Patent Publication Number: US-6341830-B1

Title: Bottom structure for refrigerators

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates, in general, to refrigerators and, more particularly, to the bottom structure for refrigerators. 
     2. Description of the Prior Art 
     Referring to FIG. 1, the structure for conventional refrigerators is described hereafter. As shown in the drawing, the structure includes an exterior casing  2  and an interior casing  4 . The exterior casing  2  consists of a top plate and two side plates, is made of metal plates and defines the exterior of the refrigerator. The interior casing  4  is disposed in the exterior casing  2 , is made of a synthetic resin plate and defines a freezer compartment and a refrigerator compartment. 
     The gap between the exterior and interior casings  2  and  4  is filled with insulating urethane foaming liquid, thereby forming a foam layer. In order to form the foam layer, after the interior casing  4  is positioned in the exterior casing  2 , a front center panel  7  is provided at the front of the exterior casing  2 , a bottom plate  8  is provided at the bottom of the exterior casing  2  and a back plate  6  is provided at the rear of the exterior casing  2 . Thereby, the gap between the exterior and interior casings  2  and  4 , through which the insulating urethane foaming liquid is able to leak, is blocked. 
     Incidentally, a compressor base plate  10  is positioned under the rear part of the bottom plate  8  so as to define a machine compartment and support a compressor (not shown) mounted in the machine compartment. 
     In brief, according to the conventional structure of the refrigerator, the lower structure of the refrigerator consists of the bottom plate  8  and the compressor base plate  10 . 
     In the conventional structure of the refrigerator, the exterior casing  2 , the bottom plate  8  and the compressor base plate  10  are made of metal plates. When the conventional structure is made of the metal plates, the connection strength between the parts of the structure is lacking, thus being easily damaged by the external impact. In particular, when an external impact is applied to the structure as may occur in the case where the refrigerator is transported or the refrigerator is set down on the floor, the connecting portion between the external casing  2  and the bottom plate  8  may be broken or deformed, thus showing a defect in strength. Such a defect is also found in the connecting portion between the exterior casing  2  and the compression base plate  10 . 
     Further, since the lower portion of the refrigerator is made of metal, the total weight of the refrigerator is not only heavy, but the manufacturing cost of the refrigerator is high. 
     Additionally, the assembly of the refrigerator is difficult because screws are required to assemble together the metal plates, such as the external casing  2  and the bottom plate  8 . 
     Besides, after the external plate  2  is connected with the bottom plate  8 , it is needed to seal the gap between the external portion  2  and the bottom plate  8 . When the gap between the external portion  2  and the bottom plate  8  is filled with a foaming liquid so as to seal the connecting portion, the foaming liquid may leak out through the gap, thus causing a defect in the product. 
     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 lower structure of a refrigerator having improved impact resistance. 
     Another object of the present invention is to provide a lower structure of a refrigerator, allowing its parts to be simplified, thereby reducing manufacturing cost and improving assembly efficiency. 
     In order to accomplish the above object, the present invention provides a bottom structure for refrigerators, comprising the base plate made of synthetic resin utilizing an injection molding process and having a cavity filled with foam, a machine compartment casing engaging with the top surface of the base plate and defining a machine compartment of a refrigerator and fitting means for engaging the lower edge of an exterior plate with the top surface of the base plate. 
     In another embodiment, the base plate may have a plurality of fitting slits on its top surface, while the machine compartment casing may have a plurality of fitting projections at positions corresponding to the fitting slits. 
     In a further embodiment, the fitting means may comprise a fitting groove formed on the top surface of the base plate and a fitting rail formed on the lower edge of the external plate. 
     In yet another embodiment, the base plate may be partially made of metal at a machine-seating portion. 
     In a still further embodiment, the machine compartment casing may be formed of synthetic resin. 
     In an additional embodiment, the base plate may be formed with a foaming liquid inlet on its top surface, the foaming liquid inlet communicating with the cavity of the base plate and a gap between the exterior and interior casings. 
     In another embodiment, the corners or the edges of the machine compartment casing may be rounded off. 
    
    
     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 an exploded perspective view showing the structure of a conventional refrigerator; 
     FIG. 2 is an exploded perspective view showing the structure of a refrigerator according to an embodiment of the present invention; 
     FIG. 3 is a vertical, sectional view showing the structure of a refrigerator according to an embodiment of the present invention; and 
     FIG. 4 is the base plate of the structure of a refrigerator according to another embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 2 is an exploded perspective view showing a structure of a refrigerator according to an embodiment of this invention. As shown in the drawing, a base plate  20  is made of synthetic resin through an injection molding process, the base plate  20  being assembled together with the lower end of an external casing  40  and forming the bottom of the refrigerator. That is, one piece of plate manufactured by the injection molding process forms the bottom of the refrigerator. This featured structure of the embodiment differs from the lower structure of a conventional refrigerator on that the bottom of a conventional refrigerator is formed by two pieces of metal plates consisting of a bottom plate and a compressor base plate. 
     Since the base plate  20  is formed of a synthetic resin through an injection molding process, the base plate  20  is made of a single piece of plate, thereby allowing the construction of the part to be simplified with improved impact resistance. 
     As shown in FIG. 3, the base plate  20  has a cavity  28  at its middle portion, the cavity  28  being capable of being filled with foam in the process of foaming the insulating material of the refrigerator. Therefore, the base plate  20 , which has the cavity  28  filled with foam, is made by filling the cavity  28  with a foaming liquid through a foaming liquid inlet  22  formed on the top surface of the base plate  20 . 
     The process for filling the cavity  28  with a foaming liquid is desired to be integrated with the process for filling the gap between the exterior and interior casings  40  and  42 . Therefore, in the process of filling the gap between the exterior and interior casing  40  and  42 , the foaming liquid flows into the base plate  20  through the foaming liquid inlet  22 , thereby forming a single body of foam P. 
     As shown in FIG. 2, a machine compartment casing  30 , which defines a machine compartment, is also made of a synthetic resin through an injection molding process, a compressor and a condenser (not shown) being mounted within the machine compartment. In detail, when the machine compartment casing  30  is assembled together with the base plate  20 , the machine compartment casing  30  defines the machine compartment in the lower rear portion of the refrigerator. Since the compartment casing  30  is made of synthetic resin, the impact resistance of the machine compartment casing  30  is improved. 
     The base plate  20  has a plurality of fitting slits  24   a ,  24   b  and  24   c  on its top surface, while the machine compartment casing  30  has a plurality of fitting projections  32   a ,  32   b  and  32   c  at positions corresponding to the fitting slits  24   a ,  24   b  and  24   c . Consequently, when the machine compartment casing  30  is assembled together with the base plate  20 , the fitting projections  32   a ,  32   b  and  32   c  are fitted into the fitting slits  24   a ,  24   b  and  24   c , thus allowing the assembly of the base plate  20  and the machine compartment casing  30  to be easy. 
     In this embodiment, the machine compartment casing  30  is made of a synthetic resin material. However, it should be understood that the casing  30  may be made of metal without affecting the functioning of this invention. Of course, it should be also understood that such a machine compartment casing, made of metal, has the same construction as that described above. 
     According to this embodiment, the corners  34  of the machine compartment casing  30  are rounded off. By this, vortices are prevented in the machine compartment casing  30  when air flows into the machine compartment casing  30  so as to cool the compressor and the condenser in the machine compartment casing  30 , thereby helping air to flow smoothly through the machine compartment casing  30 . 
     The inner vertical edges  35   a  and  35   b  of the machine compartment casing  30  are shown to be sharp in FIG. 2, but are preferred to be rounded off. 
     The base plate  20  is provided with two fitting grooves  26   a  and  26   b  on its top surface, while the exterior casing  40  is provided with two fitting rails  40   a  and  40   b  on its lower edge. The base plate  20  and the external plate  40  are assembled together by, inserting the fitting rails  40   a  and  40   b  of the exterior casing  40  into the fitting grooves  26   a  and  26   b  of the base plate  20 . Consequently, the engagement structure allows the exterior casing  40  to easily be assembled with the base plate  20 . 
     The assembly process and the foaming process of the bottom structure for refrigerators, according to this embodiment, are described in the following. 
     As shown in FIGS. 2 and 3, the machine compartment casing  30  is assembled together with the base plate  20 . In such a case, the machine compartment casing  30  is fixed into the base plate  20  by engaging the fitting projections  32   a ,  32   b  and  32   c  of the machine compartment casing  30  into the fitting slits  24   a ,  24   b  and  24   c  of the base plate. 
     The exterior casing  40  is fixed into the base plate  20  while the machine compartment casing  30  is fixed into the base plate  20  . In the fixation of the exterior casing  40  into the base plate  20  the fitting rails  40 a and  40 b of the exterior casing  40  is engaged into the fitting grooves  26   a  and  26   b  of the base plate  20 . 
     The structure for mounting the internal casing  42  to the interior of the external casing  40  and the structure for mounting a back plate (not shown) over the machine compartment casing  30  coincides with the conventional, corresponding structures. If necessary to fix the internal plate  42  into the base plate  20 , the base plate  20  is provided with one or more fitting grooves on its top surface, while the internal plate  42  is provided with one or more fitting rails on its lower edge. 
     When the above-mentioned parts are all assembled together, the space between the exterior casing  40  and the interior casing  42  is filled with polyurethane foaming liquid. When the space between the exterior casing  40  and the interior casing  42  is filled with polyurethane foaming liquid, the interior of the base plate  20  is filled with the foaming liquid, so that the foam P is formed as shown in FIG.  3 . As described above, the interior of the base plate  20  is provided with the cavity  28  and the cavity  28  communicates, with the gap between the external and interior casing  40  and  42  through the foaming liquid inlet  22 . Therefore, it is natural that when the space between the exterior casing  40  and the interior casing  42  is filled with polyurethane foaming liquid, the cavity  28  of the base plate  20  is filled with the foaming liquid through the foaming liquid inlet  22 , thereby forming the foam P. 
     In FIG. 4, the base plate of the structure of a refrigerator according to another embodiment of the present invention is illustrated. When a heavy machine, such as a heavy compressor, is mounted at the base plate  20 , it is possible that a machine-seating portion of the base plate  20  is made of high strength metal and fixed to the remaining portion of the base plate  20  made of synthetic resin, thereby forming a complete base plate  20 . 
     The present invention has the following features. 
     The bottom of a refrigerator consists of a single piece of the base plate  20  made of synthetic resin. The interior of the base case plate  23  is provided with the cavity  28 , the cavity  28  being filled with an insulating material. The machine compartment casing  30 , which defines a machine compartment by being connected to the base plate  20 , may be selectively made of synthetic resin. 
     As shown in FIG. 4, it is possible to make a certain portion of the base plate  20  of metal. It is for improving the strength of the base plate  20  to make the portion of the base plate  20 . 
     Additionally, the base plate  20  is provided with the fitting grooves  26   a  and  26   b  and the fitting slits  24   a ,  24   b  and  24   c.    
     According to the present invention, the below mentioned effects are obtained. 
     In this invention, a single piece of a base plate constitutes the bottom of the refrigerator. Therefore, the strength of the bottom of the refrigerator is improved. In addition, since the weight of the bottom is lowered by making the base plate of synthetic resin, the transportation of the parts and manufactured products is easy. 
     The impact resistance of the base place is improved because the base plate of synthetic resin is not only made of synthetic resin, but has a cavity filled with synthetic resin. That is, the bottom structure of this invention absorbs external impact that is exerted to the structure during the transportation and the installation of the refrigerator. Since this improved impact resistance prevents the refrigerator from being damaged, the reliability of the refrigerator improves. 
     Further, since the bottom structure has easy and tight fitting constructions, the bottom structure is easily assembled and prevents the leakage of foaming liquid. 
     In the process of the injection molding of a machine compartment casing, the corners or edges of the machine compartment casing may be rounded off. This prevents vortices that are generated by airflow, the airflow entering the machine compartment casing so as to cool the compressor and the condenser installed in the machine compartment casing. By this, the noise of the refrigerator is minimized, while its heat dissipation effect is maximized. 
     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.