Note: Descriptions are shown in the official language in which they were submitted.
This invention relates to a light dimmer switch and,
; more particularly~ to a three-way light dimmer switch
combination utilizing independent light dimmer circuits for
controlling the brightness of a lamp.
BRIEF DESCRIPTION OF THE PRIOR ART
Many different types of circuits have been designed in
the past for controlling the brightness of lamps or lighting
systems. Initially, variable resistors were used with a
portion of the voltage applied to the liyhting system being
dissipated in the resistor to reduce the illumination from
the lights. Power not dissipated in the lights was dissipated
in the variable resistor as the illumination of the lighting
~` system changed. While this means of dimming was feasible
lS when the cost of energy was less~ the variable resistance
:~ dimming networks are no longer feasible because of today's
high cost of energy.
As solid state electronics developed, many different
; types of switching arrangements were devised to provide
dimming capabilities in various lighting systems. Initially,
transistor switching devices were used. The transistors
would conduct only during a portion OI the cycle depending upon
; the base voltage applied to the transistor. As the length o~
time the base voltage was above the amount necessary for
conduction of the transistor was varied, the period of
conduction of the transistor was also varied.
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With the further development of silicon control rec-tifiers
(SCR), the conduction time through the SCR could be varied by
varying the voltage applied to the gate. This woUltl allow the
lamp or other lighting system to conduct for a portion of a half-
cycle, or a portion o:E the full cycle, if the AC vol-tage was
fully rectified. Conduction would depend upon the gate voltage
applied to the silicon control rectifier. Wi-th the further
development of thyristors (silicon control rectifiers and triacs
being a type of thyristors), a triac will conduct during either
half-cycle of standard AC line voltage depending upon the gate
voltage applied to the triac. Diacs have been in common use for
triggering the conduction of triacs as can be seen in SCR Manual,
5th Edition, 1972, General Electric Company, page 192.
Even with the tremendous advances in liyht dimming circuits
to allow the dimming of lamps without excessive power waste, none
of the prior art shows a three-way light dimming switch combin-
ation with independent dimmer circuits located in either switch
and with either switch having light dimming capabilities. For
example, Hunt Electronics Company has done considerable work
with light dimming systems, but even in their issued patents
(U.S. Patent No. 3,846,671 to Johnson and U.S. Patent No.
3,868,546 to Gilbreath) only a single light dimming circuit was
used with remote controls -for two independent switches control-
ling the single light dimming circuit.
Skirpan (U.5. Patent No. 3,534,224) shows a fairly
complex electronic apparatus that has two separate light
dimming circuits with their respective loads being controlled
by one supervisory control. The purpose of Skirpan was to
provide for simultaneous increase in brightness of one load
and decrease in brightness of another load. A typical example
of the proposed use of Skirpan was to decrease the intensity
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of theater lights while simultaneously increasing the inten~ity
of the stage lights, or vice versa.
Another alternative dimming circuit is shown in Woodnutt
(U.S. Patent No. 3,~93,002) wherein the brightness oE the
lighting system depends upon the charge of an RC circuit that
has a very long time constant.
SUMMARY OF THE INVENTION
.
It is an object of the present invention to provide a
three-way light dimmer switch.
It is still another object of the present invention to
provide a first light dimmer switch that can be combined
with a second light dimmer switch to give three-way light
dimming capabilities. Each of the light dimmer switches has
a common lead connecting to a contactor arm. As a vertically
actuated lever arm of either of the switches is moved from
one limit of its vertical position, a contact is broken;
and as the vertically actuated lever arm moves to the opposite
limit of its vertical movement, another contact is broken.
Interconnected between contacts for the contactor arm is a
dimmer circuit for controlling the brightness of the lamp or
lighting system. By proper connection of the contacts for the
contactor arms for two llght dimmer switches, and by using
the common lead which connects to the actuator arm as the
input and output, the intensity of a lamp or other lighting
system can be varied from either light dimmer switch. By
proper interconnection between the two light dimmer switches,
either of the following capabilities may be provided.
(1) When either light dimmer switch is in the OFF position,
the opposite light dimmer switch will brighten, dim or turn
the lamp full ON; and when either light dimmer switch is
in the DIM or FULL position, the opposite light dimmer switch
will turn the lamp ON and OFF. (2) When either light dimmer
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switch is in the FULL position, the opposite light dimmèr
switch will brighten, dim or turn OFF the lamp; and when
either light dimmer switch is in the DIM or OFF position,
the opposite light dimmer switch will turn the lamp ON and
OFF.
BRIEF DESCR PTION OF THE DRAWINGS
Fig. 1 is a pictorial schematic diagram showing in-ternal
connection of three-way light dimmer switches for three-way
light dimming capability.
Fig. 2 is a detail schematic diagram of a three-way ligh-t
dimming switch.
Fig. 3 is a pictorial representation of each three-way
light dimming switch as interconnected to household wiring.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to Fig. 1 of the drawings, there is shown an
illustrative schematic diagram of a three-way connection between
vertically actuated light dimmer switches 10 and 12 for giving
three-way light dimming capability to lamp 14. Input line if
~or standard AC voltage is connected to contactor arm 18 of
light dimmer switch 10. In the position as shown, the vertically
actuated lever arm 20 which operates about pivot 21 has depressed
one end of the actuator arm into electrical contact with normally
opened (NO) contact 22. The opposite end of the contactor arm 18
is in electrical contact with normally closed (NC) contact 24.
~oth the NO contact 22 and the NC contact 24 are electrically
connected to dimmer circuit 26. If the vertically actuated
lever arm 20 is moved to the OFF position às illus-trated in
dotted lines, one end of the contactor arm 18 will break its
electrical connection with NO contact 22, and the opposite
end of the contactor arm 18 will break its electrical connection
with NC contact 24 and make an electrical connection with NO
contact 28.
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Referring to light dimmer switch 12, when the vertlcally
actuated lever arm 30 has pivoted about pivot point 32 to the
position as shown, contactor arm 34 will be depressed on one
end thereby making an electrical connection with NO contact 36.
Upon moving the lever arm 30 to the full ON position as repres- -
ented in dotted lines, one end of the contactor arm 34 will be
released thereby breaking the electrical.connection with NO con-
tact 36 and making an electrical connection with NC contact 38.
Simultaneously the opposite end of the contactor arm 34 will make
an electrical connection with NO contact 40. soth the NC contact
38 and the NO contact 40 connect to the dimmer circuit 42. ; ~:
Interconnection between the two light dimmer switches 10 `~
and 12 is provided by wires 44 and 46. One end of wire 44
connects to NO contact 28 of switch 10, and the opposite end of
wire 44 connects to NO contact 36 of switch 12. One end of wire
46 connects to NO contact 22 of switch 10~ and the opposite end
of wire 46 connects to NO contact 40 of switch 12. Light dimmer
switch 12 is connected to lamp 14 by means of wire 48 connected .:~
to contactor arm 34. Thereafter, lamp 14 is connected to the AC
input voltage via wire 50.
- Referring now to Fig. 3, the interconnection between light
dimmer switches 10 and 12 is illustrated pi.ctorially. Wires 44
and 46 connect between the switches 10 and 12. Wire 16 connects
to the AC input ~oltage and wire 48 connects to the lamp 14.
Referring now to Fig. 2 of the drawings, there is shown
a detail schematic diagram for either light dirnmer switch 10
or 12. For the purposes of illustration only, light dimmer
switch 10 has been selected for detail schematic representation
in Fig. 2. Like numerals as previouslv used will be used in
conjunction with the description of Fig. 2. The actua-tor arrn
20 is in the DIM position thereby allowing current flow through
dimmer circuit 26. It should be realized that the actuator
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arm 20 as functlonally shown in Fig. 2 is nonconductive.
Also, wire 50 for the second AC input lead is not shown in Fig. 2
The AC input voltage is fed through contactor arm 18 and
NO contact 24 to variable resistor 52, triac 5~ and capacitor 56.
The triac 54 is connected in series with inductor 58, which
connects through switch 12 to the AC input voltage. The charge
on capacitor 56 approximately follows the AC inpu-t voltage.
As the lever arm 20 is varied between the FULL position
and the OFF position, the position of the wiper arm 60 of
variable resistor 52 is also varied. As the position of the
wiper arm 60 varies toward the FULL position of the lever arm 20,
charge on capacitor 62 is increased. As the charge on capacitor
62 increases, the voltage across diac 64 also increases. When
the limit voltage, either positive or negative, of diac 64
is exceeded, diac 64 will trigger conduction of triac 54. By
controlling the trigger point of diac 64 with variable
resistor 52, the conduction of triac 54 can also be controlled.
The RC circuit formed by resistor 66 and capacitor 68 provides
a phase shift and a time delay in the triggering of diac 64.
By movement of lever arm 20 to its uppermost position
as shown in Fig. 2, contactor arm 18 will break its electrical
connection with NO contact 24 and make an electrical connection
with NO contact 28 which will thereby remove dimmer circuit
26 from the three-way circuit as explained in conjunction with
Fig. 1. Such a position for lever arm 20 has been designated
the OFF position. By moving the lever arm 20 to its lowermost
position as shown in Fig. 2, contactor arm 18 will make an
electrical connection with NO contact 22 thereby shorting out
or bypassing the dimmer circuit 26. Such a position for the
lever arm 20 has been designated the FULL position.
- As a preferred embodiment, assuming that switch 12 is
in the OFF position as shown in Fig. 1, then light dimmer
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switch 10 may either dim lamp 14 or turn lamp 14 to the FULLposition by contactor arm 18 making an electrical connection
with NO con-tact 22. Likewise, swi-tch 10 may turn OFF the
lamp 14 by the lever arm 20 moving contactor arm 18 to
break the electrical connection with NC contact 24 and make
an electrical connection with NO contact 28.
As an alternative embodimentr if light dimmer switch 12
is in the FULL position as shown in dotted lines in Fig. 1,
again, switch 10 may either turn lamp 14 ON or OFF, or dim
lamp 14. However, if switch 12 is in the DIM position~ then
switch 10 must be in either the OFF or FULL position for lamp 14
to illuminate at the particular brightness set by dimmer : .
circuit 42.
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