Patent Publication Number: US-6336339-B1

Title: Damper for refrigerators

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates, in general, to a damper for refrigerators and, more particularly, to a structural improvement in such a damper to effectively vaporize moisture drops, condensed on a higher temperature surface of a damper&#39;s baffle due to a dewing phenomenon caused by a difference in temperature between opposite surfaces of the baffle, thus allowing the baffle to be almost free from freezing on the surface. 
     2. Description of the Prior Art 
     As well known to those skilled in the art, refrigerators are machines which are designed to supply cool air, formed through heat exchanging processes of evaporators, into freezing and fresh compartments, thus keeping food within the two compartments while freezing the food within the freezing compartment and maintaining the freshness of food within the fresh compartment for an expected period of time. In conventional refrigerators, the supply of cool air for the freezing and fresh compartments is automatically controlled in order to accomplish preset desired temperatures within the compartments. In order to accomplish such a cool air supply control during an operation of a refrigerator, a damper is installed within the refrigerator. That is, the supply of cool air for the freezing and fresh compartments in conventional refrigerators is automatically and repeatedly stopped and restarted under the control of a damper. 
     In conventional refrigerators, the damper is installed on the cool air passage for the fresh compartment. FIGS. 1 and 2 show the construction of a conventional damper used for controlling the supply of cool air for the fresh compartment in a refrigerator. 
     As shown in FIGS. 1 and 2, the damper  10  is installed on the cool air passage for the fresh compartment of the refrigerator and controls the cool air supply for the fresh compartment. The arrow in FIG. 2 designates the flow direction of cool air from an evaporator into the fresh compartment through the damper  10 . That is, the cool air, formed through a heat exchanging process performed by the evaporator installed within a heat exchanger chamber defined at the rear of the fresh compartment, is supplied into the fresh compartment under the control of the damper  10 . 
     The damper  10  of FIGS. 1 and 2 is disclosed in U.S. Pat. No. 5,876,014. In a detailed description, the above damper  10  comprises a frame  12  having a cool air passing hole  12   a , with a baffle  14  being hinged to the frame  12  and controlling the cool air passing hole  12   a . The above baffle  14  is rotatable relative to the frame  12  by the rotating force of a stepping motor  20  in opposite directions, thus selectively opening or closing the cool air passing hole  12   a.    
     In order to transmit the rotating force of the stepping motor  20  to the baffle  14 , a gear transmission mechanism is provided in the damper  10  as follows. That is, a pinion gear  22  is fixed to the rotating shaft  20   a  of the stepping motor  20  and transmits the rotating force of the motor  20  to a sectoral gear  24 . The above sectoral gear  24  is fixed to the rotating shaft P of the baffle  14 , and so the rotating shaft P is rotatable in cooperation with a rotating action of the sectoral gear  24 . The stepping motor  20  and the gear transmission mechanism constitutes a drive unit for the baffle  14 . When the rotating shaft P is rotated by the rotating action of the sectoral gear  24 , the baffle  14  is rotated from its closed position shown by the solid line in FIG. 2 to its open position shown by the phantom line in the drawing, thus opening the cool air passing hole  12   a.    
     However, such a conventional damper  10  is problematic as follows. That is, when the baffle  14  is kept in its closed position as shown by the solid line in FIG. 2, there is an undesirable difference in temperature between opposite surfaces of the baffle  14 . The left-hand surface of the baffle  14  in the drawing directly faces the cool air discharged from the evaporator, and so said surface is lower in temperature than the right-hand surface of the baffle  14  facing the fresh compartment. That is, the right-hand surface of the baffle  14  is higher in temperature than the left-hand surface due to the temperature within the fresh compartment and is dampened due to moisture escaping from food kept in the fresh compartment. 
     Due to such a difference in temperature between opposite surfaces of the baffle  14 , moisture is condensed and forms small drops on the right-hand surface of the baffle  14  facing the fresh compartment. Such small drops of moisture condensed on the surface of the baffle  14  are undesirably frozen particularly at the edge of the baffle  14  due to the cool air flowing on the baffle  14 . The rotating shaft P of the baffle  14  in the conventional damper  10  may be thus easily frozen, and may fail to smoothly rotate the baffle  14 . 
     Such a problem, experienced in the conventional damper, ill-affects the operational function of the damper and finally deteriorates the operational reliability of refrigerators. This reduces the market competitiveness of the refrigerators. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a damper for refrigerators, which is designed to allow the baffle, installed around a cool air passage for the fresh compartment of a refrigerator, to be free from freezing. 
     Another object of the present invention is to provide a damper for refrigerators, which gives an appropriate quantity of moisture to the cool air for the fresh compartment of a refrigerator, thus allowing food in the fresh compartment to maintain its moisture and freshness for a desired period of time. 
     In order to accomplish the above object, the primary embodiment of the present invention provides a damper for refrigerators, comprising: a frame installed in the cool air passage within a refrigerator and having a cool air passing hole; a baffle selectively opening or closing the air passing hole of the frame; a rotating shaft rotatably holding the baffle relative to the frame while being installed on the baffle at a position between upper and lower edges of the baffle; and a drive unit rotating the baffle relative to the frame. 
     In the above damper, the baffle is rotatable around the rotating shaft so as to selectively open or close the cool air passing hole of the frame while exposing moisture drops condensed on a surface thereof to cool air flowing through the cool air passage when the baffle is rotated to open the cooling air passing hole. 
     In addition, the drive unit comprises: a drive power source generating a rotating force for the baffle; and a gear transmission mechanism transmitting the rotating force of the drive power source to the baffle. 
     The second embodiment of this invention provides a damper for refrigerators, comprising: a frame installed in a cool air passage within a refrigerator and having a cool air passing hole; a baffle selectively opening or closing the air passing hole of the frame; a link extending from an edge of the baffle while forming an angle between the link and the baffle, thus holding the baffle, the link having a hinge pin at an outside end thereof; and a drive unit rotating the baffle relative to the frame. 
     In the above damper, the baffle is rotatable around the hinge pin so as to selectively open or close the cool air passing hole of the frame while exposing moisture drops condensed on a surface thereof to cool air flowing through the cool air passage when the baffle is rotated to open the cooling air passing hole. 
     On the other hand, the angle between the baffle and the link ranges from 90° to 135°. 
     In the above damper, the drive unit comprises: a drive power source generating a rotating force for the baffle; and a gear transmission mechanism transmitting the rotating force of the drive power source to the baffle. 
     In the damper of this invention, the moisture drops, condensed on the higher temperature surface of the baffle due to a temperature difference between opposite surfaces of the baffle while the baffle is closed, are fully exposed to the dry cool air when the baffle is opened. It is thus possible for the moisture drops to be quickly evaporated and absorbed by the dry cool air. The damper thus effectively prevents the baffle from freezing due to the condensed moisture drops and allows the baffle to be smoothly operated without failure. This finally improves the operational reliability of the damper and refrigerators. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a front view of a conventional damper for refrigerators; 
     FIG. 2 is a sectional view showing the operation of the conventional damper of FIG. 1; 
     FIG. 3 is a sectional view, showing a baffle included in the damper for refrigerators in accordance with the primary embodiment of this invention when the baffle closes the cool air passage for the fresh compartment of a refrigerator; 
     FIG. 4 is a sectional view, showing the baffle FIG. 3 when the baffle opens the cool air passage for the fresh compartment; 
     FIG. 5 is a sectional view of a damper for refrigerators in accordance with the second embodiment of the present invention; and 
     FIG. 6 is a sectional view, showing a post-rotating position of a baffle included in the damper according to the second embodiment of this invention when the angle between the baffle and links of the damper is undesirably set to be larger than 135°. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 3 shows a damper for refrigerators in accordance with the primary embodiment of this invention. As shown in the drawing, the damper according to the primary embodiment of this invention comprises a frame  32  having a cool air passing hole  32   a , with a baffle  34  being hinged to the frame  32  and controlling the cool air passing hole  32   a.    
     In the same manner as that described for the conventional damper, the frame  32  is installed on the cool air passage for the fresh compartment and allows cool air to be supplied from an evaporator into the fresh compartment through the cool air passing hole  32   a  of the frame  32 . Since the baffle  34  controls the cool air passing hole  32   a  of the frame  32 , the baffle  34  controls the supply of cool air for the fresh compartment. 
     The above baffle  34  is hinged to the frame  32  by a rotating shaft P provided at the central portion of the baffle  34 . That is, the baffle  34  is rotatable along with the rotating shaft P relative to the frame  32  in opposite directions, thus selectively opening or closing the cool air passing hole  32   a . In the present invention, the above rotating shaft P may be cast with the baffle  34  into a single structure. Alternatively, the rotating shaft P may be produced separately from the baffle  34  prior to being fixed to the baffle  34 . 
     The rotating shaft P is rotatable by the rotating force of stepping motor  40 . In order to transmit the rotating force of the stepping motor  40  to the rotating shaft P, a gear transmission mechanism is provided in the damper of this invention as follows. That is, a sectoral gear  44  is fixed to the rotating shaft P of the baffle  34 , thus being rotatable along with the baffle  34 . The above sectoral gear  44  is provided with teeth on its arcuate edge and engages with the teeth of a pinion gear  42 . The above pinion gear  42  is fixed to the rotating shaft  40   a  of the stepping motor  40  installed at a side of the damper. The stepping motor  40  and the gear transmission mechanism constitutes a drive unit for the baffle  34 . 
     The rotating force of the stepping motor  40  is transmitted to the rotating shaft P and rotates the shaft P along with the baffle  34  as follows. When the stepping motor  40  is turned on, the rotating shaft  40   a  of the motor  40  is rotated along with the pinion gear  42 . The rotating force of the pinion gear  42  is transmitted to the sectoral gear  44 , thus rotating the sectoral gear  44 . Therefore, the rotating shaft P along with the baffle  34  is rotated in response to such a rotating action of the sectoral gear  44 . The toothed circumference of the arcuate edge of the sectoral gear  44  determines the rotating angle of the baffle  34 , and so it is necessary to set the toothed circumference of the sectoral gear  44  in accordance with a desired rotating angle of the baffle  34 . 
     The operational effect of the damper according to the primary embodiment of this invention will be described hereinbelow in conjunction with FIGS. 3 and 4. 
     When the baffle  34  is in its closed position as shown in FIG. 3, there is a temperature difference between opposite surfaces of the baffle  34 . That is, the left-hand surface of the baffle  34 , directly facing the cool air discharged from the evaporator, is lower in temperature than the right-hand surface of the baffle  34  facing the fresh compartment. Due to such a difference in temperature between opposite surfaces of the baffle  34 , moisture is condensed and forms small drops on the right-hand surface of the baffle  34 . Even though an insulation material  35  is provided at the junction between the baffle  34  and the cool air passing hole  32   a  of the frame  32 , it is almost impossible for the insulation material  35  to prevent a formation of such small drops on the right-hand surface of the baffle  34  by a condensation of moisture on said surface due to a temperature difference between the two surfaces. 
     The baffle  34  is opened when it is desired to supply cool air into the fresh compartment. In order to open the baffle  34 , the pinion gear  42  is rotated clockwise around the rotating shaft P in FIG. 3 by the rotating force of the stepping motor  40 , thus allowing the sectoral gear  44  to be rotated counterclockwise. The rotating shaft P along with the baffle  34  is rotated counterclockwise, thus opening the cool air passing hole  32   a  of the frame  32  as shown in FIG.  4 . 
     When the baffle  34  opens the cool air passing hole  32   a  as described above, cool air is supplied from the evaporator into the fresh compartment through the open hole  32   a . In such a case, the cool air for the fresh compartment flows through two passages A and B divided by the open baffle  34 . That is, the baffle  34  in its open position is horizontally positioned within the cool air passage for the fresh compartment in a way such that the surface of the baffle  34 , coated with the condensed moisture drops, is fully exposed to cool air flowing through the passage A. 
     The cool air, flowing through the passage A, is dry air having a low temperature, and so the moisture drops on the surface of the baffle  34  are quickly evaporated by the cool air prior to being absorbed by the cool air. 
     The construction of the damper of this invention may be altered as follows. 
     FIG. 5 shows a damper for refrigerators in accordance with the second embodiment of this invention. As shown in the drawing, the damper according to the second embodiment is designed to allow the baffle  54  to be rotatable around a hinged shaft, spaced from the baffle body by a distance, so as to control the cool air passing hole  53   a  of the frame  52 . In this embodiment, when the baffle  54  is opened, the surface of the baffle  54 , coated with moisture drops condensed on the surface due to a temperature difference between opposite surfaces of the baffle  54 , is thus fully exposed to cool air discharged from the evaporator into the fresh compartment. 
     In order to accomplish the above structure of the damper according to the second embodiment, two links  56  are fixed to opposite upper corners of the baffle  54  at positions around the top edge of the right-hand surface  54   a  of the baffle  54 , with an angle α being formed between the right-hand surface  54   a  and each of the links  56 . A rotating pin  56   a  is provided at the outside ends of the two links  56  and acts as a rotating axis of the baffle  54 . A sectoral gear  64  is fixed to the rotating pin  56   a  and engages with a pinion gear  62  integrated with the rotating shaft  60   a  of a stepping motor  60 . The rotating pin  56   a  along with the baffle  54  is thus rotatable in opposite directions by the rotating force of the stepping motor  60  transmitted to the shaft  56   a  through the pinion  62  and the sectoral gear  64 , thus selectively opening or closing the cool air passing hole  52   a  of the frame  52 . The damper according to the second embodiment is characterized in that the rotating axis of the baffle  54  is not positioned on the baffle body, but is positioned at a position spaced apart from the baffle body by a predetermined distance different from the primary embodiment of this invention. 
     When the stepping motor  60  is started, the baffle  54  is rotated around the rotating pin  56   a  counterclockwise, thus reaching its open position as shown by the phantom line of FIG.  5  and opening the cool air passing hole  52   a  of the frame  52 . In such a case, the junction points between the baffle  54  and the links  56  are moved downward when the baffle  54  is rotated counterclockwise from its closed position to its open position, thus allowing the surface  54   a  of the baffle  54  coated with the condensed moisture drops to be fully exposed to the cool air flowing in the linear cool air passage formed by the open hole  52   a  of the frame  52 . It is thus possible to evaporate the moisture drops on the surface  54   a  using the dry cool air. 
     The links  56 , included in the damper of the second embodiment, are very important elements and will be described in more detail hereinbelow. 
     In the damper according to the second embodiment, it is necessary to appropriately set the angle α between the baffle body and the links  56 . That is, when the angle a is set to be less than 90°, the baffle  54  is undesirably interfered with the frame  52  during a rotating action of the baffle  54 . On the other hand, when the angle α is set to be larger than 135°, the baffle  54  in its fully open position is undesirably positioned outside the linear cool air passage as shown in FIG. 6, and fails to accomplish the object of this invention. That is, when the angle a is set to be larger than 135°, the post-rotating position of the junction points between the baffle body and the links  56  is undesirably moved upward from the pre-rotating position of said junction points, thereby undesirably allowing the baffle  54  to be positioned outside the linear cool air passage for the fresh compartment. Therefore, it is necessary to set the angle α between the baffle  54  and the links  56  in the second embodiment of this invention to a range of 90°˜135°. 
     The length of each link  56  is determined as follows. The length of each link  56  determines the amount of cool air flowing over the surface  54   a  of the baffle  54 . When each of the links  56  is lengthened, it is possible to position the baffle  54  at a lower position close to the central axis of the cool air passage when the baffle  54  is fully opened. In such a case, the moisture drops condensed on the surface  54   a  of the baffle are more quickly evaporated. However, it should be understood that it is necessary to appropriately determine the length of each link  56  while considering the fact that such an increase in length of each link  56  also results in both an increase in moment around the rotating pin  56   a  and a limitation while designing and installing the damper. 
     The operational effect of the damper according to the second embodiment of this invention will be described hereinbelow in conjunction with FIG.  5 . In the same manner as that described for the damper according to the primary embodiment, the baffle  54  of the second embodiment in its closed position is inevitably coated with moisture drops condensed on its surface  54   a  due to a temperature difference between its opposite surfaces. 
     The baffle  54  is opened when it is desired to supply cool air into the fresh compartment. In order to open the baffle  54 , the pinion gear  62  is rotated by the rotating force of the stepping motor  60 , thus allowing the sectoral gear  64  to be rotated. The links  56  along with the baffle  54  are thus rotated to open the cool air passing hole  52   a  of the frame  52 . Therefore, the baffle  54  is horizontally positioned within the linear cool air passage for the fresh compartment as shown by the phantom line in FIG.  5 . The cool air from the cool air passing hole  52   a  of the frame  52  flows through two passages A′ and B′ divided by the horizontally positioned baffle  54 . The moisture drops formed on the surface  54   a  of the baffle  54  are exposed to the dry cool air flowing through the passage A′, thus being quickly evaporated and absorbed by the cool air. 
     As described above, the damper of this invention is designed to expose the moisture drops, condensed on one surface of a baffle  34  or  54 , to dry cool air discharged from the evaporator into the fresh compartment when the baffle is opened. In order to accomplish the above operational effect of the damper, the baffle  34  or  54  is rotatably held by a rotating shaft or a hinge pin positioned at the center of the baffle body or at a rotating axis spaced apart from the baffle body by a distance. 
     Of course, it should be understood that the construction of the baffle included in the damper of this invention may be changed from the above-mentioned construction shown in FIGS. 3 to  5  if such a change does not affect the functioning of this invention. 
     That is, the preferred embodiments use a stepping motor  40  or  60  as a source of the rotating force for the baffle  34  or  54 . However, such a rotating force may be generated by another conventional device in place of the stepping motors  40  and  60  if the device gives a desired rotating force to the baffle  34  or  54  so as to rotate the baffle around a rotating shaft and to control the cool air passage for the fresh compartment. 
     In the preferred embodiments, the rotating force of the stepping motor  40  or  60  is transmitted to the rotating shaft P or the hinge pin  56   a  through the sectoral gear  44  or  64 . However, it should be understood that such a power transmission from the stepping motor to the rotating shaft or the hinge pin in the damper of this invention may be accomplished by another gear in place of such a sectoral gear. That is, the shape of the transmission gear used for transmitting the rotating force of the stepping motor to the rotating shaft or the hinge pin is not limited to such a sectoral shape. 
     In the dampers according to the preferred embodiments of this invention, the baffle  34  or  54  is integrated with the rotating shaft P or the hinge pin  56   a  so as to be rotatable along with the rotating shaft P or the hinge pin  56   a  by the rotating force from a stepping motor. However, it should be understood that the shaft P or  56   a  may be designed to form a fixed rotating axis for the baffle  34  or  54 , with the baffle being designed to be rotatable around the fixed rotating axis by the rotating force of a stepping motor. 
     As described above, the present invention provides a damper for refrigerators. This damper is designed to effectively vaporize moisture drops, condensed on a higher temperature surface of a damper&#39;s baffle due to a difference in temperature between opposite surfaces of the baffle, thus allowing the baffle to be almost free from freezing on the surface. In order to accomplish the above object, the damper of this invention is designed to expose the baffle to dry cool air at a surface of the baffle coated with condensed moisture drops when the baffle is opened. The moisture drops are thus quickly evaporated and absorbed by the dry cool air, and so the damper is almost free from freezing of the surface of the baffle or of the drive unit for the baffle. This finally allows the damper to be reliably operated irrespective of condensation of moisture drops on the baffle and accomplishes a desired operational reliability of refrigerators. 
     A collateral advantage of the damper according to the invention resides in that the moisture drops on the baffle are evaporated and absorbed by cool air for the fresh compartment. Such cool air desirably moisturizes food kept in the fresh compartment, thus overcoming a conventional problem of drying food in the fresh compartment. The cool air, laden with an appropriate amount of moisture, finally allows desired freshness of food within the fresh compartment to be maintained for an expected period of time. 
     Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.