LED flashlight with heat-dissipating plate

A flashlight includes a battery housing, a lamp seat, a lamp unit, a heat-conductive casing, and a heat-dissipating plate. The lamp seat is mounted on one end of the battery housing. The lamp unit includes a substrate having a first side provided with a metal layer, and an LED lamp mounted on a second side of the substrate opposite to the metal layer. The heat-conductive casing is attached to the battery housing, and is disposed around the lamp seat and the lamp unit. The heat-dissipating plate is sandwiched between the lamp seat and the metal layer of the substrate, and is in contact with the heat-conductive casing. Heat generated by the lamp unit is dissipated via the metal layer, the heat-dissipating plate, and the heat-conductive casing.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of Taiwanese Application No. 094143588, filed on Dec. 9, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a flashlight, more particularly to a flashlight with a heat-dissipating mechanism for fast heat-dissipation.

2. Description of the Related Art

In Taiwanese utility model no. M244398, entitled “High-illumination LED Flashlight”, the applicant discloses a high-illumination light-emitting diode (LED) flashlight, where the power of an LED lamp thereof is approximately equal to 1 watt. The LED lamps used in flashlights prior to the high-illumination LED flashlight only produce power that ranges from 0.1 to 0.2 watts. Therefore, the high-illumination LED flashlight illuminates with higher intensity and brightness. However, since small batteries can only provide limited continuous electric power, the high-illumination LED flashlight developed by the applicant is restricted to small-sized applications, and cannot produce power of higher than 1 watt. Structures of the high-illumination LED flashlight that surround the LED lamp are easily damaged and melt due to intense heat generated by the LED lamp. Consequently, manufacturers are striving to provide an efficient heat-dissipating mechanism for flashlights, whether small-sized or large-sized, with high power and high illumination.

SUMMARY OF THE INVENTION

Therefore, the object of the present invention is to provide a flashlight with a heat-dissipating mechanism that is capable of dissipating heat generated by a lamp unit thereof out of a housing.

According to the present invention, there is provided a flashlight that includes a battery housing, a lamp seat, a lamp unit, a heat-conductive casing, and a heat-dissipating plate. The lamp seat is mounted on one end of the battery housing. The lamp unit includes a substrate having a first side provided with a metal layer, and an LED lamp mounted on a second side of the substrate opposite to the metal layer. The heat-conductive casing is attached to said one end of the battery housing, and is disposed around the lamp seat and the lamp unit. The heat-dissipating plate is sandwiched between the lamp seat and the metal layer of the substrate, and is in contact with the heat-conductive casing. Heat generated by the lamp unit is dissipated via the metal layer, the heat-dissipating plate, and the heat-conductive casing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before the present invention is described in greater detail, it should be noted herein that like elements are denoted by the same reference numerals throughout the disclosure.

As shown inFIG. 1,FIG. 2, andFIG. 3, the first preferred embodiment of a flashlight according to the present invention includes a battery housing21, a lamp seat23, a lamp unit25, a heat-dissipating plate26, a heat-conductive casing27, a reflector29, and a protective cover28.

The battery housing21is an elongated tube that is made of a metal material, and has an open end210and a closed end211that are opposite to each other. A housing wall of the battery housing21that is proximate to the open end210has an outer wall face formed with an external screw thread218, and an inner wall face formed with an inner shoulder219(shown inFIG. 2andFIG. 3). The battery housing21is formed with a battery-receiving compartment212that extends from the open end210to the closed end211, and that is adapted to receive at least one battery therein. The open end210permits insertion of the battery into the battery-receiving compartment212. The battery housing21includes a first elastic member213that is made of a metal material, and that is disposed in the battery-receiving compartment212proximate to the closed end211. In this embodiment, two batteries215are disposed in the battery-receiving compartment212such that a negative electrode216of one of the batteries215contacts the first elastic member213, thereby establishing an electrical connection among the first elastic member213, the battery housing21, and the negative electrodes216of the batteries215. In other words, the first elastic member213and the battery housing21are both negatively charged.

The lamp seat23is mounted on the open end210of the battery housing21, and abuts against the inner shoulder219of the inner wall face of the housing wall. The lamp seat23includes a support base230, a lamp seat inner tubular wall233, and a lamp seat outer tubular wall234. The support base230has a first surface231that is in contact with the heat-dissipating plate26, and is formed with a lamp seat central hole232. The lamp seat inner tubular wall233extends from the lamp seat central hole232in a direction away from the heat-dissipating plate26. The lamp seat outer tubular wall234extends laterally from the support base230around the lamp seat inner tubular wall232. In this embodiment, the lamp seat23further includes a second elastic member235that is made of a metal material, and that is disposed in the lamp seat central hole232. The second elastic member235has a length such that when the second elastic member235is received in the lamp seat central hole232, two ends thereof extend outwardly of the support base230. The end of the second elastic member235contacts a positive electrode217of the other one of the batteries215. In other words, the second elastic member235is positively charged.

Moreover, the lamp seat23is provided with a first groove236that extends axially in the lamp seat outer tubular wall234, and a second groove237that extends radially in the support base230and that is connected to the lamp seat central hole232.

Further, the lamp seat23is provided with a first annular groove2301that extends annularly in the lamp seat outer tubular wall234, and that is disposed proximate to the first surface231of the support base230. The first surface231is provided with a pair of symmetrical securing teeth2311.

The lamp unit25includes a substrate250and an LED lamp251. The substrate250is substantially polygon-shaped, and has a metal layer257at a first side thereof. The LED lamp251is mounted on a second side258of the substrate250opposite to the metal layer25. In this embodiment, the substrate250is substantially hexagonal, and further has an outer periphery formed with a plurality of angularly spaced apart notches252. Each of the notches252is disposed between two adjacent sides of the hexagonal substrate250. In other words, the substrate250has six notches252. The substrate250includes first and second electrodes253,254that are connected to two leads of the LED lamp251, respectively. The metal layer257of the substrate250aids in dissipating heat generated by the LED lamp251.

The heat-dissipating plate26is sandwiched between the first surface231of the support base230of the lamp seat23and the metal layer257of the substrate250of the lamp unit25, and is in contact with the heat-conductive casing27. In particular, the heat-dissipating plate26includes a central part260, and a plurality of fins261extending outwardly and radially from the central part260to contact an inner surface271of the heat-conductive casing27. The number of fins261is chosen to be equal to the number of sides of the substrate250. The fins261project outward from the sides of the substrate250, respectively.

The lamp seat23further includes a first conductor238that extends into the first groove236, and a second conductor239that extends into the second groove237. In this embodiment, the first and second conductors238,239are in the form of bent rods. The first conductor238has a portion2381in contact with an inner surface214of the battery housing21such that the first conductor238is in electrical connection with the battery housing21. The second conductor239has a portion2391that extends into the lamp seat central hole232and that contacts the second elastic member235, which in turn is connected to the positive electrode217of the batteries215, and another portion2392that extends radially in the second groove237.

When the lamp seat23, the substrate250, and the heat-dissipating plate26are assembled, the first and second electrodes253,254of the substrate250are aligned respectively with the first and second grooves236,237. The securing teeth2311of the first surface231respectively engage two of the notches252in the substrate250. Subsequently, the first and second electrodes253,254are respectively soldered to another portion2382of the first conductor238and the portion2392of the second conductor239, thereby connecting the first electrode253electrically to the first conductor238, the battery housing21, the first elastic member213, and the negative electrodes216of the batteries215, while connecting the second electrode254electrically to the second conductor239, the second elastic member235, and the positive electrodes217of the batteries215. Consequently, the LED lamp251can be activated when a closed circuit is made.

In this embodiment, the heat-dissipating plate26further includes at least two anchoring fingers262, each of which extends radially and outwardly from the central part260between two adjacent ones of the fins261. Each of the anchoring fingers262is folded backward and extends to the second side258of the substrate250through one of the notches252.

The heat-conductive casing27is attached to the open end210of the battery housing21, and is disposed around the lamp seat23, the heat-dissipating plate26and the lamp unit25. The heat-conductive casing27is sleeved around the open end210of the battery housing21, and engages threadedly the external screw thread218. The lamp seat outer tubular wall234is inserted into the open end210of the battery housing21. The heat generated by the LED lamp251is dissipated via the metal layer257of the lamp unit25, the heat-dissipating plate26, the heat-conductive casing27, and the battery housing21.

The reflector29is disposed adjacent to the second side258of the substrate250of the lamp unit25, and is formed with a through hole291for extension of the LED lamp251therethrough, and a second annular groove293.

The protective cover28has a cover wall280disposed inside the heat-conductive casing27. The cover wall280surrounds the lamp seat23, the lamp unit25and the heat-dissipating plate26. The fins261of the heat-dissipating plate26penetrate the cover wall280, and have bent end parts264(as shown inFIG. 2andFIG. 3) that extend axially and outwardly of the cover wall280and that are sandwiched between the cover wall280and the heat-conductive casing27.

In this embodiment, the protective cover28has two cover components281,282that cooperate with each other to form the cover wall280. The cover components281,282have semicircular cross-sections such that the cover wall280has a circular cross-section. Each of the cover components281,282is provided with first and second ridges285,286disposed proximate to the lamp seat23and the reflector29, respectively, and apertures283for outward extension of the bent end parts264of the fins261of the heat-dissipating plate26. When the cover components281,282are assembled to form the cover wall280, the first ridges285engage the first annular groove2301of the support base230of the lamp seat23, the second ridges286engage the second annular groove293of the reflector29, and the apertures283have the bent end parts264of the fins261extending outwardly thereof.

The flashlight further includes a lens301, a protective shield302, and a reflector housing303, which are assembled with the heat-conductive casing27. The heat-conductive casing27surrounds the cover wall280of the protective cover28, and abuts against the bent end parts264of the fins261. The lens301and the protective shield302are movable with the reflector housing303. The threaded engagement between the reflector housing303and the heat-conductive casing27permits adjustments to the distance between the lens301and the LED lamp251, i.e., focusing adjustments.

With the present invention, the heat generated by the LED lamp251can be rapidly dissipated via the metal layer257of the lamp unit25, the heat-dissipating plate26, the heat-conductive casing27, and the battery housing21, thereby protecting components of the flashlight from damage due to the heat generated even when the power of the LED lamp251is chosen to exceed 1 watt.

As shown inFIG.4, the second preferred embodiment of a flashlight according to the present invention differs from the first preferred embodiment only in the lamp seat23′ and the lamp unit25′.

Instead of the second elastic member235employed in the first preferred embodiment, the lamp seat23′ includes a conductive insert235′ having an insert tubular wall2351′ inserted into the lamp seat inner tubular wall233(as shown inFIG. 3) and an end plate2352′ in contact with the positive electrode217of one of the batteries215. In addition, the lamp seat23′ further includes a conductive cap33sleeved onto the lamp seat outer tubular wall234and contacting an inner surface of the battery housing21. The first conductor238′ is connected electrically to the end plate2352′ of the conductive insert235′ and the first electrode253′ of the substrate250′ of the lamp unit25′. The second conductor239′ is connected electrically to the conductive cap33and the second electrode254′ of the substrate250′. The lamp seat23′ according to the second preferred embodiment is capable of achieving the same effects and advantages as the first preferred embodiment.