Abstract:
A method of controlling a dispenser duct door, including positioning an upper side of the door, in a closed position, in a door-opening direction, and rotating a bottom end of the door to a partially open position vertically under the upper side of the door in response to an opening signal. The bottom end of the door is rotated further in the door-opening direction in response to ice hitting a rear of the door and is returned to the partially open position. After a predetermined delay, the bottom end of the door is returned to the closed position.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to refrigerator dispenser doors, and, more particularly, to doors for dispenser ducts for icemakers. 
     Consumer ice dispensers that dispense through a freezer compartment door typically have a duct door that prevents or restricts warm moist air from entering the refrigerated compartment. The door is held in its sealing position by a bias spring. When either crushed or cubed ice is requested by the user, the duct door is fully opened by several different mechanisms initiated by pressure from a receptacle, usually a drinking glass. When the glass is sufficiently full the user removes the pressure from the mechanisms. A “time delay” mechanism holds the duct door open for a few seconds to allow any ice pieces which are “on their way” to be discharged rather than accumulating in undesirable places in the dispenser system. After this brief delay the bias springs close and seal the duct doors. A main problem with these arrangements has been poor control of crushed ice spray. 
     BRIEF SUMMARY OF THE INVENTION 
     It would be desirable to open and close the door with improved control of crushed ice spray. In one embodiment the door is biased toward a first closed position by a first magnetic force. A second magnetic force is then applied to urge the door to a second partially open position. The door is yieldably maintained in the second position until contacted by a dispensed item, such as crushed ice. The door is then moved to a third position more open than the second position in response to the dispensed item contacting the door. The second magnetic force is then released and the door is closed in response to the first magnetic force. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded front upper right perspective view of an ice dispenser duct door mechanism; 
     FIG. 2 is a front elevational view of an ice dispenser duct door mechanism, in partial cutaway; 
     FIG. 3 is a bottom view taken along line  3 — 3  of FIG. 2; 
     FIG. 4 is a cross-sectional view taken along line  4 — 4  of FIGS. 2 and 3; and 
     FIG. 5 is a perspective view taken along line  5 — 5  of FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 is an exploded view of one embodiment of a duct door mechanism  10  is shown. Mechanism  10  includes a recess housing  12 , a front section  14 , a left section  16 , a right section  18 , a water supply tube  20  and a door assembly  22 . Duct door assembly  22  includes a duct door  24 . As will be described below, duct door  24  is not forcibly opened to its extreme. Instead, duct door  24  is opened on “initiation” a minimum amount in the order of ¼ inch. Duct door  24  is free to open further to pass larger ice pieces but returns by gravity to this minimum opening. In this “gravity pendulum” manner door  24  absorbs ice momentum slowing ice down for gentler deliver to the glass. The delivery accuracy is helped by a rigid funnel  26  that completely surrounds a duct outlet  28  and then funnels the opening from the diameter of outlet  28  down to within the diameter of the rim of a majority of glasses. To further help accuracy, funnel  26  moves with the glass, thus taking away the relative motion of some systems. 
     Mechanism  10  uses permanent magnets  30  and  32  to pull duct door  24  closed from a “minimum opening” position. Then an electromagnet  34  is used to counteract magnets  30  and  32  and open door  24  to the minimum opening and hold door  24  open for a few second “delay” at the end. When DC power is removed from electromagnet  34  permanent magnets  30  and  32  close and seal door  24 . 
     Housing or “recess”  12  has a wall  13  which wraps around the side and top of mechanism  10  to cooperate to define a refrigerator frontal recess (not shown) for dispensing ice and water from a refrigerator (not shown) or the like. Permanent magnets  30  and  32  are ceramic magnets connected by steel bar  36  forming a “horseshoe” or “C” shaped magnet with hooked ends  33  and  35 . Magnets  30  and  32  are attracted to the “horseshoe” or “C” shaped iron core  34 ,  36  of the electromagnet. That is electromagnet core  34 ,  36  completes an electromagnetic circuit for permanent magnets  30  and  32 . 
     Recess  12  is shown as a cut cross-section with a molded in entrance  38  for drinking water supply tube  20  and a terminal end  40  of an ice duct  42  through a door opening  44  of recess  12 . Door opening  44  is selectively sealed and unsealed by door  24 . 
     Iron core  36  of electromagnet  34  reaches around door  24  to be adjacent to permanent magnets  30  and  32  of door assembly  22 . Hooked ends  33  and  35  are housed in pockets  46  molded into recess  12 . Core  36  is made in two pieces or arms  48  and  50  to facilitate assembly through electromagnet  34 , shown as its winding bobbin. Left and right sections  16  and  18  slide over arms  48  and  50  trapping an actuation switch  52  and providing journal bearings  54  and  56  for two pivots  58  and  60  molded onto funnel  26  of front section  14 . Door  24  is pivoted on two pivot pins  62  and  64 . Door pivot pins  62  and  64  engage two matching openings  66  and  68  provided in rear upper corners of funnel  26 . When assembled, triangular shaped faces  70  and  72  of left and right sections  16  and  18  slide up inclined ramps  74  molded into recess  12  and position duct door  24  to seal terminal end  40  of ice duct  42  through door opening  44 . 
     FIG. 2 is a front elevational view of mechanism  10 . FIG. 2 is in partial cutaway consistent with FIG.  1 . Funnel  26  wraps around a lower portion  76  of door opening  44  and extends forwardly from opening  44 . An activation lever tongue  78  is attached to a bottom center rear  80  of funnel  26  and extends downwardly and forwardly from funnel  26  to be contacted by a glass (not shown) during use. In practice a glass would contact a lower edge  82  of tongue  78  and push edge  82  rearwardly. Since funnel  26  in pivotally mounted by pivots  58  and  60  in bearings  54  and  56 , funnel  26  also rotates rearwardly and contacts actuation switch  52  to cause electromagnet  34  to be activated and door  24  opened. This allows the glass to move with funnel  26  to eliminate relative movement between the glass and funnel  26 , which might otherwise cause ice to miss the glass. Funnel  26  in one embodiment includes integral curved sides  84  and  86  to allow unimpaired vision of dispensed ice while still providing sufficient structural strength. 
     FIG. 3 is a bottom view taken along line  3 — 3  of FIG. 2, and therefor is also in partial cutaway. Tongue  78  is seen attached to funnel  26  as previously described. Curved sides  84 ,  86 , and tongue  78  define an dispensing opening  90 , through which dispensed ice passes to the glass. Opening  90  is generally circular and of smaller diameter than opening  44 . 
     FIG. 4 is a side cross sectional view taken along lines  4 — 4  of FIGS. 2 and 3. A rear cover  92  of assembly  22  has a concave flexible inner face or center region  94 . Assembly  22  includes an insulation layer  96  sandwiched between flexible rear cover  92  and a hard plastic front cover  98 . 
     FIG. 5 is a rear perspective view of assembly  22 . Rear cover  92  has a flexible inner face  94  and a flexible perimeter seal lip  100 . Magnets  30  and  32  fit in molded in pockets  102  and  104  in two arms  106  and  108  of cover  98 . Magnets  30  and  32  are retained by a backing bar  110  extending between arms  106  and  108 . 
     Door  24  is attached at an upper side  112  to pivots  62  and  64  to allow a bottom end  114  of door  24  to swing open. Upper side  112  can be tilted forwardly (outwardly) relative to bottom end  114  so that the gravity neutral position of door  24  is slightly open. Left magnet  30  and right magnet  32  can be provided to hold door  24  shut against the force of gravity tending to open it. This allows falling crushed ice behind door  24  to rapidly open door  24  and to fully empty before magnets  30  and  32  pull door  24  back up shut. 
     When the user pushes a glass against edge  82 , funnel  26  pivots backward around bearings  54  and  56 , trips actuation switch  52 , and raises duct door  24  slightly. The small relative motion between door  24  and recess  12  amplifies glass pressure to break any sugar or ice bonds that may have formed between the door  24  and recess  12 . Breaking sugar or ice bonds helps insure that the small magnetic repulsive forces of electromagnet  34  are able to reliably open the door to its “minimum” every time. A heater (not shown) can be provided in a peripheral region of the door  24 , if desired. 
     The door  24  is biased toward the closed position of FIG. 4 by a first magnetic force of magnets  30  and  32 . When a glass (not shown) is pushed against edge  82 , tongue  78  is pushed rearward to activate actuation switch  52 . This activation of button  52  causes electricity to be applied to electromagnet  34  to apply a second magnetic force opposed to and greater than the first magnetic force to urge the door  24  to a second partially open position. So long as the glass pushes tongue  78 , this second magnetic force continues to be applied, thus maintaining the door yieldably in the second position until contacted by a dispensed item (not shown.) When contacted by a dispensed item, such as crushed ice or an ice cube, door  24  is knocked to a third position more open than the second. Rear cover  92  is flexible to more quietly absorb this impact on door  24 . However, gravity causes door  24  to quickly return to the second position following such impact. When the user releases pressure of the glass on tongue  78 , the second magnetic force is released and the first magnetic force of magnets  30  and  32  closes door  24 , preferably after a delay. In a particular embodiment, deactivation of actuation switch  52  reverses electromagnet  34  to reverse the resultant electromagnetic force and attract magnets  30 ,  32  to close door  24  when tongue  78  is released. 
     While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.