U.S. patent application number 11/199099 was filed with the patent office on 2007-02-08 for locker dart game system.
This patent application is currently assigned to LockerMate Corporation. Invention is credited to Thomas Charles Herrmann.
Application Number | 20070029732 11/199099 |
Document ID | / |
Family ID | 37716952 |
Filed Date | 2007-02-08 |
United States Patent
Application |
20070029732 |
Kind Code |
A1 |
Herrmann; Thomas Charles |
February 8, 2007 |
Locker dart game system
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) |
Correspondence
Address: |
BECK AND TYSVER P.L.L.C.
2900 THOMAS AVENUE SOUTH
SUITE 100
MINNEAPOLIS
MN
55416
US
|
Assignee: |
LockerMate Corporation
|
Family ID: |
37716952 |
Appl. No.: |
11/199099 |
Filed: |
August 8, 2005 |
Current U.S.
Class: |
273/348.3 ;
273/407; 473/570; 473/578 |
Current CPC
Class: |
A63B 65/02 20130101;
F41J 3/0057 20130101; F42B 6/003 20130101; A63B 2209/08 20130101;
A63B 67/00 20130101 |
Class at
Publication: |
273/348.3 ;
473/578; 473/570; 273/407 |
International
Class: |
F41J 3/00 20060101
F41J003/00; A63B 43/06 20060101 A63B043/06; F41J 1/10 20060101
F41J001/10; A63B 65/02 20060101 A63B065/02 |
Claims
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
[0001] 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
[0002] 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.
[0003] 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.
[0004] 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.
[0005] 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).
[0006] 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).
[0007] 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
[0008] 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.
[0009] 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.
[0010] 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.
[0011] 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
[0012] FIG. 1 is an isometric drawing of several lockers, one of
which contains the present invention.
[0013] FIG. 2 is an isometric drawing of a prior art magnetic
dart.
[0014] FIG. 3 is an isometric drawing of the magnetic dart of the
present invention.
[0015] FIG. 4 is a longitudinal view of a dart of the present
invention showing details of the nose section and the tail
section.
[0016] FIG. 5 is a longitudinal view of the dart of the present
invention illustrating various dimensions.
[0017] 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
[0018] 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.
[0019] 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.
[0020] 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.
[0021] 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.
[0022] 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.
[0023] 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.
[0024] 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.
[0025] 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.
[0026] 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.
[0027] 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%.
[0028] 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.
[0029] 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.
* * * * *