Appliance paging system

A domestic appliance such as a clothes dryer having a signalling system including a portable radio receiver transportable by the appliance operator to locations remote from the operating cycle of said appliance to transmit a signal to said portable radio receiver to notify said operator that the operation of said appliance is completed. The system includes an adaptor for releasably and sealingly mounting the sensor unit within the flow exhaust air from the dryer, preferably with the sensing element covered by a screen. The adaptor has an inlet end attached to the exhaust fitment of the dryer and an outlet end attached to the outlet hose.

BACKGROUND OF THE INVENTION 
This invention relates to home appliances, such as washers, dryers, etc. 
and is particularly directed to paging systems for announcing to an 
operator that the appliance has completed operating a cycle. 
Washers and dryers have been considered to be standard home appliances for 
many years. More recently, it has become common for multiple housing 
complexes, such as apartment buildings, to provide several washers and 
dryers in a common laundry room which is available to all tenants of the 
complex. Similarly, laundromats contain a plurality of coin-operated 
washers and dryers which are available to the general public. These 
laundromats are frequently located in shopping centers or the like. 
DESCRIPTION OF THE PRIOR ART 
Many of the prior art washers and dryers have been provided with buzzers or 
lights to signal the operator when the appliance had completed its 
operation. Typical of the prior art systems are the U.S. patents to R. M. 
Sasnett, U.S. Pat. No. 3,050,864, issued Aug. 28, 1962; O. T. McIlvaine, 
U.S. Pat. No. 3,116,982, issued Jan. 7, 1964 and R. F. Doty, U.S. Pat. No. 
3,399,461, issued Sept. 3, 1968. Audible and visual signals are effective 
when the operator remains in the vicinity of the appliance during 
operation of the machine. However, when the appliances are located in a 
multiple user area, such as an apartment laundry room or a laundromat, it 
is more usual than not that users will place their clothing in a machine, 
start the machine on its operating cycle and then leave to go shopping or 
perform other activities while the machine is operating and will return at 
a later time to remove their clothes from the machine. Unfortunately, this 
usually means that the machine completes its operation before the operator 
returns from his other activities. When this occurs, the machine must sit 
idly until the operator returns, which means a lack of utility of the 
machine and loss of profit to a laundromat owner. Alternatively, another 
person wishing to use the machine will remove the original operator's 
clothing from the machine and leave it on a nearby talbe or shelf. 
However, when this is done, the person removing the clothing does not 
often use the same degree of care in removing the clothing that the owner 
of the clothes would use. Thus, when the owner of the clothes returns, he 
may find the clothes mussed or even dirtier than they were originally. 
Furthermore, it is not uncommon for someone to steal some or all of the 
clothing before the owner returns. 
Another important consideration in the operation of a dryer, whether in a 
multi-use facility or in a home or apartment, is the wasted energy 
expended in the operation of the appliance after the clothing has reached 
its optimum dryness. Even though most clothes dryers emit an audible 
signal on completion of a cycle, most clothes dryers are located in the 
garage or some remote place where you cannot hear the signal when the 
cycle is complete, or, when the machine shuts off. 
Very often a person wants to take advantage of a nap when laundering but 
does not for fear of not waking in time before the machine shuts off. If 
this happened, the clothes would wrinkle if left unattended for even one 
(1) minute. It is estimated that dryers run eight (8) minutes per load 
beyond the time that the clothes are dry and ready to be removed. This 
computes to an estimated cost savings of $75.00/yr for a family of four 
(4) based on the following calculations: 
GAS DRYER DATA 
Average gas dryer uses 175 THERMS/load. At today's cost rate, this equals 
$0.60/load. 
1 THERM=100,000 BTUs 
1,000 BTUs=1 cu.ft. of natural gas 
100 cu.ft.=1 THERM 
It takes 5.71 gas dryer loads to equal 1 THERM. 
Therefore: 
5.71 loads/wk=296.92 loads/yr 
296.92.times.0.175=51.96 THERMS/yr 
51.96 THERMS.times.100 cu.ft.=5196 cu.ft./yr 
Estimate 8 minutes/load savings=0.1333hr 
Average 30 minutes/load-0.5hr 
0.1333 hrs.=26.6%.times.51.96 THERMS=13.85 THERM saving=1385.59 cu.ft. of 
natural gas saved per year per dryer. 
If 10,000,000 families purchased this device, this computes to a savings of 
13,850,000,000 cu.ft. of natural gas per year. 
ELECTRIC DRYER DATA 
(Information based on Southern California Edison) 
An electric dryer rated at 4850 watts uses 7.9 kw per month doing 26 loads. 
7.9 kw.times.12 months=94.8 kw/yr. 
8 minute savings/load=26.6% (15 hrs/load). 
26.6%.times.7.9=2.10 kw.times.12 months 25.21 kw savings/yr. 
25.61 kw.times.10,000,000 users=252,100,000 kw hrs saved annually. 
Since electric capacity in the United States is supplemented by 
hydroelectric plants using natural gas or oil to develop steam to operate 
the turbine-generators, the savings in energy will conserve a domestic 
resource and reduce dependency on the import of oil from foreign sources. 
SUMMARY OF THE INVENTION 
These disadvantage of the prior art are overcome with the improved 
signalling means for appliances of the present invention which permit the 
appliance to notify the operator, even in a remote location, that the 
appliance has completed its operation. This enables the operator to return 
promptly to recover his clothing, quickly frees the machine for a 
subsequent user and minimizes use of energy. 
The advantages of the present invention are attained by providing an alarm 
system which senses completion of the operating cycle of an appliance and, 
in response thereto, transmits a signal to a portable receiver unit which 
can be carried by the operator of the appliance. 
The remote cordless receiver to monitor when clothes are dry is a very 
useful and beneficial item. It can be carried in a pocket, clipped on your 
side, or, just set at a convenient place where it can be heard. In a 
preferred embodiment of the paging system of the invention the humidity 
sensor is mounted in the exhaust duct or an adaptor attached to the 
exhaust outlet. The paging system can be packaged as an attachment kit 
that can be added to any clothes dryer. 
By use of the appliance paging system of the invention, the appliance and 
operator do not have to continually open and close the dryer door to check 
if clothes are dry. Allows freedom to tend to other duties, or nap, 
without being concerned that the dryer will shut off, and, as a result, 
clothes will wrinkle. One can set the timer and/or humidity sensor a 
maximum setting and depend on the signal to alert you when clothes are 
dry. The dryer will consume only enough electricity and natural gas 
necessary to dry the clothes. Delicate fabrics will not be exposed to 
"over" drying. The dryer motor and heating element will be utilized less 
therefore less maintenance/repair bills and will last longer. Considerable 
energy savings in natural gas and electricity are provided as would be 
reduction in air pollution related to less combustion of oil to produce 
the saved electricity. 
These and many other advantages and attendant features of the present 
invention will become apparent as the invention becomes better understood 
from the following detailed description when considered in conjunction 
with reference to the figures of the accompanying drawing.

DETAILED DESCRIPTION OF INVENTION 
A first embodiment of a dryer paging system is illustrated in FIGS. 1, 2, 
3. In this embodiment, the humidity sensor unit 100 is mounted external to 
the dryer 101. The unit 100 is mounted on an adaptor 103 which attaches to 
the hot air, outlet fitment 105 of the dryer 101. The adaptor 103 has an 
inlet end 107 and an outlet end 109. The inlet end 107 preferably includes 
slits, not shown, which allows the adaptor, suitably formed of metal, to 
fit over or under the outlet fitment 105. The inlet end 107 is then sealed 
and rigidly connected to the fitment by means of a ring or band circular 
clamp 113. The outlet end 109 of the adaptor 103 is connected to an 
exhaust hose 115 such as a corrugated, covered wire hose by means of a 
further clamp 117. The other end of the hose 115 is connected to the wall 
vent 119. 
The sensor unit 100 is mounted on the adaptor 103 in a manner to allow 
ready access to clean the sensor element 123. 
The sensor element 123 is disposed in a holder 124 mounted in an axial bore 
126 in the hub 140. A flat mounting plate 127, suitably formed of plastic, 
is attached to the central section 130 of the adaptor 103. A first 
circular groove 132 in the inside faces 133 of the plate 127 receives a 
cylindrical rim 134 formed on the central section 130 of the adaptor 103. 
A second circular groove 135 receives the inner edge 136 of a cup-shaped 
lint screen 137 which protects the sensor element 123 from the lint 
carried in the hot-air exhaust leaving the dryer 101. 
The plate has a central circular channel 138 connected to a plurality of 
tangentially positioned, equally spaced, radial slots 139. A hub 140 
containing a plurality of radial teeth 141 is attached to the inner face 
129 of the housing 125. When the housing 125 is twisted, the teeth 141 
lock in the mounting plate 127. 
The signal from the unit 101 is sent to the transmitting unit 150 by means 
of a wire 142. The transmitting unit can be powered by battery or from an 
external source of power such as standard AC power receptacle 144 by means 
of power cord 146. The transmitting unit 150 sends the signal indicative 
of the end point humidity of the air through an antenna 148. The signal is 
received through the antenna 154 of the hand-held receiver unit 152. 
A recommended humidity sensor is a duct mounted transmitter unit, Humicap 
HMP 122Y, which can be utilized in operation with a Humicap Relay Unit HMR 
120. This unit utilizes a capacitive thin film sensor giving excellent 
accuracy and reliability of humidity reading based on the capacitive 
change in a 1 micron thin polymer film as it absorbs water vapor. These 
sensors give accuracy of .+-.2% RH with excellent response time and 
long-term reliability. 
This after-market sensor unit can readily be added to existing dryers with 
standard tools and clamps. The unit is added to the dryer 101 by removing 
the clamp holding the existing exhaust hose 115. The inlet end 107 of the 
adaptor is slid over or into the outlet fitment 105 of the dryer 101 and 
the belt clamp 113 is installed. The hose 115 is then reattached to the 
outlet end 109 of the adaptor by means of a further clamp 117. The sensor 
unit 100 is placed over the aperture 138 in the plate 127 with the radial 
teeth 141 on the hub 140 facing the slots 139 in the mounting plate 127. 
The sensor unit is twisted to lock the unit in place. The screen 137 had 
been preinstalled in the inner groove 135 on the adaptor plate 127. 
A second embodiment of the present invention is shown in FIGS. 4-5. FIG. 4 
shows an automatic clothes dryer, indicated generally at 2, having a 
housing 4 with a door 6 and a control panel 8. Within the housing 4 are a 
rotatable drum 10, a heating unit 12, an exhast header 14, a motor 16 for 
driving the drum 10, an exhaust fan 18 and an exhaust duct 20. On the 
control panel 8 are a start button 22, a coin-actuated switch 24 and a 
generally rectangular container 26 having a lid 28 for releasably 
retaining a portable receiver 30. The container 26 is provided with a 
manually-engageable, solenoid-releasable lock 32 for retaining the lid 28 
in its closed position. A similar lock 34 is provided on the housing 4 and 
serves to retain the door 6 in its closed position. 
FIG. 5 is a diagrammatic representation of the system for energizing and 
controlling the dryer 2 of FIG. 4. As usual, the dryer 2 is energized 
across a three wire electrical system including supply conductors 36 and 
38 and a neutral conductor 40. Conventionally, a voltage of 220 volts is 
applied between the conductors 36 and 38 and a voltage of 110 volts is 
provided between the neutral conductor 40 and either of the supply 
conductors 36 and 38. Actuation of the entire control system is under the 
control of the coin-actuated switch 24. Obviously, if the present 
invention is intended for use in a home appliance, the coinactuated switch 
24 may be replaced by a simple manual switch. 
A timer motor 42 is connected between supply conductor 38 and the neutral 
conductor 40 and controls cams 44, 46 and 48, rotating the cams at a slow 
rate to control cam switches 50, 52, 54 so as to provide a full operating 
cycle for the dryer 2. However, switches 50, 52 and 54 are initially 
closed by operation of the coin-actuated switch 24. Cam switch 50 controls 
the operation of the heater 12 which is energized when switches 24 and 50 
are closed. Switch 52 controls the energization of timer motor 42. Neutral 
conductor 40 is connected to the junction of the run winding 56 and start 
winding 58 of motor 16. Preferably, motor 16 will be a low-impedence 
induction-type motor having the run winding 56 continuously in the circuit 
while the dryer 2 is operating. The start winding 58 is connected in the 
circuit only briefly, at the beginning of operation, to effect starting of 
the motor 16 and then, as the motor 16 comes up to speed, speed actuated 
switch 60 serves to deenergize the start winding 58 and motor 16 operates 
thereafter on the run winding 56 alone. 
The windings 56 and 58 of motor 16 are connected to supply conductor 38 
through conductor 62 and either a highimpedence device, such as radio 
transmitter 64, or a shunt circuit 66 which includes cam switch 54. 
Conductor 62 also includes solenoid 68 which, when actuated, serves to 
release lock 32 to permit removal of the portable radio receiver 30 from 
container 26. As noted above, the control system is energized by actuation 
of the coin-actuated switch 24. However, initiation of the actual 
operation is controlled by the manually-actuated start button 22. Finally, 
a humidity sensing device 70 is preferably mounted to sense the moisture 
content of the air in the exhaust duct 20 and serves, when the humidity 
falls below a predetermined value, to trigger the radio transmitter 64 and 
to shut off the heater 12. 
In use, an operator opens door 6, deposits the laundry to be dried in the 
drum 10 of the dryer 2 and closes door 6 which causes the 
manually-operated lock 34 to engage and prevents unauthorized removal of 
the clothing from the dryer 2. The operator then places the required coins 
in the coinactuated switch 24 and actuates the switch 24 to energize the 
control system. Then, the operator depresses start button 22 to initiate 
the operation. 
Actuation of the start button 22 energizes the windings 56 and 58 of motor 
16 and actuates solenoid 68 to release lock 32 and, hence, permit removal 
of the portable radio receiver 30 from the container 26 on the control 
panel 8 of the dryer 2. The dryer 2 will now proceed to dry the clothing, 
while the operator takes the portable radio receiver 30 and is free to 
leave the laundry area and to perform various other activities at remote 
locations. When the dryer 2 has completed its operation, the timer motor 
42 will cause cam 48 to open cam switch 54, breaking shunt circuit 66 and 
energizing radio transmitter 64 to send a message to the portable radio 
receiver 30, as indicated by arrows 72 in FIG. 2. It will be apparent to 
those skilled in the art that the signal from the radio transmitter 64 may 
be suitably coded so that its signal will only be detected by the 
corresponding portable radio receiver 30. Upon receipt of the signal from 
the radio transmitter 64, the portable radio receiver 30 provides an 
audible and/or visual signal to the operator to announce that the dryer 2 
has completed its operation. The operator may then return to the laundry 
area and, by pressing button 74 of the portable radio receiver 30, can 
send a signal to actuate solenoid switch 76 to release the lock 34 on door 
6 of the dryer 2. Until the operator presses button 74 to actuate the 
solenoid switch 76, the door 6 of the dryer 2 will remain locked, thereby 
preventing unauthorized removal of the operator's clothing from the dryer. 
As is well known, the time required to dry any given load of clothing will 
vary greatly depending upon the material of the clothing, the size of the 
load, etc. Obviously, the timing motor 42 can only determine the time 
required to perform an average drying operation. However, where small 
loads or fast-drying materials are involved, this may result in 
unnecessarily long drying periods. This is wasteful of the energy required 
to operate the dryer 2 and causes delays in freeing the dryer 2 for use by 
subsequent operators which is costly to the laundromat owner. These 
disadvantages are overcome by the inclusion of the humidity sensing device 
70. As noted above, the humidity sensing device 70 determines when the 
moisture content of the air in the exhaust duct 20 has fallen below a 
predetermined value and, when this occurs, the humidity sensing device 70 
acts to trigger the radio transmitter 64 and to shut off the heater 12 by 
opening switch 50. This prevents waste of energy by the heater 12 and 
notifies the operator that his clothing is ready. 
If desired, the signal button 74 may be omitted from the portable radio 
receiver 30 and switch 76 may be actuated by a manual switch operable, for 
example, by replacement of the portable radio receiver 30 within the 
container 26 and closure of the lid 28 of the container 26, thereby 
assuring return of the portable radio receiver 30 by the operator. Should 
the operator delay returning for his clothing within a predetermined 
period, additional coins would be required to actuate the door lock 34. 
Furthermore, it will be apparent that the present invention would be 
equally applicable to washing machines and other appliances. 
It is to be understood that numerous other variations and modifications can 
obviously be made without departing from the present invention. Therefore, 
it should be clearly understood that the form of the present invention 
described above and shown in the accompanying drawings is illustrative 
only and is not intended to limit the scope of the present invention.