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CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the priority benefit of Korean Patent Application No. 10-2011-0130420, filed on Dec. 7, 2011 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     The following description relates to a refrigerator configured to adjust the height of a body independent of the height of a door thereof, and prevent the deflection of a door thereof even when used for a long term period. 
     2. Description of the Related Art 
     In general, a refrigerator is an apparatus provided with a storage compartment therein to store foods and a cooling device to supply cool air to the storage compartment to keep food fresh. The storage compartment is provided in a form of having an open front side, and the open front side is open/closed by a door rotatively installed on the body of the refrigerator. 
     The door as such is rotatively coupled to the body by an upper portion hinge and a lower portion hinge of the refrigerator. However, the door may not be disposed at a precise height due to an error during an assembly process or an error during a manufacturing process. In the case as such, an operational malfunction of the door as well as a hindrance to aesthetic beauty of the refrigerator may develop. 
     Thus, a refrigerator configured to adjust the height of a door thereof is under development. An example of the refrigerator as such has been suggested in Korean patent publication No. 10-2008-0094778 and in Korean patent publication No. 10-2008-0050137. 
     According to the publications above, the door of a refrigerator is supported by a hinge bracket which is fixed to the body of the refrigerator, and a door rotation shaft is coupled to the hinge bracket so as to enable ascending/descending, so that the relative height of the door with respect to the body of the refrigerator may be adjusted by raising/lowering the door rotation shaft. 
     However, with reference to the refrigerator as such, in a case when the height of the body of the refrigerator with respect to the bottom surface is changed, the height of the door thereof is also needed to be changed with respect to the bottom surface. In addition, the weight of the door is applied to the hinge bracket, and thereby a deflection of the hinge bracket may occur. 
     SUMMARY 
     Therefore, it is an aspect of the present disclosure to provide a refrigerator configured to independently adjust the height of a body and a door thereof. 
     It is another aspect of the present disclosure to provide a lower portion hinge structure of a refrigerator capable of preventing the deformation such as a deflection even when used for a long term period. 
     Additional aspects of the disclosure will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the disclosure. 
     In accordance with one aspect of the present disclosure, a refrigerator includes a body, a storage compartment, a door, and a lower portion hinge. The storage compartment may be provided at an inside the body. The door may be provided at a front of the body to open/close a front surface of the storage compartment. The lower portion hinge may be installed at a lower portion of the body to rotatively support the door. The lower portion hinge may include a fixed bracket, a mobile bracket. The fixed bracket may have one portion thereof fixedly coupled to a bottom surface of the body while the other portion thereof protruded toward a front side of the body. Left/right and forward/backward movements except for up/down movements of the mobile bracket may be restrained by the fixed bracket, and the mobile bracket may include a door cam for the door to be placed thereon and a door rotation shaft that is inserted into a lower portion of the door. A body supporting leg configured to support a weight of the body may be screwed to a lower portion of the fixed bracket, and a door supporting leg configured to support a weight of the door may be screwed to a lower portion of the mobile bracket. A height of the body may be adjusted by rotating the body supporting leg, and a height of the door may be adjusted by rotating the door supporting leg, so that the height of the body is adjusted independent of the height of the door. 
     A vertical bracket protruded toward a lower side may be formed at the mobile bracket, and a vertical bracket accommodating portion into which the vertical bracket is inserted may be formed at the fixed bracket, so that left/right and forward/backward movements except for up/down movements of the mobile bracket may be restrained by the fixed bracket. 
     The vertical bracket and the mobile bracket are formed as an integral body. 
     The vertical bracket accommodating portion may be formed in a way that a width of left/right directions thereof is wider than a width of forward/backward directions thereof. 
     At least one guide protrusion may be formed at an upper side of the vertical bracket accommodating portion to guide the movement of the vertical bracket. 
     A first male screw portion may be formed at one of the fixed bracket and the body supporting leg, and a first female screw portion at which the first male screw portion is coupled may be formed at the remaining one of the fixed bracket and the body supporting leg. 
     A second male screw portion may be formed at one of the mobile bracket and the door supporting leg, and a second female screw portion at which the second male screw portion is coupled may be formed at the remaining one of the mobile bracket and the door supporting leg. 
     A door supporting shaft may be formed as the second male screw portion and the second female screw portion are coupled to each other by a screw, and the door supporting shaft may not be provided in collinear with the door rotation shaft. 
     The door supporting shaft may be provided at the inner side of the body when compared to the door rotation shaft. 
     A tool coupling portion may be provided on at least one of the body supporting leg and the door supporting leg so that a tool is coupled to the tool coupling portion to rotate the at least one of the body supporting leg and the door supporting leg. 
     The tool coupling portion may be provided in a form of a groove vertically elongated. 
     In accordance with another aspect of the present disclosure, a refrigerator a body, a storage compartment, a door and a lower portion hinge. The storage compartment may be provided at an inside the body. The door may be provided at a front of the body to open/close a front surface of the storage compartment. The lower portion hinge may be installed at a lower portion of the body to rotatively support the door. The lower portion hinge may include a fixed bracket and a mobile bracket. The fixed bracket may have one portion thereof fixedly coupled to a bottom surface of the body while the other portion thereof protruded toward a front side of the body. Left/right and forward/backward movements except for up/down movements of the mobile bracket may be restrained by the fixed bracket, and the mobile bracket may include a door cam for the door to be placed thereon and a door rotation shaft that is inserted into a lower portion of the door. The fixed bracket may be provided with a first leg coupling portion to which a body supporting leg configured to support a weight of the body is screwed so as to enable ascending/descending. The mobile bracket may be provided with a second leg coupling portion to which a door supporting leg configured to support a weight of the door is screwed so as to enable ascending/descending. 
     Each of the first leg coupling portion and the second leg coupling portion may be one of a male screw portion and a female screw portion. 
     In accordance with another aspect of the present disclosure, a refrigerator includes a body, a storage compartment, a door, a fixed bracket, a mobile bracket, a body supporting leg, and a door supporting leg. A storage compartment may be provided at an inside the body. The door may be provided at a front of the body to open/close a front surface of the storage compartment. The fixed bracket may have a base portion disposed at a bottom surface of the body so as to be fixed to the bottom surface of the body, and a front protrusion portion protruded from the base portion to a front side of the body. The front protrusion portion may have a vertical bracket accommodating portion formed thereon to restrain a movement of the door. The mobile bracket may be disposed at an upper side of the front protrusion portion of the fixed bracket while having a door cam at which the door is placed, a horizontal bracket provided with a door rotation shaft inserted into a lower portion of the door, and a vertical bracket vertically inserted in a sliding manner into the vertical bracket accommodating portion. The body supporting leg may be coupled to a lower portion of the fixed bracket by a screw to support a weight of the body and adjust a height of the body. The door supporting leg may be coupled to a lower portion of the mobile bracket by a screw to support a weight of the door and adjust a height of the door. 
     The door rotation shaft may be formed as an integral body with the horizontal bracket, and may be protruded toward an upper side of the horizontal bracket. 
     The door cam may be formed as a separate body from the horizontal bracket, and may be screwed and fixed to an upper side of the horizontal bracket. 
     The vertical bracket may be formed as an integral body with the horizontal bracket, and may be bent toward a lower side of the horizontal bracket. 
     As described above, the height of the door of a refrigerator and the height of the body of a refrigerator may be independently adjusted. 
     In addition, since each of the door and the body of a refrigerator is supported at the floor surface through a separate leg, the deflection of a hinge bracket may be prevented. 
     In addition, a tool coupling portion is formed at the outer circumferential surface of a door supporting leg, thereby able to easily rotate the door supporting leg. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects of the disclosure will become apparent and more readily appreciated from the following description of embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG. 1  is a drawing illustrating an exterior of a refrigerator in a state that the door of the refrigerator is open in accordance with an embodiment of the present disclosure. 
         FIG. 2  is a perspective view illustrating a body separated from a door of the refrigerator of  FIG. 1 . 
         FIG. 3  is an exploded perspective view of a lower portion hinge of the refrigerator of FIG. 
         FIG. 4  is an assembled perspective view of a lower portion hinge of the refrigerator of  FIG. 1 . 
         FIG. 5  is a side view of a lower portion hinge of the refrigerator of  FIG. 1 . 
         FIG. 6  is a plane view of a door supporting leg of the refrigerator of  FIG. 1 . 
         FIG. 7  is a drawing to explain the operation of ascending/descending a door supporting leg of the refrigerator of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. 
       FIG. 1  is a drawing illustrating an exterior of a refrigerator in a state that the door of the refrigerator is open in accordance with an embodiment of the present disclosure.  FIG. 2  is a perspective view illustrating a body separated from a door of the refrigerator of  FIG. 1 . 
     Referring to  FIGS. 1 to 2 , a refrigerator  1  according to an embodiment of the present disclosure includes a body  10 , storage compartments  11  and  12  provided at the inside the body  10 , doors  20  and  30  coupled to the body  10  to open/close the open front sides of the storage compartments  11  and  12 , and a cooling apparatus (not shown) configured to supply cool air to the storage compartments  11  and  12 . 
     The body  10  includes an inner case  3  to form the storage compartments  11  and  12 , an outer case  4  to form an exterior while being coupled to an outer side of the inner case  3 , and an insulation material (not shown) foamed between the inner case  3  and the outer case  4  to insulate the inside the storage compartments  11  and  12 . 
     The storage compartments  11  and  12  may be used as a refrigerating compartment where foods are stored as refrigerated while the temperature therein is maintained between 0° C. to 5° C., or as a freezing compartment where foods are stored as frozen while the temperature therein is maintained at about −20° C. The storage compartments  11  and  12  are divided between each other by a middle portion  7 . 
     The storage compartments  11  and  12  may be provided with a shelf  8  for the foods to be placed thereon, and the inside space of the storage compartments  11  and  12  may be divided into an upper space and a lower space by the shelf  8 . In addition, the storage compartments  11  and  12  may be provided therein with an ice making apparatus  5  to make ice. The cooling apparatus may include a compressor, a condenser, an expansion apparatus, an evaporator, a draft fan, and a cooling duct. The vapor coolant that is compressed at high pressure and high temperature through the compressor is liquefied through the condenser, and the liquefied coolant passes through the expansion apparatus and changes to the low-temperature and low-pressure state that may easily be evaporated. The coolant is evaporated while going through the evaporator, the surrounding heat may be taken away. 
     The doors  20  and  30  are rotatively coupled to the body  10  and may open the open front surface of the storage compartments  11  and  12 . A left door  20  may open/close a left storage compartment  11 , and a right door  30  may open/close a right storage compartment  12 . The left storage compartment  11  and the right storage compartment  12  may be different to each other in size, and accordingly, the left door  20  and the right door  30  may also be different to each other in size. 
     The doors  20  and  30  may be provided therein with a dispenser  6  through which water or ice may be taken out from the outside the refrigerator  1  without having to open the doors  20  and  30 . 
     The doors  20  and  30  as such may be rotatively coupled to the body  10  by upper portion hinges  150  and  250  and lower portion hinges  100  and  200 . A rotation shaft insertion groove  21  may be formed at the upper portion of the left door  20  so that a door rotation shaft  151  of the upper portion hinge  150  on the left side may be inserted into the rotation shaft insertion groove  21 , and a rotation shaft insertion groove  22  may be formed at the lower portion of the left door  20  so that a door rotation shaft  122  of the lower portion hinge  100  on the left side may be inserted into the rotation shaft insertion groove  22 . 
     Similarly, a rotation shaft insertion groove  31  may be formed at the upper portion of the right door  30  so that a door rotation shaft  251  of the upper portion hinge  250  on the right side may be inserted into the rotation shaft insertion groove  31 , and a rotation shaft insertion groove  32  may be formed at the lower portion of the right door  30  so that a door rotation shaft  222  of the lower portion hinge  200  on the right side may be inserted into the rotation shaft insertion groove  32 . 
     Therefore, the left door  20  may be rotated while having the door rotation shaft  151  and the door rotation shaft  122 , which are formed by the upper portion hinge  150  on the left side and the lower portion hinge  100  on the left side, as a center of rotation, and the right door  30  may be rotated while having the door rotation shaft  251  and the door rotation shaft  222 , which are formed by the upper portion hinge  250  on the right side and the lower portion hinge  200  on the right side, as a center of rotation. 
     The lower portion hinges  100  and  200  as such provide the axes for the doors  20  and  30  to rotate thereon, and configured to support the weight of the door  20  and the door  30  at the floor surface. 
     Meanwhile, as illustrated on  FIG. 2 , the lower portion hinges  100  and  200  of the refrigerator  1  according to an embodiment of the present disclosure may include fixed brackets  110  and  210  that are fixed to the bottom surface of the body  10  and mobile brackets  120  and  220  that are coupled to the fixed brackets  110  and  210  in a way that the mobile brackets  120  and  220  may ascend/descend. 
     In addition, body supporting legs  130  and  230  are coupled to the fixed brackets  110  and  210 , and door supporting legs  140  and  240  that are separately provided from the body supporting legs  130  and  230  and may be coupled to the mobile brackets  120  and  220 . 
     Therefore, the weight of the body  10  is supported at the floor surface through the body supporting legs  130  and  230 , and the weight of the door  20  and the door  30  may be supported at the floor surface by the door supporting legs  140  and  240  separately from the body  10 . 
     The structure of the lower portion hinges  100  and  200  as such will hereafter be explained in detail. 
       FIG. 3  is an exploded perspective view of a lower portion hinge of the refrigerator of  FIG. 1 .  FIG. 4  is an assembled perspective view of a lower portion hinge of the refrigerator of  FIG. 1 .  FIG. 5  is a side view of a lower portion hinge of the refrigerator of  FIG. 1 .  FIG. 6  is a plane view of a door supporting leg of the refrigerator of  FIG. 1 .  FIG. 7  is a drawing to explain the operation of ascending/descending a door supporting leg of the refrigerator of  FIG. 1 . 
     Hereafter, since the structure of the lower portion hinge  200  on the right side is identical to the structure of the lower portion hinge  100  on the left side, the structure of the lower portion hinge  100  on the left side will only be explained while the explanation on the structure of the lower portion hinge  200  on the right will be omitted. 
     By referring to the  FIGS. 1 to 7 , the lower portion hinge may include the fixed bracket  110  and the mobile bracket  120 . 
     The fixed bracket  110  is provided while having a shape of an approximately elongated flat panel. One portion of the fixed bracket  110  is fixedly coupled to the bottom surface of the body  10 , while the other remaining portion may be protruded toward the front of the body  10 . Hereafter, the portion which is fixed to the bottom portion of the body  10  is referred to as a base portion  111  ( FIG. 5 ), and the other remaining portion which is protruded toward the front from the base portion  111  is referred to as a front protrusion portion  114 . 
     The base portion  111  may be firmly coupled to the bottom surface of the body  10  through a fastening screw  112 , and at this time, a reinforcing panel  40  to reinforce the fastening strength may be coupled to the upper side of the bottom surface of the body  10 . 
     A first male screw portion  113  having a screw thread on the outer circumferential surface thereof may be formed at the bottom portion of the base portion  111  of the fixed bracket  110  so that the body supporting leg  130  may be coupled by use of a screw to the bottom portion of the base portion  111  of the fixed bracket  110 . A first female screw portion  131  having a screw thread on the inner circumferential surface thereof may be formed at the body supporting leg  130  so that the first female screw portion  131  may be coupled by use of a screw to the first male screw portion  131 . 
     Although not illustrated, a female screw portion may be formed at the base portion  111 , and a male screw portion may be formed at the body supporting leg  130 . However, it is desired that the male screw portion or the female screw portion is provided with a sufficient length thereof to adjust the height of the base portion  111  of the fixed bracket  110  by tightening the screw or loosening the screw. 
     Here, since the base portion  111  of the fixed bracket  110  is fixed to the bottom surface of the body  10 , the changing of the height of the base portion  111  of the fixed bracket  110  refers to the changing of the height of the body  10 . 
     However, in order to adjust the height of the body  10  while maintaining the body  10  at level, the body supporting leg  230  on the right side and supporting legs on the rear left/right sides of the body  10  as well as the body supporting leg  130  on the left side are needed to be adjusted. Thus, the adjusting of the height of one of the lower portion hinges  100  and  200  of the door may be considered to adjusting the level state of the body  10 . 
     The front protrusion portion  114  is a portion which is protruded toward the front of the body  10  for the door  20  to be supported. The front protrusion portion  114  is provided with a vertical bracket accommodating portion  115  formed therein, and the vertical bracket accommodating portion  115  is configured that a vertical bracket  126  may be inserted thereinto. The vertical bracket accommodating portion  115  will be explained later. 
     The fixed bracket  110  may be formed with various material, and as an example, the fixed bracket  110  may be manufactured through a die casting of the zinc material. 
     The mobile bracket  120  may support the door  20  as the door  20  is placed thereon, and is configured to be ascended or descended. The mobile bracket  120  may include a horizontal bracket  121  provided in a horizontal direction and a vertical bracket  126  extended from one end of the horizontal bracket  121  toward a lower side. The horizontal bracket  121  and the vertical bracket  126  may be integrally formed with each other, and may be provided with metallic material. 
     The horizontal bracket  121  is provided thereon with the door rotation shaft  122  that is inserted into the rotation shaft insertion groove  22  of the door  20  and is configured to form the rotation axis for the door  20 . The door rotation shaft  122  is protruded toward the upper side of the horizontal bracket  121 , and may be integrally formed with the horizontal bracket  121 . 
     In addition, the horizontal bracket  121  is provided thereon with a door cam  123  configured to support the door  20  while the door  20  is effectively adhered thereto, and formed in a cam shape for the door  20  to be automatically open/closed. The door cam  123  may be provided with a separate compartment from the mobile bracket  120 , and may be coupled to the upper surface of the horizontal bracket  121  by a fastening member  124 . 
     In addition, the horizontal bracket  121  is provided thereon with a second female screw portion  125  having a screw thread at the inner circumferential surface thereof for the door supporting leg  140 , which supports the weight of the door  20  at the floor surface, to be coupled to the horizontal bracket  121  by a screw. In response to such, a second male screw portion  141 , which is inserted into and screwed to the second female screw portion  125 , may be formed at the door supporting leg  140 . 
     Although not illustrated, a male screw portion may be formed at the horizontal bracket  121 , and a female screw portion may be formed at the door supporting leg  140 . However, similar to the case of the fixed bracket  110  and the body supporting leg  130  which is previously explained, it is desired that the male screw portion or the female screw portion is provided with a sufficient length thereof to adjust the height of the mobile bracket  120  by tightening the screw or loosening the screw. 
     The second male screw portion  141  and the second female screw portion  125  may be coupled to each other and form a door supporting shaft to support a door. Here, the door supporting shafts are provided in collinear with the door rotation shaft  122 . 
     That is, as illustrated on  FIG. 4 , the door supporting shafts, in order to support further the weight of the door  20  in a stable manner, may be formed at a nearer position to the inner side of the body  10  when compared to the door rotation shaft  122 . 
     The vertical bracket  126  may be inserted into the vertical bracket accommodating portion  115  of the fixed bracket  110 , which is previously explained, in a way that the vertical bracket  126  may be ascended or descended. That is, the vertical bracket  126  may be able to slide upward/downward at the vertical bracket accommodating portion  115 . However, since the vertical bracket  126  and the vertical bracket accommodating portion  115  are provided with the shapes corresponding to each other, the vertical bracket  126  inserted into the vertical bracket accommodating portion  115  may only be able to move toward upward/downward directions in a sliding manner while not being able to move back/forth and left/right directions at the inside the vertical bracket accommodating portion  115 . 
     Thus, the vertical bracket accommodating portion  115  is configured to restraint the back/forth and left/right direction movements of the vertical bracket  126  other than the upward/downward. More specifically, the mobile bracket  120  may only be able to move toward upward/downward directions with respect to the fixed bracket  110 , not toward forward/backward or left/right directions. Furthermore, the door  20  which is supported by the mobile bracket  120  may only be able to move toward upward/downward directions, not toward forward/backward or left/right directions, with respect to the body  10 . 
     In particular, by considering that the door  20  is applied with greater amount of strength to forward/backward directions while the door  20  is being open/closed, the vertical bracket accommodating portion  115  is desired to have a wider left-to-right width than a forward-to-backward width so that the forward/backward direction movements of the vertical bracket  126  may be stably restrained. 
     The shape of the vertical bracket  126  is not limited thereto where the vertical bracket  126  extends from one end of the horizontal bracket  121  to the lower side. The vertical bracket  126  may also be provided in a protrusion shape while simply protruded from one portion of the horizontal bracket  121  toward a bottom side. The vertical bracket  126  as such may be integrally formed with the horizontal bracket  121 . 
     The vertical bracket accommodating portion  115  may be provided at the upper side thereof with at least one guide protrusion  116  to guide the vertical bracket  126  while the vertical bracket  126  is being inserted into the vertical bracket accommodating portion  115 . 
     The guide protrusion  116 , after the vertical bracket  126  is inserted into the vertical bracket accommodating portion  115 , may support the vertical bracket  126  so that the mobile bracket  120  may further be restrained in a stable manner. 
     A tool coupling portion  142 , which is configured for tools such as a flat head screw driver  300  to be coupled to, may be provided at the outer circumferential surface of the door supporting leg  140  for the door supporting leg  140  may be easily rotated. 
     The tool coupling portion  142  may be formed at the outer circumferential surface of the door supporting leg  140  in a form of a groove in upward/downward directions. The tool coupling portion  142  may be provided in at least one thereof along the circumferential direction of the door supporting leg  140 , and as an example, as illustrated on  FIG. 6 , the total of four of the tool coupling portions  142  may be provided at an angle of 90° degrees. 
     Thus, as illustrated on  FIG. 7 , the door supporting leg  140  is rotated in a certain angle by coupling a tool at one of the tool coupling portions  142 . Further, the door supporting leg  140  may be rotated manually by a user. After the door supporting leg  140  is rotated in a certain angle, a tool is coupled to the next adjacent tool coupling portion  142  to rotate the door supporting leg  140  again. By the method of rotating the door supporting leg  140  one after another, the door supporting leg  140  which is positioned close to the floor surface may be easily rotated. 
     Although not illustrated, the tool coupling portion  142  as such may also be provided at the body supporting leg  130 , not only at the door supporting leg  140 . 
     Meanwhile, as illustrated on  FIG. 5 , the refrigerator  1  according to the present disclosure may include a moving wheel  50 , apart from the body supporting leg  130  and the door supporting leg  140 , to move the refrigerator  1 , and the moving wheel  50  may be coupled to the bottom portion of the fixed bracket  110 . 
     The operation in adjusting the height of the door and the body of the refrigerator having the structure as such according to an embodiment of the present disclosure will be briefly explained. 
     As illustrated on  FIG. 4 , by rotating the body supporting leg  130 , the height and the level of the body may be adjusted. At this time, since the mobile bracket  120  is irrelevant to the upward/downward movements of the fixed bracket  110  unless the mobile bracket  120  is descended to the position at which the mobile bracket  120  is closely adhered to the fixed bracket  110 , the height of the door, is not changed even if the height of the body is adjusted. 
     In addition, by rotating the door supporting leg  140 , the height of the door may be adjusted. At this time as well, since the fixed bracket  110  is irrelevant to the upward/downward movements of the mobile bracket  120 , the height of the body remains unchanged even the height of the door is adjusted. 
     When the door supporting leg  140  is rotated, a tool such as a flat head screw driver  300  is coupled to the tool coupling portion  142  formed at the outer circumferential surface of the door supporting leg  140  to easily rotate the door supporting leg  140 . 
     Although a few embodiments of the present disclosure have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the disclosure, the scope of which is defined in the claims and their equivalents.

Summary:
A refrigerator capable of adjusting the height of a body independent of the height of a door, in which a lower portion hinge connecting the body to the door includes a fixed bracket having one portion fixed to a bottom surface of the body while having the remaining portion protruded to a front side of the refrigerator, a mobile bracket coupled to the fixed bracket so as to enable a sliding movement and allowing the door to placed thereon, in which a body supporting leg and a door supporting leg are screwed to a lower portion of the fixed bracket and a lower portion of the mobile bracket, respectively, to adjust the respective heights of the fixed bracket and the mobile bracket.