Patent Document

BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to environmental temperature controls and more particularly to systems for controlling temperatures in multiple compartment devices. 
     2. Background Information 
     The goal of most multiple compartment designs is to quickly and efficiently control the discrete compartment temperatures using one cold air source. This task becomes more difficult when there is a sudden temperature change in a compartment, for example, such as when a refrigerator door is opened and then closed. 
     Typically refrigerators have a partition that separates the freezer from the fresh food compartment. Refrigerators also have a cold air source, which directs cold air into the freezer. There is typically an aperture in the partition that allows the cold air in the freezer to migrate into the fresh food compartment. A damper selectively covers and uncovers the aperture in the partition to control the amount of cold airflow from the freezer to the fresh food compartment. Refrigerators usually have thermostats that control the cold air source. 
     One arrangement for controlling refrigerator compartment temperatures is to use a manually controlled damper and a thermostat located in the fresh food compartment. If the temperature in the freezer compartment suddenly increases, the damper will not move, and the cold air source will turn on when the warmer air has migrated from the freezer to the thermostat in the fresh food compartment. A drawback associated with this arrangement is that in most refrigerators, the freezer is located above the fresh food compartment and since heat rises, it could take a significant amount of time before the warmer air migrates down from the freezer to the thermostat in the fresh food compartment. This is especially true if the manual damper was positioned to substantially cover the aperture. 
     One proposed solution to this problem is to incorporate an automatic damper controller and a thermostat located in the freezer compartment rather than in the fresh food compartment. More specifically, the thermostat would control the cold air source in response to the temperature of the freezer compartment. Also, the automatic damper controller would incrementally control the damper in response to the temperature of the fresh food compartment. 
     A drawback to this system is that when the freezer compartment is cooled to its set point temperature, the cold air source will shut off, even if the fresh food compartment is warm and has not been sufficiently cooled. The set point temperatures refer to the preset high and low temperature range settings of the compartments. For example, when the air temperature in the fresh food compartment reaches a set point temperature, the cold air source will be either turned on or off. Hence, a need exists for a system which will quickly and efficiently control temperatures in a multiple compartment device in response to compartment temperature changes. 
     SUMMARY OF THE INVENTION 
     According to an embodiment of the invention, an actuator is provided for controlling temperatures in a multiple compartment device. The actuator includes a housing and a linear oscillator disposed within the housing. The linear oscillator is disposed integrally with a push rod, wherein the linear oscillator reciprocably moves the push rod along its longitudinal axis. In addition, the actuator includes a holder including a rigid member and a pin aperture. A sliding member has a knob on one end and a first clip connector at an other end, the sliding member having a range of motion limited by the rigid member. The push rod has a second clip connector on one end, which is coupled to the first clip connector of the sliding member. A lever arm has a first end and a second end, the first end including a protruding member and the second end including a lever arm aperture and a lever arm pin. The knob of the sliding member is pivotably engaged with the lever arm aperture and the lever arm pin is pivotably engaged with the pin aperture. The protruding member is adapted to pivotably couple with the damper. 
     The present invention provides, in another aspect, a method of fabricating an actuator for controlling temperatures in a refrigerator. A first step of this method is to provide a linear oscillator which is operable in response to input from a temperature sensor. Additional steps include integrally disposing a push rod with the linear oscillator, wherein the linear oscillator reciprocably moves the push rod along its longitudinal axis. A holder is provided which includes a rigid member and a pin aperture. A sliding member is provided which has a knob at one end and first clip connector at an other end, the sliding member having a range of motion limited by the rigid member. A second clip connector is provided on one end of the push rod. The second clip connector is coupled to the first clip connector of the sliding member. A first end of a lever arm is provided with a protruding member which is coupled with a damper. In this regard, those skilled in the art will recognize that any number of well-known coupling configurations, such as a pivot pin/receptacle, hinge, cam/follower, or resilient connector such as a metallic, polymeric or elastomeric spring, may be used in lieu of any of the coupling arrangements disclosed herein, without departing from the spirit and scope of the present invention. 
     A second end of the lever arm is provided with a lever arm aperture and a lever arm pin. The knob is pivotably engaged with the lever arm aperture, and the lever arm pin is pivotably engaged with the pin aperture. 
     The above and other features and advantages of this invention will be more readily apparent from a reading of the following detailed description of various aspects of the invention taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-sectional schematic representation of a refrigerator, which includes a prior art refrigeration system; 
     FIG. 2 is a cross-sectional schematic view similar to that of FIG. 1, of a refrigerator including a refrigeration system which incorporates an actuator of the present invention; 
     FIG. 3 is an exploded view, on an enlarged scale, of the actuator of FIG. 2; 
     FIG. 4 is a partially broken away, front sectional view, on an enlarged scale, of a portion of a refrigerator including an embodiment of the actuator of FIGS. 2 and 3, with a damper in a closed position; and 
     FIG. 5 is a view similar to that of FIG. 4, with the damper in an open position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the Figures set forth in the accompanying Drawings, the illustrative embodiments of the present invention will be described in detail hereinbelow. 
     For clarity of exposition, like features shown in the accompanying Drawings shall be indicated with like reference numerals and similar features as shown in alternate embodiments in the Drawings shall be indicated with similar reference numerals. 
     As shown in FIG. 1, a typical prior art refrigerator  10  includes a relatively low temperature freezer compartment or freezer  12  and a relatively high temperature fresh food compartment  14 . The freezer  12  and fresh food compartment  14  are usually separated by a partition  16  having an opening or aperture  18 , which extends from the freezer  12  to the fresh food compartment  14 . A cold air source  20 , which normally includes a refrigerant condenser, evaporator (not shown) and a fan, is used to provide cold air to the freezer  12 . The cold air source  20  is generally located behind the refrigerator  10  or below the fresh food compartment  14 . In any event, it should be understood that most refrigerators include an air circulating system including a cold air source  20 , which provides cold air directly to the freezer  12 , while a portion of the cold air  28  is directed to the fresh food compartment  14  through an aperture  18  in the partition  16 . In operation, the prior art cold air source  20  is controlled by a signal from the thermostat  26  located in the freezer  12 . Also, the damper  22  and prior art automatic damper controller  24  are indirectly controlled by the temperature in the fresh food compartment  14 . 
     As shown in FIG. 2 an embodiment of a refrigerator system  100 , which incorporates the adapter  102  of the present invention, comprises a relatively low temperature freezer compartment or freezer  120  and a relatively high temperature fresh food compartment  140 . 
     The freezer  120  and fresh food compartment  140  are separated by a partition  160  having an opening or aperture  180 , which extends from the freezer  120  to the fresh food compartment  140 . The air circulating system includes a cold air source  200 , which provides cold air directly to the freezer  120 , while a portion of the cold air is directed to the fresh food compartment  140  through an aperture  180  in the partition  160 . The cold air source  200  is located behind the refrigerator  100  or below the fresh food compartment  140 . 
     Also shown in FIG. 2, is the actuator  102  which controls the damper  220  in response to the temperature of the freezer  120 , as opposed to common damper controllers which actuate in response to the temperature of the fresh food compartment (see FIG.  1 ). Moreover, this embodiment of a refrigeration system includes a thermostat  104  located in the fresh food compartment  140 , in contrast to conventional systems, which typically have the thermostat in the freezer (see FIG.  1 ). 
     In operation, as shown in FIG. 2, the cold air source  200  is controlled in response to a signal from the thermostat  104  which senses the temperature of the fresh food compartment  140 . The thermostat may be located in any part of the fresh food compartment, but is typically located substantially away from the partition aperture (i.e., at an opposite end of the compartment  140  therefrom). The thermostat may be attached to the refrigerator wall or contained in the walls. The damper  220  and automatic damper controller or actuator  102  are actuated by a signal from the sensing end  108 , of the temperature sensor  106 , which senses the temperature in the freezer  120 . 
     Also shown in FIG. 2 are the lever arm  138 , the bellows  122  and the frame  110 . In a preferred embodiment, the frame  110  is located on the partition  160  within the fresh food compartment  140 . The frame  110  may be formed from a single injection molded piece or from any other suitable material, such as any metal or plastic. 
     Turning now to FIG. 3, various components of the actuator  102  are shown, with the exception of the linear oscillator or bellows  122  (see FIG.  4 ). As shown, the temperature sensor  106 , having a sensing end  108 , is attached to the frame  110  of actuator  102 . As shown, the temperature sensor extends from the frame up through the partition  160  and then terminates in the freezer  120  at the sensing end  108  (as shown in FIG.  2 ). As also shown, the sensing end  108  may be a bulb shape and be filled with fluid, such as, for example, in the event the temperature sensor is a capillary tube bulb. 
     One skilled in the art will recognize that a capillary tube bulb is a hollow tubular device that has a fluid filled bulb on one of its ends, and is typically used for sensing temperature changes. Another component of the actuator is the frame  110 , which is shown in FIG.  3 . In one embodiment, the frame comprises a housing  112  and an elongated holder  114  fabricated as two distinct parts. The housing may be rectangular shaped and have bolts  118  and boltholes  117  to allow for easy mounting to the partition or refrigerator. The elongated holder  114  includes a rigid member  134 , a rigid member pin aperture  136  and a guide hole  116 . 
     A push rod  124  extends out of the housing  112  and in through the guide hole  116  and connects to a sliding member  128 . The push rod may also have one or more second clip connectors or annular grooves  126  which may be used to attach the push rod to the first clip connector  132  of the sliding member  128 . In another embodiment, the push rod  124  and sliding member  128  are fabricated as one piece (not shown). A sliding member  128  which may be a rectangular shaped member having semicircular grooves or a first clip connector  132  on an end, for clipingly attaching to the second clip connector  126 , is shown in FIG.  3 . The sliding member  128  extends substantially perpendicularly to the push rod  124 . 
     The sliding member may also have a sliding member knob or cylindrical portion  130 , which may be cylindrical in shape. This sliding member knob  130  is disposed inside an aperture  146  in the lever arm  138 . The rigid member  134  limits the movement of the sliding member  128  and indirectly limits the stroke of the damper  220 . In one embodiment (not shown) the elongated holder  114  and the housing  112  may be formed as a single, integrated device. The rigid member  134  may be non-rectangular in shape. The elongated holder  114  also includes a holder pivot hole or pin aperture  136  for accepting a pindle or lever arm pin  142 . The housing  112  may be attached to the elongated holder  114  with bolts  118  or other suitable fastening devices. 
     In a preferred embodiment the lever arm  138  has a first end  145  and second end  143 . The first end  145  has a protruding member  147  for engaging with the damper  220  and a second end  143  has a lever arm aperture  146  and a lever arm pin  142 . The lever arm aperture  146  and a lever arm pin  142  respectively engage with the cylindrical portion or sliding member knob  130  and the holder pivot hole or rigid member pin aperture  136 . The lever arm pin  142  may have a spring type retaining step  144  to substantially keep the lever arm  138  attached to the elongated holder  114 . The protruding member  147  is disposed in an orifice formed in the damper  220  (FIGS.  4  &amp;  5 ). 
     The orifice in the damper  220  is larger than the protruding member  147  in a direction perpendicular to the partition  160  to allow movement in that direction, so that the lever arm  138  may be rigid and yet still move the damper  220  in a direction parallel to the partition  160 . Such movement will be discussed in greater detail hereinbelow with respect to FIGS. 4 &amp; 5. The lever arm pin  142  is rotatably contained in the rigid member pin aperture  136 , which allows the first end  145  of the lever arm  138  to pivot about pin  142 . The lever arm aperture  146  slidably receives the sliding member knob  130  therein. The sliding member knob  130  rotatably drives the lever arm  138  to generate the aforementioned pivotal movement as the linear oscillator (i.e., bellows)  122  expands or contracts. In another embodiment (not shown), the damper  220  and the lever arm  138  may be fabricated as one piece. 
     As best shown in FIG. 4, the actuator  102  may move the damper  220  to a closed position in which the aperture  180  is covered by the damper  220 . Conversely, as best shown in FIG. 5, the actuator  102  may also move the damper  220  to an open position in which the aperture  180  is not covered by the damper  220 . When the damper  220  is in the open position, the colder air in the freezer  120  begins to sink into the fresh food compartment  140 . 
     As also shown in FIG. 4, the actuator  102  preferably comprises a bellows  122  and a frame  110 . The frame  110  may also include one or more control knobs  123  for modifying the stroke of the bellows, and in turn, the stroke of the damper  220 . The bellows  122  is located in the frame  110 , which, as discussed hereinabove, may be located inside the fresh food compartment  140 . The bellows  122  is filled with refrigerant or other similar fluid capable of appreciably expanding and contracting in response to variations in temperature. When the temperature changes, the bellows fluid expands or contracts to cause the bellows  122  to axially expand or contract. This contraction or expansion moves the push rod  124 , which is connected to one end of the bellows. 
     As shown and described herein, the linear oscillator preferably includes a fluid filled bellows. However, the skilled artisan should recognize that any device capable of generating a linear, oscillating or reciprocating movement, such as an electrically or electronically controlled linear actuator, may be used without departing from the spirit and scope of the present invention. 
     An important aspect of the refrigeration system  100  is that the cold air source  200  is actuated in response to the temperature of the air in the fresh food compartment  140  and not the temperature of the air in the freezer  120 . The thermostat  104 , which controls the cold air source  200 , is located in the fresh food compartment  140  and the actuator  102  controls the damper  220  in response to the air temperature in the freezer  120 . This refrigeration system  100  relatively accurately and quickly controls the temperature in the fresh food compartment. 
     Table 1 compares the cooling process steps of this refrigeration system  100  to a previous system. The cooling process steps are the different steps that each system takes in response to a temperature variation in the fresh food compartment. For convenience, “ffc” will be used to designate “fresh food compartment”. The set point temperatures refer to the preset high and low temperature range settings of the compartments. For example, when the air temperature in the fresh food compartment reaches a set point temperature, the cold air source will be either turned on or off. 
     
       
         
               
             
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Comparison of Cooling Process Steps 
               
             
          
           
               
                 Steps 
                 Previous System 
                 Refrigerator System (100) 
               
               
                   
               
               
                 1 
                 The cold air source has just 
                 The cold air source has just 
               
               
                   
                 turned off because the 
                 turned off because the ffc 
               
               
                   
                 freezer has reached its set 
                 has reached its set point 
               
               
                   
                 point temperature. The 
                 temperature. The damper is 
               
               
                   
                 damper is partially or fully 
                 fully open. 
               
               
                   
                 closed. 
               
               
                 2 
                 The ffc temperature increases 
                 The ffc temperature increases 
               
               
                   
                 because the ffc door is 
                 because ffc door is opened 
               
               
                   
                 opened. 
               
               
                 3 
                 Gradually the automatic 
                 The  cold air source is turned   
               
               
                   
                 damper begins to open in 
                   on  because the thermostat in 
               
               
                   
                 response to the temperature 
                 the ffc senses a temperature 
               
               
                   
                 increase 
                 change. 
               
               
                 4 
                 The warmer air begins to mix 
                 The warmer air starts rising 
               
               
                   
                 with the colder freezer air 
                 into the freezer and the cold 
               
               
                   
                 and eventually the damper 
                 air starts moving into the 
               
               
                   
                 fully opens. 
                 freezer 
               
               
                 5 
                 The  cold air source is turned   
                 The cold air falls through 
               
               
                   
                   on  when the freezer air warms 
                 the aperture into the ffc and 
               
               
                   
                 up because it blends with the 
                 will not stop moving into the 
               
               
                   
                 warmer ffc air. 
                 ffc until the ffc temperature 
               
               
                   
                 (without the help of a fan) 
                 is cooled to its set point 
               
               
                   
                 temperature. 
               
               
                 6 
                 Cold air enters the freezer 
                 The damper fully opens and 
               
               
                   
                 and also starts cooling the 
                 the cold air source is off 
               
               
                   
                 ffc through the aperture by 
                 because the ffc has reached 
               
               
                   
                 mixing with the ffc air. 
                 its set point temperature. 
               
               
                 7 
                 The cold air source is turned 
                 The damper closes as the 
               
               
                   
                 off when the freezer reaches 
                 freezer warms. This prevents 
               
               
                   
                 its set point temperature, 
                 colder air from leaving 
               
               
                   
                 even though the ffc air still 
                 freezer. As the ffc warms 
               
               
                   
                 may be warm. The damper is 
                 the cold air source turns on. 
               
               
                   
                 partially or fully closed. 
               
               
                   
               
             
          
         
       
     
     One advantage of the refrigeration system  100  is that the fresh food compartment temperatures are relatively accurately maintained within the high and low set point temperature ranges. As described in Table 1, the cold air source will not turn off until the temperature of the fresh food compartment has reached its low set point temperature. Conversely, the cold air source of the previous system is turned off when the freezer reaches its low set point temperature, even though the temperature of the fresh food compartment may be much warmer than the desired set point temperature. Such control of the fresh food compartment temperature and resulting warm air in the fresh food compartment of the previous system may cause food in the fresh food compartment to spoil. 
     Another advantage of the refrigeration system  100  is that the fresh food compartment is cooled very quickly after a temperature variation, such as, for example, when the fresh food compartment door is opened up and warm outside air fills the fresh food compartment. As described in Table 1, as soon as there is a temperature variation in the fresh food compartment of the refrigeration system  100 , the cold air source is turned on (i.e., refrigeration system step  3  of Table 1) and the cold air will quickly enter the fresh food compartment. 
     Contrariwise, the previous system must first complete many process steps before the cold air source is turned on, (i.e., prior art steps  3 - 5  of Table 1) in response to a temperature variation in the fresh food compartment. 
     The actuator of the present invention may be advantageously used to easily retrofit a prior art refrigerator having a manually controlled damper. This is an inexpensive means of providing the benefits of an automatically controlled damper actuator without having to purchase or redesign a new refrigerator. In addition, the lever arm amplifies the amount of damper travel. The clip connection between the push rod and the lever arm eliminates the need for a spring. Lastly, the rigid member also limits the stroke of the lever arm to ensure accurate opening and closing of the damper. 
     The foregoing description is intended primarily for purposes of illustration. Although the invention has been shown and described with respect to an exemplary embodiment thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions, and additions in the form and detail thereof may be made therein without departing from the spirit and scope of the invention.

Technology Category: 2