Patent Publication Number: US-9890986-B2

Title: Clear ice maker and method for forming clear ice

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of and claims priority to U.S. patent application Ser. No. 13/713,218, filed Dec. 13, 2012, entitled CLEAR ICE MAKER AND METHOD FOR FORMING CLEAR ICE, issued as U.S. Pat. No. 9,476,629. The aforementioned related application is hereby incorporated herein by reference in its entirety. 
     The present application is related to, and hereby incorporates by reference herein the entire disclosures of, the following applications for United States patents: U.S. patent application Ser. No. 13/713,283, entitled ICE MAKER WITH ROCKING COLD PLATE, filed Dec. 13, 2012, U.S. patent application Ser. No. 13/713,199, entitled CLEAR ICE MAKER WITH WARM AIR FLOW, filed on Dec. 13, 2012; U.S. patent application Ser. No. 13/713,296, entitled CLEAR ICE MAKER WITH VARIED THERMAL CONDUCTIVITY, filed on Dec. 13, 2012; U.S. patent application Ser. No. 13/713,244, entitled CLEAR ICE MAKER, filed on Dec. 13, 2012; U.S. patent application Ser. No. 13/713,206, entitled LAYERING OF LOW THERMAL CONDUCTIVE MATERIAL ON METAL TRAY, filed on Dec. 13, 2012; U.S. patent application Ser. No. 13/713,233, entitled CLEAR ICE MAKER, filed on Dec. 13, 2012; U.S. patent application Ser. No. 13/713,228, entitled TWIST HARVEST ICE GEOMETRY, filed; U.S. patent application Ser. No. 13/713,262, entitled COOLING SYSTEM FOR ICE MAKER, filed on Dec. 13, 2012; and U.S. patent application Ser. No. 13/713,253, entitled CLEAR ICE MAKER AND METHOD FOR FORMING CLEAR ICE, filed on Dec. 13, 2012. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to an ice maker for making substantially clear ice pieces, and methods for the production of clear ice pieces. More specifically, the present invention generally relates to an ice maker and methods which are capable of making substantially clear ice without the use of a drain. 
     BACKGROUND OF THE INVENTION 
     During the ice making process when water is frozen to form ice cubes, trapped air tends to make the resulting ice cubes cloudy in appearance. The trapped air results in an ice cube which, when used in drinks, can provide an undesirable taste and appearance which distracts from the enjoyment of a beverage. Clear ice requires processing techniques and structure which can be costly to include in consumer refrigerators and other appliances. There have been several attempts to manufacture clear ice by agitating the ice cube trays during the freezing process to allow entrapped gases in the water to escape. 
     SUMMARY OF THE INVENTION 
     One aspect of the present disclosure, an ice maker assembly includes an ice tray having an ice forming plate with a top surface, a bottom surface and upstanding edges around a perimeter of the ice forming plate. A containment wall extends upwardly around the perimeter of the ice forming plate. The containment wall has a slot extending along a lower portion of the containment wall. The slot receives the upstanding edges of the ice forming plate to form the ice tray. A fluid line is configured to dispense water onto the top surface of the ice forming plate. A mechanical oscillating mechanism is coupled to the ice tray. The oscillating mechanism begins to rotate the tray in a rocking cycle about a transverse axis of the ice forming plate after ice has started to form along the top surface. 
     According to another aspect of the present disclosure, a method of forming ice in an ice maker includes the steps of: dispensing water onto a top surface of an ice forming plate of an ice tray which has a top surface, a bottom surface and upstanding edges around the perimeter of the ice forming plate; positioning a containment wall around the perimeter of the ice forming plate; positioning a slot extending along a lower portion of the containment wall; positioning the upstanding edges of the ice forming plate in the slot to form the ice tray; cooling a bottom surface of the ice forming plate; forming a layer of ice on the top surface of the ice forming plate from the water; and actuating a mechanical oscillator after the layer of ice has formed on the top surface of the ice forming plate. 
     According to another aspect of the present disclosure, a method of forming ice in an ice maker, includes the steps of: dispensing water onto a top surface of an ice forming plate, the ice forming plate having a top surface, a bottom surface and upstanding edges around a perimeter of the ice forming plate; positioning a containment wall extending upwardly around the perimeter of the ice forming plate, the containment wall having a slot; positioning the upstanding edges of the ice forming plate into the slot to form an ice tray; cooling the ice forming plate until the water on the top surface of the ice forming plate forms a layer of ice on the top surface of the ice forming plate; actuating a microprocessor controlled mechanical oscillation mechanism; and rotating the tray in a rocking cycle until substantially all of the water dispensed onto the top surface of the ice forming plate has frozen. 
     These and other features, advantages, and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a top perspective view of an appliance having an ice maker of the present invention; 
         FIG. 2  is a front view of an appliance with open doors, having an ice maker of the present invention; 
         FIG. 3  is a flow chart illustrating one process for producing clear ice according to the invention; 
         FIG. 4  is a top perspective view of a door of an appliance having a first embodiment of an ice maker according to the present invention; 
         FIG. 5  is a top view of an ice maker according to the present invention; 
         FIG. 6  is a cross sectional view of an ice maker according to the present invention taken along the line  6 - 6  in  FIG. 5 ; 
         FIG. 7A  is a cross sectional view of an ice maker according to the present invention, taken along the line  7 - 7  in  FIG. 5 , with water shown being added to an ice tray; 
         FIG. 7B  is a cross sectional view the ice maker of  FIG. 7A , with water added to the ice tray; 
         FIGS. 7C-7E  are cross sectional views of the ice maker of  FIG. 7A , showing the oscillation of the ice maker during a freezing cycle; 
         FIG. 7F  is a cross sectional view of the ice maker of  FIG. 7A , after completion of the freezing cycle; 
         FIG. 8  is a perspective view of an appliance having an ice maker of the present invention and having air circulation ports; 
         FIG. 9  is a top perspective view of an appliance having an ice maker of the present invention and having an ambient air circulation system; 
         FIG. 10  is a top perspective view of an ice maker of the present invention installed in an appliance door and having a cold air circulation system; 
         FIG. 11  is a top perspective view of an ice maker of the present invention, having a cold air circulation system; 
         FIG. 12A  is a bottom perspective view of an ice maker of the present invention in the inverted position and with the frame and motors removed for clarity; 
         FIG. 12B  is a bottom perspective view of the ice maker shown in  FIG. 12A , in the twisted harvest position and with the frame and motors removed for clarity; 
         FIG. 13  is a circuit diagram for an ice maker of the present invention; 
         FIG. 14  is a graph of the wave amplitude response to frequency an ice maker of the present invention; 
         FIG. 15  is a top perspective view of a second embodiment of an ice maker according to the present invention; 
         FIG. 16  is a top perspective view of a disassembled ice maker according to the present invention illustrating the coupling between an ice tray and driving motors; 
         FIG. 17  is an exploded top perspective, cross sectional view of an ice maker according to the present invention; 
         FIG. 18  is a partial top perspective, cross sectional view of an ice maker according to the present invention; 
         FIG. 19  is a side elevational view of an ice maker according to the present invention; 
         FIG. 20  is an end view of an ice maker according to the present invention; 
         FIG. 21  is a cross sectional view taken along line  21 - 21  in  FIG. 19 ; 
         FIG. 22  is a cross sectional view taken along line  22 - 22  in  FIG. 19 ; 
         FIG. 23  is an exploded side cross sectional view of an ice maker according to the present embodiment; 
         FIG. 24  is a top perspective view of a grid for an ice maker of the present invention; 
         FIG. 25  is a top perspective view of an ice forming plate, containment wall, thermoelectric device and shroud for an ice maker of the present invention; 
         FIG. 26  is a top perspective view of a thermoelectric device for an ice maker of the present invention; 
         FIG. 27  is a top perspective view of an ice maker with a housing and air duct according to the present invention; 
         FIG. 28  is a bottom perspective view of the ice maker with a housing and air duct according to the present invention; 
         FIG. 29  is a top perspective view of an ice maker with an air duct according to the present invention; 
         FIG. 30  is a top perspective cross sectional view of an ice maker with an air duct according to the embodiment shown in  FIG. 29 ; 
         FIG. 31A  is an end view of an ice maker according to the present invention in the neutral position with a cold air circulation system, and with the frame and motors removed for clarity; 
         FIGS. 31B-C  are end views of the ice maker shown in  FIG. 31A , showing the oscillating positions of the ice maker in the freezing cycle; 
         FIG. 31D  is an end view of the ice maker shown in  FIG. 31A  as inverted for the harvest cycle; 
         FIGS. 32A and 32B  are end views of the ice maker shown in  FIG. 31 , showing the inversion and rotation of the grid when in the harvest cycle; 
         FIGS. 33A-33D  are top perspective views of an ice maker according to the present invention, during harvesting, through its transition from the neutral position ( 33 A), inversion ( 33 B), rotation of the grid ( 33 C), and twisting of the grid ( 33 D); 
         FIG. 34  is a top perspective view of another embodiment of an ice maker according to the present invention; 
         FIG. 35A  is a top perspective view of an ice tray and cooling element according to the present invention; and 
         FIG. 35B  is a cross sectional view taken along the line  35 B- 35 B in  FIG. 35A . 
     
    
    
     DETAILED DESCRIPTION 
     For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivates thereof shall relate to the ice maker assembly  52 ,  210  as oriented in  FIG. 2  unless stated otherwise. However, it is to be understood that the ice maker assembly may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. 
     Referring initially to  FIGS. 1-2 , there is generally shown a refrigerator  50 , which includes an ice maker  52  contained within an ice maker housing  54  inside the refrigerator  50 . Refrigerator  50  includes a pair of doors  56 ,  58  to the refrigerator compartment  60  and a drawer  62  to a freezer compartment (not shown) at the lower end. The refrigerator  50  can be differently configured, such as with two doors, the freezer on top, and the refrigerator on the bottom or a side-by-side refrigerator/freezer. Further, the ice maker  52  may be housed within refrigerator compartment  60  or freezer compartment or within any door of the appliance as desired. The ice maker could also be positioned on an outside surface of the appliance, such as a top surface as well. 
     The ice maker housing  54  communicates with an ice cube storage container  64 , which, in turn, communicates with an ice dispenser  66  such that ice  98  can be dispensed or otherwise removed from the appliance with the door  56  in the closed position. The dispenser  66  is typically user activated. 
     In one aspect, the ice maker  52  of the present invention employs varied thermal input to produce clear ice pieces  98  for dispensing. In another aspect the ice maker of the present invention employs a rocking motion to produce clear ice pieces  98  for dispensing. In another, the ice maker  52  uses materials of construction with varying conductivities to produce clear ice pieces for dispensing. In another aspect, the icemaker  52  of the present invention is a twist-harvest ice maker  52 . Any one of the above aspects, or any combination thereof, as described herein may be used to promote the formation of clear ice. Moreover, any aspect of the elements of the present invention described herein may be used with other embodiments of the present invention described, unless clearly indicated otherwise. 
     In general, as shown in  FIG. 3 , the production of clear ice  98  includes, but may not be limited to, the steps of: dispensing water onto an ice forming plate  76 , cooling the ice forming plate  76 , allowing a layer of ice to form along the cooled ice forming plate  76 , and rocking the ice forming plate  76  while the water is freezing. Once the clear ice  98  is formed, the ice  98  is harvested into a storage bin  64 . From the storage bin  64 , the clear ice  98  is available for dispensing to a user. 
     In certain embodiments, multiple steps may occur simultaneously. For example, the ice forming plate  76  may be cooled and rocked while the water is being dispensed onto the ice forming plate  76 . However, in other embodiments, the ice forming plate  76  may be held stationary while water is dispensed, and rocked only after an initial layer of ice  98  has formed on the ice forming plate  76 . Allowing an initial layer of ice to form prior to initiating a rocking movement prevents flash freezing of the ice or formation of a slurry, which improves ice clarity. 
     In one aspect of the invention, as shown in  FIGS. 4-12 , an ice maker  52  includes a twist harvest ice maker  52  which utilizes oscillation during the freezing cycle, variations in conduction of materials, a cold air  182  flow to remove heat from the heat sink  104  and cool the underside of the ice forming plate  76  and a warm air  174  flow to produce clear ice pieces  98 . In this embodiment, one driving motor  112 ,  114  is typically present on each end of the ice tray  70 . 
     In the embodiment depicted in  FIGS. 4-12 , an ice tray  70  is horizontally suspended across and pivotally coupled to stationary support members  72  within an ice maker housing  54 . The housing  54  may be integrally formed with a door liner  73 , and include the door liner  73  with a cavity  74  therein, and a cover  75  pivotally coupled with a periphery of the cavity  74  to enclose the cavity  74 . The ice tray  70 , as depicted in  FIG. 4 , includes an ice forming plate  76 , with a top surface  78  and a bottom surface  80 . Typically, a containment wall  82  surrounds the top surface  78  of the ice forming plate  76  and extends upwards around the periphery thereof. The containment wall  82  is configured to retain water on the top surface  78  of the ice forming plate  76 . A median wall  84  extends orthogonally from the top surface  78  of the ice forming plate  76  along a transverse axis thereof, dividing the ice tray  70  into at least two reservoirs  86 ,  88 , with a first reservoir  86  defined between the median wall  84  and a first sidewall  90  of the containment wall  82  and a second reservoir  88  defined between the median wall  84  and a second sidewall  92  of the containment wall  82 , which is generally opposing the first sidewall  90  of the containment wall  82 . Further dividing walls  94  extend generally orthogonally from the top surface  78  of the ice forming plate  76  generally perpendicularly to the median wall  84 . These dividing walls  94  further separate the ice tray  70  into an array of individual compartments  96  for the formation of clear ice pieces  98 . 
     A grid  100  is provided, as shown in  FIGS. 4-8B  which forms the median wall  84  the dividing walls  94 , and an edge wall  95 . As further described, the grid  100  is separable from the ice forming plate  76  and the containment wall  82 , and is preferably resilient and flexible to facilitate harvesting of the clear ice pieces  98 . 
     As shown in  FIG. 6 , a thermoelectric device  102  is physically affixed and thermally connected to the bottom surface  80  of the ice forming plate  76  to cool the ice forming plate  76 , and thereby cool the water added to the top surface  78  of the ice forming plate  76 . The thermoelectric device  102  is coupled to a heat sink  104 , and transfers heat from the bottom surface  80  of the ice forming plate  76  to the heat sink  104  during formation of clear ice pieces  98 . One example of such a device is a thermoelectric plate which can be coupled to a heat sink  104 , such as a Peltier-type thermoelectric cooler. 
     As shown in  FIGS. 5 and 7A-7F , in one aspect the ice tray  70  is supported by and pivotally coupled to a rocker frame  110 , with an oscillating motor  112  operably connected to the rocker frame  110  and ice tray  70  at one end  138 , and a harvest motor  114  operably connected to the ice tray  70  at a second end  142 . 
     The rocker frame  110  is operably coupled to an oscillating motor  112 , which rocks the frame  110  in a back and forth motion, as illustrated in  FIGS. 7A-7F . As the rocker frame  110  is rocked, the ice tray  70  is rocked with it. However, during harvesting of the clear ice pieces  98 , the rocker frame remains  110  stationary and the harvest motor  114  is actuated. The harvest motor  114  rotates the ice tray  70  approximately 120°, as shown in  FIGS. 8A and 8B , until a stop  116 ,  118  between the rocker frame  110  and ice forming plate  76  prevents the ice forming plate  76  and containment wall  82  from further rotation. Subsequently, the harvest motor  114  continues to rotate the grid  100 , twisting the grid  100  to release clear ice pieces  98 , as illustrated in  FIG. 8B . 
     Having briefly described the overall components and their orientation in the embodiment depicted in  FIGS. 4-8B , and their respective motion, a more detailed description of the construction of the ice maker  52  is now presented. 
     The rocker frame  110  in the embodiment depicted in  FIGS. 4-8B  includes a generally open rectangular member  120  with a longitudinally extending leg  122 , and a first arm  124  at the end  138  adjacent the oscillating motor  112  and coupled to a rotary shaft  126  of the oscillating motor  112  by a metal spring clip  128 . The oscillating motor  112  is fixedly secured to a stationary support member  72  of the refrigerator  50 . The frame  110  also includes a generally rectangular housing  130  at the end  142  opposite the oscillating motor  112  which encloses and mechanically secures the harvest motor  114  to the rocker frame  110 . This can be accomplished by snap-fitting tabs and slots, threaded fasteners, or any other conventional manner, such that the rocker frame  110  securely holds the harvest motor  114  coupled to the ice tray  70  at one end  138 , and the opposite end  142  of the ice tray  70  via the arm  124 . The rocker frame  110  has sufficient strength to support the ice tray  70  and the clear ice pieces  98  formed therein, and is typically made of a polymeric material or blend of polymeric materials, such as ABS (acrylonitrile, butadiene, and styrene), though other materials with sufficient strength are also acceptable. 
     As shown in  FIG. 5 , the ice forming plate  76  is also generally rectangular. As further shown in the cross-sectional view depicted in  FIG. 6 , the ice forming plate  76  has upwardly extending edges  132  around its exterior, and the containment wall  82  is typically integrally formed over the upwardly extending edges  132  to form a water-tight assembly, with the upwardly extending edge  132  of the ice forming plate  76  embedded within the lower portion of the container wall  82 . The ice forming plate  76  is preferably a thermally conductive material, such as metal. As a non-limiting example, a zinc-alloy is corrosion resistant and suitably thermally conductive to be used in the ice forming plate  76 . In certain embodiments, the ice forming plate  76  can be formed directly by the thermoelectric device  102 , and in other embodiments the ice forming plate  76  is thermally linked with thermoelectric device  102 . The containment walls  82  are preferably an insulative material, including, without limitation, plastic materials, such as polypropylene. The containment wall  82  is also preferably molded over the upstanding edges  132  of the ice forming plate  76 , such as by injection molding, to form an integral part with the ice forming plate  76  and the containment wall  82 . However, other methods of securing the containment wall  82 , including, without limitation, mechanical engagement or an adhesive, may also be used. The containment wall  82  may diverge outwardly from the ice forming plate  76 , and then extend in an upward direction which is substantially vertical. 
     The ice tray  70  includes an integral axle  134  which is coupled to a drive shaft  136  of the oscillating motor  112  for supporting a first end of the ice tray  138 . The ice tray  70  also includes a second pivot axle  140  at an opposing end  142  of the ice tray  70 , which is rotatably coupled to the rocker frame  110 . 
     The grid  100 , which is removable from the ice forming plate  76  and containment wall  82 , includes a first end  144  and a second end  146 , opposite the first end  144 . Where the containment wall  82  diverges from the ice freezing plate  76  and then extends vertically upward, the grid  100  may have a height which corresponds to the portion of the containment wall  82  which diverges from the ice freezing plate  76 . As shown in  FIG. 4 , the wall  146  on the end of the grid  100  adjacent the harvest motor  114  is raised in a generally triangular configuration. A pivot axle  148  extends outwardly from the first end of the grid  144 , and a cam pin  150  extends outwardly from the second end  146  of the grid  100 . The grid  100  is preferably made of a flexible material, such as a flexible polymeric material or a thermoplastic material or blends of materials. One non-limiting example of such a material is a polypropylene material. 
     The containment wall  82  includes a socket  152  at its upper edge for receiving the pivot axle  148  of the grid  100 . An arm  154  is coupled to a drive shaft  126  of the harvest motor  114 , and includes a slot  158  for receiving the cam pin  150  formed on the grid  100 . 
     A torsion spring  128  typically surrounds the internal axle  134  of the containment wall  82 , and extends between the arm  154  and the containment wall  82  to bias the containment wall  82  and ice forming plate  76  in a horizontal position, such that the cam pin  150  of the grid  100  is biased in a position of the slot  158  of the arm  154  toward the ice forming plate  76 . In this position, the grid  100  mates with the top surface  78  of the ice forming plate  76  in a closely adjacent relationship to form individual compartments  96  that have the ice forming plate defining the bottom and the grid defining the sides of the individual ice forming compartments  96 , as seen in  FIG. 6 . 
     The grid  100  includes an array of individual compartments  96 , defined by the median wall  84 , the edge walls  95  and the dividing walls  94 . The compartments  96  are generally square in the embodiment depicted in  FIGS. 4-8B , with inwardly and downwardly extending sides. As discussed above, the bottoms of the compartments  96  are defined by the ice forming plate  76 . Having a grid  100  without a bottom facilitates in the harvest of ice pieces  98  from the grid  100 , because the ice piece  98  has already been released from the ice forming plate  76  along its bottom when the ice forming piece  98  is harvested. In the shown embodiment, there are eight such compartments. However, the number of compartments  96  is a matter of design choice, and a greater or lesser number may be present within the scope of this disclosure. Further, although the depiction shown in  FIG. 4  includes one median wall  84 , with two rows of compartments  96 , two or more median walls  84  could be provided. 
     As shown in  FIG. 6 , the edge walls  95  of the grid  100  as well as the dividing walls  94  and median wall  84  diverge outwardly in a triangular manner, to define tapered compartments  96  to facilitate the removal of ice pieces  98  therefrom. The triangular area  162  within the wall sections may be filled with a flexible material, such as a flexible silicone material or EDPM (ethylene propylene diene monomer M-class rubber), to provide structural rigidity to the grid  100  while at the same time allowing the grid  100  to flex during the harvesting step to discharge clear ice pieces  98  therefrom. 
     The ice maker  52  is positioned over an ice storage bin  64 . Typically, an ice bin level detecting arm  164  extends over the top of the ice storage bin  64 , such that when the ice storage bin  64  is full, the arm  164  is engaged and will turn off the ice maker  52  until such time as additional ice  98  is needed to fill the ice storage bin  64 . 
       FIGS. 7A-7F  and  FIGS. 8A-8B  illustrate the ice making process of the ice maker  52 . As shown in  FIG. 7A , water is first dispensed into the ice tray  70 . The thermoelectric cooler devices  102  are actuated and controlled to obtain a temperature less than freezing for the ice forming plate  76 . One preferred temperature for the ice forming plate  76  is a temperature of from about −8° F. to about −15° F., but more typically the ice forming plate is at a temperature of about −12° F. At the same time, approximately the same time, or after a sufficient time to allow a thin layer of ice to form on the ice forming plate, the oscillating motor  12  is actuated to rotate the rocker frame  110  and ice cube tray  70  carried thereon in a clockwise direction, through an arc of from about 20° to about 40°, and preferably about 30°. The rotation also may be reciprocal at an angle of about 40° to about 80°. The water in the compartments  96  spills over from one compartment  96  into an adjacent compartment  96  within the ice tray  70 , as illustrated in  FIG. 7C . The water may also be moved against the containment wall  82 ,  84  by the oscillating motion. Subsequently, the rocker frame is rotated in the opposite direction, as shown in  FIG. 7D , such that the water spills from one compartment  96  into and over the adjacent compartment  96 . The movement of water from compartment  96  to adjacent compartment  96  is continued until the water is frozen, as shown in  FIGS. 7E and 7F . 
     As the water cascades over the median wall  84 , air in the water is released, reducing the number of bubbles in the clear ice piece  98  formed. The rocking may also be configured to expose at least a portion of the top layer of the clear ice pieces  98  as the liquid water cascades to one side and then the other over the median wall  84 , exposing the top surface of the ice pieces  98  to air above the ice tray. The water is also frozen in layers from the bottom (beginning adjacent the top surface  78  of the ice forming plate  76 , which is cooled by the thermoelectric device  102 ) to the top, which permits air bubbles to escape as the ice is formed layer by layer, resulting in a clear ice piece  98 . 
     As shown in  FIGS. 8-11 , to promote clear ice production, the temperature surrounding the ice tray  70  can also be controlled. As previously described, a thermoelectric device  102  is thermally coupled or otherwise thermally engaged to the bottom surface  80  of the ice forming plate  76  to cool the ice forming plate  76 . In addition to the direct cooling of the ice forming plate  76 , heat may be applied above the water contained in the ice tray  70 , particularly when the ice tray  70  is being rocked, to cyclically expose the top surface of the clear ice pieces  98  being formed. 
     As shown in  FIGS. 8 and 9 , heat may be applied via an air intake conduit  166 , which is operably connected to an interior volume of the housing  168  above the ice tray  70 . The air intake conduit  166  may allow the intake of warmer air  170  from a refrigerated compartment  60  or the ambient surroundings  171 , and each of these sources of air  60 ,  171  provide air  170  which is warmer than the temperature of the ice forming plate  176 . The warmer air  170  may be supplied over the ice tray  70  in a manner which is sufficient to cause agitation of the water retained within the ice tray  70 , facilitating release of air from the water, or may have generally laminar flow which affects the temperature above the ice tray  70 , but does not agitate the water therein. A warm air exhaust conduit  172 , which also communicates with the interior volume  168  of the housing  54 , may also be provided to allow warm air  170  to be circulated through the housing  54 . The other end of the exhaust conduit  172  may communicate with the ambient air  171 , or with a refrigerator compartment  60 . As shown in  FIG. 8 , the warm air exhaust conduit  172  may be located below the intake conduit  166 . To facilitate flow of the air  170 , an air movement device  174  may be coupled to the intake or the exhaust conduits  166 ,  172 . Also as shown in  FIG. 8 , when the housing  54  of the ice maker  52  is located in the door  56  of the appliance  50 , the intake conduit  166  and exhaust conduit  172  may removably engage a corresponding inlet port  176  and outlet port  178  on an interior sidewall  180  of the appliance  50  when the appliance door  56  is closed. 
     Alternatively, the heat may be applied by a heating element (not shown) configured to supply heat to the interior volume  168  of the housing  54  above the ice tray  70 . Applying heat from the top also encourages the formation of clear ice pieces  98  from the bottom up. The heat application may be deactivated when ice begins to form proximate the upper portion of the grid  100 , so that the top portion of the clear ice pieces  98  freezes. 
     Additionally, as shown in  FIGS. 8-11 , to facilitate cooling of the ice forming plate  76 , cold air  182  is supplied to the housing  54  below the bottom surface  80  of the ice forming plate  76 . A cold air inlet  184  is operably connected to an intake duct  186  for the cold air  182 , which is then directed across the bottom surface  80  of the ice forming plate  76 . The cold air  182  is then exhausted on the opposite side of the ice forming plate  76 . 
     As shown in  FIG. 11 , the ice maker is located within a case  190  (or the housing  54 ), and a barrier  192  may be used to seal the cold air  182  to the underside of the ice forming plate  76 , and the warm air  170  to the area above the ice tray  70 . The temperature gradient that is produced by supplying warm air  170  to the top of the ice tray  70  and cold air  182  below the ice tray  70  operates to encourage unidirectional formation of clear ice pieces  98 , from the bottom toward the top, allowing the escape of air bubbles. 
     As shown in  FIGS. 12A-12B , once clear ice pieces are formed, the ice maker  52 , as described herein, harvests the clear ice pieces  98 , expelling the clear ice pieces  98  from the ice tray  70  into the ice storage bin  64 . To expel the ice  98 , the harvest motor  114  is used to rotate the ice tray  70  and the grid  100  approximately 120°. This inverts the ice tray  70  sufficiently that a stop  116 ,  118  extending between the ice forming plate  76  and the rocker frame  110  prevents further movement of the ice forming plate  76  and containment walls  82 . Continued rotation of the harvest motor  114  and arm  154  overcomes the tension of the spring clip  128  linkage, and as shown in  FIG. 12B , the grid  100  is further rotated and twisted through an arc of about 40° while the arm  154  is driven by the harvest motor  114  and the cam pin  150  of the grid  100  slides along the slot  158  from the position shown in  FIG. 12A  to the position shown in  FIG. 12B . This movement inverts and flexes the grid  100 , and allows clear ice pieces  98  formed therein to drop from the grid  100  into an ice bin  64  positioned below the ice maker  52 . 
     Once the clear ice pieces  98  have been dumped into the ice storage bin  64 , the harvest motor  114  is reversed in direction, returning the ice tray  7  to a horizontal position within the rocker frame  110 , which has remained in the neutral position throughout the turning of the harvest motor  114 . Once returned to the horizontal starting position, an additional amount of water can be dispensed into the ice tray  70  to form an additional batch of clear ice pieces. 
       FIG. 13  depicts a control circuit  198  which is used to control the operation of the ice maker  52 . The control circuit  198  is operably coupled to an electrically operated valve  200 , which couples a water supply  202  and the ice maker  52 . The water supply  202  may be a filtered water supply to improve the quality (taste and clarity for example) of clear ice piece  98  made by the ice maker  52 , whether an external filter or one which is built into the refrigerator  50 . The control circuit  198  is also operably coupled to the oscillation motor  112 , which in one embodiment is a reversible pulse-controlled motor. The output drive shaft  136  of the oscillating motor  112  is coupled to the ice maker  52 , as described above. The drive shaft  136  rotates in alternating directions during the freezing of water in the ice maker  52 . The control circuit  198  is also operably connected to the thermoelectric device  102 , such as a Peltier-type thermoelectric cooler in the form of thermoelectric plates. The control circuit  198  is also coupled to the harvest motor  114 , which inverts the ice tray  70  and twists the grid  100  to expel the clear ice pieces  98  into the ice bin  64 . 
     The control circuit  198  includes a microprocessor  204  which receives temperature signals from the ice maker  52  in a conventional manner by one or more thermal sensors (not shown) positioned within the ice maker  52  and operably coupled to the control circuit  198 . The microprocessor  204  is programmed to control the water dispensing valve  200 , the oscillating motor  112 , and the thermoelectric device  114  such that the arc of rotation of the ice tray  70  and the frequency of rotation is controlled to assure that water is transferred from one individual compartment  96  to an adjacent compartment  96  throughout the freezing process at a speed which is harmonically related to the motion of the water in the freezer compartments  96 . 
     The water dispensing valve  200  is actuated by the control circuit  198  to add a predetermined amount of water to the ice tray  70 , such that the ice tray  70  is filled to a specified level. This can be accomplished by controlling either the period of time that the valve  200  is opened to a predetermined flow rate or by providing a flow meter to measure the amount of water dispensed. 
     The controller  198  directs the frequency of oscillation ω to a frequency which is harmonically related to the motion of the water in the compartments  96 , and preferably which is substantially equal to the natural frequency of the motion of the water in the trays  70 , which in one embodiment was about 0.4 to 0.5 cycles per second. The rotational speed of the oscillating motor  112  is inversely related to the width of the individual compartments  96 , as the width of the compartments  96  influences the motion of the water from one compartment to the adjacent compartment. Therefore, adjustments to the width of the ice tray  70  or the number or size of compartments  96  may require an adjustment of the oscillating motor  112  to a new frequency of oscillation ω. 
     The waveform diagram of  FIG. 14  illustrates the amplitude of the waves in the individual compartments  96  versus the frequency of oscillation provided by the oscillating motor  112 . In  FIG. 14  it is seen that the natural frequency of the water provides the highest amplitude. A second harmonic of the frequency provides a similarly high amplitude of water movement. It is most efficient to have the amplitude of water movement at least approximate the natural frequency of the water as it moves from one side of the mold to another. The movement of water from one individual compartment  96  to the adjacent compartment  96  is continued until the thermal sensor positioned in the ice tray  70  at a suitable location and operably coupled to the control circuit  198  indicates that the water in the compartment  96  is frozen. 
     After the freezing process, the voltage supplied to the thermoelectric device  102  may optionally be reversed, to heat the ice forming plate  76  to a temperature above freezing, freeing the clear ice pieces  98  from the top surface  78  of the ice forming plate  76  by melting a portion of the clear ice piece  98  immediately adjacent the top surface  78  of the ice forming plate  76 . This allows for easier harvesting of the clear ice pieces  98 . In the embodiment described herein and depicted in  FIG. 13 , each cycle of freezing and harvesting takes approximately 30 minutes. 
     In another aspect of the ice maker  210 , as shown in  FIGS. 15-33 , an ice maker  120  includes a twist harvest ice maker, which utilizes oscillation during the freezing cycle, variations in thermal conduction of materials, and a cold air  370  flow during the freezing cycle to produce clear ice pieces  236 . The ice maker in  FIGS. 15-33  also has two driving motors  242 ,  244  on one end  246  of the ice maker  210 . The ice maker  210  as shown in  FIGS. 15-33  could also be modified to include, for example, a warm air flow during the freezing cycle, or to include other features described with respect to other aspects or embodiments described herein, such as similar materials of construction or rotation amounts. 
     The ice maker  210  depicted in  FIGS. 15-33  is horizontally suspended within a housing  212 , and located above an ice storage bin (not shown in  FIGS. 15-33 ). The ice maker  210  includes an ice tray  218  having an ice forming plate  220  with a top surface  222  and a bottom surface  224 , and a containment wall  226  extending upwardly around the perimeter of the ice forming plate  220 . A median wall  228  and dividing walls  230  extend orthogonally upward from the top surface  222  of the ice forming plate  220  to define the grid  232 , having individual compartments  234  for the formation of clear ice pieces  236 . 
     As shown in  FIG. 15 , a thermoelectric device  238  is thermally connected to the bottom surface  224  of the ice forming plate  220 , and conductors  240  are operably attached to the thermoelectric device  238  to provide power and a control signal for the operation of the thermoelectric device  238 . Also, as shown in the embodiment depicted in  FIG. 15 , an oscillating motor  242  and a harvest motor  244  are both located proximal to a first end  246  of the ice tray  218 . 
     The ice tray  218  and thermoelectric device  238  are typically disposed within a shroud member  250  having a generally cylindrical shape aligned with the transverse axis of the ice tray  218 . The shroud member  250  is typically an incomplete cylinder, and is open over the top of the ice tray  218 . The shroud  250  includes at least partially closed end walls  252  surrounding the first end  246  of the ice tray  218  and a second end  248  of the ice tray  218 . The shroud member  250  typically abuts the periphery of the containment wall  226  to separate a first air chamber  254  above the ice tray  218  and a second air chamber  256  below the ice tray  218 . The housing  212  further defines the first air chamber  254  above the ice tray  218 . 
     As illustrated in  FIGS. 16-18 , a generally U-shaped bracket  258  extends from the first end  246  of the ice tray  218 , and includes a cross bar  260  and two connecting legs  262 , one at each end of the cross bar  260 . A flange  264  extends rearwardly from the cross bar  260 , and a rounded opening  266  is provided through the center of the cross bar  260 , which, as best shown in  FIGS. 17-18  receives a cylindrical linkage piece  268  with a keyed opening  270  at one end thereof, and a generally rounded opening  272  at the other end thereof. The keyed opening  270  accepts the keyed drive shaft  274  of the harvest motor  244 , and the rounded opening  272  accepts an integral axle  276  extending along the transverse axis from the ice tray  218 . 
     As shown in  FIG. 16 , a harvest arm  278  is disposed between the first end  246  of the ice tray  218  and the cross bar  260  of the bracket  258 . The harvest arm  278 , as best shown in  FIG. 17 , includes a slot  280  for receiving a cam pin  328  formed on the grid  232 , an opening  282  for receiving the cylindrical linkage piece  268  on the opposite end of the harvest arm  278 , and a spring stop  284  adjacent the opening  282 . The harvest arm  278  is biased in a resting position by the spring clip  286 , as shown in  FIGS. 17-18 , which is disposed between the harvest arm  278  and the cross bar  260 , with a first free end  288  of the spring clip  286  seated against the spring stop  284  of the harvest arm  278  and a second free end  290  of the spring clip  286  seated against the flange  264  of the cross bar  260 . 
     Also as shown in  FIG. 16 , the harvest motor  244  is affixed to a frame member  292 , with the keyed drive shaft  274  extending from the harvest motor  244  toward the keyed opening  270  of the cylindrical linkage  268 . When assembled, the keyed drive shaft  274  fits within the keyed opening  270 . The frame member  292  further incorporates a catch  294 , which engages with the ice tray  218  during the harvesting step to halt the rotational movement of the ice forming plate  220  and containment wall  226 . 
       FIGS. 17 and 18  provide additional detail relating to the operable connections of the harvest motor  244  and the oscillating motor  242 . As best shown in  FIG. 17 , the oscillation motor  242  is affixed to a frame member  292  via a mounting  296 . The drive shaft  297  of the oscillation motor  242 , directly or indirectly, drives rotation of the frame member  292  back and forth in an alternating rotary motion during the ice freezing process. As shown in  FIGS. 17 and 20 , the oscillating motor  242  has a motor housing  298  which includes flanges  300  with holes  302  therethrough for mounting of the oscillating motor  242  to a stationary support member (not shown in  FIGS. 15-33 ). 
     During ice freezing, the harvest motor  244  is maintained in a locked position, such that the keyed drive shaft  274  of the harvest motor  244 , which is linked to the ice tray  218 , rotates the ice tray  218  in the same arc that the frame member  292  is rotated by the oscillation motor  242 . As described above, an arc from about 20° to about 40°, and preferably about 30°, is preferred for the oscillation of the ice tray  218  during the ice freezing step. During the harvest step, as further described below, the oscillating motor  242  is stationary, as is the frame member  292 . The harvest motor  244  rotates its keyed drive shaft  274 , which causes the ice tray  218  to be inverted and the ice  236  to be expelled.  FIG. 19  further illustrates the positioning of the oscillating motor  242 , the frame member  292  and the shroud  250 . 
     It is believed that a single motor could be used in place of the oscillating motor  242  and harvest motor  244  with appropriate gearing and/or actuating mechanisms. 
     An ice bin level sensor  30  is also provided, which detects the level of ice  236  in the ice storage bin (not shown in  FIGS. 15-33 ), and provides this information to a controller (not shown in  FIGS. 15-33 ) to determine whether to make additional clear ice pieces  236 . 
     To facilitate air movement, as shown in  FIG. 19 , the shroud  250  has a first rectangular slot  312  therein. As further illustrated in  FIGS. 22-23 and 31 , a second rectangular slot  314  is provided in a corresponding location on the opposing side of the shroud  250 . The rectangular slots  312 ,  314  in the shroud  250  permit air flow through the second chamber  256 , as further described below and as shown in  FIGS. 22-23 and 31 . 
     As shown in  FIGS. 21 and 22 , the shroud  250  encompasses the ice tray  218 , including the ice forming plate  220 , the containment wall  226 , which is preferably formed over an upstanding edge  316  of the ice forming plate  220 , and the grid  232 . The shroud  250  has a semicircular cross sectional area, and abuts the top perimeter of the containment wall  226 . The shroud  250  also encloses the thermoelectric device  102  which cools the ice forming plate  220 , and a heat sink  318  associated therewith. 
     The ice tray  218  is also shown in detail in  FIG. 22 . The ice tray  218  includes the ice forming plate  220 , with upstanding edges  316  around its perimeter, and the containment wall  286  formed around the upstanding edges  316  to create a water-tight barrier around the perimeter of the ice forming plate  220 . 
     The arrangement of the grid  232 , and the materials of construction for the grid  232  as described herein facilitate the “twist release” capability of the ice tray  218 . The features described below allow the grid  232  to be rotated at least partially out of the containment wall  226 , and to be twisted, thereby causing the clear ice pieces  236  to be expelled from the grid  232 . As shown in  FIGS. 23-24 , the grid  232  extends generally orthogonally upward from the top surface  222  of the ice forming plate  220 . A flexible, insulating material  320  may be provided between adjacent walls of the grid  232 . The grid  232  also has a generally raised triangular first end  322 , adjacent the motor  242 ,  244  connections and a generally raised triangular second end  324 , opposite the first end  322 . The grid  232  has a pivot axle  326  extending outwardly from each of the raised triangular ends  322 ,  324 , and not aligned along the transverse axis about which the ice tray  218  is rotated during oscillation. The grid  232  also has a cam pin  328  extending outwardly from each peak of the raised triangular ends  322 ,  324 . The grid  232  may also include edge portions  330 , which are adjacent the side containment walls  226  when the grid  232  is placed therein. As shown in  FIGS. 21 and 23 , the pivot axles  326  are received within generally round apertures  332  on the adjacent containment walls  226 . The cam pin  328  at the first end  322  is received in the slot  280  in the harvest arm  278 , and the cam pin  328  at the second end  324  is received in a socket  334  in the containment wall  226 . 
     The thermoelectric device  102 , as depicted in the embodiment shown in  FIGS. 23 and 26  includes a thermoelectric conductor  336  that is attached to a thermoconductive plate  340  on one side  338  and a heat sink  318  on a second side  342 , having heat sink fins  344 . The thermoconductive plate  340  optionally has openings  346  therein for the thermoelectric conductor  336  to directly contact the ice forming plate  220 . The thermoconductive plate  340 , thermoelectric conductor  336  and heat sink  318  are fastened to the ice tray  218 , along the bottom surface  224  of the ice forming plate  220 , through holes  348  provided on the thermoconductive plate  340  and the heat sink  318 . The thermoelectric conductor  336  transfers heat from the thermoconductive plate  340  to the heat sink  318  during the freezing cycle, as described above. 
     The second end  248  of the containment wall  226  and shroud  250  (the side away from the motors  242 ,  244 ) are shown in  FIG. 25 . A second pivot axle  350  extends outwardly from the containment wall  226 , allowing a rotatable connection with the housing  212 . 
     As shown in  FIGS. 27-30 , the ice tray  218 , partially enclosed within the shroud  250 , is suspended across an interior volume  352  of the housing  312 . The shroud  250  aids in directing the air flow as described below for formation of clear ice pieces  236 . The housing  212 , as shown in  FIG. 27 , includes a barrier  354  to aid in separation of the first air chamber  254  and the second air chamber  256 , so that the second air chamber  256  can be maintained at a temperature that is colder than the first air chamber  254 . The air temperature of the first chamber  254  is preferably at least 10 degrees Fahrenheit warmer than the temperature of the second chamber  256 . 
     When installed in the housing  212 , the shroud member  250  is configured to maintain contact with the barrier  354  as the ice tray  218  is oscillated during ice formation. An air intake duct member  356  having a duct inlet  358  and a duct outlet  360 , with the duct outlet  360  adapted to fit over the surface of the shroud  250  and maintain contact with the shroud  250  as the shroud  250  rotates, is also fitted into the housing  212 . The shaped opening of the duct outlet  260  is sufficiently sized to allow a fluid connection between the duct outlet  260  and the first rectangular slot  312  even as the ice tray  218  and shroud  250  are reciprocally rotated during the freezing cycle. The rectangular slot  312  restricts the amount of air  356  entering the shroud  250 , such that the amount of air  370  remains constant even as the ice tray  218  is rotated. An exhaust duct  362  is optionally provided adjacent the second rectangular opening  314 , to allow air  370  to escape the housing  212 . The exhaust duct  362  has a duct intake  364  which is arranged to allow continuous fluid contact with the second rectangular slot  314  as the ice tray  218  and shroud  250  are rocked during the ice formation stage. The exhaust duct  362  also has a duct outlet  366  which is sufficiently sized to allow the clear ice pieces  236  to fall through the duct outlet  366  and into the ice bin  64  during the harvesting step. 
     An air flow path  368  is created that permits cold air  370  to travel from the duct inlet  358 , to the duct outlet  360 , into the first rectangular slot  312  in the shroud, across the heat sink fins  344 , which are preferably a conductive metallic material, and out of the second rectangular slot  314  in the shroud  250  into the exhaust duct  362 . As shown in  FIG. 30 , baffles  372  may also be provided in the intake duct member  356  to direct the air flow path  368  toward the heat sink fins  344 . The barrier  354  prevents the cold air  370  that is exhausted through the second rectangular slot  314  from reaching the first air chamber  254 . The flow of cold air  370  aids in removing heat from the heat sink  344 . 
     One example of an air flow path  368  enabled by the air intake duct  356  and exhaust duct  362  is shown in  FIGS. 31A-31C . As shown in  FIGS. 31A-31C , as the tray  218  is rocked, the rectangular slots  312 ,  314  in the shroud  250  remain in fluid connection with the air intake duct outlet  360  and the exhaust duct inlet  364 . Therefore, the air flow path  368  is not interrupted by the oscillation of the ice tray  218  during the freezing step. Also, as shown in  FIGS. 32A-32C , as the clear ice pieces  236  are harvested from the ice tray  218 , the clear ice pieces  236  are permitted to fall through the exhaust duct  362  into the ice storage bin. During the harvest cycle as illustrated in  FIGS. 32A-32C , the fluid path  368  for cooling air is not continuous. However, the shroud  250  continues to generally separate the first air chamber  254  from the second air chamber  256 . 
       FIGS. 33A-33D  depict the rotation of the ice tray  218  and the grid  232  during the harvest step. As the harvest motor  244  rotates the ice tray  218  to an inverted position, as shown in  FIG. 33B , the cam pin  328  extending from the second end  324  of the grid  232  travels within the containment wall socket  334  to the position farthest from the ice forming plate  220 . As the harvest motor  244  continues to drive rotation of the arm  278 , the rotation of the ice forming plate  220  is halted by a catch  297 , and the cam pin  328  extending from the first end  322  of the grid  232  continues to travel the length of the slot  280  in the harvest arm  278  away from the ice forming plate  220 . As the length of the slot  280  is longer than the socket  334 , the grid  232  will be twisted, expelling the clear ice pieces  236 . 
     In general, the ice makers  52 ,  210  described herein create clear ice pieces  98 ,  236  through the formation of ice in a bottom-up manner, and by preventing the capture of air bubbles or facilitating their release from the water. The clear ice pieces  98 ,  236  are formed in a bottom-up manner by cooling the ice tray  70 ,  218  from the bottom, with or without the additional benefit of cold air flow to remove heat from the heat sink  104 ,  318 . The use of insulative materials to form the grid  100 ,  232  and containment walls  82 ,  226 , such that the cold temperature of the ice forming plate  76 ,  220  is not transmitted upward through the individual compartments  96 ,  234  for forming ice also aids in freezing the bottom layer of ice first. A warm air flow over the top of the clear ice pieces  98 ,  236  as they are forming can also facilitate the unidirectional freezing. Rocking aids in the formation of clear ice pieces  98 ,  236  in that it causes the release of air bubbles from the liquid as the liquid cascades over the median wall  84 ,  228 , and also in that it encourages the formation of ice in successive thin layers, and, when used in connection with warm air flow, allows exposure of the surface of the clear ice piece  98 ,  236  to the warmer temperature. 
     The ice makers described herein also include features permitting the harvest of clear ice pieces  98 ,  236 , including the harvest motor  114 ,  244 , which at least partially inverts the ice tray  70 ,  218 , and then causes the release and twisting of the grid  100 ,  232  at least partially out of the containment wall  84 ,  226  to expel clear ice pieces  98 ,  236 . The ice forming plate  76 ,  220  and associated thermoelectric device  102 ,  238  can also be used to further facilitate harvest of clear ice pieces  98 ,  236  by reversing polarity to heat the ice forming plate  76 ,  220  and, therefore, heat the very bottom portion of the clear ice pieces  98 ,  236  such that the clear ice pieces  98 ,  236  are easily released from the ice forming plate  76 ,  220  and removed from contacting the ice forming plate  76 ,  220 . 
       FIGS. 34, 35A and 35B  illustrate additional potential embodiments for the ice maker  378 ,  402 . As illustrated by  FIGS. 34 and 35 , alternate arrangements for the ice tray, the cooling mechanism, and the rocking mechanism also permit the formation of clear ice (not shown in  FIGS. 34-35 ) via a rocking mechanism. In each of the additional embodiments, a predetermined volume of water is added to the ice maker  378 ,  402 , and the lower surface  382 ,  404  of the ice maker  378 ,  402  is cooled such that the ice is formed unidirectionally, from the bottom to the top. The rocking motion facilitates formation of the ice in a unidirectional manner, allowing the air to easily escape, resulting in fewer bubbles to negatively affect the clarity of the clear ice piece that is formed. 
     As shown in  FIG. 34 , an ice forming tray  380  may include a central ice forming plate  382 , having a bottom surface  384 , which is cooled by a thermoelectric plate (not shown) having a heat sink  386 , and a top surface  388 , which is adapted to hold water, with reservoirs  390 ,  392  at either end and a containment wall  394  extending upwards around the perimeter of the ice forming plate  382  and reservoirs  390 ,  392 . As shown in  FIG. 34 , the ice maker  378  may also be rocked by alternate means/devices than the rotary oscillating motors previously described. In the embodiment depicted in  FIG. 34 , the ice maker  378  is rocked on a rocking table  396 , with a pivot axle  398  through the middle of the ice forming plate  382 , and at least one actuating mechanism  400  raising and lowering the end of the ice forming plate  382  and the first and second reservoirs  390 ,  392  in sequence. As the tray  380  is rocked, water flows over the central ice forming plate  382  and into a first reservoir  390  on one end. As the tray  380  is rocked in the opposite direction, the water flows over the ice forming plate  382  and into the second reservoir  392  on the other end. As the water is flowing over the ice forming plate  382 , the ice forming plate  382  is being cooled, to facilitate formation of at least one clear ice piece. In this embodiment, a large clear ice piece may be formed in the ice forming plate  382 . Alternatively, a grid or other shaped divider (not shown) may be provided on the ice forming plate  382 , such that water is frozen into the desired shapes on the ice forming plate  382  and water cascades over the divided segments to further release air therefrom. 
     As shown in  FIGS. 35A and 35B , an alternative cooling mechanism and ice forming plate  404  may also be used. Here, an ice forming plate  404  with formed ice wells  406  therein is provided. The wells  406  are capable of containing water for freezing. Each of the wells  406  is defined along its bottom by a bottom surface  408 , which may or may not be flat, and its sides by at least one wall  410  extending upwardly from the bottom surface  408 . Each of the at least one walls  410  includes an interior surface  412 , which is facing the ice well  406  and a top surface  414 . The bottom surface  408  and interior surfaces  412  together make up an ice forming compartment  416 . An insulating material is applied to the upper portion of the ice wells  406  and the top surface of the walls to form an insulating layer  418 . 
     The ice forming plate  404  is preferably formed of a thermally conductive material such as a metallic material, and the insulating layer  418  is preferably an insulator such as a polymeric material. One non-limiting example of a polymeric material suitable for use as an insulator is a polypropylene material. The insulating layer  418  may be adhered to the ice forming plate  404 , molded onto the ice forming plate  404 , mechanically engaged with the ice forming plate  404 , overlayed over the plate  404  without attaching, or secured in other removable or non-removable ways to the ice forming plate  404 . The insulating layer  418  may also be an integral portion of the ice forming plate  76  material. This construction, using an insulating layer  418  proximate the top of the ice wells  406 , facilitates freezing of the clear ice piece  98  from the top surface  78  of the ice forming plate  76  upward. 
     An evaporator element  420  is thermally coupled with the ice forming plate  404 , typically along the outside of the ice wells  406 , opposite the ice forming compartments  416 , and the evaporator element  420  extends along a transverse axis  422  of the ice forming plate  404 . The evaporator element  420  includes a first coil  424  proximate a first end  426  of the ice forming plate  404  and a second coil  428  proximate the second end  403  of the ice forming plate  404 . 
     The ice forming plate  404  and insulating layer  418  as shown in  FIG. 35A  can also be used in an automatic oscillating ice maker  402  as a twisting metal tray, as described above. When so used, the first and second coils  424 ,  428  are configured to permit the evaporator element  420  to flex when a drive body (not shown in  FIG. 35A ) reciprocally rotates the ice forming plate  404 . Alternatively, thermoelectric plates (not shown in  FIG. 35A ) could also be used to cool the ice forming plate  404  from the bottom. In use, a predetermined volume of water is added to the ice wells through a fluid line (not shown in  FIG. 35A ) positioned above the ice forming plate  404 . The bottom surface  408  of the formed ice wells  406  is cooled by the evaporator element  420 , and a drive body (not shown in  FIG. 35A ) causes rotation of the ice forming plate  404  along its transverse axis  422 . The upstanding sides  410  of the formed ice wells  406  contain the water within the formed ice wells  406  as the ice forming plate  404  is rocked, allowing the water to run back and forth across the surface of a clear ice piece (not shown in  FIG. 35A ) as it is formed, resulting in freezing of the clear ice piece from the bottom up. The ice forming plate  404  can then be inverted, and twisted to expel the clear ice pieces. 
     In addition to the multiple configurations described above, as shown in  FIGS. 36-37 , the ice maker  52  according to the present invention may also have a controller  440  which receives feedback information  442  from a sensor  444  regarding the volume of usage of clear ice pieces  98  and uses the feedback  442  to determine an appropriate energy mode for the production of clear ice pieces  98 , for example a high energy mode or a low energy mode. The controller  440  then sends a control signal  450 , instructing a plurality of systems which aid in ice formation  452  whether to operate in the high energy mode or the low energy mode. 
     The sensor  444  may detect, for example, the level of ice  98  in an ice bin  64 , the change in the level of ice  98  in the bin  64  over time, the amount of time that a dispenser  66  has been actuated by a user, and/or when the dispenser has been actuated to determine high and low ice usage time periods. This information  442  is typically transmitted to the controller  440 , which uses the information  442  to determine whether and when to operate the ice maker  52  in a high energy mode or a low energy mode based upon usage parameters or timer periods of usage. This allows the ice maker  52  to dynamically adjust its output based on usage patterns over time, and if certain data are collected, such as the time of day when the most ice  98  is used, the ice maker  52  could operate predictively, producing more ice  98  prior to the heavy usage period. Operating the ice maker  52  in a high energy mode would result in the faster production of ice  98 , but would generally be less efficient than the low energy mode. Operating in the high energy mode would typically be done during peak ice usage times, while low energy mode would be used during low usage time periods. An ice maker  52  having three or more energy modes of varying efficiencies may also be provided, with the controller  440  able to select an energy mode from among the three or more energy modes. 
     One example of an ice maker  52  which could be operated by such a controller  440  would be an ice maker  52  having a plurality of systems  452  which operate to aid in the formation of clear ice pieces  98 , including an oscillating system as described above, a thermoelectric cooling system as described above, a forced air system to circulate warm air as described above, a forced air system to circulate cold air as described above, a forced air system to circulate warm air as described above, a housing  54  which is split into a first air chamber  254  and a second air chamber  256  with a temperature gradient therebetween as described above, and a thermoelectric heating system (to aid in harvesting clear ice pieces) as described above. 
     Operating an ice maker  52  in a high energy mode could include, for example, the use of a particular oscillation setting, a thermoelectric device setting, one or more air circulator settings for use during the ice freezing process, wherein the settings in the high energy mode require more energy, and result in the faster formation of clear ice pieces  98 . The high energy mode could also include using the thermoelectric device  102  to provide a higher temperature to the ice forming plate  76  to cause a faster release of ice pieces  98  during the harvest process and to shorten cycle time for filling and making the ice pieces. 
     The low energy mode could also include a delay in dispensing water into the ice tray, or a delay in harvesting the clear ice pieces  98  from the ice tray  70  as well as lower electronic power (energy) use by the motors  112 ,  114  and thermoelectric devices  102  than the normal mode or high energy mode. Such lower energy use may include no forced air, no requirement to drop the temperature of the second air chamber or ice forming plate, and harvesting can be done with minimal heating to the ice forming plate over a longer period of time, if needed. 
     Additionally, in certain embodiments the controller  440  is able to individually control the different systems, allowing at least one system  452  to be directed to operate in a low energy mode while at least one other system  452  is directed to operate in a high energy mode. 
     It will be understood by one having ordinary skill in the art that construction of the described invention and other components is not limited to any specific material. Other exemplary embodiments of the invention disclosed herein may be formed from a wide variety of materials, unless described otherwise herein. In this specification and the amended claims, the singular forms “a,” “an,” and “the” include plural reference unless the context clearly dictates otherwise. 
     Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range, and any other stated or intervening value in that stated range, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges, and are also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention. 
     It is also important to note that the construction and arrangement of the elements of the invention as shown in the exemplary embodiments is illustrative only. Although only a few embodiments of the present innovations have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts or elements shown as multiple parts may be integrally formed, the operation of the interfaces may be reversed or otherwise varied, the length or width of the structures and/or members or connector or other elements of the system may be varied, the nature or number of adjustment positions provided between the elements may be varied. It should be noted that the elements and/or assemblies of the system may be constructed from any of a wide variety of materials that provide sufficient strength or durability, in any of a wide variety of colors, textures, and combinations. Accordingly, all such modifications are intended to be included within the scope of the present innovations. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the desired and other exemplary embodiments without departing from the spirit of the present innovations. 
     It will be understood that any described processes or steps within described processes may be combined with other disclosed processes or steps to form structures within the scope of the present invention. The exemplary structures and processes disclosed herein are for illustrative purposes and are not to be construed as limiting. 
     It is also to be understood that variations and modifications can be made on the aforementioned structures and methods without departing from the concepts of the present invention, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.