Abstract:
Disclosed is a private branch exchange (PBX) that offers high efficiency in wiring cables, at the same time, protects cables in highly safety manner. The PBX includes a PBX section and a casing that covers and holds the PBX section. The casing contains an inner-bottom plate, a support column, and a pedestal. Cables for connections with external circuitry can be connected to the PBX section on the front side of the interior of the casing. The inner-bottom plate holds the bottom of the portion of the casing on which the PBX section is accommodated. The support column is disposed on the lower surface of the inner-bottom plate. Disposed beneath the support column, the pedestal holds the entire of the casing. The support column has a curved surface on the front side, protecting cables wired between the inner-bottom plate and the pedestal.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a private branch exchange (PBX) that allows a plurality of terminals to make an extension call or an outside call. More particularly, it relates to a PBX that offers easy wiring for cables to be connected to the terminals.  
         BACKGROUND OF THE INVENTION  
         [0002]    Recently, a private branch exchange (PBX) has been widely used in a local area, such as in an office and a building. Connected to a PBX via cables, a plurality of telephones disposed in such an office and a building make an extension call with each other, or make an outside call via a public telephone line.  
           [0003]    In making an extension call or an outside call, a PBX works as follows:  
           [0004]    (1) In making an extension call, the PBX offers connection between specific terminals among a plurality of terminals such as telephones connected via cables.  
           [0005]    (2) In making an outside call, the PBX offers connection between a terminal and a public telephone line.  
           [0006]    In PBXs described above, free-slot type PBXs have been widely used. The free-slot type PBX contains a plurality of terminal cards each of which has a link-up connector. The link-up connectors are mounted on a plurality of shelves formed in a casing so that each connector is disposed in the front side of the casing. Each terminal card, which is removably fixed on a backboard disposed behind in the interior of the casing, is exchangeable and expandable in number.  
           [0007]    The free-slot type PBX is able to accept an add-on terminal card corresponding to a terminal additionally connected to the PBX. This allows the PBX to be ready for an increase in the number of terminals connected thereto, with no need for an extra PBX.  
           [0008]    The casing as the exterior of the free-slot type PBX usually has a generally rectangular parallelepiped shape. Terminals of the link-up connectors for connecting to terminals including telephones are disposed in the front side of the casing of each terminal card. A removable or retractable front cover is disposed in front of the casing so as to cover the front at which the linkup connectors are disposed. The structure described above provides the PBX with ease of use and an improved exterior.  
           [0009]    In installing a PBX, cable-wiring is generally done below.  
           [0010]    The cable connected with a link-up connector passes through a clearance formed between components in the casing to go outside from behind or a side of the casing. A front cover covers the front of the casing, which enhances safety in operation and offers a neat appearance.  
           [0011]    Now will be described a prior-art PBX with reference to the accompanying drawings.  
           [0012]    [0012]FIG. 5 is a perspective view indicating the essential part of a prior-art typical PBX.  
           [0013]    In typical PBX  21  shown in FIG. 5, top cover  22  forms the top surface of a casing; similarly, front cover  23  and side cover  24  form the front and the side surfaces of the casing, respectively.  
           [0014]    Front cover  23  is removably fixed to PBX  21  by screws or the like, or may be retractably formed.  
           [0015]    [0015]FIG. 6 is a front view indicating the essential part of the prior-art PBX with a front cover removed.  
           [0016]    In PBX  21  shown in FIG. 6, elements similar to those shown in FIG. 5, such as top cover  22  and side cover  24 , have the same reference numbers, and descriptions of those elements are omitted.  
           [0017]    Shelves  26  are formed in the casing so as to have at least a plurality of shelves each of which has an opening on the front side of PBX  21 . Terminal cards  27  are slotted into each of shelves  26 . Link-up connectors  28  are disposed on the front side of each of terminal cards  27 . Cables  29  are connected with each of connectors  28 . A clearance formed between components disposed in the interior of the casing forms cable path  30 .  
           [0018]    Terminal cards  27  include an extension-call unit card and an outside-call unit card that have a telephone-exchange function. The cards are removably slotted into PBX  21  in such a manner that the link-up connectors of the cards are placed on the front side of the casing of PBX  21 .  
           [0019]    Here will be described the wiring of cables  29  in such structured prior-art PBX, referring to the accompanying drawing.  
           [0020]    Cables  29 , as shown in FIG. 6, are wired from the front side of the casing, through cable path  30  disposed in the interior of the casing, to the rear side of the casing.  
           [0021]    Prior to the wiring of cables  29 , front cover  23  is removed. After connected with link-up connectors  28 , cables  29  are wired through cable path  30 . Then, removing front cover  23  only has not offered to an operator with enough room for wiring cables  29  due to the small-sized openings of cable path  30 . Therefore, the operator removes side cover  24  and a back cover (not shown) to wire cables  29  through cable path  30  from the side of the casing.  
           [0022]    That is, the prior-art PBX has inconveniencies as follows:  
           [0023]    (1) The prior-art PBX imposes described below on the operator: for wiring cables through the interior of the casing, the operator removes or opens the front cover; then removes the side cover and the back cover from the side and the rear of the casing of the PBX; then wires the cable through the clearance formed between components disposed in the casing. The process above has been repeatedly performed. Such bothersome work has thus lowered efficiency in wiring and maintenance work.  
           [0024]    (2) The prior-art PBX has used, as the cable path, the clearance formed between components disposed in the casing. In the casing, there are opened metals or the like, which form components disposed in the casing. Therefore, in the works, care is needed in wiring cables without causing defects from contacting other components in the casing.  
         SUMMARY OF THE INVENTION  
         [0025]    It is therefore the object of the present invention to provide a private branch exchange (PBX) that offers a highly efficient cable-wiring with and cable-protection.  
           [0026]    The PBX of the present invention includes a private branch exchange (PBX) section and a casing that serves as a cover and holder for the PBX section. The casing further includes an inner-bottom plate, support column, and a pedestal. A cable that provides outside connection can be connected to the PBX section at the front side of the interior of the casing.  
           [0027]    The inner-bottom plate holds the bottom portion of the casing on which the PBX section is mounted. The support column is disposed on the lower surface of the inner-bottom plate. Disposed beneath the support column, the pedestal holds the entire of the casing. The front side of the support column is formed into a curved surface so as to protect the cable wired between the inner-bottom plate and the pedestal.  
           [0028]    The structure described above allows the cables connecting between the PBX and terminals to be easily wired from the front to the side or rear of the PBX. Besides, only removing the front cover allows wiring to be performed without removing the side cover form the casing. Accordingly, the PBX provides efficiency in works for the maintenance and wiring. Furthermore, the PBX having the structure above protects the cables wired in safe manner, in the wiring works. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]    [0029]FIG. 1 is a perspective view indicating the essential part of a private branch exchange (PBX) in accordance with a first preferred embodiment of the present invention.  
         [0030]    [0030]FIG. 2 is a front view indicating the essential part of the PBX with a front cover removed in accordance with the first preferred embodiment.  
         [0031]    [0031]FIG. 3 is a cross-sectional view of the PBX, taken along line A-A in FIG. 2, looking in the direction of the arrows.  
         [0032]    [0032]FIG. 4 is a perspective view of the PBX with the essential part enlarged in accordance with the first preferred embodiment.  
         [0033]    [0033]FIG. 5 is a perspective view indicating the essential part of a prior-art PBX.  
         [0034]    [0034]FIG. 6 is a front view indicating the essential part of the prior-art PBX with a front cover removed. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0035]    A preferred embodiment of the present invention is described hereinafter with reference to the accompanying drawings.  
         [0036]    [0036]FIG. 1 is a perspective view indicating the essential part of a private branch exchange (PBX) in accordance with the first preferred embodiment of the present invention.  
         [0037]    In PBX  1  shown in FIG. 1, top cover  2 , front cover  3 , and side cover  4  form the top, the front, and the side surfaces, respectively, of a casing of PBX  1 . Plate-like pedestal  5  forms the bottom of the casing of PBX  1 . Pedestal side-rises  6  are formed under side-cover  4 . Side-rises  6  are placed integrally with pedestal  5  at the both sides of pedestal  5  and stand substantially vertical to pedestal  5 . Projection  7  forms an end of pedestal  5  on the rear side of PBX  1 , protruding outwardly beyond the rear of the casing. The lower end of side cover  4  is notched to form shallow U-shaped finger-notch  8 . Side cover  4  and side-rises  6  have clearance  9  therebetween.  
         [0038]    Front cover  3  is disposed over PBX  1  so as to be removable by screws, or to be formed as a retractable cover.  
         [0039]    Projection  7  is integrally formed with pedestal  5  so that the rear end protrudes outwardly beyond the rear of the casing. When PBX  1  is mounted on a wall, PBX  1  is disposed maintaining a distance from the wall by the protruding length of projection  7 . This protects the rear of the casing of PBX  1  from contacting the wall or the like.  
         [0040]    Projection  7  may be formed by outwardly protruding a portion of the rear end of pedestal  5 , for example, a portion close to the middle or both ends of pedestal  5 .  
         [0041]    Pedestal  5  is preferably formed into a shape generally the same as that of top cover  2 , thereby a plurality of PBXs  1  can be formed into a stacking arrangement. This can save the installation space for PBX  1 .  
         [0042]    Clearance  9  formed between pedestal side-rises  6  and side cover  4  is enough wide so as to pass through cables, as that will be described later. However, an oversized width of clearance  9  is not necessary so as not to ruin the appearance of PBX  1 .  
         [0043]    Finger-notch  8  is formed by cutting out the lower edge of side cover  4  in a shallow U-shape. When the operator moves PBX  1 , the operator&#39;s hands touch the portion that is cut for forming finger-notch  8 . Therefore, the cutting edge of finger-notch  8  should preferably be smoothly formed.  
         [0044]    [0044]FIG. 2 is a front view indicating the essential part of the PBX with a front cover removed in accordance with the first preferred embodiment.  
         [0045]    In PBX  1  shown in FIG. 2, portions similar to those shown in FIG. 1, that is, top cover  2 , side cover  4 , pedestal  5 , side-rises  6 , and clearance  9  have the same reference numbers, and descriptions of those are omitted.  
         [0046]    Shelves  11  are formed in the casing so as to have at least a plurality of shelves each of which has an opening on the front side of PBX  1 .  
         [0047]    The PBX section is accommodated in the casing. The PBX section includes components indispensable for the PBX function, such as terminal cards  13 , link-up connectors  14 , and power supply unit  15 .  
         [0048]    Terminal cards  13  are slotted into each of shelves  11 . Each of connectors  14  is disposed on the front side of each terminal card  13 . Power supply unit  15  supplies power to PBX  1  disposed in the interior of the casing.  
         [0049]    Inner-bottom plate  18  of the casing, together with top cover  2  and side cover  4 , forms a clearance to accommodate shelves  11  and power supply unit  15  therein. At the same time, plate  18  holds the bottom portion of shelves  11  and power supply unit  15 . Top cover  2  and side cover  4  are also held from the underneath by plate  18 .  
         [0050]    Integrally formed with pedestal  5 , column-shaped support column  12  is generally centered on the upper surface of pedestal  5 . Column  12  supports inner-bottom plate  18 .  
         [0051]    Support column  12 , as described above, is formed in one-piece structure with pedestal  5  at a general center of pedestal  5 . Pedestal  5  and support column  12  are made of metal or synthetic resin.  
         [0052]    Preferably, the components forming the casing of PBX  1 —top cover  2 , front cover  3 , side cover  4 , and inner-bottom plate  18 —are made of the same material as that forming pedestal  5  and support column  12 . This provides PBX  1  with a good appearance.  
         [0053]    Terminal card  13  is an extension unit card or outside-call unit card having a telephone-exchange function or the like. Each card is removably slotted into shelves  11  in such a way that the ling-up connector is placed in the front side of the casing of PBX  1 .  
         [0054]    [0054]FIG. 3 is a cross-sectional view of the PBX, taken along line A-A in FIG. 2, looking in the direction of the arrows.  
         [0055]    In PBX  1  shown in FIG. 3, elements similar to those shown in FIGS. 1 and 2, namely, pedestal  5 , side-rises  6 , projection  7 , and support column  12 , have the same reference numbers, and descriptions of those are omitted.  
         [0056]    Support column  12  is preferably formed into a general cylindrical column or a general elliptic column having no corners on both sides or on the front thereof. This protects cables from causing scratches and other defects during wiring work as described later.  
         [0057]    In the first preferred embodiment, support column  12  has a general oval shape in section on the front side only.  
         [0058]    The support column, as described above, has a smooth curve at least on the front side on which the cables run through. Such curved surface protects the cables from causing scratches and other defects even if the cables contact with the surface during wiring work.  
         [0059]    The cables are wired from the front side to the rear side of the PBX. Therefore, the support column preferably has a curved surface at least on the front to the side of the column on which the cables run through.  
         [0060]    [0060]FIGS. 1, 2, and  3  do not show the cables of communication terminals (typically telephones) that are connected to link-up connectors  14 .  
         [0061]    Now will be described how to wire the cables in the PBX having the structured above of the first preferred embodiment, referring to the accompanying drawings.  
         [0062]    [0062]FIG. 4 is a perspective view of the PBX with the essential part enlarged in accordance with the first preferred embodiment.  
         [0063]    [0063]FIG. 4 shows the PBX with the front cover removed—the front cover is not shown in the figure.  
         [0064]    In PBX  1  shown in FIG. 4, portions similar to those shown in FIGS. 1 and 2, namely, side cover  4 , pedestal  5 , side-rises  6 , projection  7 , and finger-notch  8 , clearance  9 , shelves  11 , support column  12 , terminal card  13 , link-up connector  14 , and inner-bottom plate  18  have the same reference numbers, and descriptions of those are omitted.  
         [0065]    Cable  16  is connected with link-up connector  14 . Cable  16  may be a bunch of lead wires to be connected to a telephone and other terminals, or may be a fiber-optic cable connected to a plurality of communication terminals.  
         [0066]    To add slot terminal card  13 , the operator removes front cover  3  from PBX  1  and then inserts the card into a vacant slot of shelves  11  in PBX  1 .  
         [0067]    Link-up connector  14  of terminal card  13  is supposed to connect with one end of cable  16  and the other end of the cable is for connecting to the terminals including a telephone (not shown).  
         [0068]    [0068]FIG. 4 shows the state in which terminal card  13  is inserted into the rightmost slot seen from the front side of PBX  1 . In the state, cable  16  hangs down on the front side of PBX  1 .  
         [0069]    The operator now leads a part of cable  16  into the interior of side cover  4  from the outside—moves the part of the cable in the direction B—so as to run through clearance  9 . As a result, cable  16  runs, as shown in FIG. 4, from the front through the interior to the side or the rear of PBX  1 . After the wiring, the operator reinstalls front cover  3  to PBX  1 .  
         [0070]    The wiring of cable  16  from the front to the side or the rear of PBX  1  now completes.  
         [0071]    In the wiring work, pedestal side-rises  6  keep cable  16  running from the front to the side or the rear against moving outside of the casing. Accordingly a proper wiring of cable  16  can be performed in reliable manner.  
         [0072]    As described above, pedestal side-rises  6  stand up toward the side surface of the casing through a clearance. The structure can keep the cables inside of PBX  1 , coping well with the increase in cables wired.  
         [0073]    Besides, pedestal side-rises  6  is disposed so as to cover the cables wired, so that the cables wired inside are not seen from the outside. This provides PBX  1  with an improved appearance.  
         [0074]    [0074]FIG. 4 shows, for simplicity, the state in which only one cable is wired. It will be understood that, in the practical use, cables  16  which correspond to terminal cards  13  slotted into shelves  11  respectively are wired from the front to the side or the rear of PBX  1 .  
         [0075]    According to the embodiment of the present invention, the PBX with the structure described above offers benefits as follows:  
         [0076]    (1) Because the PBX has column  12 , cables  16  can be wired from the front of PBX  1  through the clearance formed on the side of column  12  to the side or the rear of PBX  1 . Besides, when cables  16  are wired, there is no need to remove side cover  4  disposed on the side of PBX  1  for wiring, enabling easy wiring work.  
         [0077]    (2) When PBX  1  is mounted on the wall, projection  7  allows PBX  1  to keep a predetermined interval between the wall and the rear of the casing. In the wiring of cable  16  from the front to the side of PBX  1 , the structure offers enough room for passing cable  16  on the side of PBX  1 . In this way, even in the case that a plurality of cables  16  is wired, the wiring is easily performed.  
         [0078]    (3) Pedestal side-rises  6  protect cables  16 , which are wired through the clearance formed on the side of support column  12 , from moving outside the casing. Creating clearance  9  so as to be barely wide enough for passing cable  16  allows cables  16  to be not seen from the outside. This provides PBX  1  with an improved appearance.  
         [0079]    (4) The structure has finger-notch  8 , therefore, engaging fingers in notch  8  to hold the PBX, the operator can easily carry PBX  1  in installation including add-on installation or maintenance work.  
         [0080]    (5) The structure offers spaces required for wiring work at the both sides, therefore, in the wiring work, the operator can use both of, or one of the spaces according to the circumstances in which the PBX is installed.  
         [0081]    Although the first preferred embodiment introduces a free-slot type PBX, it is not limited thereto. The PBX having a plurality of cable connections on the front side can offer the same effect according to the present invention.  
       INDUSTRIAL APPLICABILITY  
       [0082]    The PBX of the present invention, as described above, has industrial applicability below.  
         [0083]    (1) The operator can wire cables from the front of the PBX, through a clearance formed on the side of the support column, to the rear or the side of the PBX. In addition, the operator can easily wire the cables without removing the side-mounted side cover or the rear-mounted back cover from the casing in the wiring or maintenance work. The PBX of the present invention thus enhances efficiencies in wiring and maintenance work.  
         [0084]    The PBX has a support column whose front-side surface is formed into a smooth curve. The structure protects cables from causing defects even if the cables contact with the column while the wiring-work. As the result, the PBX offers easy wiring work.  
         [0085]    The pedestal side-rises keeps the cables, which are wired through the clearance on the side of the support column-side, from going away from to the outside. Further, the side-rises provide the PBX with good appearance.  
         [0086]    Even in case that a bunch of cables are wired, the side-rises keep the cables from going away to the outside. Thus the PBX with high efficiency in wiring work is provided.  
         [0087]    In addition, the side-rises are disposed on both sides of the pedestal so as to cover the cables wired, so that the cables are not seen from the outside Thus the PBX with an improved appearance is provided.  
         [0088]    The structure has the finger-notches. Accordingly, there is no need to form something to be held by hands. Therefore the appearance is not spoiled. In installation including add-on installation and maintenance work, the operator can easily move the PBX, by holding the notches. Thus the PBX offering easy carry is provided  
         [0089]    The PBX has the center-disposed support column and the clearance for wiring cables on both sides of the column. As the installation circumstances demand, the operator can wire the cables through the clearance on either side, or both sides of the column. Such structure provides the PBX which is easily used.