This invention relates to a dart of the kind present- ^' ed in the preamble to claim 1.

Darts are used in the game of darts, where the darts are thrown at a circular target of a material into which the darts can penetrate, e.g.- a felt-like mat¬ erial, coiled-up paper or cardboard, or hair disposed in a parallel manner, e.g. horsetail hairs with the hair direction at right-angles to the plane of the target. The target is divided into fields of various numerical value, and these fields are separated by steel wire so that there can never be any doubt con- cerning in which field the dart is sitting.

During a game of darts, a number of the darts make direct hits on the steel wire and fall to the floor, and thus do not give any points. Since those fields which give the most points are quite small, the num¬ ber of darts which hit the steel wire and fall to the floor in this manner is relatively high. There¬ fore, skilled dart players calculate that 7-12% of the darts thrown do not give any points, the reason being that these fall to the floor after having hit . the wire. Moreover, the darts which fall to the floor can suffer damage, which is certainly not with¬ out significance when the darts are of the expensive kind used for tournaments and competitions.

Attempts have been made to solve this problem by con¬ structing the darts in special ways. The most common¬ ly-used darts have the point itself rigidly secured, e.g. soldered firmly to the dart barrel. Many tests

have proved that 7-12% of the thrown darts of this type fall to the floor.

From the description of English patent no. 1,541,886, a construction is known where the dart point is moun¬ ted in a resilient manner in a cylindrical chamber extending lengthwise in the dart barrel. When the point of the dart hits the target or the steel wire, the dart point is halted, but the barrel continues to move towards the target, in that the spring is com¬ pressed until the barrel urges the point into the tar¬ _g et in a harαrer-like manner, namely when the spring is pressed completely together. The patent describes a number of trial throws , partly 2 attempts with darts without flights, and 8 trial throws with darts having different flig¬ hts.. In all of the_ tests, the dart is thrown 500 times. The result shows that the number of darts lost falls from approx. 9% to approx. 5%. This, therefore, constitutes an improvement, but approx. 5% of the darts thrown are still lost.

A corresponding construction is known from UK Patent Application no. 2,039,755. Here, however, friction is used instead of spring power, so that the dart point can be moved from an extended position (the dart is thrown with the point in this position) , to a posi¬ tion where the point is moved a distance into the dart barrel, which occurs when the dart hits the tar¬ get. The point is thus moved under the influence of friction a certain distance towards the dart barrel, after which the dart barrel applies a hammer-like impact effect on the point, thus urging it into the target. This construction is presumably poorer than that which is known from English patent no. 1,541,886, the reason

being that the friction depends on many conditions such as wear, temperature, humidity etc.

None of the known constructions have been able to show any truly significant reduction in the number of darts which are lost for reasons of striking the steel wire.

The object of the invention is to provide a dart which does not fall to the floor when it strikes the steel wire, but which upon impact with the wire changes dir¬ ection and hits the actual target, and thus always re¬ main sitting in said target.

This is achieved by designing the dart according to the invention as presented and characterized in claim 1.

When the dart hits the target, the point of the dart is held in its foremost position in the barrel. Upon impact with the steel wire, the point will be pushed right back into the chamber and the dart continues al¬ ong the same trajectory, but now with a shorter point, and will thus hit the target one more time, but at a place which is shifted slightly. The reason for this is that a dart which is thrown at a target will always follow a parabolic trajectory, a so-called throw-para¬ bola. The length of' the trajectory will depend on the relevant player's throw curve, throwing height and technique. The dart, however, will never be able to hit the target at right-angles to the plane of the target, since this is always vertical. The dart accor¬ ding to the invention is therefore arranged in such a way that when it strikes the steel wire, the dart's trajectory is extended so that the dart hits twice in

the same throw, but the new hit will always be slight¬ ly displaced from the original hit on the wire. This displacement is sufficient to ensure that the dart always remains sitting in the target and never re- bounds .

The dart according to the invention is preferably de¬ signed as presented and characterized in claim 2, in that a simple construction is achieved which is rel- atively inexpensive to produce.

The dart according to the invention is preferably de¬ signed as presented and characterized in claim 3, in that the construction achieved has very few parts, and thus in a simple manner the dart can be arranged to allow the point to be moved a distance into the barrel by a suitable force depending on the dart's own weight. Normally, darts are produced with a weight of from 15 g to 35 g in steps of 1 g, and the force which is applied to the dart point and causes it to be moved freely into the bore can be changed in a simple man¬ ner, namely by merely changing the O-ring. If the characteristics of the dart should change after very frequent use, one can also simply change the O-ring whereby the dart regains the characteristics it had when new.

By constructing the dart according to the invention as characterized in claim 4, the dart provided will have quite definite aerodynamic characteristics, as opposed to the known darts where the point is dispos¬ ed in a resilient or frictional manner, in that the point in these known darts can be displaced when thrown very hard. With the dart according to the in-

vention, such a displacement of the point of the dart in connection with the throw is impossible.

If the dart according to the invention is constructed as characterized in claim 5, one can change the char¬ acteristics of the dart as required or, after having made a number of trial throws, one has obtained pre¬ cisely that displacement length which gives the best results in connection with the precise way in which one throws.

Claims 6 and 7 present advantageous ways in which the setting of the length of the point's displacement can be carried out.

The invention will now be described in more detail with reference to the drawing which shows a preferred embodiment of the invention, and where

fig. 1 shows a dart according to the invention in cross-section, and fig. 2 shows a slightly different form of the actual point.

A dart according to the invention is shown in fig. 1- of the drawing, the dart being shown with the dart barrel 10 and the shaft 6 cut through in a plane sec¬ tion.

In the barrel 1 0 , which is elongated and of the same outer form as the generally-known darts , there is a thread 5 at the rear end by means of which a normal flight shaft 6 is secured. The shaft 6 is of the commonly-known type , for example of plastic , nylon , metal or a combi-

nation hereof. The shaft 6, and the feathers secured herein but not shown, do not form part of the inven¬ tion and will not be described further.

The dart barrel 10 has an elongated, central chamber, for example a bore 12, which is open at the front end of the barrel in the direction of throw. The bore 12 is narrowed down at the foremost end, thus enabling a point 1 to be secured. The one end of the point which is held in the bore 12 has a thick portion, e.g. a spherical portion 2, so that the point 1 cannot be drawn out through the front end of the barrel. The * thick portion 2 of the point is secured in the posi¬ tion shown in the drawing by means of an O-ring 3 or another frictional element. The O-ring 3 is fitted, for example, in an internal annular groove 11 in the barrel 10.

When the dart hits the target - that is not the steel wire on the target - the point remains in the position shown in the drawing until it sits firmly in the tar¬ get. It is not until after this time that the mass of the barrel will cause the spherical part 2 of the point to pass the O-ring 3.

Upon impact with- the. steel wire, the weight of the barrel 10 will cause the point's spherical part 2 to be pressed through the hole in the O-ring 3 immed¬ iately, after which it is free to move in the long- itudinal direction in the bore 12. Consequently, the dart is actually given a shorter point, shortened namely by the length 7, in that the double arrow 7 indicates the amount by which the point can be moved. Immediately hereafter, a new hit is made, but because

of the arc of the traj ectory, the point of the dart is given a new point of impact with respect to the target . The length 7 is in the order of 6-15 rrm, preferably approx. 10 mm.

In this construction, the point 1 is very easy to change if it is damaged, and no parts can be assembled incorrectly.

In fig. 2 is shown a dart point 1 with a rounded end part which is slightly different. The end part 13 is produced by securing the point and working the end part in a hammer-like manner to create a thick por¬ tion, which is then machined to form a rounded-off friction area 13.

In the bore 12 is disposed a setting element 4 with ^• a limiting surface 8 for the movement of the point 1. The setting element 4 can either be replaced by anoth¬ er, or be disposed in the core in a movable manner, e.g. by means of a thread or friction, thus enabling the movement possibility 7 of the point to be changed or adjusted completely as required. The setting ele¬ ment 4 is made of a suitable material, e.g. plastic or metal, in that consideration must be given to the fact that its weight forms part of the weight of the dart.

The surface 9 on the barrel 10 can be machined in the same way as the commonly-known darts, e.g. by profil- ing, knurling or quite smooth and shiny. The barrel 10 is normally made of metal or metal alloys such as nic¬ kel, tunsten, brass or similar materials with suitable weight and workability.

The O-ring 3 is an ordinary O-ring, of rubber, plastic or synthetic material, and the point 1 is made of steel or hardened metal alloys. The O-ring is lubrica¬ ted with a suitable lubricant, for example acid-free vaseline or vaseline with a silicone content.

During trial throws with the dart according to the invention and with a commonly-known dart, it proved that the dart according to the invention fell to the floor only 1 time per 1000 throws, while the known dart fell 97 times per 1000 throws. The dart accord¬ ing to the invention thus shows a truly significant progress towards the total avoidance of the loss of darts which strike the steel wire on the target.