Patent Publication Number: US-6209340-B1

Title: Ice clearing structure for ice makers

Description:
This application claims benefit of Provisional Ser. No. 60/111,163, filed Dec. 7, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to ice makers and more specifically to structures therein for clearing ice from the evaporator. 
     2. Background 
     Ice makers are well known in the art and typically make ice by flowing water over an electrically cooled evaporator. The water that is not frozen onto the evaporator is caught by a drain pan and recycled over the evaporator. When an ice sheet of a sufficient thickness has formed thereon, a hot gas defrost cycle is started causing the ice to melt partially around the exterior surface thereof whereupon its adhesion to the evaporator surface is lessened. The ice can then fall from the evaporator and into an ice bin positioned there below. However, a problem can occur where the ice sheet does not fall completely out of the evaporator or contacts and rests on the water drain pan and leans against the evaporator. Subsequent ice making cycles can result in an unwanted build up of ice on the evaporator and shut down of the ice maker. 
     Various strategies have been employed to insure that the ice sheet is fully and positively removed from the evaporator. A separate active mechanism is known to push the ice from the evaporator. However, such an approach adds further components resulting in an increased cost and a decreased reliability. The evaporator can also be maintained at an angle that is more conducive to the ice falling, i.e. at an angle between the vertical and the horizontal. However, such an angular positioning can result in an undesirable portion of internal ice maker volume being dedicated to the evaporator rather than ice storage and can negatively impact uniform cube formation. Accordingly, it would very desirable to have an ice removing structure that does not increase cost or complexity and that is space efficient. 
     SUMMARY OF THE INVENTION 
     The present invention concerns a modified water drain pan for use in an ice maker. The drain pan is positioned below a vertically oriented evaporator and includes a front lip for receiving run off water from the evaporator during the ice making cycle. A plurality of spaced apart ice removing projections are formed integrally into and extend upward from and along the drain pan front lip. The ice moving projections serve to define a V-shaped groove along and adjacent the front lip. 
     In operation, the drain pan of the present invention is positioned to receive the drain water during the ice making cycle as it flows over the evaporator. When the ice is harvested the ice sheet falls from the evaporator such that a bottom edge thereof lands within the V-shaped groove. A bottom exterior corner edge of the ice sheet contacts a front surface of the V-shaped groove wherein the force applied there against by the weight of the entire sheet causes the sheet to rotate about an imaginary axis extending within and along that groove. As a result thereof, the top of the ice sheet tips in a forward direction away from the evaporator where upon it falls into the ice bin below. Thus, the V-shaped groove causes a movement of the ice sheet powered by its own weight wherein it is moved positively away from the evaporator. Thus, the drain pan of the present invention prevents the ice sheet from being able to rest thereon and lean against the evaporator. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     A better understanding of the structure and features of the present invention and of the operation and objects and advantages thereof can be had by reference to the following detailed description which refers to the following figures, wherein: 
     FIG. 1 shows a perspective view of the drain pan of the present invention. 
     FIG. 2 shows a perspective view of the present invention as positioned within an ice maker below an evaporator. 
     FIG. 3 shows a cross-sectional view along lines  3 — 3  of FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The drain pan of the present invention is seen in the various figures and generally indicated by the numeral  10 . Drain pan  10  includes sidewalls  12  and a bottom surface  14  defining and interior water reservoir volume  16 . Bottom surface  14  includes a drain orifice  18 . Drain pan  10  also includes a perimeter horizontal edge flange  20  having a front portion  20   a.  A plurality of ice moving structures  22  are integral with and extend upward and from drain pan  10  along front edge  20   a.  Those of skill will understand that pan  10  is formed from a sheet of plastic such as through a vacuum molding process. Thus, as seen in FIG. 3, it will be understood that structures  22  are hollow and formed essentially from or into pan  10 . Structures  22  define a V-shaped groove  26  having a bottom point  27  at the junction of a first angular surface  26   a  and a second angular surface  26   b.  Structures  22  also include a third angular surface  28  that together with surface  26   a  define an apex point  30 . Fourth angular surfaces  32  define with angular surfaces  26   b  second minor apex points  34 . Structures  22  also include vertical sidewalls  36  on either side thereof. Angled water flow surfaces  38  extend between structures  22 . 
     As seen in FIG. 2, drain pan  10  is positioned below an evaporator  40 . Evaporator  40 , as is known in the art, includes a plurality of ice forming pockets  42  defined by horizontal dividers  44  and vertical dividers  46 . As is also known, horizontal dividers  44  are angled in a downward direction to facilitate the falling of the ice sheet from evaporator  40 . An ice harvest bar  47 , as is known in the art, is pivotally secured to evaporator  40  for opening into an open position by movement in the direction of arrow A. As is understood, harvest bar  47  opens by the ice sheet falling therefrom. Harvest bar  47  operates a switch, not shown, that indicates such ice sheet movement so that a subsequent ice making cycle can be started. As is well known in the art, the ice sheet is formed in evaporator  40  by a flow of water over the surface thereof. The water originates from a water distribution tube, not shown, located at the top of evaporator  40  and proceeds over the surface as evaporator  40  is cooled by a refrigeration system. Thus, water that is not frozen flows off evaporator  40  and is caught by edge  20   a  of drain pan  10  to flow along surfaces  38  into water reservoir area  16 . Water is then pumped from reservoir  16  back over evaporator  40  until a sheet of ice of sufficient thickness has formed thereon. The various refrigeration and water pumping and distribution components and control systems and structures necessary to carry out the above described ice formation process are very well understood, and are not shown herein to facilitate a clear understanding and view of the present invention. 
     The positive ice clearing operation of the present invention can be understood by reference to FIG. 3 where an ice sheet  48  is shown in dashed outline. Ice sheet  48  first slides under the force of gravity from evaporator  40  after it has been loosened therefrom by, for example, a hot gas defrost cycle. A bottom end  50  of sheet  48  can then be understood to fall into V-shaped groove  26 . In particular, angled surface  26   a  can be contacted by end  50  thereby directing end  50  into angled surface  26   b.  Contact between a forward edge  52  and surface  26   b  will cause sheet  48  to rotate about an axis extending along groove  26  resulting in the movement of the top end  54  thereof as indicated by arrow B. As a result thereof, sheet  48  falls into an ice receiving bin located below pan  10 . It is important to insure such rotation that the distance D between apex point  30  and bottom point  27  be less than the width W of Sheet  48 .