Abstract:
The present invention relates to a condenser or other component that is attached to the base plate by means of integral torque tabs that are twisted underneath the base plate to draw the condenser or other component downwardly against the upper surface of the base plate. In a preferred embodiment, the torque tabs are located on the lower ends of the condenser or other component end plates. The tabs are preferably designed to be machine twisted to provide enough holding force to maintain the condenser or other component and base plate in a rigid condition.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit under Title 35, U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 61/178,089, entitled CONDENSING UNIT CONDENSER ATTACHMENT FEATURE, filed on May 14, 2009, the disclosure of which is expressly incorporated by reference herein. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to condensing units, and in particular to an attachment technique for fixing the condenser or other components to the condensing unit base plate. 
         [0004]    2. Description of the Related Art 
         [0005]    Condensing units are self-contained units typically comprising a hermetic compressor, condenser and cooling fan all mounted to a base plate and having refrigerant lines adapted for connection to a remotely located expansion valve and evaporator. In the past, the condenser has been attached to the base plate by means of removable fasteners, such as bolts or threaded studs that extend through openings in the base plate and are secured by means of nuts and washers fastened from underneath the base plate. This not only increases the parts count for the condensing unit but increases assembly time due to the necessity of attaching the various fasteners. 
       SUMMARY 
       [0006]    In the present invention, the condenser or other component is attached to the base plate by means of integral torque tabs that are twisted underneath the base plate to draw the condenser or other component downwardly against the upper surface of the base plate. In a preferred embodiment, the torque tabs are located on the lower ends of the condenser or other component end plates. The tabs are preferably designed to be machine twisted to provide enough holding force to maintain the condenser or other component and base plate in a rigid condition. 
         [0007]    In one form thereof, the present disclosure provides a condensing unit, including a base plate having a plurality of components mounted on an upper surface thereof, the components including a compressor and a condenser. At least one of the components includes a plurality of tabs extending through a corresponding plurality of slots in the base plate. The tabs include distal portions that are twisted underneath the base plate, and the tab distal portions include respective camming surfaces that tightly engage an undersurface of the base plate to tightly fix the at least one component to the upper surface of said base plate. In a preferred embodiment, the condensing unit includes a base plate having a condenser mounted on an upper surface thereof, the condenser including a plurality of tabs extending through a corresponding plurality of slots in the base plate. 
         [0008]    In another form thereof, the present disclosure provides a condensing unit including a base plate having an undersurface and a condenser mounted on an upper surface thereof, the condenser including one or more attachment elements extending through one or more corresponding attachment receiving means in the base plate. The one or more attachment elements include means for engaging the base plate such that, upon deformation, the one or more attachment means tighten against the undersurface of the base plate. 
         [0009]    In yet another form thereof, the present disclosure provides a method of attaching a condenser of a condensing unit to a base plate of the condensing unit, the method including the step of positioning the condenser to abut a base plate, the condenser having a plurality of tabs, each tab having an internal distal upper edge, and the base plate having an undersurface. The method further includes the step of aligning each tab with a corresponding slot on the base plate. The method further includes the steps of inserting each tab through the corresponding slot one the base plate such that each tab extends through the corresponding slot, and then twisting each tab to thereby draw the internal distal upper edge of each tab tightly against the undersurface of the base plate such that the condenser is locked to the base plate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: 
           [0011]      FIG. 1  is a plan view of a condensing unit incorporating the attachment mechanism of the present invention; 
           [0012]      FIG. 2  is a side elevational view of the condensing unit; 
           [0013]      FIG. 3  is a perspective view of the condenser; 
           [0014]      FIG. 4  shows a side elevational perspective view of the assembled condenser and base plate wherein the tabs are in their pre-twisted state; 
           [0015]      FIG. 5  shows a distal plan view of the assembled condenser and base plate wherein the tabs are in their pre-twisted state; 
           [0016]      FIG. 6  shows a side elevational view of the assembled condenser and base plate wherein the tabs are in their pre-twisted state; 
           [0017]      FIG. 7  shows a side elevational view of one of the end plates of the condenser; 
           [0018]      FIG. 8  shows an internal side view of one of the end plates showing an internal surface with open, unbent flanges; 
           [0019]      FIG. 9  is a perspective view of the base plate; 
           [0020]      FIG. 10  is a perspective internal side view of one of the base plates; 
           [0021]      FIG. 11  is an internal side view of one of the end plates showing an internal surface with bent flanges; 
           [0022]      FIG. 12  shows views of one of the end plates of the condenser showing the tabs in detail; 
           [0023]      FIG. 13  shows a perspective view of the condenser and base plate wherein the tabs have been twisted to their locked position; and 
           [0024]      FIG. 14  is a fragmentary elevational side end view of one of the plates and the base plate, showing the tabs twisted to their locked position; 
           [0025]      FIG. 15  is a fragmentary elevational distal plan view from underneath the base plate showing a tab twisted to its locked position; 
           [0026]      FIG. 16  is an enlarged elevational view of the base plate and end plate wherein the tabs are in their pre-twisted state; and 
           [0027]      FIG. 17  is an enlarged perspective view of the end plate and base plate with the tabs in their pre-twisted state. 
       
    
    
       [0028]    Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one exemplary embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
       DETAILED DESCRIPTION 
       [0029]    With reference to  FIGS. 1 and 2 , an exemplary condensing unit  10  is shown. It comprises a metal base plate  12  having flanges  14  and an upper surface  16  to which are mounted a hermetic compressor  18 , receiver  20  and a condenser unit  22 , the latter comprising a condenser  24  and a fan assembly  26 . Fan assembly  26  comprises a plastic housing or shroud  36  which houses motor driven fan  38 . The discharge line  28  from compressor  18  is connected to inlet  29  of the condenser  24  and outlet  31  thereof is connected by means of tube  30  to receiver  20 . Inlet and outlet ports  32  and  34 , respectively, are adapted to be connected to the evaporator unit (not shown) of the refrigeration system. 
         [0030]    Referring now to  FIG. 3 , condenser  24  comprises a pair of end plates  40  and  42 , a serpentine coil  44  carrying a refrigerant connected to the inlet  29  and outlet  31  and in good thermal connection with a plurality of cooling fins  46  in a manner well known in the art. Coil  44  includes internal portions  47  and external portions  49 . 
         [0031]    Exterior surface  41  of end plate  42  is shown in  FIG. 3 .  FIG. 12  illustrates interior surface  43  of end plate  42  in detail. End plate  42  is made of a stamped and bent piece of sheet metal, for example 18 Ga. galvanized steel, having flanges  48  and a plurality of openings  50  through which serpentine coils  44  extend as shown in  FIG. 3 . As further shown in  FIG. 3 , flanges  48  of end plate  42  are bendable to extend outwardly from exterior surface  41 , and away from the plurality of cooling fins  46 , such that a portion of flanges  48  remains adjacent to exterior surface  41 . The pair of end plates  40  and  42  may further include attachment means extending from lower end  45  of each end plate  40  and  42 , respectively, that includes tabs or similar structures to attach condenser  24  to base plate  12  by receipt through attachment receiving means in base plate  12 , such as correspondingly shaped structural openings or slots  74  ( FIG. 9 ). 
         [0032]    As shown in  FIG. 12 , at lower end  45  of end plate  42  are a pair of tabs  52  and  54  that join the main body  56  of end plate  42  through connecting areas  58  and  60  formed by notches  62  that are oriented at an angle α of, for example, 10 degrees relative to side edges  64  such that internal distal upper edges  66  of notches  62  are disposed at the same angle α relative to lower edges  68 . Each internal distal upper edge  66  acts as a camming surface for each tab  52  and  54  when tabs  52  and  54  are received into slots  74  of base plate  12  and deformed or bent to lock condenser  24  to base plate  12 . Each tab  52  and  54  additionally includes a side edge  65 . Each tab  52  and  54  further includes an internal lateral edge  59  and an internal proximal edge  61  that, together with internal distal upper edge  66 , defines notch  62 . Left hand end plate  40  is identically constructed except that it is a mirror image. 
         [0033]      FIGS. 7 and 8  illustrate interior surface  43  of end plate  42  including a plurality of openings  50 , lower end  45 , the pair of tabs  52  and  54 , and flanges  48 . Flanges  48  are shown positioned in first, outwardly bent position ( FIG. 7 ) and a second, unbent open position ( FIG. 8 ).  FIGS. 10 and 11  show interior surface  43  of end plate  40  with a plurality of openings  50 , a pair of side edges  64 , main body  56 , a pair of tabs  52  and  54 , a lower end  45 , and flanges  48  positioned in first, outwardly bent position. 
         [0034]    Referring back to  FIG. 3 , serpentine coil  44  includes segments that are folded back and forth and extend through apertures  50  of end plates  40  and  42 , where the segments of serpentine coil  44  have internal portions  47  that are positioned between the pair of end plates  40  and  42 . Further, the segments of coil  44  include external portions  49  that are positioned outside external surfaces  41  of end plates  40  and  42 , respectively. 
         [0035]      FIG. 4  shows condenser  24  being placed on upper surface  16  of base plate  12  with tabs  52  and  54  extending through slots  74  ( FIG. 9 ) of base plate  12  as shown in the lower left hand view of the assembled condenser and base plate as viewed from underneath with the lower surface of the base plate being visible. Tabs  54  and  52  and slots  74  in base plate  12  are aligned so that condenser  42  can simply be dropped in place on base plate  12  and the tabs  52  and  54  will be inserted into and extend through slots  74  as shown in the lower left hand views of  FIGS. 4 and 6 , and in the distal plan view of  FIG. 5 . 
         [0036]    Tabs  52  and  54  are then twisted by means of a suitable machine and due to the orientation of notches  62  and internal distal upper edges  66  ( FIG. 16 ), such twisting action will cause distal portions of tabs  52  and  54 , defined by side edge  65  and lower edge  68  of each tab  52  and  54 , to bend about bending axis x-x ( FIG. 17 ) so that internal distal upper edges  66  of tabs  52  and  54  will be tightly drawn against the underneath surface  72  of base plate  12  and very firmly lock condenser  24  in place. 
         [0037]    As shown in  FIG. 17 , internal distal upper edge  66  includes a sloped, non-orthogonal plane relative to base plate  12  to allow for a complete geometric tolerance range of tabs  52  and  54  of end plate  42  when tabs  52  and  54  are inserted into slots  74  in base plate  12 . Contact point A is positioned between base plate  12  and a surface of internal distal upper edge  66 . Bending will occur along axis x-x that passes through contact point A and lies on plane AA. Plane AA is the plane with a minimum resistance against bending force P that is applied by the twisting machine (not shown). As shown in  FIG. 16  and, in particular,  FIG. 17 , the inclined surfaces of internal distal upper edges  66  as tabs  52  and  54  are bent rearwardly exert a type of camming action against the lower surface of base plate  12  that pulls end plates  40  and  42  against the upper surface of base plate  12  to lock condenser  24  against base plate  12 .  FIGS. 13 and 15  illustrate distal plan views of condenser  24  attached to base plate  12  showing internal distal upper edges  66  bent and twisted into a locked position, where  FIG. 15  shows a rearward bend and  FIG. 13  shows an alternative frontward (or forward) bend.  FIG. 14  shows external surface  41  of end plate  40  from an elevational side view showing tabs  52  and  54  similarly bent and twisted into a locked position. 
         [0038]    While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.