U.S. patent number 3,916,249 [Application Number 05/495,684] was granted by the patent office on 1975-10-28 for dimming means for a lighting system.
This patent grant is currently assigned to Dallet Hoopes, Indevco Corporation. Invention is credited to Walter Thomas Ackermann.
United States Patent |
3,916,249 |
Ackermann |
October 28, 1975 |
Dimming means for a lighting system
Abstract
Lighting system has slave switch adapted to dim system when
master switch is thrown off then on within short time interval.
Throwing master switch on after short time interval expires instead
restores system to full brightness.
Inventors: |
Ackermann; Walter Thomas
(Watertown, CT) |
Assignee: |
Indevco Corporation (Watertown,
CT)
Hoopes; Dallet (Litchfield, CT)
|
Family
ID: |
23969597 |
Appl.
No.: |
05/495,684 |
Filed: |
August 8, 1974 |
Current U.S.
Class: |
315/73; 315/64;
315/69; 315/90; 315/313; 315/360; 337/123; 337/136 |
Current CPC
Class: |
H01K
1/70 (20130101); H01K 1/64 (20130101) |
Current International
Class: |
H01K
1/00 (20060101); H01K 1/64 (20060101); H01K
1/70 (20060101); H01K 001/64 (); H01K 009/08 () |
Field of
Search: |
;315/50,64,65,67,69,73,74,75,90,125,127,128,193,313,360,DIG.4
;337/123,125-128,130,131,136 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lawrence; James W.
Assistant Examiner: LaRoche; E. R.
Attorney, Agent or Firm: Hoopes; Dallett
Claims
I claim:
1. A system comprising an electic light-producing means, conducting
means connecting the light-producing means to a source of electric
power, and switch means in the conducting means, the switch means
being driven by a resistive wire element in series with the
light-producing means, said switch means automatically dimming the
light-producing means when the source of power is restored within
an established time interval after the source of power has been
interrupted, but not dimming the light-producing means if the
source of power is restored after said pre-established interval is
over.
2. A lighting system comprising at least two filament means
disposed in evacuated environment means, conducting means
connecting both filament means to a source of electric power, and
switch means intermediate the conducting means for one of the
filament means, the switch means being driven by a resistive wire
element in series with the two filament means, the switch means
deactivating the said one filament means when the source of power
is restored within a pre-established time interval after it has
been interrupted, but not deactivating said one filament means if
the source of power is restored after said pre-established
interval.
3. A lighting system as claimed in claim 2 wherein the environment
means comprises a glass envelope and wherein the two filament means
and the switch means are disposed in said envelope.
4. An incandescent light bulb comprising a glass envelope, a pair
of filaments supported in the envelope, a base on the envelope
having a pair of terminal means, conductive means operatively
connecting the filaments in parallel to the terminal means, switch
means connected between one side of one of the filaments and the
conductive means, the switch means being driven by a resistive wire
element in series with the filaments, the switch means
disconnecting the said one filament if the power to the bulb is
interrupted for a period of time greater than a first preset time
and less than a second preset time.
5. A dimmable lighting system comprising:
a. a filament means;
b. a master switch;
c. a slave switch comprising base means, a pair of cooperant switch
contacts, means to move the contacts relatively including a movable
element mounting one of the contacts, and resistive wire means
having one end mounted on the base means and the other end engaging
the movable element, the resistive wire means being electrically in
series with the filament means; and
d. circuit means connecting the switches and filament means adapted
when the contacts are closed to light the lighting system brightly
and when the contacts are open to light the system dimly
whereby when the master switch is opened, the resistive wire cools
and contracts and the movable element moves, moving the contacts
apart and then, after a delay, together again, and if the master
switch is closed during the delay, the system lights dimly, the
load of the dimly lit system being sufficient to maintain the
length of resistive wire contact to keep the contacts apart.
6. A lighting system as described in claim 5 wherein the slave
switch is disposed in a wafer-like disc adapted to be inserted in
the socket of a light bulb.
7. A light-dimming apparatus adapted to control the brightness of
the filament means of an incandescent light bulb including:
a. a switch comprising:
1. base means;
2. a conductive element supported on the base means extending up
from the base means and having an unsupported upper end, the upper
end being predisposed to a first position toward one side of the
switch from the element;
3. a resistive wire engaging at its upper end the upper end of the
element and secured at its lower end to the base means at a point
toward the other side of the switch from the element, the wire
being taut and insulated from the base and the element except at a
second point adjacent the upper end of the element, the wire
holding the element in a second position with its upper end toward
the said other side of the switch when the wire is cold and adapted
on passage of current to lengthen and permit the upper end of the
element to move to the first position;
4. a pair of contacts, one contact being mounted on said one side
of the switch from the element, the other contact being mounted on
the element confronting and aligned with the one contact, and
electrically connected to the resistive wire at the second
point;
5. means for moving the relative position of the contacts using the
change in length of the resistive wire so that the contacts are
normally engaged but are disengaged as the wire shortens in cooling
after the power supply to the switch is interrupted, and re-engaged
after the interruption is more than a pre-established period;
and
b. load means operatively connected to the switch and including the
resistance of the full filament means when the contacts are closed
and a greater resistance when the contacts are open,
whereby when the current is re-established prior to the end of the
pre-established period, the load means draws enough current to
maintain the length of the resistive wire such that the contacts
remain disengaged, and whereby the filament means is dimmed when
the contacts are disengaged.
8. A switch as claimed in claim 7 wherein the element is a rigid
beam, the base means includes an arched metal stip convex upwardly
and supports the bottom of the element keeping the wire taut and
the means for moving include a fixed pivot pin mounted on said
other side of the switch intermediate the ends of the element and
said one contact is below the pivot pin, whereby when the resistive
wire lengthens and the element inclines toward said one side, the
contacts form a pivot point and the base of the element slides
toward the said other side, and whereby when the current is
interrupted, the wire contracts and pulls the top of the element
toward the other side disengaging the contacts and subsequently, if
the interruption continues, causes the element to engage the pivot
pin, forcing the lower end toward the said one side and finally
causing the contacts to re-engage.
9. A switch as claimed in claim 8, wherein the switch is disposed
in a wafer-like disc adapted to be inserted in the socket of a
light bulb, the load means includes a diode disposed electrically
between the base means and the one contact, and terminal means are
disposed centrally of the disc on the top and bottom thereof, one
of the terminals being electrically connected to the one contact
and the other to the resistive wire adjacent the base means.
10. A switch as claimed in claim 7 wherein the element is a
resilient arm anchored at the base means and said one contact is
disposed on a rigid arm pivoted above the base means and the means
for moving comprises lost motion means adapted to pull the rigid
arm back toward said other side of the switch after the resilient
arm moves back a distance so that the contacts re-engage.
11. A switch adapted to control one filament of a two-filament
incandescent light bulb, the condition of the switch being
responsive to the length of duration of interruption of current
flow through the bulb and switch, the switch comprising:
a. base means;
b. a conductive resilient arm secured to and extending up from the
base means and having a free upper end, the upper end being
predisposed to a first position toward one side of the switch;
c. a resistance wire secured at its upper end to the upper end of
the resilient arm and at its lower end to the base means at a point
toward the other side of the switch from the arm, the wire being
taut and insulated from the arm except at its securement to the
arm, the wire holding the resilient arm in a second position with
its upper end toward the said other side of the switch when the
wire is cold and adapted on passage of current to lengthen and
permit the upper end of the arm to move to the first position;
d. a conductive rigid arm insulated from the resilient arm, the
rigid arm being pivotally attached to the base means at a point
spaced above the securement of the resilient arm to the base means
and extending upward alongside the resilient arm on the side
opposite the resistance wire, the rigid arm being adapted to move
in the same direction as the resilient arm;
e. contact means electrically integral with and mounted on the arms
respectively at a level adjacent their upper ends, the contact
means being closed when the resilient arm is in the first and the
second positions;
f. lost-motion means associated with the two arms and spaced down
from the contact means toward the pivot and adapted to permit the
resilient arm to move freely away from the first position toward
the second position and then to move the rigid arm with the
resilient arm so that the contacts separate as the resilient arm
leaves the first position and re-engage as the resilient arm
closely approaches the second position as the wire cools after the
current is interrupted; and
g. means electrically connecting one side of a power supply to the
lower end of the resistive wire, said one filament to the rigid
arm, the said other filament to the resilient arm, and the other
side of the power supply directly to the filaments,
whereby the resistance of the other filament by itself is
sufficient load to maintain the resistive wire at a length when the
contacts are disengaged such that the contacts remain
disengaged.
12. A switch as claimed in claim 11 wherein the lost motion means
comprise an insulating layer on the resilient arm and finger means
aligned with the layer and disposed on the rigid arm on the said
other side of the switch from the layer.
13. A switch as claimed in claim 11 wherein the switch is disposed
inside the glass envelope of an incandescent light bulb.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a dimming means for a lighting system.
More specifically, the invention relates to means by which an
incandescent light bulb can be dimmed by the intentional
interruption of the power supply for a short time period. The
invention makes the light dimmable even though it is disposed in a
conventional socket in a conventional two-wire circuit. The
invention also has application to other types of lighting systems
including fluorescent systems; however, the preferred embodiment of
the invention is with an incandescent light bulb.
2. Description of the Prior Art
In the prior art, there are showings of various devices by which a
light may be dimmed either by the socket switch itself, or by some
remote switching device. Probably the best known dimming means for
a lighting system involves the conventional three-way bulb in which
an incandescent bulb is equipped with a pair of filaments with ends
having a common contact, for instance, the center contact of the
bulb base, and having separate contacts for the two remaining ends
of the respective filaments; for instance, the brass screw base
itself, and an auxiliary contact located somewhere between the
center contact and the screw base. In operation, such a three-way
bulb is inserted into a special socket having a switch with four
positions: off, energizing one of the filaments, energizing the
other of the filaments, and finally, energizing both filaments.
Such arrangements thus require not only the special two-filament
bulb but also the special light bulb socket with the indicated
four-position switch.
Another dimming means for a lighting system is the so-called
"dimmer switch" which is substituted in the wall switch box for the
conventional switch. The dimmer switch will take one of two forms;
a high-low-off type switch wherein a diode rectifier is disposed
across the switch contacts in the intermediate or dimmed position;
and an infinitely variable rheostat-like control generally of the
type including SRC rectifier means wherein by turning the dial the
amount of power passing through the switch is regulated in a way
well known in the art. In either case, the dimmer switch involves
the expense of a special switch and the installation of the switch,
usually by a licensed electrician.
SUMMARY OF THE INVENTION
Under the present invention, there is provided means by which a
standard lamp socket and power supply may be used to establish a
dimmed condition for a lighting system. The means under the
invention invariably involves a switch provided preferably in the
light bulb itself or a special wafer inserted in the light bulb
socket between the central contact of the socket and the central
contact of the screw bulb base. In either case, the means embodying
the invention is actuated by an interruption of the power supply
for a brief period no greater than a preset period (for instance, 3
seconds). The interruption of the power supply may be accomplished,
then, by flicking the wall switch or the socket switch for the bulb
off and then on.
More specifically and yet still briefly, the dimming means herein
may comprise a special switch either in the bulb or in the wafer
described above or in a bulb-receiving adaptor. For convenience and
clarity herein, this switch is referred to as the "slave" switch,
while the wall or socket or other circuit controlling switch is
referred to as the "master" switch. The slave switch includes a
resistive wire adapted to carry the current to the light bulb. The
wire lengthens as it heats when current passes through it and
shortens when the current is interrupted. This change in dimension
manipulates the slave switch parts. Thus, turning the master switch
on immediately after an interruption maintains the wire at
intermediate length at which the bulb is dimmed. Keeping the master
switch off for longer than the preset period shortens the wire
further and turns the slave switch on so that when the master
switch is reactivated, the bulb will light at full brightness.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features and objects of the invention will be clear from a
reading of the following specifiction and examination of the
attached drawings, all of which show structure embodying the
invention. In the drawings:
FIG. 1 is a perspective view of an incandescent light bulb
embodying the invention and having part of its glass envelope
removed;
FIGS. 2 through 5 show various conditions of the slave switch
disposed in the glass envelope in the FIG. 1 embodiment, the views
being enlarged sectional views taken on the line 2--2 of FIG.
6;
FIG. 6 is an enlarged view of the slave switch in a position
rotated 180.degree. about its longitudinal axis from that shown in
FIG. 1;
FIG. 7 is an exploded view of structure comparable to that shown in
the assembled view (FIG. 6);
FIG. 8 is an enlarged sectional view taken on the line 8--8 of FIG.
6.
FIG. 9 is an enlarged sectional view taken on the line 9--9 of FIG.
6.
FIG. 10 is an enlarged sectional view taken on the line
FIG. 11 is an enlarged sectional view taken on the line 11--11 of
FIG. 6;
FIG. 12 is a schematic view showing the electrical environment of
the slave switch of FIGS. 1 through 11;
FIG. 13 is a fragmentary sectional view showing a slave switch
device embodying the invention disposed in a wafer located in a
conventional lamp socket;
FIG. 14 is a sectional view taken on the line 14--14 of FIG.
13;
FIG. 15 is a greatly enlarged view of the wafer with its top cover
removed;
FIG. 16 is a sectional view taken on the line 16--16 of FIG.
15;
FIGS. 17 through 19 are schematic views showing in diagrammatic
form the movement of the parts in the FIGS. 13 through 16
embodiment;
FIG. 20 is a schematic view showing the disposition of the various
elements in the circuit embodying the FIGS. 13 through 16
embodiment; and
FIG. 21 is a perspective exploded view of a wafer embodying the
invention on a scale comparable to that of FIGS. 15 and 16.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring more specifically to the drawings, a light bulb embodying
the invention is generally designated 10 in FIG. 1. It comprises a
screw base 12 and a center contact 14. As is conventional, a glass
envelope 16 is supported on the screw base and a glass stem 18
within the envelope 16 holds the internal structure including
filaments F1 and F2.
Embedded in and extending up from the stem 18 are the more or less
parallel filament supports 20 and 22 which are connected at the
lower ends by well known means to a common terminal, for instance,
the central contact 14. A third support 24 electrically engages the
opposite end of the filament F1, the lower end of the support being
embedded in the glass stem 18 but not electrically connected to any
part of the external contact. A stub support 26 extends upward
through the glass stem 18 and is connected at its lower end to the
screw base 12.
The slave switch, best seen in FIG. 6, generally designated 28,
comprises a base 30 which includes a vertically disposed
channel-like member 32 (FIG. 7) including a web 34 and a pair of
side flanges 36 and 38. As shown in FIG. 7, the channel-like member
32 has adjacent its lower end outwardly an extending foot 40 which
is coplanar with the web 34. Above and below the foot 40 are tabs
42 in the same plane with the flange 36, and similar tabs 44
aligned with the tabs 42 extending out beyond the flange 38 on the
opposite side of member 32. A cut-out 45 is disposed between the
tabs 44. The base 30 may be a brass stamping.
Adjacent the upper end of the base 30, the flanges 36, 38 are
formed with outwardly directed nibs 46. A rigid arm 48 is disposed
above the base and comprises a U-shaped element having parallel
arms 50 and a transverse bight 52. As shown in FIG. 7, adjacent
their lower ends the arms are formed with openings 54 which are
aligned, and in assembly engage the nibs 46 in a snug compressive
fit due to the resilience of the arms 50. This provides a somewhat
stiff pivoting relationship between the base 30 and the rigid arm
48.
Extending downward and intergral with the bight 52 is the ear 54.
The ear is apertured as at 56 and receives the central hub 58 of a
contact 60 which hub 58 is thereafter peened over to in effect form
a rivet, presenting the head of the contact 60 inward. The legs 50
are formed with inwardly struck fingers 62. The right arm 48 is
likewise formed from a brass stamping and the contact 50 may be of
titanium or steel alloy, as is conventional in contacts. An
insulation shoe 64 is provided and is of generally channel shape
including the web 66 and the flanges 68 and 70. The flange 70 has a
cut-out 72 intermediate its ends.
A resilient arm 74 is formed of stip brass or other resilient
conductive material and comprises an elongated strip 76 normally
bent or biased, as shown in FIG. 3 and perpendicular shelves 80 and
82 are formed at the upper and lower ends respectively. Each of the
shelves is apertured as at 82 and 84 respectively, the aperture 84
being somewhat larger than the aperture 83. A second contact 86,
identical to contact 60, has a hub 88 which is received into an
opening 90 and riveted therein as with contact 60. An insulating
pad 77 is bonded onto the inside face of the arm 74 intermediate
the ends.
Completing the slave switch assembly, a length of resistive wire
92, preferably of Nichrome, is provided and a glass bead 94 is
secured thereon adjacent the lower end although a tail 96 extends
onward. Nichrome is a trademark for a nickel-based resistive metal
containing chromium and iron.
In assembly, as shown best in FIGS. 6 and 2, for instance, the
rigid arm 48 is pivotally attached as described above, to the base
30. The shoe 64 is nested into the channel-shaped member 32 so that
its web 66 engages the web 34 and the cut-out 72 of the shoe is
aligned with the cut-out 45 of the base member. The resilient arm
74 is then manipulated so that the contact 86 opposes the contact
60 of the rigid arm 48 and the projection 78 extends through the
cut-out 45. The insulating shoe 64 is, in this process, aligned
with the fingers 62. The tabs 42 and 44 are then closed inward
tightly embracing the lower of the resilient arm 74 with the
insulating shoe 64 therebetween so that the units are electrically
insulated.
Finally, the length of wire 92 is threaded upward through the
aperture 84 in the shelf 82 and through the aperture 83 in the
shelf 80 and secured thereat in a mechanical and electrical
connection. The bead is at a fixed location on the wire and serves
to insulate the wire from the shelf 82, the hole 84 amply passing
the wire, but not the bead.
The resilient arm 74 is, as stated, of brass strip and is formed
with a bias so that its upper end extends leftwardly, as best shown
in FIG. 3. For simplicity in FIG. 7, the arm 74 is shown as
straight. In the securing of the wire 92 in final assembly and when
the wire is cold, the wire places a rightward stress on the upper
end of the resilient arm straightening out the arm as shown in FIG.
2 in much the same way as a bow string changes the shape of an
archer's bow.
The above-described assembly is supported in the light bulb, as
shown in FIG. 1. The foot 40 is secured adjacent the lower end to
the filament support 24 as by welding or the like fully support the
assembly 28. The projection 78, extending almost opposite the foot
40, supports the final filament suport 98 which extends upwardly
from the projection 78 but not downwardly. Finally, the tail 96
ofwire 92 is electically and mechanically secured to the stub
support 26. It can be seen that the stub support 26 does not extend
upward far enough to touch either the projection 78 or the support
98 and thus the two are electrically isolated in the absence of
other means.
With the above-described structure, the operation will be apparent
from FIGS. 2 through 5. FIG. 2 shows the slave switch 28 in its
normal position when the light bulb has been off for sometime and
is literally "cold"; i.e., at room temperature. In this position,
the wire 92 holds the resilient arm 74 practically vertical, as
shown, with the pad 77 holding the rigid arm 48 rightwardly such
that the contacts 60 and 86 engage. Thus, on closing the master
switch, electicity flows from the screw base 12 up the stub support
26, to the wire 92, to the arm 74, through contacts 86 and 60,
through the arm 48, the base 30, out the shoe 40, up support 24 to
filament F1, down support 22 to the central contact 14. Because the
arm 74 is energized, current also flows out projection 78, up
support 98 to filament F2 and down support 20 to contact 14, thus
both filaments F1 and F2 are activated.
Subsequently, when the wire 92 in heating reaches the length shown
in FIG. 3, the resilient arm 74 bends leftwardly and the leftward
movement of the contact 86 urges, by its engagement with the
contact 60, the rigid arm 48 to a leftward position due to the
natural bias of the resilient arm 74. During this time and
therafter, while the master switch continues on, both filaments F1
and F2 are activated.
If now the master switch is flicked off, the wire 92 cools (FIG.
4), shortening and causing the contact 86 to pull away from contact
60, the arm 48 remaining in its leftward position. If at this
movement the master switch is flicked on again, only filament F2
will light. This condition will remain static as long as the master
switch remains on because the current flowing through the Nichrome
wire 92 is reduced as compared to its condition when both filaments
are on, and this reduced flow is sufficient to maintain the length
of the Nichrome wire so that the arm 74 remains in the position
shown in FIG. 4 and the contacts 60 and 86 stay open.
If now the master switch is thrown off and remains off for a period
of time exceeding a pre-established period of time, for instance,
three seconds, the wire 92 will cool sufficiently to draw the arm
74 rightward (FIG. 5) so that the pad 77 engages fingers 62 to
mechanically pivot the rigid arm 48 rightwardly about the nibs 46.
The pad 77 and the fingers 62 thus comprise a lost-motion device,
the arm 74 thereby moving the arm 48 only after the arm 74 itself
has moved rightward some distance. Because of the location of the
finger 62 close to the pivot 46, and the distance of the contacts
60 far away therefrom, the mechanical advantage of this arrangement
causes the movement of the upper portion of the rigid arm 48 back
over a greater distance than that traversed by the pad 77 in the
process so that the contacts 60, 86 are brought into re-engagement.
Thereafter, i.e., after the wire 92 is cooled, it is in the
condition of FIG. 2 so that future closing of the master switch
causes the activation of both filaments F1 and F2.
It will thus be seen that the embodiments described in connection
with FIGS. 1 through 12 make possible, using a conventional
lighting circuit and a conventional bulb socket, means by which the
light 10 may be remotely dimmable by the master switch in the
circuit. Clearly, the structure of slave switch 28 may be disposed
outside of a conventional three-way bulb with appropriate
alternations to the circuit shown in FIG. 12. However, the
preferred use of the assembly is inside the glass envelope of an
incandescent light bulb, as shown.
FURTHER EMBODIMENT
An embodiment of the invention which may be readily disposed in a
wafer is represented in FIGS. 13 through 21. Referring to FIG. 13,
a wafter embodying the invention is generally designated 110. As
shown, it may be disposed in the socket S between the central
contact CS of the socket and the central contact CB of the lamp
base. The thinness of the wafer 110 permits the screw base of the
bulb B to be partly screwed in.
As viewed in FIG. 15, the wafer comprises a generally disc-shaped
body 112 of hard insulating material, preferably plastic. It is
superposed by an insulating cover 114 which is coextensive with the
body 112 and has a central aperture 116 over which fits the cap
terminal 118 of metal. The body 112 is formed with a recess 120 of
generally rectangular shape but having a side-wise enlargement as
at 122, as shown. Centrally of the wafer, the body is provided with
an opening 124, preferably of the same size as the opening 116. In
the opening is mounted the metal terminal cap 126, preferably
identical with cap 118. Cap 126 is formed with openings 126a and
126b (FIG. 21) to receive wires of other elements (132, 146) in
soldered connection. In the wafer is the slave switch generally
designated 128.
Threadedly disposed in a suitable tapped bore 129 intersecting the
recess 120 and extending from the outside of the wafer is a contact
screw 130. Preferably, the slot of the screw is accessible through
the bore 129 from the outside to adjust the position of the screw.
A wire 132 electrically connects the cap 126 and the screw 130 so
that the end of the screw becomes an electrical contact surface. A
second screw 134 is provided in a second tapped bore 136 and its
slot also is accessible from the outside of the wafer for
adjustment purposes. Preferably, as shown, the screw 134 may be on
a diameter of the wafer. The bore 136, as shown, intersects recess
120. It is desirable that the screws 130 and 134 be in the same
plane, a plane parallel to the surfaces of the wafer and preferably
bisecting the wafer.
As shown in FIG. 15, a slot 138 is formed across the wafer
intersecting the recess 120. In the slot is snugly disposed a base
plate 140. As shown in FIG. 15, the plate is apertured as at 142
and 144. Aside from the base plate 140, the base means includes an
upwardly H-shaped spring 145 (FIG. 21) strip of brass which rests
on the conductive plate 140. A diode rectifier 146 is electrically
connected between the cap 126 and the base plate 140. A conductive
element comprises a metal beam 148 which is rounded at its ends, as
shown, and comprises (FIG. 16) a medical web 150 and the side
flanges 152 and 154. A contact disc 156 is mounted at the side of
the beam 148 and is electrically integral therewith (FIG. 21).
In the embodiment of FIGS. 13 through 21, the resistive wire 158 is
provided with a glass bead 160 intermediate its major length and
the tail 162. In assembly, the wire, which may be Nichrome wire, is
threaded up through the opening 142 until the bead abuts the margin
of the opening. The wire extends straight upward in a run 158a
between the sides of the H-shaped spring 145 between the flanges of
the I-beam and is secured at the top of the I-beam as at 164. The
securement is not only mechanical but also electrical. The wire
then extends in a run 158b down between the flanges 152, 154 on the
other side of the medial web 150 and between the sides of the
H-shaped spring 145 and passes through the aperture 144 and the
base plate 140 and is there secured. It should be understood that
current does not flow through the return section of the wire 158b.
The return section is instead means to stabilize the beam and hold
it down.
The cover 114 of the wafer may be held on the wafer by the rivets
166.
The tail 162 of the wire 158 may double back through the bead 160
and opening 142 without contacting the base 140 and extend upward
and is electrically and mechanically secured to the upper cap 118
by being inserted into hole 118a provided in cap 118 and being
soldered in place.
FIGS. 17 through 19 diagrammatically indicate the operation of the
version of the slave switch disposed in the wafer 110. FIG. 17
shows the slave switch in the cold condition, that is, a condition
in which the bulb B has not been activated for a relatively long
period of time. It will be seen that the contact 130 is in
engagement with the contact 156 on the beam 148. When the master
switch M is thrown on, current passes from the center contact CS
through the upward stretch of the wire 158a, down through the beam
148 to the contact 156, through the screw 130 and to the bulb B
activating it at brightest intensity.
Subsequently, FIG. 18, the Nichrome wire 158 lengthens. This
permits the top of the beam to move leftwardly pivotally about the
inward end of the screw 130, the downward run of the wire 158a
remaining constant and supplying a downward force vector reflecting
the upward urging of H-shaped spring 145 which keeps both stretches
of the wire 158 taut. The lower end of the beam moves rightward on
spring 145.
Subsequently (FIG. 19), if the circuit is interrupted as by the
opening of the master switch, the upward run of the wire 158a
shortens causing the top of the beam 148 to move rightwardly
resulting in the clockwise pivoting of the beam 148 about its
engagement point with the spring 145. This causes the disengagement
of the contact 156 from the screw 130 causing current now to flow
to the lamp from the beam 148 through the H-shaped spring 145 to
the base plate 140 and through diode rectifier 146 if the master
switch is then closed within a present period. This causes half
power to flow to the filament of the bulb B resulting in a lighting
of the bulb. Because the average current drawn is less than with
the bulb on full, the power flowing through the upward stretch of
the wire 158a is sufficient to maintain the length of the wire
constant so that the arrangement diagrammatically shown in FIG. 19
holds as long as the current remains on and the bulb remains on
dim.
If, rather than closing the master switch in the interval in which
the contact 156 does not engage the screw 120, but the upward
stretch 158a of the wire 158 is permitted to cool further, said
stretch shortens causing the entire beam 148 to pivot about the
screw 134. As this happens, the lower end of the beam 148 slides
leftwardly (FIG. 19) along the arched spring 145 until the contact
156 engages the screw 130. This re-establishes the condition shown
in FIG. 17 wherein if the master switch is subsequently closed, the
bulb will come on, current passing the contact 156 to the screw 130
to short out the diode rectifier 146.
FIG. 20 demonstrates how the wafer with slave switch S disposed in
the lamp socket fits into the circuit to bring about a dimming
action when the master switch M is manipulated as described.
It will be understood that in the embodiment of FIGS. 13 through
21, dimming is achieved only by restoring within a preestablished
period the master switch to closed position after it has been
opened. The period may be, for instance, three seconds. Preferably,
this is achieved by flicking off and immediately on the master
switch M.
One of the features of the version of the slave switch disclosed in
FIGS. 13 through 21 is that it is temperature compensated. Should
the temperature of the environment change therefore, there will be
no adverse effect on the operation of the switch. This is because
the wire 158 extends on either side of the beam 148 and determines
its attitude. As the ambient rises, there will be equal elongation
on both stretches 158a and 158c, for instance, causing no change in
the disposition of the beam with respect to the base 140. The
spring 145 will compensate for the elongation of the stretches and
keep those wires taut by raising the beam. Conversely, upon cooling
of the environment, the stretches 158a and 158b, being of the same
material, will both contract together so that the attitude of the
beam 148 will not change. Spring 145 yields downward as necessary
during the contraction.
An interesting feature of the structures disclosed herein is that
the contacts 60, 86 and 130, 156 are closed and opened during the
period in which the master switch is off so that there is no arcing
problem connected with the making and breaking of the contacts.
It should be understood that herein the two versions of the slave
switch disclosed are illustrative just as their respective mounting
in the bulb and in the wafer are illustrative. Thus, the FIGS. 1-
12 version could be mounted in a wafer and the FIGS. 13- 21 version
could be in a bulb. The specific disclosures are illustrative not
only as different slave switches possible, but also as different
ways in which the switches may be employed in a lighting
system.
The word "word" herein and in the claims is intended to have a
broad meaning including any electric means by which light is
produced such as: a single incandescent electric bulb, an electric
bulb having a plurality of filaments, a plurality of incandescent
bulbs, and a plurality of fluorescent tubes.
It should thus be clear that the benefits of the above described
embodiments will flow from other embodiments not described and
hence the scope of the invention should not be limited by the
embodiments herein disclosed, but should be limited by the
following claim language and reasonable equivalents thereof:
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