Abstract:
An ice-maker drive mechanism presents a housing having a frontward extending drive for an ice-harvester mechanism and left and right bail arm drive hubs. A bail arm that may drop into an ice bin collecting ice from the ice-maker to sense a height of ice cubes in a the ice bin may be attached to either of the left and right bail arm drive hubs providing a versatile ice-making mechanism that may be used in a variety of refrigerator designs.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application 61/435,008 filed Jan. 21, 2011, hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to ice-making machines for home refrigerators and the like and specifically to an ice-harvest drive used with ice making machines and adapted to be mounted in different orientations and positions within the refrigerator. 
       BACKGROUND OF THE INVENTION 
       [0003]    Household refrigerators commonly include automatic ice-makers located in the freezer compartment. A typical ice-maker provides an ice cube mold positioned to receive water from an electrically operated valve that may open for a predetermined time to fill the mold. The water is allowed to cool in the mold until a temperature sensor attached to the mold detects a predetermined low-temperature point where ice formation is ensured. At this point, the ice is harvested from the mold by an ice-harvest mechanism operated by a drive. The ice-harvesting mechanism may distort the ice mold to remove the “cubes” or may use mechanical ejectors passing into the ice mold to sweep the cubes from the ice mold. 
         [0004]    An ice sensor may be provided to determine when the ice-receiving bin is full. One sensor design incorporated into the ice-harvest drive periodically lowers a bail arm into the ice bin after each harvesting, to gauge the amount of ice in the bin. If the bail arm&#39;s descent is limited by an ice pile of a predetermined height, harvesting is suspended. 
         [0005]    The location of the ice-maker and the accumulating bin may be varied substantially among different models of refrigerators depending, for example, on whether the ice-maker is located in an upper freezer compartment where it may be placed in an elevated position to the rear of the compartment or in a drawer compartment at the lower portion of the refrigerator where it may be moved forward, for example to a side of the compartment, depending on options such as whether there is automatic delivery of ice through the door. The different design constraints on these ice-makers require multiple versions of the ice-harvest drive increasing their costs and complexity. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention provides an improved ice-harvest drive that may be flexibly mounted in multiple locations for use among different refrigerator models. A low profile gear system may be supported by a rear housing wall in cantilevered fashion and provides a bail arm that may be positioned on either side of a housing as may be required for these different mounting locations. 
         [0007]    Specifically, the present invention provides an ice-harvest drive having a housing with a front wall adapted to be positioned adjacent to an ice mold for molding ice cubes, and having right and left sidewalls flanking the front wall. A first rotatable shaft is exposed through the front wall to communicate with the ice mold and a second rotatable shaft extends between the right and left side walls and having first and second ends exposed through each. A reciprocating mechanism communicates with the first rotational shaft to provide reciprocation of the second rotatable shaft with rotation of the first rotatable shaft. A bail arm is attachable to one of the first and second ends and an electric motor held by the housing drives the first rotatable shaft. 
         [0008]    It is thus a feature of at least one embodiment of the invention to provide a flexible mechanism that may be used for a variety of different refrigerator configurations. 
         [0009]    The reciprocating mechanism may be a cam attached to rotate with the first rotatable shaft and a cam follower attached to the second rotatable shaft and communicating with the cam. 
         [0010]    It is thus a feature of at least one embodiment of the invention to provide a compact mechanism that reduces the unsupported length of the ice-maker and hence the torque on the mounting face. 
         [0011]    The housing may provide support journals for the second rotatable shaft at its left and right ends. 
         [0012]    It is thus a feature of at least one embodiment of the invention to provide improved rigidity to the cam follower by stabilizing it with widely separated support points on the second shaft. 
         [0013]    The cam follower and cam may cooperate to lift and drop the bail at least once with every rotation of the first rotatable shaft. 
         [0014]    It is thus a feature of at least one embodiment of the invention to provide a system that positively coordinates operation of the bail arms and the ice-harvesting mechanism. 
         [0015]    The cam may be a radially inwardly facing ledge on a gear. 
         [0016]    It is thus a feature of at least one embodiment of the invention to provide both a more compact mechanism and one which exerts reduced torque on the drive gear axle from the cam action. 
         [0017]    The first and second ends of the second rotatable shaft may include releasable fittings attaching the bail arm releasably to the second rotatable shaft. 
         [0018]    It is thus a feature of at least one embodiment of the invention to allow the ice-maker to be pre-manufactured and stocked with the bail arm easily attached at a later time. 
         [0019]    The releasable fittings may be snap fittings for engaging with the corresponding element of the bail arm. 
         [0020]    It is thus a feature of at least one embodiment of the invention to provide a simple attachment method that may be implemented without tools or additional components. 
         [0021]    Alternatively, the releasable fittings may include a screw and corresponding socket holding the bail arm to one of the first and second end of the second shaft. 
         [0022]    It is thus a feature of at least one embodiment of the invention to provide a low profile attachment method to reduce the overall width of the ice-maker. 
         [0023]    The first and second exposed ends may include key surfaces for engaging corresponding key surfaces in the bail arm locking the two against relative rotation when the key surfaces are engaged. 
         [0024]    It is thus a feature of at least one embodiment of the invention to permit the attachment mechanism for the bail arm to restrain only axial separation with torque being transmitted by the key surfaces. 
         [0025]    The cam follower may be spring loaded to allow movement of the cam follower without corresponding movement of the second rotatable shaft by flexure of the spring. 
         [0026]    It is thus a feature of at least one embodiment of the invention to provide a simple mechanism for preventing damage to the ice-maker if the bail arm is trapped under re-frozen ice. It is another feature of at least one embodiment of the invention to permit the compact drive mechanism to be used without undue risk of damage to the mechanism. 
         [0027]    The spring may be a torsion spring extending along at least a portion of the length of the second shaft. 
         [0028]    It is thus a feature of at least one embodiment of the invention to provide a spring loading mechanism that may employ space along the axis of the second shaft to reduce the profile of the mechanism. 
         [0029]    The ice-harvest drive may further include an electronic sensor element detecting position of the bail arm. 
         [0030]    It is thus a feature of at least one embodiment of the invention to provide a mechanism for detecting a height of accumulated ice in an ice bin associated with the ice-maker. 
         [0031]    The housing may include a detent element engaging a corresponding element on the second shaft to releasably hold the second shaft in an elevated position when the bail arm is lifted beyond a predetermined point. 
         [0032]    It is thus a feature of at least one embodiment of the invention to permit the bail arm to act as a switch for disabling the ice-maker. 
         [0033]    The electronic sensor element is selected from the group consisting of a mechanical electrical switch and a Hall Effect electrical switch. 
         [0034]    It is thus a feature of at least one embodiment of the invention to provide an ice-maker that can flexibly work with low-cost mechanical switches and Hall Effect switches resistant to contamination. 
         [0035]    The ice-harvest drive may further include an electronic sensor element detecting a rotational position of the rotatable shaft. 
         [0036]    It is thus a feature of at least one embodiment of the invention to provide a signal allowing interpretation of movement of the bail arm and for control of the ice making process. 
         [0037]    The ice-harvest drive may further provide a rear wall opposite the front wall extending between the left and right walls providing attachment points for attaching the housing to support structure. 
         [0038]    It is thus a feature of at least one embodiment of the invention to provide a mounting point free from interference with the bail arms and first rotatable shaft. 
         [0039]    The attachment point is a set of threaded holes. 
         [0040]    It is thus a feature of at least one embodiment of the invention to provide an attachment point consistent with close abutment of the ice-maker to a supporting structure for reduced cantilever torque. 
         [0041]    The electric motor is a DC permanent magnet motor. 
         [0042]    It is thus a feature of at least one embodiment of the invention to permit the use of a low-voltage motor having reduced shock hazard, heating, and size with respect to AC gear motors. 
         [0043]    The ice-harvest drive may further include a resistor for limiting stall current to the DC permanent magnet motor. 
         [0044]    It is thus a feature of at least one embodiment of the invention to provide a simple torque limiting mechanism for preventing damage to the ice making components in the event of blockage of the ice-harvesting mechanism. 
         [0045]    The motor may communicate with the first rotatable shaft via a combination of spur gears one of which is driven by a worm gear attached to the motor. 
         [0046]    It is thus a feature of at least one embodiment of the invention to revise a low profile drive mechanism in which the axis of the motor may lie perpendicular to the separation of the front and back walls of the housing. 
         [0047]    Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0048]      FIG. 1  is a top plan view of an ice-maker suitable for use with the ice making mechanism of the present invention showing a bail arm for detecting the height of harvested ice cubes on a left side of the drive unit; 
           [0049]      FIG. 2  is a front elevational view of the ice-making mechanism of  FIG. 1 ; 
           [0050]      FIG. 3  is a front perspective view of the ice-making mechanism showing the bail arm on the right side of the drive unit; 
           [0051]      FIG. 4  is a rear perspective view of the ice-making mechanism showing an exposed end of a bail arm shaft keyed for screw attachment of the bail arm; 
           [0052]      FIG. 5  is an exploded diagram of the drive mechanism of the present invention showing an internal bail arm shaft, supported at opposite ends on the left and right side of the housing; 
           [0053]      FIG. 6  is fragmentary front perspective view of an internal output gear and cam communicating with a cam follower on the bail arm shaft having exposed ends for screw attachment of the bail arms; 
           [0054]      FIG. 7  is a fragmentary view an alternative embodiment of the exposed ends of the bail arm shaft providing snap attachment; 
           [0055]      FIG. 8  is a side elevational view of the output gear of  FIG. 6  showing a home cam on a front surface of the output gear as may trigger a switch to sense a home position of the output gear; 
           [0056]      FIG. 9  is a side elevational view of a switch cam attached to the bail arm shaft as may trigger a switch to sense position of the bail arm and showing a mechanical detent for holding the bail arm in the raised position; 
           [0057]      FIGS. 10   a  and  10   b  are rear and front surfaces of the output gear showing the home cam and the bail arm elevating the cam surface. 
       
    
    
       [0058]    Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0059]    Referring now to  FIGS. 1 and 2 , an ice-maker  10  may include an ice mold  12  for receiving water and molding it into frozen ice “cubes”  17  of predetermined but arbitrary shape. The ice mold  12  is adjacent to an ice-harvest drive  14  operating to power a harvesting mechanism to remove cubes from the mold when they are frozen, for example, a harvesting mechanism providing inversion and distortion of the ice mold  12  or a harvesting mechanism using a cube remover comb (not shown) of a type known in the art. The ice mold  12  may be positioned above an ice storage bin  15  for receiving cubes  17  therein when the latter are ejected from the ice mold  12 . 
         [0060]    The ice-harvest drive  14  may have a coupling  16  extending along a horizontal axis  29  and exposed at a front wall  18  of a housing  20  of the ice-harvest drive  14  to engage the ice-harvest mechanism (for example the mold  12  or a comb). Generally the coupling  16  will rotate about the horizontal axis  29 . 
         [0061]    The left wall  22  and right wall  24  of the housing  20 , flanking the front wall  18 , may each present an exposed hub  36  extending outward along a horizontal axis  32  perpendicular to axis  29  from the left wall  22  and right wall  24  respectively. Either one of the hubs  36  may receive one end of a bail arm  30  (shown on the right side only in  FIG. 1 ), the latter which may pivot about the horizontal axis  32  between three positions. At the first substantially horizontal position  27   a  (shown in dotted lines), the bail arm  30  is retained by an internal detent (to be described below) to deactivate the ice-maker  10 . At a second intermediate position  27   b  (also shown in dotted lines), a distal end of the bail arm  30  as held away from a bottom of the ice storage bin  15  also deactivates the ice-maker  10 . At a third lowered position  27   c,  the distal end of the bail arm  30  is proximate to the bottom of the ice storage bin indicating that more ice may be made and allowing continued function of the ice-maker  10 . 
         [0062]    Referring now to  FIGS. 3 ,  4  and  5 , rotating hubs  36  exposed at the left wall  22  and right wall  24  of the housing  20  may provide key surfaces, in this case, in the form of a hexagonal radial periphery. The bail arm  30  may have a corresponding key socket  39  (shown in  FIG. 5 ) inter-fitting with the key surfaces of the rotating hubs  36  and receiving the hub  36  to be rotationally locked thereto. The bail arm  30  may be attached to the rotatable hub  36 , after engagement of the hub  36  and key socket  39 , by means of a self tapping screw  41  fitting through a hole  31  in the bail arm  30  at the rotatable hub  36  to be threadably engaged with a corresponding hole  40  in the hub  36  (visible in  FIG. 4 ) extending along the axis  32 . The screw  41  retains the bail arm  30  attached to the rotatable hub  36  under the screw head so that they rotate in unison. 
         [0063]    Referring now to  FIG. 7 , in an alternative embodiment the hubs  36  may include snap elements  33 , in this case parallel blades extending along axis  32  having outwardly extending hook elements that may be received within a rectangular opening  35  in the bail arm  30 . A snap engagement is provided by an inward flexing of the parallel blades to allow the hook elements to fit within the rectangular opening  35  and a subsequent outward springing of the parallel blades once the hook elements clear the rectangular opening  35 , whereupon the hook elements engage the bail arm  30  on the far side of the rectangular opening  35 . In this case a key socket  39  is not required, the torque-resisting function being provided by the blades of the snap elements  33 . It will be appreciated that other methods of attaching the bail arm  30  to the rotatable hub  36  may be used including, for example, ultrasonic staking, adhesive, rivets or the like. 
         [0064]    As noted, a rotatable hub  36  is exposed at both the left wall  22  and right wall  24  of the housing  20  so that the bail arm  30  may be attached to either side of the housing  20 . In one embodiment, the opposite ends of the bail arm  30  may be mirror images so that a single bail arm  30  may be used when attached on either side of the housing  20  for similar extension from the housing forward over the ice bin  15 . In this case, identical key socket  39  and hole  31  are formed in both ends of the bail arm  30  albeit on opposite sides. 
         [0065]    Alternatively as shown in  FIG. 5 , the bail arm  30  may be customized for the particular side of the housing  20  to which it will be attached and its cantilevered end differentiated to provide, for example, additional weight to ensure that the bail arm  30  will swing downward into the bin  15  against the frictional resistance of any attached mechanism. 
         [0066]    Referring now to  FIG. 5 , the two rotatable hubs  36  may be joined by a common shaft  42  extending along the axis  32  therebetween and passing through the housing  20 . The common shaft  42  may include journal portions  43  that may be supported by corresponding bearing surfaces  23  formed in the housing  20  so that the shaft  42  is supported at both ends to better resist off-axis torque. 
         [0067]    The shaft  42  may support a torsion spring  45  being a wire form extending along the shaft  42  parallel to the axis  32  with inwardly bent ends effectively anchored against rotation near the journal areas  43 . A center of the torsion spring  45  is bent outward then back to provide a cam follower  44  that may extend radially from the shaft  42  forward and perpendicular to axis  32  to be received by a cam surface  46  on a rear surface of an output gear  48 . The cam follower  44  and cam surface  46  interact so that rotation of the output gear  48  raises and drops the cam follower  44 , and thus rotates the shaft  42  and the bail arm  30  appropriately during operation of the ice-maker  10 . 
         [0068]    Referring also to  FIGS. 6 and 10   a , the cam surface  46  may provide a ledge projecting rearward along axis  29  and presenting a surface facing inward toward axis  29 , separated from the axis  29  at different radii. The cam follower  44  provided by the torsion spring  45  may rest upon the ledge of the cam surface  46  as biased thereagainst by the weight of the cantilevered bail arm  30 . The torsion spring  45  spring loads the cam follower  44  so that if the bail arm  30  and hence the shaft  42  is obstructed in some manner, the cam follower  44  may flex upward as indicated by arrow  47  to permit continued motion of the output gear  48 . The upward flexing of the cam surface  46  twists the torsion spring  45  along its wire elements extending along axis  32 , as constrained by support blocks  51  projecting from the shaft  42 , and bent ends of the torsion spring  45  near the hubs  36  which pass under the shaft  42 . 
         [0069]    Referring still to  FIGS. 5 ,  6  and also to  FIG. 9 , one end of the shaft  42  may also support a switch cam  37  and detent arm  34  projecting radially forward from the shaft  42  and axis  32 . The distal end of the switch cam  37  may press in on a switch operator  58   a  when the bail arm  30  is in a lowered position and may release the switch operator  58   a  (as shown in  FIG. 9 ) when the bail arm  30  is raised. The switch operator  58   a  may be a flexible strip of metal supported at one end by a printed circuit board  61  (affixed to the housing  20 ) and extending in cantilevered fashion over a tactile electrical switch  60   a  also attached to the printed circuit board  61 . 
         [0070]    Referring again to  FIG. 5 , the output gear  48  provides on its front surface the coupling  16  that extends through a bearing opening  19  in the front wall  18  of the housing  20  to operate the ice-harvesting mechanism. 
         [0071]    In addition, the front surface of the output gear  48 , as shown in  FIGS. 8 and 10   b , also supports a home cam  49  that provides a surface extending parallel to axis  29  at one angular location about the axis  29  designating a home rotational position of the output gear  48 . Referring to  FIG. 8  at the home rotational position of the output gear  48 , the home cam  49  will press inward on switch operator  58   b  (similar to switch operator  58   a ) which may activate tactile switch  60   b  providing an indication of the rotational position of the output gear  48 . 
         [0072]    The electrical signals from the switches  60   a  and  60   b  will generally provide three types of information: (1) information about how much ice is in the ice bin  15  (shown in  FIG. 2 ), (2) information about whether the consumer wishes to stop ice-making by the ice-maker  10 , and (3) information about possible immobilization of the bail arm  30  by ice, each which will be described below. 
         [0073]    Referring again to  FIG. 5 , output gear  48  may be driven by a gear train  50  of multiple spur gears driven by a motor  52 , the gear train  50  providing an increase in torque and the reduction in rotation speed of the motor  52  to turn the output gear  48  at about two revolutions per minute. Motor  52  may be a standard low voltage permanent magnet DC motor  54  and communicate with the gear train  50  by means of a worm gear  56  communicating with an outer toothed periphery of one of the gears of the gear train  50 . The worm gear  56  may extend generally perpendicular to the axis of the gears of the gear train  50  and the axis  29  of the output gear  48  to reduce the total housing thickness. In the event that the output coupling  16  is blocked, the motor  54  is controllably torque limited by the resistance of its internal windings as tuned by a series resistance  55  in series with windings of the motor  54 . 
         [0074]    Referring now to  FIGS. 10   a  and  10   b , during each ice making cycle, generally the output gear  48  will begin in the home position as detected by the home cam  49 . This position will locate the output coupling  16  to allow filling of the ice mold  12  with water and freezing of the water into ice cubes. 
         [0075]    Once the water has frozen as indicated by a timer or a thermal sensor, the motor  54  may be activated to rotate the output gear  48  from the home position. The first 270 degrees of rotation of the output gear  48  provides for a harvesting of the ice cubes  17  from the ice mold  12  where the ice cubes  17  are released from the ice mold  12  to drop into the bin  15 . 
         [0076]    At the conclusion of this 360 degrees of rotation, the output gear will align the cam surface  46  so that its greatest radius from axis  29  is aligned with the cam follower  44  allowing the bail arm  30  to drop into the ice bin  15  (shown in  FIG. 1 ) to check the height of the accumulated ice cubes  17 . If at this time when the bail arm  30  is allowed to drop by the cam surface  46 , the bail arm  30  does not drop sufficiently to activate switch  60   a  (shown in  FIG. 9 ) it may be presumed that the ice bin  15  is full. Further filling of the ice cube tray with water for creating additional ice cubes may be stopped until the ice level faults sufficiently to allow full descent of the bail arm  30 , although rotations of the output gear  48  are allowed to permit additional height sensing by the bail arm  30 . 
         [0077]    It will be understood that by this circuitry, elevation of the bail arm  30  can be used by the consumer to turn off the ice-maker  10 . Referring to  FIG. 9 , this latter feature may be facilitated by allowing the detent arm  34  to engage a flexible catch  53  molded into the housing  20  that may releasably retain the bail arm  30  in the elevated position of  FIG. 9  against the weight of the bail arm  30  until released by the consumer by downward. 
         [0078]    When the output gear  48  returns to the home position, if the bail arm  30  is trapped downward by the ice cubes  17 , the switch cam  37  will be retained in its engagement with the switch operator  58   a  of  FIG. 9  instead of releasing the switch cam  37  as would occur during normal operation. This switch configuration indicates an error condition that may be used by refrigerator logic to also stop further filling of the ice cube trays and effectively to deactivate the ice-maker  10  until the bail arm  30  is freed. 
         [0079]    It will be appreciated that the tactile switches  60   a  and  60   b  may be replaced with other switch types, for example, with Hall Effect sensors triggered by magnets embedded in the cam  37  or  49 . It will also be appreciated that other mechanisms such as a crank arm, planetary gear, slot and pin mechanism, and the like may also be used. 
         [0080]    Various features of the invention are set forth in the following claims. It should be understood that the invention is not limited in its application to the details of construction and arrangements of the components set forth herein. The invention is capable of other embodiments and of being practiced or carried out in various ways. Variations and modifications of the foregoing are within the scope of the present invention. It also understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention.