Patent Publication Number: US-2003234329-A1

Title: Attachment mechanism for network device

Description:
BACKGROUND OF THE INVENTION  
       [0001] The present invention relates generally to attachment mechanisms for attaching one or more network devices, such as a hub, a router, and a switch, to an object, such as a desk, a counter, a partition, and a wall.  
       [0002] Along with recent spread of LANs and WANs, many network devices, such as personal computers (“PCs” hereinafter) and hubs, switches, and routers (hubs etc. are also called “agents”) come to get connected to a network and its subnets for information sharing and frequent communications.  
       [0003] Installations of the network devices have recently been diversified according to users&#39; usage modes and installment environments. Specifically, the conventional network device has been a generally horizontal type that is placed horizontally on a table, requiring the large installation space. Therefore, effective use of the installation location has been demanded.  
       [0004] On the other hand, a general-purpose rack, attached to a wall, etc., for accommodating small articles cannot be used as an attachment mechanism for the network device because many cables are connected to the network device for connection with communication apparatuses and thus the general-purpose rack would litter and short-circuit the cables. In particular, when the cable is an optical fiber cable, it would easily get damaged unless it has certain curvature or larger.  
       BRIEF SUMMARY OF THE INVENTION  
       [0005] Accordingly, it is an exemplified object of the present invention to provide an attachment mechanism for a network device, which effectively utilizes a space in which the network device is installed and bundles cables for use with the network device.  
       [0006] In order to achieve the above object, an attachment mechanism of one aspect of the present invention for attaching a network device to an object at a certain angle with respect to a horizontal direction, the network device being connectible to a cable connected to a communication apparatus, and the network device assisting a communication on a network by the communication apparatus includes a support part for supporting a housing of the network device, an accommodation part for accommodating the cable, and an engagement part connectible to the object. The attachment mechanism attaches the network device, for example, at 90 degree with respect to an approximately horizontal top plate of an object, such as a desk, thereby maximizing or effectively utilizing any space under the top plate. The accommodation part accommodates the cable and prevents the cable from littering around the object. In this case, the engagement part may have, for example, an approximately C shape, engaged with an edge of the top plate, for arranging the support part inside the top plate.  
       [0007] The housing may have a first surface and a second surface smaller than the first surface, and wherein the support part supports the network device through the second surface, the housing including a plurality of longitudinally extending terminals connectible to a plurality of communication apparatuses while the housing is supported on the support part. The present invention is especially useful for maximizing the installation space of the vertical network device. There may be provided a bundler member for bundling the cable, wherein the accommodation part includes a connection part, engaged with the bundler member, for bundling the cable on the accommodation part. For example, the bundler member is a tie or tie-wrap. The bundler member may fix the cable and maintain a certain radius of curvature of the cable if needed.  
       [0008] The attachment mechanism may further include a drawer mechanism, movable relative to the support part, for loading the network device onto and ejecting the network device from the support part. Thereby, even when the engagement part is provided at the back of the object, the drawer mechanism facilitates installation and exchange of the network device. There may be provided a drawer mechanism for changing an area of the support mechanism so as to change the number of network devices to be supported. Thereby, the desired number of network devices may be mounted on the support part. The drawer part may have a grip or handle to facilitate a movement of the drawer mechanism.  
       [0009] The attachment mechanism may accommodate a plurality of network devices, and further include a drawer mechanism, movable relative to the support part, for loading and ejecting the plurality of network device independent of the support part. Thereby, a desired network device may be attached and replaced without affecting another network device and a communication apparatus connected to it. There may be provided another engagement part removably attached to another attachment mechanism in order to accommodate a plurality of network devices. Thus, each attachment part may accommodate at least one network device, and be connected to another attachment mechanism. In this case, the engagement part of the other attachment mechanism is not necessary because the other attachment mechanism is not directly connected to the object.  
       [0010] A relative angle between the support part and the engagement part may be configured to be variable. The angle may be set two-dimensionally or three-dimensionally. An adjustment of the relative angle between the support part and the engagement part according to the installation space would facilitate effective use of the installation space. The support part may include a radiator part for radiating heat from the network device. According to this attachment mechanism, the support part serves as a heat radiator, and thus contributes to miniaturization. The support part may include a magnet to hold the network device. If the support part uses screws, a type and manufacturer of the network device to be mounted may possibly be limited, for example, to those having screw holes at predetermined positions. A magnet would easily support an arbitrary shape of network device, and facilitate universal use of the attachment mechanism.  
       [0011] The support part may include a first attachment part for attaching the housing in a first orientation, and a second attachment part for attaching the housing in a second orientation different from the first orientation. Thereby, diversified installations are available according to users&#39; preferences and wiring conditions. The attachment mechanism may be formed by bending one sheet of plate. Thereby, the attachment may be manufactured by an easy method.  
       [0012] The support part may be movable relative to the engagement part. Thereby, even when the engagement part is provided at the back of the object, the drawer mechanism facilitates installation and exchange of the network device. The drawer part may have a grip or handle to facilitate movements of the drawer mechanism. Alternatively, the support part may be movable relative to the object. Thereby, even when the management part is provided at the back of the object, the drawer mechanism facilitates installation and exchange of the network device. A relative angle between the object and the engagement part may be configured to be variable. The angle may be set two-dimensionally or three-dimensionally. An adjustment of the relative angle between the object and the engagement part according to the installation space would facilitate its effective use.  
       [0013] Other objects and further features of the present invention will become readily apparent from the following description of preferred embodiments with reference to accompanying drawings. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0014]FIG. 1 is a schematic perspective view of an attachment instrument of one embodiment according to the present invention, which attaches a network device to a desk.  
     [0015]FIG. 2A is a front view of the attachment instrument shown in FIG. 1, and FIG. 2B is a side view of the attachment instrument shown in FIG. 1.  
     [0016]FIG. 3 is a partial perspective view of ties or tie-wraps engaged with cutouts in the attachment instrument shown in FIG. 1.  
     [0017]FIG. 4 is a schematic perspective view indicating a relationship between the network device shown in FIG. 1 and a fitting.  
     [0018]FIG. 5 is a sectional view taken along a line A-A in FIG. 4.  
     [0019]FIG. 6 is a perspective view of an external appearance of the network device to which the fitting shown in FIG. 4 is attached.  
     [0020]FIG. 7 is a sectional view taken along a line B-B in FIG. 6.  
     [0021]FIG. 8 is a sectional view of a magnet shown in FIG. 4.  
     [0022]FIG. 9 is a perspective view of an external appearance of the network device to which the fitting and magnets shown in FIG. 4 are attached.  
     [0023]FIG. 10 is a sectional view taken along a line C-C in FIG. 9.  
     [0024]FIG. 11 is a schematic perspective view of a drawer mechanism of another embodiment according to the present invention.  
     [0025]FIG. 12 is a schematic sectional view as a variation of the attachment instrument shown in FIG. 2.  
     [0026]FIG. 13 is a schematic sectional view as a variation of the drawer mechanism shown in FIG. 11.  
     [0027]FIG. 14A is a schematic sectional view of another variation of the attachment instrument shown in FIG. 2, and FIG. 14B is a plane view taken along a line F-F in FIG. 14A.  
     [0028]FIG. 15A is a schematic plane view of still another variation of the attachment instrument shown in FIG. 2, and FIG. 15B is its schematic top view.  
     [0029]FIG. 16 is a schematic sectional view of still another variation of the attachment instrument shown in FIG. 2.  
     [0030]FIG. 17 is a schematic sectional view of still another variation of the attachment instrument shown in FIG. 2. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0031] A description will now be given of an attachment instrument  200  of one embodiment according to the present invention with reference to accompanying drawings. Here, FIG. 1 is a schematic perspective view of the attachment instrument  200  that attaches a network device  100  to a desk  1 .  
     [0032] The network device  100  is connectible to one or more cables  130  connected to one or more communication apparatuses, such as a personal computer (not shown), and assists communications on the network by the communication apparatus. The network device  100  broadly covers, for example, a hub, a switch, a router, any other concentrator, a repeater, a bridge, a gateway device, a PC, and a wireless interconnecting device (e.g., an access point as a interconnecting device for wireless LAN).  
     [0033] The network device  100  of this embodiment is configured, for example, as a stackable hub. The stackable hub utilizes, unlike a cascade (or multistage) connection, a plurality of hubs as one hub by connecting them using a dedicated interface. The Ethernet has a cascade rule that only “four stages of 10M hubs” or “two stages of 100M hubs” may be utilized, and an additional network device would require the increased number of ports. The stackable hub is suitable in connecting hubs beyond this limitation.  
     [0034] As shown in FIGS.  1 - 4 , the network device  100  has an approximately rectangular parallelepiped housing  101  including a front surface  102 , a rear surface  104 , a bottom surface  106  and a left side surface  108 . Here, FIG. 4 is a schematic perspective view indicating a relationship between the network device  100  and a fitting  280 .  
     [0035] As shown in FIG. 1, the network device  100  has stack ports  112  and  114  a switch  116 , and LEDs  118  and  120  on the front surface  102 . The stack ports  112  and  114  are used for stack connections, and each connectible to the cable  130  for connection with another hub. The switch  116  is an activation switch of the body. The LED  118  indicates a network state, while the LED  120  indicates a state of a hub itself.  
     [0036] As shown in FIG. 4, the network device  100  includes a 100BASE-TX port  122 , an MDI/MDI-X switch  124 , and a power-supply cable  126  on the rear surface  104 . There are eight longitudinally extending 100BASE-TX ports  122  in this embodiment, each of which are connectible to a UTP connected to an external device, such as a hub of the Ethernet. The 100BASE-TX port  122  automatically recognizes the communication mode (Full Duplex/Half Duplex), and selects the same communication mode as that of the device to be connected. The MDI/MDI-X switch  124  is a switch to determine whether the 100BASE-TX port  212  is used as a cascade connection port or as a normal MDI-X port.  
     [0037] The bottom surface  106  of the housing  101  has the smallest area among surfaces of the housing  101 , and is supported by a horizontal part  214  of a support part  200  of the attachment instrument  200 , which will be described later. As the bottom surface  106  having the smallest installation area in the network device  100  may be easily accommodated in a space  4  under a top plate  2  of the desk  1 , the present invention is especially useful for effective use of the installation space for the vertical network device  100 .  
     [0038] As shown in FIG. 4, the network device  100  includes four pairs of attachment parts  132  to  138  on the left side surface  108 . Each pair of attachment part  132  to  138  has the same interval and size. The attachment parts  132  and  138  are parallel to each other, while the attachment parts  134  and  136  are parallel to each other, and orthogonal to the attachment parts  132  and  138 . The present invention does not limit the number of attachment parts to two. Each of the attachment parts  132  to  138  has, as discussed later, a projection  140  and inlet  142 .  
     [0039] When the network device  100  is a media converter, the cable  130  is an optical fiber cable. The media converter coverts a signal between different media, such as a UTP and an optical cable. The media converter includes, for example, a 100BASE-TX port, a link test switch, a LED for confirming a configuration, a communication mode switch, an MDI/MDI-X switch, a 100BASE-FX port, a DC jack, etc. When the cable  130  is an optical fiber cable, it easily gets damaged without keeping a certain curvature.  
     [0040] A description will now be given of the attachment instrument  200  of one embodiment according to the present invention with reference to FIGS.  1 - 3 . Here, FIG.  2 A is a front view of the attachment instrument  200 , and FIG. 2B is a left side view of the attachment instrument  200 . FIG. 3 is a partial perspective view of ties or tie-wraps engaged with cutouts in the attachment instrument  200 .  
     [0041] The attachment instrument  200  is fixed, as shown in FIG. 1, onto a side  2   a  of the top plate  2  of the desk  1 , and serves to attach the network device  100  to the desk  1  at a predetermined angle with respect to the horizontal direction (90 degrees in FIG. 1). The top plate  2  projects towards the side in the desk  1 , and forms the space  4  under the projected part. The attachment instrument  200  effectively utilizes the space  4  in this embodiment. The attachment instrument  200  includes a support part  210 , an accommodation part  220 , and an engagement part  230 . The attachment instrument  200  of this embodiment is formed by bending one metal plate. Thereby, the attachment instrument  200  is easily manufactured.  
     [0042] The support part  210  supports the housing  101  of the network device  100 . The support part  210  has a perpendicular part  212 , a horizontal part  214 , and a pair of bent parts  216 . The perpendicular part  212  supports the left side surface  108  of the network device  100 . In one embodiment, the perpendicular part  212  serves as a heat radiator for the network device  100 . The perpendicular part  212  has a pair of holes  213  into each of which a bolt  219 , which will be described later, is inserted. The number of holes  213  is not two in an actual configuration, and attachment parts  134  to  138 , which will be described later, include corresponding holes, although these holes are omitted in FIG. 2A for simplicity purposes.  
     [0043] The perpendicular part  212  has a height H 1 , which is set to be higher than the network device  100 . The horizontal part  214  has a width W, which is set to be wider than the network device  100 . In one embodiment, in order to accommodate two or more network devices  100 , the width W of the horizontal part  214  is set to be twice as wide as that of the network device  100 . Thereby, the support part  210  may support two stackable hubs connected in a stack-connection manner. The bent parts  216  and  226  have a length L/3 in this embodiment.  
     [0044] The accommodation part  220  may accommodate the cable  130 . The accommodation part  220  accommodates the cable  130  and prevents littering of the cable  130 . The accommodation part  220  has a perpendicular part  222 , a horizontal part  224 , and a bent part  226 . The perpendicular part  222  has a height H 2 , which may accommodate the cable  130 . As the bent part  226  has a height H 3 , which is shorter than the height H 2 , an aperture  227  is formed between the horizontal part  224  and the bent part  226 . Thereby, the cable  130  may be inserted through the aperture  227  into the horizontal part  224 , and removed through the aperture  227  from the horizontal part  224 . When the bent part  226  has the height H 3  equal to the height H 2 , the cable  130  would be inserted into the accommodation part  220  through its end. Therefore, the instant embodiment improves operational performance.  
     [0045] The accommodation part  220  includes, as shown in FIG. 3, one or more cutouts  228  engaged with a bundler member  240  for bundling the cable  130  on the horizontal part  224 . For example, the bundler member  240  is formed as a tie or tie-wrap. Thereby, the cable  130  is definitely prevented from littering. The bundler member  240  fixes the cable  130 , and maintains a certain radius of curvature of the cable  130  when the cable  130  is an optical fiber cable, for example. Thus, the cable  130  is prevented from getting damaged. If necessary, a plurality of cutouts  228  may be provided in the direction of width W in FIG. 2B so as to bundle different types of cables  130  at the cutouts  228 .  
     [0046] The engagement part  230  is fixed onto an edge of the top plate  2 . The engagement part  230  of this embodiment has an approximately C shape for arranging the support part  210  inside the top plate  2  (i.e., in the space  4 ), and has a horizontal part  232 , a perpendicular part  234 , and a bent part  236 . The horizontal part  232  and the bent part  236  have the width W, while the perpendicular part  234  has a height H 4  slightly taller than the top plate  2  of the desk  1 . The bent part  236  includes a pair of holes  237  to which fittings  250  are inserted. A pair of fittings  250  each include a counter-sunk bolt  252 , a weld nut  254 , and a butterfly nut  256 . The counter-sunk bolt  252  contacts the lower surface of the top plate  2  of the desk  1  and fixes the engagement part  230  onto the top plate  2 . The height of the counter-sunk bolt  252  is adjustable.  
     [0047] The attachment instrument  200  of this embodiment further uses the fitting  280 , a pair of bolts  290 , and a pair of nuts  291 . Referring to FIGS.  4  to  6 , a description will now be given of the attachment parts  132  to  138  of the housing  101 . Here, FIG. 4 is a schematic perspective view of an external appearance of the network device  100  before the fitting  280  is attached to the housing  101 . FIG. 5 is a sectional view taken along a line A-A in FIG. 4. FIG. 6 is a schematic perspective view of an external appearance of the network device  100  after the fitting  280  is attached to the housing  101 . FIG. 7 is a sectional view taken along a line B-B in FIG. 6.  
     [0048] As shown in FIG. 5, each attachment part has the projection  140  and inlet  142 . The projection  140  is formed at an inner surface of each attachment part opposite to the housing  101  so that the projection  140  projects towards the housing  101 . The projection  140  is inserted into the hole  282  of the fitting  280 , which will be described later, and serves as a stopper for preventing the fitting  280  from falling off from the corresponding attachment part. Since the projection  140  may be separated from the hole  282 , it enables the fitting  280  to be engaged with a desired attachment part among the attachment parts  132  to  138 . An engagement part  281  of the fitting  280  is inserted into the inlet  142 .  
     [0049] The fitting  280  is made, for example, of heat-conductive and rigid stainless, and has, as shown in FIG. 4, a pair of engagement parts  281 , a pair of connection parts  283 , a base  284 , and an engagement part  286 .  
     [0050] The engagement part  282  is connected to the base  284  through the connection part  283  at the back of the base  284 . Each engagement part  281  exemplarily has a shape of a combination of a semi-circle and rectangle, and has the circular hole  282  at its approximate center thereof. The engagement part  281  is inserted into the inlet  142  of the corresponding attachment part, and the hole  282  engages with the projection  140  of the corresponding attachment part. Therefore, an interval between the engagement parts  281  is identical to that of the attachment part. Alternatively, the engagement part  281  may have a projection while the attachment part has a hole.  
     [0051] The connection part  283  is provided to maintain a space S for accommodating a head of the bolt  290  when the fitting  280  is attached to the attachment part, as shown in FIG. 7. The connection part  283  also serves as a stopper for supporting the corresponding attachment part. The bolt  290  engaged with the nut  291 . The base  284  has a pair of holes  285 . As shown in FIG. 7, the bolt  290  is inserted into the hole  213  of the perpendicular part  212  in the support part  210  through each hole  285 . A bolt  298 , which will be described later, is inserted into a bolt hole  288  for fixing the magnet  295 .  
     [0052] The engagement part  286  is used in a variation of this embodiment, which will be described later, and connected to and level with the base  284 . The same flat plane enables the rear surfaces of three magnets  295  (i.e., surfaces opposite to the fittings  280 ) to be flat when these three, same magnets  295  are used for the engagement parts  286 . Therefore, even when a particular magnet is made thicker and the engagement part  286  is provided at the back of the base  284 , the other surfaces of all the magnets  295  should form the same flat surface. The same flat surface is required to maintain horizontalness at the time of attachment of the housing  101  since the surface of the perpendicular part  212  is horizontal. The engagement part  286  has an exemplarily chamfered rectangular shape, and has a bolt hole  287  at an approximate center thereof. The bolt  298  is inserted into the bolt hole  287 , similar to the bolt hole  288 , for fixing the magnet  295 , which will be described later.  
     [0053] In attaching the housing  101  to the perpendicular part  212  of the support part  210 , the fitting  280  are fixed onto the perpendicular part  212  through two bolts  290 , nuts  291 , and holes  285  and holes  213 . Then, the engagement parts  281  are inserted into the inlets  142  of the attachment parts  132  to  138  so as to engage the projections  140  with the holes  282 . FIGS. 6 and 7 select the attachment parts  132 . As a result, the housing  101  may be attached to the perpendicular part  212  of the support part  210  in a desired orientation.  
     [0054] As discussed, when the attachment parts other than the attachment parts  132  are selected, the position of the hole  213  changes, although FIG. 2A omits such a hole for simplicity purposes. In other words, a user may freely determine a position and orientation of the housing  101  relative to the perpendicular part  212  based on wiring requirements and his preferences. One embodiment supports the network device  100  using only the perpendicular part  212 , i.e., without the horizontal part  214 . Of course, the present invention covers an embodiment that supports the network device  100  using only the horizontal part  214 , i.e., not the perpendicular part  212 .  
     [0055] Even when the projection  140  is disengaged from the hole  282 , the connection part  283  supports the housing  101 . Since the head of the bolt  290  is accommodated in the space S, the bolt  290  does not damage the rear surface of the housing  101 . The fitting  280  is made of heat-conductive material, and protects the electronic circuit in the housing by transmitting heat from the housing  101  to the perpendicular part  212 . Thus, the fitting  280  positions the housing  101  with the attachment parts  132  to  138  of the housing  101 , determines an orientation of the housing  101 , fixes the housing  101 , and radiates the heat from the housing  101 .  
     [0056] A description will now be given of a variation of the present embodiment with reference to FIGS.  8  to  10 . The instant embodiment also commonly uses the housing  101  and fittings  280 , although it uses the magnets  295  instead of the bolts  290 . This embodiment also fixes the housing  101  onto the perpendicular part  212 , although the attachment instrument of this embodiment includes a metal material, such as steel, which may fix a magnet. Here, FIG. 8 is a sectional view of magnet  295 . FIG. 9 is a perspective view of an external appearance of the network device  100  in which the fitting  280  and magnets  295  are attached to the housing  101 . FIG. 10 is a sectional view taken along a line B-B in FIG. 9. FIG. 6 is a view before the magnets  295  are attached to the fitting  280 .  
     [0057] The magnet  295  includes, as shown in FIG. 8, center holes  296  and  297  at its almost center. The center hole  296  accommodates, as shown in FIG. 10, the head of the bolt  298  for fixing the magnet  295  onto the fitting  280 . The center hole  297  has a diameter smaller than that of the center hole  296 , which allows the body of the bolt  298  to pass through but does not allow its head to pass through. The bolt  298  is coupled with the nut  299  through the bolt  298 .  
     [0058] In attaching the housing  101  to the perpendicular part  212 , the magnet  295  is first fixed onto the bolt holes  297  and  298  of the fitting  298  through the bolt  298  and nut  299 . Then, the fitting  280  is secured in place using a magnetic force by the magnet  295 . Preferably, the bottom surface  106  of the housing  101  contacts the support part  210  for stable supporting. Surfaces which all the magnets  295  face the perpendicular part  212  form the same flat surface, maintaining the horizontalness of the housing  101  and enhancing the fixture. This embodiment does not use the holes  213  in the perpendicular part  212 .  
     [0059] Then, the engagement parts  281  are inserted into the inlets  142  of a desired pair of attachment parts  132  to  138  so that the projections  140  may engage with holes  282 . FIGS. 9 and 10 select the attachment part  132 . As a result, the housing  101  may be attached to the perpendicular part  212  at a desired orientation. A user may freely determine the desired position on the perpendicular part  212  and the orientation of the housing  101  based on the wiring requirements and preferences. Even when the projection  140  is disengaged from the hole  284 , the connection part  283  supports the housing  101 . Since the nut  299  of the bolt  298  is accommodated in the space S, the bolt  290  does not damage the rear surface of the housing  101 . The fitting  280  is made of heat-conductive material and protects the electronic circuit in the housing by transmitting heat from the housing  101  to the perpendicular part  212 . Thus, the fitting  280  positions the housing  101  with the attachment parts  132  to  138  of the housing  101 , determines an orientation of the housing  101 , fixes the housing  101 , and radiates the heat from the housing  101 .  
     [0060] A description will now be given of another embodiment of the present invention with reference to FIG. 11. Here, FIG. 11 is a schematic perspective view of the drawer mechanism  200  of one embodiment according to the present invention. This embodiment enables the network device  100  to be drawn out of the horizontal part  214 . The drawer mechanism  300  includes a base  310  fixed inside the support part  210 , a drawer  320 , and one or more grips or handles  330  fixed onto a front surface of the drawer  320 .  
     [0061] The base  310  has a sectionally U shape, and a pair of grooves  312  that extend in a direction K. The drawer  320  has an almost rectangle parallelepiped having a pair of rails or convexes  322  that extend in the direction K at its outer sides, and the drawer  320  accommodates the network device  100 . Each convex  322  is inserted into the groove  312 , and slides along the groove  312 . The side  324  of the drawer  320  may be as tall as the perpendicular part  212  of the support part  200 , if necessary. Thereby, the left side  108  of the network device  100  may be fixed onto the side  324 . The grips or handles  330  facilitate movements of the drawer  320 .  
     [0062] As a result the network device  100  is movable relative to the support part  210  while placed on the drawer  320 . Therefore, even when the support part  210  is provided at the back of the desk  1 , the network device  100  is easily mounted, exchanged and removed by pulling the drawer  320  out of the support part  210 . A mechanism for adjusting or restricting the draw-out amount of the drawer  320  may use any structure known in the art so that the drawer  320  may be prevented from being fallen off from the base  310 , and thus a description thereof will be omitted.  
     [0063] A description will now be given of another embodiment of the present invention with reference to FIG. 12. Here, FIG. 12 is a schematic sectional view of an attachment instrument  200 A having a support part  210 A of another embodiment according to the present invention. The support part  210 A has horizontal parts  214 A and  214 B, wherein the horizontal part  214 B may be drawn out of the horizontal part  214 A. The support part  210 A includes the perpendicular part  212 , the horizontal part  214 A connected to the perpendicular part  212 , the horizontal part  214 B that is movable relative to the horizontal part  214 A, the bent part  216  connected to the horizontal part  214 B, and a pair of grips  217  fixed onto a front surface of the bent part  216 . Those elements in FIG. 12 which are the same as corresponding elements in FIG. 2 are designated by the same reference numeral, and a description thereof will be omitted.  
     [0064] In this embodiment, the horizontal parts  214 A and  214 B exemplarily have the same width W. Thereby, the horizontal parts  214 A and  214 B may mount two network devices  100 . The number of stack connections would determine drawing out of the horizontal part  214 B. If necessary, the horizontal part  224  may be configured to be drawn out according to the drawing out of the horizontal part  214 B. The grip  217  facilitates movements of the horizontal parts  214 B. Thereby, the desired number of network devices  100  may be mounted on the support part. A mechanism for adjusting or restricting the draw-out amount of the horizontal part  214 B may use any structure known in the art so that the horizontal part  214 B may be prevented from being fallen off from the horizontal part  214 A, and thus a description thereof will be omitted.  
     [0065] A description will now be given of a variation  300 A of the drawer mechanism  300  with reference to FIG. 13. Here, FIG. 13 is a schematic sectional view of the drawer mechanism  300 A. The drawer mechanism  300 A in this embodiment has two drawers  320 A, and the horizontal part  214 C in which these two drawers  320 A are provided have a width twice as wide as that of the horizontal part  214 . Two network devices  100  may be mounted for stack connection. Each drawer  320 A may accommodate one network device  100 , and be drawn out of the horizontal part  214 C independently. Those elements in FIG. 13 which are the same as corresponding elements in FIG. 11 are designated by the same reference numeral, and a description thereof will be omitted. Thereby, only a desired network device  100  may be attached and replaced without affecting another network device  100  and communication apparatus connected to it. In FIG. 13, two front parts  312  at the center may be integrated with each other.  
     [0066] A description will now be given of an attachment instrument  200 D of another embodiment according to the present invention with reference to FIG. 14. FIG. 14A is a schematic sectional view of the attachment instrument  200 D, and FIG. 14B is a plane view of the attachment instrument  200 D taken along a line F-F in FIG. 14A. The attachment instrument  200 D may be configured to expand the attachment instrument  200 E. Those elements in FIG. 14 which are the same as corresponding elements in FIG. 12 are designated by the same reference numeral, and a description thereof will be omitted.  
     [0067] The attachment instrument  200 D includes, as shown in FIG. 14B, a perpendicular part  212 D having a pair of attachment holes  218 . The attachment holes  218  of this embodiment have a rectangular shape with a height OH and a length OL. The attachment instrument  200 E does not necessarily have an engagement part  230 , and a properly rigid engagement part  219  is formed at each bent part  216 . The engagement part  219  has a horizontal part  219   a  and perpendicular part  219   b , and a sectionally hook shape as shown in FIG. 14A. The horizontal part  219   a  is formed at the center of the bent part  216 , while the perpendicular part  219   b  has a rectangular shape and is inserted into the attachment hole  218 . The attachment instrument  200 D may mount two network devices  100  when engaged with the attachment instrument  200 E and realize the stack connection. Each attachment instrument  200 D does not have to be unnecessarily large as far as it may accommodate at least one network device  100 .  
     [0068] A description will now be given of an attachment instrument  200 F of another embodiment according to the present invention with reference to FIG. 15. Here, FIG. 15A is a schematic plane view of the attachment instrument  200 F, and FIG. 15B is a schematic top view of the attachment instrument  200 F. In the attachment instrument  200 F, the relative angle between the support part  210 F and the engagement part  230 F is adjustable, as shown in FIG. 15B, by rotating an angle adjuster  242 . A support part  210 F has a horizontal part  211  parallel to and as large as the horizontal part  214 . The horizontal part  211  is formed instead of the bent part  236  at the top of the perpendicular pat  212 . Other than that, it has the same structure as the support part  210 .  
     [0069] The angle adjuster  242  has a shaft that may rotate relative to one of a support parts  210 F and an engagement part  230 F and may not rotate relative to the other, and an operation part on a gear fixed around the shaft. The user may adjust the relative angle between them by rotating the operation part using a finger. A structure to fix the relative angle between them to a predetermined angle may use any structure known in the art, and thus a description thereof will be omitted.  
     [0070] The attachment instrument  200 F may facilitate the effective use of the space  4  by adjusting the relative angle between the support part  210 F and the engagement part  230 F using the angle adjuster  242  according to a shape of the space  4 , a thing located in the space, user&#39;s preference and operational performance.  
     [0071] A description will now be given of an attachment instrument  200 G of another embodiment according to the present invention with reference to FIG. 16. Here, FIG. 16 is a schematic sectional view of the attachment instrument  200 G. The attachment instrument  200 G may three-dimensionally adjust the relative angle between a support part  210 G and an engagement part  230 G by rotating an angle adjuster  244 . The support part  210 G is parallel to and as large as the horizontal part  214 , like the support part  210 F.  
     [0072] The angle adjuster  244  includes a ball that may rotate relative to one of the support parts  210 G and engagement part  230 G and may not rotate relative to the other, and an operation part on a gear fixed around the shaft.  1 The user may adjust the relative angle between them by rotating the operation part  210 G using a finger. A structure to fix the relative angle between them to a predetermined angle may use any structure known in the art, and thus a description thereof will be omitted.  
     [0073] The attachment instrument  200 G may facilitate the effective use of the space  4  by adjusting the relative angle between the support part  210 G and the engagement part  230 G using the angle adjuster  244  according to a shape of the space  4 , a thing located in the space, user&#39;s preference and operational performance.  
     [0074] The above embodiments change angles of the support parts  210 F and  210 G to the engagement parts  230 F and  230 G, but the engagement part  230  may be angled to the desk  1 . Thereby, an adjustment of a relative angle between the support part and the engagement part according to shapes of the installation space would promote the effective use of the installation space.  
     [0075] A description will now be given of an attachment instrument  200 H of another embodiment according to the present invention with reference to FIG. 17. Here, FIG. 17 is a schematic sectional view of the attachment instrument  200 H. This embodiment enables the support part  210 H to be drawn out of the engagement part  230 H, and thus the network device  100  may be drawn out of the engagement part  230 H. The support part  210 H is parallel to and as large as the horizontal part  214 , like the support part  210 F. A drawer mechanism  260  includes a guide  262 , a rail  264 , and a connection part  266 .  
     [0076] The guide  262  is fixed to the bent part  236  of the engagement part  230 H, and extends by a length L in the longitudinal direction of an engagement part  239 H. The guide  262  guides and holds the rail  264 . The guide  262  is so constricted that the rail  264  does not move longitudinally. The rail  264  is provided in the guide  262  so as to be drawn out of the guide  262 , and made movable relative to the guide  262 . The rail  262  extends by the length L, in the longitudinal direction of the guide  264 . The connection part  266  connects the rail  264  and the support part  210 H to each other. If necessary, a grip (not shown) is formed on the support part  210 H.  
     [0077] As a result, the network device  100  may move relative to the engagement part  230 H while mounted on the support part  210 H. Thereby, even when the engagement part  230 H is provided at the back of the desk  1 , the network device  100  is easily mounted, exchanged and removed by drawing the support part  210 H out of the engagement part  23011 . A mechanism for adjusting or restricting the draw-out amount of the rail  264  may use any structure known in the art so that the support part  210 H may be prevented from being fallen off from the engagement part  230 H, and thus a description thereof will be omitted.  
     [0078] The above embodiment changes an angle of the support part  210 H to the engagement parts  230 H, but the engagement part  230  may be angled to the object or desk  1 . Thereby, even when the engagement part is located at the back of the object, the network device is easily installed and exchanged by drawing out the engagement part. A structure for making the engagement part  230  movable relative to the desk  1  may use any structure known in the art, for example, by using wheels instead of the fittings  250 , and thus a detailed description thereof will be omitted.  
     [0079] Further, the present invention is not limited to these preferred embodiments, and various modifications and variations may be made without departing from the scope of the invention. For example, a shape of the engagement part  230  is variable according to a shape of the object (for example, a curved surface). In addition, the present invention does not limit the object to be fixed by the engagement part to a horizontal member, such as a top plate of a desk, but may cover various connections to angled objects.  
     [0080] Thus, one aspect of the present invention may provide an attachment mechanism that may effectively utilize the installation space of the network device and bundle the cable for the network device.