A light-emitting product (for example, a flashlight) includes a first housing includes a light source for emitting light and a lens system that is adjustable in position relative to the light source. The second housing can be attached to the first housing and includes a power source for the light source. When the first housing and the second housing are attached, the first housing and the second housing can be moved relative to each other to adjust the position of the lens system relative to the position of the light source to focus the light from the light source.

TECHNICAL FIELD

This invention relates to light-emitting products such as flashlights.

Flashlights generally include a light source that can be focused in some manner. Historically, some flashlights included a reflector but not a lens. The light beam emitted from these flashlights often could be adjusted by altering the relative position of the reflector and the light source. This has been accomplished using mechanisms that either move the reflector relative to the light source or move the light relative to the reflector. For example, a head assembly including a light source might be screwed onto a flashlight body including the reflector, or vice versa, and turning the head assembly would move the light source and the reflector relative to each other.

Often types of flashlights do not include a reflector but do include a lens system including one or more lenses that can be used for focusing. Focusing in these flashlights involve altering the relative position of the lens system and the light source. This generally has been accomplished by (1) fixing the position of the lens system in the head assembly and moving the lens system relative to a light source fixed in the flashlight body when the head assembly is screwed onto the body, (2) mounting the lens system in a housing that is moved relative to a light source by a mechanism analogous to those found on some video projectors, or (3) using a fixed head assembly including a lens system and a light source that can be moved relative to the lens system by rotating a ring. In a commercial version of the third design the head assembly is not detachable from the flashlight body.

Another known flashlight includes a fixed reflector, a fixed light source, a movable lens system, and a motor that moves the lens system for focus.

SUMMARY

In one aspect, the invention features a light-emitting product, such as a flashlight, that includes a first housing and a second housing that can be attached to the first housing. The first housing includes a lens system fixed in position within the first housing, a reflector also fixed in position within the first housing, and a lens system that is adjustable in position relative to the light source and the reflector. The second housing includes a power source, such as a battery, for the light source. When the first housing and the second housing are attached they can be moved relative to each other to adjust the position of the lens system relative to the position of the light source to focus the light from the light source. By using a first housing that employs both a light source, a reflector and a lens, a large amount of the light from the light source can be collimated and the light beam can be focused over a broad band (a tight to wide beam). The light-emitting device is easy to focus and relatively cost effective to manufacture.

In some embodiment, the first housing and the second housing include opposing threaded surfaces that allow the first housing to be attached to the second housing and that allow the adjustment of the position of the lens system after attachment. The latter adjustment can be made, for example, by including an element in the lens system that contacts the second housing to provide the adjustment to the position of the lens system. The lens system can be spring loaded in the front housing.

In some embodiments, the first housing further includes a heat sink that absorbs and dissipates heat generated by the light source. The light source can be mounted on the heat sink, which because it absorbs and dissipates heat from the light source minimizes the tolerance stack-up between parts.

Embodiments of the light-emitting product may include one or more of the following features. The first housing may include one or more elements that extend rearward to contact a cam surface. When the first housing is moved relative to the second housing the element through contact with the cam surface adjusts the position of the lens system relative to the light source. The cam surface may be cylindrical, as in a barrel cam. The cam surface may be located on a cup or other member that is fixed in position relative to the second housing. The cup or other member may include an external element, for example, a tooth that engages a surface of the second housing and fixes the cup or other member in position relative to the second housing. The second housing may include a surface (for example, an internal surface) having a protruding element (for example, a spline) that engages the cup or other member and fixes the cup in position relative to the second housing. The cam surface may include a stop element (for example, a vertical step) that prevents the element extending rearward from the first housing from moving further along the cam surface

In another aspect the invention features a light-emitting product the same as one of these described above but without a reflector in the first housing.

In another aspect, the invention features any of the first housings described above. In some embodiments, the first housing can be attached to a variety of second housings including a power source including, for example, a housing of a bicycle pack, head light, flashlight, etc. In other embodiments, the first housing can be used with multiple power sources, such as small or large battery packs, a rechargeable or non-rechargeable battery pack, or an AC powered system.

Other aspects of the invention include methods of assembly and methods of using the above light-emitting devices.

A “reflector” as used herein, is a member that includes a surface having a reflectance of greater than 50%, e.g., greater than about 75% of the visible light generated by the light source.

Among other advantages of one or more embodiments is a configuration which allows a user to manipulate (e.g., widen or narrow) a light beam by relative rotation of components, but is prevented from rotating the components to an extent that the components separate or move beyond a predetermined range of motion.

DETAILED DESCRIPTION

Referring toFIG. 2, first housing12includes a light source16, a reflector18, a lens system20, a heat sink22, an outer head24, a window26, an end cap28, and a lens spring30.

Light source16is an LED but alternatively can be, for example, an incandescent bulb. Light source16is mounted on heat sinks22and is fixed in position in first housing12.

Reflector18can be made of, for example, a solid single material such as a polished metal like aluminum, copper or silver, or a coated material such as metal (e.g., aluminum) coated glass or plastic. Reflector18also is mounted on heat sink22and is fixed in position in first housing12.

Lens system20includes a lens32, extending in front of light source16, and member34. Lens32is configured to collimate, focus, or widen light emitted by light source16, based on the relative positions between lens32and light source16. In one embodiment, lens32has a rounded front surface and a flat rear surface focusing light source16. Lens system20is movable relative to light source16and reflector18(see further discussion below). Lens system20alternatively can include a plurality of lenses that, together, collimate, widen, or focus light from light source16.

Heat sink22can be made of materials such as, e.g., aluminum, copper, or a heat conducting-composite, that absorb and dissipate heat from light source16. Heat sink22is fixed to outer head24.

Outer head24includes a threaded surface36. Outer head24can be constructed from metal, plastic, or other material. Member34overlaps axially with threaded surface36. Window26is mounted at the front of first housing12and detachable end cap28is attached to outer head24.

Lens spring30is mounted between reflector18and lens assembly20adjacent to the front of member24.

Second housing14includes a chamber38for batteries (not shown), a threaded surface40, and an electrical contact, which in this embodiment is a spring42, between the batteries and light source16when first housing12and second housing14are attached.

First housing12and second housing14are shown detached inFIG. 2. Referring toFIGS. 3-5, first housing12and second housing14are attached by screwing first housing12onto second housing14. Eventually, member34contacts the front of second housing14. At that point, lens32is at its closest position to light source16. As first housing12continues to be screwed onto second housing14, light source16and reflector18continue to move axially towards second housing14, but further axial movement of lens system20is constrained by the contact of member34with the front of second housing14. As a result, the front of member34compresses lens spring30which causes lens32to move further away from light source16. This results in focusing a light beam emitted from light-emitting device16(with end cap28detached) to focus from a wide beam to a narrower beam. When first housing12is fully screwed onto second housing14(seeFIG. 5), lens32is at its furthest distance from light source16.

In use, first housing12is rotated relative to second housing14to provide the desired focus. Of course, this can also be done by rotating second housing14relative to first housing12.

Referring toFIG. 6, in an alternative embodiment a flashlight40includes a front, first housing42and a rear, second housing44attached by means of threaded surfaces including threaded surface46on rear housing44. First housing42includes a statically mounted reflector48, a clear focusing lens50located centrally on the distal side of reflector48, and a light source52at the apex of reflector48proximal to lens50. Reflector48has one or more (e.g., two, three or four) radially distributed openings54. Lens50includes one or more radially distributed legs56protruding through reflector to a proximal position.

Referring toFIG. 7, reflector48is rotationally and axially constrained to a heat sink58. Heat sink58has axial legs60radially displaced from the position of openings54.

Referring toFIG. 8, a cup62with a planar circular proximal end64is located proximal to light source52. Cup62includes an annular distal end66including one or more helical cam surfaces68. Helical cam surfaces68communicates with legs56of lens50. By means of relative rotation of first housing42to cam surface68lens50is moved in an axial direction from a proximal to distal position relative to light source52, thereby causing a change in the light beam from narrow to wide angle.

Cam surface68has a proximal end70and a distal end72. At distal end72cam surface68returns to proximal end70with a nearly vertical step74, shown inFIG. 9. When a right hand thread is used on first housing42, step74on cam surface68will face in such a direction such that clockwise rotation of first housing42causes cup62to also rotate in a clockwise direction. The relative adjustment of lens50in this embodiment is such that the axial movement due to the helical travel of the thread is subtractive to the axial cam travel.

Referring toFIG. 9, a function of substantially vertical step74alternatively can be accomplished with a substantially vertical step76on cup62but separated radially from the cam. In this embodiment, cup62rotates in a clockwise direction due to engagement with axial legs60of heat sink58. The relative adjustment of lens50in this embodiment may be such that the axial movement due to the helical travel of the thread is additive to the axial cam travel.

Referring toFIG. 10, second housing44has a generally cylindrical internal surface including one or more splines78extending at least a portion of the length of the tube.

Referring back toFIG. 8, cup62has an external surface80interrupted with at least one radially protruding tooth82. Tooth82is connected to cup62via a compliant member84. Compliant member84allows compliance in a radial direction but is relatively non-compliant in a rotational direction. Tooth82further preferably is more compliant in a clockwise direction and less compliant in a counterclockwise direction.

Flashlight40can be assembled as follows. Cup62is affixed to first housing42prior to and during assembly but eventually becomes locked in portion relative to second housing44. First housing42is screwed on to second housing44by means of the threaded surface46. As first housing42progresses through its helical movement following the thread helix, legs56come to a stop against substantially vertical step74on cup62. This causes cup62to rotate with and in the same helical direction as first housing42. As first housing42and cup62further progress in the helical path, external tooth82on cup62engages internal spline78of second housing44. Further rotation of first housing42and cup62causes the tooth82to compliantly ratchet over spline78. The final movement of front housing42comes to a stop at the finish of assembly with the threads fully engaged. Legs56are now located at the bottom proximal end of cam surface68. Tooth82of cup62is engaged with spline78.

First housing42, when rotated counterclockwise, causes legs56to slide in an axial direction from proximal to distal due to the relative movement to cam surface68. Cup62is prevented from rotating counterclockwise due to compliant member84connecting tooth82to the cup62. The counterclockwise rotation of first housing42causes the first housing to follow a helical path moving in a proximal to distal axial direction. When cup62has only one cam surface68, first housing42has the freedom to rotate less than one rotation until legs56come to a stop at vertical step74. Further counterclockwise rotation is prevented as the torque applied by the user to rotate the head is transmitted from first housing42to legs56, then to vertical step74, then to compliant member84, then to the tooth82, then to internal spline78, thus preventing further rotation.

This structure and process described above provides that first housing42always remains within one pitch of the thread of being fully engaged with the body thread thus maintaining the integrity of the strength of the threaded assembly of the head to body.

Other embodiments are within the claims.