US 3828568 A
There is disclosed an icemaker for installation in a household refrigerator. An increase in ice production capability is provided by providing a cold air flow path around the exterior of the ice mold. Means can be provided to prevent cold air passage across the mold during ice harvesting.
Description (OCR text may contain errors)
United States Patent 1191 1111 3,828,568 Frazier Aug. 13, 1974 ICE MAKER 2,886,747 5/1959 DiebOld 317/234 3,025,679 3/1962 Keighley 62/186 X  Invent Loulsvlne, 3,146,606 9/1964 Grimes et al. 62/351 x Assignee: General Electric Company, Archer Louisville, Ky.
Primary Examiner-William E. Wayner  F 1972 Attorney, Agent, or Firm-Francis H. Boos  Appl. No.: 318,715
 ABSTRACT  U.S. Cl. 62/186, 62/351  Int. Cl. F25c l/06 There d'sclosed an cemaker for mstallanon m a 5 Field of Search 62/35l 356, 353 340 household refrigerator. An increase in ice production (52/426, capability is provided by providing a cold air flow path around the exterior of the ice mold. Means can be  References Cited provided to prevent cold air passage across the mold UNITED STATES PATENTS dumg harvestmg' 2,782,608 2/1957 French et al 62/356 X 6 Claims, 6 Drawing Figures PATENTEB AUG 1 3 m4 sum 1hr 3 PAIENIE we 1 31974 sum 2 BF 3 EiiliZ PAIENIEB ms x 31914 '3'.aaa.see
ICE MAKER The provision of icemakers in household refrigerators is quite common. Typical icemakers proposed by the prior art are found in U.S. Pats. No. 3,163,017 and 3,163,018. In the commercial design of these devices, the ice mold comprises a cast aluminum block having heat exchange fins thereon. Accordingly, the ice mold of the prior art is relatively massive thus requiring substantial material expense. In these disclosures, an ice mold having a plurality of upwardly facing ice cube cavities is disposed beside a motor and linkage mechanism for ejecting ice pieces from the cavities. Although these icemakers have proved acceptable, certain improvements in mounting flexibility, space conservation, ice making efficiency and ice harvesting efficiency are contemplated by this invention.
It has been learned that greater mounting flexibility and space conservation can be achieved by positioning the motor and linkage mechanism for the ice ejector below the ice mold rather than beside the same.
Ice making efficiency of the device of this invention is improved over that of the prior art by providing a cold air passage around the mold. Turbulent cold air movement in the passage results in improved heat transfer across the mold thereby resulting in greater ice production.
Ice harvesting efficiency is improved in the device of this invention by closingthe cold air passage at the inception of ice harvesting thereby minimizing heat transfer across the mold during the ice harvesting cy- IN THE DRAWINGS FIG. 1 is a cross sectional view of a cold storage appliance illustrating the icemaker of this invention in one operative configuration thereof;
FIG. 2 is an enlarged front elevation view of the icemaker of this invention, certain parts being broken away for clarity of illustration and illustrating the icemaker during the icemaking'cycle;
FIG. 3 is a broken view similar to FIG. 2, certain parts being omitted for clarity, illustrating the icemaker at the inception of the ice harvesting cycle;
FIG. 4 is a view similar to FIG. 3 illustrating the ejector mechanism in the ice piece ejecting position;
FIG. 5 is a horizontal cross sectional view of the icemaker of FIGS. 1-4 taken substantially along line 5-5 of FIG. 2 as viewed in the direction indicated by the arrows; and
FIG. 6 is a schematic view of a typical electrical control circuit which may be utilized with the icemaker of this invention.
Referring to FIG. 1, the icemaker 10 of this invention is illustrated as positioned in the freezing compartment cle. Consequently, a lower capacity heater may be utilized to warm the mold in order to free the ice pieces for ejection. Ice harvesting efficiency is also improved by the design of the ejector linkage mechanism.
It is an object of this invention to provide an ice maker having greater mounting flexibility, increased ice production capability, increased ice harvesting efficiency and achieving greater space utilization.
In summary, one aspect of this invention comprises an icemaker including a mold having an inner surface providing ice piece forming cavities and an outer surface; a housing around the mold, the housing and the outer mold surface defining therebetween a serpentine .path of cold air movement for abstracting heat from the mold; and means for harvesting ice from the mold.
Another aspect of this invention comprises a cold storage appliance having a freezing compartment defined by a plurality of walls and means for circulating cold air in the compartment; and an ice maker, in the compartment, comprising a mold having an inner surface providing ice piece forming cavities and an outer surface; a housing, independent of the compartment walls, around the mold and defining with the outer mold surface a path of cold air movement; and means for harvesting ice pieces from the cavities including a heater for warming the inner mold surface and means for removing ice pieces from the cavities.
A further aspect of this invention comprises an icemaker including a mold providing ice piece forming cavities, means providing a cold air passage in heat exchanging relation with the mold, means operative during ice harvesting for removing ice from the mold including a heater for warming the mold, and means operative during harvesting for restricting the passage.
Other aspects, features and advantages of this invention will become more apparent hereinafter.
12 of a cold storage appliance. The freezing compartment 12 is defined by a bottom wall 14, side walls 16, a back wall 18 and an open front which is closed by a conventional door (not shown). Opening through the back wall 13 is a duct 20 having therein a fan 22 for circulating cold air through the compartment 12. The fan 22 is typically controlled by a suitable thermostat (not shown) for starting and stopping cold air circulation in the compartment 12 in response to temperature therein. As will become more fully apparent hereinafter, the fan 22 comprises means for circulating cold air in the compartment 12 through the icemaker 10.
In order to assure that cold air passes through the icemaker 10 in the appropriate direction and in order to assure a substantial quantity of cold air moving through the icemaker 10, there is preferably provided a fitting 24 secured to the back wall 18 adjacent the duct 20. The fitting 24 acts to deliver a predetermined ratio of air from the fan 22 to a flexible conduit 26 connected to the icemaker 10.
For purposes of illustration, the icemaker I0 is illustrated adjacent the left side wall of the compartment 12 as viewed from the open front with an ice storage container 28 adjacent thereto. A prototype of the icemaker 10 is approximately 2- /2 inches wide X 7-% inches high X 9 inches deep. Accordingly, in many installations, the icemaker 10 may be placed on the freezer bottom wall with a shelf thereabove. As will be more fully apparent hereinafter, the icemaker 10 is unit handled and may be positioned adjacent either side or the back of the compartment 12.
Referring to FIGS. 2-6, the icemaker 10 comprises as major components a mold 30, a housing or baffle 32 defining with the mold 30 an undulating or serpentine cold air passage 34, ice harvesting means 36 including a heater 38, an ejector 40, driving means 42 and a linkage 44 interconnecting the driving means 42 and the ejector 40, a valve 46 for restricting the cold air passage 34 during harvesting, and a circuit 48 for controlling operation of the various components during the icemaking and ice harvesting cycles.
The mold 30 includes an inner surface 50 providing a pluraity of upwardly facing ice piece forming cavities 52. For all practical purposes, the inner mold surface 50 is substantially the same as illustrated in US. Pat. No. 3,163,017 and 3,331,215. The mold 30 also includes an outer moldsurface 54 of substantially the same configuration as the inner surface 50. The mold 30 is accordingly a thin wall mold as contrasted with the disclosures of the prior art referred to previously. The outer mold surface 54 presents an undulating surface rather than a planar surface as shown in the prior art. The mold 30 also includes a bottom wall 56 spaced below the bottom of the cavities 52 (FIG. 4) in order to accommodate the ejector 40 in the icemaking position thereof as shown in FIG. 2. The mold 30 may also comprise a top wall 58 for securement to the frame 60 of the icemaker 10.
Referring to FIGS. 1 and 2, there is provided a filling trough 62 connected to a suitable water line 64 passing through the side wall 16 of the freezing compartment 12. As will be apparent from FIG. 2, the filling trough 62 may be connected on either end of the icemaker 10 which enhances mounting. flexibility thereof. Water flowing through the conduit 64 and the filling trough 62 into the mold 30 is controlled by a valve 66 (FIG. 6) having a solenoid 68 which, when energized, opens the valve 66 to permit water to enter the filling trough 62 and mold 30. Since the opening into the filling trough 62 may be through the side wall, as illustrated, or through the end wall, mounting flexibility is further enhanced.
The housing 32 is captivated by the frame 60 between openings 70, 72 therein and is in surrounding relation to the mold 30. The direction of air movement along the passage 34 depends, of course, upon the natural circulation pattern. within the freezing compartment 12 or the induced circulation pattern afforded by the fitting 24 and the conduit 26. For purposes of illustration, air flow is illustrated from right to left in FIG. since it is desirable that the thermostat 74 be in heat transferring relation with the downstream ice forming cavity 52.
The housing 32 comprises side walls 76, 78 which undulate in an arrangement complementary to the undulations in the mold 30 thereby providing the undulating or serpentine air flow passage 34. The configuration of the air flow passage 34 and the distances between the mold 30 and the side walls 76, 78 are designed to achieve turbulent air flow in the passage 34 at volumetric air flows between 1 and CFM. Turbulent air flow in the passage 34 is highly desirable to avoid dead air spaces in the areas 80 between the ice piece forming sections. The housing 32 also comprises a bottom wall 82 underlying the mold 30 as seen most clearly in FIGS. 3 and 4. I
Testing of various prototypes of this invention has revealed interesting data. In an early prototype of the invention with a housing having planar side walls rather than undulating side walls with the cold air circulating fan on continuously, the elapsed time from filling of the ice piece cavities with water to freezing of the ice pieces was greater than 60 minutes. By incorporating means on the baffle side walls to create a serpentine cold air flow path and thereby provide turbulent air flow reduced the fill-to-freeze time to 40 minutes. It will be appreciated that the ice mold 30 and baffle 32 of this invention are substantially less expensive than the cast aluminum ice molds of the prior art. This is primarily the result of a lesser quantity of material in the mold 30 and the housing 32 and greatly simplified configuration.
The heater 38 comprises part of the ice harvesting means 36. For reasons more fully pointed out hereinafter, the heater 38 is a low power electrical resistance element in heat exchanging relation with the mold 30. After the thermostat 74 has sensed that the temperature in the downstream ice piece cavity 52 has declined to a predetermined value, the thermostat 74 closes. If the stop-start switch 8 is closed, as will be explained more fully hereinafter, the heater 38 is energized to commence the ice harvesting operation.
The ice piece ejector 40 is illustrated as being of generally conventional configuration and is quite similar to that disclosed in US. Pat. No. 3,163,018. The ejector 40 accordingly comprises a plurality of piston-like plates 86 formed integrally with the top of a thin elongate horizontal bar 88 which passes between the ice forming cavities. An ejector rod 90 is secured to the vertical movement. The bushing 94 includes one or more O-rings 96 for sealing against the rod 90. The bushing 94 is threaded into a collar 98 which is held by a clamp 100. In contrast with the amount of machining required in prior art ice molds, the only machining required in the mold 30 is the aperture in which the bushing 94 fits.
The driving means 42 comprises an electric motor 102 and a gear box 104 of conventional design. The gear box 104 provides a rotatable output 106. drivably connected to the linkage 44 for converting rotary motion of the output 106 into reciprocation of the ejector rod 90.
The linkage 44 comprises an enlarged hub 108 having thereon a crank or cam 110 spaced from the axis of the output 106. The cam 110 conveniently c0mprises a screw 112 threaded into the hub 108 and a roller 114 mounted for rotation thereon. The cam 110 is captivated in a generally horizontal slot 116 provided by a yoke 118 which is rigid with the ejector rod 90. The yoke 118 is rigid with a framework 120 which is constrained for vertical movement by a rod 122 passing through an opening 124 in the framework 120. It will accordingly be seen that the linkage 44 is illustrated as comprising a Scotch yoke.
FIGS. 2-4 illustrate respectively the icemaking position of the icemaker 10, the initiation of the ice harvesting cycle and the termination of the ice harvesting cycle. As the motor 102 is energized from the position of FIG. 2, the output 106 rotates thereby providing the cam 110 about the axis of the output 106. Revolution of the cam 110 causes the yoke 118 to move vertically as constrained by the rod 122.
The motor 102 and the heater 108 are energized substantially simultaneously. After an initial lost-motion movement of the linkage 44, the motor 102 stalls until the heater 38 melts a film of ice immediately adjacent the inner mold surface 50. As the heater 38 breaks the bond between the ice and the mold 30, the motor 102 begins movement thereby elevating the ejector 40. Consequently, the greatest force required during the ice harvesting operation is at the initiation of ejector movement. Accordingly, the linkage 44 is preferably designed to generate the greatest force on the ejector rod 90 at the inception of upward movement thereof. An analysis of the linkage 44 reveals that a large upward force produced thereby occurs when the cam lies in a sector 126 adjacent the bottom of the path of movement of the cam 110. Accordingly, it is highly desirable that the linkage 44 commence ice harvesting movement in the sector 126.
To this end, the motor 102 is de-energized by the circuit 48 on the downstroke of the ejector rod 90 and a biasing spring 128 is provided for biasing the rod 90 to its lower position and assuring full downstroke movement thereof as shown in FIG. 2.
The ice harvesting means 36 also includes a feeler arm 130 for sensing the quantity of ice in the container 28. The feeler arm 130 is illustrated as passing through the housing 32 and journalled by suitable bushings 132 therein. As shown best in FIG. 5, the feeler arm 130 is rigidly connected to a lever 134 which is in turn pinned to a member 136. The member 136 is constrained by a bracket 138 for vertical movement and includes, at the lower end thereof, a pair of switch actuating members 140, 142. The switch actuating members 140, 142 captivate a switch actuator 144 for the switch 84 illustrated in FIG. 6.
During ice harvesting the feeler arm 130 is raised out of the ice container 28 before ejection of the ice pieces and it thereafter drops into engagement with the ice pieces. To this end, there is provided an extension 146 underlying a bearing element 148 carried by the member 136. As the linkage 44 is actuated, the framework and the extension 146 thereon are elevated into contact with the bearing element 148. As suggested in FIG. 4, during each ice ejection cycle the extension 146 elevates the member 136 thereby raising the feeler arm substantially out of the container 28 and returns to the position as illustrated in FIG. 2, allowing member 136 to assume a position determined by the engagement of feeler arm 130 with the ice pieces.
As the container 28 fills with ice, the feeler arm 130 assumes a more or less horizontal position upon engaging the ice pieces. Ultimately, as the container 28 fills, the switch actuating member is held in an elevated position so that the switch actuator 144 opens the circuit leading to the motor 102 thereby preventing further harvesting of ice. As the container 28-is emptied, the feeler arm 130 again assumes a more nearly vertical position so that the switch actuating member 142 may engage the switch actuator 144 and close the stop-start switch 84. In the alternative, the switch 84 may be of the normally closed type such that downward movement of the member 136 allows the switch actuator 144 to return to the closed position.
An important part of the ice harvesting means 36 is the valve 46 for closing or restricting the cold air passage 34. The valve 46 includes a gate 150 mounted for movement in a suitable slot 152 between positions opening and closing the passage 34. The gate 150 is manipulated between these positions by an actuating arm 154. The actuating arm 154 is movably mounted by a pivot connection 156 which is conveniently secured to the gear box 104. The free end of the actuating arm 154 is connected to the gate 150 by a suitable lost motion connection. A cam follower 158 is mounted on a projection 160 extending from the arm 154. The follower 158 is captivated in a camming groove 162 on the back side of the hub 108. As shown in FIG. 2, the follower 158 is positioned by the-cam track 162 to depress the actuating arm 154 and thereby move the gate 150 out of the air passage 34. Since FIG.
2 illustrates the icemaking cycle of operation, air flow through the passage 34 is unimpeded. At the commencement of the ice harvesting cycle, the hub 108 is rotated toward the position in FIG. 3. The cam follower 158 is moved laterally of the pivot connection 156 thereby raising the actuating arm 154 and moving the gate 150 to the closed position. In the configuration of FIG. 3, it will be apparent that air flow through the passage 34 stops. By closing the valve 46, heat transfer from the inner mold surface 50 to the outer mold surface 54 is greatly reduced.
The reduction of heat transfer from the inner mold surface 50 to the outer mold surface 54 has two important advantages. With the valve 46 closed, the heater 38 needs only to warm the mold 30 sufficiently to break the ice adhesion bond. With the gate 46 open and cold air flowing through the passage 34, the heater 38 would necessarily be of greater capacity since a substantial quantity of heat would be transferred to the moving air stream rather than to the mold 30. Accordingly, a low power heater may be utilized. In prototypes of this invention, heaters having 3040 watt capacity have proved satisfactory compared to 180 watt heaters used on presently commercially available icemakers. An important practical sidelight of this improvement in operating efficiency is that the heretofore conventional overheat safety thermostat, which is normally in series with the thermostat 74, may be deleted since the maximum temperature rise of low power heaters is within the maximum allowable temperature rise for materials used in the icemaker 10.
There is another important advantage in ice harvesting efficiency afforded by this invention. Referring to FIG. 3, it will be apparent that the mold 30 is gaining heat immediately adjacent the heater 38 and giving up heat away from the heater 38. By reducing heat transfer efficiency during harvesting, the mold 30 does not need to be heated to as great a temperature to release the ice pieces in the cavities 52. Thus there is a reduction in total heat input required of the heater 38.
Because of the degradation of heat transfer efficiency during harvesting, more sophiscated design improvements become practical. For example, breaking the adhesion of the ice pieces in the end cavities creates a greater stress on the ejector 40 and operating assembly therefor because of the longer moment arm between the end cavities and the axis of ejector movement. This may be obviated, if desired, by controlling heat input to break the adhesion bond in a particular sequence, for example end ice pieces first.
The switching mechanism 164 used in the control of the icemaker 10 is substantially the same as illustrated in US. Pat. No. 3,163,018. The switching mechanism 164 comprises sequentially actuated switches 166, 168. The switch 166 controls an energizing circuit for the motor 102 while the switch 168 controls the solenoid 68 of the filling valve 66. The switches 166,168 are conveniently ganged together and manipulated by an actuator 170 having thereon a cam follow 172 which engages the periphery 174 of the hub 108. The hub periphery 174 includes a depression 176 allowing selfbiased movement of the actuator 170 toward the switch open position illustrated in FIG. 6.
At the termination of the icemaking cycle, the thermostat 74 closes. If the feeler arm 130 senses a lack of ice in the container 28, the switch 84 is closed. Thus, a circuit is completed to the heater 38 and the motor This rotation of the hub 108 initiates a plurality of functions including closing of the valve 46 and closing of the switch 166.
The motor 102 stalls until the adhesion bond between the ice pieces and the inner mold surface 50 is substantially weakened. The force imposed by the driving means 42 and linkage 44 is then sufficient to complete breakage of the'adhesion bond and allow upward movement of the rod 90 and ejector 40 toward the position illustrated in FIG. 4. As the ice cubes eject from the mold 30, they engage a suitable deflector 178 and fall into the container 24. Continued rotation of the hub 108 causes downward movement of the ejector 40 and rod 90 from the position shown in FIG. 4 toward the position shown in FIG. 2. During the heating period, thermostat 74 opens so that when the follower 172 passes into the depression 176, opening switch 166, the motor 102 and heater 38 are de-energized. The hub 108 begins to coast to a stop. Engagement of the cam 110 with the bias spring128 causes the icemaker to come to rest in preparation for an icemaking cycle.
As is apparent from FIGS. 1 and 6, a pair of leads 180, 182, which energize the circuit 48, are encased in suitable insulation to form a cable 184 passing through the freezer side wall 16.
The icemaker affords a number of important advantages previously mentioned. In addition, the icemaker 10 may be tested for operability prior to installation in a refrigerator.
1. A self-harvesting icemaker, comprising: a mold providing ice piece forming cavities, first means defining a cold air passage in heat exchanging relationship with the mold, second means for directing cold air -'through said cold air passage, third means operative during harvesting for removing ice from the mold, said third means including a heater for warming the mold, and fourth means operative during harvesting for restricting the cold air passage and precluding cold air circulation through said cold air passage.
2. The self-harvesting icemaker of claim 1, wherein the first means is of a size sufficient relative to the mold for providing turbulent air flow at a preselected air flow rate.
3. The self-harvesting icemaker of claim 2, wherein the preselected air flow rate is in the range of between l-lO CFM.
4. The icemaker of claim 1 wherein the fourth means comprises a valve and means for moving the valve between positions opening and closing the passage.
5. The icemaker of claim 4 further comprising means for substantially simultaneously energizing the heater and the means for moving the valve.
6. The icemaker of claim 4 wherein the third means includes an ejector, means for moving the ejector through the cavities, and means for energizing the heater and for moving the valve to the passage closing position prior to moving the ejector through the cavities.