This invention relates generally to flashlights, such as flashlights adapted to be worn on the heads of individuals as personal headlamps. Such headlamps are worn to provide illumination in a wide variety of applications, including camping, hiking, cave exploration, diving, and the like. The invention relates more particularly to a device adapted for use as an auxiliary flashlight, which may be attached to the headstrap of a primary personal headlamp, or to another strap, such as a belt, the strap of a backpack, or the like.
Typical personal headlamps are shown in U.S. Design Pat. D405202 dated Feb. 2, 1999, and D470615, dated Feb. 18, 2003. In most cases, the headlamp is supported on the wearer's head by a headstrap, in the form of a band of flexible material, usually a stretchable fabric, adapted to fit about an individual's head so that the headlamp is supported on the forehead. The headstrap extends through slots in a bracket attached to an assembly comprising one or more incandescent bulbs or light-emitting diodes, a reflector, a switch, and associated electrical wiring or control circuitry. The assembly may include a power source compartment for containing one or more electrochemical cells (“batteries”). However, in the case of higher power headlamps, the power source compartment is often a separate unit at a location remote from the light-emitting device or devices.
One of the problems encountered by users of personal headlamps is that drainage of the power source can result in inopportune loss of illumination. Moreover, it is usually difficult to replace the batteries, especially in the dark, and when the power source compartment is closed by screw fasteners or the like, so that a tool is required to open it. Failure of the headlamp can also occur due to filament burn-out in the case of an incandescent bulb, and for various other reasons such as mechanical failure of a switch, or corrosion due to moisture. There is a need, therefore, for a suitable auxiliary illumination device to serve as a back-up source of illumination in the event of failure of the primary headlamp.
Carrying a second headlamp or flashlight as a spare is generally not a practical solution, especially in hiking and other activities where pack weight minimization is important. Moreover, providing two headlamps on a single headstrap is unwieldy, and requires the user to carry significant additional weight.
Objects of this invention, therefore, are to provide an auxiliary device that can be used as a back-up source of illumination in the event of failure of a primary headlamp or other portable source of illumination, to provide for quick and convenient operation of the auxiliary device in the event of an emergency, and to minimize the added weight that the user must carry. It is also an object of the invention to provide an auxiliary illumination device the aim of which can be adjusted easily, and to provide an illumination device that can be quickly and easily detached from a strap, such as the headband of a personal headlamp, so that it can be used as a hand-held flashlight, but which is normally held securely in place on the strap.
In accordance with the invention, a flashlight for attachment to a strap, comprises a lamp body, and a strap bracket having a strap-receiving slot through which a strap can extend with a portion of the strap held in the slot. The lamp body is removably attachable to the strap bracket, and, when the portion of the strap is held in the strap-receiving slot, and the lamp body is attached to the strap bracket, the lamp body is rotatable about an axis of rotation which extends in perpendicular relationship to the portion of the strap held in the slot, and the lamp is arranged to project a beam of light in substantially perpendicular relationship to the axis about which the lamp body is rotatable.
In the preferred embodiment, the lamp body has inner and outer walls facing in opposite directions, and the light source is mounted on the lamp body and arranged to project light in a direction transverse to the directions in which the inner and outer walls face. At least two retaining projections are fixed to the inner wall of the lamp body. Each retaining projection is spaced radially from a common axis extending along said opposite directions. Each projection has a leg extending in the direction in which the inner wall faces, and a foot spaced from the inner wall and extending from the leg radially with respect to the common axis. The strap bracket a slotted face having, for each retaining projection, a corresponding arcuate slot centered on the common axis. The leg of each of the retaining projections extends through a corresponding arcuate slot and is slidable therein as said lamp body is rotated about the common axis. Each slot has an undercut cross-section accommodating the radially extending foot of its corresponding retaining projection, and each arcuate slot is sufficiently narrow to prevent the foot of its corresponding retaining projection from passing outwardly therethrough. The slots have open ends positioned so that the legs of the retaining projections can pass therethrough substantially simultaneously for detachment of the lamp body from the strap bracket.
Preferably, cooperating detent elements are provided on the lamp body and the strap bracket. These cooperating elements are engageable in each of a plurality of rotational positions of the lamp body about the common axis, for retaining the lamp body in any selected one of the plurality of rotational positions. The detent elements on the lamp body and the strap bracket are preferably resiliently engageable, so that the retention of the lamp body in each of the rotational positions can be overcome by manual application of a predetermined twisting force to the lamp body.
The strap-receiving slot preferably has parallel upper and lower boundaries for engagement with the opposite edges of a strap extending through it, and the light source is adapted to project a beam of light in a pattern substantially symmetrical about a central axis transverse to the directions in which the inner and outer walls of the lamp body face. The retaining projections are positioned so that they are adjacent the openings of their corresponding arcuate slots, but outside the slots, for attachment and detachment of the lamp body to and from the strap bracket, when the lamp body is tilted so that the central axis of the beam of light projected by the light source is tilted relative to the parallel upper and lower boundaries of the strap-receiving slot.
Preferably, the arcuate slots extend about the common axis through ranges such that, by rotation of the lamp body about the common axis, the central axis of the beam of light can be aimed both above and below a direction parallel to the parallel upper and lower boundaries of the strap-receiving slot.
The outer wall of the lamp body is preferably constituted in part by a manually actuable operating button for switching electrical power to the light source, and an electrical power source is preferably located within the lamp body.
In a preferred embodiment, the flashlight is used as an auxiliary headlamp, for attachment to the headstrap of a personal headlamp.
Other objects, details and advantages of the invention will be apparent from the following detailed description when read in conjunction with the drawings.
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The upper and lower boundaries 26 and 28 of the slot 14 should be parallel to each other, and spaced from each other by a distance approximately equal to the width of the strap, so that the bracket will not tilt on the strap. Barbs, e.g., barb 30, may be formed on the tips of the hook-shaped elements to ensure secure attachment of the bracket 12 to the strap. A semicylindrical groove 32 is preferably formed in a wall of the strap bracket to receive a cable 34 (
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The projections 62 and 64 are positioned relative to each other, and to the open ends of slots 44 and 46, so that, when projection 60 enters hole 48, the projections can move, in the direction of axis 54, to positions such that, upon rotation of the lamp body, their legs can enter the slots.
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The feet of the projections 62 and 64 are cooperatively engageable with detents formed as protuberances on the front face of strap-receiving body 43, as shown in
As will be apparent from the above description and the drawings, the strap bracket of the auxiliary flashlight can be secured to a headstrap of a headlamp, or to any similar strap, and the lamp body can be secured to the strap bracket by positioning its projections 62 and 64 so that the legs are located adjacent the open ends of slots 44 and 46, respectively, and then rotating the lamp body so that the legs of the projections enter the slots and the feet of the projections are situated within the recessed area behind the slotted plate 45. Lamp body can be held at any one of several selected positions by the cooperation of the feet of projections 62 and 64 with the detents in detent series 72 and 70.
The lamp body can be readily attached to, and detached from, the strap and operated either while attached to the strap, or while separated from the strap. While attached to the strap, the auxiliary lamp can be adjusted to, and held in, any of several positions, in order to direct the light emitted by light source 42 either horizontally, or at any of several discrete angles above and below horizontal.
Various modifications in addition to those specifically mentioned above can be made to the auxiliary flashlight in accordance with the invention. For example, lamp body can be formed in any of a variety of shapes; the feet need not be aligned with the light source; and the strap bracket can be constructed without opening 24 (