Virtual axis lighting fixture

A lighting fixture having a rotatable lamp assembly including a housing having a rear wall and side walls for forming an interior compartment; the two side walls having first and second arc-shaped track formed therein; and the housing having mounting means for mounting the housing. The lighting fixture further includes a support and control assembly mounted within the interior compartment of the housing, which includes a U-shaped support bracket having upper and lower arc-shaped tracks formed therein. The lighting fixture also includes first and second arc mounting plate members for movably mounting the support and control assembly on the first and second arc-shaped tracks on the two side walls for movement along the first and second arc-shaped tracks. The lamp assembly has a third arc mounting plate member for movably mounting the lamp assembly on the upper and lower arc-shaped tracks of the U-shaped support bracket for movement along the upper and lower arc-shaped tracks. The lamp assembly rotates within the interior compartment of the housing about a virtual center or virtual axis. A first servomotor drives the support and control assembly and a second servomotor drives the lamp assembly which combine to rotate the lamp assembly in a 360.degree. degree circle about a radius of curvature having a center of curvature above the lamp assembly.

FIELD OF THE INVENTION 
This invention relates to a rotatable lighting fixture having a virtual 
axis. More particularly, this virtual axis lighting fixture is compact in 
size for use in industrial, commercial and residential applications in 
which the light rays may be focused in multiple directions from a recessed 
or semi-recessed location within a ceiling, wall or floor structure. 
BACKGROUND OF THE INVENTION 
Adjustable lighting systems often include recessed or semi-recessed 
lighting fixtures. In general, these adjustable lighting systems include a 
reflector or baffle device for producing a concentrated beam of light 
directed to a particular area normally directly beneath the lighting 
fixture. Often the direction of the beam of light must be altered to 
highlight and accent objects or areas within the room for the proper 
illumination effect needed. 
Prior art adjustable, recessed lighting fixtures have been very difficult 
to adjust in manually adjustable lighting fixtures, as well as in 
motorized lighting fixtures. For example, some prior art manually 
adjustable lighting devices require the removal of the lamp or bulb before 
effecting the adjustment in directing the light beam to its proper 
location within the room to illuminate a particular object or area 
properly. Often this process must be repeated several times on gimbal or 
swivel lighting fixtures to obtain the correct illumination and light beam 
distribution of the object or area to be illuminated. Each minor 
adjustment of the lighting fixture requires removal and replacement of the 
lamp, a very time consuming process. 
Motorized lighting fixtures are also difficult to adjust as the direction 
of the beam of light must be altered several times in order to accent or 
light up particular objects or areas for the proper illumination effect 
needed. The automated movement of the lamp is only in a two (2) 
dimensional plane (or an X & Y axis only) such that the movement of the 
lamp is about a central point (+), so that pinpointing a given area is 
difficult. 
There remains a need for a lighting fixture having a virtual axis wherein 
the lamp pivots about the virtual axis or the virtual center; and the 
diameter of the fixture housing will be reduced in size, such that the 
aperture of the fixture housing still allows all of the light from the 
lamp to pass out and through the fixture housing aperture. 
DESCRIPTION OF THE PRIOR ART 
Lighting fixtures that are rotatable having various designs, structures and 
configurations have been disclosed in the prior art. For example, U.S. 
Pat. No. 4,306,270 discloses an adjustable recessed electrical lighting 
fixture for a lamp. The lighting fixture is remotely controlled and 
employs motorized means for effecting adjustment of the beam of light 
emanating from the lamp. This prior art patent does not disclose the 
design, structure and configuration of the present invention. 
U.S. Pat. No. 4,931,916 discloses an apparatus for mechanically adjusting 
the lighting fixture beam azimuth and elevation for light projectors used 
in light stage shows, concerts, discotheques, film and television 
productions. This prior art patent does not disclose the design, structure 
and configuration of the present invention. 
U.S. Pat. No. 5,038,261 discloses an operating room light fixture having a 
cardanic mounting member connected to an overhead support beam by joints 
or linkages which rotate about horizontal and vertical axes. This prior 
art patent does not disclose the design, structure and configuration of 
the present invention. 
U.S. Pat. No. 4,945,459 discloses a two-axis beam steering system for 
deflecting a light beam along any selected azimuth and elevational 
direction for use in automated light fixtures. The beam steering mechanism 
is movable without limitation about a pan axis and through a range of 
180.degree. degrees about a tilt axis, by drive motors that are rigidly 
mounted to the housing. This prior art patent does not disclose the 
design, structure and configuration of the present invention. 
U.S. Pat. No. 4,736,278 discloses a lighting fixture with a rotating 
support. The lighting fixture includes a base, a cantilevered arm 
extending from the base and supporting a light, a rotatable platform, a 
motor for rotating the platform and electrical circuitry for actuating the 
light and/or the motor. This prior art patent does not disclose the 
design, structure and configuration of the present invention. 
U.S. Pat. No. 4,112,486 discloses a remotely controlled positioning device 
for adjustably supporting a light unit for movement in any direction 
throughout a wide range of motion. The positioning device is electrically 
powered by a reversible motor, the shaft of which is provided with a 
support member for supporting the light unit for rotation about the axis 
of the motor shaft. This prior art patent does not disclose the design, 
structure and configuration of the present invention. 
None of the prior art patents teach or disclose the structure and 
configuration of the virtual axis lighting fixture of the present 
invention wherein the lamp pivots about a virtual center or virtual axis, 
and the diameter of the fixture housing aperture is reduced in size, such 
that the aperture still allows all of the light from the lamp to pass out 
and through the fixture housing aperture. 
Accordingly, it is an object of the present invention to provide a virtual 
axis lighting fixture which allows the light beam and fixture to rotate 
about a virtual center or virtual axis above or below the light fixture, 
the lamp or trim plane. 
Another object of the present invention is to provide a virtual axis 
lighting fixture which provides a reduced width or smaller diameter of the 
fixture housing because the axis rotation (virtual center) is located 
above or below the lamp assembly. 
Another object of the present invention is to provide a virtual axis 
lighting fixture that requires a smaller aperture in its fixture housing 
in order to allow all of the light to pass out of the fixture housing. 
Another object of the present invention is to provide a virtual axis 
lighting fixture having a support and control assembly in which one 
assembly provides both support to the lamp assembly and controls the lamp 
assembly movement about the virtual center. 
Another object of the present invention is to provide a virtual axis 
lighting fixture which can accommodate all types of lamps for this type of 
lighting fixtures, including halogen and incandescent lamps. 
Another object of the present invention is to provide a virtual axis 
lighting fixture having a virtual center or virtual axis in order to 
provide a more compact fixture housing. 
Another object of the present invention is to provide a virtual axis 
lighting fixture having a support and control assembly for providing both 
the support and control functions so as to provide a more compact fixture 
housing. 
Another object of the present invention is to provide a virtual axis 
lighting fixture wherein the fixture housing is formed from light-weight 
stamped metals or molded from light-weight moldable plastics. 
A further object of the present invention is to provide a virtual axis 
lighting fixture that can be mass produced in an automated and economical 
manner and is readily affordable. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, there is provided a lighting 
fixture having a rotatable lamp assembly including a housing having a rear 
wall and two side walls for forming an interior compartment; the two side 
walls having first and second arc-shaped tracks formed therein; and the 
housing having mounting means for mounting the housing. The lighting 
fixture further includes a support and control assembly mounted within the 
interior compartment of the housing, and including a U-shaped support 
bracket having upper and lower arc-shaped tracks formed therein. The 
lighting fixture also includes first and second arc mounting plate members 
for movably mounting the support and control assembly on the first and 
second arc-shaped tracks on the two side walls for movement along the 
first and second arc-shaped tracks. 
The lamp assembly has a third arc mounting plate member for movably 
mounting the lamp assembly on the upper and lower arc-shaped tracks of the 
U-shaped support bracket for movement along the upper and lower arc-shaped 
tracks. The lamp assembly rotates within the interior compartment of the 
housing fixture about a virtual center or virtual axis above the lamp 
assembly 
A pair of servomotors are provided for driving the support and control 
assembly and the lamp assembly for rotating the lamp assembly in a 
360.degree. degree circle. The servomotors rotate the lamp assembly in a 
circle about a radius of curvature having a center of curvature above the 
lamp assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The virtual axis lighting fixture 10 and its component parts of the 
preferred embodiment of the present invention are represented in detail by 
FIGS. 1 through 7 of the drawings. The lighting fixture 10 includes a 
fixture housing 20 having mounting brackets 46 and 66, a support and 
control assembly 80 having a U-shaped support bracket 82 with first and 
second arc mounting plate members 100 and 110, a lighting fixture/lamp 
assembly 120, a servomotor 190 for rotatably moving the lamp assembly 120, 
and a servomotor 200 for rotatably moving the support and control assembly 
80. 
Lighting fixture 10 includes a fixture housing 20 having a rear wall 22 and 
side walls 42 and 62 for forming an interior compartment 40. Rear wall 22 
includes a rectangular opening for an access panel 26 and a plurality of 
mounting openings 28. Access panel 26 includes a square opening 30 for 
receiving electrical connection wires 142a, 142b and 154, and a plurality 
of mounting openings 32 for mounting screws 34. Housing 20 is constructed 
and formed from durable, light-weight stamped metal (e.g. aluminum, 
stainless steel, etc.) or molded from light-weight, heat resistant, 
moldable plastics. 
Side wall 42 includes an arc-shaped track or guide 44 formed therein for 
movably holding in place the first arc mounting plate member 100 therein. 
The outer surface of side wall 42 includes a first mounting bracket 46 for 
attaching fixture housing 20 to an interior lighting support structure 
(not shown). 
Mounting bracket 46 includes an upper vertical side section 48 having a 
pair of mounting openings 50a and 50b therein; a horizontal center section 
52 having an elongated rectangular opening 54 therein, being centrally 
located on the center section 52, and a pair of lower mounting tabs 56a 
and 56b for connectedly mounting the mounting bracket 46 to side wall 42. 
Vertical side section 48, horizontal center section 52 and lower mounting 
tabs 56a and 56b are all integrally connected to form the mounting bracket 
46. 
Side wall 62 includes an arc-shaped track or guide 64 formed therein for 
movably holding in place the second arc mounting plate member 110 therein. 
The outer surface of side wall 62 includes a second mounting bracket 66 
for attaching fixture housing 20 to an interior lighting support structure 
(not shown). 
Mounting bracket 66 includes an upper vertical side section 68 having a 
pair of mounting openings 70a and 70b therein, a horizontal center section 
72 having an elongated rectangular opening 74 therein, being centrally 
located on the center section 72, and a pair of lower mounting tabs 76a 
and 76b for connectedly mounting the mounting bracket 66 to side wall 62. 
Vertical side section 68, horizontal center section 72 and lower mounting 
tabs 76a and 76b are all integrally connected to form the mounting bracket 
66. 
Support bracket 82 of support and control assembly 80 is U-shaped in 
configuration, as shown in FIGS. 2 and 3, and includes a center plate 
section 84, first and second end plate sections 86 and 88, all being 
integrally connected together to form the U-shaped support bracket 82. 
Center plate section 84 has an upper arc-shaped track or guide 90 and a 
lower arc-shaped track or guide 92 formed therein. Center plate section 84 
further includes a mounting opening 94 for receiving shaft 202 of 
servomotor 200. Support bracket 82 is constructed and formed from durable, 
light-weight. stamped metal (e.g. aluminum, steel, stainless steel) or 
molded from light-weight, heat resistant, moldable plastics. 
First end plate section 86 includes a pair of wheel shaft openings 96a and 
96b formed therein for receiving wheel shafts 104a and 104b, respectively, 
of first arc mounting plate member 100. Second end plate section 88 
includes a pair of wheel shaft openings 98a and 98b formed therein for 
receiving wheel shafts 114a and 114b, respectively, of second arc mounting 
plate member 110. 
First arc mounting plate member 100 includes a center plate section 102 
having a pair of wheel shafts 104a and 104b mounted thereon, and with each 
wheel shaft 104a and 104b having a tracking wheel 106a and 106b mounted 
thereon, respectively, for movably tracking the wheels 106a and 106b 
within the first arc-shaped track 44 on side wall 42. Wheel shafts 104a 
and 104b are centrally located on center plate section 102 with each wheel 
shaft 104a and 104b being adjacent to the center plate section edges 108a 
and 108b, respectively. Second arc mounting plate member 110 includes a 
center plate section 112 having a pair of wheel shafts 114a and 114b 
mounted thereon, and with each wheel shaft 114a and 114b having a tracking 
wheel 116a and 116b mounted thereon, respectively, for movably tracking 
the wheels 116a and 116b within the second arc-shaped track 64 on side 
wall 62. Wheel shafts 114a and 114b are centrally located on center plate 
section 112 with each wheel shaft 114a and 114b being adjacent to the 
center plate section edges 118a and 118b, respectively. 
Lighting fixture assembly/lamp assembly 120 includes a halogen reflector 
lamp 122, a lamp socket member 132, a U-shaped lamp socket bracket 144 and 
a third arc mounting plate member 160. Halogen reflector lamp 122 includes 
a lamp reflector component 124 and a stem portion 126 having mounting 
means 127 thereon. Mounting means 127 are in the form of a pair of 
mounting tabs 128a and 128b or spiral/concentric grooves 130 on stem 
portion 126 for connecting to the socket receptacle 134 having cooperating 
lamp receiving means 135 therein. 
Lamp socket member 132 includes a socket receptacle 134 having lamp 
receiving means 135 in the form of a pair L-shaped mounting tracks 136a 
and 136b for use in conjunction with a receptacle mounting spring 138 for 
holding lamp 122 in place or an internal spiral receiving groove 140 for 
receiving the external spiral groove 130 of stem 126 on lamp 122. Socket 
receptacle 134 also includes an electrical connection wire 154 attached to 
the bottom section 137 of receptacle 134. 
Lamp socket bracket 144 has a U-shaped configuration and includes a 
circular and centrally located opening 146 for receiving of the socket 
receptacle 134 therein and a pair of mounting openings 148a and 148b for 
connecting to the third arc mounting plate member 160 via bolts/screws and 
nuts 150a, 152a, 150b and 152b, respectively. Although a halogen lamp 122 
has been shown, the present invention may be used with any type of lamp 
including incandescent, fluorescent, neon and the like. 
Third arc mounting plate member 160 includes a back plate section 162, a 
bottom plate section 172 and a pair of side plate sections 180 and 184, 
all being integrally connected to form mounting plate member 160. Third 
arc mounting plate member 160 includes a back plate section 162 having 
three wheel shafts 164a, 164b and 164c mounted thereon, and with each 
wheel shaft 164a, 164b, and 164c having a tracking wheel 166a, 166b, and 
166c mounted thereon, respectively, for movably tracking the wheels 166a, 
166b and 166c within the upper and lower arc-shaped tracks 90 and 92. 
Tracking wheels 166a and 166b move along the upper track 90 and tracking 
wheel 166c moves along the lower track 92. Wheel shafts 164a and 164b are 
located in the upper corners 168a and 168b of back plate section 162 and 
wheel shaft 164c is centrally located and adjacent to the bottom perimeter 
edge 170 of back plate section 162. 
Bottom plate section 172 includes a centrally located cut-out opening 174 
for receiving socket receptacle 134 therethrough, and a pair of mounting 
openings 176a and 176b for connecting to the U-shaped lamp socket bracket 
144 via the bolts/screws and nuts, 150a, 152a, 150b and 152b, 
respectively. Side plate sections 180 and 184 each have an opening 182 and 
186 therein for receiving motor shaft 192 of servomotor 190 within one of 
the openings 182 or 186. 
Servomotors 190 and 200 are provided and include motor shafts 192 and 202, 
respectively, for producing transverse and lateral movement. Servomotor 
190 and shaft 192 rotatably drive lamp assembly 120, and servomotor 200 
and shaft 202 rotatably drive support and control assembly 80. Servomotors 
190 and 200 in concurrent use with the U-shaped support bracket 82 and 
lamp assembly 120, respectively, combine to produce movement of the lamp 
assembly about a 360.degree. degree radius 14. Servomotors 190 and 200 are 
electrically connected to a power supply 210 via electrical connection 
wires 142a and 142b from a common electrical junction box 212 for 
simultaneous activation by power switch 214, as shown in the electrical 
schematic drawing of FIG. 7. 
Socket receptacle 134 is electrically connected to a power supply 210 via 
electrical connection wire 154 for activation and turning-on reflector 
lamp 122 via lamp socket 216, as shown in FIG. 7 of the drawings. 
DETAILED DESCRIPTION OF THE ALTERNATE EMBODIMENT 
In an alternate embodiment, the virtual axis lighting fixture 10' includes 
an L-shaped support and swivel bracket 260 as a component part of the 
support and control assembly 80. The L-shaped support and swivel bracket 
260 is used as an alternate part for the U-shaped support bracket 82 of 
the preferred embodiment, which then eliminates the need for arc-shaped 
tracks 44 and 64 in side walls 42 and 62, respectively, as well as 
eliminates the need for the arc mounting plate members 100 and 110 also. 
In all other respects, the virtual axis lighting fixture 10' of the second 
alternate embodiment operates and functions in a similar manner to the 
virtual axis lighting fixture 10 of the preferred embodiment. The 
remaining component parts of the virtual axis lighting fixture 10' are 
exactly the same as the component parts of the virtual axis lighting 
fixture 10 of the preferred embodiment. 
The L-shaped support and swivel bracelet 260, as shown in FIG. 10 of the 
drawings, includes a vertical wall member 262 integrally attached to a 
horizontal wall member 264. Vertical wall member 262 includes an upper 
arc-shaped track or guide 266 and a lower arc-shaped track or guide 268. 
Tracking wheels 166a, 166b and 166c of the arc mounting plate member 160 
are used for movably tracking the aforementioned wheels 166a, 166b and 
166c within the upper and lower arc-shaped tracks 266 and 268. Tracking 
wheels 166a and 166b move along the upper track 266 and tracking wheel 
166c moves along the lower track 268. 
Horizontal wall member 264 includes a centrally located swivel opening 270 
for receiving therein a swiveling mount member 272. Swiveling mount member 
includes a hollow shaft 274 for receiving therein motor shaft 282 of a 
miniature rotating motor 280. Motor 280 enables the horizontal wall member 
264 to rotate in 360.degree. degree circular motion, as shown in FIG. 10. 
OPERATION OF THE PRESENT INVENTION 
In operation, as shown in FIG. 1 of the drawings, the user turns ON the 
power switch 214 to power supply/source 210 for activating servomotors 190 
and 200. Servomotors 190 and 200 are activated in order to rotatably move 
the lamp assembly 120 continuously at a particular azimuth and elevational 
level within housing 20, or to rotatably move the lamp assembly 120 to a 
selected stationary position at a particular azimuth and elevational level 
within fixture housing 20. The servomotors combine to rotatably drive and 
move lamp assembly 120 along a 360.degree. degree circle about a virtual 
center or center of curvature 17 in order to focus and direct the light 
beam 12 from the aperture opening 38 of housing 20. This circular movement 
14 is produced in the following manner. The motor shaft 192 of servomotor 
190 is attached to opening 182 of side plate section 180 of the mounting 
plate member 160, and motor shaft 192 reciprocates transversely such that 
mounting plate member 160 moves the lamp assembly 120 via tracking wheels 
166a to 166c within the upper and lower arc-shaped tracks 90 and 92, 
respectively, in an arc-shaped path 16. 
Concurrently, the motor shaft 202 of servomotor 200 is attached to opening 
94 on center plate section 84 of support bracket 82, and motor shaft 202 
reciprocates laterally such that first and second arc mounting plate 
members 100 and 110 move the U-shaped support bracket 82 via tracking 
wheels 106a, 106b, 116a and 116b within the arc-shaped tracks 44 and 64 of 
side walls 42 and 62, respectively, as shown in FIG. 1 of the drawings, in 
an arc-shaped path 18. 
These concurrent arc-shaped movements 16 and 18 combine to produce a 
circular movement 14 about the virtual center 17 of lamp assembly 120 
moving within a 360.degree. degree circular radius, as shown in FIG. 1 of 
the drawings. 
As shown in FIG. 6, the lamp assembly 120 moves along an arc 90, 92 and at 
each end of the arc (positions 2 and 3), the entire light beam 12 passes 
out of the aperture 20a of the housing 20, without hitting the side walls 
42, 62 of the housing. Further, because the lamp assembly 120 moves about 
a virtual center 17 above the lamp assembly 120, the diameter of housing 
20 is substantially reduced. Also, as shown in FIG. 6, the lamp assembly 
120 moves along an arc 90, 92 having a radius of curvature 15, with the 
center of curvature 17 of the arc defining the virtual center or virtual 
axis about which the lamp assembly 120 moves. 
ADVANTAGES OF THE PRESENT INVENTION 
Accordingly, an advantage of the present invention that it provides for a 
virtual axis lighting fixture which allows the light beam and fixture to 
rotate about a virtual center or virtual axis above the light fixture. 
Another advantage of the present invention is that it provides for a 
virtual axis lighting fixture which provides a reduced width or smaller 
diameter of the fixture housing because the axis rotation (virtual center) 
is located above the lamp assembly. 
Another advantage of the present invention is that it provides for a 
virtual axis lighting fixture that requires a smaller aperture in its 
fixture housing in order to allow all of the light to pass out of the 
fixture housing. 
Another advantage of the present invention is that it provides for a 
virtual axis lighting fixture having a support and control assembly in 
which one assembly provides both support to the lamp assembly and controls 
the lamp assembly movement about the virtual center. 
Another advantage of the present invention is that it provides for a 
virtual axis lighting fixture which can accommodate all types of lamps for 
this type of lighting fixtures. 
Another advantage of the present invention is that it provides for a 
virtual axis lighting fixture having a virtual center or virtual axis in 
order to provide a more compact fixture housing. 
Another advantage of the present invention is that it provides for a 
virtual axis lighting fixture having a support and control assembly for 
providing both the support and control functions so as to provide a more 
compact fixture housing. 
Another advantage of the present invention is that it provides for a 
virtual axis lighting fixture wherein the fixture housing is formed from 
light-weight stamped metals or molded from light-weight moldable plastics. 
A further advantage of the present invention is that it provides for a 
virtual axis lighting fixture that can be mass produced in an automated 
and economical manner and is readily affordable. 
A latitude of modification, change, and substitution is intended in the 
foregoing disclosure, and in some instances, some features of the 
invention will be employed without a corresponding use of other features. 
Accordingly, it is appropriate that the appended claims be construed 
broadly and in a manner consistent with the spirit and scope of the 
invention herein.