Abstract:
A motorized damper door assembly for use in freezing temperature applications includes a damper frame, a damper door having, a mounting portion rotatably mounted to the frame, and a seal member having a vertically extending moisture barrier adjacent the mounting portion. The door mounting portion and the moisture barrier together form a reservoir inside the door mounting portion to prevent moisture from seeping directly into the motor housing below the door mounting portion. Consequently, as moisture accumulation in the motor housing is avoided, associated damper jamming and impaired performance issues are also avoided.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates generally to motorized dampers, and, more particularly, to motorized dampers for use in freezing temperature conditions.  
           [0002]    At least one type of motorized damper includes a damper door rotatably mounted in a damper frame having an opening therethrough. An electric motor is coupled to the damper door and positions the damper door in desired positions relative to the damper frame opening. When located in, for example, an air flow path, air flow through the damper can be regulated by positioning the damper door to, for example, a fully closed position substantially preventing airflow through the damper frame opening, a fully open position where airflow through the damper frame opening is substantially unimpeded, and intermediate positions between the fully open and closed positions.  
           [0003]    In certain applications, this type of damper is vulnerable to jamming in cold temperature conditions. For example, refrigerators typically employ one or more of these dampers to regulate airflow between a fresh food compartment and a freezer compartment. The damper is opened to introduce cold air from the freezer compartment into the fresh food compartment to regulate fresh food compartment temperature. The temperature differential between the fresh food compartments and humidity in one or both of the compartments can cause moisture to accumulate on the damper door. The moisture runs down the door and permeates a seal between the damper door and the damper frame, and eventually into the motor housing where it may collect on cam surfaces, gears, and other moving parts of the motor mechanism. Freezing temperatures therefore create ice on the motor mechanism that can jam the damper door, or at least impair its ability to be positioned properly. To meet stringent energy and performance requirements, it is important that the dampers be positioned reliably and accurately.  
         BRIEF SUMMARY OF THE INVENTION  
         [0004]    In an exemplary embodiment, a motorized damper door assembly for use in freezing temperature applications includes a damper frame, a damper door having a mounting portion rotatably mounted to the frame, and a seal member having a vertically extending moisture barrier adjacent the mounting portion. The door mounting portion and the moisture barrier together form a reservoir inside the door mounting portion to prevent moisture from seeping directly into the motor housing below the door mounting portion. Rather, moisture can enter the motor housing only after rising to the level exceeding the height of the moisture barrier.  
           [0005]    With strategic selection of moisture barrier height, moisture entry into the motor housing is practically eliminated. Consequently, as moisture accumulation in the motor housing is avoided, associated damper jamming and impaired performance issues are also avoided. A reliable and cost effective motorized damper assembly is therefore provided that may be used in low temperature conditions and environments, such as in a refrigerator, to more capably meet applicable energy and performance objectives. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    [0006]FIG. 1 is a perspective view of a sealed motorized damper assembly; and  
         [0007]    [0007]FIG. 2 is a cross sectional view of a portion of the damper assembly shown in FIG. 1. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0008]    [0008]FIG. 1 is a perspective view of a motorized damper assembly  10  suitable for use in low temperature conditions, i.e., temperatures at or below freezing, such as those encountered in various refrigerators and refrigeration appliances. It is understood, however, that other applications of motorized dampers introduce similar concerns as those redressed by the present invention. Therefore, as the benefits of the invention accrue generally to motorized dampers used in a variety of applications wherein low temperature conditions present conditions conducive to frozen, jammed or impaired motor mechanisms, the present invention is not intended to be limited to any particular low temperature application, such as in a refrigerator.  
         [0009]    Damper door assembly  10  includes a door frame  12 , a damper door  14  including a sealed mounting assembly  16 , and a known motor  18  for adjusting a position of damper door  14 . Door frame  12  includes a first side  20 , a second side  22 , a bottom  24  and a top  26 . Frame first side  20  includes a damper opening  28  therethrough, and damper door  14  is rotatably mounted to frame bottom  24  and to frame top  26  and is dimensioned at least equally to the dimensions of damper opening  28  to regulate airflow therethrough. Damper door  14  is selectively positionable between a fully open position wherein airflow through damper opening  28  is substantially unimpeded by damper door  14 , as shown in FIG. 1, a fully closed position (not shown) wherein damper door  14  substantially prevents airflow through damper opening  28 , as well as to any desired position between the fully open and fully closed position.  
         [0010]    Damper door  14  is substantially vertically mounted in damper door assembly  10 , i.e., damper door  14  rotates about a substantially vertical axis. Thus, any moisture accumulating on damper door  14  is drawn by gravity to a lower end of damper door  14 , and sealed mounting assembly  16  is located in the lower end of damper door  14  and frame bottom portion  24  to prevent moisture from entering motor  18 . Thus, potential freezing of moisture on motor mechanism components (not shown) therein is avoided. For example, in one embodiment, damper door  14  is rotated by an eccentric pivot pin (not shown in FIG. 1) engaged with damper door  14  and coupled to a cam (not shown) that is, in turn, driven by gears (not shown) coupled to the motor output shaft (not shown). Thus, as the motor shaft rotates, damper door  14  is rotated open and closed. It is contemplated, however, that the sealed assembly of the present invention may be used with alternative door rotating arrangements known in the art, and furthermore may be used to seal other openings (not shown) in frame bottom portion  24  that present potential moisture leaks into motor  18  which may impair performance of damper assembly  10  in low temperature conditions.  
         [0011]    [0011]FIG. 2 is an exaggerated cross-sectional view of sealed mounting assembly  16 . Damper door  14  includes a mounting portion  30  including a body  32  defining a hollow chamber  34  therein. Door mounting portion  30  extends above frame bottom portion  24 , and a seal member  36  extends below frame bottom portion  24  and includes a horizontal portion  38  and a vertical moisture barrier  40  extending from horizontal portion  38  inside mounting portion chamber  34 . A door pivot pin  42  is received within moisture barrier  40 . In one embodiment, door pivot pin  42  is eccentrically shaped on at least at one end  44  and coupled to a motor mechanism, such as a motor driven cam (not shown). When the cam is rotated by the motor shaft, eccentric end  44  contacts door mounting portion  30  to rotate damper door  14  and change its position. In another embodiment, door pivot pin  42  is stationary and door mounting portion  30  rotates about pivot pin  42  as it rotated by a cam driven arrangement (not shown) engaging damper door  14  elsewhere than on door mounting portion  30 .  
         [0012]    Seal member moisture barrier  40  extends upwardly into mounting portion chamber  34  within door mounting portion body  32 . Mounting portion chamber  34  is therefore effectively separated into an outer chamber  46  extending between moisture barrier  40  and door mounting portion body  32 , and an inner chamber  48  extending between seal member moisture barrier  40  and door pivot pin  42 . Outer chamber  46  forms a reservoir to prevent moisture from entering inner chamber  48  and reaching components of motor  18  (shown in FIG. 1) unless the moisture travels upwardly, against gravitational forces, a sufficient height to surpass moisture barrier  40 . With strategic selection of moisture barrier  40  height, moisture entry into motor  18  can be practically eliminated.  
         [0013]    In an exemplary embodiment, seal member  36  extends from damper frame bottom portion  24 , and is attached to frame bottom portion  24  in a known manner to adequately seal the connection between seal member  36  and frame bottom portion  24 . In an alternative embodiment seal member  36  is integral to frame bottom portion  24 . Seal member  36  is fabricated from known materials and techniques so that seal member  36  is capable of withstanding expected temperature conditions in use, and in different embodiments is fabricated from the same or different materials as other components of motorized door assembly  10 .  
         [0014]    Further, moisture barrier  40  and door mounting portion body  32 , in an exemplary embodiment, extend substantially parallel to one another. In a further embodiment moisture barrier  40  and door mounting portion  32  extend substantially vertically. It is contemplated, however, that an adequate reservoir can be created in outer chamber  46  if one or both of moisture barrier  40  and door mounting portion body  32  are inclined, whether parallel or in a nonparallel fashion.  
         [0015]    In addition, in an exemplary embodiment, door mounting portion body  32  is substantially cylindrical, thereby forming a cylindrical mounting portion chamber  34  therein, and moisture barrier  40  is complementary in shape to mounting portion chamber  34 . In alternative embodiments, however, other shapes of door mounting body  32 , mounting body chamber  34 , and moisture barrier  40  may be employed to achieve the benefits of the instant invention, including non-complementary shapes of door mounting body  32 , mounting body chamber  34 , and moisture barrier  40 .  
         [0016]    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.