Title:
Locker dart game system
Kind Code:
A1


Abstract:
Magnetic locker darts with a grip region of length equal to the width of a human thumb provide throwing accuracy while minimizing contact with other locker contents. The target is a decal that can be attached to the inside of a metal locker door or other metal appliance.



Inventors:
Herrmann, Thomas Charles (Chaska, MN, US)
Application Number:
11/199099
Publication Date:
02/08/2007
Filing Date:
08/08/2005
Assignee:
LockerMate Corporation
Primary Class:
Other Classes:
273/407, 473/570, 473/578
International Classes:
F41J3/00; A63B43/06; A63B65/02; F41J1/10
View Patent Images:
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Primary Examiner:
GRAHAM, MARK S
Attorney, Agent or Firm:
Beck, And Tysver P. L. L. C. (2900 THOMAS AVENUE SOUTH, SUITE 100, MINNEAPOLIS, MN, 55416, US)
Claims:
What is claimed is:

1. 1.A dart comprising: a) a magnet; b) a nose section containing i) a tip retainer having a first diameter and a hollow portion containing the magnet; ii) nose barrel having a second diameter less than the first diameter, and iii) a nose taper running from the first diameter adjacent to the tip retainer to the second diameter adjacent to the nose barrel; c) a barrel, having an axis, a tip end within the nose barrel of the nose section and a tail end; d) a plurality of fins attached to the tail end of the barrel, the fins having a first section closest to the tip end of the barrel, the first section extending from the barrel to a radial distance from the barrel axis equivalent to one half of the first diameter; wherein a grip section is defined between the nose taper to the first portion of the fins; and wherein the length of the grip section is approximately 22 millimeters.

2. The dart of claim 1, wherein the magnet is a rare-earth magnet.

3. The dart of claim 2, wherein the overall length of the dart is approximately 59 millimeters.

4. The dart of claim 3, wherein the ratio of the overall length of the dart to the length of the grip section is between 2:1 and 3:1.

5. The dart of claim 1, wherein the magnet is a rare-earth magnet in the form of a right circular cylinder having an axis coincident with the axis of the barrel.

6. The dart of claim 1, wherein the first diameter is approximately 11 millimeters and the second diameter is approximately 7 millimeters.

7. The dart of claim 1, wherein the grip section is between 20 millimeters and 24 millimeters.

8. A magnetic dart, comprising: a) a dart axis; b) a rare-earth magnet in the form of a right circular cylinder having an axis coincident with the dart axis and a diameter of between 6 and 12 mm; c) a radially symmetrical one-piece metal nose section divided proceeding tail-ward into a tip retainer, a nose taper, and a nose barrel, wherein the magnet is held and partially enclosed by the retainer, and the nose barrel is hollow, and wherein the length of the nose section is between 16 and 22 mm; d) a one-piece plastic tail section having a length between 33 and 45 mm, comprising an axially symmetrical and essentially solid stem and 4 radial fins equally spaced azimuthally, wherein the stem is divided proceeding tail-ward into a tail barrel segment that is partially inserted into the nose barrel segment and an essentially conical tail barrel taper, and each fin is divided proceeding tail-ward into a fin expansion segment, a fin mid-segment, and a fin contraction segment; and e) a grip region having a length between 16 and 29 mm including the nose taper, the nose barrel, and the portion of the tail section that is tip-ward of the fin mid-segment.

9. A magnetic dart game system, comprising: a) a dart having a blunt magnetic tip and a grip area, the overall length of the dart being less than 71 mm and ratio of the length of the grip area to the overall length of the dart being between approximately 1:2 and 1:3; and b) a target containing essentially no ferromagnetic material; and c) a surface of a locker made essentially of ferromagnetic material, to which the target adheres so as to allow the target and the locker surface to receive and retain the dart.

10. The magnetic dart game system of claim 9, wherein the target is a printed plastic decal that adheres to the locker surface by static electricity.

11. The magnetic dart game system of claim 9, wherein the target is a printed plastic decal that adheres to the locker surface by an adhesive.

12. The magnetic dart game system of claim 9, wherein the dart and the target are sold in a package that contains no ferromagnetic material to which the target could be attached to receive and retain the dart.

Description:

FIELD OF THE INVENTION

The present invention relates generally to locker accessories. More particularly, it relates to a dart game including darts designed for use with a metal locker and a target decal that can be attached to a locker door.

BACKGROUND OF THE INVENTION

A dart game system consists of darts and a target. The target is partitioned into regions and is marked with symbols, allowing users to play various games involving throwing the darts at the target. The regions of the target have meaning of significance within those games adapted to a particular target layout. A player attempts to excel by throwing her darts so that they stick to regions of the target associated with high scores within the context of the game at hand.

A variety of different target layouts and games have been created. All the games emphasize accuracy in throwing the darts at specific regions of the target. The target is typically mounted or printed on the surface of a dart board. Classical dart boards used in taverns are made of cork, straw, or paper.

According to the official rules of the World Darts Federation, “darts . . . shall not exceed an overall length of 30.5 cm, nor weigh more than 50 grams. Each dart shall consist of a needle shaped point which shall be fixed to a barrel. At the rear of the barrel there shall be attached a flighted stem, which may consist of separate parts.” (WDF Playing and Tournament Rules, 6th Rev. Ed., Dec. 1, 2003) Historically, the flighted stem contained feathers, which have been replaced in many modern darts with fins. Each fin or feather is approximately planar, with the plane of each fin including the common centerline of the barrel and the point. The metal point at the tip of the dart sticks to the target by penetrating through the surface into the fabric of the underlying board.

Needle-nose darts can cause injuries to the players, bystanders, the wall on which the board is mounted, or other nearby objects. This safety consideration has led recently to a variety of new materials and designs for dart/target combinations in which the sharp points are replaced by flat surfaces. Many of the new game systems use darts with tips that consist wholly or partially of magnets. The magnet tips cause the darts to stick to surfaces that contain ferromagnetic material. According to the American Heritage Dictionary, “ferromagnetic” is defined as: “Of or characteristic of substances such as iron, nickel, or cobalt and various alloys that exhibit extremely high magnetic permeability, a characteristic saturation point, and magnetic hysteresis.” Ferromagnetic material has the capability of being turned into a magnet, but which might not itself be magnetic. Magnetic darts sometimes employ dart tips that are rare-earth magnets, which are significantly stronger than more common iron magnets (e.g., Jonsson, U.S. Pat. No. 5,775,694; Gittens, U.S. Pat. No. 5,613,694).

Some magnetic darts, such as those described by Kettlestrings (U.S. Pat. No. 4,119,316) and Seymour (U.S. Pat. No. 6,062,997), differ significantly in both shape and structure from traditional needle-nose darts, because they are designed for use primarily by children. But many magnetic darts retain the traditional elongated barrel and flighted stem design (e.g., Jonsson, U.S. Pat. No. 5,775,694).

Prior art magnetic dart game systems contain a target board including either a rigid layer of magnetic material or a relatively rigid rubber layer impregnated with magnetic material. Jonsson (U.S. Pat. No. 5,775,694) suggests covering a board that includes magnetic material with a printed plastic decal target, attached to the board with an adhesive, which is easy to remove from the board

SUMMARY OF THE INVENTION

The present invention dart game consists of magnetic darts and a matching target designed for use in a metal locker, such as those commonly found in a school or an athletic facility. A locker has very limited space for the occupant to store possessions. A prior art magnetic dart has a barrel of length approximately equal to that of typical traditional pointed darts. Such a long dart, sticking to a target mounted on the inside of a locker door, will protrude unnecessarily far into the interior volume of the locker when the door is shut. As the locker door is being closed or opened, the dart can come into contact with other locker contents—coats and other clothing, books, athletic gear, footwear, and shelves. In consequence, the dart may become dislodged and fall, or might even disturb other items stored in the locker. From this standpoint, darts smaller than those of the prior art are generally preferable as locker darts.

On the other hand, the skill in every dart game consists of accurately targeting the darts, so a dart should have a barrel length large enough to fit conveniently within a human hand. These two opposing length scale considerations suggested to the inventors the ideal size of the magnetic locker darts described herein, having a central barrel portion (i.e., between the retainer enclosing the magnetic tip and the fins) that just comfortably fits between an adult's thumb (having a width of approximately 24 mm) and forefinger. The dart of the preferred embodiment of the present invention has a length of about 50 to 70 mm.

Because of its short length and strong magnetic tip, a locker dart can be helpful for purposes other than dart games. In a manner analogous to tacks on a message board, a dart can be used to post a sheet of paper, fabric, or other thin material on the inside of the locker door or elsewhere within the locker. The posted material is held between the magnet tip of the dart and the metal surface of the locker. Alternately, a lightweight article, such as a pair of swim goggles, can be hung from a dart, where the dart so employed serves as a peg.

One aspect in which the locker darts game system of the present invention differs from the prior art is that it includes a target but no board. Its target contains essentially no metal or metal-impregnated surfaces or layers. Instead, the system takes advantage of the magnetic material present in a locker door, external to the product itself, to attract the magnetic dart tips. The target is printed on a thin sheet of plastic material. Once a backing is peeled off, the plastic sheet will adhere to a locker surface, by static electricity in the preferred embodiment. Of course, the target will also stick to various other objects having relatively smooth metal surfaces, such as some refrigerator doors and clothes washers, providing alternative environments where the darts game can be played.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric drawing of several lockers, one of which contains the present invention.

FIG. 2 is an isometric drawing of a prior art magnetic dart.

FIG. 3 is an isometric drawing of the magnetic dart of the present invention.

FIG. 4 is a longitudinal view of a dart of the present invention showing details of the nose section and the tail section.

FIG. 5 is a longitudinal view of the dart of the present invention illustrating various dimensions.

FIG. 6 is a longitudinal view showing how the geometry of a dart of the present invention relates to gripping the dart with a human hand.

DETAILED DESCRIPTION OF THE INVENTION

The locker dart game of the present invention is used within a locker 100 made of ferromagnetic material such as steel or iron. FIG. 1 shows a row of such metal lockers 100, one with an open door 110. Attached to the door 110 is a target 700 decal. A locker dart 300 is stuck to the target 700 (or more precisely to the door 110 behind the target 700). Two other locker darts 300 are being used to post a slip of paper 120 to the inside of the locker door 110. The locker door 110 is typically steel, a ferromagnetic material.

FIG. 2 illustrates a typical prior art magnetic dart 200. It preserves much of the look and feel of a competition needle-nose dart, including a tip 210 and an elongated barrel 220 that terminates in a flighted stem 230. The length of the prior art dart 200 shown is 100 mm (3.9 inches). The magnet tip 210 is a rare-earth magnet. Rare earth magnets have significantly stronger magnetic properties, and retain their magnetic properties better after repeated collision impacts, than ferrite magnets, which are more conventional. The feathers 240 of the flighted stem 230 are plastic fins 240.

FIG. 3 shows the locker dart 300 of the present invention. Like the prior art magnetic dart 200, it has a rare-earth magnet tip 310, a barrel 320 ending in a flighted stem 330, and fins 340. The most significant difference in the locker dart 300 of the present invention from the prior art magnetic dart 200 is its substantially shortened barrel 320.

FIG. 4 is an longitudinal view of the locker dart 300 in the preferred embodiment of the present invention. The dart is fabricated from three components: the magnet tip 310, a metal nose section 400, and a plastic tail section 410. The nose section 400 is divided longitudinally into three axially symmetrical segments: a hollow tip retainer 420, a nose taper 430, and a hollow nose barrel 440. The magnet tip 310 is bonded by adhesive within the tip retainer 420 (as shown with dashed lines in the figure), with a thin portion protruding at the tip whereby the dart can stick magnetically to ferromagnetic material. The tail section 410 consists of a stem 330 and four attached fins 340. The stem 330 is divided into a tail barrel 450, the tip-ward portion of which is bonded with adhesive to the inside of the nose barrel 440 (as shown with dashed lines in the figure); and a tail barrel taper 460. Each fin 340 is divided longitudinally into a fin expansion segment 470, a fin mid-segment 480, and a fin contraction segment 490. The barrel 320 consists of the nose barrel 440, the exposed part of the tail barrel 450, and the tail barrel taper 460.

FIG. 5 shows the important dimensions of the preferred embodiment. These are the diameter (9 mm) 655 of the magnet tip 310; the diameter (11 mm) 660 of the tip retainer 420; the diameter (7 mm) 665 of the nose barrel 440; the diameter (4 mm) 670 of the tail barrel 450; the width (13 mm) 680 of a fin 340; the radial dimension (26 mm) 675 of the tail section 410; the overall length (59 mm) 600 of the locker dart 300; the protrusion (1 mm) 620 of the magnet tip 310; the length (18 mm) 610 of the nose section 400; the length (39 mm) 605 of the (exposed) tail section 410; the length (4 mm) 640 of the tip retainer 420; the length (11 mm) 625 of the nose barrel 440; the length (7 mm) 650 of the cylindrical (exposed) portion of the tail barrel 450; the length (4 mm) 630 from the tail end of the nose section 400 to the start of the fins 340; the length (15 mm) 615 of the (exposed) stem 330; and the length (8 mm) 635 of the fin contraction segment 490. Variations of up to ±20% for those dimensions greater than 5 mm, and up to ±50% otherwise, are considered approximately the same as these measurements as that term is considered relative to this invention.

As illustrated by FIG. 6, the locations of the nose taper 430 and the fin expansion segment 470 have been separated just enough for a person to comfortably hold the dart 300 in that region, which constitutes the grip 500 of the dart 300. An adult thumb 510 has a width of about 20 to 25 mm, with a curved “pad” that matches the approximately curved surface provided by the combination of the nose taper 430, the nose barrel 440, the tail barrel 450, and the fin expansion segment 470. The 23 mm length 645 of this grip 500 is chosen to balance the need for a small dart 300 in the locker 100 environment with the need to be able to comfortably hold and accurately throw the dart 300. The overall length (59 mm) of the locker dart 300 (shown as length 600 in FIG. 6) is scaled to be equal to the length (23 mm) 645 of the grip 500 multiplied by approximately 2.5.

The shorter length of the locker dart 300 compared to the typical prior art dart 200 minimizes interference between the dart 300 and the contents of the locker 100 when the locker door 110 is being opened or closed. The rare-earth magnet tip 310 makes a single locker dart 300 sufficiently strong that it can be used to “tack” a sheet of paper 120 to an inside wall of the locker as illustrated by FIG. 1. The shorter length of the locker dart 300 also reduces the probability that the locker dart 300 will be accidentally dislodged. FIG. 1 also shows two locker darts 300 tacking slips of paper 120 to the inside of the door 110.

The shorter length (59 mm) 600 also improves the usefulness of a locker dart 300 compared to the prior art as a peg from which to hang things within the locker 100. Torque is the product of moment arm length (distance from a pivot axis) and force. An object of a given weight will apply more torque to a longer peg (i.e., dart) when suspended from its tail end than will the same object suspended near the tail of a shorter peg. Thus, a longer prior art magnetic dart 200 will only support a lighter suspended load, not to mention its increased likelihood of being dislodged by contact with other locker 100 contents. A locker dart 300 of the present invention can usefully suspend a lightweight object such as a pair of swim goggles.

These benefits are obtained by the present invention locker dart 300 having a grip portion of approximately 23 mm and a length of approximately 59 mm. With the term approximately being defined as ±20% for these dimensions, the grip can range from 18 mm to 28 mm, and the overall length can range from 47 mm to 71 mm. These extremes are optimally restricted so that the ratio of overall length to grip length remains between 2:1 and 3:1.

These length measurements are clearly dependent upon the definition of the “grip” for the locker dart 300. The above description defines the grip 500 as the area running from the nose taper 430 to the fin expansion segment 470 where a person naturally grips the locker dart 300. In FIG. 5, the length 645 of the grip 500 is shown from the beginning of the nose taper 430 to the end of the fin expansion portion 470. However, one can easily imagine a fin 340 design without a separation between the fin expansion segment 470 and the fin mid segment 480. In some circumstances, such as where there is no such separation, or where the separation between the fin expansion 470 and the find mid segment 480 occurs more than half-way through the length of fin 340, a different definition can be used to define the grip 500. In these circumstances, the grip 500 is still defined on one side by the nose taper 430 and the other side by the beginning of the fin 340 extending away from the tail barrel 450. More specifically, the length of grip 500 can be defined by the beginning of the nose taper 430 to that portion of the fin 340 that first extends away from the nose tail barrel 450 to the same radial distance as the tip retainer 420. In FIG. 5, this distance is 21 mm. Consequently, by subtracting a single millimeter from this dimension and adding a single millimeter to the previously determined grip length, it is clear that the present invention can be defined as a locker dart 300 having a grip portion between 20 to 24 mm, ±20%.

The target 700 of the present invention is divided into regions having meaning within the context of a dart game. The target 700 can be made of a sheet of thin plastic material, as in the current invention, or any other essentially non-magnetic thin material, such as paper or fabric. In the preferred embodiment, the target 700 is a plastic that adheres to the locker 100 surface by static electricity. It is also within scope of the invention for the rear side of target 700 to be coated with non-permanent, removable adhesive. The target is packaged with a removable and disposable backing layer, which when removed allows the target 700 to be applied like a decal to a surface of a metal locker 100. The present invention includes the target 700 in a package with the darts 300, but does not include any surface on which the target 700 can be placed. Functionality of the target 700 of the present invention requires a ferromagnetic metal surface external to the product, such as the inside of a locker door or, for example, the side of a refrigerator, washing machine, or filing cabinet to which the decal can be affixed.

The present invention is not to be limited to all of the above details, as modifications and variations may be made without departing from the intent or scope of the invention. Consequently, the invention should not be limited by the specifics of the above description, but rather be limited only by the following claims and equivalent constructions.