Abstract:
A flashlight apparatus includes a quantity of tritium within a transparent capsule for emitting light independently of any power source for helping a person locate the apparatus in the absence of substantial external light. The tritium glows in the dark for many years without any external power source. The apparatus also includes the conventional elements of a power source, a primary light source, a power circuit for electrical communication between the power source and the primary light source, a switch, and a housing containing the power source, the primary light source. The light source is preferably a light emitting diode, and may alternatively be an incandescent bulb. The light emitting diode is preferably a high intensity, low power consuming light emitting diode. The transparent capsule includes a vial containing the tritium, which capsule provides a virtually unbreakable enclosure.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application continues from a provisional patent application Ser. No. 60/116,259 filed Jan. 19, 1999, and claims the filing date thereof as to the common subject matter. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the general field of portable lighting devices and, more specifically, to a flashlight having substantially permanent luminescence not requiring an external energy source to stimulate the luminescence. It also optionally includes a housing sized to receive one or more batteries. One of the embodiments includes a square cross-section battery tube insert to fit into the housing to receive batteries smaller than the inside diameter of the housing to leave an annular floatation air space within the housing to make the flashlight buoyant. 
     2. Description of Prior Art 
     Ever since the invention of portable electrical storage batteries, it is been practical to carry around portable lighting devices which use incandescent bulbs as the light source. The most relevant reference that has been located is Pemberton, U.S. Pat. No. 4,546,416, which describes a flashlight in combination with phosphorescent material. However, the phosphorescent material must be rejuvenated by exposure to light at frequent intervals, a shortcoming overcome by the present invention because of its substantially permanent luminescence. Other prior art includes Pietruczynik, et al., U.S. Pat. No. 5,752,761, Sato, U.S. Pat. No. 5,757,111, McDermick, U.S. Pat. No. 5,842,777, McDermick, U.S. Pat. No. 5,161,879, Maglica, U.S. Pat. No. 5,260,858, Price, III, U.S. Pat. No. 4,843,526, Sharrah, et al., U.S. Pat. No. 5,853,241, et al., Maglica U.S. Pat. No. 5,836,672, Maglica, U.S. Pat. No. 5,528,472 and numerous other references. So far as is known no reference combines a flashlight with a substantially permanent luminescent housing. 
     SUMMARY OF THE INVENTION 
     Bearing in mind the foregoing, it is a principal object of the present invention to provide a flashlight that can always be located in the dark regardless of how long it has been there because of substantially permanent luminescence. 
     Another object of the invention is to combine those features with a flashlight that floats lens end up in water. 
     A further object of the invention is to combine the principal aspect of the invention with a lens which can be focused from a wide angle to a pinpoint of light, usually only when a single primary light source is used, such as a single incandescent bulb. 
     An additional object of the invention is to combine the principal aspect of the invention with a lens that is shatter proof. 
     Another object of the invention is to combine the principal aspect of the invention with the capability of using one or more low energy consumption, ultra bright light emitting diode(s) (LED) as an alternative to an incandescent bulb. 
     Another object of the invention is the to provide a flashlight having the foregoing characteristics with a slip proof grip. 
     Other objects and advantages will be apparent to those skilled in the art upon reference to the following descriptions and the accompanying drawings. 
     In accordance with a primary aspect of the invention, there is provided a flashlight including a power source, a primary light source, a power circuit connecting the power source to the primary light source, and a housing containing the power source and the light source and including a quantity of tritium within a translucent vial, which in turn is disposed within a virtually unbreakable protective transparent structure termed a capsule. The tritium within the capsule emits light independently of the power source to help a person locate the apparatus in the absence of substantial external light. 
     The light source is preferably at least one low energy consumption, ultra bright light emitting diode (LED), and may alternatively be an incandescent bulb. The LED is preferably a high intensity LED that achieves long duration from its battery power source by reason of its low energy consumption characteristics. The power source is one of several options: at least one larger diameter battery and at least one smaller diameter battery. The flashlight is offered in large and small battery diameter sizes, but the large diameter housing optionally includes a square cross-section battery tube that fits snugly within the housing inside diameter to define a floatation air space between the battery tube and the housing inside diameter. This makes the flashlight buoyant so it will float lens up. The apparatus preferably additionally includes a housing end wall. The housing is preferably formed of translucent material. 
     The apparatus preferably additionally includes a lens ring removably fitted to the housing. The apparatus preferably still additionally includes a tab of catalyst material secured within the housing for accelerating the neutralization of hazardous gaseous battery emissions. 
     The housing has an outer surface which preferably includes a series of rib projections for improved gripping in a user hand. The housing preferably has a external threads at one end thereof and the lens ring preferably has internal threads and are sized to fit and engagingly screw over the housing external threads. The apparatus preferably additionally includes an O-ring receiving groove in a portion of the housing outer surface and an O-ring fitted snugly into the O-ring receiving groove to create a watertight seal between the housing and the lens ring. The battery tube preferably has a square cross-section resulting in battery tube corners for abutting the housing inside diameter. 
     The capsule preferably includes two mating capsule halves at least one of which includes a recess in an interior face, the interior faces being fixedly attached to each other using one or more peg(s) and bore(s) to define one virtually unbreakable capsule. The capsule half having the recess provides a hollow within the capsule for snugly containing the vial of tritium. 
     The apparatus preferably additionally includes two loops of housing material extending from opposing sides of the housing and defining a region within the loops which each receive and fixedly retain one of the capsules. The power circuit preferably includes the power source, the light source, and a conductive metal strip embedded longitudinally in the housing. 
     A better understanding of the invention may be achieved by reference to the drawings in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the larger diameter flashlight of the first preferred embodiment. 
     FIG. 2 is an exploded side view of the larger diameter flashlight of FIG. 1, which contains C batteries, showing the lens ring, spacer ring, LED&#39;s and LED mounting plate, the two O-rings and the flashlight housing with O-ring grooves and opposing side loops containing tritium capsules. 
     FIG. 3 is a cross-sectional side view of the reflector used for the xenon incandescent bulb light source option. 
     FIG. 4 is a side view of the housing for the smaller diameter flashlight containing the AA batteries. This one is not buoyant because it lacks the annular floatation space. 
     FIG. 5 is an exploded view of the remaining elements making up the smaller diameter flashlight, including the lens ring, spacer ring, catalyst shown in broken lines, O-rings and LED. 
     FIG. 6 is a side view of the metal strip and battery spring making up most of the electric circuit. 
     FIG. 7 is an exploded perspective view of one of the capsules, showing the capsule halves separated and the vial of tritium positioned between them for containment within a hollow defined by the first half&#39;s recess. 
     FIG. 8 is a side view of the square battery tube. 
     FIG. 9 is a front view of the larger diameter flashlight with the lens, lens ring and light source removed, revealing the square battery tube fitted within the housing and containing AA batteries, also revealing the floatation air space around the battery tube. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     As required, a detailed embodiment of the present invention is disclosed herein. However, it is to be understood that the disclosed embodiment is merely exemplary of the invention which may be embodied in various forms. Therefore specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims to be later added and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. 
     Reference is now made to the drawings, wherein like characteristics and features of the present invention shown in the various figures are designated by the same reference numerals. 
     First Preferred Embodiment 
     FIGS. 1-3 disclose a flashlight with a luminescent housing in the form of a tubular housing  24  shown generally at  10 . Flashlight  10  contains a power circuit  30  connected to a high intensity low power consuming light emitting diode (LED)  20  or a high intensity bulb  12  mounted within a conventional parabolic reflector  14 . Also shown is a focusing shatter proof lens  16  disposed within a rotatable lens ring  18 ,  18 ′ or  18  rotatably secured to housing  24  in front of reflector  14 , having a lens ring gripping surface  19 . The focusing feature is intended to be used with a single primary light source such as an incandescent bulb, but may in the future be usable with one or more LED&#39;s as well. Also seen are two luminescent capsules  22  for making flashlight  10  luminescent and thus conspicuous and easily located in low light conditions. Capsules  22  are secured longitudinally to opposing sides of housing  24 . 
     Housing  24  is formed of translucent, heavy duty, impact resistant plastic with circumferential ribs  24   a  along most of its length to provide a virtually slip-proof gripping surface. Lens ring  18  is internally threaded and the forward end of housing  24  is externally threaded to engagingly and rotatably receive lens ring  18 . Two O-rings  26  are fitted into two O-ring grooves  28  in the exterior of housing  24  adjacent to the housing  24  external threads to create a waterproof seal between housing  24  and lens ring  18 . 
     Capsules  22  are a key inventive feature of the flashlight, and each contains a quantity of tritium  32 . By way of explanation tritium is a radioactive form or radioisotope of the hydrogen atom in which two neutrons are added to the normal single proton in the nucleus of the atom. The half life of this radioisotope is 12.3 years. Tritium is not hazardous outside of living tissue, so therefore it is safe when kept within a specially designed container which, in the case of this invention are capsules  22 . 
     Capsules  22  are each transparent, extremely durable and virtually impenetrable. See FIGS. 2 and 7. Each capsule  22  preferably is formed of two mating capsule halves  34  made of very tough plastic, one of which has a recess  36 . In manufacturing capsules  22 , a small vial V of tritium  32  is placed into a recess  36  of a one of the capsule halves  34 . Each of the capsule halves  34  are equipped with interior faces  38 , which are interrupted with one or more peg(s)  46  and bore(s)  48 . The one or more peg(s)  46  and bore(s)  48  are the preferred method to fixedly attach the capsule halves together. An alternative method is to add a bonding agent  42  in addition or in lieu of the peg(s) and bore(s), which is spread over the interior face  38  surrounding the recess  36  if used. 
     In any event, the vial V of tritium  32  is placed in recess  36  of first capsule half  34  and then a second capsule half  34  is oriented so that first capsule interior face  38  is abutting face to face with the second capsule interior face  38 , and vial V is contained within the recess  36  and then the capsule is assembled. If bonding agent  42  is used, it grips and optionally partially melts the first and second capsule interior faces  38  so that they solidify together. Whether or not bonding agent  42  is used, the assembly of the two capsule halves  34  form a monolithic capsule  22  containing a fully sealed hollow defined by the two opposing capsule halves  34 , one of which includes recess  36 . For all practical purposes, capsule  22  is virtually indestructible. Capsules  22  are each fixedly attached, optionally with agent  42 , longitudinally on opposite sides along the outside surface of housing  24  adjacent to lens ring  18 ,  18  or  18 . It is preferred that a pair of peg portions  46  protrude from one of the capsule half interior face  38  of one of the capsule halves  34  and penetrate into a pair of mating peg bores  48  disposed in the other of the capsule halves  34  for fixedly attaching the capsule halves  34  together. 
     It is preferred that elongate loops  40  or  40 ′, formed of housing material, extend from opposing sides of housing  24  and define a region within loops  40  or  40 ′ which receive and fixedly retain the capsules  22 . Loops  40  or  40 ′ protrude sufficiently from housing  24  that they abut the surface on which flashlight  10  rests when housing  24  rolls, to stop the rolling of housing  24  with the opposing loop  40  and its capsule  22  elevated over the remainder of housing  24  for the user to have an unobstructed view of the elevated capsule  22  so that it can be more readily seen in the dark. 
     Power circuit  30  includes several batteries  44  and a battery coil spring  50 , which biases batteries  44  forwardly within housing  24 . A conductive metal strip  52  is electrically connected to spring  50  and extends along and is embedded longitudinally within a side of housing  24  to deliver electrical power from batteries  44  to LED  20  or to a bulb socket  54 . See FIG.  6 . Rotating the lens ring  18 ,  18 ′ or  18  to tighten it over housing  24  advances the light source toward batteries  44  so that the terminal ends of batteries  44  make firm conductive contact with circuit  30  and thus complete circuit  30  to turn on the flashlight in the manner of a switch. 
     The preferred LED  20  is what is known as a high output, high intensity or ultra bright LED which operates on 4 four volts of electric power. To create sufficient voltage to illuminate such an LED  20 , three C or AA batteries are required, and housing  24  has to be about eight inches long to contain these batteries stacked in series. A larger diameter housing  24  is provided of a conventional, sufficient diameter to receive C batteries. See FIG.  2 . An alternative smaller diameter housing  24  is provided of sufficient diameter to receive AA batteries. See FIGS. 4-5. 
     The larger diameter housing flashlight shown in FIG. 2 may be converted to accept the smaller diameter AA batteries, and at the same time to become buoyant. To achieve this transformation, lens ring  18  and reflector  14  are momentarily removed from housing  24  and a square battery tube  60  is fitted longitudinally into housing  24 . See FIGS. 8 and 9. Battery tube  60  is preferably concentric and coaxial with housing  24  and thus defines an annular floatation air space  62  between battery tube  60  and housing  24 . Battery tube  60  is sized in internal dimension and length to retain three of the AA size batteries, which have a smaller diameter than C size batteries. Floatation air space  62  gives the flashlight buoyancy so that flashlight floats if dropped in the water. Since the batteries  44  are heavy relative to the remainder of the flashlight and since their center of gravity is offset toward the rear of housing  24 , the flashlight floats with the forward end oriented upwardly. As a result, so that capsules  22  with their radiated light are at the water surface, rendering the flashlight visible. Should the LED  20  or bulb  12  in the flashlight be on, its beam of light also makes the flashlight highly visible while floating in this upright orientation. Battery tube  60  has a square cross-section and its external corners loosely abut the interior of housing  24  to generally center tube  60  within housing  24 . 
     The lens ring  18 ,  18 ′ or  18  preferably contains a tab of catalyst material  64  secured along the ring inward surface for absorbing or neutralizing any hydrogen gas emitted by the batteries  44 . Catalyst  64  thereby prevents a build-up of hydrogen gas within housing  24 , which might be detonated by electricity within circuit  30  and cause injury to the user. One or several LED&#39;s  20  may be attached through LED ports in a disk-shaped mounting plate  72 . See FIG.  2 . LED&#39;s  20  are spaced inwardly from the sides of plate  72  to be centered to cast more light out of housing  24 , and so a spacer ring  74  is preferably fitted around LED&#39;s  20  to fill the gap between the LED&#39;s and the outside diameter of housing  24 . Catalyst  64  is preferably attached to the inward surface of spacer ring  74 . 
     Second Preferred Embodiment 
     A compact flashlight is provided with a shorter housing  24  containing only one battery  44 . See FIGS. 1-3, generally. One battery cannot create sufficient voltage to operate a high intensity LEp  20 , and so an high intensity bulb  12  is substituted for LED  20 . The preferred high intensity bulb  12  is what is known as a “Xenon” bulb. 
     While the invention has been described, disclosed, illustrated and shown in various terms with a preferred embodiment where it clear that other embodiments or modifications may be assumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims appended hereto.