US2501218A - Electric dart board - Google Patents

Description

March 211, 1950 J. H. HILL ELECTRIC DART BOARD Filed June 24, 1948 3 Sheets-Sheet l INVENTOR: Jo/mfiarzyflzli, B) W W @MQMQ 6 A TTORN E YS March 23, 1950 J. H. HILL ELECTRIC DART BOARD 3 Sheets-Sheet 2 Filed June 24, 1948 WITNESSES I /QMZWM INVENTOR Jn/z/zHar/y ATTORNEYS March 21, 19 50 J. H. HILL Q 2,501,218 ELECTRIC DART BOARD 7 Filed June 24, 1948 3 Sheets-Sheet 3 Z/WITNESSES .Jl lg EN 7! Z621? I {I 0 12 any 2 @fi 70 W 7 y W A TTORNEYS.

Patented Mar. 21, 1950 ELECTRIC DART BOARD John Harry Hill, Pennsauken Township, Camden County, N. J.

Application June 24, 1948, Serial No. 34,949

6 Claims.

This invention relates "to an electric indicating game board, and more specifically relates to an electric indicating dart'boardconstructed in part of novel replaceable segments of laminar structure.

Various indoor and outdoor target games, such as darts, archery, gunnery and the like have been made more enjoyable by providing electric indicating target areas. "In the'target, each scoring area may be wired so that the impact of the missile or projectile on the area will cause a designated'light to become illuminated and thus indicate visually the scoring area that the player has hit. Similarly, various horns, bells, or other audible signals may-be actuated by the impact of the missile. In games employing sharppointed missiles such as-darts, knives and arrows which pierce the surface of the target, methods have been devised for utilizing the -metal point and shaft of the missile to close an electrical circult and actuatea visual or audible indicator. For example, targets have been constructed of layers of metallic foil or screen separated by a layer of insulating wax such as melted paraffin or beeswax, eachlayer of metal being connected to one terminal of the indicator.

The foregoing mechanisms have presented many difficulties and disadvantages. The employment of an insulating wax and metallic foils have made it necessary 'to surround each responsive or indicating area on the target with an unwired and non-indicating area. In such devices the non-indicating-area is necessarily of substantial size in order to keep the indicating area electrically separate. This has limited the application of theidea to-target areas of simple design, such as a small number of concentric rings of which only alternate rings would respond to-the piercing action of the metal shaft and actuate the indicator. A further disadvantage of the methods employed in the past is that the'surface particles ofthe dart board. are rapidly pulverized and torn until one segment or local area of the entire target surface becomes worn through. This,-of-course,'renders the entire target incapable of further use and the whole target must be discarded while only a small area such as the "bulls-eye is worn out. This is wasteful even in the'case of relatively inexpensive, non-indicating dart boards. The waste would be greatly magnified when the board is specially constructed, wired and fitted with a large number of lightsand sockets. The-use of the wax and metal-foil layers tends further to increase the rate of wear by reason of plasticity,

structuralweakness, and low resistance to tear. Another disadvantage is that systems employing metallic foil and wax have exhibited relatively poor dart retentivity. By this I mean that when a dart is imbedded in the layers of foil and wax, a certain amount of permanent deformation takes place and produces a void space when the dart is removed. A subsequently thrown dart which impinges upon the same point will sometimes not be retained in the target at all and at other times the dart will hang so loosely at the targetsurfacethat it will not provide an electrical contact between the layers of metallic foil.

It is therefore one object of the present invention to provide an electric indicating dart board with a highly durable penetrating surface, providing a positive dart-retention. A further object is to provide sucha dart board which doesnot contain paraffin or beeswax.

It is a further object of this invention to provide an electric indicating dart board in which individual area elements of the target surface may be replaced rapidly and inexpensively.

A still further object is to'provide an electric indicating'dart board in which any point in'the entire target area willrespond to the penetration of a dart andindicate visually or audibly which scoring area the dart has penetrated, with no"dead or non-indicating areas on the target.

Still another object of-the invention is to provide an electric indicating dart board that has an indicating target-area made up of large numbers of adjacent scoring area segments of varying shapes and sizes, allof which are electricallyindicating.

Other objects and means for carrying them into effect will be apparent from the following description of the present invention and from the accompanying drawings wherein:

Fig. l is a face viewof an embodiment of an electric indicating dart board. 7

Fig. 2 is a sectional view on line II--1I through Fig. 1.

Fig. 3 is a fragmentary enlarged face view of the target area as indicated by the arrows III-III of'Fig.i2.

Fig. 4 is a sectional view on line IV-IV of Fig. 3.

Fig.5 is an exploded view showing the different parts oi'an inner segment. of the target'area.

Figffi is awiring diagram showing an electrical circuit that-may be used in the embodiment of Fig. 1.

"In order to understandthe invention, reference should first be had to Fig. 1 which shows the target face of a preferred form for this invention. While the invention obviously embodies a wide variety of designs, the aforementioned specific design serves as a convenient illustrative example. Rigidly mounted in the face of the board, there are twenty equal-sized scoring areas H which are grouped around a central circular area or bulls-eye I2 and which are outlined by radial lines 2 intersecting a circle concentric with the central circle. These triangular areas H I call the inner segments. The concentric scoring ring at the outer edge of these inner segments is also divided by the radial lines into twenty scoring areas of equal size, and I call those areas E9 the middle segment. Similiarly, the twenty segments 9 beyondthe middle segments are called the outer segments. Beyond the set of outer segments is a foul ring 83 which is not cut by the radial lines and which constitutes one undivided foul field area. Thus it may be seen that this design contains 62 separate scoring areas, each of whichhas a scoring response independent of the others and is replaceable independently of the others without dismantling the dart board.

In constructing the novel segments of this invention, a laminar structure of Bakelite, wood, cork and sprayed metal is employed. It will be understood that the bulls-eye, the inner, middle, and outer segments, and the foul field ring are of similar construction, the principal difference in construction being merely in the size and shape of the segment.

The various layers of which I build an inner segment are shown in Fig. 5. The inner segment base 32 is made of Bakelite or the like and is cemented to the back surface of conforming wood part 3|. Two hollow center clamping screws 25 are firmly secured in base 32 with their heads flush with part 3| and with their threaded shafts projecting through the back of the segment. Wires 29 and 36 for connecting into the electrical circuit hereinafter described are threaded through the hollow centers of the clamping screws. According to an especially convenient embodiment the wire inside the hollow center of the clamping screw is left bare. When the hollow space within the clamping screw is filled with solder, the entire clamping screw becomes the electrical conductor and there are no loose wires to be connected. When the segment is installed in the dart board, contact clamping nuts 2i? (Fig. 4) serve as electrical conductors and as means of mechanical attachment at the same time. Mounting piece 3! is a properly-shaped wood, Celotex, or porous segment, made preferably of white pine about thick. It is provided with a hole through which wire 29 is threaded, and a somewhat larger hole fitted with an insulating tube 26 for wire 30. In the next step, a thin layer of cork 33, with corresponding holes for wire 29 and tube 26, is attached firmly to mounting piece 3! by cementing, gluing or the like. The strands of wire 29 are separated and distributed flat in a fanwise fashion upon the outer face of cork 33 as shown in Fig. 3. The strands are then pressed mechanically against the face of the-cork so as to imbed the wires in the porous surface to a certain extent and to give them a tendency to remain in place. A spray metal, of which zinc is an excellent example and will be used for purposes of description, is then impinged upon the entire outer cork surface of element 33 and upon the flared strands of fine wire 29. While zinc has been used as a preferred metal in this description, it is of course clear that many other metals such as copper, tin, lead, aluminum and 1611' alloys may be employed and that various methods of metal spraying may be followed to attain a substantially uninterrupted porous metallic contact layer. For a satisfactory method of spraying metals, reference is hereby made to the U. S. patent to Schoop, No. 1,128,058.

When the finely divided metallic spray strikes the pore-surface of the cork, the minute particles of metal distribute themselves within the irregular cavities of the corkboard pore-structure and penetrate the surface of the cork. The metal solidifies within the interstices of the porous surface, and further quantities of metal which follow build a smooth and continuous metallic surface which is securely bonded to the cork surface and to the strands of wire 29. The zinc spray is continued until a substantially uninterrupted zinc layer approximately .002 inch thick is obtained. This porous layer will usually be thick enough to cover the cork smoothly while the exposed conducting wires are only partly covered. The zinc spray is followed by a spray of finely divided metallic copper to form a second porous layer having a thickness of about .002 inch. This layer is shown at 34 in Fig. 5 and is hereinafter referred to as the inner metallic contact layer. On contacting the zinc surface, the hot finely divided copper spray locally melts particles of zinc and forms a copper-zinc alloy at the interface. The interfusing and alloying of the metals joins the two metallic layers with the result that a tenacious metallic bond is obtained on cooling and solidifying.

Upon completion of the double metallic layer, a second cork layer 35 with a single hole for insulator tube 26 is attached to the exposed copper surface by cementing or gluing, preferably with the aid of mechanical pressure. The second wire 30 is threaded through the hole in the insulating tube 26. The insulating tube has the function of keeping the two metallic layers electrically separate since in the absence of such a tube, wire 30 would be likely to contact the first metal layer and short-circuit the segment.

The free ends of wire 30 at the outer surface of the segment 35 are spread fanwise and compressed against the cork. After the resulting surface is sprayed with zinc and then with copper as before, the metal surface hereinafter referred as the outer metallic contact layer is covered with a third cork layer 28 which is cemented firmly and makes up the outer surface of the segment. The construction of the layers in a finished inner segment will be seen in Figs. 3 and 4. In the inner segment I! there shown, 33 is the lower cork layer and 34 depicts the metal to cork layer after the metal spray treatment. Fine wire 29 is shown as spread out on the face of the cork and covered with the spray metal. Fine wire 30 is spread on middle cork layer 35 which is covered with metal as shown at 36. Metallic layer 36 is then covered with face cork 28 and the segment is completed by affixing insulating band 31 to the vertical surfaces as indicated in Figs. 3 and 5.

The method of operation of the dart board will now be understood. When the inner metallic contact layer Wire 29 is connected through an indicating means such as a light, horn or hell to one side of a source of electric power such as a battery or an alternating current source and the outer metallic contact layer wire 30 is connected directl'y'to the other terminal of the power source.

'the indi-cating means will not be energized because the two metal layers of thesegment are electrically insulated. However, whena sharppointed missile such as a knife-ora dart penetrates sufficiently far into the segment, it makes 'an electrical contact with layer-'36 andwith layer 3], closing the electrical circuit and actuating the indicatingmeans. When the missileis removed, the circuit is opened and the indicating'means is disconnected.

1n the foregoing manner, twenty inner segments are made up. Following the sameprocedure, twentymiddle segments and twenty outer segments are fabricated in appropriate shapes.

Similarly,the bulls-eye l 2'and'the foul ring 8 "are made up. The individual parts are then :ready to be mounted to thebase of the dart board.

The configuration of the base of the board is of course subject to wide variation depending upon the type of game board'to be used-and the -manufacturing steps found to be most convenient and economical. An excellent "base of this type may be made in accordance with the design-shown in Fig. 2.

'Mounting board I, which is preferablymade of wood'such as white pine, is provided with suitable 'openings for light sockets and connections, and is provided with an outer moulding -2, made of hardwood. A spacer strip 3 and a back inclosure panel 4 are included to provide space for the electrical connections and wiring. Core base 5 is :drilled at the designated points for entry of the clamping screws 25 from each'individual segment and for their respective clamping nuts 20.

Since the position of each hole should be precise in order to insure a tight fit of all segments, the

"core base should be laid-out and drilled with due erably brass. Separation at the bulls-eye is attained by means of the metallic bushing l3. These separation elements may be combined in the form of a grid which is fixedly mounted in board 5 by means of elements l3, l4. l5 and it which extend into board 5 as shown.

When the mechanical parts of the apparatus have been fully assembled, there remains only the relatively simple matter of connecting the unit electrically which may be accomplished as indicated in the wiring diagram of Fig. 6.

The electric lights which respond to the penetration of the target area may of course be placed in any manner that is found to be desirable or pleasing to the eye. One satisfactory configuration of lights appears in Fig. 1. In this configuration, it will be found desirable to make the electrical connections in such a manner that the inner circle of lights corresponds to the inner segments, the middle circle of lights corresponds to the middle segments, and the outer circle of lights corresponds to the outer segments. Special lights 2| and Zia may be provided to denote a hit in the bulls-eye or in the foul ring respectively and lights 22 may be used to indicate a flow of current in the dart board circuit.

The foul field ringis similarly secured in The indicating lights that may be usediin connection with the game board are conveniently connectedasshown in Fig. 2. Light socket and bulb l8 are recessed inthe mountingboardcand seatedby means of fiber bushing l. Thelights may allbeprotected from dartlbreakage by thick transparentiLucite inserts 6 .or'by .othersuitable means.

The wires projecting from the backs of the segments maybe connected in accordance withsthe wiring diagram in Fig. 6. It will be seen thatthe completion of each target area lighting circuit depends only uponthe electrical connection be tween the inner and outer metallic layers of the target face. The connection is of course supplied by's'themetallic or other electrically-conducting penetrating shaft. Sincethe lights are preferably of theilow voltage type and the customary powertsourcecis of ahigher voltage, transformer vtil has'been included in the circuit. Of course, the circuit may be a. direct-current battery circuit orotherqcircuit'if desired.

In .the practiceof this-invention, each segment must of course be kept electrically separate from the neighboring'segments. This I have accomplished by'covering the side areas of each segment with athin (.003") plastic film 31 as shownin Figs. 3,-4 'and 5 using a commercial material called Artus Plastic Stock which is manufactured by Industrial Products Suppliers, New York, New York. The insulation may otherwise be provided by applying similarly thin coatings 'of rubber or other non-conductors the nature 'of which will readily occur to persons skilled in the'art.

Insulation between segments may also be efiected by using non-conducting compositions as'separator strips M, i5, i6, 24 and bushings l3. However, theedges-of any nonconductor so used will be exposed to the force of thrown darts, and the material must therefore be capable of resisting the 1 mechanical abrasion and penetrating and tearing forces exerted by the darts.

The specific metal contact layer made up'of a double spray of zinc and copper as above tie-.-v scribed is particularly effective and durable. 'The zinc coat forms a tenacious adhesive bond with the cork, while the copper layer is an excellent electrical contact surface and contributes materially to the flexibility and strength of the metallic layer and to the strength of the entire penetrated surface. As contrasted with a plain corkboard or a board containing layers of metal foil, the product of this invention has the property of excellent dart retentivity. The presence of the layers of sprayed metal provides a substantially stable penetrating base for trapping the metal shaft of the missile and holding it in position. The adaptation of the metal to the porous structure of the adjacent cork produces a yielding and flexible penetrating surface which suffers little permanent deformation on being penetrated by a dart, and which has excellent wear-resisting qualities. The provision of sprayed metal layers F affords a compact, coherent segment that holds its shape even better than plain corkboard, thus allowing the construction and use of replaceable segments.

It is clear that the use of a replaceable segment made of materials that deform after hard usage would be fruitless; yet without the feature of replaceable segments the rapid wear of a few local areas of the board would require premature discard of the board and would make the cost of replacement prohibitive.

I claim:

1. A replaceable dart board segment comprising an inner layer of cork, an inner metal stranded wire the strands of which are distributed against the surface of said cork, an inner metallic layer made up of a preliminary zinc layer conforming to the irregularities of the cork and the wire strands and a subsequent layer of copper bonded to the zinc layer, a middle cork layer, an outer metal stranded wire the strands of which are distributed against the surface of the middle cork, an outer metallic layer made up of a preliminary zinc layer conforming to the irregularities of the cork and the wire strands and a subsequent layer of copper bonded to the zinc layer.

2. In an electric dart board a base member and a plurality of electrically insulated, unitary, replaceable segments removably connected thereto, each of said unitary segments comprising, in fixed relation, a segment base, a dart receiving element affixed to said segment base, a non-conductive, porous layer attached to said dart receiving element, an inner metallic contact layer integral with and conforming to the irregularities of said porous layer, a middle porous layer overlying said inner metallic contact layer, and an outer metallic contact layer affixed to the upper surface of said middle layer, the pores of said porous layers being substantially penetrated by the metallic contact layers.

3. In an electric dart board the combination of a base member and a plurality of the segments of claim 1 removably attached thereto.

4. A unitary replaceable dart board segment comprising an inner layer of a porous, non-conductor of electricity, an inner stranded electrical conductor the strands of which are distributed against the face of said porous inner layer, an inner porous metallic layer bonded to said porous non-conductor and conforming to the irregularities thereof and conforming to the irregularities of the strands, a middle layer of a porous nonconductor of electricity, an outer stranded electrical conductor the strands of which are distributed against the face of said porous middle layer, and an outer porous metallic layer bonded to the middle porous non-conductive layer and conforming to the irregularities of the inner porous layer and conforming to the irregularities of the strands.

5. A unitary replaceable dart board segment comprising a segment base and a series of alternate layers of electrical insulators and electrical conductors, all of said layers and the segment base being attached together to form a stable unit, one of said electrical insulators being a porous material and one of said electrical conductors being a porous metal bonded by penetration to said porous material. r

6. In an electric dart board, a unitary replace able segment comprising a segment base, a porous surfaced cork layer affixed to said segment base, a sprayed metal layer adhering to and penetrating the irregularities of the cork surface of said cork layer, an electrically non-conductive layer on said sprayed metal layer, an electrically conductive layer on said electrically non-conductive layer, an electrical conductor connected to said sprayed metal layer and another electrical conductor connected to said electrically conductive layer, each of said conductors passing through said segment base, whereby a conductive missile penetrating the sprayed metal layer and the electrieally conductive layer connects said conductors electrically. I

JOHN HARRY HILL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,057,677 Shaw Apr. 1, 1913 1,164,008 Moore Dec. 14, 1915 2,168,644 Browning Oct. 14, 1936 2,330,202 Brennan Sept. 28, 1943 FOREIGN PATENTS Number Country Date 439,172 Great Britain Nov. 26, 1935

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