EP0206702A2

EP0206702A2 - Lantern with adjustable reflector assembly

Info

Publication number: EP0206702A2
Application number: EP86304588A
Authority: EP
Inventors: Tor H Petterson
Original assignee: Rayovac Corp; Ray O Vac Corp
Current assignee: Spectrum Brands Inc
Priority date: 1985-06-21
Filing date: 1986-06-16
Publication date: 1986-12-30
Also published as: CA1258842A; EP0206702A3

Abstract

Two tubular, parallel light sources (11a, 11b) cooperate with concave fixed reflectors (21a, 21b) and concave adjustable reflectors (23a, 23b). When the adjustable reflectors are positioned alongside the fixed reflectors, the direct (27) and reflected rays (29) are concentrated within a directional beam. When the adjustable reflectors (23a, 23b) are pivoted round by a common adjusting mechanism, so that they are in front of the fixed reflectors (21 a, 21 b), the rays from the two sources (11 a, 11 b) are distributed over the whole 360 degrees circle. The adjusting mechanism can position the adjustable reflectors selectively within a range of positions giving beam coverages in the range between say 180 degrees and 360 degrees.

Description

BACKGROUND OF THE INVENTION

IANTERN WITH ADJUSTABLE PEFLECTOR ASSEMBLY

This invention relates generally to lighting apparatus, and, more particularly, to portable lanterns and the like having adjustable reflector assemblies.
Lighting apparatus such as portable kerosene and electric lanterns typically project light in a horizontal plane extending over 360 degrees. In most cases, this projection pattern is satisfactory. Sometimes, however, it is desirable to limit the angular extent of the lantern's projected light. For example, when such lanterns are used in camping, it is frequently desirable to limit the angular extent of the projected light, e.^g.. to 180 degrees, so as not to disturb neighboring campers.
In the past, lanterns of this kind have sometimes included shutters for limiting the angular extent of the projected light. These shutters, which typically have been in the form of a slide or door mounted on the lantern's exterior, have not proven to be entirely satisfactory. First, they are not generally arranged to redirect outwardly all light initially emitted in undesired directions. Additionally, such shutters have not permitted a convenient adjustment of the angular extent of the projected light, between a 360 degree pattern and a predetermined smaller pattern.
It should therefore be appreciated that there is a need for a lantern having an adjustable reflector assembly that permits a convenient selection of the angular pattern of the projected light, between a 360 degree pattern and a predetermined smaller pattern (e.a., 1₈₀ degrees), and that projects substantially all of the generated light such that the projected light's average intensity varies inversely with its angular extent. The present invention fulfills this need.

SUMMARY OF THE INVENTION

The present invention is embodied in a lighting apparatus such as a portable lantern having an adjustable reflector assembly that permits convenient adjustment of the angular extent of the projected light, between a 360 degree pattern and a predetermined smaller pattern. The adjustable reflector assembly is inexpensive to manufacture and convenient to use, and it redirects substantially all of the light incident on it such that the projected light's average intensity varies inversely with its angular extent.
More particularly, the lighting apparatus of the invention includes first and second light sources, preferably in the form of linear light tubes arranged in spaced, parallel relationship. First and second fixed reflectors are located generally back-to-back between the two light sources and are adapted to reflect substantially all of the light incident on them from the two sources. First and second movable reflectors are located in predetermined relationships relative to the respective first and second fixed reflectors. Adjustment means selectively moves the first and second movable reflectors between a retracted position, in which each movable reflector is aligned with the associated fixed reflector, and an extended position, in which each movable reflector is located alongside the associated fixed reflector. With the movable reflectors in their retracted positions, the lantern projects light over a 360 degree pattern, and with the movable reflectors in their extended positions, the lantern projects light over predetermined smaller pattern, e.g., 180 degrees.
In more detailed aspects of the invention, the fixed and movable reflectors are all cylindrically concave, with circular cross-sections. The fixed and movable reflectors in each associated pair have central or longitudinal axes that are coincident with each other and spaced a predetermined distance from the longitudinal axis of the associated light source.
The adjustment means includes actuator means for controllably pivoting the first and second movable reflectors about their respective longitudinal axes, to move the reflectors between their retracted and extended positions. The various reflectors, are preferably sized such that when the movable reflectors are pivoted to their extended positions, they cooperate with the fixed reflectors to reflect about one-half of the light generated by the two light sources. The resulting pattern of projected light extends over about 180 degrees. In addition, the actuator means is adapted to pivot the respective first and second movable reflectors to any selected pivotal position between their retracted and extended positions. This correspondingly controls the angular extent of the projected light.
Other aspects and advantages of the present invention will become apparent from the following description of the preferred embodiment, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a portable lantern constructed in accordance with the present invention, with an adjustable reflector assembly located generally between two spaced, vertically-oriented light tubes;
FIG. 2 is a detailed perspective view of the lantern's light tubes and reflector assembly, shown with the pivotal reflectors in their extended positions such that the lantern projects light in a 180 degree pattern;
FIG. 3 is a top plan view of the lantern's light tubes and reflector assembly, with the pivotal reflectors in their extended positions such that the lantern projects light in a 18₀ degree pattern;
FIG. 4 is a top plan view similar to FIG. 3, but with the pivotal reflectors in their retracted positions such that the lantern projects light in a 360 degree pattern;
FIG. 5 is a schematic view of the pattern of projected light the lantern provides when the pivotal reflectors are in their extended positions, as in FIG. 3; and
FIG. 6 is a schematic view similar to FIG. 5, but showing the projection pattern the lantern provides when the pivotal reflectors are in their retracted positions, as in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference now to the illustrative drawings, and particularly to FIGS. 1 and 2, this invention is embodied in a portable lantern adapted to project light in a selected angular pattern ranging between 360 degrees and 180 degrees. The lantern includes first and second light tubes lla and llb vertically arranged in spaced parallel relationship. Each light tube is adapted to project light in a 360 degree horizontal plane. The light tubes are preferably fluorescent and powered by a suitable battery (not shown) located within a housing 13 immediately beneath the tubes. The light tubes are located within a closed chamber immediately overlaying the battery housing, the chamber being defined by a bottom wall 15, a top wall 17 and an encircling transparent side wall or window 19.
A special adjustable reflector assembly is located in the closed chamber, generally between the first and second light bues lla and llb. The assembly includes first and second fixed reflectors 21a and 21b extending between the respective bottom and top walls 15 and 17, in predetermined fixed relationships relative to the respective first and second light tubes. The first fixed reflector 21a includes a cylindrically concave reflective surface facing the first light tube lla and adapted to reflect light received from it, and the second fixed reflector ₂1b similarly includes a cylindrically concave reflective surface facing the second light tube and adapted to reflect light received from it.
The reflector assembly further includes first and second pivotal reflectors 23a and 23b extending between the respective bottom and top walls 15 and 17, in predetermined pivotal relationships relative to the respective first and second light tubes lla and llb. The first pivotal reflector 23a includes a cylindrically concave reflective surface facing the first light tube lla and adapted to reflect light received from it, and the second pivotal reflector 23b similarly includes a cylindrically concave reflective surface facing the second light tube llb and adapted to reflect light received from it.
In accordance with the invention, the reflector assembly further includes a reciprocable actuator 25 for controllably pivoting the respective first and second pivotal reflectors 23a and 23b about their central or longitudinal axes, between two extreme positions. In a fully retracted position, depicted in FIG. 4, the two pivotal reflectors are pivoted to positions directly in front of their associated fixed reflectors 21a and 21b. In this fully retracted position, the reflectors intercept a minimum proportion of light emitted by the light tubes lla and llb, and the lantern projects light in a 360 degree pattern. Conversely, in a fully extended position, depicted in FIGS. 2 and 3, the pivotal reflectors are pivoted to positions alongside, i.e., angularly contiguous with, the associated fixed reflectors. In this fully extended position, the reflectors intercept a maximum proportion of light emitted by the light tubes, and the lantern projects light in an angular pattern limited to about 180 degrees.
As best shown in FIGS. 3 and 4, the fixed reflectors 21a and 21b and pivotal reflectors 23a and 23b all have reflective surfaces with circular horizontal cross-sections. In addition, each associated pair of fixed and pivotal reflectors, i.e., reflectors 21a and 23a and reflectors 21b and 23b, are arranged with their respective longitudinal axes coincident with each other. The radius of the two pivotal reflectors ^4- slightly less than that of the two fixed reflectors. Thus, when the pivotal reflectors are pivoted into their fully-retracted positions (FIG. 4), they are closely spaced to, but immediately in front of, the fixed reflectors. In this position, the pivotal reflectors prevent any light from impinging on the fixed reflectors and a minimum proportion of the light emitted by the first and second light tubes lla and llb is intercepted and reflected. Conversely, when the pivotal reflectors are pivoted into their fully-extended positions (FIG. 3), they are alongside the associated fixed reflectors and a maximum proportion (about one-half) of the light emitted by the light tubes is intercepted and reflected.
FIG. 6 is a schematic diagram showing the angular pattern and intensity of the light projected by the lantern when the pivotal reflectors 23a and 23b are fully retracted. The solid-line arrows 27 indicate the various paths of light emitted by the light tubes lla and llb in directions bypassing the reflectors 21a, 21b, 23a and 23b. The dotted-line arrows 29 indicate the various paths of light emitted by the light tubes in directions impinging on the reflectors. It will be observed that because the light tubes are spaced from the central axes of the reflectors, the reflected light passes to the side of the light tubes and thus supplements the light initially emitted directly outwardly. Substantially all of the light generated by the two light tubes is therefore projected outwardly, in a 3₆0 degree pattern.
FIG. 5 is a schematic diagram similar to FIG. 6, but showing the angular pattern and intensity of light projected Ly the lantern when the pivotal reflectors 23a and 23b are fully extended. The solid-line arrows 31 indicate the various paths of light emitted in directions bypassing the reflectors 21a, 21b, 23a and 23b, and the dotted-line arrows 33 indicate the various paths of light emitted in directions impinging on the reflectors. Again, because the light tubes lla and llb are spaced from the central axes of the reflectors, nearly all of the reflected light passes to the side of the light tubes and thus supplements the light initially emitted directly outwardly. This reflector configuration results in a light projection pattern extending over about 180 degrees.
In both the fully retracted position (FIG. 6) and the fully extended position (FIG. 5) of the pivotal reflectors 23a and 23b, substantially all of the light emitted by the two light sources lla and llb is ultimately projected outwardly. The intensity of the projected light in the latter case (180 degree pattern) is approximately double that in the former case (360 degree pattern).
As best shown in FIG. 2, each pivotal reflector 23a or 23b includes an upper pivot arm 35a or 35b located at the reflector's upper end and a lower pivot arm 37a or 37b located at the reflector's lower end. An upper pivot pin 39a or 39b projects upwardly from the upper arm, for reception in a correspondingly-sized slot (not shown) formed in the lantern's top wall 17 (FIG. 1). Similarly, a lower pivot pin 41a or 41b projects downwardly from the lower arm, for reception in a correspondingly-sized slot (not shown) formed in the lantern's bottom wall 15 (FIG. 1). The pivot pins are aligned with the reflectors' central or longitudinal axes, and they are located close to, but nevertheless spaced from, the longitudinal axes of the associated light tubes lla and llb.
The pivotal reflectors 23a and 23b are pivoted about their respective pivot pins 39a and 41a, and 39b and 41b, by means of the reciprocable actuator 25, which is located immediately above the reflector assembly. The actuator includes an elongated body 43, with its two ends being accessible from the lantern's exterior, as shown in FIG. 1. Arms 45a and 45b project laterally from opposite sides of the body, with each arm including a slot 47a or 47b adapted to slidably receive a corresponding finger 49a or 49b projecting upwardly from the respective upper arms 39a and 39b of the two pivotal reflectors.
Manually pushing the end of the reciprocable actuator 25 that faces rearwardly in FIGS. 1 and 2 moves the actuator to the position depicted in FIG. 4. Because the fingers 49a and 49b are confined within the actuator arm slots 47a and ₄7b, the pivotal reflectors 23a and 23b are automatically pivoted to their retracted positions. Conversely, pushing the end of the actuator that is visible in FIGS. 1 and 2 moves the actuator and thus the pivotal reflectors to their extended positions, as depicted in FIG. 3.
It will be appreciated that light projection patterns between 360 degrees and 180 degrees can be produced by moving the actuator 25 to positions between the two extreme positions. In particular, as the actuator is moved from the position of FIG. 4 to the position of FIG. 3, the size of the projection pattern correspondingly shrinks from its initial 360 degree pattern to its final 180 degree pattern.
The fixed reflectors 21a and 21b are preferably formed as two walls of a single element. For aesthetic reasons, this single element can further include two additional walls 51a and 5Ib (FIG. 2) such that the element has a generally tubular - configuration. The fixed reflector element is secured in its position between the lantern's bottom wall 15 and top wall 17 by a shaft (not shown) extending throughout its length.
The fixed reflectors 21a and 21b, pivotal reflectors 23a and 23b, and actuator 25 can all be conveniently formed of a suitable molded plastic material. The reflectors are coated with any suitable reflective material.
It should be appreciated from the foregoing description that the present invention provides an improved lantern having a special adjustable reflector assembly that permits convenient selection of the angular extent of the projected light, ranging between a 360 degree pattern and a predetermined smaller pattern, e.g., 180 degrees. The reflector assembly is specially configured such that substantially all of the generated light is projected outwardly, and the project light's average intensity is substantially inversely proportional to its angular extent.
Although the invention has been described in detail with reference only to the presently preferred embodiment, it will be appreciated that those skilled in the art can make various modifications to this embodiment without departing from the invention. Accordingly, the invention is defined only by the following claims.

Claims

1. A lantern comprising first and second spaced light sources (11a, 11b) adapted to project light in a 360 degree pattern; fixed reflector means (21a, 21b) located generally between the first and second light sources and adapted to reflect light received from the light sources; and adjustable reflector means (23a, 23b) located in a predetermined adjustable relationship relative to the first and second light sources and adapted to reflect light received therefrom, the adjustable reflector means being capable of selective fixing in a retracted position in which the lantern projects light in a fixed, substantially 360 degree pattern, and an extended position in which the lantern projects light in a predetermined, fixed pattern substantially less than 360 degrees.

2. A lantern according to claim 1, characterised in that the first and second light sources (11a, 11b) are elongated and have longitudinal axes arranged in spaced, parallel relationship with each other; the fixed reflector means includes first and second fixed reflectors (21a and 21B)_' are are cylindrically concave and located generally between the respective first and second light sources, with their longitudinal axes substantially parallel with the longitudinal axes of the light sources: and the adjustable reflector means includes first and second adjustable reflectors (23a and 23b) that are cylindrically concave and that have longitudinal axes substantially parallel with the longitudinal axes of the first and second light sources.

3. A lantern according to claim 2, characterised in that the longitudinal axes of the first fixed reflector (21a) and the first adjustable reflector (23a) are substantially coincident and spaced a predetermined distance from the longitudinal axis of the first light source (11a); and the longitudinal axes of the second fixed reflector (21b) and the second adjustable reflector (23b) are substantially coincident and spaced a predetermined distance from the axis of the second light source (11b).

4. A lantern according to claim 3, characterised in that, in the retracted position, the first and second adjustable reflectors (23a, 23b) are located to intercept and reflect light that would otherwise impinge on the respective first and second fixed reflectors (21a, 21b) and the reflectors cooperate to intercept and reflect a minimum proportion of light emitted by the first and second light sources (11a, 11b), such that the lantern projects light in a substantially 360 degree pattern; and in the extended position, the first and second adjustable reflectors (23a, 23b) are located alongside the respective first and second fixed reflectors (21a, 21b) and the reflectors cooperate to intercept and reflect a maximum proportion of light emitted by the first and second light sources, such that the lantern projects light in the predetermined pattern substantially less than 360 degrees.

5. A lantern according to claim 2, 3 or 4, characterised in that, in the extended position, each fixed reflector (21a, 21b) and associated adjustable reflector (23a, 23b) intercept and reflect approximately one-half of the light emitted by the associated light source (11a, 11b), such that the lantern projects light in a substantially 180 degree pattern.

6. A lantern according to any of claims 2 to 5, characterised in that, in the extended position, each associated pair of fixed and adjustable reflectors combines to form an approximate half-cylindrical reflective surface, and the associated light source is approximately aligned with the circumferential edges of the two reflectors, spaced from their substantially coincident longitudinal axes.

7. A lantern according to any of claims 2 to 6, characterised in that the adjustable reflector means further includes actuator means (25) for pivoting the first and second adjustable reflectors (23a, 23b) about their respective longitudinal axes, to selectively fix the adjustable reflectors in the retracted position or the extended position.

8. A lantern according to claim 7, characterised in that the actuator means (25) pivots the first and second movable reflectors (23a, 23b) simultaneously.

9. A lantern according to any of claims 2 to 6, characterised in that the movable reflector means further includes means (25) for selectively fixing the first and second adjustable reflectors (23a, 23b) in any selected position between the retracted position and the extended position, such that the lantern projects light over a selected angular pattern between the substantially 360 degree pattern and the predetermined pattern substantially less than 360 degrees; and the first and second adjustable reflectors are so configured that the lantern projects light at a substantially uniform intensity inversely proportional to the angular size of its projection pattern.