Patent Publication Number: US-2010123377-A1

Title: Cabinet

Description:
RELATED APPLICATIONS 
     This application claims priority to China Application Serial Number 200810181059.X, filed Nov. 20, 2008, which is herein incorporated by reference. 
     BACKGROUND 
     1. Field of Invention 
     The present invention relates to a cabinet for electronic devices. More particularly, the present invention relates to a cable protecting and storing module. 
     2. Description of Related Art 
     A cabinet for large server may contain a lot of electronic devices like hard discs, video disc players, processors, and fans. The cabinet may have connectors disposed thereon to electrically connect the electronic devices and a power supply to electrically connect the electronic devices and a print circuit board. 
     The connectors in the cabinet are often designed to be hot swappable or hot pluggable, which means the ability to remove electronic devices from the server without rebooting while it is operating. The cabinet is usually designed to have a large chassis with many drawers to contain electronic devices, and connectors disposed on the drawers to connect the electronic devices and a circuit board fixed in the chassis. When the drawers are pulled out of the chassis, the connectors and the circuit board may be disconnected, and therefore power supplying and data communication of the electronic devices may stop. 
     However, sometimes the drawer is pulled out of the chassis to check if the electronic device is well functioned, instead of to replace the electronic device. Disconnecting the electronic device repeatedly during operating may interact the operating server, stop calculation, and furthermore damage the server and the electronic device. 
     To solve the above problem, a cable may be added to connect the connector and the circuit board. Since the cable is flexible, it may bend or stretch when the drawer is pushed In or pulled out of the chassis, and the connection between the connector and the circuit board may not be cut off. 
     The cable must be long enough to allow the entire drawer pulled out of the chassis, which may cause problems to store the cable. Specifically, when the drawer is pushed into the chassis, the cable may be bent to interpose between the drawer and the chassis to stop the drawer moving, or may press the electronic devices or electronic components of the server nearby, or may be winded around. 
     Therefore, a new cable protecting module and a cabinet thereof to limit the route of the cable when it stretches or bends is needed. 
     SUMMARY 
     A cabinet to limit the rouge of the cable when the cable is bending and stretching is provided. The cabinet has a chassis, a drawer a cable chain, and a spring. The chassis has an inner surface, and the drawer is slidably connected with the chassis. 
     The cable chain comprises a plurality of chain monomers. Each immediately-adjacent two chain monomers are pivotally concatenated. The cable chain is bendable within the same plane. One end of the cable chain is connected the inner surface of the chassis and the cable chain bends back to connect the drawer with the other end thereof. 
     The spring is fastened on the inner surface and contacts a pad of the cable chain to push the pair of the cable chain toward the inner surface. Therefore, the spring may push the part of the cable chain to move toward or against the inner surface. 
     Additionally, this invention provides another cabinet. The cabinet has a chassis, a drawer, a cable chain, and a spring. The chassis has an inner surface, and the drawer is slidably connected with the chassis. 
     The cable chain has a plurality of clockwise chain monomers concatenated to form at least a clockwise section, and a plurality of counter-clockwise chain monomers concatenated to form at least a counter-clockwise section and at least a lengthening section, wherein an included angle between each two immediately-connected clockwise chain monomers consists of a range of 0 degree to 180 degrees, and an included angle between each two immediately-connected counter-clockwise chain monomers consists of a range of 180 degrees to 360 degrees. 
     The lengthening section is connected the inner surface of the chassis and bent back to be series connected to the clockwise section. The counter-clockwise section is connected the drawer and series connected to the clockwise section. 
     The clockwise section, the counter-clockwise section and the lengthening section are bendable within the same plane. When the drawer slides forward to the chassis along the slide, the clockwise section and the counter-clockwise section are bent back and forth between the chassis and the drawer. 
     The spring is fastened on the inner surface and contacts a part of the lengthening section to push the part of the lengthening section toward the inner surface of the chassis. In one embodiment of this invention, the spring pushes the part of the lengthening section against the inner surface. 
     This invention also provides another cabinet to contain electronic devices and cables. The cabinet has a chassis with an inner surface, a drawer slidably connected with the chassis, a cable chain connecting the chassis and the drawer, and a spring fastened on the inner surface of the chassis. 
     The cable chain has clockwise chain monomers and counter-clockwise chain monomers. The clockwise chain monomers are concatenated to form clockwise sections, wherein an included angle between each two immediately-connected clockwise chain monomers is limited in a range of 0 degree to 180 degrees. The counter-clockwise chain monomers are concatenated to form counter-clockwise sections and at least a lengthening section, wherein an included angle between each two immediately-connected counter-clockwise chain monomers is limited in a range of 180 degrees to 360 degrees. 
     The lengthening section is connected the inner surface of the chassis and bent back to be series connected to one of the clockwise sections. The clockwise sections and the counter-clockwise sections are alternatively arranged and connected in a series. Either one of the clockwise sections or one of the counter-clockwise sections is connected the drawer. The clockwise sections, the counter-clockwise sections and the lengthening section are bendable within the same plane. When the drawer slides forward to the chassis along the slide, the clockwise sections and the counter-clockwise sections are bent back and forth between the chassis and the drawer. 
     The spring fastened on the inner surface contacts a part of the lengthening section to push the pad of the lengthening section toward the inner surface of the chassis. In an embodiment of this invention, the spring pushes the part of the lengthening section against the inner surface of the chassis. 
     It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawings as follows: 
         FIG. 1A  is a three-dimensional view of a cabinet according to one embodiment of this invention; 
         FIG. 1B  is a three-dimensional view of the cabinet shown in  FIG. 1A ; 
         FIG. 2  is a three-dimensional view of a cable chain according to another embodiment of this invention; 
         FIG. 3A  is a three-dimensional view of a cable chain according to another embodiment of this invention. 
         FIG. 3B  is a three-dimensional view of a clockwise section of the cable chain shown in  FIG. 3A ; 
         FIG. 3C  is a side view of the clockwise section shown in  FIG. 3B ; 
         FIG. 3D  is a three-dimensional view of a counter-clockwise section of the cable chain shown in  FIG. 3A ; and 
         FIG. 3E  is a side view of the counter-clockwise section shown in  FIG. 3D . 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
     Please refer to  FIG. 1A .  FIG. 1A  is a three-dimensional view of a cabinet  100  according to another embodiment of this invention. The cabinet  100  has a chassis  110  and a drawer  120 . The drawer  120  is sidably connected with the chassis  110 . In the embodiment of this invention, the drawer  120  is connected to the chassis  110  via the slide  112 . 
     The slide  112  may be disposed on the chassis  110  or the drawer  120  or other element of the cabinet  110 . Specifically, the slide  112  is fastened on an inner surface of the chassis  110 . The slide  112  connects an outside surface of the drawer  120 . Therefore, the drawer  120  may slide forward or backward to the chassis  110  along the slide  112 . The drawer  120  may be pushed to be stored inside the chassis  110 , and may be pulled out of the chassis  110 . Please notice that the types and shapes of the slide  112  are many. Although slide  112  is demonstrated in this specification as an example, it does not limit the scope of this invention. 
     The drawer  120  has a space therein to contain at least an electronic device  10 . Some connectors (not shown) may be disposed in the drawer  120  to connect the electronic device  10  and electronic components of the server like a circuit board or power supply. In the embodiment of this invention, the connectors may connect the electronic device  10  and at least a cable  12 , and the cable  12  may connect to the electronic components of the server out of the drawer  120 . 
     Please refer to  FIG. 1A  and  FIG. 2  at the same time.  FIG. 2  is a three-dimensional view of a cable chain  130  according to another embodiment of this invention. The cabinet  100  further Includes a cable chain  130  having a continuous tube  102  to contain the cable  12 , which may secure the cable  12  from hitting the chassis  110 , the drawer  120  elements and/or electronic devices disposed nearby. 
     In the embodiment of this invention, the cable chain  130  comprises many chain monomers  150  series connected each other. Each immediately-adjacent two chain monomers  150  are pivotally concatenated. The chain monomer  150  may rotate around the connected chain monomer  150 , and therefore the cable chain  130  may bend or turn. 
     In the embodiment of this invention, the cable chain  130  is bendable within the same plane. Therefore, each chain monomer  150  may rotate around the connected chain monomer  150  in a plane. 
     The cable chain  130  has two ends. One end of the cable chain  130  is fastened on an inner surface  114  of the chassis  110 . The cable chain  130  bends back to connect the drawer  120  with the other end thereof. In other words, the cable chain  130  makes at least a U-turn, which may be located on the same side of the two ends of the cable chain  130 . 
     The spring  140  is fastened on the inner surface  114  of the chassis  110  near where the end of the cable chain  130  fastened. The spring  140  contacts a part of the cable chain  130  to push the part of the cable chain  130  toward the inner surface  114 . Therefore, the part of the cable chain  130  may be pushed by the spring  140  to move toward the inner surface  114  or may be pushed against the inner surface  114 . 
     In the embodiment of this invention, the spring  140  is a torsional spring, which may has two arms  142  and  144  connecting a twisted portion  146 . When a distance (or an inner angle) between the two arms  142  and  144  is changed, the twisted portion  146  may be twisted, which may generate a spring force. 
     In the embodiment of this invention, the arms  142  and  144  are separated contacted the cable chain  130  and the chassis  110 . Specifically, the twisted portion  146  is fastened on the inner surface  114  of the chassis  110 , the arm  144  is contacted the inner surface  144 , and the arm  142  is contacted a part of the cable chain  130 . 
     Please refer to FIG  1 A,  FIG. 1B  and  FIG. 2  at the same time.  FIG. 1A  shows that the drawer  120  is located inside the chassis  110 .  FIG. 1B  shows that the drawer  120  is pulled out of the chassis  110 . 
     The drawer  120  may move along the slide  112 . Therefore, the drawer  120  may be pulled out of the chassis  110  along the slide  112 , or may be pushed backward into the chassis  110  along the slide  112 . 
     When the drawer  120  is pushed out of the chassis  110 , the drawer  120  may bring the end of the cable chain  130  fastened thereon to move. Since the other end of the cable chain  130  is fastened on the chassis  110 , the entire cable chain  130  may not moves but stretch instead. Each chain monomers  150  of the cable chain  130  may be rotated to change the shape of the cable chain  130 , and furthermore to stretch the cable chain  130  as shown in  FIG. 1B . 
     When the cable chain  130  is stretching, the part of the cable chain  130  contacted the arm  142  of the spring  140  may be pulled away from the inner surface  114 . The distance (or the included angle) between the arms  142  and  144  may be changed, and therefore, a spring force may be generated and transferred to the cable chain  130  via the arm  142 . A direction of the spring force is toward the inner surface  114  of the chassis  110 . 
     On the contrary, when the drawer  120  is pushed back to the chassis  110  along the slide  112 , the drawer  120  may bring the end of the cable chain  130  fastened thereon to move. Since the other end of the cable chain  130  is fastened on the chassis  110 , the cable chain  130  may bend as shown in  FIG. 1A . 
     When the cable chain  130  is bending, the part of the cable chain  130  contacted the arm  142  of the spring  140  may be pushed to move toward the inner surface  114  due to the spring force, and rest of the cable chain  130  may be pulled by the part of the cable chain  130  contacted the arm  142 . Therefore, the spring  140  may help limit the route of the cable chain  130  during stretching and bending. 
     The amount of the spring force is proportional to the amount of the twisted portion  146  is twisted which is proportional to the distance (or the included angle) between two arms  142  and  144 . In the embodiment of this invention, when the arm  142  pushes the part of the cable chain  130  against the inner surface  114  of the chassis  110 , the spring force may be smaller. When the cable chain  130  and the arm  142  have been pulled away from surface  114  as shown in  FIG. 1B , the spring  140  may generate a larger spring force. In the embodiment of this invention, the spring force is from about 0 Newton to about 4 Newtons. 
     As the above, the cable chain  130  comprises many series connected chain monomers  150 . Therefore, the maximum of the spring force may be limited in order not to break the connection of the chain monomers  150 . Specifically, the chain monomers  150  may rotate to stretch the cable chain  130  when the drawer  120  and the cable chain  130  are pulled out of the chassis  110 . The part of the cable chain  130  contacted the arm  142 , which may be one of the chain monomer  150 , may be pulled away from the inner surface  114  by other chain monomers  150  series connected thereof and may be pushed toward the inner surface  114  by the arm  142  of the spring  140  at the same time. If the spring force is too large at that moment, the connection between two immediately-connected chain monomers  150 , wherein one of them is contacted the arm  142 , may be broken. In the embodiment of this invention, the maximum of the spring force is from about 3 Newtons to about 4 Newtons. In a preferable embodiment, the maximum of the spring force is from about 3 Newtons to about 3.5 Newtons. 
     Please refer to  FIG. 1A  and  FIG. 2 . The cable chain  130  may be formed by many series connected chain monomers  150 . 
     In the embodiment of this invention, each chain monomer  150  has a through hole  152  penetrated thereof to allow at least a cable  12  passing through. The chain monomer  150  further has a joining hole  154  and a joining axis  156  separately disposed on two openings of the through hole  152 . One chain monomer  150  may use the joining hole  154  thereof to pivot on the joining axis  156  of another chain monomer  150 , and therefore those two chain monomers  150  may be series connected. 
     Please notice that the types and shapes of the cable chain  130  and the chain monomers  150  thereof are many, and the connection may change as well. Although a type of chain monomers  150  is demonstrated in this specification as an example, it does not limit the scope of this invention. 
     The chain monomer  150  may connect another chain monomer  150  via its own joining axis  156  and may rotate around the joining axis  156  in a range of angles. Due to different designs, the range of angles may be different, which will be described below. 
     Additionally, when the chain monomers  150  are concatenated, the through holes  152  of every chain monomers  150  may join each other to form a continuous tube  132 . The continuous tube  102  may be used to contain at least a wire like a cable  12 . 
     In the embodiment of this invention, the cable  12  may be disposed inside the continuous tube  102  of the cable chain  130 . An end of the cable  12  may extend out of the end of cable chain  130  fastened on the chassis  110  to connect the electronic components of the server. The other end of the cable  12  may extend out of the end of cable chain  130  fastened on the drawer  120  to connect the electronic device  10 . In another embodiment of this invention, the cable  12  may connect the electronic device  10  through connectors (not shown) disposed on the drawer  120 . 
     In the embodiment of this invention, the chain monomer  150  may rotate around the connected chain monomer  150  clockwise and counter-clockwise. In another embodiments of this invention, the chain monomer  150  may only rotate around the connected chain monomer  150  clockwise or counter-clockwise. 
     Please refer to  FIG. 3A ,  FIG. 3B , and  FIG. 3C .  FIG. 3A  is a three-dimensional view of a cable chain  130  according to another embodiment of this invention.  FIG. 38  is a three-dimensional view of a clockwise section  180  of the cable chain  130  shown in  FIG. 3A .  FIG. 3C  is a side view of the clockwise section  180  shown in  FIG. 3B . 
     In the embodiment of this invention, the cable chain  130  includes many clockwise chain monomers  160  concatenated to form clockwise sections  180 . Each clockwise chain monomer  160  may use the joining hole  154  thereof to pivot on the joining axis  156  of another clockwise chain monomer  160 . The clockwise chain monomer  160  may rotate around the joining axis  156  clockwise, which means the clockwise chain monomer  160  may rotate around the connected clockwise chain monomer  160  clockwise. 
     A first included angle al between each two immediately-connected clockwise chain monomers  160  is limited in a range of 0 degree to 180 degrees, wherein the first included angle a 1  is a vectorial angle. Specifically the clockwise chain monomer  160   a  may use the joining axis  156  thereof to connect the joining hole  154  of the clockwise chain monomer  160   b.  The angle between the clockwise chain monomer  160   a  and the clockwise chain monomer  160   b  is the first included angle a 1 . The clockwise chain monomer  160   a  may rotate around the clockwise chain monomer  160   b  clockwise (as the first direction  200 ) or counter-clockwise (as the second direction  210 ) as long as the first included angle al is limited from about 0 degree to about 180 degrees. 
     The range of the first included angle a 1  may change as well as the design of the clockwise chain monomers  160  are changed. For example, the first included angle a 1  may be limited in a range of about 120 degrees to about 180 degrees. In the embodiment of this invention, the first included angle a 1  is limited in about 90 degrees to about 180 degrees. Therefore, only two situations may happen. In one situation, the two connected clockwise chain monomers  160  may line up, which means the first included angle a 1  is about equal to 180 degrees. In the other, the clockwise chain monomer  160  may rotate clockwise around the connected clockwise chain monomer  160 , which is connected via joining axis  156  thereof. In other words, the clockwise section  180  may only bend clockwise, not counter-clockwise. 
     Each clockwise chain monomer  160  has stoppers disposed thereof to stop the clockwise section  180  from bending counter-clockwise. Many different kinds of structure may be used to complete the above limitation. Stoppers described are used as an example and should not limit the scope of this invention. 
     In the embodiment of this invention, a first stopper  162  and a second stopper  164  are disposed separately on two opposite openings of the through hole  152 . The second stopper  164  is fastened on the clockwise chain monomer  160  and may move with the clockwise chain monomer  160  when rotating. The first stopper  162  is a block located in a path of the second stopper  164  of the connected clockwise chain monomer  160  when the second stopper  164  moves counter-clockwise with the connected clockwise chain monomer  160 . In the embodiment, when the first included angle a 1  is about equal to 180 degrees the first stopper  162  may touch the second stopper  164  to stop the second stopper  164  from moving forward. 
     Additionally, when the clockwise chain monomers  160  are concatenated, the through holes  152  of every clockwise chain monomers  160  may join each other to form a continuous tube  132 . 
     Please refer to  FIG. 3A ,  FIG. 3D , and  FIG. 3E  at the same time.  FIG. 3D  is a three-dimensional view of a counter-clockwise section  182  of the cable chain  130  shown in  FIG. 3A .  FIG. 3E  is a side view of the counter-clockwise section  182  shown in  FIG. 3D . 
     In the embodiment of this invention, the cable chain  130  includes many counter-clockwise chain monomers  170  concatenated to form counter-clockwise sections  182 . Please notice that the types and shapes of the counter-clockwise chain monomer  170  are many, and the connection of the counter-clockwise chain monomers  170  may change as well. Although some counter-clockwise chain monomers  170  are demonstrated in this specification as an example, it does not limit the scope of this invention. In the embodiment of this invention, each counter-clockwise chain monomer  170  has a joining hole  154  and a joining axis  156 . One counter-clockwise chain monomer  170  may use the joining hole  154  thereof to pivot on the joining axis  156  of another counter-clockwise chain monomer  170 , and therefore those two counter-clockwise chain monomers  170  may be series connected. 
     A second included angle a 2  between each two immediately-connected counter-clockwise chain monomers  170  is limited in a range of 180 degrees to 360 degrees, wherein the second included angle a 2  is a vectorial angle. Specifically, the counter-clockwise chain monomers  170   a  may rotate around the counter-clockwise chain monomers  170   b  clockwise or counter-clockwise (as the second direction  210 ) as long as the second included angle a 2  is limited from about 180 degree to about 360 degrees. 
     The range of the second included angle a 2  may change as well as the design of the counter-clockwise chain monomers  170  are changed. For example, the second included angle a 2  may be limited from about 180 degrees to about 300 degrees. In the embodiment of this invention, the second included angle a 2  is from about 180 degrees to about 270 degrees. Therefore, only two situations may happen. In one situation, the two counter-clockwise chain monomers  170  may line up, which means the second included angle a 2  is equal to about 180 degrees. In the other, the counter-clockwise section  182  may only bend counter-clockwise, not clockwise. 
     To stop the counter-clockwise section  182  from bending clockwise, the counter-clockwise chain monomer  170  has stoppers disposed thereof. In the embodiment of this invention, a first stopper  162  and a second stopper  164  are disposed separately on two opposite openings of a through hole  152  of the counter-clockwise chain monomer  170 . The second stopper  164  is fastened on the counter-clockwise chain monomer  170  and may move with the counter-clockwise chain monomer  170  when rotating. The first stopper  162  is a block located in a path of the second stopper  164  of the connected counter-clockwise chain monomer  170  when the second stopper  164  moves clockwise. In the embodiment, when the second included angle a 2  is about equal to 180 degrees, the first stopper  162  may touch the second stopper  164  and stop the second stopper  164  from moving forward. Please notice that stoppers described are used as an example, and should not limit the scope of this invention. In fact, many different kinds of structures may be used to complete the above limitation. 
     Additionally, when the counter-clockwise chain monomers  170  are concatenated, the through holes  152  of every counter-clockwise chain monomer  170  may join each other to form a continuous tube  132 . 
     Please refer to  FIG. 1A  and  FIG. 3A  at the same time. The cable chain  130  shown in  FIG. 3A  has a plurality of clockwise sections  180  and a plurality of counter-clockwise sections  182  alternatively arranged and connected in a series. The clockwise sections  180  and the counter-clockwise sections  182  are bendable within the same plane. Because the clockwise sections  180  may only bend clockwise and the counter-clockwise sections  182  may only bend counter-clockwise, the cable chain  130  may bend back and forth like a letter W. 
     The cable chain  130  further includes a lengthening section  184  to lengthen the cable chain  130 , which may provide designers more possibility of the location of circuit board (not shown) or other connectors. The lengthening section  184  has a plurality of concatenated monomers. Each monomer of the lengthening section  184  may rotate around the connected monomer clockwise and/or counter-clockwise. The clockwise sections  180 , the counter-clockwise sections  182  and the lengthening section  184  are bendable within the same plane. Please notice that the types and shapes of the monomer are many, and the connection of the monomers may change as well. The monomers of the lengthening section  184  may be chain monomers  150  as shown in  FIG. 2 , clockwise chain monomers  160  as shown in  FIG. 3B  and  FIG. 3C , or counter-clockwise chain monomers  170  as shown in  FIG. 3D  and  FIG. 3E . In the embodiment of this invention, the monomers of the lengthening section  184  are counter-clockwise chain monomers  170 . 
     Additionally, since the clockwise sections  180 , the counter-clockwise sections  182 , and the lengthening section  184  are series connected, the through holes  152  thereof may join to form the continuous tube  152  to contain at least a cable  12 . 
     In the embodiment of this invention, an end of the lengthening section  184  is connected the inner surface  114  of the chassis  110  and the other end thereof is series connected to one of the clockwise sections  180 . The clockwise sections  180  are alternatively arranged and series connected to the counter-clockwise sections  182 . 
     Therefore, the lengthening section  184  is located at an end of the cable chain  130 , and the other end of the cable chain  130  is either one of the clockwise sections  180  or one of the counter-clockwise sections  182 , which is depend on the length of the cable chain  130  and the needs of the designer. In the embodiment of this invention, the last section of the cable chain  130  is one of the counter-clockwise sections  182 , which is fastened on the drawer  120 . 
     As described above, the included angle between the connected clockwise chain monomers  160  is limited. It may take at least  3  clockwise chain monomers  160  to make a U turn. Accordingly, the number of the clockwise chain monomers  160  of each clockwise section  180  may not be less than 3. Similarly, the number of the counter-clockwise chain monomers  170  of each counter-clockwise section  106  may not be less than 3. Furthermore, the number of the monomers of the lengthening section  184  may be larger than the sum of a number of the clockwise chain monomers  160  of one clockwise section  180  and a number of the counter-clockwise chain monomers  130  of one counter-clockwise section  106 . The number of the chain monomers  110  of the lengthening section  184  may not less than 6. 
     However, when too many clockwise chain monomers  160  are connected in one clockwise section  120 , the clockwise section  120  may bend to form a circuit, which may press other sections. Therefore, the number of the clockwise chain monomers  160 , as well as the number of the counter-clockwise chain monomers  130 , may be limited. In the embodiment, the number of the clockwise chain monomers  160  of each clockwise section  180  may not be more than 6. Similarly, the number of the counter-clockwise chain monomers  130  of each counter-clockwise section  106  may not be more than 6. 
     In the foregoing, the cabinet  100  and the cable chain  130  this invention disclosed may protect the cable  12  from being damaged during pulling or pushing the drawer  120 . The rouge of the cable  12  may be limited by the cable chain  130  and the spring  140  during stretching and/or bending. 
     The spring  140  contacts part of the cable chain  130  to push it toward the inner surface  114  of the chassis  110 , which may help the cable chain  130  to bend between the chassis  110  and the drawer  120 . Therefore, the cable  12  may no longer press the electronic components nearby or interpose between the drawer  120  and the chassis  110  to stop the drawer  120  moving. 
     Although the present invention has been described in considerable detail with reference certain embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims.