Patent Publication Number: US-7712852-B2

Title: Double drawer of refrigerator

Description:
BACKGROUND OF THE INVENTION 
   1. Field of Invention 
   The present invention relates to a drawer of a refrigerator, and more particularly, to a double drawer of a refrigerator comprising an auxiliary drawer having drawing rails which assist a main drawer for storing food to slide out and guide rails which assist the auxiliary drawer to slide out. 
   2. Description of the Prior Art 
   In general, a refrigerator is equipment for storing foods at a lower temperature. A refrigerator is used to store foods in a freezing or refrigerating state according to the foods to be stored therein. Cold air supplied into a refrigerator is produced by heat exchange with refrigerant. The refrigerant circulates in the refrigerator while undergoing a continuous refrigeration cycle of compression, condensation, expansion, and evaporation. Thus, the cold air produced by the heat exchange of the refrigerant is uniformly distributed into the refrigerator by means of the convection, thereby allowing foods in the refrigerator to be stored at a desired temperature. 
     FIG. 1  is a perspective view showing a refrigerator according to a prior art in a state where a drawer door is opened. As shown in the figure, a refrigerator main body  1  is shaped as a substantially rectangular hexahedron. Hinged doors  10  that can selectively open and close the right and left sides of the main body  1  are formed at an upper portion of the main body  1 , and a drawer door  12  that can slides in and out of the main body  1  in a fore and aft direction is formed at a lower portion of the main body  1 . 
   Although not shown in the figure, refrigerating and freezing chambers are formed in the refrigerator main body  1  in order to store various foods after freezing or refrigerating them. The interiors of the respective refrigerating and freezing chambers are provided with a variety of shelves, drawers, trays, and the like according to features of the various foods. 
   The temperature varies according to positions in the respective refrigerating and freezing chambers. The shelves, drawers, trays, and the like, which partition the respective inner spaces of the chambers, control the convection flow of the cold air in the main body  1 , and then make it possible to control the temperature according to a position. In a general refrigerator, since it is hard to deliver the cold air to the lower portion of the main body  1 , the temperature in the lower portion is relatively high. 
   In the meantime, a drawer chamber  20 , which slides in and out by the drawer door  12  and has an inner space for storing food, is provided in the lower portion of the refrigerator main body  1 . The drawer chamber  20 , in which meat, fish, or food necessary to be stored for a long time is stored, comprises a plurality of accommodation spaces with various dimensions in order to store a variety of foods from small to large size. 
   The drawer chamber  20  is provided with a storage box  30  for storing relatively large-sized food and a pull drawer  40  for storing foods relatively smaller than those stored in the storage box  30 . Among the foods necessary to be stored in a frozen state, the large-sized foods or the foods unnecessary to be divided are stored in the storage box  30 . 
   The storage box  30  is connected to the lower portion of the drawer door  12  through hinges, and thus slides out forward along with the drawer door  12  when the drawer door  12  is pulled forward. Therefore, a user can look at the inside of the storage box  30  only by pulling the drawer door  12  and allow the storage box  30  to slide in and out without an additional operation. 
   In addition, upper ends of both side surfaces of the storage box  30  are fixed to one sides of three-step-telescopic rails  50 , and the other sides of the rails  50  are fixed to both inside surfaces of the refrigerator main body  1 . Therefore, the storage box  30  cooperates with the drawer door  12  and can thus slide in and out while being guided by the rails  50 . 
   Meanwhile, the pull drawer  40  is installed in the upper portion of the storage box  30 . In detail with reference to  FIG. 2 , the pull drawer  40  is formed in a drawer shape by allowing a plurality of wires to be crossed and bent. 
   The upper portion of the pull drawer  40  is opened. A front plate  42 , which defines a partial front external appearance of the pull drawer  40 , is provided in the front of the pull drawer  40 . Rail mount brackets  44 , to which second movable rails  54 ″ to be mentioned below are fixed, are provided on the upper ends of both sides of the pull drawer  40 . 
   The pull drawer  40  is pulled and pushed while sliding in the fore and aft direction along the three-step-telescopic rails  50 , so that the user may store the desired foods. In addition, each of the rails  50  comprises a fixed rail  52  and a movable rail  54  sliding and moving in the fore and aft direction. 
   The fixed rails  52  are installed to horizontally extend on the insides of the refrigerator main body  1 , i.e., on the inside surfaces of the right and left side walls of the drawer chamber  20 , and serve to guide the slide of the movable rails  54 . 
   In more detail, when the movable rails  54  are mounted in the fixed rails  52 , rolling members provided on the movable rails  54  are brought into contact with surfaces of the fixed rails  52 , so that the movable rails  54  slide along the fixed rails  52 . 
   In the meantime, each of the movable rails  54  is composed of a first movable rail  54 ′ and a second movable rail  54 ″. The first movable rails  54 ′ are mounted to the fixed rails  52  and thus configured to slide forward along the fixed rails  52 , while the second movable rails  54 ″ are mounted to the first movable rails  54 ′ to slide forward along the first movable rails  54 ′. 
   At this time, the first movable rails  54 ′ and the second movable rails  54 ″ are provided with the rolling members. The rolling members roll in the fixed rails  52  for guiding the first movable rails  54 ′ and with the first movable rails  54 ′ for guiding the second movable rails  54 ″, respectively. 
   Since the second movable rails  54 ″ are fixed to the respective rail mount brackets  44 , the pull drawer  40  can slide in the fore and aft direction along the rails  50 . The extent that the pull drawer  40  slides out is determined according to an extended stroke of the rails  50 , so that the dimensions of the pull drawer  40  are determined. 
   However, the pull drawer of a refrigerator so configured has the following problems. 
   That is, when the rails  50  comprising the first movable rails  54 ′, the second movable rails  54 ″ and the fixed rails  52  are pulled out while they continuously slide collinearly, the conventional refrigerator pull drawer is subjected to a moment caused from the weight of the foods accommodated in the pull drawer  40  itself and the extended length of the rails  50 . 
   Therefore, when the extended length is large or many foods are accommodated, the moment exerted on the rails  50  is also increased, so that the rails  50  for supporting the pull drawer  40  are subjected to an excessive load. It causes the rails  50  to be damaged and raises a problem in that the rails  50  do not perform their inherent function. 
   In addition, when the moment is reduced by allowing the extended length to be decreased, the size of the pull drawer  40  is also reduced in proportion thereto. Accordingly, an amount of foods to be accommodated in the pull drawer  40  is decreased, which is ineffective. Further, since the inner space of the drawer chamber  20  in the rear of the pull drawer  40  cannot be available, there is a problem in that the practical usability of the inner storage space is deteriorated. 
   The rails  50  for causing the pull drawer  40  to slide comprise the first movable rails  54 ′, the second movable rails  54 ″ and the fixed rails  52 . The pull drawer  40  further comprises the rail mount brackets  44  for fixing the rails  50  to the pull drawer  40 . In addition, the rails  50  are formed of metallic material, while the rolling members mounted to the rails  50  are formed of the material different from the metal. 
   Therefore, the number of the components for operating the pull drawer  40  is unnecessarily increased, the kinds of the components are different from each other, and the manufacturing processes thereof are also different from each other, thus increasing the total man-hour needed for the works. Accordingly, there are problems in that the productivity is decreased as well as the production costs are increased. 
   In the meantime, the pull drawer  40  assembled to the rails  50  is installed all together to the drawer chamber  20 , and is configured such that the pull drawer  40  is not easily separated in order not to escape. Thus, since the assembly of the pull drawer  40  and the rails  50  should be entirely disassembled when the pull drawer  40  is separated in order to be cleaned, managed, or the like, many problems are raised in the maintenance and services. 
   Furthermore, since the sliding order of the first and second movable rails  54 ′ and  54 ″ is not determined when the pull drawer  40  moves in the fore and aft direction by means of the first movable rails  54 ′, the second movable rails  54 ″ and the fixed rails  52 , there is a problem in that much inconvenience is raised when using the pull drawer  40 . 
   The pull drawer  40  is guided by guide rails (not shown) provided on both side surfaces of the pull drawer  40 . When the pull drawer  40  is closed, the front end of the pull drawer  40  collides with the front end of the refrigerator. Thus, there is also a problem in that noises occur or the pull drawer  40  is damaged. 
   Since it is difficult to separate the rail  50  into parts since the movable rails  54 ′, the second movable rails  54 ″ and the fixed rails  52  are integrally assembled into the rails  50 , the installation position of the pull drawer  40  is fixed. Thus, it is impossible to control the layout in the drawer chamber  20  using the pull drawer  40 . Accordingly, there are also problems in that it is difficult to achieve flexible accommodation environments for accommodating a variety of foods in the drawer chamber  20  and that the space usability of the drawer chamber  20  is deteriorated. 
   SUMMARY OF THE INVENTION 
   Accordingly, the present invention is conceived to solve the aforementioned problems in the prior art. An object of the present invention is to provide a double drawer of a refrigerator, which comprises a main drawer, an auxiliary drawer having drawing rails which assist the main drawer to slide out, and guide rails assisting the auxiliary drawer to slide out, whereby a sufficient extended length can be secured, the space usability is improved, and the durability can also be improved in spite of its long extended length. 
   Another object of the present invention is to provide a double drawer of a refrigerator, which comprises a main drawer, an auxiliary drawer having drawing rails which assist the main drawer to slide out, and guide rails assisting the auxiliary drawer to slide out, whereby the double drawer can be easily cleaned or managed due to its easy assembly and disassembly. 
   A further object of the present invention is to provide a double drawer of a refrigerator, which comprises a main drawer, an auxiliary drawer, and guide rails, wherein the strength of the main drawer is considerably improved. 
   A still further object of the present invention is to provide a double drawer of a refrigerator, which comprises a main drawer, an auxiliary drawer, and guide rails, wherein the shock caused from the collision between the main drawer and the auxiliary drawer can be alleviated. 
   A still further object of the present invention is to provide a double drawer of a refrigerator, which comprises a main drawer, an auxiliary drawer, and guide rails, wherein the main drawer is detachably mounted to the auxiliary drawer and selectively mounted to upper and lower drawing rails of the auxiliary drawer, thereby considerably increasing the space efficiency in a refrigerator main body. 
   A still further object of the present invention is to provide a double drawer of a refrigerator, which comprises a main drawer, an auxiliary drawer, and guide rails, wherein the space usability of the auxiliary drawer can be considerably increased. 
   According to the present invention for achieving the objects, there is provided a double drawer of a refrigerator comprising a main drawer having a predetermined space defined therein for accommodating foods; an auxiliary drawer having an inner space therein for accommodating the main drawer, including drawing rails for guiding the main drawer to slide in a fore and aft direction and allowing the main drawer to slide in and out; and guide rails installed in a main body of the refrigerator to guide the auxiliary drawer to slide in the fore and aft direction. 
   According to an embodiment of the present invention, rolling members, which roll along the drawing rails, may be provided on both side surfaces of the main drawer to allow the main drawer to be smoothly slid. Depressed seating portions may be formed at both side ends of the drawing rail to allow the rolling member to be seated therein. More preferably, the seating portions are formed to limit a rolling motion of the rolling member and a resultant sliding motion of the main drawer against a predetermined sliding force which is applied to the main drawer or auxiliary drawer and determined to cause the auxiliary drawer to slide, whereby the main drawer and auxiliary drawer can be sequentially slid. 
   In addition, rolling members, which roll along the guide rails and allow the auxiliary drawer to slide smoothly, may be provided on both side surfaces of the auxiliary drawer. First rolling members, which roll along the drawing rails and allow the main drawer to be smoothly slid, may be provided on both side surfaces of the main drawer, and second rolling members, which roll along the guide rails and allow the auxiliary drawer to be smoothly slid, may be provided on both side surfaces of the auxiliary drawer. 
   Further, sliding guides, which are slidably mounted in the guide rails to guide the sliding motion of the auxiliary drawer, may be formed to protrude from both side walls of the auxiliary drawer. Preferably, rolling members are provided at positions corresponding to the sliding guides on both side surfaces of the auxiliary drawer, the rolling members rolling along the guide rails and causing the auxiliary drawer to slide smoothly. 
   The auxiliary drawer may be formed in a box shape with front and upper faces thereof opened. 
   The auxiliary drawer may be formed with one or more connection portions which connect both side walls of the auxiliary drawer to each other and are formed to traverse both the side walls of the auxiliary drawer. At this time, the connection portions may be formed in a rear surface of the auxiliary drawer or in a bottom surface of the auxiliary drawer. Further, the auxiliary drawer may be opened to all faces either except both side surfaces and the bottom surface or except both side surfaces and the rear surface. 
   The drawing rail may extend from a rear end of the auxiliary drawer to a front end of the auxiliary drawer and may be formed with a rolling member insertion opening which is opened forward for insertion of the rolling member to guide forward insertion of the main drawer. At this time, the drawing rail may be formed stepwise so that a bottom surface of an upper step portion thereof is positioned above a bottom surface of a lower step portion thereof. Preferably, the drawing rail comprises a movable portion extending from the rear end to a middle portion of the side wall of the auxiliary drawer to guide the movement of the rolling member; a vertical portion extending vertically upward at an extended end of the movable portion to prevent the main drawer from coming off; and an insertion portion extending from an upper end of the vertical portion of the auxiliary drawer to the front end of the side wall of the auxiliary drawer, the insertion portion being a passage for insertion of the rolling member. 
   The main drawer may be formed with a reinforcing rib for reinforcing the main drawer. A plurality of the reinforcing ribs may be formed on a bottom surface of the main drawer in a fore and aft direction thereof. The reinforcing rib may be formed to protrude downward from a bottom surface of the main drawer. A lower end of the reinforcing rib may slide on the auxiliary drawer while being brought into contact with the auxiliary drawer. 
   Preferably, a rolling member for allowing the auxiliary drawer to easily move in a fore and aft direction thereof and a sliding guide for guiding the auxiliary drawer to move in the fore and aft direction are provided on each side surface of the auxiliary drawer, and a receiving portion is formed on the guide rail in the fore and aft direction to receive both the rolling member and the sliding guide and to slidably guide the rolling member and the sliding guide. 
   At this time, the receiving portion and the sliding guide may be formed with a rail catching portion and a guide catching portion, respectively, which are formed in a shape corresponding to each other to be caught to each other. Particularly, the rail catching portion may be formed at a front end of the receiving portion. 
   Preferably, at least one of the main drawer and the auxiliary drawer is provided with a shock absorbing member for alleviating collision between the auxiliary drawer and the main drawer. Preferably, the shock absorbing member is formed at a front end of the auxiliary drawer. More preferably, the shock absorbing member is formed of an elastic material, particularly, a rubber material. 
   Preferably, each of the drawing rails includes an opening type drawing rail formed to be bored through each side wall of the auxiliary drawer, and sliding members are formed on both side surfaces of the main drawer to be fitting into and slid along the opening type drawing rails. At this time, the opening type drawing rail may be formed to extend from a rear end at least to a middle portion of the auxiliary drawer. Further, seating portions are formed to be depressed downward at both side ends of each opening type drawing rail, each seating portion being somewhat larger than the sliding member. Preferably, the seating portions are formed to limit a sliding motion of the sliding member and the main drawer against a predetermined sliding force applied to the main drawer or auxiliary drawer, the force being determined to cause the auxiliary drawer to slide, whereby the main drawer and the auxiliary drawer can be sequentially slid. An insertion portion, which is a passage for insertion of the sliding member, may be formed to be opened upward at the rear end of the drawing rail. 
   The double drawer further comprises auxiliary rails formed in the refrigerator main body to guide the sliding motion of the main drawer separated from the auxiliary drawer. At this time, the main drawer may be selectively separated from the auxiliary drawer and mounted to the auxiliary rails, and an auxiliary drawer door may be provided on the auxiliary drawer to selectively close a face of the auxiliary drawer, thereby defining an additional accommodating space in the auxiliary drawer. 
   The auxiliary drawer may further comprise door guides in which the auxiliary drawer door is accommodated to guide a forward sliding motion of the auxiliary drawer door. Preferably, the auxiliary drawer door slides out forward and pivots upward when the auxiliary drawer is closed and is mounted on a bottom surface of the auxiliary drawer when the auxiliary drawer is opened. 
   Preferably, the drawing rails comprise upper drawing rails and lower drawing rails, and the main drawer is selectively mounted on the upper drawing rails and lower drawing rails. At this time, rolling members or sliding members capable of rolling along the upper drawing rails or lower drawing rails while being brought into contact with the drawing rails may be provided on both side surfaces of the main drawer. Further preferably, upper insertion portions, each of which is a passage for insertion of the rolling member or sliding member, are formed at rear ends of the upper drawing rails, and lower insertion portions, each of which is another passage for insertion of the rolling member or sliding member, are formed at front ends of the lower drawing rails. More preferably, the lower drawing rails are formed to extend from a front end of the side wall to a rear end of the side walls of the auxiliary drawer. 
   The auxiliary drawer may further comprise a partition for partitioning an inner space of the auxiliary drawer. At this time, a length between front and rear ends on a floor surface of the main drawer may be equal to or slightly larger than a length from a front end of a floor surface of the auxiliary drawer to the partition. In addition, the drawing rails may be formed to extend from positions, at which the partition is formed, to front ends of both side walls of the auxiliary drawer. More preferably, a front end of each of the drawing rails is opened and defines an insertion opening that is a passage for insertion of the rolling member or sliding member provided on both the side surfaces of the main drawer. Still more preferably, catching portions are formed on the drawing rails to protrude upward, thereby preventing the rolling member or sliding member provided on both side surfaces of the main drawer from sliding out. 
   The drawing rails and the rolling members may be formed of the same material. Alternatively, the guide rails and the rolling members may be formed of the same material. Preferably, the main drawer, the auxiliary drawer and the guide rails are injection molded. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features and advantages of the present invention will become apparent from the following description of preferred embodiments given in conjunction with the accompanying drawings, in which: 
       FIG. 1  is a perspective view showing a refrigerator according to a prior art in a state where a drawer door is opened; 
       FIG. 2  is a partial perspective view showing a pull drawer of the refrigerator according to the prior art; 
       FIG. 3  is a perspective view showing a refrigerator, in which a double drawer according to the present invention is employed, in a state where doors are opened; 
       FIG. 4  is an exploded perspective view showing a refrigerator double drawer according to a first embodiment of the present invention; 
       FIG. 5  is a perspective view showing that the refrigerator double drawer shown in  FIG. 4  slides in; 
       FIG. 6  is a perspective view showing the refrigerator double drawer shown in  FIGS. 4 and 5  where an auxiliary drawer slides out; 
       FIG. 7  is a perspective view showing the refrigerator double drawer shown in  FIGS. 4 and 5  where the auxiliary drawer and a main drawer slide out together; 
       FIGS. 8 to 11  are sectional views sequentially showing that the auxiliary and main drawers slide out in order to explain the operation of the refrigerator double drawer shown in  FIGS. 4 to 7 ; 
       FIG. 12  is an exploded perspective view showing a refrigerator double drawer according to a second embodiment of the present invention; 
       FIG. 13  is a perspective view separately showing an auxiliary drawer separated from the refrigerator double drawer shown in  FIG. 12 ; 
       FIG. 14  is a perspective view showing a modified embodiment in which the configuration of the auxiliary drawer of the refrigerator double drawer shown in  FIGS. 12 and 13  is changed; 
       FIG. 15  is an exploded perspective view showing a refrigerator double drawer according to a third embodiment of the present invention in which a main drawer can be mounted from a front end of an auxiliary drawer; 
       FIG. 16  is a perspective view separately showing the auxiliary drawer separated from the refrigerator double drawer shown in  FIG. 15 ; 
       FIGS. 17 and 18  are sectional views for explaining the operation of the refrigerator double drawer shown in  FIGS. 15  and  FIG. 16 ; 
       FIG. 19  is a perspective view showing the bottom of a main drawer separated from a refrigerator double drawer according to a fourth embodiment of the present invention; 
       FIG. 20  is an exploded perspective view showing a refrigerator double drawer according to a fifth embodiment of the present invention which has a configuration for mitigating collision between an auxiliary drawer and a main drawer; 
       FIGS. 21 and 22  are sectional views for explaining the operation of the refrigerator double drawer shown in  FIG. 20 ; 
       FIG. 23  is an exploded perspective view showing a refrigerator double drawer according to a sixth embodiment of the present invention; 
       FIG. 24  is a perspective view showing an auxiliary drawer separated from the refrigerator double drawer shown in  FIG. 23 ; 
       FIG. 25  is a sectional view for explaining the operation of the refrigerator double drawer shown in  FIGS. 23 and 24 ; 
       FIG. 26  is an exploded perspective view showing a refrigerator double drawer according to a seventh embodiment of the present invention; 
       FIG. 27  is a perspective view showing a bottom of an auxiliary drawer separated from the refrigerator double drawer shown in  FIG. 26 ; 
       FIG. 28  is a partial side view showing the auxiliary drawer separated from the refrigerator double drawer shown in  FIG. 26  wherein invisible portions are represented by dotted lines; 
       FIGS. 29 and 30  are perspective views showing a refrigerator in which the refrigerator double drawer shown in  FIG. 26  is employed, wherein the auxiliary drawer is installed in different positions; 
       FIG. 31  is an exploded perspective view showing a refrigerator double drawer according to an eighth embodiment of the present invention, in which the installation position of an auxiliary drawer is variously changed; 
       FIG. 32  is a perspective view showing the auxiliary drawer separated from the refrigerator double drawer shown in  FIG. 31 ; 
       FIGS. 33 and 34  are sectional views for explaining the operation of the refrigerator double drawer shown in  FIGS. 31 and 32 ; 
       FIG. 35  is an exploded perspective view showing a refrigerator double drawer according to a ninth embodiment of the present invention, which comprises an auxiliary drawer having a partition; 
       FIG. 36  is a perspective view showing the auxiliary drawer separated from the refrigerator double drawer shown in  FIG. 35 ; and 
       FIG. 37  is a sectional view for explaining the operation of the refrigerator double drawer shown in  FIGS. 35 and 36   
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Hereinafter, a variety of embodiments according to the present invention will be described. When the embodiments are described, like reference numerals will be used to designate like elements and the repeated descriptions will be omitted for the brevity of the specification. 
     FIG. 3  is a perspective view showing a refrigerator, in which a double drawer according to the present invention is employed, in a state where doors are opened to show the refrigerator double drawer. As shown in the figure, a refrigerator main body  100  comprises a refrigerating chamber  200  and a drawer chamber  300 . 
   The refrigerating chamber  200  is formed on an upper portion of the main body  100  and partitioned into two portions of the left and right sides. In order to effectively accommodate various kinds of foods, trays, shelves and drawers of various shapes are installed in the refrigerating chamber  200  and partition the inner space thereof. 
   Therefore, the stream of the cold air supplied from a side of the main body  100  is influenced by the trays, shelves and drawers, and thus, the convection flow is limited and controlled. A user can accommodate and store the foods in appropriate positions according to properties of the temperature due to the difference of the cold air supply. 
   In the meantime, hinged doors  220  for opening and closing the refrigerating chamber  200  in the upper portion of the main body  100  are provided on the left and right sides of the main body  100 . The respective hinged doors  220  are installed to be pivotable outward at both side ends of the main body  100  through hinged joint. 
   Thus, the respective hinged doors  220  individually close the left and right sides of the refrigerating chamber  200 , so that the independent spaces are defined. If desired, any one side of the refrigerating chamber  200  may be used as a freezing chamber. 
   In the meantime, the drawer chamber  300  is formed in the lower portion of the main body  100  in which the refrigerating chamber  200  is provided. The drawer chamber  300  in the form of a drawer, which defines a storage space capable of being pulled and pushed, is generally used as a freezing chamber. The drawer chamber  300 , in which fish, meat or food necessary to be stored for a long time is stored after frozen, is provided with an additional cold air supply hole, thus having a powerful freezing capability. 
   Further, the drawer chamber  300  may be used exclusively as a refrigerating chamber instead of a freezing chamber. At this time, the storage space of the drawer chamber  300  is formed to be wider, so that fruit, vegetable or relatively large or heavy food, which is difficult to be put in a container will be able to be stored. 
   A drawer door  320  for closing the inside of the drawer chamber  300  is formed in the front of the drawer chamber  300 . A lower end of the drawer door  320  is hingedly connected to a lower end of a storage box  340  for storing foods. The storage box  340  is mounted with three-step-telescopic rails  360 , which slide and extend in the fore and aft direction. 
   One side of each three-step-telescopic rail  360  is fixed to each inside surface of both walls of the drawer chamber  300 , so that the storage box  340  can slide along the three-step-telescopic rails  360  in the fore and aft direction. By pulling and pushing a handle formed on an upper portion of the drawer door  320 , the storage box  340  and the drawer door  320  slide in and out together. 
   In the meantime, an upper portion of the drawer chamber  300  is partitioned into right and left sides, wherein an ice machine for automatically making ice and storing the ice therein is provided on the left side and a double drawer  400  for storing the foods somewhat small to be stored in the storage box  340  or necessary to be separately stored is provided on the right side. 
     FIG. 4  is an exploded perspective view showing a refrigerator double drawer according to a first embodiment of the present invention;  FIG. 5  is a perspective view showing a state where the refrigerator double drawer according to the embodiment of the present invention is closed;  FIG. 6  is a perspective view showing the refrigerator double drawer in a state where an auxiliary drawer slides out; and  FIG. 7  is a perspective view showing the refrigerator double drawer in a state where the auxiliary drawer and a main drawer slide out together. 
   As shown in  FIGS. 4 to 7 , the double drawer  400  comprises guide rails  420 , an auxiliary drawer  440 , and a main drawer  460 . Here, first rolling members  462  are provided on both side surfaces of the main drawer  460  which is provided for accommodating and storing food, while second rolling members  442  are provided on both side surfaces of the auxiliary drawer  440  which allows the main drawer  460  to slide in a state where the main drawer  460  is accommodated in the auxiliary drawer  440 . In addition, the guide rails  420  are installed to the refrigerator main body in order to slidably guide the auxiliary drawer  440  in which the main drawer  460  is accommodated. 
   The guide rails  420 , which guide the auxiliary drawer  440  to slide in and out, extend horizontally and are installed in the refrigerator main body  100 . The guide rails  420  are formed with receiving portions  422  for guiding the rolling of the second rolling members  442 , respectively. The receiving portions  422 , which receive the second rolling members  442  installed on the auxiliary drawer  440 , are longitudinally formed with a predetermined width along the substantially middle portions of the guide rails  420 . 
   Each of the second rolling members  442  includes the member for providing the smooth slide, such as a roller or bearing. When a roller is used as the second rolling member  442 , it is possible to form a roller of the same material as the auxiliary drawer  440 . 
   The receiving portion  422  is defined by a protrusion  424  of “⊃” shape (as viewed from the side) in the peripheral portion of the receiving portion  422 . The protrusion  424  is formed to protrude by a predetermined height so that the second rolling member  442  is received in the receiving portion  422  and to have a front upper corner opened so that the second rolling member  442  is inserted into the receiving portion  422  from the front. 
   In addition, a rail catching portion  426  is formed on the lower front end of the protrusion  424  to somewhat protrude upward as viewed from the side. The rail catching portion  426  protrudes to have its end of a substantially hook shape. 
   The guide rails  420  are installed on the inside of the refrigerator main body  100 , more particularly, at corresponding positions of left and right upper wall surfaces of the inside of the drawer chamber  300  (see  FIG. 3 ). Further, the auxiliary drawer  440  is slidably mounted to the guide rails  420 . 
   The auxiliary drawer  440  is formed in a hexahedral box shape with the front, upper and rear portions opened. The second rolling members  442  are provided on upper rear portions of both side surfaces of the auxiliary drawer  440 . The second rolling members  442 , which roll on portions of the receiving portions  422 , cause the auxiliary drawer  440  to slide along the guide rails  420 . 
   In addition, sliding guides  444  are formed on upper portions of both the side surfaces of the auxiliary drawer  440  to which the second rolling members  442  are mounted. The sliding guides  444 , which prevent the auxiliary drawer  440  from sagging downward when the auxiliary drawer  440  slides out forward along the guide rails  420 , protrude to have a shape similar to the receiving portions  422  so as to be supported on the protrusions  424  formed on that the guide rails  420 . 
   The sliding guides  444  are formed to extend from the portions, where the second rolling members  442  are installed, to the front end of the auxiliary drawer  440 . Guide catching portions  446  are formed on the sliding guides  444  at the portions adjacent to the second rolling members  442   
   The guide catching portions  446 , which are formed to protrude downward to have a shape similar to the rail catching portions  426 , are brought into contact with the rail catching portions  426 , thus causing the auxiliary drawer  440  no more to slide out. Furthermore, the guide catching portions  446  serve to cause the main drawer  460  to slide out sequentially after the auxiliary drawer  440  slides out, as described below in detail. 
   In the meantime, drawing rails  450  are formed on both side walls of the auxiliary drawer  440 . The drawing rails  450 , which enable the main drawer  460  to slide in the fore and aft direction, receive the first rolling members  462  installed to the main drawer  460 . 
   The drawing rails  450  are formed below the sliding guides  444  by allowing portions of the auxiliary drawer  440  to be depressed from the inside to the outside thereof by a predetermined width, and extend from the rear ends of both the side walls of the auxiliary drawer  440  up to substantially center portions thereof. 
   As viewed from the side, an end of each drawing rail  450  is formed round, and seating portions  452  are formed on lower portions of both ends of the drawing rail  450 . The seating portions  452 , which are depressed downward with a predetermined curvature, function as temporary catching portions when the first rolling members  462  mounted to the drawing rails  450  are seated in the seating portions  452 . 
   In the meantime, as viewed from the side, the other end of each drawing rail  450 , which is at a rear end side of the auxiliary drawer  440 , extends vertically upward, wherein an extended end is opened. Therefore, the first rolling members  462  mounted to the main drawer  460 , which will be described below, may be downward inserted into the drawing rails  450  of the auxiliary drawer  440  through the rear ends thereof. 
   Further, the rear face of the auxiliary drawer  440  is formed with a substantially upper half portion opened, thus making it possible to easily insert the main drawer  460  into the drawing rails  450  and causing the drawing rails  450  not to influence the guide rails  420 . 
   The main drawer  460  is seated in the auxiliary drawer  440 . The main drawer  460 , in which foods are stored, is formed in a box shape with the upper portion being opened and is generally formed somewhat smaller than the auxiliary drawer  440  to be seated in the auxiliary drawer  440 . 
   Further, in order for the external appearance of the main drawer  460  to look better when it is seated in the auxiliary drawer  440 , edges of the main drawer  460  except its rear portion are outward bent at a right angle. 
   A front plate  464  defining a front external appearance of the main drawer  460  is formed on the front of the main drawer  460 . The front plate  464  functions as a handle when the user intends to pull the main drawer  460 . 
   The first rolling members  462  of the main drawer  460  are formed to have the same shape as the aforementioned second rolling members. The first rolling members  462  are accommodated in the drawing rails  450  and roll in the drawing rails  450 . The first rolling members  462  assist the main drawer  460  to smoothly slide in the auxiliary drawer  440 . 
   The first rolling members  462  are installed to substantially middle portions of the rear sides of both the side surfaces of the main drawer  460 , i.e., at positions corresponding to those where the drawing rails  450  are formed. That is, the first rolling members  462  are installed so that they can be received in the drawing rails  450  smoothly when the main drawer  460  is seated in the auxiliary drawer  440 . 
   Each of the first rolling members  462  includes the member for providing the smooth slide, such as a roller or bearing. When a roller is used as the first rolling member  462 , it is possible to form a roller of the same material as the main drawer  460 . In addition, cold air inlets  466  are further formed in the rear wall of the main drawer  460  in order for the cold air supplied from the rear portion thereof to flow in the main drawer  460  smoothly. 
   In the meantime, the main drawer  460 , the auxiliary drawer  440 , and the guide rails  420  are formed of the same material, for example, by injection molding the material such as plastic. 
     FIGS. 8 to 11  are sectional views showing how the aforementioned refrigerator double drawer is used. Referring to  FIGS. 8 to 11 , the operation of the refrigerator double drawer according to the present embodiment will be described as follows. 
   A state where the double drawer  400  is accommodated in the refrigerator will be first discussed. As shown in  FIG. 8 , the main drawer  460  is accommodated in the auxiliary drawer  440  and the rear surfaces of the main and auxiliary drawers  460  and  440  are in contact with each other. The second rolling members  442  of the auxiliary drawer  440  are positioned at the rear ends of the guide rails  420 , while the first rolling members  462  of the main drawer  460  are positioned at the rear ends of the drawing rails  450  formed on the auxiliary drawer  440 . Therefore, the main drawer  460  except a portion of the front wall thereof is fully accommodated in the auxiliary drawer  440 , and the guide rails  420  are positioned on both the side surfaces of the auxiliary drawer  440 . 
   In order to store or take out the foods in the double drawer  400  installed the drawer chamber  300  of the refrigerator in a state where the double drawer  400  is accommodated in the refrigerator as above, the user grips a handle formed on the drawer door  320  and then pulls out the drawer door  320  forward. When the drawer chamber  300  is opened as above, the storage box  340  is completely exposed to the outside. At this time, the double drawer  400  provided above the storage box  340  is in a state where it is accommodated in the refrigerator as shown in  FIGS. 3   
   As shown in  FIGS. 8 and 9 , when the front plate  464  is gripped by hand and pulled forward, the auxiliary drawer  440  slides out along the guide rails  420  from the position shown in  FIG. 8  to the position shown in  FIG. 9 . In such a process, the second rolling members  442  of the auxiliary drawer  440  roll on portions of the receiving portions  422  of the guide rails  420 . The rolling of the second rolling members  442  assists the auxiliary drawer  440  to slide and be pulled smoothly. 
   At this time, when the auxiliary drawer  440  initially slides out, the main drawer  460  slide out before the auxiliary drawer  440  slides or does not slide out at the same time when the auxiliary drawer  440  slides. The reason is that since the first rolling members  462  are seated in the seating portions  452  formed on the rear ends of both the side walls of the drawing rails  450 , a relatively large force is required to allow the first rolling members  462  to roll against the seating portions  452 . 
   On the other hand, although the rear ends of the guide rails  420 , in which the second rolling members  442  roll, are formed at an inclined angle, since a force for causing the second rolling members  442  to ascend the inclination is relatively smaller than that for causing the first rolling members  462  to go over the seating portions  452 , the auxiliary drawer  440  first slides out when the front plate  464  is slowly pulled. 
   When the user grips the front plate  464  and pulls it slowly forward, the guide catching portions  446  formed on the auxiliary drawer  440  and the rail catching portions  426  formed on the guide rails  420  are finally brought into contact with and caught to each other. Thus, the auxiliary drawer  440  no more slides out. The position in which the auxiliary drawer  440  no more slides out as above is well shown in  FIG. 9 . 
   As shown in  FIGS. 9 and 10 , if the user pulls the main drawer  460  continuously after the guide catching portions  446  and the rail catching portions  426  are brought into contact with each other, the force for causing the first rolling members  462  to go over the seating portions  452  occurs, so that the first rolling members  462  roll on portions of the drawing rails  450 . 
   Due to the rolling of the first rolling members  462 , the main drawer  460  slides out forward from the inside of the auxiliary drawer  440 . If the main drawer  460  is continuously pulled out, the first rolling members  462  are seated in the seating portions  452  positioned at the front of the drawing rails  450 , the pulling of the main drawer  460  no more progresses. The position in which the main drawer  460  is completely pulled is well shown in  FIG. 10 . 
   When the main drawer  460  completely slides out from the auxiliary drawer  440 , the main drawer  460  is exposed from the inside to the outside of the drawer chamber  300  of the refrigerator. At this time, the user may put or take foods in or out of the double drawer  400  (See  FIG. 3 ). 
   In the meantime, when the front plate  464  of the main drawer  460  is pushed in order to slide in the double drawer  400 , due to the operation of the seating portions  452 , the auxiliary drawer  440  first slides in while the second rolling members  442  roll from the position shown in  FIG. 10  to the position shown in  FIG. 11 , and subsequently, the main drawer slides in by turns, in the same manner as the double drawer  400  slides out. When the main drawer  460  completely slides in and is thus returned to its initial position shown in  FIG. 8 , the drawer chamber  300  is closed by pushing the aforementioned drawer door  320  (see  FIG. 3 ). 
   In the meantime, in order to disassemble the double drawer  400  for cleaning or other reasons, the auxiliary drawer  440  in which the main drawer  460  is seated is dismounted from the open front portions of the guide rails  420  by lifting the auxiliary drawer  440  and simultaneously pulling it forward. 
   Next, by lifting the main drawer  460  after the first rolling members  462  are positioned at the rear ends of the drawing rails  450  by pushing the main drawer  460  to the rear of the auxiliary drawer  440 , the first rolling members  462  are pulled out of the open portions of the drawing rails  450  and then the main drawer  460  is disassembled. In order to intend the disassembled double drawer  400  to be mounted again, the double drawer  400  is assembled in reverse order of the disassembly. 
     FIGS. 12 to 14  are views showing a refrigerator double drawer  400  according to a second embodiment of the present invention with an auxiliary drawer  440  lightened. 
   Referring to  FIGS. 12 and 13 , the auxiliary drawer  440  has a width larger than the main drawer  460  and thus the main drawer  460  is accommodated in the auxiliary drawer  440 , while both the side surfaces of the auxiliary drawer  440  face the guide rails  420 . In the same manner as the previous embodiment, since the front face of the auxiliary drawer  440  is completely opened, the main drawer  460  seated in the auxiliary drawer  440  is caused to slide smoothly forward. Since the upper and rear faces of the auxiliary drawer  440  are also opened, the main drawer  460  is caused to be downward mounted in the auxiliary drawer  440 . 
   Contrary to the previous embodiment, however, the auxiliary drawer  440  of the present embodiment is formed so that a considerable portion of its bottom face is opened. The open portion of the bottom face of the auxiliary drawer  440  is formed with connection portions  443  which connect both side walls of the auxiliary drawer  440  to each other. The connection portions  443  are formed to horizontally traverse the bottom face of the auxiliary drawer  440  and support both the side walls of the auxiliary drawer  440  by connecting the lower ends of both the side walls of the auxiliary drawer  440  to each other. 
   Therefore, the connection portions  443  cause the auxiliary drawer  440  to be lightened in configuration, and the friction between the main drawer  460  and the bottom face of the auxiliary drawer  440  can be minimized when the main drawer  460  slides in and out. One or more connection portions  443  may be formed, if desired, and a width of each connection portion can be diversely changed according to conditions. 
     FIG. 14  shows an auxiliary drawer  440  according to a modification to the embodiment shown in  FIGS. 12 and 13 . As shown in  FIG. 14 , the auxiliary drawer  440  of the modification has the same configuration of both the side walls as the auxiliary drawer of the previous embodiment. However, the auxiliary drawer  440  is configured so that the bottom face as well as the front and upper faces thereof is opened and both the side walls of the auxiliary drawer  440  are connected to each other through connection portions  443  formed in the rear face of the auxiliary drawer  440 . Therefore, both the side walls of the auxiliary drawer  440  are supported by the connection portions  443  and maintain the configuration of the auxiliary drawer  440  for the main drawer  460  to slide stably in the auxiliary drawer  440 . 
     FIGS. 15 to 18  are views showing a refrigerator double drawer according to a third embodiment of the present invention in which a main drawer is inserted into an auxiliary drawer from the front thereof and slides. As shown in  FIGS. 15 to 18 , the refrigerator double drawer of the present embodiment comprises guide rails  420 , an auxiliary drawer  440 , and a main drawer  460  in the same manner as the previous embodiments. 
   Referring to  FIGS. 15 to 18 , drawing rails  450  are formed on both side walls of the auxiliary drawer. The drawing rails  450 , which first rolling members  462  provided on both side surfaces of the main drawer  460  are in contact with and roll in, are formed by allowing portions of the auxiliary drawer  440  to be depressed from the inside to the outside thereof by a predetermined depth. 
   Each of the drawing rails  450  is formed to extend from a rear end of the auxiliary drawer  440  to a front end of the auxiliary drawer  440  and is formed stepwise so that a bottom surface of an upper step portion thereof is positioned above a bottom surface of a lower step portion thereof. 
   In addition, in order to receive the first rolling members  462 , the drawing rails  450  are formed at positions corresponding to the first rolling members  462  when the main drawer  460  is seated in the auxiliary drawer  440 . 
   The drawing rail  450  comprises a movable portion  453  for guiding the movement of the first rolling member  462 , a vertical portion  455  functioning as a catching portion for catching the first rolling member  462 , and an insertion portion  457  in which the first rolling member  462  is inserted. 
   The movable portion  453  is formed to extend in parallel with the bottom surface of the auxiliary drawer  440  from the rear end to the middle portion of the auxiliary drawer  440  and to have depth and width sufficient for the first rolling member  462  to move smoothly. 
   Seating portions  452  are formed in both side ends of the movable portion  453 . The seating portions  452 , in which the first rolling member  462  is seated when the main drawer  460  completely slides out forward from the inside of the auxiliary drawer  440  or completely slides in rearward, are formed to be depressed with a predetermined curvature. 
   The vertical portion  455  is formed to vertically extend upward at the front end of the movable portion  453 . The vertical portion  455  functions as a catching portion which prevents the first rolling member  462  from escaping out of the movable portion  453  when the main drawer  460  slides out. It is preferred that an extended height of the vertical portion  455  be at least larger than a radius of the first rolling member  462 . 
   The insertion portion  457  is formed at the upper end of the vertical portion  455  which is formed to extend by the predetermined height. The insertion portion  457 , which is a passage for insertion of the first rolling member  462 , is formed to extend from the upper end of the vertical portion  455  to the front end of the auxiliary drawer  440 . 
   In addition, the front end of the insertion portion  457  is opened to the front, so that a rolling member insertion opening  457 ′ is defined, into which the first rolling member  462  can be inserted when the main drawer  460  is seated in the auxiliary drawer  440 . 
   The rolling member insertion opening  457 ′ is opened to be somewhat larger than a diameter of the first rolling member  462 . Thus, the main drawer  460  is seated in the auxiliary drawer  440  by inserting the first rolling members  462  into the insertion portions  457  of the drawing rails  450  through the rolling member insertion openings  457 ′. 
   In the meantime, second rolling members  442  are provided on both side surfaces of the auxiliary drawer  440  to which the drawing rails  450  are mounted. The second rolling members  442 , which cause the auxiliary drawer  440  to slide along guide rails  420 , which will be described below, have the same configuration as the first rolling members  462 . 
   The second rolling members  442  are mounted on upper rear portions of both the side surfaces of the auxiliary drawer  440 , i.e., above the drawing rails  450 , respectively. In addition, sliding guides  444  are formed to extend from the positions, in which the second rolling members  442  are mounted, to the front ends of the auxiliary drawer  440 . 
   The sliding guides  444 , which serve to prevent the auxiliary drawer  440  from sagging when the auxiliary drawer  440  slides in and out, are formed to protrude outward with a predetermined width. Guide catching portions  446  are formed on the rear portions of the sliding guides  444 , more particularly, adjacent to the positions in which the second rolling members  442  are mounted. 
   The guide catching portions  446  are brought into contact with rail catching portions  426  formed on the guide rails  420  and then limit the sliding motion of the auxiliary drawer  440 , so that the auxiliary drawer  440  cannot come off due to an excessive pulling action when the auxiliary drawer  440  slides out. To this end, each guide catching portion  446  is formed to protrude in a hook shape on the lower portion of each sliding guide  444 . 
   In the meantime, the auxiliary drawer  440  is mounted to the guide rails  420 . The guide rails  420 , which serve to guide the slide of the auxiliary drawer  440 , are installed on the left and light sides of the refrigerator main body  100  (see  FIG. 3 ), more particularly, on the left and light side surfaces of the upper portion of the drawer chamber  300 . 
   Each of the guide rails  420  is formed in an elongated quadrangular plate shape. A protrusion  424  and a receiving portion  422  are formed on the middle portion of each guide rail  420  to extend along the longitudinal direction of the guide rail  420 . 
   The protrusion  424  is formed along the peripheral portion of the guide rail  420  to protrude inward by a predetermined distance with a predetermined width. Therefore, the receiving portion  422  is naturally formed to be depressed in the inside of the portion in which the protrusion  424  is formed. The configuration of the receiving portion  422  is determined according to the protrusion  424 . 
   The receiving portion  422 , which the second rolling member  442  is in contact with and rolls in, is formed with a predetermined width so that the second rolling member  442  stably rolls and moves. 
   In addition, the protrusion  424  is formed to have a front upper corner opened. The rail catching portion  426  is formed at the front end of the lower portion of the protrusion  424 . The rail catching portions  426  are brought into contact with the guide catching portions  446  formed on the sliding guides  444  and prevent the auxiliary drawer  440  from sliding out excessively. Each rail catching portion  426  is formed to protrude upward in a hook shape like the guide catching portion  446 . 
   Hereinafter, the operation of the double drawer  400  of a refrigerator according to the present invention so configured will be described. 
     FIG. 18  is a schematic view illustrating the operation of the aforementioned refrigerator double drawer. Referring to the figure, in a state where the double drawer  400  is completely accommodated in the refrigerator, the first rolling members  462  of the main drawer  460  are seated in the drawing rails  450 , more particularly, in the seating portions  452  at the rear ends of the movable portions  453  of the drawing rails  450 , and the second rolling members  442  of the auxiliary drawer  440  are positioned at the rear ends of the guide rails  420 . 
   In order to pull the double drawer  400 , when the front plate  464  formed on the front of the main drawer  460  is gripped and pulled forward, the auxiliary drawer  440  first slides out forward. 
   At this time, the main drawer  460  does not slide out before the auxiliary drawer  440 . It is the reason why the first rolling members  462  causing the main drawer  460  to slide are seated in the seating portions  452  at the rear ends of the movable portions  453  and a predetermined force is required to cause the first rolling members  462  to go over the seating portions  452  and move. 
   On the other hand, the second rolling members  442  that allows the auxiliary drawer  440  to slide are positioned at the rear ends of the receiving portions  422  of the guide rails  420 . Further, although the rear ends of the receiving portions  422  are somewhat inclined, the second rolling members  442  can go over the inclinations with a force smaller than a force needed for allowing the first rolling members  462  to go over the seating portions  452 . Thus, the auxiliary drawer  440  first slides out. 
   When the guide catching portions  446  come into contact with the rail catching portions  426  after the auxiliary drawer  440  slides out to a certain extent, the auxiliary drawer  440  does not slides out any longer. When a force for pulling the main drawer  460  forward becomes larger than that for causing the first rolling members  462  to go over the seating portions  452  by continuously pulling the front plate  464 , the first rolling members  462  go over the seating portions  452  and then move along the movable portions  453 . 
   The movement of the first rolling members  462  causes the main drawer  460  to slide out forward from the inside of the auxiliary drawer  440  while the first rolling members  462  are guided by the movable portions  453 . When the first rolling members  462  are positioned at the seating portions  452  in the front ends of the movable portions  453 , the main drawer  460  no more slides out. 
   In the meantime, upon review of the process of sliding in the double drawer  400 , when the front plate  464  of the main drawer  460  is pushed rearward, the seating portions  452  at the front ends of the movable portions  453  cause the second rolling members  442  mounted to the auxiliary drawer  440  to roll and move first in the same manner as the double drawer  400  slides out. 
   When the movement of the second rolling members  442  is completed, the first rolling members  462  go over the seating portions  452  and move rearward along the movable portions  453 . Thus, the main drawer  460  slides in rearward. When the main drawer  460  completely slides in, the double drawer  400  is returned to its initial position before it slides out. 
   In the meantime, when services of the double drawer  400  are needed or the main drawer  460  in which foods are accommodated is necessary to be disassembled together during use of the double drawer  400 , the front plate  464  is pulled out through the aforementioned pulling process so that the main drawer  460  moves to the front ends of the movable portions  453 . 
   Then, in order for the first rolling members  462  to pass over the vertical portions  455 , if the first rolling members  462  are positioned at the rear ends of the insertion portions  457  after the main drawer  460  is lifted by a predetermined height, the main drawer  460  is separated from the auxiliary drawer  440  by pulling the main drawer  460  forward again to pass through the rolling member insertion openings  457 ′. 
   In order to mount the separated main drawer  460  to the auxiliary drawer  440 , in reverse order of the disassembly, by inserting the first rolling members  462  into the rolling member insertion openings  457 ′, allowing the first rolling members  462  to pass through the insertion portions  457  and the vertical portions  455 , and then causing the double drawer  400  to slide in, the double drawer  400  is assembled to its initial state. 
   The refrigerator double drawer  400  of the aforementioned present embodiment, when the double drawer is intended to be cleaned or managed or the main drawer, in which foods are accommodated, is intended to be pulled out at a time, there are advantages in that it is possible to easily separate the main drawer  460  through the front of the auxiliary drawer  440  as well as to easily assemble the main drawer  460  by inserting it through the front of the auxiliary drawer  440  even when mounting the main drawer  460  after separating it, thus causing the user to conveniently use the main drawer  460 . 
     FIG. 19  is a perspective view showing a bottom of a main drawer  460  according to a fourth embodiment of the present invention in order to explain the main drawer  460  the strength of which is considerably improved. As shown in  FIG. 19 , reinforcing ribs  468  for strengthening the main drawer  460  is formed on the bottom surface of the main drawer  460 . The reinforcing ribs  468  are formed to protrude downward from the bottom surface of the main drawer  460  by a predetermined height, wherein the forming direction is determined to be in the fore and aft direction of the main drawer  460 . Furthermore, the reinforcing ribs  468  are preferably formed to be arranged from side to side at equi-intervals. In the storage space of the auxiliary drawer  440  (see  FIGS. 4 to 18 ), lower ends of the reinforcing ribs  468  comes into contact with the inner surface of the auxiliary drawer  440 . 
     FIGS. 20 to 22  are views for explaining a refrigerator double drawer according to a fifth embodiment of the present invention, which has a configuration for mitigating collision between an auxiliary drawer and a main drawer and shock and noise caused therefrom. 
   As shown in  FIGS. 20 to 22 , a refrigerator double drawer  400  of the present embodiment is provided with shock absorbing members  448  at the front ends of the auxiliary drawer  440 . The shock absorbing members  448  mitigate collision between the main drawer  460  and the auxiliary drawer  440  and the shock caused therefrom. 
   In the present embodiment, the shock absorbing members  448  are attached to the front ends of side walls  440   b  of the auxiliary drawer  440 , and thus serve to mitigate the shock when the double drawer  400  is opened and closed and accordingly the main drawer  460  and the auxiliary drawer  440  collide. It is preferred that the shock absorbing member  448  be formed of elastic material such as rubber. 
   In the double drawer  400  of the present embodiment, simultaneously when or successively after the main drawer  460  slides out forward, the auxiliary drawer  440  also slides out forward by means of the guide rails  420 . A state where the main drawer  460  and the auxiliary drawer  440  completely slide out is shown in  FIG. 22 . 
   When the main drawer  460  and the auxiliary drawer  440  slide out forward as described above, the user accommodates foods in an accommodating space  460 ′ of the main drawer  460  or takes out the accommodated food. 
   Next, in order to push the main drawer  460  into the refrigerator, a force is exerted to the front plate  464  rearward. Thus, the main drawer  460  and the auxiliary drawer  440  simultaneously or successively move back and finally become into a state shown in  FIG. 21   
   At this time, the shock absorbing members  448  mitigate the collision between the main drawer  460  and the auxiliary drawer  440  and the shock caused therefrom. That is, when the main drawer  460  moves back rapidly and the main drawer  460  collides against the auxiliary drawer  440 , the shock absorbing members  448  attached to the front ends of the side walls  440   b  of the auxiliary drawer  440  collides against the main drawer  460  thus mitigating the shock. 
   In the present embodiment, the rubber is illustrated as the shock absorbing member  448 . However, other materials serving to mitigate shock may be used as the shock absorbing member  448 . Further, it is described in the foregoing that the shock absorbing members  448  are provided on the front ends of the side walls  440   b  of the auxiliary drawer  440 . However, the installation positions of the shock absorbing members  448  may be diversely changed. That is, the shock absorbing members  448  may be attached to a front end of a bottom wall  440   a  of the auxiliary drawer  440  or to rear sides of the front end of the main drawer  460  (i.e., the portions brought into contact with the front end of the auxiliary drawer). 
   Each of the shock absorbing members  448  is formed as one piece to vertically extend on the front end of each of the side walls  440   b  of the auxiliary drawer  440  as described in the aforementioned embodiment. Alternatively, the shock absorbing member  448  may be provided only on an upper portion of the front end of each side wall  440   b  of the auxiliary drawer  440 , or a plurality of members into which the shock absorbing member  448  is separated are provided on the upper, lower, and middle portions of the front end of each side wall. 
     FIGS. 23 to 25  are views illustrating a refrigerator double drawer according to a sixth embodiment of the present invention. Referring to  FIGS. 23 to 25 , a double drawer  400  according to the present embodiment will be described below. 
   In the present embodiment, sliding members  462 ′ are provided on both side surfaces of the main drawer  460 , respectively. The sliding members  462 ′, which cause the main drawer  460  to slide smoothly, are formed on rear ends of both the side surfaces of the main drawer  460 . 
   The sliding members  462 ′ are formed on the rear ends of both the side surfaces of the main drawer  460 , more particularly, at positions corresponding to opening type drawing rails  450 , which will be described below. The sliding members  462 ′ are also formed to protrude vertically from both the side surfaces of the main drawer  460  by a predetermined distance. 
   The sliding members  462 ′ are formed to have predetermined thickness and width so as to support the weight of the main drawer  460  and foods accommodated therein. The configuration of each sliding member  462 ′ may be diversely modified. In the same manner as the previous embodiment, the main drawer  460  is seated in the auxiliary drawer  440  and slides in and out in the fore and aft direction in the auxiliary drawer  440 . 
   The auxiliary drawer  440  is formed in a box shape as a whole and larger than the main drawer  460  so that the main drawer  460  is seated in auxiliary drawer  440 . In addition, the front face of the auxiliary drawer  440  is fully opened, so that the main drawer  460  seated in the auxiliary drawer  440  is caused to easily slide forward. The upper face of the auxiliary drawer  440  is also opened, thus making it easy to check the inside of the main drawer  460  and the food accommodated therein. 
   The opening type drawing rails  450  are formed in both side walls of the auxiliary drawer  440 . The drawing rails  450 , which guide the slide of the sliding members  462 ′ formed on both side surfaces of the main drawer  460 , are formed in positions corresponding to the sliding members  462 ′ so as to receive the sliding members  462 ′ when the main drawer  460  is seated in the auxiliary drawer  440 . 
   In detail, the drawing rails  450  are formed to extend from the rear ends of both the side walls of the auxiliary drawer  440  at least up to the middle portions thereof and to be bored through both the side walls of the auxiliary drawer  440 . 
   An insertion portion  457  is formed in the rear end of each drawing rail  450 . The insertion portion  457 , which is an insertion passage of the sliding member  462 ′, is formed to be opened upward at the rear end of the drawing rail  450 . 
   Therefore, the main drawer  460  can be securely seated in the auxiliary drawer  440  merely by positioning the sliding members  462 ′ formed on both the side surfaces of the main drawer  460  to the insertion portions  457  of the auxiliary drawer  440  and inserting the main drawer  460  into the opening type drawing rails  450 . 
   The sliding members  462 ′ slide on lower surfaces of the opening type drawing rails  450 . Seating portions  452  are formed in both ends of each of the drawing rails  450 . The seating portions  452 , which function as catching portions against the sliding members  462 ′, are formed to be depressed to be somewhat larger than the sliding members  462 ′ and to have a shape similar to the sliding members  462 ′. 
   The sliding members  462 ′ sliding along the lower surfaces of the drawing rails  450  are seated in the seating portions  452  of both the ends of the drawing rails  450 , and stop sliding. 
   In the meantime, rolling members  442  are provided on both the side surfaces of the auxiliary drawer  440  on which the drawing rails  450  are provided. The rolling members  442  may roll along guide rails  420 , which will be described below, such that the auxiliary drawer  440  can slide or be formed in a protrusion shape similar to the sliding member  462 ′, if desired. 
   The rolling members  442  are mounted on upper rear portions of both the side surfaces of the auxiliary drawer  440 , i.e., above the drawing rails  450 , respectively. In addition, sliding guides  444  are formed to extend from the positions, in which the rolling members  442  are mounted, to the front ends of the auxiliary drawer  440 . 
   The sliding guides  444 , which serve to prevent the auxiliary drawer  440  from sagging downward when the auxiliary drawer  440  slides in and out, are formed to protrude outward with a predetermined width. 
   The auxiliary drawer  440  is mounted to the guide rails  420 . The guide rails  420 , which serve to guide the slide of the auxiliary drawer  440 , are installed on the left and light sides of the refrigerator main body  100  (see  FIG. 3 ), more particularly, on the left and light side surfaces of the upper portion of the drawer chamber  300 . 
   Each of the guide rails  420  is formed in an elongated quadrangular plate shape. A protrusion  424  and a receiving portion  422  are formed on the middle portion of each guide rail  420  to extend along the longitudinal direction of the guide rail  420 . 
   The protrusion  424  is formed along the peripheral portion of the guide rail  420  to protrude inward by a predetermined distance with a predetermined width. Therefore, the receiving portion  422  is naturally formed to be depressed in the inside of the portion in which the protrusion  424  is formed. The configuration of the receiving portion  422  is determined according to the protrusion  424 . 
   The receiving portion  422 , which the rolling member  442  is in contact with and rolls in, is formed with a predetermined width so that the rolling member  442  stably rolls and moves. 
   Hereinafter, the operation of the double drawer  400  of a refrigerator according to the present invention so configured will be described. 
     FIG. 25  is a schematic view showing the operation of the refrigerator double drawer according to the present embodiment. Referring to the figure, in a state where the double drawer  400  is completely accommodated in the refrigerator, the sliding members  462 ′ of the main drawer  460  are seated in the seating portions  452  at the rear ends of the opening type drawing rails  450 , and the rolling members  442  of the auxiliary drawer  440  are positioned at the rear ends of the guide rails  420 . 
   In order to pull the double drawer  400 , when the front plate  464  formed on the front of the main drawer  460  is gripped and pulled forward, the auxiliary drawer  440  first slides out forward. 
   At this time, the main drawer  460  does not slide out before the auxiliary drawer  440 . It is the reason why the sliding members  462 ′ causing the main drawer  460  to slide in and out are seated in the seating portions  452  at the rear ends of the opening type drawing rails  450  and a predetermined force is required to cause the sliding members  462 ′ to go over the seating portions  452  and move. 
   On the other hand, the second rolling members  442  that allows the auxiliary drawer  440  to slide are positioned at the rear ends of the receiving portions  422  of the guide rails  420 . Further, although the rear ends of the receiving portions  422  are somewhat inclined, the second rolling members  442  can go over the inclinations with a force smaller than a force needed for allowing the first rolling members  462 ′ to go over the seating portions  452 . Thus, the auxiliary drawer  440  first slides out. 
   When the front plate  464  is pulled continuously until the auxiliary drawer  440  no more slides out after the auxiliary drawer  440  slides out to a certain extent, a force for pulling the main drawer  460  forward becomes larger than that for causing the sliding members  462 ′ to go over the seating portions  452 . 
   Accordingly, the sliding members  462 ′ go over the seating portions  452  and then slide along the lower ends of the drawing rails  450 . The slide of the sliding members  462 ′ causes the main drawer  460  to be pulled forward from the inside of the auxiliary drawer  440 . 
   Then, when the sliding members  462 ′ are positioned in the seating portions  452  at the front ends of the opening type drawing rails  450 , the main drawer  460  no more slides out and thus the pulling of the main drawer  460  and auxiliary drawer  440  is completed. 
   In the meantime, upon review of the process of sliding in the double drawer  400 , when the front plate  464  of the main drawer  460  is pushed rearward, the seating portions  452  at the front ends of the opening type drawing rails  450  cause the rolling members  442  mounted to the auxiliary drawer  440  to roll and move first in the same manner as the double drawer  400  slides out. 
   When the movement of the rolling members  442  is completed, the sliding members  462 ′ go over the seating portions  452  and move rearward along the opening type drawing rails  450 . Thus, the main drawer  460  slides in rearward. When the main drawer  460  completely slides in, the double drawer  400  is returned to its initial position before it slides out. 
   In addition, in a case where the double drawer  400  is necessary to be disassembled for cleaning or services, by lifting the main drawer  460  up when the main drawer  460  is completely accommodated in the auxiliary drawer  440 , the sliding members  462 ′ escape through the insertion portions  457  of the opening type drawing rails  450  and thus the main drawer  460  is separated from the auxiliary drawer  440 . 
   Then, after completely sliding out along the guide rails  420 , the auxiliary drawer  440  is lifted forward in the inclined direction of about 45 degrees, and thus, the auxiliary drawer  440  can be separated from the guide rails  420  through the opening portions of the protrusions  424 . 
   When disassembling the double drawer, either of the auxiliary drawer  440  and the main drawer  460  can be first disassembled. The assembly process of the double drawer  400  is made in reverse order of the above disassembly process. Even at this time, any one of the auxiliary drawer  440  and the main drawer  460  may first be assembled regardless of the order. 
     FIGS. 26 to 30  are views illustrating a refrigerator double drawer according to a seventh embodiment of the present invention.  FIG. 26  is an exploded perspective view showing the major portions of the refrigerator double drawer;  FIG. 27  is a perspective view showing a bottom of an auxiliary drawer of the refrigerator double drawer; and  FIG. 28  is a side view of the auxiliary drawer. 
   As shown in  FIGS. 27 and 28 , an auxiliary drawer door  471  is mounted to a lower surface of an auxiliary drawer  440  according to the present embodiment. The auxiliary drawer door  471 , which selectively opens and closes an open front face of the auxiliary drawer  440 , is formed with a size to close the open face of the auxiliary drawer  440 . Fixing protrusions  472  are formed to vertically protrude on upper and lower ends of both side surfaces of the auxiliary drawer door  471 , respectively. The fixing protrusions  472  are mounted in door guides  473 , which will be described below, and assist the auxiliary drawer  440  to be mounted, slide and pivot. 
   The door guides  473  are formed to vertically protrude on both side ends of the bottom surface of the auxiliary drawer  440  and to extend from front to rear end of the auxiliary drawer  440  by a height of the auxiliary drawer door  471 . 
   Sliding holes  473 ′ are defined between the bottom surface of the auxiliary drawer  440  and the door guides  473  to extend longitudinally from front to rear ends of the door guides  473  so that the fixing protrusions  472  formed on both the side surfaces of the auxiliary drawer door  471  are mounted and slide in the sliding holes  473 ′. 
   Therefore, when the auxiliary drawer  440  assists the main drawer  460  (see  FIG. 26 ) to be guided with the main drawer  460  being seated in the auxiliary drawer  440 , the auxiliary drawer door  471  is mounted on the bottom surface of the auxiliary drawer  440  in parallel therewith. 
   As shown in  FIGS. 26 to 30 , when the auxiliary drawer  440  is also used as an accommodating space with the main drawer  460  being separated from the auxiliary drawer  440 , the auxiliary drawer door  471  selectively closes the open front face of the auxiliary drawer  440 . 
   Further, in order to fix the auxiliary drawer door  471  to the front face of the auxiliary drawer  440 , fixing grooves  474  are formed in the front ends of both side walls of the auxiliary drawer  440 . The fixing grooves  474  are formed so that the fixing protrusions  472  formed on the upper ends of both the side surfaces of the auxiliary drawer door  471  are inserted into the fixing grooves  474  when the auxiliary drawer door  471  closes the front face of the auxiliary drawer  440 . 
   In the meantime, the same auxiliary drawer  440  as employed in the previous embodiments is mounted to the guide rails  420 . The guide rails  420 , which are installed on the upper left and right side surfaces of the drawer chamber  300  to guide the slide of the auxiliary drawer  440 , respectively, have been already described in the previous embodiments. 
   In the meantime, when the main drawer  460  is separated from the auxiliary drawer  440  and then each of the drawers is practically used as an independent accommodating space, as shown in  FIGS. 29 and 30 , the main drawer  460  is slidably mounted in auxiliary rails  480  of a refrigerator main body. The auxiliary rails  480  guide the slide of the main drawer  460 , to which rolling members  462  are mounted, in the fore and aft direction. 
   Each of the auxiliary rails  480  is formed in an elongated quadrangular plate shape. A rail groove  482  is formed in a side of the auxiliary rail  480  so that each rolling member  462  of the main drawer  460  is inserted into the rail groove  482 . 
   The rail grooves  482  are formed in substantially middle portions of the auxiliary rails  480  to be depressed with a length corresponding to the main drawer  460  so that the main drawer  460  slides in and out sufficiently. Therefore, the rolling members  462  of the main drawer  460  roll in the rail grooves  482 , thus causing the main drawer  460  to slide in and out. 
   The auxiliary rails  480  are formed in the same configuration as the guide rails  420 , so that the auxiliary rails  480  may be mounted at necessary positions in the refrigerator main body  100  and can be formed integrally in the refrigerator main body  100 . 
   The auxiliary rails  480  may be mounted at any positions at which the main drawer  460  can be mounted in the refrigerator main body  100 . In the embodiment of the present invention, the auxiliary rails  480  are mounted on the sides of the guide rails  420 , i.e., in the upper left portion of the drawer chamber  300 . 
   Hereinafter, the operation of the separable double drawer of a refrigerator according to the present invention so configured will be described with reference to the figures. 
   When the main drawer  460  and the auxiliary drawer  440  are separated from each other and used as respective independent accommodating spaces, in a state where the main drawer  460  is fully accommodated in the auxiliary drawer  440 , the rolling members  462  of the main drawer  460  is caused to escape through the insertion portions  457  of the auxiliary drawer  440  by lifting the main drawer  460  upward. 
   After the main drawer  460  is separated from the auxiliary drawer  440  by allowing the rolling members  462  to escape, the main drawer  460  is mounted to the auxiliary rails  480  provided in the upper left portion of the drawer chamber  300 . At this time, by mounting the rolling members  462  of the main drawer  460  to the rail grooves  482  formed in the auxiliary rails  480 , the main drawer  460  can slide in and out in the fore and aft direction. 
   In addition, the auxiliary drawer  440  slides in and out when the auxiliary drawer  440  is mounted to the guide rails  420 , and provides an additional accommodating space. At this time, the auxiliary drawer door  471  mounted to the auxiliary drawer  440  causes the front face of the auxiliary drawer  440  to be closed. 
   When the main drawer  460  is seated in the auxiliary drawer  440  and thus used as the double drawer  400 , the auxiliary drawer door  471  is mounted on the bottom surface of the auxiliary drawer  440  in order not to prevent the main drawer  460  from sliding in and out. 
   When the main drawer  460  is separated from the auxiliary drawer  440 , the auxiliary drawer door  471  slides out of the door guides  473  forward after the separated main drawer  460  is mounted to the auxiliary rails  480 . Then, the auxiliary drawer door  471  pivots upward and the fixing protrusions  472  of the auxiliary drawer door  471  are inserted into and fixed to the fixing grooves  474 . 
   Therefore, the main drawer  460  and the auxiliary drawer  440  define the respective independent accommodating spaces. When the main drawer  460  is seated in the auxiliary drawer  440  again in order to utilize the spaces of the drawer chamber  300 , in reverse order of the above process, after the auxiliary drawer door  471  is mounted on the bottom surface of the auxiliary drawer  440 , the main drawer  460  is seated in the auxiliary drawer  440  to be used. 
   In such an embodiment, when the main drawer  460  is separated from the auxiliary drawer  440  and they are used as the respective independent accommodating spaces, the auxiliary rails  480  to which the main drawer  460  is mounted are provided in the upper left portion of the drawer chamber  300 . However, the auxiliary rails  480  may be provided, if desired, in the drawer chamber  300  or the refrigerating chamber  200 . A plurality of the auxiliary rails  480  may be configured to have the same size, so that they can be used at any positions. 
     FIGS. 31 to 34  are views for illustrating a refrigerator double drawer according to an eighth embodiment of the present invention.  FIG. 31  is an exploded perspective view showing the refrigerator double drawer according to the present embodiment;  FIG. 32  is a perspective view showing an auxiliary drawer that is one of major portions of the present embodiment;  FIG. 33  is a side view showing the main drawer that is one of the major portions of the refrigerator double drawer according to the present embodiment, wherein the main drawer is mounted on upper drawing rails; and  FIG. 34  is a side view showing the main drawer that is one of the major portions of the refrigerator double drawer according to the present embodiment, wherein the main drawer is mounted on lower drawing rails. 
   As shown in  FIGS. 31 and 32 , an auxiliary drawer  440  according to the present embodiment is formed to be in the form of a drawer larger than a main drawer  460  in order for the main drawer  460  to be seated in the auxiliary drawer  440 . The front face of the auxiliary drawer  440  is fully opened, so that the main drawer  460  seated in the auxiliary drawer  440  is caused to easily slide forward. The upper face of the auxiliary drawer  440  is opened, thus making it easy to check the inside of the main drawer  460  and to accommodate foods in the auxiliary drawer  440 . 
   In addition, the auxiliary drawer  440  is formed with a rear upper portion and both rear side walls thereof being opened, thus making it easy to mount the auxiliary drawer  440  to guide rails  420 . Further, both side walls of the auxiliary drawer  440  are formed to vertically extend downward by a predetermined length. 
   Upper drawing rails  450   a  are formed on upper portions of both the side walls of the auxiliary drawer  440 , respectively. The upper drawing rails  450   a , which guide the rolling of first rolling members  462  formed on both side walls of the main drawer  460 , are formed to protrude outward at positions corresponding to the first rolling members  462  when the main drawer  460  is seated in the auxiliary drawer  440  so that the first rolling members  462  are accommodated in the upper drawing rails  450   a . At this time, the sliding members  462 ′ (see  FIG. 23 ) integrally formed on the main drawer may be used instead of the first rolling members  462 . 
   In addition, upper insertion portions  457   a  are formed in the rear ends of the upper drawing rails  450   a . The upper insertion portions  457   a , which are passages for insertion of the first rolling members  462 , are formed to be opened upward at the rear ends of the upper drawing rails  450   a.    
   Therefore, in order to allow the main drawer  460  to be securely seated in the auxiliary drawer  440 , the first rolling members  462  formed on both the side surfaces of the main drawer  460  are positioned in the upper insertion portions  457   a  of the auxiliary drawer  440 . Then, the main drawer  460  is inserted into the upper drawing rails  450   a , so that the main drawer  460  is seated in the auxiliary drawer  440 . 
   In the meantime, lower drawing rails  450   b  are formed on lower portions of both the side walls of the auxiliary drawer  440 , respectively. The lower drawing rails  450   b  are mounted with the main drawer  460  separated from the upper drawing rails  450   a  when the user intends to expand the accommodating space in the refrigerator. The first rolling members  462  provided on both the side surfaces of the main drawer  460  are seated and roll in the lower drawing rails  450   b.    
   The lower drawing rails  450   b  are formed to extend from the front to rear ends of the auxiliary drawer  440 . Lower insertion portions  457   b  are formed at the front ends of the lower drawing rails  450   b . The lower insertion portions  457   b  are formed to be opened at the front ends of both the side walls of the auxiliary drawer  440  so that the first rolling members  462  of the main drawer  460  can be inserted into and escape from the lower insertion portions  457   b.    
   Therefore, in order for the user to mount the main drawer  460  separated from the upper drawing rails  450   a  to the lower drawing rails  450   b , by inserting the first rolling members  462  into the lower insertion portions  457   b  and pushing the main drawer  460  rearward, the first rolling members  462  roll up to the rear ends of the lower drawing rails  450   b  and thus the main drawer  460  slides in the auxiliary drawer  440 . 
   In order to stop the main drawer  460  from sliding out when the main drawer  460  fully slides out of the lower drawing rails  450   b , catching portions  458  for limiting the rolling of the first rolling members  462  are formed on substantially middle portions of the lower drawing rails  450   b , respectively. 
   The catching portions  458  are formed to protrude upward by a predetermined height larger than a radius of the first rolling members  462  so that the first rolling members  462  are caught to the catching portions  458  and thus the rolling of the first rolling members  462  is limited during the rolling of the first rolling members  462 . 
   The portions of the catching portions  458  to which the first rolling members  462  are caught when the main drawer  460  slides out are vertically formed so as to effectively limit the rolling of the first rolling members  462 . The portions of the catching portions  458  which the first rolling members  462  are brought into contact with when the main drawer is mounted are formed slantingly at a predetermined angle so that the first rolling members  462  effectively go over the catching portions  458 . 
   In addition, in order for the main drawer  460  not to escape easily when the main drawer  460 , which is mounted to the lower drawing rails  450   b  and completely accommodated therein, slides out of the lower drawing rails  450   b , a width between the upper and lower portions of each lower drawing rail  450   b  in the range from the rear end of the lower drawing rail  450   b  to the catching portion  458  is somewhat larger than the diameter of the first rolling member  462 . 
   On the other hand, a width between the upper and lower portions of each lower drawing rail  450   b  in the range from the front end of the lower drawing rail  450   b  to the catching portion  458  is larger than the diameter of the first rolling member  462  by the height of the catching portion  458  so that the first rolling members  462  go over the catching portions  458  effectively when the first rolling members  462  are mounted to the lower drawing rails  450   b.    
   In the meantime, second rolling members  442  are provided on both the side surfaces of the auxiliary drawer  440  formed with the upper and lower drawing rails  450   a  and  450   b . The second rolling members  442  which cause the auxiliary drawer  440  to slide along the guide rails  420  to be described below have the same configuration as the first rolling members  462 . 
   Hereinafter, the operation of the aforementioned refrigerator double drawer will be described with reference to  FIGS. 33 and 34 . 
   As shown in the figures, in the double drawer  400 , when the main drawer  460  is used in a state where it is mounted to the upper drawing rails  450   a , the first rolling members  462  of the main drawer  460  are accommodated in the upper drawing rails  450   a  and roll in the upper drawing rails  450   a . The rolling of the first rolling members  462  causes the main drawer  460  to be slid. 
   At this time, in a state where the main drawer  460  is completely accommodated in the auxiliary drawer  440 , the first rolling members  462  are positioned at the rear ends of the upper drawing rails  450   a . When the front plate  464  formed in the front of the main drawer  460  is pulled forward, the first rolling members  462  roll forward along the upper drawing rails  450   a , so that the main drawer  460  slides out forward. 
   At the same time, the second rolling members  442  of the auxiliary drawer  440  roll forward along the guide rails  420 , so that the auxiliary drawer  440  is guided by the guide rails  420  and slides out forward. 
   Therefore, since the protrusion of the auxiliary drawer  440  is added to the protrusion of the main drawer  460 , the main drawer  460  more protrudes to the outside from the inside of the drawer chamber  300  (see  FIG. 3 ), so that foods are taken out through the open upper face of the main drawer  460  that is exposed to the outside. 
   In order to cause the double drawer  400  to slide in, when the front plate  464  of the main drawer  460  is pushed rearward, the first rolling members  462  roll rearward along the upper drawing rails  450   a  and the second rolling members  442  roll rearward along the guide rails  420 . Thus, the main drawer  460  and the auxiliary drawer  440  are completely accommodated rearward. 
   Meanwhile, in order to accommodate foods necessary to be stored in a separate storage space or to be separately stored, by mounting the main drawer  460  to the lower portion of the auxiliary drawer  440 , both of the auxiliary drawer  440  and the main drawer  460  can be practically used as spaces necessary for accommodating foods. 
   In detail, in order to separate the main drawer  460  from the upper drawing rails  450   a , the main drawer  460  is pushed rearward so that the main drawer  460  is completely accommodated and the first rolling members  462  are positioned at the rear ends of the upper drawing rails  450   a.    
   When the first rolling members  462  are positioned at the rear of the upper drawing rails  450   a , the main drawer  460  is caused to be lifted up. At this time, the first rolling members  462  escape out through the upper insertion portions  457   a  formed at the rear ends of the upper drawing rails  450   a , so that the main drawer  460  is separated from the auxiliary drawer  440 . 
   Next, after moving the separated main drawer  460  to the lower front of the auxiliary drawer  440 , the first rolling members  462  of the main drawer  460  are inserted into the lower insertion portions  457   b  formed to be opened at the front ends of both the side walls of the auxiliary drawer  440 . 
   By pushing the main drawer  460  rearward after inserting the first rolling members  462  into the lower insertion portions  457   b  to be mounted to the lower drawing rails  450   b , the first rolling members  462  roll rearward smoothly, go over the catching portions  458  formed in the lower drawing rails  450   b  and then are positioned at the rear ends of the lower drawing rails  450   b , so that the main drawer  460  is completely mounted to the lower drawing rails  450   b.    
   When the main drawer  460  is mounted to the lower drawing rails  450   b  as described above, the upper portion of the auxiliary drawer  440  is used as an accommodating space, i.e., an independent tray, while the main drawer  460  provides an additional accommodating space to the lower portion of the auxiliary drawer  440 . 
   In the meantime, if the front plate  464  is gripped and pulled out in order to cause the main drawer  460  to slide out when the main drawer  460  is mounted to the lower drawing rails  450   b , the first rolling members  462  roll forward in the lower drawing rails  450   b  and thus cause the main drawer  460  to slide out forward. 
   Further, the first rolling members  462  roll and move up to the catching portions  458  in the lower drawing rails  450   b . When the catching portions  458  and the first rolling members  462  are brought into contact with each other, the rolling of the first rolling members  462  is limited by the catching portions  458 , so that the main drawer  460  is stopped from sliding out. 
   At the same time, the second rolling members  442  of the auxiliary drawer  440  roll forward in the receiving portions  422  of the guide rails  420 , so that the auxiliary drawer  440  slides out forward. 
   The forward slide of the auxiliary drawer  440  causes the main drawer  460  to more protrude outward. Thus, the portion of the auxiliary drawer  440 , which functions as a tray, is exposed to the outside. Further, the main drawer  460  slides out along the lower drawing rails  450   b  and is exposed to the outside. Thus, the user is enabled to accommodate foods in the tray of the auxiliary drawer  440  and the main drawer  460 . 
   In order to cause the double drawer  400  to slide in, by pushing the front plate  464  rearward, the double drawer slides in the reverse order of the foregoing. 
   In the meantime, in order to separate the main drawer  460  from the lower drawing rails  450   b  and mount the main drawer  460  to the upper drawing rails  450   a  again, when the main drawer  460  slides out forward and then the first rolling members  462  are positioned to the catching portions  458 , the main drawer  460  is caused to slide out forward after it is lifted at a predetermined height. 
   When the main drawer  460  slides out continuously after going over the catching portions  458 , the first rolling members  462  escape to the outside through the lower insertion portions  457   b  in the front of the lower drawing rails  450   b , so that the main drawer  460  is separated from the auxiliary drawer  440 . 
   Next, after moving the main drawer  460  to the upper portion of the auxiliary drawer  440 , the first rolling members  462  are inserted into the upper insertion portions  457   a  formed in the rear ends of the upper drawing rails  450   a . When the first rolling members  462  are inserted into the upper insertion portions  457   a , the first rolling members  462  are positioned at the rear ends of the upper drawing rails  450   a , so that the main drawer  460  is seated in the auxiliary drawer  440 . 
     FIGS. 35 to 37  are views for illustrating a refrigerator double drawer according to a ninth embodiment of the present invention.  FIG. 35  is an exploded perspective view showing the refrigerator double drawer according to the present embodiment;  FIG. 36  is a perspective view showing an auxiliary drawer as a major portion of the present embodiment; and  FIG. 37  is a schematic view illustrating the operation of the refrigerator double drawer according to the present embodiment. 
   As shown in  FIGS. 35 to 37 , a front face of an auxiliary drawer  440  of the present embodiment is completely opened, which makes it easy to cause a main drawer  460  seated in the auxiliary drawer  440  to slide out forward, while an upper face of an auxiliary drawer  440  is opened, which makes it more easy to check the inside of the main drawer  460  and to accommodate food therein. 
   In addition, a partition  445  for partitioning the auxiliary drawer  440  into front and rear sections is provided in the auxiliary drawer  440 . The partition  445  vertically protrudes on a floor surface of the auxiliary drawer  440  upward by about a height of the auxiliary drawer  440 . 
   The length from the front end of the floor surface of the auxiliary drawer  440  to the partition  445  is not longer than the length between the front and rear ends on a floor surface of the main drawer  460 . Therefore, when the main drawer  460  slides in rearward after being seated in the auxiliary drawer  440 , the rear surface of the main drawer  460  is brought into contact with the partition  445 . 
   At this time, the partition  445  is formed with the height such that all of cold air inlets  466  formed in the rear wall of the main drawer  460  are not closed in order for the cold air to be introduced into the main drawer  460  smoothly. 
   The length from the rear end of the floor surface of the auxiliary drawer  440  to the partition  445  may be determined arbitrary according to use. The partition  445  causes an additional storage space S to be formed in the rear of the partition  445  in the auxiliary drawer  440 , so that the food necessary to be separated can be stored. 
   In the meantime, drawing rails  450  are formed on both side walls of the auxiliary drawer  440 . The drawing rails  450 , which guide the rolling of first rolling members  462  provided on both side surfaces of the main drawer  460 , are formed to extend from the front ends of both the side walls of the auxiliary drawer  440  to positions at which the partition  445  is formed. 
   Insertion portions  457  which are passages for insertion of the first rolling members  462 , are defined at the front ends of the drawing rails  450 . Each of the insertion openings  457  is defined to be opened at the front of the auxiliary drawer  440  and to have a diameter somewhat larger than that of the first rolling member  462  in order for the first rolling member  462  to be easily inserted therein. 
   Catching portions  458  are formed in the drawing rails  450 , respectively. The catching portions  458 , which limit the additional sliding motion of the main drawer  460  when the main drawer  460  completely slides out, are formed to protrude upward by a predetermined height. 
   In the meantime, second rolling members  442  are provided on both side surfaces of the auxiliary drawer  440  to which the drawing rails  450  are mounted. The second rolling members  442 , which cause the auxiliary drawer  440  to slide along guide rails  420  to be described below, have the same configuration as the first rolling members  462 . 
   The second rolling members  442  are installed on upper portion, i.e., above the drawing rails  450 , at rear portions of both the side surfaces of the auxiliary drawer  440 . Sliding guides  444  are formed from positions at which the second rolling members  442  are provided to the front ends of the auxiliary drawer  440 . 
   The sliding guides  444 , which cause the auxiliary drawer  440  not to sag when the auxiliary drawer  440  slides in and out, are formed to protrude outward with a predetermined width. 
   The auxiliary drawer  440  is mounted to the guide rails  420 . The guide rails  420 , which guide the slide of the auxiliary drawer  440 , are installed on the left and right sides of the refrigerator main body  100 , particularly, on the upper left and right side surfaces of the drawer chamber  300  (see  FIG. 3 ), respectively. 
   A protrusion  424  and a receiving portion  422 , which extend in the longitudinal direction of each guide rail  420 , are formed on the middle portion of each guide rail  420  which is formed in a rectangular plate shape. 
   The protrusion  424  is formed along the peripheral portion of the guide rail  420  to protrude inward by a predetermined distance with a predetermined width. Therefore, the receiving portion  422  is naturally defined to be depressed in the inside of the portion in which the protrusion  424  is formed. The shape of the receiving portion  422  is determined according to the shape of the protrusion  424 . 
   The receiving portion  422 , which the second rolling member  442  is in contact with and rolls in, is formed with a predetermined width so that the second rolling member  442  can stably rolls and moves. 
   Hereinafter, the operation of the refrigerator double drawer so configured will be described with reference to  FIG. 37 . 
   When a user causes the main drawer  460  to slide out forward completely, the auxiliary drawer  440  also slides out forward. The additional storage space S defined by the partition  445  in the rear portion of the auxiliary drawer  440  is also exposed to the outside, so that the food necessary to be separated can be stored in the additional storage space S. 
   In order to cause the double drawer  400  to slide in after foods are accommodated in or taken out of the main drawer  460  or the additional storage space S in the auxiliary drawer  440  defined by the partition  445 , by gripping the front plate  464  and pushing it rearward, the first rolling members  462  roll in the drawing rails  450  rearward. 
   When the first rolling members  462  roll up to the rear ends of the drawing rails  450 , the rear surface of the main drawer  460  is brought into contact with the partition  445 . When the user pushes it rearward continuously, the second rolling members  442  mounted to the auxiliary drawer  440  roll along the guide rails  420  and thus cause the auxiliary drawer  440  to slide in. 
   Therefore, the main drawer  460  and the auxiliary drawer  440  are completely accommodated in the drawer chamber  300 , and the additional storage space S in the auxiliary drawer  440  defined by the partition  445  is also accommodated in the drawer chamber  300 . 
   As described above, the present invention provides the refrigerator double drawer, which comprises a main drawer, an auxiliary drawer having drawing rails which assist the main drawer to slide out, and guide rails assisting the auxiliary drawer to slide out. Thus, there are advantages in that an extended length of the main drawer can be increased, and the durability can also be improved since the main drawer can withstand a moment resulting from the weight of the foods accommodated in the main drawer by the extended length in spite of the increase in the extended length. 
   In addition, the present invention causes the parts of the double drawer to be easily disassembled, and thus there is an advantage in that the cleaning and management of the double drawer can be easily performed. Further, according to the present invention, the reinforcing ribs formed on the main drawer causes the strength of the main drawer to be considerably increased. The present invention has also an advantage in that the noise and the damage of the double drawer caused from the collision between the main drawer and the auxiliary drawer can be prevented. 
   Further, according to the present invention, since the main drawer can be detachably mounted in the auxiliary drawer and the main drawer can be selectively mounted to the upper and lower drawing rails of the auxiliary drawer, there is an advantage in that the space efficiency in a refrigerator main body is considerably increased. 
   Furthermore, since the present invention has the configuration so that the main drawer and the auxiliary drawer can slide in and out successively, there is also an advantage in that it is possible for a user to use the double drawer conveniently. 
   The present invention has been described based on the specific embodiments. However, it will be apparent that those skilled in the art can make various modifications, alterations and changes within the scope of the invention defined by the claims. Therefore, the aforementioned descriptions and the accompanying drawings should be construed not as limiting the technical spirit of the present invention but as illustrating the present invention.