flight holder, thus holding the flight in position (7) and at the other end portion (3) a means, in the form of a screw thread (4) for connecting it to a corresponding threaded recess in the dart barrel.

Also found within the end portion (3) is a locking hole (5) that allows the dart point to pass through it, allowing the stem to be tightened onto the barrel. The two end portions (1&3) are interconnected by a central shaft portion (6) of a slightly lesser diameter. The stem can be manufactured by turning steel billets on a lathe. The billet is supported by a running centre at one end, while being gripped in the chuck at the other. This supporting between centres ensures that the axis of the hole is running parallel with the outside diameter. A driving dog can be created and used to turn or drive the part around, allowing the tool to be placed in position in order to create the stem shape. The screw thread (4) can be created using a 2ba threading die, the standard size used in all modern dart stems.

Figure 3 shows the alternative two piece dart stem with screw in flight holder. This stem has at one end portion (1) a cruciform slot (2) that forms the dart flight holder, thus holding the flight in position (7). The stem has a threaded recess (9) into which the corresponding threaded peg (8) of the aluminium flight retaining part (1) can be screwed in. The tap and thread dimensions are arranged as such to provide a relatively tight fit when screwed together. At the other end portion (3) a means, in the form of a screw thread (4) for connecting it to a corresponding threaded recess in the dart barrel. Also found within the end portion (3) is a locking hole (5) that allows the dart point to pass through it, so the stem can be tightened onto the barrel. The two end portions (1 &3) are interconnected by a central shaft portion (6) of a slightly lesser diameter. The main part of the stem can be manufactured by turning steel billets on a lathe as described previously, with the screw thread (4) created using a 2ba threading die. The only additional manufacturing is the drilling and tapping of the threaded hole (9), the size of which is determined by the size and type of thread on the aluminium flight retaining part (8).

Figures 4, 5 &6 highlight the problems of the prior art perfectly.

Meanwhile Figures 7, 8 & 9 show the results of throwing a dart using the innovative dart stem.