Illumination – Light source and modifier – Adjustable or repositionable modifier
Patent
1994-03-15
1995-06-20
Lazarus, Ira S.
Illumination
Light source and modifier
Adjustable or repositionable modifier
362282, 362346, 362301, 362297, F21V 700
Patent
active
054265754
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to luminaires, specifically to those for use in lighting situations in which it is not desired to achieve equal lighting at all positions illuminated by the luminaire. By the term `luminaire` is meant an apparatus which distributes, filters and/or transforms light from one or more lamps mounted in the apparatus.
It is known that in some lighting situations it is desired not to light uniformly the complete surroundings to a luminaire, but to direct the light in particular directions, for example the luminaire for a street light specifically directs in a downwards direction most of the light emitted by the lamp. The distribution of the light is fixed by the luminaire.
In some situations the fixed light distribution does not prove to be a problem. There are, however, lighting situations, such as in a subway, where a luminaire of fixed light distribution may result in either a large wastage of light to ensure that all the area is adequately illuminated, which in a subway results in a higher than necessary degree of illumination of the walls and certain parts of the floor surface, or it may result in inadequate lighting of the entire area but not wastage of light.
Theoretically it would be possible individually to manufacture each luminaire so as to give the light distribution best suited to the proposed position in which the luminaire is to be mounted. This option, however, is not feasible economically.
It is known to manufacture luminaires with two reflectors of which each can swivel relative to a fixed lamp, to vary the distribution of illumination. It is also known to vary the distribution of illumination by moving the light source relative to the reflectors.
Neither of these options gives a very satisfactory range of light distribution.
SUMMARY OF THE INVENTION
According to the present invention there is provided a luminaire comprising a frame, a luminaire comprising a frame, having at least four reflectors mounted around an aperture in the frame to circumscribe a lamp position and to reflect light emitted from a lamp when in position, and in which the reflectors are pivotable, characterised in that each of the four reflectors is angularly adjustable about an axis extending perpendicularly to the frame and has a substantially-triangular base in slidable contact with one surface of an apertured base member of the frame, and the adjacent ends of a pair of reflectors on each side of a median axis of the aperture are engaged by one of a pair of contiguous pivot members.
The luminaire may be adapted to be located about a fixed lamp, or it may itself include a socket for a lamp. The socket (and thus the lamp) may be fixed or it may be movable in the frame relative to the reflectors to vary the pattern and distribution of illumination.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be further described and explained by way of example with reference to the accompanying drawings, in which:
FIG. 1 shows a perspective view of a luminaire according to the present invention in a preferred embodiment;
FIG. 2 shows a side elevation of a lantern fitted with a luminaire of the present invention;
FIG. 3 is a side elevation of the luminaire of FIG. 1 in a position in which it throws light down, and
FIG. 4 is a scrap perspective view of one reflector in position.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings, a luminaire 2 comprises a frame 4 on to which are pivotally attached four reflectors 6, each being attached by, and pivoting about the main axis of, a pivot screw 8, being locked in position by a lock screw 20. Also attached to frame 4 is a lamp holder 10, in which is a lamp 12. Although screws are described, other forms of pivots and clamps could be used. FIG. 1 is a perspective view of what would be the underside of the luminaire when mounted, as is usual, to direct downwards the light from lamp 12.
Frame 4 is in the form of a metal box, with a hexagonal aperture 14 in the base 13 of the box. The walls 23 of the box 4 are forme
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patent: 3213271 (1965-10-01), Tolbert
patent: 4007365 (1977-02-01), Stempfle et al.
patent: 4041306 (1977-08-01), Compton et al.
patent: 4053766 (1977-10-01), Brass
patent: 4616296 (1986-10-01), Westgaard et al.
patent: 4651260 (1987-03-01), Lasker
patent: 4872098 (1989-10-01), Romano
patent: 4979086 (1990-12-01), Heinisch
D. W. Windsor Limited
Lazarus Ira S.
Sember Thomas M.
LandOfFree
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