Miniature low-voltage lighting fixture

A lighting fixture includes a reflector lamp having a bulb, a reflector and a bayonet base, a lampholder for holding and connecting the lamp having a proximal end connected to an external source of electrical power and a distal end supporting the base of the lamp. A generally radial flange is contiguous with the distal end of the lampholder and supports a contiguous cylindrical bulb reflector housing coaxially with the lampholder and extends beyond the bulb reflector in the distal direction. The bulb reflector has one or more rotational engagement notches engageable with a tool for installation or removal of the bayonet base of the lamp from the lampholder. A preferred embodiment has a torsion spring is disposed about a screw installed in each of two threaded transverse holes, with the springs having legs resiliently biased towards the distal end of the fixture. The cylindrical bulb reflector housing extends beyond the bulb reflector and is provided with an external radial flange at its distal end; whereby the fixture may be installed in a hole in a ceiling panel that closely fits the bulb reflector housing and the legs of the torsion spring apply force to a top surface of the ceiling panel to pull the external radial flange against the bottom surface of the ceiling panel to retain the fixture in the panel.

BACKGROUND OF THE INVENTION 
This invention relates to lighting fixtures for use in residential and 
commercial applications, and particularly to those fixtures that use 
miniature reflector lamps for precise control of the light beams. 
Presently available light fixtures for such applications are generally 
complex, such as is shown in U.S. Pat. No. 4,646,214, in which a 
lampholder is installed into one of three separate housings that comprise 
the fixture. A major reason for the separable housings is to provide 
access to the bulb. A step towards simplification was made in my U.S. Pat. 
No. 4,682,276 in which the lampholder is integral with the housing, but 
the housing requires radial clearance to grip the bulb reflector for 
removal or replacement of the lamp. A reflector for a lamp that requires 
virtually no radial clearance is shown in my co-pending design patent 
application Ser. No. 198,095. 
A primary purpose of the present invention is to provide a simple and 
inexpensive one-piece structure for a lighting fixture for reflector 
lamps, in which the bulb may be easily removed and replaced without 
resorting to separable housing sections or excessive radial clearance for 
bulb access. 
It is a further purpose of the present invention to provide a lighting 
fixture that is easily mounted in a ceiling panel with no loose parts or 
external supports. 
SUMMARY OF THE INVENTION 
The achievement of the foregong purposes of the invention are achieved by 
the present invention in which a miniature lighting fixture includes a 
reflector lamp having a bulb, a reflector and a bayonet base. The 
structure for the fixture includes an integral lampholder for holding and 
connecting the lamp, with a proximal end connected to an external source 
of electrical power and a distal end supporting the base of the lamp. A 
generally radial flange is contiguous with the distal end of the 
lampholder and supports a contiguous cylindrical bulb reflector housing 
coaxially with the lampholder and extending beyond the bulb reflector in 
the distal direction. A plurality of generally planar fins are integral 
with the lampholder, the radial flange and the cylindrical bulb reflector 
housing. The integral fins are parallel to the central axis of the 
lampholder and form a parallel plane on either side of the lampholder in 
which a threaded transverse hole is provided. 
A preferred embodiment for recessed mounting has a torsion spring disposed 
about a screw in a threaded hole one each side of the fixture, with spring 
legs resiliently biased downwards. The housing is provided with an 
external radial flange at its distal end; whereby the fixture may be 
installed in a circular hole in a ceiling panel that closely fits the bulb 
reflector housing. The legs of the torsion spring are flexed upwards and 
the fixture body is slipped into the hole in the ceiling. The torsion 
springs arethen released to apply force to the top surface of the ceiling 
panel to pull the radial flange of the fixture upwards against the bottom 
surface of the ceiling panel to retain the fixture in the panel. 
In another preferred embodiment the bulb reflector has one or more 
rotational engagement notches for installation or removal of the bayonet 
base of the lamp from the lampholder. An installation and removal tool 
engages the notches with planar vanes that are provided at one end of an 
elongated handle that permits installation or removal of the bulb from a 
ceiling-mounted fixture while standing on the floor.

DETAILED DESCRIPTION OF THE DRAWINGS 
In FIG. 1 a preferred embodiment of the low-voltage lighting fixture 1 has 
a lampholder 2 for holding and connecting a lamp 3 on a central axis 4. 
Lampholder 2 has a proximal end 5 having a means 6 for connection to a 
source of external electrical power, and a distal end 7 contiguous with a 
flange 8 which extends radially to a cylindrical lamp reflector housing 9 
extending beyond the bulb reflector in the distal direction. A plurality 
of integral fins 10 are contiguous with the lampholder 2, the flange 8 and 
the cylindrical reflector housing 9. Lamp 3 is a miniature reflector lamp 
generally known as an "MR" type, and is provided with an exposed bulb 11. 
In FIG. 2 fixture 1 is shown in cross section with lamp 3 having a 
conventional bayonet base provided with cross pins 12A and l2B axially 
slidable in channels 13A and 13B and rotated into a pair of recesses 14A 
and 14B which intersect the channels in a manner typical of bayonet base 
sockets. The means 6 for connection to a source of external power includes 
a insulated conductors 16 passing into the proximal end of lampholder 2 
and connecting to a contact plate 17 axially slidable in channels 13A and 
13B and resiliently urged into contact with the lamp base 4 by a spring 
18. 
In FIG. 3 fixture 1 is shown with the generally cylindrical lamp reflector 
housing 9 having a radially extending flange 20. 
In FIG. 4 fixture 1 is shown with both the reflector housing 9 and cooling 
fins 10 having generally cylindrical surfaces terminating in the flange 
20. The cooling fins are optional, based on the required cooling for 
higher lamp power applications. 
In FIG. 5 lamp 3 is shown having a reflector 21 and bayonet base 4 with 
cross pins 12A and 12B and having a means for bulb installation and 
removal comprising a pair of notches 22A and 22B in the edge of reflector 
21 and engageable with a pair of drive blades 23A and 23B on a key 24, 
whereby the bayonet base pins 12A and 12B may be rotated into engagement 
or out of engagement with the respective recesses 14A and 14B of the 
lampholder of FIG. 2. 
FIG. 6 shows a preferred embodiment fixture 25 for recessed ceiling 
installation in which a threaded hole 26A is provided to secure a torsion 
spring 27A rotatable on a screw 28A on one side of the fixture, and 
another threaded hole 26B is provided to secure a torsion spring 27B 
rotatable on a screw 28B on the opposite side of the fixture. Torsion 
springs 27A and 27B are shown in a free condition. Screws are shown as one 
means of providing a pin for holding the torsion springs, but any other 
means, such as drive pins, integral bosses or rivets will provide an 
equivalent function. 
In FIG. 7 fixture 25 is shown having torsion springs 27A and 27B 
torsionally loaded in the directions shown by the arrows to a dimension 
that will permit the springs to pass through a hole 30 in a ceiling panel 
which is large enough to permit the entry of the cylindrical reflector 
housing 31 of Fixture 25, but not large enough to accept the radial flange 
32. 
In FIG. 7 fixture 25 is shown installed into a generally circular hole 30 
in a ceiling panel 31 having a top surface 33 and a bottom surface 34. 
Hole 30 is large enough to accept the cylindrical reflector housing 35, 
but is not large enough to accept radial flange 36. The internal structure 
of fixture 25 is identical to that of fixture 1 shown in FIG. 2, and 
fixture 25 is provided with a lamp 39 which is identical to the miniature 
reflector ("MR") lamp 3 of FIG. 2 and has an exposed bulb 41 and a pair of 
notches 40A and 40B. 
The installation of fixture 25 into the ceiling is shown in FIG. 8 in which 
housing 35 is disposed within hole 30 with flange 36 held tightly against 
bottom surface 34 of ceiling panel 31 by the urging of the torsion springs 
27A and 27B in the direction shown by the arrows against top surface 33 of 
ceiling panel 31. 
Since most ceilings are manually unreachable from the floor of a room, FIG. 
9 shows a preferred embodiment of a relamping tool 42 for removal and 
replacement of bulb 38 (or bulb 3 of FIG. 2) including a pair of blades 
43A and 43B engageable with lamp notches 40A and 40B, respectively, and a 
resilient tube 44 frictionally engageable with bulb 41. Tube 44 is fixed 
to a support 45 that is contiguous with an elongated handle 46 extending 
to a grip portion 47. In operation relamping tool 42 is inserted into the 
fixture with tube 44 engaging bulb 41 and blades 43A and 43B engaging 
notches 40A and 40B. respectively. The tool is rotated to release the lamp 
and the lamp is withdrawn from the fixture with tube 44 holding the bulb 
41 (bulb 11 of FIG. 1) so the lamp 39 (lamp 3 of FIG. 1) will not fall 
from the tool. A new lamp may then be placed on tool 42 with the bulb held 
frictionally by tube 44 and lamp notches engaged onto blades 43A and 43B. 
The new lamp is inserted into the fixture and rotated to lock it in place. 
Then tool 42 is pulled loose from the bulb and the fixture is relamped.