Note: Descriptions are shown in the official language in which they were submitted.
106ZZ21
Background of the Invention
This invention refers to spot-light reflectors and has several
objects. One of its objects is to provide a spot-light combining
great simplicity and efficiency so that a large portion of the
light emitted from the incandescent filament of an incandescent
lamp is directed to the spot intended to be illuminated. Another
object is to provide spot-light reflectors allowing to use in-
candescent standard lamps, i.e. reflectors which are not limited
to special spot-light lamps. Still another object of the invention
10 is to provide reflectors which are made up of a main reflector
body and of an auxiliary reflector body and in which the latter is
readily removable to facilitate the replacement of burned-out
incandescent lamps. A further object of the invention is to mini-
mize the portion of the total light emission of an incandescent
lamp which is converted into heat.
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Summary of the Invention
, A spot-light reflector structure for incandescent lamps accord- - --
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ing to this invention comprises a substantially parabolically
- shaped member forming both the outer casing for an incandescent
20 lamp and also forming a parabolic reflector for light emitted from
said lamp, said member having a central aperture in the apex region
thereof adapted to receive the neck of an incandescent lamp, and
said member further having a cylindrical rim at the end thereof
opposite said apex region forming an open duct. A spot-light re-
flector according to this invention comprises a substantially fully
hemispherical auxiliary reflector arranged in coaxial relation to
-~ said parabolically shaped member and adapted to be positioned in; front of the bulbous portion of an incandescent lamp and to re-
flect light emitted from said incandescent lamp in forward direction
30 back to said parabolically shaped member. A spot-light reflector
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-~ according to this invention further includes an arm biased by a
- helical spring being pivotally supported at one end thereof ad-
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;- jacent said rim of said parabolically shaped member and supporting
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`` 106Z'~21
on the other end thereof said auxiliary reflector, said arm
allowing said auxiliary reflector to be pivoted in such a way
as to allow substitution of an incandescent lamp or another.
The above referred-to auxiliary reflector has an opening therein
in the peak region thereof. A tubular extension substantially in
the shape of a paraboloid of rotation has one end which is co-
`. extensive with said opening of said auxiliary reflector, pro-
jecting from said opening, and having a light reflecting inner
surfs~e.
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Brie~escription of the Drawings
Fig.l is substantially a vertical section through a spot-light
embodying this invention with a standard incandescent lamp placed
into it; and
Fig.2 is a partial bottom-plan view of the structure shown in
Fig~lo
Description of Preferred Embodiment
--
In the drawings reference numeral 1 has been applied to indicate
a main reflector body which is curved substantially parabolically,
10 i.e. has substantially the shape of a paraboloid of revolution.
The reflector body 1 proper is provided on its lower wide end with
a cylindrical rim lc which forms an integral part of the main re- ~ -
flector body 1 proper. Reflector body 1 defines a central aperture
e in the peak region thereof. The lamp socket 2 indicated dia-
grammatically is arranged outside of reflector body 1 and receives
the screw-threaded portion 3a Of the neck of an incandescent lamp
3. An annular member 5 encompassing slightly less than 360 deg. is
arranged inside of cylindrical rim lC. The ends 5a Of member 5
~?~ are bent inwardly and arranged in parallel relation and form a
20 supporting bracket~ Member 5 is flexible and tends to expand
- and is, there~ore,maintained by friction inside of rim lC~ Stud
or rivet 8 projects transversely through supporting bracket 5a
and supports an arm 6 and a helical biasing spring 7. Arm 6 is
pivotable about stud 6 and projects radially inwardly from its
point of support. The radially inner end of arm 6 supports a
- substantially hemispherical auxiliary reflector body 4 defining
a central aperture 4a which is arranged substantially in registry
~, with the aperture le in the main reflector body 1. One end of
helical ~ ~ ring 7 rests against pin ld on member lc and
30 the other end of spring 7 rests against an abutment 6a on arm 6.
As a result, arm 6 and reflector 4 are biased in counterclockwise
direction as seen in Fig.l and the latter envelopes the bulbous
bo~tom po~t~on 3b Of the incandescent lamp 3~ The arrangement is
106Z2Zl
made such that the auxiliary reflector body 4 does not physically
engage the bulbous portion 3b Of the incandescent lamp 3, but that
a small gap C is left between both of them. Lever 6 may be pivoted
in clockwise direction as seen in Fig.l against the bias of spring
7 to get access to lamp 3 in order to replace the same. Spring 7
further tends to increase the spacing between the parallel bracket
arms 5a, as a result of which the annular element 5 is expanded and
engages more firmly the cylindrical portion lc of main reflector 1.
The width of element 5 may be narrower than shown iQ the drawing, as
lO a result of which the structure 4-8 may be slightly moved in axial
direction so to adjust the width of gap C between auxiliary re-
flector 4 and the bulbous portion 3b of incandescent lamp 3. Such
f an adjustment of gap C if proper precludes an overheating of in-
candescent lamp 4 and a consequent reduction of the life thereof.
As shown in Fig.l light rays emitted from the incandescent
filament 3c of lamp 3 are reflected from the parabolic surface
thereof in parallel direction as indicated at xl and x2.
Light rays which are emitted from filament 3C rearwardly within
the space of the cone A having the angle ~ leave the main re-
20 flector body 1 by way of aperture le and are ultimately absorbed
and converted into heat. However, light rays which are emitted
; from filament 3c forwardly within the space of the cone B having
the angle B pass through the central aperture 4a in reflector
body 4 and used to illuminate the area intended to be illuminated.
As shown in Figol auxiliary reflector 4 has a tubular extension
; 4b projecting forwardly from central aperture 4a and has a light
reflecting inner surface which is shaped substantially para-
bolically, i~e. has the shape of a parabol0id of revolution. There-
fore light rays incident on the inner surface of tubular ex-
; 30 tension 4b are reflected forwardly, i.e. parallel to light rays
xl and x2. One such light ray is shown in Fig.l and indicated by
the reference character z.
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106Z221
The incandescent lamp 3 may be slightly shifted axially in
forward or rearward direction as indicated by the dual arrow u.
Thus the filament 3C may be slightly adjusted relative to the
focal point of the main reflector body 1. Such shifting allows
to vary the direction of light rays xl and x2 from strict
parallelism to slight divergence. The adjustment of the filament
3c Of lamp 3 may be coupled with an adjustment of the reflector
body 4 (not illustrated in the drawing) which results in greater
efficiency, irrespective of whether a slightly divergent or a
strictly parallel light beam is desiredO
As clearly shown in Figol the region lb of the main reflector
body 1 immediately adjacent the central aperture le thereof is
curved non-parabolically in axial inward direction. As a result
of this configuration, light incident UpOQ the region lb of re-
flector body 1 is not entirely lost, but reflected forwardly as
indicated by the light ray y. It is apparent that if the peak
region of reflector body 1 were parabolic rather than deviating
from the strictly parabolic shape, as shown in Fig.l, light
rays incident upon the peak region of the main reflector body 1
would be reflected back into the cavity defined by reflector
body 4.
The diameter of the aperture 4a in the auxiliary reflector
body 4 may be in the order of 1".
The parts 4 and 4b might be affixed to main reflector body 1
by means other than those shown in the drawings, though the means
shown therein is the preferred mode of embodying this invention~
As an alternative, parts 4 and 4b might be affixed to main re-
flector body 1 by means of a louvre structure supporting the
first mentioned parts in the center region thereof.
As mentioned before, the reflecting surfaces of main reflector
- body 1 and of the tubular extension 4b Of auxiliary reflector
body 4 are both curved substantially parabolically. The focal
10622Zl
points of the main reflector body 1 and that of the tubular ex-
tension 4b of auxiliary reflector body 4 ought to coincide as far
as this is feasible.
It will be apparent from the foregoing that the bundle of light
rays passing through aperture 4a form a desirable addition to the
- light rays reflected from the inner surface of main reflector body
.` 1.
The incandescent filament 3C of the incandescent lamp 3 may
be considered to approximate a point light source. The diameters
10 of the two apertures le and 4a ought to be substantially pro-
portional to their distances from the incandescent filament 3c in
` order to fully achieve the ends of this invention.
The loss of light is practically limited by the size of the
aperture le in the main reflector body 1 which is relatively small,
even if standard lamps are used whose neck is of larger diameter
than that of special lamps intended for the purpose in hand.
4' The mechanism which has been described above assures that
the movable parts 4,4b always return to their proper axial
positions, so that no misalignment thereof can occur and no ad-
~; 20 justment thereof is ever necessary.
j It will be apparent from the above that member 1 is substantial-
; ly parabolically shaped forming both the outer casiog for in-
candescent lamp 3 and a reflector for light emitted from lamp 3.
Member 1 has a central aperture le in the apex region thereof
adapted to receive the neck of incandescent lamp 3. Member 1 has
further a rim lc at the end opposite to aperture le forming an open
duct. Reflector 4 is a substantially fully hemispherical reflector
arranged in coaxial relation to member 1 and adapted to be positioned -~
in front of the bulbous portion of incandescent lamp 3 and adapted
~^ 30 to reflect light emitted from lamp 3 forwardly back to member 1.
Arm 6 biased by helical spring 7 is pivotally supported at
one end thereof adjacent rim lc of member 1, and supports at the
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~ 106Z2Zl
other end thereof reflector 4. Thus arm 6 allows reflector 4
to be pivoted in such a way as to allow substitution of one in-
candescent lamp by another. The above referred-to auxiliary re-
flector 4 has an aperture 4a therein in the peak region thereof.
A tubular extension 4b substantially in the shape of a paraboloid
of rotation has one end which is coextensive with said aperture
4b. Extension 4b has a light reflecting inner surface.
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