An improved icemaker having a number of features, including: a dual-activated feeler bar switch which combines the motion of two cams to operate a single switch; an adjustable-duration water fill switch which is closed by rotating a connector between two contacts; switches mounted to make wiping contact so as to clean the contact area; a combination deflector which not only deflects ice removed by the ejector from the ice mold, but also supports and lifts a feeler bar to determine whether the ice storage bin is full; a clutch mounted between the motor and ejector bar to permit slip therebetween so as to avoid stalling the motor as the ejector bar presses upon ice in the mold; a manual start button for starting the motor, simplifying installation; and an anti-back mechanism in the icemaker drive train to prevent an installer from damaging the icemaker by rotating it backwards.

FIELD OF THE INVENTION 
The present invention relates to domestic icemakers. 
BACKGROUND OF THE INVENTION 
A typical icemaker mounted in the freezer compartment of a domestic 
refrigerator will make about one harvest of cubes per hour. The typical 
icemaker includes a timing motor, a valve for admitting water into the ice 
mold to form ice, a thermostatic switch in thermal communication with the 
ice mold, a heater for partially melting the ice so that it will release 
from the mold, and an ejector bar with fingers for ejecting cubes from the 
mold. 
A typical harvest cycle begins with the timing motor running. During a 
water fill period defined by the motion of the timing motor, a 
predetermined quantity of water flows into the mold. After the mold is 
filled to the desired level, the timing motor shuts off, initiating a 
freezing period. The ice freezing period ends when the thermostatic switch 
changes state, indicating that the water has frozen to ice. The 
thermostatic switch turns the timing motor on. The motion of the timing 
motor turns the heater on and rotates the ejector bar until the fingers 
contact the ice. The timing motor then stalls in this position, the stall 
torque of the motor putting continued pressure on the ice in the mold. As 
soon as the heater has sufficiently melted the ice to release it from the 
mold, the fingers begin moving and eject the ice from the mold and into 
the storage bin. 
Once ice has been ejected into the bin, a feeler mechanism associated with 
the bin generates a signal to initiate a new cycle and form more ice if 
the bin is not full. 
Despite numerous prior units, there are certain difficulties with known 
icemakers. In particular, known icemakers have complex designs with a 
multiplicity of parts, particularly in the switching elements, increasing 
cost and reducing reliability. Furthermore, known icemakers require the 
use of stallable motors which are more expensive than non-stallable 
motors. Also, to perform an installation test of an existing icemaker, an 
installer must manually advance the switch timing mechanisms, which can 
require uncomfortable and difficult manipulation and increases the 
likelihood of damage to the icemaker during installation. 
Thus, it is an object of the invention to provide a simplified icemaker 
with fewer parts and greater reliability, particularly in the switching 
mechanisms. 
Further, it is an object of the invention to provide an icemaker in which 
the need for a stallable timing motor is eliminated. 
Further, it is an object of the invention to provide an icemaker having an 
improved installation testing procedure. 
SUMMARY OF THE INVENTION 
In accordance with one aspect of the invention, there is provided an 
icemaker timer having a dual-activated switch which combines the motion of 
two cams to operate a single switch. Specifically, this switch is used as 
a combination motor/feeler switch to halt ice production when the storage 
bin is full. 
In another aspect, the invention features an icemaker timer having a switch 
which is closed by rotating a connector between two contacts. By moving 
one of the contacts, the duration of switch closure may be conveniently 
varied, for example to provide a water valve control. 
In another aspect, the invention features a switch having two blades 
mounted such that, when closed, the blades make a wiping contact tending 
to clean the contact area and enhance reliability. 
In another aspect, the invention features an icemaker timer including a 
manual start button for starting the motor regardless of whether the 
thermostat indicates that there is ice in the mold, simplifying 
installation of the icemaker. 
In another aspect, the invention features an icemaker having a clutch 
mounted between the motor and ejector bar to permit slip therebetween so 
as to avoid stalling of the motor as the ejector bar presses upon ice in 
the mold, obviating the need for a more expensive stallable motor. 
In another aspect, the invention features an anti-back mechanism in the 
icemaker drive train to prevent an installer attempting to manually cycle 
the icemaker from unintentionally damaging the icemaker by rotating it 
backwards. The mechanism is a ring placed around a pinion which drives the 
ejector bar via a cam wheel. The ring meshes into the teeth of the cam 
wheel and pinion if the cam wheel is driven backward. 
In an alternative embodiment, the invention includes an icemaker having a 
combination deflector which not only deflects ice removed by the ejector 
from the ice mold, but also supports and lifts a feeler bar to determine 
whether the ice storage bin is full. 
The above and other objects, aspects, and advantages of the present 
invention shall be apparent from the accompanying drawings and description 
thereof.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
Referring to FIG. 1, an icemaker 90 in accordance with principles of the 
present invention includes a motor and timing assembly 100 and a mold 
assembly 102. The motor assembly 100 includes a timing unit 104 inside of 
a two-piece housing 106; timing unit 104 controls the timing of the 
icemaker and also rotates an ejector bar 112 to eject ice from the mold 
assembly 102. The mold assembly 102 includes a mold body 108 having an 
integral electric heater (not shown) on its underside. Water enters the 
mold 108 through a fill valve assembly 110 and forms ice. The ice is then 
pushed out of the mold by the fingers 113 of the ejector bar 112. 
It should be noted that timing unit 104 is fairly self-contained; that is, 
its has only a few mechanical or electrical connections to the remainder 
of the icemaker. The mechanical connections are limited to a few mounting 
screws (not shown) and the coupling to the ejector bar 112 (see FIG. 6, 
element 145), and are easily disconnectable. The electrical connections, 
which include a single ground connection leading from the motor and a set 
of connections 200 shown in FIG. 6, are similarly easily disconnectable. 
Thus, timing unit 104 can be quickly disconnected and removed for 
replacement, facilitating servicing of the icemaker. 
As shown in FIGS. 2A and 2B, counterclockwise rotation of the ejector bar 
112 causes fingers 113 to push cubes 118 of ice out of the mold body 108. 
When the cubes 118 emerge from the mold 108, they slide along the upper 
surface of deflector 114, and fall into a holding bin below the icemaker 
(not shown) where they are stored until needed. 
The mold assembly 102 also includes a feeler bar 116. After ice is ejected 
from the mold body, feeler bar 116 is lifted upwards and released onto the 
top of the ice in the holding bin. As shown in FIG. 1, the feeler bar 116 
includes a small loop 117 which is engaged by the outermost of the ejector 
bar fingers 113 as they rotate through the mold body 108. This causes the 
feeler bar 116 to move upwards, as shown in FIG. 2B. (In an alternative 
embodiment, cams molded into ejector bar 112 may engage loop 117 and lift 
feeler bar 116 rather than the outermost of fingers 113.) If, after being 
thus lifted, feeler bar 116 returns to a position near to its original 
position, indicating that the holding bin is not full, the icemaker 90 
performs another harvest cycle. If, on the other hand, the feeler bar 116 
does not return to its original position, indicating that the holding bin 
is full, the icemaker 90 halts operation and waits for the feeler bar 116 
to return to its original position (e.g., when enough ice in the holding 
bin is used, or sublimates). 
The functions of the preceding paragraph are accomplished by a feeler 
switch (blades 192 and 198) in the timing unit 104, discussed in detail 
below. This switch is actuated by motion of a feeler bar cap 120 which 
fits snugly over the end 121 of the feeler bar 116. As shown in FIGS. 1, 
2A and 2B, when the feeler bar 116 is raised and lowered by engagement of 
the ejector bar fingers 113, the feeler bar 116 rotates feeler bar cap 
120. This actuates the feeler switch inside of timing unit 104, in a 
manner described below. 
Combination Deflector/Feeler Arm 
Referring to FIG. 3, in an alternative embodiment of the mold assembly 108, 
the feeler bar and deflector bar are integrated into a single unit 130, 
132. In this embodiment, the ejector bar fingers 113 rotate in the 
opposite direction of that in FIG. 1. 
As illustrated in FIGS. 4A and 4B, in this alternative embodiment, the 
ejector bar 112 rotates clockwise through the mold body 108 to push ice 
cubes 118 out of the mold. As seen in FIG. 4A, during this operation, 
section 130 of the combined feeler/deflector forces the ice to eject 
downwards out of the mold body and into the holding bin below. Thereafter, 
as seen in FIG. 4B, the ejector bar fingers 113 engage section 130 of the 
combined feeler/deflector and force it upwards, lifting section 132 
upwards out of the holding bin. 
Some time thereafter, as the ejector bar fingers 113 continue to rotate, 
the fingers mesh through windows 131 (FIG. 3) in section 130 of the 
combined feeler/deflector, allowing the feeler/deflector to lower back 
down. As with the embodiment shown in FIG. 1, the motion of section 130 of 
the combined feeler/deflector is coupled to feeler bar cap 120, and used 
within the timing unit 104 to determine whether to perform another ice 
harvest cycle. If section 132 of the feeler/deflector comes to rest on ice 
within the storage bin, the feeler/deflector and feeler bar cap 120 will 
not return close to their original positions, and timing unit 104 will not 
initiate another harvest cycle; however, if the feeler/deflector and 
feeler bar cap 120 do return to their original positions, another harvest 
cycles will be initiated. 
FIG. 5, which is a perspective view taken from a reverse angle from FIGS. 1 
and 3, illustrates in greater detail the connection between the feeler bar 
116, feeler bar cap 120 and timing unit 104 for the icemaker 90 shown in 
FIG. 1. End 121 of feeler bar 116 inserts into a mating aperture 141 in 
feeler bar cap 120, causing feeler bar cap 120 to rotate with motion of 
feeler bar 116. 
Referring to FIGS. 5 and 6, the end of ejector bar 112 (FIG. 1) inserts 
into aperture 145 in cam wheel 142. Cam wheel 142 thereby delivers 
rotational torque from motor 146 to ejector bar 112. Motor 146 is a 
non-stall AC motor which operates at approximately one revolution per 
minute. Motor 146 drives a pinion gear 148 which engages cam wheel 142. 
The tooth ratio between pinion gear 148 and cam wheel 142 is 3:1, 
therefore, when motor 146 is running cam wheel 142 rotates at an angular 
velocity of 1 rotation every three minutes. 
Also shown in FIGS. 5 and 6 is feeler bar cam slider 140 (which can be seen 
in full in FIG. 7). This slider rotates about the same axis as cam wheel 
142. Finger 143 on feeler bar cap 120 engages into a slot 144 of a feeler 
bar cam slider 140, so that rotation of feeler bar cap 120 (in response to 
movement of feeler bar 116) is translated into rotation of feeler bar cam 
slider 140. Two positions of feeler bar cap 120 are shown in FIG. 6, 
illustrating the rotational movement imparted to feeler bar cam slider 140 
in response to raising and lowering of feeler bar 116. 
As noted in further detail below, raising and lowering feeler bar 116 
changes the electrical behavior of the icemaker, so that no ice is made 
whenever sufficient ice is in the storage bin, i.e., whenever feeler bar 
116 does not return to its down position after being lifted as described 
above. This feature may be further employed to provide a storage mode for 
the icemaker. To do so, cap 120 may be molded with a catch 149a in the 
form of a detent which mates with a similar detent 149b in housing 106 
(FIG. 1). 
FIGS. 5 and 6 also illustrate a third embodiment for raising and lowering 
feeler bar 116. In this embodiment, there is no bend 117 in feeler bar 116 
such as is shown in FIG. 1. Instead, cam wheel 142 includes a small pin 
147 which, by rotation of cam wheel 142, engages finger 143 of feeler bar 
cap 120 and thereby causes feeler bar cap 120 to rotate and raise feeler 
bar 116. After pin 147 has rotated past finger 143, feeler bar 116 is 
allowed to lower back into the holding bin and thereby sense the ice level 
in the bin. 
As shown in FIG. 5, if necessary to ensure that feeler bar 116 lowers 
properly, a spring 138 can be attached to feeler bar cap 120 to provide 
positive torque to feeler bar cap 120 tending to push feeler bar 116 back 
into the holding bin. 
Finally, FIG. 6 illustrates the connectors 200 (shown in more detail below) 
which electrically connect the switches inside of the timing unit to the 
remainder of the icemaker. As noted above, because these connectors are 
grouped together, the timing unit can be easily connected and disconnected 
from the remainder of the icemaker, simplifying maintenance. 
FIG. 7 is an exploded perspective view of the timing unit 104, taken from a 
reverse angle from FIG. 5, showing further details of the internal 
operation of the unit. Slider 140 includes a central hole 151 which rests 
on the hub 150 of cam wheel 142 and therefore slider 140 rotates on the 
same axis as cam wheel 142. 
The internal face of cam wheel 142 includes four actuating cams risers 152, 
154, 156, 158 which rotate with motion of the motor 146 and ejector bar 
112. Furthermore, slider 140 includes a fifth cam 160 which, when 
assembled to the cam wheel 142, fits between cam risers 152 and 154, and 
rotates therein with motion of the feeler bar. As discussed in more detail 
below, these five cams, and a fill timing cam 166, interact with four 
front switch blades 164 and four rear switch blades 162 to create desired 
electrical switching patterns operating the motor, heater, and water fill 
valve. 
Assembly of the timing unit 104 proceeds as follows: motor 146 is mounted 
with two mounting screws 170 to the main housing 172 of the timing unit 
104. Then, manual start switch 171 is inserted into aperture 173 in area 
176 of main housing 172, so that the end of switch 171 protrudes outside 
of housing 172. Thereafter, switch blades 162 and 164 are inserted into 
mounting area 176 in housing 172, and are held in position by two 
insulating plates 163 and 165. 
After the switch blades and insulating plates are mounted, fill timing cam 
166 is mounted by inserting its narrow end through aperture 177 and 
snapping knob 178 onto the end. Once this is completed, cam wheel 142 is 
mounted to housing 172 by inserting its hub 150 (carrying slider 140) 
through aperture 174 and fitting screw 175. 
Clutch 
The motor drive train is then assembled and connected to the motor 146 and 
cam wheel 142. Drive pinion 148 has a hollow center which accepts a 
triangular slip clutch 182, which is held in place by a cover 183. After 
the slip clutch 182 has been mounted in drive pinion 148, anti-back ring 
185 is placed around the outer gears of drive pinion 148, and pinion 148 
is placed over the drive shaft 180 of motor 146 and into engagement with 
the gears on the outer rim of cam wheel 142. 
As shown in FIG. 7, drive shaft 180 has a hexagonal shape. This hexagonal 
drive shaft engages the walls of the triangular slip clutch 182, providing 
a resilient spring-clutch engagement between drive shaft 180 and pinion 
148. FIG. 6 includes an end view of the completed assembly, showing 
hexagonal drive shaft 180 inside of triangular slip clutch 182, which is 
itself inside the hollow center of pinion 148 and held in place by cover 
183. 
Triangular slip clutch 182 is manufactured of a resilient spring metal. 
Under normal operating torque loads, the walls of triangular slip clutch 
will not bend significantly, and pinion 148 will rotate with drive shaft 
180. However, under high torque loads (under operating conditions noted 
below), the walls of triangular slip clutch 182 will resiliently bend 
outward under rotational pressure from drive shaft 180, allowing drive 
shaft 180 to rotate relative to pinion 148, i.e., allowing motor 146 to 
continue rotating without rotating cam wheel 142. As noted further below, 
by including this unique, inexpensive clutch into the motor drive train, 
the icemaker need not use a stallable motor; instead, the icemaker can use 
a less expensive non-stallable timing motor. 
FIGS. 8A and 8B are detailed views of the switch blades 162, 164 and 
insulating plates 163, 165 of FIG. 7, showing the assembly of the switch 
blades into switches. Switch blades 162 include four individual blades 
191, 192, 193 and 194, and blades 164 include four individual blades 196, 
197, 198 and 199. As seen in FIG. 8B, when switch blades 162 and 164 are 
assembled with insulating plates 163, 165, pairs of the individual blades 
191 and 199, 192 and 198, 193 and 197, and 194 and 196 respectively form 
four pairs of electrical switch contacts. These switches form electrical 
connections to control functions of the icemaker 90. The heater, valve, 
thermostat, and motor, and electrical power, are coupled to the connectors 
200 on the upper ends of blades 162 and 164, and are thereby electrically 
controlled by the four electrical switches. (Details of the circuits 
created by the four switches are provided in FIGS. 12A-12C.) 
FIG. 8B also illustrates the interaction between cam 166 and the switch 
blades. As shown in greater detail below, blade 196 engages the surface of 
cam 166 and is bent thereby inward and outward as cam 166 is rotated by 
movement of knob 178 (shown in FIG. 7). 
FIGS. 9A and 9B show the assembled switch blades 162, 164 and cam 166 
assembled to cam wheel 142. As illustrated, each of the four rotating cam 
risers 152, 154, 156, 158 respectively engages and manipulates one of the 
switch blade pairs 194/196, 193/197, 192/198 and 191/199. Thus, as cam 
wheel 142 rotates, it sequentially opens and closes individual switches to 
achieve the desired electro-mechanical operation of the icemaker. 
Blade pairs 193/197 and 191/199 form, respectively, the "heater" and "hold" 
switches, and operate as follows. The associated cam risers 156 and 152 
engage the switch blades 197 and 199 which face the cam risers, and press 
these switch blades away from cam wheel 142 and into the associated switch 
blades 193 and 191, making electrical contact. When the cam risers 156 and 
152 are not thus engaging the switch blades, the switch blades do not 
contact each other. Thus, the second and fourth switches are open whenever 
the associated cam risers 152 and 156 are not engaging blades 197 and 199; 
otherwise, the switches are closed. 
Water Valve Switch 
Blade pair 194 and 196 forms the "water valve" switch, which works 
differently from the heater and hold switches. In the water valve switch, 
blades 194 and 196 never contact each other; rather, the cam riser 
includes a moving connector 195 which engages blades 194 and 196 at the 
same time, creating an electrical connection therebetween. Blade 194 
engages the top surface of the connector 195 shown in FIG. 9A. Blade 196 
includes a tab 208 (FIGS. 8A-8B) which engages the side 209 (FIGS. 9A-9B) 
of connector 195, forming an electrical connection. 
Side 209 of connector 195 has a radially sloping surface. This surface is 
used in conjunction with tab 208 and cam 166 to adjust the duration of the 
contact between blades 194 and 196, and thereby adjust the length of time 
that the water valve is opened. As is apparent from FIG. 9A, cam 166 can 
be rotated to bend blade 196, and therefore tab 208, radially inward and 
outward with respect to cam wheel 142. In FIG. 9A, cam 166 has been 
rotated to its position of greatest radial deflection; in this position 
tab 208 contacts the outer surface 209 of connector 195 for a brief 
angular distance where connector 195 extends radially outward to its 
furthest extent. However, in FIG. 9B, cam 166 has been rotated to a 
position of lesser radial deflection; in this position tab 208 contacts 
the outer surface 209 of connector 195 for a greater angular distance, 
nearly throughout the angular length of connector 195. 
Thus, by cooperation of connector 195 and blades 194 and 196, rotation of 
cam 166 adjusts the duration of the closure of the water fill switch, and 
thereby (as illustrated in greater detail below) provides a cube size 
adjustment. 
FIG. 10 illustrates an alternative embodiment of cam wheel 142 for use in 
the embodiment of FIGS. 3, 4A and 4B in which the ejector bar rotates in a 
reversed direction. In the embodiment of FIG. 10, the cam risers 152-158 
rotate in an opposite direction to that shown in FIGS. 9A-9B, and contact 
195 has a differing profile. (The embodiment of FIG. 10 is used with a 
motor having a greater rotational speed than 1 RPM, thus contact 195 has a 
greater angular length.) Other than these modifications, the operation of 
the switches is substantially similar to the embodiment of FIGS. 9A and 
9B. 
Bi-actuated Feeler Bar Switch 
Referring again to FIGS. 9A and 9B, blade pair 192 and 198 forms the 
"feeler bar" switch, which operates in a yet different manner. 
In the feeler bar switch, the associated cam riser 154 engages the switch 
blade 192, i.e., the rearward switch blade, rather than (as in the motor 
and hold switches) the front switch blade 198. As illustrated, cam riser 
154 has a half-width, and front switch blade 198 has a cutaway section 210 
which extends around cam riser 154 such that the front blade 198 is not 
engaged by cam riser 154. Thus, rather than engaging the front blade 198, 
cam riser 154 engages the rearward blade 192, and thereby moves blade 192 
away from blade 198. 
The front blade 198 is actuated by slider 140 (shown in FIG. 9B). As noted 
above, slider 140 is rotated by feeler bar cap 120 in response to raising 
and lowering of the feeler bar 116 (FIG. 5). This rotation causes slider 
140 to engage and deflect front blade 198 toward and away from rearward 
blade 192. 
FIGS. 11-11D illustrate the operation of the feeler bar switch in greater 
detail. FIG. 11 is a full cross-sectional view of the switch blades 
showing generally the alignment of switch blades 162, 164 and the cam 
risers of cam wheel 142. FIGS. 11A-11D are partial cross-sectional views 
specifically illustrating the four orientations of blades 198 and 192 in 
response to engagement, or lack thereof, of slider 140 and cam riser 154. 
FIGS. 11A and 11B show the motion of the blades when feeler bar 116 is up 
(see FIG. 2B), indicating that there is sufficient ice in the storage bin 
(or that the icemaker has been locked off). In this state, rearward blade 
192 will not contact front blade 198, regardless of whether cam riser 154 
is actuating (FIG. 11A) or not actuating (FIG. 11B) rearward blade 192. 
However, as shown in FIGS. 11C and 11D, such is not the case when feeler 
bar 116 is down (see FIG. 2A), indicating that there is not sufficient ice 
in the storage bin. In this situation, blade 198 will contact blade 192 
whenever cam riser 154 is not actuating rearward blade 192 (FIG. 11C). 
However, when cam riser 154 is actuating rearward blade 192 (FIG. 11D), 
blade 198 will not contact blade 192. 
Thus, to summarize, when the feeler bar is up, the feeler switch will be 
open regardless of the position of the cam wheel 142. However, when the 
feeler bar is down, the feeler switch will be open when cam riser 154 is 
actuating rearward blade 192; otherwise, the feeler switch will be closed. 
Self-Cleaning Switch Mounting 
FIG. 11 illustrates mounting area 176 of housing 172 shown in FIG. 7, into 
which the assembled switches are attached. As shown, each of the switch 
blades 162 are mounted flush to an upper section 203 of mounting area 176. 
A small projecting rim 202 in mounting area 176 separates upper section 
203 from a lower section 204 which is spaced away from switch blades 162. 
Thus, the portion of switch blades 162 above rim 202 are held firmly 
against housing 172 and cannot bend; however, the portions of switch 
blades 162 projecting below rim 202 do not contact housing 172 and can 
bend inward into the housing for a distance before contacting lower 
section 204 of the housing. 
As a result of this arrangement, when one of the switch blades 164 is 
pushed into the mating one of the switch blades 162, closing the 
corresponding switch, both switch blades will bend under the contact 
pressure; however, the blades will not bend from the same pivot points. 
Switch blades 164 bend around the bottom edge of insulating plate 163, 
whereas switch blades 162 bend around rim 202. Because the blades bend at 
differing pivot points, as the blades are pressed into each other there is 
a wiping action at the point of contact. This wiping action tends to clean 
the contact points and thereby increases reliability. 
FIG. 12A illustrates an electrical circuit formed by the four switches and 
the other elements of the icemaker, which can be best understood by 
simultaneous reference to FIG. 8A which shows the corresponding switch 
blades and connectors. As shown in FIG. 12A, AC electrical power from the 
host refrigerator on line 211 is applied to one terminal of motor 146 and 
a heater coil 222. The second terminal of the motor is attached to 
connector 200a (FIG. 8A) which connects to switch blade 199 of hold switch 
214 and switch blade 198 of feeler switch 215. (Note that blades 198 and 
199 are formed of a common strip of metal, thereby creating an electrical 
connection therebetween.) The neutral line 212 from the refrigerator is 
connected to switch blade 191 of hold switch 214 by a second connector 
200b, as is one terminal of a thermostatic switch 224 (of the type which 
closes when cold) and a solenoid-controlled water valve 226. The opposing 
terminal of thermostatic switch 224 is connected to a third connector 200c 
and thus to switch blade 192 of feeler switch 215, blade 193 of heater 
switch 216, and blade 194 of valve switch 217. (Here again, blades 192, 
193 and 194 are formed of a common strip of metal, thereby creating an 
electrical connection therebetween.) The opposing terminal of heater 222 
is connected to a fifth connector 200e leading to blade 197 of heater 
switch 216. Finally, the opposing terminal of valve 226 is connected to a 
fourth connector 200d leading to blade 196 of valve switch 217. 
It should be noted that, in the circuit of FIG. 12A, each of the connectors 
200 connects to exactly one wire leading from other components of the 
icemaker. Two-wire connectors are difficult to manufacture, and therefore 
expensive. Thus, the circuits of FIG. 12A has a cost advantage in that 
they it does not require two-wire connectors. 
FIG. 12B illustrates an alternative circuit which, although producing the 
same electrical function and timing as the circuit of FIG. 12A, requires a 
different layout and switch blade design. Here, the neutral line 212 from 
the refrigerator is connected to one terminal of the motor 146 and heater 
222. The opposite terminal of motor 146 is connected to a terminal of hold 
switch 214 and a terminal of feeler switch 215. The opposite terminal of 
heater 222 is connected to a terminal of heater switch 216. AC power from 
the refrigerator is connected to the remaining terminal of hold switch 
214, a terminal of thermostat 224, and a terminal of valve switch 217. The 
remaining terminal of valve switch 217 is connected to a terminal of valve 
226, and the opposing terminal of valve 226 is connected to the remaining 
terminals of thermostat 224, feeler switch 215, and heater switch 216. 
The circuit of FIG. 12B would require a different layout than the circuit 
of FIG. 12A, requiring at least one more connector because of the 
isolation of valve switch 217. However, the circuit of FIG. 12B has the 
advantage that all of the switches connect and disconnect power from other 
circuit elements; in the circuit of FIG. 12A, some switches disconnect 
ground, rather than power, from circuit elements. As a result, a ground 
fault in the circuit of FIG. 12A may cause unintended current flow in 
circuit elements, whereas the same fault in the circuit of FIG. 12B would 
not cause such current flow. Foreign, and future U.S. electrical safety 
standards may necessitate use of a circuit such as shown in FIG. 12B. 
FIG. 12C illustrates an alternative circuit configured for use with a 
double-throw thermostatic switch 224. In this circuit, AC power from the 
refrigerator on line 211 connects to a terminal of hold switch 214 and the 
common terminal of double-throw thermostat 224. The remaining terminal of 
hold switch 214 connects to a terminal of motor 146 and a terminal of 
feeler switch 215. The remaining terminal of hold switch 214 connects to 
the closed-when-cold terminal of thermostat 224 and to a terminal of 
heater switch 216. The remaining terminal of heater switch 216 connects to 
heater 222. The closed-when-warm terminal of thermostat 224 connects to a 
terminal of valve switch 217. The remaining terminals of valve 226, heater 
222 and motor 146 all connect to neutral line 212 from the refrigerator. 
FIG. 12D shows a further alternative circuit, which achieves the same 
timing as the circuit of FIG. 12C. In this circuit, AC power from the 
refrigerator on line 211 is connected to a terminal of feeler switch 215 
and to a terminal of hold switch 214. The remaining terminal of feeler 
switch 215 connects to the common terminal of double-throw thermostat 224. 
The closed-when-cold terminal of thermostat 224, and the remaining 
terminal of hold switch 214, connect to a terminal of motor 146. The 
closed-when-warm terminal of thermostat 224 connects to a terminal of 
valve switch 217 and heater switch 216. The remaining terminal of valve 
switch 217 connects to a terminal of valve 226, and the remaining terminal 
of heater switch 216 connects to a terminal of heater 222. The neutral 
line 212 from the refrigerator connects to the remaining terminals of 
valve 226, heater 222 and motor 146. 
The double-throw thermostat circuits of FIGS. 12C and 12D provide 
essentially the same timing as the circuits of FIGS. 12A and 12B; the 
primary difference is that in the circuits of FIGS. 12A and 12B the heater 
operates while the valve is open and filling the mold with water, whereas 
in the circuits of FIGS. 12C and 12D the heater does not operate during 
this period. 
FIG. 13 shows the timing diagram produced by the circuit of FIG. 12A. At 
the beginning of a cycle, the hold and heater switches 214 and 216 are 
closed, and the feeler and heater switches 215 and 217 are open. Assume 
that at this time, the thermostat is closed, indicating that the icemaker 
is warm and that there is no ice in the mold. 
Under the above conditions, the heater is off, the valve is closed, and the 
timing motor is on. Because the motor is on, cam wheel 142 slowly rotates. 
Eventually, at time 230, connector 195 contacts blades 194 and 196, 
closing the valve switch 217. This causes valve 226 to open. 
Due to the wiring of the circuit of FIG. 12A, closing the valve switch 217 
also causes the heater to turn on (current flowing through the valve 
solenoid also flows through the heater). It is unnecessary that the heater 
turn on at this time, however; as noted above, the circuits of FIGS. 12C 
and 12D above which do not create this brief heating period require the 
use of a double-throw thermostat, which is more expensive than a 
single-throw thermostat. The circuit of FIG. 12A avoids this expense by 
allowing the heater to operate while the valve is open. Furthermore, there 
is an advantage to the circuit of FIG. 12A: the valve cannot open if the 
heater has failed and will not draw current. Thus, if the heater fails, 
the mold will not fill with water and freeze, making it significantly 
easier to service the icemaker. 
Valve 226 remains open, filling the mold with water, for a period 
determined by the position of water fill adjustment cam 166, as described 
above. Eventually, at time 231, 232, or 233, connector 195 releases 
contact with blades 194 and 196, opening the valve switch 217 and closing 
valve 226. The heater also turns off at this time. 
At this point, the mold is filled with warm water, and the icemaker 
prepares to enter a "sleep" mode to freeze the water into ice. Thus, at 
time 234, cam riser 156 disengages from blade 197, causing the heater 
switch 216 to open. Thereafter, at time 236, cam riser 154 disengages from 
blade 192. Assuming for the moment that the feeler bar is down (because 
the ice storage bin is not full), this causes the feeler switch 215 to 
close (as shown in FIG. 11C above). Finally, at time 238, cam riser 152 
disengages from blade 199, opening hold switch 214. Because thermostat 224 
is still warm (the warm water in the mold not having had sufficient time 
to freeze), this last transition causes the motor to halt. 
Over the following period of time, which is much longer than the other 
times illustrated in FIG. 13, the icemaker waits for the water in the mold 
to freeze. Eventually, at time 240, the water freezes into ice and reaches 
a sufficiently low temperature to close thermostat 224. (Thermostat 224 
may, for example, be of the type that closes at approximately 15 degrees 
and opens at approximately 36 degrees; choosing a thermostat 224 with 
thresholds near to 32 degrees reduces the energy consumed heating and 
cooling the mold.) 
Once thermostat 224 is closed (still assuming that the feeler bar 116 is 
down) current flows to motor 146 through thermostat 224 and feeler switch 
215, and motor 146 turns on and cam 142 begins rotating. Thereafter, as 
cam 142 continues rotating, at time 242 cam riser 152 re-engages blade 
199, closing hold switch 214 and creating a more direct path for current 
to flow to motor 146. 
Thereafter, at time 244, cam riser 154 re-engages blade 192, opening feeler 
switch 215. Motor 146 continues running because current may flow to motor 
146 through hold switch 214. 
Next, at time 246, cam riser 156 re-engages blade 197, causing heater 
switch 216 to close. This turns heater 222 on and begins melting the ice 
away from the mold body. 
As 146 motor continues running after time 246, eventually fingers 113 of 
ejector bar 112 engage the ice in the mold body. If the ice is not yet 
free from the mold body, torque builds up in the power train of the timing 
motor. Eventually, the walls of triangular slip clutch 182 bend to allow 
the hexagonal drive shaft 180 of motor 146 to continue rotating without 
rotating cam wheel 142 or ejector bar 112. This torquing and slipping 
repeats until the ice in the mold body ultimately melts free from the mold 
body. At this point, the cam wheel 142 and ejector bar 112 continue 
rotating as shown in FIGS. 2A and 2B and eject the ice from the mold body 
and into the storage bin below. 
Although the ice has been removed from the mold body, thermostat 224 will 
not immediately open. Rather, it will typically take more than three 
minutes for thermostat 224 to open after ice has been removed from the 
mold body. During this period, motor 146 remains on and the icemaker 
performs a second full cycle. 
During this second cycle, the icemaker continues through each of the switch 
openings and closings illustrated in FIG. 13; however, because the 
thermostat is closed throughout, no water enters the mold or is frozen. 
Thus, at time 230, when the valve switch 217 closes, the valve does not 
open because the valve is shorted out by the closed thermostat 224. 
Furthermore, at time 238, when the hold switch 214 opens, the motor does 
not stop running because thermostat 224 is closed and therefore current 
flows through thermostat 224 and feeler switch 215 to motor 146. 
At some time 248, the mold body warms sufficiently (the heater having been 
on for most of the additional cycle described above) to open thermostat 
224. Typically, when thermostat 224 opens, heater switch 216 will be 
closed, so that the heater 222 will be on and drawing current through 
thermostat 224. Thus, when thermostat 224 opens, most of the time it will 
open-circuit the heater current. If heater 222 has any significant 
inductance (which is often the case with a coil-shaped heater), this 
sudden open circuit will create an arc across the terminals of thermostat 
224. This arc, while not harmful to thermostat 224, will help to clean the 
contacts of thermostat 224 and eliminates the need for corrosion-resistant 
terminals in the thermostat, which are expensive. 
At this point, the icemaker has returned to the state depicted at the 
beginning of the timing diagram of FIG. 13, and the icemaker proceeds to 
refill the storage bin and generate a new batch of ice cubes. 
The preceding discussion was drawn on the assumption that feeler bar 116 
was down at the relevant times during the cycle. If, instead, feeler bar 
116 was up, the operation of the icemaker would have been different as 
described below. 
As shown in FIGS. 11A and 11B, when feeler bar 116 is up, feeler switch 215 
cannot close. Thus, when feeler bar 116 is up, at time 236 feeler switch 
215 does not close. If this is the case, after hold switch 214 opens at 
time 238, stopping motor 146, motor 146 will not re-start when thermostat 
224 closes at time 240. Rather, because feeler switch 215 is open, motor 
146 will remain off and the icemaker will not harvest the ice in the mold. 
The icemaker will only re-start when feeler bar 116 lowers, for example 
due to use or sublimation of ice in the storage bin, or because feeler bar 
116 is lowered from a locked-up position by the owner or installer. 
Lowering feeler bar 116 will allow feeler switch 215 to close, turning on 
motor 146 and causing the icemaker to continue through a cycle and harvest 
the ice in the mold. 
Initial testing of the icemaker raises special issues which will be 
appreciated from the following. When the icemaker is first installed, the 
installer typically tests the icemaker by waiting for it to cycle once and 
determining that it is creating ice cubes of the proper size and at the 
proper speed. 
Normally there is no difficulty in following this procedure; the installer 
simply plugs in the refrigerator and water supply, listens for the 
icemaker to draw water into the mold, and waits for the cubes to form and 
harvest. However, a potential problem occurs if the icemaker is assembled 
in such a manner that the cam wheel 142 is positioned between times 233 
and 242. If this occurs, a significant delay will be experienced: 
thermostat 224 will be open because the refrigerator has been off and is 
at ambient temperature. However, the mold will not fill with water because 
the cam wheel will initiate beyond time 233. Therefore, the icemaker will 
progress to time 238 and motor 146 will turn off without water in the 
mold. As described above, once in this state, the icemaker will not 
continue cycling until thermostat 224 closes. However, it can take an 
unacceptably long time for thermostat 224 to close under these conditions; 
at times as long or longer as it takes for water to freeze. As a result, 
the installer may be forced to wait twice the usual time: first to cool 
thermostat 224 in order to cycle far enough to put water in the mold, and 
then to freeze the water placed in the mold. 
To alleviate this difficulty, the icemaker includes a manual start switch 
171 (FIG. 7) which allows the installer to override the normal timing 
sequence. Manual start switch 171 is a pushbutton which is installed in 
mounting area 176 of housing 172. Manual start switch 171 is aligned with 
blades 191 and 199 (which form hold switch 214); when pressed, switch 171 
forces blade 191 into blade 199, closing hold switch 214 and thereby 
turning on motor 146. Thus, when installing a refrigerator or icemaker, if 
the installer does not hear the water valve open to fill the icemaker, the 
installer need only press switch 171 for long enough to cycle the icemaker 
past time 242, causing the icemaker to complete a cycle and fill the mold 
body. 
Installers have encountered the problem discussed above with previous 
icemaker designs, and have devised a different solution. That solution is 
to grasp the fingers 113 of ejector bar 112 and manually force a cycle of 
the icemaker. In the icemaker disclosed herein, doing this would force 
rotation of cam wheel 142. Triangular slip clutch 182 would bend, allow 
cam wheel 142 to rotate independently of the 146. This solution is clearly 
inferior to the use of a manual start switch, in that it not only requires 
intense manual effort, but also places unnecessary stress on the fingers 
of the ejector bar 112. Torque applied to the ejector bar to eject ice is 
distributed among all of the fingers, whereas the above procedure applies 
all of the torque to one or a few fingers. 
While the above method is inferior, it may not be possible to educate 
installers not to use it. Therefore, the icemaker is configured so that it 
will not be damaged by the above method. First, the ejector bar fingers 
are reinforced sufficiently to individually bear enough torque to cause 
the triangular slip clutch 182 to bend and allow the cam wheel 142 to turn 
independently of the motor 146. Second, the icemaker is configured to 
prevent damage to the switch blades when the cam wheel is manually 
rotated. Specifically, manual rotation of the cam wheel can cause damage 
to the switch blades if the cam wheel is unintentionally rotated 
backwards. The cam risers 152, 154, 156, 158 have bevels on their leading 
edges but not on their trailing edges; therefore, rotating the cam wheel 
backwards can damage the blades by jamming the blades into the unbevelled 
trailing edges of the cam risers. 
To prevent this kind of damage, the icemaker includes an anti-back 
mechanism in the gear power train. Specifically, as shown in FIGS. 6 and 
7, an anti-back ring 185 is placed around the motor drive pinion 148. This 
pinion includes a curved end 153 and an uncurved end 155. So long as the 
cam wheel 142 and pinion 148 are rotated in the correct direction 
indicated by arrows 157, curved end 153 of ring 185 rides smoothly along 
the top of the teeth of cam wheel 142. However, if the cam wheel and 
pinion are forced to rotate in the opposite direction, friction between 
ring 185 and pinion 148 causes end 155 of ring 185 to rotate into and jam 
between the teeth of pinion 148 and cam wheel 142, preventing further 
rotation. 
While the present invention has been illustrated by a description of 
various embodiments and while these embodiments have been described in 
considerable detail, it is not the intention of the applicants to restrict 
or in any way limit the scope of the appended claims to such detail. 
Additional advantages and modifications will readily appear to those 
skilled in the art. For example, to reduce noise and possible damage, it 
may be advantageous to bevel the trailing edges of the cam risers as well 
as the leading edges, so long as no excessive "bounce" (rapid on/off 
switching) results. The invention in its broader aspects is therefore not 
limited to the specific details, representative apparatus and method, and 
illustrative example shown and described. Accordingly, departures may be 
made from such details without departing from the spirit or scope of 
applicant's general inventive concept.