Modular flashlight and method of use therefor

A flashlight includes a flashlight head assembly that may be used with either one or two batteries. For use with one battery, a body receives a battery therein and the flashlight head assembly is secured to the body. For use with two batteries, an extension unit is secured to the body and the flashlight head assembly is secured to the extension unit. A switch assembly disposed in the body and electrically connected with the flashlight head assembly controls the delivery of power to the flashlight head assembly.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a flashlight and, more particularly, but not by way of limitation, to a modular flashlight and a method of use therefor.

2. Description of the Related Art

Different situations create scenarios where a variety of flashlight alternatives are necessary. For example, outdoor use may require a bright flashlight with a long burn time. Under such a scenario, flashlight size may not be important, which is preferable, as brighter flashlights with longer burn times tend to be larger in size. Nevertheless, there are other scenarios where ease of carry through the use of a smaller less bright flashlight is most important. Consequently, there are a wide variety of flashlights available, each designed to satisfy a different scenario. Unfortunately, this necessitates the purchase as well as the transport of many different flashlights. Accordingly, a flashlight that is bright, provides suitable burn time, and is modular to satisfy different scenarios would be desirable.

SUMMARY OF THE INVENTION

In accordance with the present invention, a flashlight is modular in that the flashlight includes a flashlight head assembly adapted to operate with either one battery or two batteries. In the one battery configuration, the flashlight head assembly connects with a body adapted to receive a battery therein. Activation of a switch assembly disposed in the body delivers power from the battery to the flashlight head assembly. In the two battery configuration, an extension unit adapted to receive a battery therein connects to the body and the flashlight head assembly connects to the extension unit. Activation of the switch assembly delivers power from the two batteries to the flashlight head assembly.

The flashlight head assembly includes an LED driver circuit that drives an LED of the flashlight head assembly. The LED driver circuit includes a voltage buck/boost that provides regulated voltage from the one battery or two batteries to an LED driver. The LED driver circuit further includes a voltage reference circuit that monitors incoming voltage to the buck/boost and prevents damage to the LED driver circuit by limiting the incoming voltage to a preset value. The LED driver circuit still further includes a current monitor/regulator that maintains a constant current in the LED independent of the voltage applied to the buck/boost.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1illustrates a flashlight10in a first configuration that utilizes a single battery as a power source. The flashlight10in the first configuration includes a body11, a switch assembly12disposed in the body11, and a flashlight head assembly13coupled with the body11.FIG. 2illustrates the flashlight10in a second configuration that utilizes two batteries as a power source. The flashlight10in the second configuration includes the body11, the switch assembly12disposed in the body11, an extension unit14coupled with the body11, and the flashlight head assembly13coupled with the extension unit14.

Referring toFIGS. 3 and 4, the body11includes a bore16that begins at a first open end17of the body11and ends at a second closed end18of the body11. The bore16provides the body11with a battery compartment19and a switch assembly compartment20. The battery compartment19is adapted to receive one battery. The first end17of the body11includes threads23that facilitate securing of the flashlight head assembly13onto the body11in a position aligned with the axis of the body11. Alternatively, the threads23that facilitate securing of the extension unit14onto the body11in a position aligned with the axis of the body11. The first end17of the body11further includes a groove92that receives an o-ring93therein. The o-ring93provides a fluid tight seal between the body11and the flashlight head assembly13or the extension unit14. The body11further includes a base21and a switch aperture24at the base21. The base21provides a planar surface on the body11for the switch assembly12.

A hitch ball furnishes the flashlight10with a striking implement at the second end18of the body11, which, illustratively, may be employed to break an automobile window during an emergency situation. The second end18includes a threaded aperture26that receives the hitch ball therein. The hitch ball includes a threaded bolt portion that engages the threaded aperture26to secure the hitch ball to the body. The hitch ball includes an aperture therethrough that permits attachment of a lanyard to the flashlight10.

While the threaded aperture26primarily functions to facilitate securing of the hitch ball to the flashlight10, those of ordinary skill in the art will recognize that other suitable objects may be secured to the flashlight10. Illustratively, a baton may be secured to the flashlight10. The baton includes a threaded bolt portion that engages the threaded aperture26to secure the baton to the body11, thereby providing the flashlight10with a self-defense baton feature. The baton may include a threaded aperture that is engaged by the threaded bolt portion of the hitch ball to permit the securing of the hitch ball to the baton. Still further, a firearm, such as a shotgun, including a threaded bolt portion would permit the securing of the flashlight10thereto.

The switch assembly12includes a switch cap51, a switch housing52, and a switch53. The switch cap51includes a convex shape and is constructed from any suitable water resistant rubberized or plasticized material using well-known manufacturing techniques, such as vacuum forming or injection molding. The switch53is a push-button type switch of well-known design and is available from Switch Channel, P.O. Box 31557, Los Angeles, Calif. 90031.

The switch housing52is cylindrical in shape and has a diameter that permits frictional engagement with the inner walls of the switch assembly compartment20. The switch housing52provides a support platform for the switch53and is constructed from any suitable water resistant plastics material using well-known manufacturing techniques, such as machining or injection molding. The switch housing52includes a cavity54, contact apertures55and56, and a groove57that receives therein an o-ring58. The switch53seats within the cavity54of the switch housing52and is held in place using any suitable means such as a rod inserted into the switch housing that abuts the switch, friction, or an adhesive. A terminal59fits through the contact aperture55and electrically connects via a conductive disc or soldering to a ground contact of the switch53, thereby forming a ground terminal63for the switch assembly12. Similarly, a terminal60fits through the contact aperture56and electrically connects via a conductive disc or soldering to a positive contact of the switch53, thereby forming a positive terminal64for the switch assembly12.

Once the switch53has been seated within and electrically connected to the switch housing52, the switch housing52inserts into the switch assembly compartment20through the first open end17of the body11. The switch housing52inserts into the switch assembly compartment20until the switch housing52abuts the second closed end18of the body11. The abutment of the switch housing52with the second closed end18of the body11and the o-ring58provide a fluid tight seal at the second end18of the flashlight10. Further, when the switch housing52abuts the second closed end18of the body11, the switch housing52locates the switch53such that the switch53protrudes through the switch aperture24to permit activation of the switch53by a user of the flashlight10. With the switch housing52properly located within the switch assembly compartment20and the switch53protruding through the switch aperture24, the switch cap51fits over the switch53and the switch aperture24and is frictionally held in place by a lip67of the switch aperture24in order to provide the switch assembly with a fluid tight seal. In addition, the positive terminal64protrudes into the battery compartment19to engage battery65, and the ground terminal63engages the switch assembly compartment20to complete a circuit that powers the flashlight head assembly13upon the activation of the switch53by a user.

The switch assembly12is located at the cylindrical portion of the body11adjacent the second closed end18of the body11but not on the second closed end of the body11in order to permit grasping of the flashlight10with either an overhand grip as used by law enforcement or an underhand grip. In particular, the switch assembly12may be accessed by the thumb of a user from either an overhand grip or an underhand grip without the necessity of changing the position of the thumb relative to the switch assembly12. Moreover, the base21on the cylindrical portion of the body11seats the thumb over the switch assembly12. The location of the switch assembly12on the cylindrical portion of the body11accordingly improves over flashlights with switches located at the rear thereof, near the head thereof, or on the head thereof because such switch locations do not permit ease of use with both an overhand grip as used by law enforcement and an underhand grip.

Referring toFIGS. 5-13, a flashlight head assembly13is adapted for use with the flashlight10and includes a flashlight head270, a lens271, a reflector272, a heat sink273, and an LED assembly274. The flashlight head270includes a bore275therethrough beginning at a first end276and ending at a second end277. The flashlight head270at the first end276includes a lip278that provides a surface for retaining the lens271within the flashlight head270. The flashlight head270at the second end277includes threads279internal thereto that maintain the heat sink273within the flashlight head270as well as facilitate the securing of the flashlight head assembly13onto the body11or the extension unit14.

The LED assembly274includes a printed circuit board285, an insulator326, an LED284electrically coupled with the printed circuit board285via an input post286and a return post295electrically connected to the printed circuit board285, and micro-electronic circuitry294mounted onto the printed circuit board285such that the micro-electronic circuitry294and the printed circuit board285form an LED driver circuit250. The micro-electronic circuitry294is electrically coupled with the LED284through the printed circuit board285to control the delivery of power to the LED284. The LED assembly274further includes a positive input terminal296connected with the printed circuit board285at a central portion thereof. The positive input terminal296is electrically coupled with the micro-electronic circuitry294via the printed circuit board285. The LED assembly274still further includes a ground terminal297connected with the printed circuit board285at an edge thereof. The ground terminal297resides in a slot325of the heat sink273and is electrically coupled with the micro-electronic circuitry294via the printed circuit board285.

The current level necessary to operate the LED284is predetermined and the same for the first configuration and the second configuration of the flashlight10. Consequently, the LED driver circuit250may be the same for the first configuration and the second configuration of the flashlight10because the micro-electronic circuitry294delivers the current level necessary to operate the LED284regardless of whether there is one battery as per the first configuration applying a first voltage and operating the LED284at a first output level or two batteries as per the second configuration applying a second voltage and operating the LED284at a second output level. The micro-electronic circuitry294as perFIG. 13includes a voltage buck/boost310, an LED driver311, a voltage reference circuit312, and a current monitor/regulator313. The voltage buck/boost310modulates the voltage delivered from the battery or batteries to ensure the voltage applied to the LED284by the LED driver311is sufficient to operate the LED284. The LED driver drives the LED284, and, in this preferred embodiment, the LED driver is any suitable transistor such as a MOSFET. The voltage reference circuit312monitors the incoming voltage to the buck/boost310to ensure the incoming voltage does not exceed a high threshold established for the delivery of voltage to the buck/boost310. The current monitor/regulator313controls the LED driver311such that the LED driver311delivers a constant current to the LED284independent of the voltage applied by the buck/boost310.

The heat sink273, which is constructed from any suitable conductive material, such as aluminum, secures the LED assembly274within the flashlight head270and further delivers heat generated by the LED assembly274to the flashlight head270and the body11. The heat sink273includes threads289on an exterior portion thereof that engage the threads279of the flashlight head270to secure the heat sink273within the flashlight head270. The heat sink273includes a slot288that may be engaged by a tool such as needle nose pliers to insert the heat sink273into the flashlight head270. A first cavity280at a first end282of the heat sink273provides a space for the mounting of the LED284to the heat sink273. Within the first cavity280, the heat sink273includes a raised portion328that seats the LED284. The inclusion of the raised portion328within the first cavity280creates a groove327that receives the insulator326therein. Similarly, a second cavity300at a second end283of the heat sink273provides a space for the mounting of the printed circuit board285within the heat sink273. A first aperture298and a second aperture299pass from the first cavity280to the second cavity300to permit a respective one of the input post286and the return post295of the LED284to extend into the second cavity300. The heat sink273is countersunk at the second end283thereby creating a detent301that seats the printed circuit board285within the heat sink273.

The LED assembly274is built into the heat sink273, which enhances the ability of the heat sink273to dissipate heat generated by the LED assembly274. In particular, once the LED driver circuit250is constructed, including the electrical connection of the input post286, the return post295, the positive input terminal296, and the ground terminal297to the printed circuit board285, the printed circuit board285with the micro-electronic circuitry294facing the second cavity300is inserted into the second cavity300until the edge on the printed circuit board285abuts the detent301. In addition, and upon insertion of the printed circuit board285into the second cavity300, the input post286passes through the first aperture298and the return post295passes through the second aperture299such that the input post286and the return post295extend into the first cavity280. The insulator326is placed within the groove327to insulate the LED284from the heat sink273. Moreover, the insulator326includes a first aperture that receives the input post286therethrough and a second aperture that receives the return post295therethrough such that the insulator326aligns the input post286and the return post295within the first cavity280. A heat sink grease, which thermally connects the LED284to the heat sink273, is applied to the raised portion328within the first cavity280followed by the placement of the LED284onto the raised portion328. The LED284fits within the first cavity280and resides atop the raised portion328such that only the lens portion of the LED284extends above the first end282of the heat sink274. After placement of the LED284within the first cavity280, the anode terminal of the LED284is electrically connected with the input post286and the cathode terminal of the LED284is electrically connected with the return post295, thereby securing the LED assembly274within the heat sink273.

Construction of the flashlight head assembly13begins with the insertion of an o-ring290into the flashlight head270until the o-ring290abuts the lip278of the flashlight head270. The lens271inserts into the flashlight head270until the lens271abuts the o-ring290. An o-ring291then inserts into the flashlight head270until the o-ring291abuts the lens271. After insertion of the o-ring291, the reflector272inserts into the flashlight head270until the reflector272abuts the o-ring291. The O-rings290and291create a fluid tight seal at the first end276of the flashlight head270and further protect from damage the edges of both the lens271and the reflector272. The heat sink273, which includes the LED assembly274built therein as previously described, screws within the flashlight housing270until the first end282of the heat sink273abuts the reflector272. In that position, the lens of the LED284protrudes into the reflector272, which directs the light produced from the LED284through the lens271and from the flashlight head270. Once construction of the flashlight head assembly13is completed, the flashlight head assembly13may be secured to the body11to produce the flashlight10according to the first configuration or to the extension unit14to produce the flashlight10according to the second configuration. It should be understood that securing the flashlight head assembly13to the body11or to the extension unit14facilitates abutment of the positive input terminal296with the battery65or battery66and the ground terminal297with the leading edge of the body11or the extension unit, thereby providing an electrical connection between the flashlight head assembly13and the body11or the extension unit14. Consequently, activation of the switch assembly12delivers power to the LED assembly274via a circuit encompassing the battery or the batteries of the flashlight10, the positive input terminal296, the micro-electronic circuitry294, the LED284, the ground terminal297, possibly the extension unit14, the body11, and the switch assembly12.

An advantage in the design of the flashlight head assembly13is that the LED assembly274is built within the heat sink273such that the heat sink273substantially completely surrounds the LED284, the printed circuit board285, and the micro-electronic circuitry294. In particular, substantially completely surrounding the LED assembly274with the heat sink273maximizes surface area contact between the heat sink273and the LED assembly274, thereby enhancing the exchange of heat from the LED assembly274to the heat sink273. Further, substantially completely surrounding the LED assembly274with the heat sink273maximizes the mass of conductive material about the LED assembly274, thereby enhancing the exchange of heat from the LED assembly274to the heat sink273. A further advantage in the design of the flashlight head assembly13A is that the heat sink273contacts the flashlight head270, which essentially transforms the entire flashlight head assembly13into a heat sink for the LED assembly274. Consequently, when the flashlight head assembly13is secured to the body11, the body11acts as a heat sink to further enhance the dissipation of heat generated by the LED assembly274.

The reflector272may be constructed of a plastics material with a reflective coating that directs the light produced from the LED284through the lens271and from the flashlight head270. The reflector272in the third embodiment is cylindrically shaped, which enhances the strength thereof. Cost considerations may be the driving factor in selecting a reflector constructed from a plastics material. Alternatively, the reflector272may be constructed from any suitable conductive material, such as aluminum, which is polished to provide a reflective surface that directs the light produced from the LED284through the lens271and from the flashlight head270. The reflector272may be constructed from conductive material when it is desired to enhance the dissipation of heat generated by the LED assembly274. Particularly, a reflector272constructed from conductive material abuts the printed circuit board285of the LED assembly274, thereby rejecting heat generated on the printed circuit board285by the micro-electronic circuitry294. The contact of a reflector272constructed from conductive material with the printed circuit board285of the LED assembly274effectively adds an additional heat sink, thereby increasing the rejection of heat generated by the LED assembly274. Moreover, the reflector272is cylindrically shaped, which enhances the strength of thereof as well as increases the surface area available for the rejection of heat.

The flashlight10in the first configuration with the flashlight head assembly13secured to the body11provides a user with a compact flashlight that is easily carried. The flashlight10in the first configuration includes one battery and provides a user with a bright light and adequate burn time for most situations.

In a situation where a user desires a brighter light and a longer burn time, the user simply removes the flashlight head assembly13from the body11, secures the extension unit14to the body11, places a second battery within the extension unit14, and secures the flashlight head assembly13to the extension unit14. The extension unit14as shown inFIGS. 3 and 4includes a first end317, a second end318, and a bore316therethrough. The extension unit14is sized such that a battery may be placed therein, which provides the flashlight10with a second battery and forms the second configuration of the flashlight10. The second end318includes threads324therein that facilitate the securing of the extension unit14to the body11in a position aligned with the axis of the body11. The first end317includes threads323that facilitate the securing of the flashlight head assembly13to the extension unit14in a position aligned with the axis of the body11. The first end317of the body11further includes a groove319that receives an o-ring320therein. The o-ring provides a fluid tight seal between the extension unit14and the flashlight head assembly13.

While the flashlight10has been described with two configurations employing either one or two batteries, those of ordinary skill in the art should recognize that, in light of the foregoing disclosure, other configurations may include additional batteries creating a flashlight10with a flashlight head assembly13operable with three or more batteries. Moreover, although the present invention has been described in terms of the foregoing embodiment, such description has been for exemplary purposes only and, as will be apparent to those of ordinary skill in the art, many alternatives, equivalents, and variations of varying degrees will fall within the scope of the present invention. That scope, accordingly, is not to be limited in any respect by the foregoing description; rather, it is defined only by the claims that follow.