Lantern Having Magnetic Lamp Focusing And Switching

Abstract

Lamp excitation, deexcitation, focusing and defocusing is provided in a lantern assembly by means of a single externally controlled magnet which coacts with an internal hard-wired hermetically sealed magnetic reed switch to control lamp excitation and an internal magnetic member for providing lamp position adjustment for infinite focus control. Under high current conditions a pushbutton switch may be a desired substitute for the reed switch. Suitable environmental conditions may further permit the use of slide or wiper contacts for lamp excitation control where good electrical contact between exposed metal surfaces can be readily maintained.

Description

BACKGROUND OF THE INVENTION

Numerous proposals have been made for providing both mechanically and electromagnetically adjustable focus control in portable lanterns and other lamp systems. Still other lanterns and lamp systems are known in which lamp excitation is controlled by magnetic field actuated switches including magnetic reed switches. Under conditions of high humidity or in corrosive or flammable atmospheres, for example, mechanically switched and adjusted lanterns are found to become unreliable and subject to dangerous arcing due to the great difficulty in maintaining good seals about the mechanical parts which penetrate the housing holding the electrical components and batteries. For use in underwater salvage and driving operations, lanterns which exhibit lack of watertight integrity become useless.

Known lanterns which utilize electromagnetically adjustable focus control can be made water and airtight but suffer the disadvantage of providing for only two positions of focusing without elaborate and expensive current control circuits for controlling the current passing through the focusing solenoid.

Known lanterns which utilize magnetically controlled reed switches for controlling lamp excitation are found to require either separately operable focusing means or simply do not provide for lamp focusing.

SUMMARY OF THE INVENTION

A principal object of the present invention is a lantern assembly provided with a single externally controlled magnet and an internal magnetic member for controlling both the lamp excitation and focusing.

Another principal object of the present invention is a portable lantern as immediately described above which may be made water and gastight for use in underwater operations and in hostile atmospheric environments.

A principal feature of the present invention is a single externally controlled moveable magnet adapted to coact with a freely moveable internal magnetic susceptible member coupled to a lamp for selectively positioning the lamp along the axis of a curved reflector for providing infinite focus control.

Another principal feature of the present invention is a lamp excitation switch which is controlled by the above-described single externally controlled moveable magnet.

These and other objects, features and advantages will be readily apparent from the following detailed description and accompanying drawings in which:

FIG. 1 is a partial schematic and simplified side view of a lamp assembly embodying the present invention;

FIG. 2 is a partial schematic and simplified side view of an alternative embodiment of the present invention;

FIG. 3 is a partial cross-sectional view taken along the lines 3--3 of FIG. 2;

FIG. 4 is a partial schematic and simplified side view of another embodiment of the present invention;

FIG. 5 is a partial schematic and simplified side view of another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

For the sake of clarity the invention is described using the same designations for identical features shown in each of the figures and much of the nonessential hardware has been omitted as its implementation is clearly within the skill of the art and forms no essential part of the invention.

Referring to FIGS. 1-5, the present invention is shown embodied in the form of a conventional hand held flashlight consisting of a parabolic reflector 1 mounted on one end of a hollow housing 2. Housing 2 may be of a nonmagnetic, conductive or nonconductive material and is provided with a cap 3 permitting access to its interior wherein one or more replaceable or rechargeable batteries 4 are located. It is understood that in some applications an external power source may be coupled through cap 3 and used in lieu of batteries 4 and cap 3 permanently sealed to housing 2. Alternatively, rechargeable batteries may be permanently sealed within housing 2 and the leads used for recharging them brought out through cap 3. At the vertex of reflector 1 and freely mounted for movement along the axis of reflector 1, there is provided a socket 5 in which is removably mounted a conventional incandescent bulb 6. Reflector 1 is provided with axially directed flanges 10, 11 of sufficient depth in the vicinity of socket 5 to provide adequate support to maintain socket 5 and bulb 6 in axial alignment as socket 5 and bulb 6 are moved to selected positions within a predetermined range along the axis of reflector 1 during focusing and defocusing.

The means by which the axial position of bulb 6 is moved to selected positions within a predetermined range comprises an arm 15 the left end of which is suitably attached to the rear surface of socket 5, as by spot welding. The right end of arm 15 is attached mechanically and, if arm 15 is conductive, electrically to a conventional magnetic reed switch 16. Batteries 4 are connected between the right terminal of switch 16 and socket 5. The leads to batteries 4 are of sufficient length to permit unimpeded movement of arm 15. As is well known, a magnetic reed switch comprises at least one pair of magnetic wands which are caused to make or break contact under the influence of an externally applied magnetic field. Closely adjacent the reed switch 16 there is provided a magnetic member 17 which is fixedly secured to arm 15. A magnet 20 is slideably mounted in a slotted channel 18 on the external surface of housing 2 and is adapted to be moved along a path parallel to the axis of movement of bulb 6. As shown, member 20 may be formed with a slight indentation and its upper surface 21 serrated to provide additional friction and ease of operation as is often required by persons wearing gloves or when fingers and thumbs are wet and cold as occurs in underwater operations.

In operation, magnet 20 is moved left from its "off" position as shown. The magnetic field generated by magnet 20 engages reed switch 16 causing its wands to make contact which in turn couples power into bulb 6 from batteries 4 or any external source as hereinbefore mentioned. Magnet 20 also induces an appropriately polarized magnetic field in member 17 which with movement of magnet 20 in a leftward direction causes arm 15 and hence bulb 6 to be moved leftward thereby effecting an increase or decrease in focusing or beam spread depending on where the bulb 6 is initially located relative to the focal point of reflector 1.

Referring to FIGS. 2 and 3, alternatively, magnetic member 17 may take the form of a toroid 20'. The enhanced field conditions in this form of the invention are found to permit greater control and the toroidal shape of magnet 20' permits lamp switching and adjustment without the need for rotating the lantern to reach an isolated switching member. It is understood, however, that in any of the embodiments described, the internal members 17, 17' may comprise a magnet and the external members 20, 20' may comprise a magnetic susceptible material.

It is believed important to recall at this point that the described invention may be most advantageously utilized under the most hostile conditions of dampness, corrosive and flammable atmospheres with a high degree of reliability. In this regard it is noted that in the preferred embodiment described with respect to FIGS. 1-3, there are no moveable electrical contacts which are subject to hostile environmental conditions. Reed switch 16 is comprised of wands hermetically sealed in a near vacuum. The external connections of reed switch 16 may be hard-wired or soldered to arm 15 which is in turn soldered or welded to socket 5. In like fashion each of batteries 4 may be hard-wired to each other as well as to socket 5 and reed switch 4. Thus even when housing 2 is worn or damaged and gas and watertight integrity is lost, there is no damage to or corrosion of any electrical contacts. Nor is there the danger of arcing which would prevent use of the lantern in flammable atmospheres. At the very worst, the drain on batteries 4 may be accelerated due to lower resistance paths between exposed conductive surfaces which may be compensated for by adequate insulation.

Referring to FIG. 4 there is shown an alternative embodiment of the present invention wherein a conventional pushbutton switch 26 is used in lieu of magnetic reed switch 26 described with respect to FIG. 1. Pushbutton switches, while considerably more subject to failure due to mechanical wear and contact exposure to hostile environments, may be used to advantage in high current applications which are beyond the capability of presently available magnetic reed switches. In a similar manner as described with respect to FIG. 1, magnetic member 17 is mounted on arm 15. Arm 15 is in turn mounted on socket 5 and is adapted to move bulb 6 axially left and right under the influence on the magnetic field of and in response to the left and right movement of magnet 20. In this embodiment, however, pushbutton switch 26 is mounted adjacent the path of movement of magnetic member 17. Magnetic member 17 is formed to provide a downwardly projecting surface 27 which is caused to come into contact with an upwardly directed actuating button 28 projecting from the upper surface of switch 26 as magnetic member 17 is moved leftward. Magnetic member 17 is of sufficient length to maintain button 28 in a depressed or "on" condition for all positions of bulb 6 except when magnetic member 17 is in its leftmost position as shown. Switch 26 is otherwise electrically connected to a source of power, such as batteries 4 and to socket 5 in a conventional manner.

In FIG. 5, there is shown a further and more economical embodiment of the present invention which may be used to advantage in environments in which electrical contact problems are minimal. As shown, a sliding-contact switch assembly 36 is used in lieu of magnetic reed switch 16 and pushbutton switch 26 described above with respect to FIGS. 1 and 4, respectively. Switch 36 comprises a fixed electrically conductive member 37 mounted to the interior surface of housing 2. The left end of arm 15, on which magnetic member 17 is mounted is extended somewhat and formed to provide an upwardly directed contact 38 which will make electrical contact with and slide along member 37 as magnetic member 17 is moved leftward under the influence of the magnetic field of and in response to the movement of magnet 20. In a conventional manner, a source of power, such as batteries 4 is series coupled to socket 5 through switch 36. If housing 2 is made of electrically conductive material, member 37 is mounted on housing 2 using insulating blocks (not shown) and an insulating pad 39 is provided at the right end of member 37. In its rightmost or "off" condition, contact 38 will rest on pad 39 and will not be in electrical contact with member 37 and the source of power 4 will be decoupled from socket 5.

It is understood that while flanges 10, 11 are sufficient to support and maintain the axial alignment of socket 5 and arm 15 in many cases, the inclusion of additional support in any well-known manner may be necessary in larger embodiments.

Claims

I claim:

1. In a lantern having a source of electromagnetic energy adapted to be coupled to a source of power and free to move along the axis of a curved reflector partially surrounding said source, the improvement comprising:

a hollow housing disposed on the convex side of said curved reflector;

an external selectively moveable member mounted on the exterior surface of said housing; and means mounted within the interior of said hollow housing and to said source of electromagnetic energy to move said source of electromagnetic energy to any desired position within a predetermined range along the axis of said reflector in response to the movement of said external member, wherein one of said member induces a magnetic field in the other of said member.

2. In a lantern according to claim 1, an electrical switch means mounted within the interior of said hollow housing and adapted to be actuated in response to a predetermined movement of said external member for coupling said source of electromagnetic energy to a source of power.

3. In a lantern according to claim 2 wherein said electrical switch means in a magnetic reed switch, said external member is a magnet and said internal member is a magnetic susceptible member.

4. In a lantern according to claim 3 wherein said internal and external members are in the shape of a toroid.

5. In a lantern according to claim 2 wherein said electrical switch means is a pushbutton switch.

6. In a lantern according to claim 2 wherein said electrical switch means comprises a sliding contact switch.