Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
212825-~1
TITLE
HALOGEN LAMP
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to spring balanced anm
assemblies, and more in particular to a spring balanced
arm and lamp head assembly adapted for use with high heat
intensity halogen lamp bulbs.
In recent years, the lighting industry has developed new
forms of bulbs for use in light fixtures. One such bulb
which has been particularly successful is the halogen
light bulb for use in desk lighting lamps or the like in
place of conventional fluorescent or incandescent bulbs.
Typically, these bulbs have a 50 Watt rating, and use 12
volt current. These bulbs are efficient and economical
to use, but also produce a clear crisp white light which
is stronger and more intense than light produced by
conventional fluorescent or incandescent bulbs. One
deficiency of such bulbs is that in addition to the
intense light produced, they also produce intense heat.
Because of the high heat produced by halogen bulbs, it
has only been recently that such bulbs have come to be
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used for interior lighting fixtures such as desk lamps. Their use
previously has been limited to exterior fixtures in remote positions
where they are not likely to be touched by the user or passers-by.
~ However, with the development of smaller bulbs, the desire to use
these efficient and high quality bulbs in desk lamps and the like has
increased. Unfortunately, such lamps often do not meet U.L. standards
because the heat they produce makes it potentially dangerous for the
user to touch the lamp shade in which such a bulb is placed. Also, the
high intensity of the light produced by the bulb could be damaging to
the eyes if viewed directly.
In one aspect of the invention there is provided a universal mounting
adaptor for a lamp including a base and means in the base for securing
the base to a mounting structure. The base includes a support post
offset from the securing means and a circular upstanding ring
surrounding the post and spaced therefrom to define a circular well
therebetween.
In another aspect of the invention, a universal mounting assembly for
a lamp includes a base having a first surface portion, a support post
projecting from and above the first surface portion and a circular guide
ring projecting from the first surface portion and surrounding the post
in spaced relation thereto, with the post and ring defining a circular
well therebetween. The assembly also includes a lamp arm support
having means thereon for engaging a lamp support arm and having a
lower surface including an elongated recess formed therein for
receiving the post of the base and a circular wall, complementary to the
well in the base. The circular wall is received in the well so that the
ring, well, wall and post cooperate to provide a pivot structure for the
arm support on the base.
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A further aspect of the invention provides a spring balanced lamp
comprising a base, a lamp arm support pivotally connected to the base,
a first pair of hollow tubular arms pivotally connected at one end to the
support and at their opposite ends to the first ends of the second pair of
hollow arms. A bell crank is pivotally connected to the opposite ends
of the first pair of arms about the same axis as the pivotal connection
with the second pair of arms. A first control link is pivotally connected
at one end to the bell crank and at its opposite end to the support, and a
second control link is pivotally connected between the bell crank and
the second pair of arms. Counter balance spring means is connected
between the support and the first pair of arms for maintaining the arms
in selected upright positions. The lamp also includes a lamp head
assembly and means for pivotally connecting the lamp head assembly
to the second pair of arms. The lamp head assembly includes a support
neck and means for rotatably connecting the support neck to the second
pair of arms and adapted to support a light bulb therein. A support ring
means pivotally mounts the support ring on the neck for rotation
about the neck on an axis which is located generally perpendicularly to
the axis of pivot connection of the neck to the second pair of arms. A
reflector is mounted on the ring and a shade is mounted on the ring
above the reflector.
In accordance with a particular embodiment of the present invention a
lamp head assembly for use in a spring balanced arm light fixture or the
like, includes a support neck adapted to
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be pivotally connected to the lamp head support. For
example, the support neck can be pivotally connected to
the ends of a pair of arms in a spring balanced lamp arm
assembly. The support neck concludes a socket for
receiving a high heat intensity lamp bulb such as a
halogen bulb. A support ring is pivotally mounted on the
neck for pivotal movement about the longitudinal axis of
the neck, which is preferably located at 90~ to the pivot
axis on which the neck is mounted to the support arms of
the lamp. It is noted that although the support ring
described in this application is referred to as a ring,
and is illustrated as being circular, the ring may be in
any desired shape, such as for example oval or oblong,
and it is not intended that.the word ring as used in this
application be limited to a circular form.
A light reflector is mounted on the ring on one side
thereof. The reflector has a light and heat reflecting
surface facing the bulb mounted in the neck and has a
plurality of perforations formed therein. The
perforations allow light and heat to pass through the
reflector from the bulb side thereof to the opposite
side. A translucent shade is mounted on the ring above
the reflector and is slightly spaced from the reflector.
The shade has a central opening form therein to allow
escape of heat from the lamp head. The heat will pass
from the bulb through the perforations in the reflector
to the space between the reflector and the shade. The
opening in the shade acts as a chimney allowing the heat
to escape. In addition, the perforations allow some of
the light to pass through the reflector to illuminate the
shade and produce a pleasant visual effect.
A transparent lens is mounted on the ring on the side
thereof which is opposite the shade. The ring,
reflector, lens and shade are ~;m~n~ioned and designed,
as described hereinafter, so that when they are
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assembled, they prevent direct viewing of the bulb from
the exterior of the head assembly. In addition, the
design of the ring, and the use of the perforated
reflector, insure that the sides and shade of the head
assembly remained relatively cool to the touch. In
particular, it has been found that with the construction
of the present invention using a 50 Watt halogen bulb,
the surface temperature of the lamp head assembly on the
ring and the shade does not rise above 90~C.
The lamp head assembly includes a stand-off pin which
serves multiple functions. The pin is located to prevent
the lens on the lamp head assembly from contacting a
support surface to which it might be moved when supported
on a light fixture that has movable arms. Moreover, the
pin serves as a lock to prevent removal of the support
ring from the neck of the assembly while permitting the
ring to be rotated on the neck through approximately 360~.
The lamp head assembly of the present invention is
particularly adapted for use with a spring balanced
support arm arrangement. The lamp includes a base and a
lamp arm support pivotally connected to the base. A pair
of hollow tubular arms, which serve as electrical
conductors when a halogen bulb is used, are pivotally
connected to the support at one end and to a second pair
of hollow arms at their other end. Counter balance
springs are used to allow the relative positions of the
arms to the base to be adjusted. A control link is
provided between the first and second sets of arms so
that the position of the head in the lamp head assembly
in space will remain relatively the same regardless of
the positions to which the arms are moved. Moreover, the
base for the lamp assembly is constructed such that it is
adapted to be mounted on a variety of mounting
structures, such as a mounting base, a clamp, an inclined
surface mount, or a wall mount assembly.
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The above, and other objects, features and advantages of
this invention will be apparent in the following detailed
description of an illustrative embodiment thereof, which
description is to be read in connection with the
accompanying drawings wherein:
Figure 1 is a perspective view of a spring balanced lamp
constructed in accordance with the present invention;
Figure 2 is an exploded perspective view of the upper arm
assembly for the lamp of Figure 1;
Figure 3 is an exploded perspective view of the lamp head
assembly;
Figure 4 is an enlarged side view of the base and lower
arm assembly of the lamp of Figure 1, with parts shown in
section for clarity;
Figure 5 is an enlarged side view, partly in longitudinal
section, of the upper arm and lamp head assembly;
Figure 6A is a sectional view taken along line 6A-6A of
figure 5;
Figure 6B is a top longitudinal sectional view of the neck of the lamp
head assembly and the upper arm assembly taken along line 6B-6B of
Figure 5;
Figure 7 is a bottom plan view of the perforated
reflector and translucent shade of the present in their
assembled configuration;
Figure 8 is a sectional view taken along line 8-8 of
Figure 2 showing the twist lock retention arrangement for
holding the translucent shade in the support ring;
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Figure 9 is a sectional view taken along line 9-9 of
Figure 2 showing the extension fingers of the perforated
shade supported on the flange of the support ring;
Figure 10 is a view taken along line 10-10 of Figure 8,
but with the translucent shade removed;
Figure 11 is a partial sectional view taken along line
11-11 of Figure 4;
Figure 12 is a perspective view of another embodiment of
the present invention; and
Figures 13 and 14 are perspective views of other mounting
systems for the lamp of this invention.
Referring now to the drawings in detail, and initially to
Figure 1 thereof, a spring balanced light fixture or desk
lamp 10, constructed in accordance with the present
invention is illustrated. As mentioned above, this lamp
is particularly adapted for use with a halogen low
voltage bulb.
Lamp 10 includes a support 12 adapted to be placed on the
desk or other work surface, a lower pair of spring
balanced arms 14, an upper pair of spring balanced arms
16, and a lamp head assembly 20 which contains the
halogen bulb.
In the illustrative embodiment of the invention, power is
supplied to the lamp through a transformer 22 which is
adapted to be connected to a source of 120 volt current.
The transformer reduces the current to 12 volts which is
then supplied by wire 24 to the lamp. As described
hereinafter, using low voltage current in this way arms
14, 16 themselves can serve as conductors, so that no
internal wiring is necessary in the arms.
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In the illustrative embodiment of the invention, the
support or mounting structure 12 i9 illustrated as a
heavy circular metal disk which can sit on a desk or
other work surface. The lamp of the present invention is
secured through the support structure or disk 12 by a
unique base member 26 which is adapted to pivotally mount
the lamp for rotation about a vertical axis, and is
adapted to be secured to a variety of different support
structures.
As illustrated in Figures 4 and 11, the base 26 is
slightly elongated and has a vertical cylindrical post 28
extending upwardly from one side thereof. The base has
a main surface 30 from which a circular ring 32 projects,
in the same direction as the post 28. Ring 32 surrounds
post 28 and defines a recess 34 in the surface 30
surrounding the post.
The lamp arm assembly of the invention is rotatably
mounted on base 26 by the arm support 36. Arm support 36
is a unitary solid plastic or polycarbonate structure
which has an internal well or recess 38 formed therein
which is adapted to receive the post 28 of base 26. In
addition, the lower surface 40 of arm support 36 has a
circular wall or ring 42 extending downwardly therefrom
which is generally complimentary to the recess or well 34
in base 26. With this construction, wall 42 is received
in recess 34 when post 28 is inserted in bore 38. This
arrangement permits pivotal rotation of the entire lamp
assembly with respect to base 26.
As mentioned, base 26 provides a universal mount for the
lamp. In the illustrative embodiment, base 26 is secured
to the support disk 12 by a pair of screws 43 secured in
the mounting bores 44 formed in the mounting section 46
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of base 26. This mounting section includes a recess 48
formed therein at the location of the bores 44.
In another embo~;ment of the invention illustrated in
Figure 13 base 26 is used with a clamp 300 to mount the
lamp to the edge of a work surface or desk. As seen in
Figure 13 one arm 302 of the clamp i8 received in the
recess 48 to clamp to the base to the work surface.
Recess 48 fully accommodates the arm of the clamp so that
the arm of the clamp is at least flush with the top
surface 30 of the base and does not engage the surface 40
of the arm support 36, thereby to permit free rotation of
the arm support with respect to the base. In addition,
the bottom surface of base 26 may be provided with a cork
pad 310 glued or otherwise secured thereto for protecting
the surface of the furniture piece to which it is
clamped.
In yet another embodiment illustrated in Figure 14 an
adjustable angle bracket 400 is provided which permits
the base to be mounted on an inclined surface. Bracket
400 consists of two elements 402, 404 having cooperating
serrated surfaces 406 formed thereon. Each element 402,
404 has a bore 408 formed at the center of its circular
serrated surface 406 for receiving a bolt 410. The free
end 411 is adapted to engage a threaded knob 412, thereby
to clamp elements 402, 404 together in any of a plurality
of relative positions.
Bracket element 404 has a pair of threaded bores 414
formed therein adapted to receive bolts 42 which serve to
secure the base 26 to the bracket element 404.
Bracket element 406 has two sets of threaded bores 416,
418 formed therein at right angles to each other. These
bores are adapted to receive bolts 420 which pass through
bores 422 in clamp 300 to secure bracket element 402 in
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2128~5'1
either of two angularly related positions. By this
construction the clamp 300 can be secured to an inclined
support surface, e.g. a drafting table, and the relative
position of bracket elements 402, 404 can be adjusted to
position the base 26 in a relatively horizontal position
for supporting the lamp.
Returning to Figure 1, lamp 10 includes a lower spring
balanced arm assembly 14. This assembly includes a pair
of hollow tubular arms 50 pivotally connected at their
lower ends to the arm support 36. As illustrated in
Figures 1, 4 and 11, each of the arms 50 includes a lower
integral sleeve or boss 52 which is adapted to receive a
bolt 54. The latter has a head 56 on one end which is
received in an under cut portion of one of the sleeves
52. At its opposite end bolt 54 is threadedly engaged
with a cylindrical cap 58. The latter has a finger
extension 60 which allows the user to tighten or
untighten the bolt as it is engaged with the sleeves 52.
Arm support 36 includes an extension 62 defined by a pair
of shaped wall members 63 integrally formed on the
support. Each wall 63 has a pair of integrally formed
sections 64, 66 with the latter extending upwardly above
the shank of the bolt 54.
As mentioned above, arms 50 are formed of an electrically
conductive material in order to transmit current from
wire 24 to the bulb in the lamp head assembly. As seen
in Figures 4 and 11, this is accomplished by means of a
pair of washers 68 positioned between support 36 and the
sleeves 52 of the arms 50. The washers are connected to
the wires 24 by soldering or the like. As a result, the
current in the wires in 24 enters arms 50. Preferably
arms 50 and the other metallic components of the arm
construction of the invention are coated with a non-
conductive polycarbonate material in any known process.
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As seen in Figures 2 and 11, preferably sleeves 52 are
separately formed metallic components, each of which
defines the sleeve and a stem 70 which is received in the
open lower end of the hollow tube 50. This construction
permits ready assembly and disassembly of the parts and
interchangeability of some of the parts throughout the
construction of the lamp.
The upper end of the arms 50, as seen in Figure 2, also
have bosses 52 thereon. These also are separate elements
having projections 70 which are received in the open
upper ends of the arms 50. Sleeves 52 at the upper ends
of arms 50 are pivotally connected to the lower ends of
the upper arm assembly 16. The latter includes a pair
of upper arms 72 whose ends 74 are connected to bosses or
sleeves 52 such as those previously described which have
stems 70 received in the open ends 74 of the arms.
A bell crank 76 is provided at the interconnection
between the upper and lower arms. This bell crank
includes an integral sleeve or boss 78 on one of its
arms.
A bolt 80, similar to bolt 54 previously described,
forms the pivotal connection between arms 50 and 72.
Bolt 80 includes a head 82 which engages the sleeve 52 of
one of the arms 50 and extends through the sleeves 52 and
boss 78 of bell crank 76. Its threaded free end is
engaged by the finger nut 60. By tightening nut 60, the
clamping force on the assembly can be adjusted. Since
sleeves 52 are formed of metal and are in mating contact
with each other, current supplied to arms 50 as
previously described will pass to arms 70.
In order to counterbalance the arm assembly, a spring
assembly 84 i9 provided in assembly 14. This spring
assembly includes a relatively rigid rod 85 pivotally
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connected by a pin 86 to arms 50. The pivotal connection
is preferably formed by a pair of polycarbonate sleeves
88 press fit in openings formed in arms 50 and receiving
the ends of pin 86. The latter passes through a bore
formed in the upper end of the rod 85.
The lower end 90 of rod 85 is connected to a tension
spring 92. The lower end 96 of tension spring 92 is
connected to the free end of a threaded stud 98. The
latter has a head 100 pivotally connected by a press fit
pin 102 at the apex 104 defined by the arms 64, 66.
Preferably spring 92 and a portion of rod 85 are
surrounded by a cylindrical tube 104 having a threaded
lower end 106 which threadedly engages stud 98. As a
result, sleeve 104 is held in place and serves to conceal
both the spring and the connection of spring 92 to rod
85.
Finally, a control link 110 is provided which is
pivotally mounted by a press fit pin 112 in the arms 64.
The upper end 114 of arm 110 is pivotally mounted by the
press fit pin 116 received in the arms 118 of bell crank
76. Control arm 110 will control the position of the
bell crank 76 in space, about the pivot bolt 80, as the
lower arm assembly 14 is pivoted on the bolt 54. This
will serve to keep the relative position of the arm
assembly 16 and lamp head 20 to the support surface on
which they are mounted constant, regardless of the
position to which the lower arm is moved. And, as will
be understood by those skilled in the art, the portion of
upper arm assembly 16 on the pivot defined by bolt 80 can
be varied independently of arm assembly 14.
Upper arm assembly 16 may also be spring balanced by a
spring assembly 120 similar to the spring assembly 84
previously described. As illustrated in Figures 2, 4,
and 5 the spring assembly 120 includes a relatively rigid
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rod 122 pivotally connected by a pin 124 to the arms 72
near the connection of the arms to the lamp head assembly
20. This pivotal connection can be formed by a pair or
polycarbonate sleeves 126 press fit in openings formed in
the arms 72. The sleeves 126 receive the opposite ends
of the pin 124, which passes through an opening formed in
the open end of the rod 122. The pin is retained within
the sleeves 126 because of the pivot clamp arrangement of
the upper and lower ends of the arms.
The opposite end 128 of rod 122 is connected to a tension
spring 130. The latter is connected at its opposite end,
as seen in Figure 4, to the free end of a threaded stud
130. The latter has a rear boss 132 which is pivotally
connected by a press fit pin 134 or the like to the apex
136 formed between the arms 118 and 138 of the bell crank
76. A hollow sleeve 140 is additionally provided in the
spring assembly 120. The sleeve receives a portion of
the rod 122 and surrounds the spring 130. Its end 142 is
threadedly engaged with stud 131 to hold the sleeve in
place about the spring, thereby to conceal the spring and
the connection of the spring to rod 122.
As seen in Figures 2, 5 and 6b, the upper or outer ends
146 of arms 72 have sleeves or bosses 52 which, as with
the previously described connections, are separate
elements having studs 70 received in the opened ends of
the arms. A threaded bolt 148 having a head 150 connects
the sleeves 52 to the lamp head assembly. The latter
includes a neck 151 whose rear end 152 has a bore 154
formed therein to receive the shank of bolt 148, between
the sleeves 52 at the upper ends of the arm 72. As seen
in Figure 6, the head 150 of bolt 148 is received in a
recess of the boss 52. The free opposite end of the bolt
148 is threadedly engaged with a finger nut 153 which
holds the assembly together and provides an adjustable
clamping force.
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In order to transmit electric current to the lamp head
assembly a pair of metallic washers 154 are provided in
contact between the inner faces of the sleeves 52 and the
adjacent surfaces of the neck 151 (see Fib. 6b). The
latter is formed of a plastic polycarbonate material and
is non-conductive. The washers 154 are in electrical
contact, by soldering or the like, with the ends of wires
156 which transmit the current to the socket 158 in the
lamp head assembly in which the halogen bulb 160 is
mounted.
Neck 151 is generally cylindrical in shape and has an
open free end 162. The socket 158 is bolted to the free
end 162 of the neck by screws 164 or the like. Socket
158 is of conventional and of known construction and has
a pair of diametrically opposed ribs 166 formed thereon,
as seen in Figure 6A. These ribs are used in accordance
with the present invention to prevent inadvertent removal
of the lamp head assembly as described hereinafter.
The cylindrical sleeve defined by neck 151 includes an
annular flange 167 formed therein as well as an annual
groove 168 formed between the flange 167 and socket 158.
These elements are used, as described hereinafter, to
control the position of the lamp head assembly on the
neck. Finally, neck 151 includes a mounting boss 170 in
which a control switch 172 is secured in any convenient
manner. The switch is connected to wires 156 to control
operation of the bulb.
The lamp head assembly of the present invention is
designed to insure that the surface temperature of the
lamp head, particularly its peripheral edges and top
surface, which are most likely to be engaged by hand by
the user, will have relatively low temperatures, despite
the high temperature of the bulb contained in the head.
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In addition, it is designed to prevent the user from
looking directly at an unexposed halogen bulb, since the
bright light intensity of the bulb could be damaging to
the human eye.
As illustrated in Figures 3 and 4, lamp head assem~bly 20
includes a support ring 180. As mentioned above, this
ring although illustrated as being circular, can have any
desired shape, such as oval or oblong, and the use of the
word ring is not intended to limit the configuration of
this structure.
Support ring 180 is actually formed as two rings; an
inner ring 182 and an outer ring 184 connected to the
inner ring by three radial arms 186. In addition, a
mounting sleeve 188 is provided integrally formed with
rings 182, 184. Mounting sleeve 188 has an internal bore
190 formed therein including diametrically opposed
internal grooves 192. The latter are complimentary to
bosses 166 formed on the socket 158, so that the sleeve
can only be put on or taken off of neck 150 when the
bosses 166 and grooves 192 are aligned. This will aid in
preventing inadvertent removal of the sleeve and thus the
lamp head asse-mbly 20 from the neck 150.
In order to insure against inadvertent removal, a dual
purpose stand-off pin 194 is provided. This pin, as
illustrated in Figure 5 has a threaded upper-end 196
threadedly engaged in the outer ring 184 of ring 180, at
the location of the sleeve 188. The free end of the pin
194 enters the bore 190 of the sleeve, but the shoulder
198 formed between the pin and its threaded portion 196
defines a stop which limits the degree of insertion of
the pin into the bore 190. Shoulder 198 i8 ~;men~ioned
relative to the ring such that the extreme end of the pin
194 will enter bore 190 and the groove 168 formed in the
sleeve, but will not contact the base of the sleeve.
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This arrangement permits the sleeve and thus the lamp
head assembly to rotate on the neck through 360~, but
prevents the lamp head assembly from being removed from
the neck until the pin 194 is intentionally disengaged
from the ring.
The rear end 200 of sleeve 188 has an undercut bore
portion 202 formed therein which receives flange 166 of
the neck 151. Flange 166 and undercut bore 202 are
~lmen~ioned such that the flange forms a stop against
sleeve 188 when the head is installed on the neck, so
that the groove 168 is aligned with the position of the
pin 194.
Referring again to Figure 3, it is seen that the inner
ring 182 of support ring 180 includes an internal flange
210 formed therein. The inner surface 220 of the inner
ring 182 also includes a plurality of vertical notches
222 formed in predetermined locations along its face
above the flange 210. These notches and the flange 210
serve to permit mounting of the light reflector 224 of
the present invention.
Reflector 224 is a generally semi-circular or parabolic
reflector formed of a plastic or metallic material. Its
inner face, i.e., the side facing the bulb 160, is
preferably painted or coated with a light reflective
material. The reflector has a peripheral edge portion
226 from which four fingers 228 extend. These fingers
are located to be received in the grooves or notches 222
on the inner face of inner ring 182 where they will rest
on the upper surface of the inner flange 210. In
addition, a portion 230 of the reflector is cut out, as
seen at Figure 3, in order to accommodate socket 158 and
the neck of the lamp which enters the reflector, as also
seen in Figure 5.
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In accordance with the present invention reflector 224 is
perforated with small holes throughout its entire
surface. For clarity and convenience only some of the
perforations are illustrated in the drawing, but it is to
be understood that substantially the entire surface is
perforated with these small holes.
The small holes in reflector 224 are ~;men~ioned and
selected to permit about 20~ of the light from the bulb
to pass through the reflector with the remaining 80 to 90
percent being reflected downwardly through ring 180. In
addition, the openings in the reflector permit heat
trapped beneath the reflector to flow through the
reflector for discharge to the atmosphere. This prevents
heat build-up and aids in keeping the surface temperature
of the lamp head at the desired low temperature range.
Lamp head assembly 20 includes a shade 240, preferably
formed of a translucent plastic material. In the
illustrative embodiment of the invention, the shade has
a generally pyramidal shape in cross section, defined by
a plurality of annular rings or steps. However, it is
to be understood that the shape of the shade is
decorative and can be formed in any desired shape. The
shade has an opening 242 formed therein designed to
accommodate the neck of the lamp, as seen also in Figure
5 when the shade is installed.
Shade 240 includes a central opening 244 formed therein
which permits heat to escape from the lamp head assem~bly,
and in particular from the space between the shade and
the reflector, as seen in Figure 5.
Shade 240 also includes an peripheral flange 246 which is
generally complimentary to the shape and ~;m~nsion of the
flange 210 of the inner ring 182 of support ring 180.
Flange 246 has a plurality of notches 248 formed therein
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and its top surface 25' may be slightly inclined, as seen
in Figures 8 and 9.
The inner surface 220 of ring 182 includes five inwardly
projecting teeth 250, which are adapted to overly flange
246, when the shade is installed. Notches 248 in flange
246 are located to mate with and receive the fingers 250.
This arrangement permits the shade to be received within
ring 182 so that the bottom surface 249 of flange 246
rests on the fingers of shade 224 with the neck opening
242 slightly offset from neck 188. The shade is then
rotated clockwise, as seen in Figure 3, until four of the
notches 248 overly the fingers 224 so that the fingers
enter the notches and the bottom surface 249 of flange
246 rests directly on flange 210. In this position
flange 246 is located below fingers 250 and fingers 224
are contained in notches 248. As a result, the shade is
locked in the ring and cannot be removed. And, in that
predetermined position, the opening 240 is aligned with
neck 188.
With this construction, it is not possible for the user
to look directly at the bulb 160 through the shade or
reflector, even at the points where the shade is mounted
in the support ring. In addition, because the support
ring 180 is formed as a double ring with a space between
the rings 182 and 184, the periphery of the ring 180 will
be cooled by convection air flow through the space
between the rings. Thus, the outer ring 184 is
maintained at relatively low temperatures.
A transparent protective lens 260 is also provided in
lamp head assembly 20. This lens is preferably formed
of lexan or other suitable plastic material. The lens
can be transparent, although preferably it may be
textured in order to better disburse light from the bulb.
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Lens 260 is secured to ring 180 by a peripheral support
ring 262. This ring includes an internal flange 264 on
which the lens sits.
The shape of the ring 262 is generally complimentary to
but smaller than the shape of flange 210.
Ring 262 includes a plurality of ears or tabs 264 which
extend radially outwardly from the ring. These tabs are
secured to the outer riny 187 of the lamp head assembly
by screws 266 or the like. By constructing the lens
support arrangement to the ring 180 in this manner, a
small peripheral space 185 is formed between ring 262 and
the inner face 210 of the ring to allow air flow into the
lamp head by convection for cooling. However, by this
construction, as seen in Figure 5, it is not possible to
look directly at the bulb, even from the bottom of the
lamp head assembly.
As mentioned above, pin 194 provides a dual purpose in
the invention in the present invention. As illustrated
in Figure 5, the pin provides a stand-off for the lamp
head assembly so that should the lamp head inadvertently
be moved down towards the support surface on which the
lamp is placed, lens 260 cannot come into direct contact
with the support surface. The stand-off 164 would engage
the work surface first causing the lens to remain remote
from the work surface, thereby avoiding the danger of
fire to papers on the work surface.
In another embodiment of the invention illustrated in
Figure 12, a smaller upper arm assembly is utilized. In
that case, since there are smaller leverage forces
involved in the lamp head, it is not necessary to use an
additional counterbalance spring assembly. Accordingly,
only a relatively rigid rod 290 is used in place of the
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counterbalance spring assembly. In addition, in this
embod;ment an incandescent bulb 291 rather than a halogen
is illustrated. Since this type of bulb requires 120
volt electrical service, the arms of the lamps cannot be
used as supply conductors. However, since the arms of
the lamps are hollow the current supply wires 24 may be
extended through the arms as illustrated.
Accordingly, it is seen that a relatively simply
constructed lamp and lamp head assembly are provided in
a spring balanced lamp. The lamp construction permits
the use of high heat intensity halogen bulbs at low
voltage. The construction of the lamp head assembly
insures that the surface temperature of the lamp head is
within safe tolerances and below 90 C. It also insures
that the user cannot directly view the bulb itself.
Although the invention is particularly directed to a lamp
fixture using low voltage current supply to a halogen
bulb, the identical construction can be used with a
conventional incandescent or fluorescent bulb, simply by
changing the socket and the bulb. Although illustrative
em~bodiments of the present invention have been described
herein with reference to the accompanying drawings, it is
to be understood that the invention is not limited to
those precise embodiments and that various changes and
modifications may be effected therein by those skilled in
the art without departing from the scope or spirit of
this invention.
