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BACKGROUND OF THE INVENTION
Arrangements permitting local and remote control of switches are well
known. Typically, remote control is achieved by the use of signals
produced by radio, light or audio sources. Additionally, such control is
obtained by timer means.
Such arrangements as just outlined also have been employed to control wall
switches. Examples of prior art of this type are U.S. Pat. No. 3,558,902,
issued to Everett R. Casey on Jan. 26, 1971, and U.S. Pat. No. 3,740,680,
which granted to Carl Schneidinger on June 19, 1973. The former discloses
a wiring system employing a receiver mechanism contained within a wall box
which receives a switch. The receivers are responsive to radio frequency
signal transmitted over the electrical wiring of the building. U.S. Pat.
No. 3,740,680 is concerned with a timer which is associated with a wall
switch for operating same at desired times.
SUMMARY OF THE INVENTION
The present invention is intended to provide safety, security and
convenience for the user. This is accomplished by the provision of remote
operation of a wall switch allowing operation of switches at any building
location from a remote point. This is accomplished without disabling the
capability of manual operation of the switches and without substantially
altering their outward appearance.
Of course, the invention also provides energy conservation through
automatic de-activation of circuits not required.
A first automatic function according to the present invention is remote
control of switch operation accomplished by a sub-miniature receiver
commanded from a digital controller. The receiver responds to coded
information from the digital controller, performs de-coding thereof, and
provides a control function to drive a switch actuator (or other circuits
to be described hereinafter). Thus, a remote signal is used to turn the
switch on or off, as desired. The digital controller and receiver system
generate and receive coded signals over the same wiring as is used for the
building power. The receiver, actuator and switch are incorporated into an
integral unit cooperating to perform automatic control of the switch.
A second automatic function is obtained through the use of the same switch
and actuator mechanism as just described, but which is controlled by an
integral timer. An example of this local type of automatic operation is as
follows: the switch is turned "on" manually an a time delay interval is
selected. When the user activates a start control, the electric lamp or
other device remains on until the user has had an opportunity to pass to
an area of safety, at which time the switch deactivates automatically.
This type of operation prevents an unsafe act of groping through a
darkened area, and saves electrical energy that otherwise would be
expended if the light were left on.
The switch is designed to incorporate remote or local automatic control
functions, or both, while retaining its manual operation capability. This
permits the user to select the switch control best suited for his
requirements.
DETAILS OF THE INVENTION
The invention now will be described in greater detail with reference to the
accompanying drawings wherein:
FIG. 1 is an isometric and partially cut away view of a preferred
embodiment of the invention showing two solenoid coils with a common
armature driving the switch toggle lever through a coupling arm;
FIG. 2 is a partial block and partial schematic diagram of the automatic
switch shown in FIG. 1;
FIG. 3 is a schematic diagram of a receiver and power supply used in the
preferred embodiment of the invention;
FIG. 4 is a schematic diagram of a timer used in the preferred embodiment
of this invention;
FIG. 5 is a schematic diagram of a relay driver used in the preferred
embodiment of the invention;
FIG. 6 is an isometric view of an alternative embodiment of the invention
employing a solid state switch to perform similar functions to those of
the preferred embodiment;
FIG. 7 is a partial block and partial schematic diagram of the solid state
switch shown in FIG. 6; and
FIG. 8 is a schematic diagram of the solid state switch module forming a
portion of the switch shown in FIG. 7.
Referring to FIGS. 1-5, the preferred embodiment of the invention will be
described.
Initially, it should be noted that the automatic wall switch described
hereinafter mounts into conventional, existing wall switch boxes.
Consequently, its outward appearance is similar to a common toggle wall
switch except for the addition of a small control knob 21 and push button
20 which is evident on face plate 22.
Switch body 11 contains the following: a control electronics package 15
(decribed later), solenoid coils 12 and 14, and solenoid armature 18
connected to toggle shaft 13 through coupling arm 19. Power switch 8 (FIG.
2) is operated each time the toggle lever 10 is actuated, whether
automatically or manually. Switch body 11 has three electrical terminals.
In FIG. 2, it can be seen that the 115 volt line 26 enters on terminal 53.
It then goes to power switch 8 and exits on terminal 55 to line 28 which
continues to the device, such as a lamp, which is being controlled.
Internally, from terminal 53, the 115 volt line goes to a D.C. power
supply 78. An A.C. ground line 30 is tapped and brought in on terminal 51
and taken to D.C. power supply 78. Thus, the electronics contained in
switch body 11 derives its power from the line. D.C. power is taken from
supply 78 (shown in detail in FIG. 3) to the receiver 16, timer 17, OR
gates 71 and 75, and to relay drivers 72 and 76.
Manual operation of the switch is considered understood by all in that
movement of toggle lever 10 actuates electric power switch 8, through
shaft 13. The electrical contact detail of switch 8 is not shown, as this
is a well practiced art in many forms, including mercury switches.
When toggle switch 10 is moved, the motion is transferred via coupling arm
19 to common solenoid armature 18. Conversely, when either solenoid coil
is energized, magnetic force pulls the armature 18 into the respective
energized coil 12 or 14. This motion is transferred through coupling arm
19 to toggle lever 10 via shaft 19, thereby operating the switch.
Automatic operation of the switch will be described intially from a
functional standpoint. Such operation of the switch is provided by
internal receiver 16, or timer 17, contained in electronics package 15,
both of which provide two outputs. Lines 5 and 6 are connected in a manner
to turn the power switch 8 ON and lines 3 and 4 are employed to turn the
switch OFF. The receiver 16 (shown in detail in FIG. 3) receives its
command signals over the power line when terminals 61 and 62 are
connected. The timer 17 (shown in FIG. 4) divides the power line frequency
to provide signals that turn the switch ON or OFF in accordance with a
delay interval selectable with timer set knob 21. Either sequence of
operation begins when push botton 20 is actuated. An OR circuit 75
receives ON signals from receiver 16 on line 6 and from timer 17 on line
5. When either signal is present at an input to OR circuit 75, an output
is produced to turn on relay driver 76. The same functions apply with OR
circuit 71 and relay driver 72 to produce an OFF switch condition. Relay
drivers 72 and 76 provide the energizing current for solenoid coils 13 and
14, respectively.
In remote operation of the switch by digital signals transmitted over the
power line to receiver 16, the receiver recognizes only unique coded ON or
OFF commands from a remote digital controller that has injected these
signals into the building power wiring. Thus, the user can command the
switch at any time to turn ON or OFF by selecting and sending a particular
code for any given switch. All remote controlled switches in one building
may be coded alike, if desired, to permit all lights to be operated
simultaneously or each switch may have a separate code for independent
operation.
The internal timer 17 permits the user to select a delay time interval
after which the switch will automatically operate. An example of this
sequence is to assume the wall switch is ON, and the user selects a
5-minute delay interval with knob 21. When he pushes button 20, the timing
sequence begins and 5 minutes later, the wall switch turns OFF. The
opposite sequence occurs when the wall switch is initially OFF and the
user actuates start button 20, the wall switch turns ON after a 5-minute
delay interval. Time intervals mentioned in this disclosure are by no
means limiting, for as will be seen, a frequency divider chain can be
designed to provide a large number of discrete steps of delay, from
seconds to hours. The timer used may be of any circuit design that can be
fitted into the switch body.
Referring now primarily to FIG. 3, details of the receiver 16 will be
described. It will be assumed that an eight bit binary digital code has
been impressed on the building wiring. The receiver circuitry will decode
only the proper code and will provide an output for either turning the
wall switch ON or OFF.
The binary digital code is received on 115 V. A.C. line 26 and passes
through terminal 53 and jumper connection 61. The low frequency carrier
(60 Hz) is largely filtered by capacitors 311 and 312 along with resistors
313 and 314. These are chosen to form a high pass filter at the frequency
of the code transmission, e.g., 10 KHz or higher, and to highly attenuate
the 60 Hz line voltage carrier. A clock 305 is synchronized with the
digital controller at the 60 Hz line frequency.
The coded signals are connected to two 8 bit serial to parallel converters,
301 and 306, each of which is a type of shift register controlled by clock
305. Assuming an ON command signal is received, clock 305 transfers the
code into successive stages of shift register 306 until the first bit
arrives at the last stage of the register. At this time, all eight bits
are in the register. A dual output is provided at each stage, one inverted
and one normal, which outputs are called Q and Q. When the Q output is a
logic 1, or high, the Q is a logic 0, or low, and vice versa. Thus, it is
feasible to connect the Q and Q in outputs of the register stages in an
arrangement that corresponds to the digital code received so as to obtain
all 1's, or highs. These are fed in parallel to AND gate 307 which
produces a logic 1, or high output. This output is connected to OR gate
308. The output of OR gate 308 is assumed to be initially at logic 0, or
low, when the input signal arrives from AND gate 307. When gate 308 then
responds to the logic 1 output of gate 307, it produces a logic 1, or
high, which is connected to a one shot multivibrator 309. The one shot
circuit 309 produces a discrete pulse, logic 1, which is then fed to OR
circuit 75 (FIG. 2). As described above with respect to FIG. 2, the output
of circuit 75 is directed to relay driver 76 so as to momentarily energize
relay coil 14. This action pulls armature 18 into relay coil 14, thereby
moving switch 8 to the ON position. At this time, terminal 55 and line 28
are energized and the light or device being operated by switch 8 is turned
on. A line 7, joined to the switched A.C. line near terminal 55 (FIG. 2)
is connected to a rectifier circuit 310 in the receiver (FIG. 3) which,
with resistors 326, 327 and zener diode 328, are associated to develop a
logic 1, or high, when the power switch is ON. This logic 1 is coupled to
OR circuit 308 and inverter amplifier 315. As a result, the OR circuit 308
produces a constant logic 1 or high, as long as power switch 8 is on,
thereby preventing any additional signal which may arrive at the receiver
from producing a transition signal to turn on one shot circuit 309. This
means that the switch 8 can be turned OFF remotely only by the appropriate
receiver circuitry comprising 301, 302, 304 and 315.
The OFF circuitry operates the same way as described previously with
respect to the ON operation except as the OFF circuitry is controlled by
the connections between the 8 bit serial to parallel converter 301 and the
8 input AND gate 302 as well as the influence created by inverter
amplifier 315 which is used to insure that OR gate 303 remains locked up
once it is energized, thereby inhibiting further OFF signals. When switch
8 is off, there is no signal produced by rectifier 310, and thus no signal
at the input of 315. This condition automatically produces a logic 1, or
high output, which keeps OR gate 303 on continuously, preventing any
signal transition that would operate a one shot multivibrator 304 which is
joined via OR circuit 71 (FIG. 2) to control the energization of relay
coil 12.
Capacitor 316 is used to connect the A.C. ground to receiver ground for the
purpose of providing control signals. The ground symbol shown on the
diagram refers to D.C. ground within the receiver and power supply
circuits.
The 8 bit serial to parallel converters 301 and 306 are chosen to provide
high immunity from false codes, or from transients on the line. The use of
such converters also provides over 250 combinations of codes which allows
unique remote switching of circuits within large buildings. While two
converters are shown in FIG. 3 for the sake of clarity, it is apparent
that in practice, only one is required. Furthermore, other logic elements
may be used for a digital receiver, the present embodiment being but one
example thereof.
The power supply 78, shown with the receiver in FIG. 3, includes a common
diode bridge rectifier circuit 325 with filter capacitors 322 and 323 and
resistor 324 making up a D.C. filter circuit. Regulator circuit 320 is
used to control the D.C. output voltage for all the control circuits
within the switch body. The symbol used for the output of power supply 78
is the conventional term Vcc, used throughout these descriptions.
A schematic diagram of the electronic timer used in the automatic switch is
presented in FIG. 4. Timing is achieved by division of the power line
frequency to provide either ON and OFF delay periods.
As can be seen in FIG. 3, A.C. power from line 26 is brought to terminal 53
and passed through jumper 61 to the timer 17. Also, A.C. ground is
provided for the timer from the same terminal as shown in the receiver
schematic, terminal 64, and Vcc is supplied from power supply 78 and
terminal 63.
Referring now to FIG. 4, it can be seen that the input on the 60 Hz A.C.
line to the timer is rectified by diode 411, thereby developing a half
cycle pulse which is attenuated by resistor 412 and clamped to 4 volts by
zener diode 413. This 4 volt, 60 Hz pulse is fed to NOR gate 401 before
reaching the frequency divider chain made up of divider circuits 418
through 422. NOR gate 401 provides an output only when both input lines
are at logic 0, or low. During a timing interval, the reset line is logic
0, or low, and the input signal is also logic 0, or low during one half
cycle. Thus, gate 401 will produce one output pulse per cycle. When the
timer has completed its timing interval, a logic 1, or high, is fed back
to gate 401 on the reset line, locking it and preventing additional count
information from passing to the divider chain until reset button 20 is
manually actuated.
The 60 Hz pulses from gate 401 are first fed to divider 418. This is shown
as a divide by 60 device on the schematic. However, in practice it is made
up of two dividers cascaded to obtain the same result. Divider 418
provides one output pulse every 60 seconds which can be selected by
appropriate setting of timer set knob 21 and switch 410 to which knob 21
is joined. As shown in FIG. 4, the next divider step, which is 5 minutes,
has been selected by switch 410. Divider 419 divides the 60 second pulse
by five and produces one pulse every five minutes. Switch 410 directs this
pulse to three gates, OR gates 406 and 407, and NOR gate 403. Assuming
that reset switch 20 has been actuated, gate 401 has allowed pulses to
reach the divider chain, and divider 410 has just reached the end of its 5
minute interval, divider 419 will produce a logic 1, or high output. This
output first resets NOR gates 402 and 403 which have been in a logic 0, or
low output state, to a logic 1, or high state, resetting the counter chain
to zero and locking NOR gate 401, preventing further counting. Now
assuming further that toggle switch 10 was ON, and the intent was to turn
the switch OFF after the selected timing interval, the following takes
place. With the power switch ON, a logic 1, or high is produced by A.C.
voltage being fed to diode 414, resistor 415 and zener diode 416, and
being filtered by capacitor 417. This logic 1 condition at NOR gate 404
input produces a logic 0, or low output from gate 404 which is applied to
OR gate 406 which, along with a logic 1, or high, from switch 410 on the
other input to gate 406, produces a logic 1, or high output which is
coupled to a one shot multivibrator 409. The one shot 409 produces a
discrete pulse, a logic 1, or high, on line 3 coupled to OR gate 71 (FIG.
2). As a result, OR gate 71 produces a logic 1, or high, which turns on
relay driver 72 producing a pulse of current in solenoid coil 12, thereby
turning the switch OFF.
Since the same timing interval pulse is directed to both the ON and OFF OR
gates, 406, 407, respectively, a means of selecting which one is to
automatically operate has to be provided. This is accomplished by the A.C.
supplied from power switch 8, via line 7, to control gate 404 and to
provide the sense for operating the correct gate 406 or 407. In the
discussion of the preceding paragraph in which the toggle switch 10 was
ON, a means of opening gate 406 was described. Likewise, a means of
insuring that OR gate 407 is closed under such circumstances also is
necessary. This is accomplished by NOR gate 405 which produces a constant
logic 1, or high, when toggle switch 10 is ON, since NOR gate 404 has been
set thereby at a logic 1, or low output. When NOR gate 405 is held at a
logic 1, or high output, OR gate 407 is also held at a logic 1, or high
output, and therefore is unable to produce a pulse transition to operate a
one slot multivibrator 408. Thus the A.C. fed from power switch 8
automatically determines whether the timer turns ON or OFF after the user
operates starts switch 20.
The user may restart the timing sequence at any time by pressing start
switch 20, even though the timing sequence is well under way.
The automatic turn ON sequence is largely a duplication of the turn OFF
sequence just discussed. It is apparent from the preceding discussion how
gates 404, 405 and 407 produce an ON condition when power switch 8 is OFF.
When this occurs, the logic 1, or high, from one shot 408 is fed to line 5
and to OR gate 75 (FIG. 2) thereby energizing relay driver 76 and relay 14
to produce an ON condition at the end of the timing sequence.
As in the case of FIG. 3, all gates, dividers and one shots shown in FIG. 4
are connected to Vcc and ground to obtain power for their operation.
Referring to FIG. 5, the relay driver 72 (or 76) of FIG. 2 is shown in
detail. The relay driver is an NPN transistor 501 with relay coil 12 (or
14) located in the collector circuit. Diode 502 clamps the back EMF which
occurs when the coil is de-energized, thereby preventing breakdown of the
transistor. Resistor 503 limits the current that transistor 501 draws and
resistor 504 is used to hold the transistor base at ground potential in
the absence of a signal. A momentary logic 1, or high pulse from OR gate
71 (or 75) turns the transistor on to provide current to energize the coil
and actuate the switch 10.
An alternate embodiment of the invention, which accomplishes automatic
power switch operation with solid state devices, is illustrated in FIGS.
6-8. The operation of this switch is very similar to that described with
respect to FIGS. 1-5.
In FIG. 6, switch face plate 22 covers switch body 11, which contains an
electronic package 31. This version of the automatic wall switch uses
touch switches for manual operation, an ON switch 32 and an OFF switch 33.
Time delay is set by control knob 21, and the timer is started by
momentarily touching start button 20.
Automatic operation of the switch is the same as previously described for
the embodiment of FIGS. 1-5 as to the receiver, timer, power supply and OR
gates 71 and 75. The principal difference resides in the switch control
package 77 (FIG. 7) the details of which are shown in FIG. 8.
Referring to FIG. 8, touch switches 32 and 33 do not directly control the
electrical output, but rather supply logic signals which control a solid
state electrical switch 76. This diagram shows electrical switch contacts
associated with switches 32 and 33. However, other forms of touch switches
may be used to supply logic signals directly to the circuits shown.
The solid state switch 76 includes a Triac, labeled "T", which, along with
the Diac "D", switch the A.C. line when commanded. The switching control
for the Triac is a photocell and light source contained in package 613.
When the light is on, the photocell resistance greatly decreases, allowing
the Diac to trigger the Triac, thereby passing A.C. to the receiver 16 and
timer 17. As in the case of the embodiment of FIGS. 1-5, the receiver and
timer provide control signals for OR gates 71 and 75, and the function of
the gates is the same as previously described. This is representative
circuitry only, as many types of control are known for operation of solid
state power switching circuits.
Again referring to FIG. 8, OR gate 607 is the control for an automatic or a
manual OFF signal, while OR gate 608 performs the ON control function.
When either gate 607 or gate 608 provides a signal to its associated NOR
gate 609 or 610, respectively, the latter gates latch with one gate output
at logic 1 and the other having a logic 0 output. The state of these gates
depends on which signal is received last. Assuming the switch 33 is OFF,
the output of 609 is a logic 0, and the light 613 is not energized. This
condition exists when gate 609 has one input at logic 1, and the other at
logic 0, meaning that gate 610 output is at logic 1, or high. When the
manual switch 32 is pressed ON, a signal to a one shot multivibrator 606
is produced as capacitor 604 charges. Resistors 603 and 612 insure that
capacitor 604 is discharged when the switch is in the opposite position.
When one shot 606 fires, it produces a logic 1 signal to OR gate 608 which
passes it to NOR gate 610. Since NOR gate 610 now has two logic 1's on its
input, the output of gate 610 goes to logic 0. With two logic 0's on the
input of NOR gate 609, it produces a logic 1 output and latches in this
mode. The light in 613 is thereby energized and the Triac is switched on,
as previously described. The opposite sequence takes place when an OFF
signal is supplied from the receiver, timer or manual switch 33.
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