Note: Descriptions are shown in the official language in which they were submitted.
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This application is a division of our Canadian patent application
Serial No. 264, 907 filed November 4, 1976.
Time controlled or electric clock thermostats have for many years
required at least three wires to connect the thermostat to a remote source of
power and a control apparatus for a system for controlling the supply of
temperature condition medium to the space wherein the thermostat is located.
In the modification of original construction in which two wires are required
for a simple thermostat, considerable difficulty is experienced when the
system is to be converted for use with a clock thermostat as extra wires are
pulled through the wall.
To overcome the necessity of pulling extra wires to power a clock
thermostat over the same two wires on which the control apparatus is control-
led, various expensive schemes have been provided such as in the United States
Clifford L. Nelson et al Patent 3,620,448, issued November 16, 1971, and the
United States Balthasar H. Pinckaers Patent 3,599,863, issued August 17, 1971,
wherein the clock motor is powered over the two wires and a signal of a dif-
ferent power factor or waveform is superimposed over the two wires for con-
trolling the remote control apparatus.
Obviously, with the advent of lower power, extremely accurate
battery driven time controlled units or clocks, such as the crystal oscilla-
tor type now available, the use of such a motor for powering an electric
clock thermostat has been proposed, however, because of the torque require-
ment that the motor must have to do the added work of directly moving a
mechanism which changes the temperature maintained in the space, power re-
quired from such a battery is large enough that frequent changing or recharg-
ing of the battery must be accomplished.
The present invention provides a rechargeable battery powered
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electric clock thermostat for use in a system for controlling remote control
apparatus over two wires and for connecting the battery through a charging
circuit over the same two wires to a remote power source; so that, an electric
clock thermostat can be used to replace a simple thermostat without the expense
of additional wires for providing a control circuit for the thermostat and an
energization circuit for the clock motor.
Thus, in accordance with a broad aspect of the invention, there
is provided a clock thermostat device for connection by two wires to a remote
unit comprising an alternating current power source and a control apparatus
responsive to A.C. current for operation of temperature conditioning appara-
tus, comprising:
thermostat means having selectable temperature control points and
having a thermostatic switch for operating at a selected control point, said
thermostat means responsive to ambient temperature for opening and closing
of said thermostatic switch when said ambient temperature varies a determined
amount from said selected control point, said switch for providing A.C. cur-
rent over the two wires to energize the control apparatus;
clock means for cyclically changing said selected control point
of said thermostatic means from an initial value to a second value at a first
time, and at a second time thereafter restoring said control point to said
initial value;
rechargeable battery means for providing energy for said clock
means independent of the two wires; and
rectifying means for connection to the two wires for providing
charging current to said battery means and providing a return current path
between the two wires for the positive cycle of said alternating current
power source and a return current path between the two wires for the negative
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cycle of said alternating current power source, whereby the control apparatus
receives a continuous A.C. current along the two wires.
- The embodiments of the present invention are shown in the follow-
ing figures of which
Figure 1 is a schematic showing of the connection of a battery
powered time controlled thermostat apparatus to a remote source of power and
control apparatus for controlling the supply of temperature condition medium
to the space in which the thermostat is mounted, and
Figure 2 is a first embodiment of the present invention, and
Figure 3 is another embodiment of the invention, and
Figure 4 is still another embodiment of the invention.
DESCRIPTION OF THE INVENTION
Referring ~o Figure 1, the temperature in a space 10 is controlled
by a temperature responsive device or thermostat apparatus 11 connected by two
wires 12 and 13 to a remote control panel 14. Panel 14 has a source of power
15 and an output circuit 20 connected to a control apparatus or valve 21 of a
system for controlling the supply of fuel or gas to a temperature conditioning
apparatus or furnace 22 for temperature conditioning or heating medium or air
being circulated through the space 10 through duct 23 by a fan 24.
Thermostat apparatus 11 has a temperature responsive control means
or mechanism for maintaining one of two different levels of temperature or
bimetal operated switch means 25, such as a clock thermostat disclosed in the
United States Carl. G Kronmiller Patent 2,558,617, issued June 26, 1951,
comprising a bimetal element which controls a switch to complete a circuit
to provide power to remote control apparatus 21. The temperature control of
the thermostat apparatus 11 is adjusted by a time controlled mechanism or
clock driven by a motor 30 to selectively adjust the control temperature
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maintained during different time periods to typically maintain a daytime
temperature of 72 and at 10:00 p.m. to change the control point of the ther-
mostat to maintain a nighttime temperature of 65 until morning when the day-
time temperature is again selected. Any one particular type of thermostat
apparatus 11 for selectively maintaining different controlled temperatures
in a space 10 is not required for use in the present invention. Motor 30 is
a rechargeable battery powered motor connected to a battery 32 which is re-
charged over the same two wires 12 and 13 by a charging circuit to be des-
cribed.
Referring to Figure 2, thermostat 11 is shown connected to panel
14 for controlling control apparatus or valve 21. Temperature responsive
switch 25 is adapted to connect the control circuit to the source of power
15 to energize valve 21. Circuit 31 is an adjustable circuit for energizing
conventional anticipation heater 26 thermally connected to temperature re-
sponsive switch means 25. The voltage to heater 26, can be adjusted by
selectively positioning input tap 27 to regulate the control of thermostat
switch 25. Motor 30 is connected to rechargeable battery 32 for driving
the time controlled mechanism of thermostat 11. One terminal of battery 32
is connected by conductor 33 to a diode 34 to wire 12 and the other terminal
of the battery is connected by conductor 35 through a limiting resistor 40
to the other wire 13 for providing a charging circuit to battery 32.
The battery is charged from source 15 all the time. By means of
a limiting resistor 40, the current drain from the source for the recharging
of the battery is limited below that required to operate valve 21. The valve
21 will not operate when the thermostat is not calling for heat.
The embodiment of the invention shown in Figure 3 comprises the
thermostat 11 connected over wires 12 and 13 to panel 14 with the source of
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power 15 and valve 21. The thermostat switch 25 is connected in parallel
with motor 30 so that when the switch is open current is supplied through
the diode 34 to recharge battery 32. A limiting resistor 40 is connected
to limit the current to prevent the operation of valve 21.
The embodiment of the invention as shown in Figure 4 has a ther-
mostat 11 connected over two wires 12 and 13 to a remote panel 14 having a
source of power 15 and a valve 21. Rectifying means 34 for supplying power
to recharge battery 32 comprises a conventional diode bridge for providing
a rectifying current during both cycles of the alternating current voltage
of source 15. The current drain from the source is limited by limiting re-
sistor 40.
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