Abstract:
An improved cable preparation tool and an accompanying method which, when utilized concurrently, prepare fully shielded cables for termination into connecting devices. A preferred embodiment of the tool has hinged first and second tool handles biased together about a hinge by a resilient member. One end of a tool handle is fitted with a receptacle to receive and mount a detachable blade cartridge assembly which cuts the cable jacket and shielding metallic foils wrapped around individual pairs of insulated wires. A second receptacle is provided in either tool handle to receive a detachable template cartridge assembly which is used to properly position wires for termination into a connector. An exemplary method of cable preparation using the tool includes removing a cutting a cable jacket, cutting a plurality of foils and aligning wires using a single cable preparation tool.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. provisional patent application serial No. 60/110,296 filed Nov. 30, 1998, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to cable preparation tools, specifically to an improved tool and an accompanying method which, when utilized concurrently, prepare fully shielded cables for termination into connecting devices. 
     Improvements in telecommunications systems have resulted in the ability to transmit voice and/or data signals along transmission lines at increasingly higher frequencies. Several industry standards specify that multiple performance levels of twisted-pair cabling components have been established. The primary references, considered by many to be the international benchmarks for commercially based telecommunications components and installations, are standards ANSI/TIA/EIA-568-A (/568), Commercial Building Telecommunications Cabling Standard, and 150/IEC 11801 (/11801), Generic Cabling for Customer Premises. 
     Standards /568 and 11801, as well as other existing national and regional standards, specify use of category  3 , 4  and  5  cable and connecting hardware. In these specifications, transmission requirements for Category  3  components are specified up to 16 MHZ. Transmission requirements for Category  4  components are specified up to 20 MHZ. Transmission requirements for Category  5  components are specified up to 100 MHZ. 
     New standards are being developed continuously and currently it is expected that future standards will require transmission requirements of at least 600 MHZ. To achieve such transmission rates, fully shielded twisted pair cable, as shown generally at  10  in FIG. 1, will be necessary. Such cable contains individual insulated wires  16  that are paired with each pair being wrapped in a metallic foil  18 . Then the pairs are wrapped together in another layer of foil or screen  14 , and finally bound within an insulative jacket  12 . 
     The above referenced transmission requirements also specify limits on near-end crosstalk (NEXT). Telecommunications connectors are organized in sets of pairs, typically made up of a tip and ring connector. As telecommunications connectors are reduced in size, pairs are placed closer to each other creating NEXT between adjacent pairs. 
     To comply with the NEXT requirements, a variety of techniques are used in the art. U.S. patent application Ser. No. 09/047,046, now U.S. Pat. No. 6,224,423, incorporated herein by reference, describes an enhanced performance telecommunications connector, appearing generally at  20  in FIG. 2, which utilizes overlapping shield members to provide enhanced shielding and reduced crosstalk in the mating of fully shielded cable connectors. 
     FIG. 3 depicts an exemplary process for installing a cable  10  in a connector  20 . The cable is first prepared as shown in FIG. 4. A length (shown as A) of the cable jacket  12  is removed. Then, a second length (shown as B) of the metallic foil  18  is removed. As shown in FIG. 3, the individual wires  16  are aligned and then inserted into termination caps  22 . The termination caps  22  are then clamped down to terminate wires  16  on insulation displacement contacts in connector  20 . 
     Traditional methods of preparing fully shielded cable for connector installation require the installer to take measurements by hand, execute multiple stripping actions using several tools, including sharp blades, and arrange wires  16  by hand for insertion into connector. Distances A and B are typically hand measured by the installer. Conventional cable preparation tools, such as that illustrated in FIG. 5 or that produced by Sargent Tool Company, commercially available as ‘8700 Easy Strip Compress Tool’, can be used to remove cable jacket  12 . Such conventional tools, however, fail to assist the installer in removing foils  18  and aligning inner wires for insertion into connector. A straight blade, such as a knife or scissors, is traditionally used to individually remove metallic foil  18 . Then the installer must visually align wires  16  by hand for insertion into termination caps  22 . 
     Prior art methods of cable preparation involve several tools, multiple steps and result in considerable installation time. Removal of metallic foil  18  by use of an open blade exposes the installer to safety hazards and threatens the severance of individual insulated wires  16 . Once wires  16  are exposed, the cable must be installed in the connector. Manual arrangement of wires  16  is time consuming and subject to installer error. If the wires are inserted improperly into the connector, the connector will fail to function properly and additional time and resources will be consumed in making the appropriate corrections. Hence, the need has arisen for a invention which allows a fast, simple, and safe method of preparing fully shielded cable for connector termination by use of one, low-cost tool. 
     SUMMARY OF THE INVENTION 
     The above-discussed and other drawbacks and deficiencies of the prior art are overcome or alleviated by the cable preparation tool and cable preparation method of the present invention. The cable preparation tool is designed for use with shielded cable including a plurality of pairs of wires, each pair of wires surrounded by a metallic foil. The tool includes first and second tool handles, a blade assembly, and a template assembly provided in one of said first and second tool handles. A method of preparing the shielded cable includes inserting the cable in a cutting portion of the tool and cutting the cable jacket using the tool. The outer cable jacket is removed and the pairs of wires are placed in the cutting portion of the tool. Each of the foils is cut in one step using the tool. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring now to the drawings wherein the like elements are numbered alike in the several FIGURES: 
     FIG. 1 is a perspective view of a conventional fully shielded cable; 
     FIG. 2 is a perspective view of a connector for use with the fully shielded cable of FIG. 1; 
     FIG. 3 is perspective view of the process for connecting the cable of FIG. 1 with the connector of FIG. 2; 
     FIG. 4 illustrates the cable of FIG. 1 prepared for installation with the connector of FIG. 2; 
     FIG. 5 is a side view of a conventional tool for removing the jacket from the cable of FIG. 1; 
     FIG. 6 is a perspective view of a cable preparation tool in an exemplary embodiment of the invention; 
     FIGS. 7A,  7 B, and  7 C depict perspective, top and bottom views, respectively, of the template cartridge assembly  142  contained in tool  100  of FIG. 6; 
     FIGS. 8A,  8 B, and  8 C depict front, top, and bottom views, respectively, of blade cartridge assembly  122  contained in tool  100  of FIG. 6; 
     FIGS. 9-13 are perspective views illustrating the method of preparing fuilly shielded cable for connector termination using the tool of FIG. 6; 
     FIG. 14 is a perspective assembled view of a tool in an alternative embodiment of the invention; 
     FIG. 15 is a perspective exploded view of the tool of FIG. 14; 
     FIGS. 16-19 are perspective views illustrating the preparation of a fully shielded cable for connector termination using the tool of FIG. 14; 
     FIG. 20 is a perspective view of detachable tool head  220 ; 
     FIG. 21 is a plan view of contact surface  245  of detachable tool head  220 ; 
     FIG. 22 is a perspective view of second detachable tool head  300 ; 
     FIG. 23 is a plan view of contact surface  312  of second detachable tool head  300 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 6 is a perspective view of a cable preparation tool shown generally at  100  as an exemplary embodiment of the present invention. Tool  100  includes tool handles  102  and  104  which are pivotally joined at a hinge  106 . Handle  102  has a tool head end  110  and handle  104  has a tool head end  112 . Tool handle  102  has a grip end  114  and handle  104  has a grip end  116 . Grip end  116  contains a finger bore hole  118 . Positioned between grip end  114  and grip end  116  is a resilient member  108 . Resilient member  108  biases tool head ends  110  and  112  towards each other as described in further detail herein. A detachable blade cartridge assembly  122  is mounted to tool handle  104  at tool end  112 . Blade cartridge assembly  122  includes a blade  136 , as shown in FIG. 8B, for scoring the jacket  12  and the foils  18  of shielded cable  10 . Blade cartridge assembly  122  contains semi-cylindrical channel  134  and area of enlarged radius  132  which are positioned opposite semi-cylindrical channel  120  of tool handle  102 . A detachable template cartridge assembly  142  is mounted to tool handle  104  at cartridge receptacle  143 . Template cartridge assembly  142  allows the installer to properly position wires  16  for installation into connector as described in further detail herein. Cartridge receptacle  143  is shaped approximately congruent to insertion side  145  (see FIG. 7C) of template cartridge assembly  142 . Cartridge receptacle  143  is sized slightly larger than template cartridge assembly  142  to allow insertion of the latter into the former while still maintaining sufficient friction between contacting surfaces to prevent cartridge dislodgment during tool  100  usage. 
     FIG. 7A depicts a perspective view of template cartridge assembly  142 . Template cartridge assembly  142  is comprised of cartridge base  152  upon which a planar extension  150  and an angled extension  148  are mounted. Planar extension  150  contains a semi-cylindrical cut-out  157  to aid in the separation and positioning of wires  16  when inserted into template cartridge assembly  142  in preparation of termination with a connector. Angled extension  148  contains indicia  146  discussed below. Planar extension  150  and angled extension  148  are mounted on cartridge base  152  perpendicular to each other such that four sectors  151  are formed. Funnels  149  are bored into cartridge base  152  in each sector  151 . Funnels  149  are conical in shape and taper to holes  144  to guide wires  16  into holes  144  during use of template cartridge assembly  142 . The height of angled extension  148  above base  152  and height y of base  152  are established so that a predetermined length of wire extends from the cable jacket  12  after cable preparation as described herein. 
     FIG. 7B is a top view of template cartridge assembly  142 . Cartridge base  152  contains eight holes  144  paired in each sector  149 . Angled extension  148  contains indicia  146  corresponding to each of the eight holes  144 . Indicia  146  may be comprised of color codes, words, and/or symbols and may be used to instruct the installer in the proper positioning of each wire  16  for termination into one or several connector types. 
     FIG. 7C is a bottom view of template cartridge assembly  142 . Template cartridge assembly  142  is placed in cartridge receptacle  143  for use with tool  100  as discussed more fully herein. The bottom  145  of cartridge base  152  includes exit holes  144 ′ which correspond to holes  144  of FIG.  7 B. 
     FIG. 8A depicts a front view of blade cartridge assembly  122 . Indicia  139  is embossed on front wall  138 . Indicia  139  may be comprised of words, symbols, and/or color codes and may indicate the proper direction to direct fully shielded cable  10  onto template blade cartridge assembly  122  when preparing cable for connector installation. Guide rails  137  are mounted on first and second side walls  133  and  135 . Contact surface  131  contains semi-cylindrical channel  134  and an area of enlarged radius  132 . Stop tab  130  extends from front wall  138  in a direction opposite contact surface  131 . Stop tab  130  is a safety precaution which prevents cartridge slippage and blade mishandling during tool usage. 
     FIG. 8B is a plan view of contact surface  131  of blade cartridge assembly  122 . A blade  136  is positioned in semi-cylindrical channel  134  a determined distance from area of enlarged radius  132 . This distance corresponds to the length of metallic foil  18  required to remain on each pair of individual insulated wire  16  after scoring, as discussed below in conjunction with FIGS. 10 and 11. Blade  136  is set into blade cartridge assembly  122  to prevent unintended contact with the blade but still allow proper scoring of outerjacket  12  and metallic foils  18 . 
     FIG. 8C is a plan view of the bottom surface  140  of blade cartridge assembly  122 . Bottom surface  140  is arranged opposite contact surface  131 . Blade base  136 ′ mounted to side walls  133  and  135  via mounting members  141 . 
     Use of tool  100  will now be described. FIGS. 9A and 9B depict the removal of the cable jacket  12  using tool  100 . Handles  102  and  104  of tool  100  are depressed towards each other to spread tool ends  110  and  1   12  apart. Cable  10  is placed in semi-cylindrical channel  134 , as shown in FIG. 9A, so that blade  136  contacts cable jacket  12  approximately thirty-five to fifty millimeters from the end to be terminated of fully shielded cable  10 . Tool handles  102  and  104  are then released. Tool ends  110  and  112  are biased together by resilient member  108  pressing blade  136  against jacket  12 . Tool  100  is then rotated around cable  10  to score cable jacket  12 . Scored jacket  12  is removed by hand and metallic braid  14  is folded back at scored jacket edge  15 , as shown in FIG. 9B, exposing wires  16  wrapped in metallic foils  18 . 
     FIGS. 10A and 10B depict the scoring of metallic foil  18  using tool  100 . Handles  102  and  104  of tool  100  are depressed towards each other to spread tool ends  110  and  112  apart. The four pairs of wires  16 , each surrounded by foil  18 , are placed in semi-cylindrical channel  134  simultaneously and arranged so that wires  16  traverse blade  136  with excess wires  16  extending, if necessary, beyond the end of contact surface  131  of blade cartridge assembly  122 . The scored jacket edge  15  of jacket  12  abuts inner wall  132 ′ of area of enlarged radius  132 . This allows an appropriate distance of eleven and one-half to fourteen millimeters of metallic foils  18  to remain on wires  16  as shown in FIG.  11 B. The absence of cable jacket  12  from semi-cylindrical channel  134  while scoring metallic foils  18  allows for unencumbered contact between blade  136  and metallic foils  18 . Tool handles  102  and  104  are then released. Tool ends  1   10  and  112  are biased together by resilient member  108  pressing blade  136  against at least one metallic foil  18 . Tool  100  is then rotated once around cable  10  to score the four individual metallic foils  18 . 
     FIGS. 11A and 11B depict the removal of scored metallic foils  18  from wires  16 . Wires  16  are bent (e.g., three times) into positions at an angle relative to cable  10  using the score in metallic foils  18  as the axis of rotation, as shown in FIG.  11 A. Wires  16  are then returned to a position in line with cable  10  and metallic foils  18  are removed by hand as depicted in FIG.  11 B. Approximately eleven and one-half to fourteen millimeters of metallic foils  18  remain wrapped on wires  16 . 
     FIGS. 12 and 13 depict the method of arranging individual wires  16  for insertion into termination caps  22  on connector  20 . Based on indicia  146 , the wires  16  are positioned in holes  144  of template cartridge assembly  142 , as shown in FIG.  12 . Wires  16  that emerge from exit holes  144 ′ are severed and discarded as shown in FIG.  13 . As noted above, the height, x, of angled extension  148  and height, y, of base  152  establish the amount of wire  16  that extends from cable jacket  12  after severing wires  16  as shown in FIG.  13 . Wires  16  are removed from template cartridge assembly  142 . Fully shielded cable  10  is now prepared for termination on insulation displacement contacts in connector  20 . 
     FIG. 14 is a perspective view of cable preparation tool  200 , an alternative embodiment of the invention. Tool  200  includes first and second tool handles  202  and  204  which are pivotally joined at a hinge  206 . Handle  202  has a tool head end  208  and handle  204  has a tool head end  210  (shown in FIG.  15 ). Tool handle  202  has a grip end  212  and handle  204  has a grip end  214 . Positioned between grip end  212  and grip end  214  is a resilient member  216  which biases tool head ends  208  and  210  towards each other as described in further detail herein. A detachable tool head  220  is mounted to handle  204  and includes a blade for scoring the jacket  12  and the foils  18  of shielded cable  10 . Handle  202  includes channels  209  that are positioned opposite channels in detachable tool head  220 . 
     Tool handle  204  includes a template  222  comprised of eight holes  224  and indicia  226  positioned adjacent to the holes. The template  222  allows the installer to arrange the wires  16  in the proper locations by positioning the wires  16  in holes  224 . The indicia adjacent to the holes  224  instruct the installer as to which wire is to be positioned in each hole  224 . Wires  16  in cable  10  are typically color coded and thus indicia  226  on template  222  may be color coded instructing the installer of the proper position for each wire  16 . Indicia  226  may also include words for indicating to the installer the type of connector the template  222  is used with (e.g. an outlet). On the inside of handles  204  and  202  are protrusions  228  and  230  each having a surface for contacting termination caps  22 . 
     FIG. 15 is an exploded, perspective view of tool  200  showing tool head  220  detached. Tool head  220  includes a semi-cylindrical first channel  240  having an end wall  242  and a semi-cylindrical second channel  244  having an end wall  246 . A blade  248  is positioned in each channel. FIG. 15 depicts the template  222  which may include indicia  226 ′ different from the indicia  226  on the opposite side of handle  204 . The indicia  226 ′ may be color codes instructing the installer of the proper position for each wire. Indicia  226 ′ may also include words for indicating to the installer the type of connector the template  222  is used with (e.g. a plug). The use of different indicia on each side of handle  204  allows a template for two different components (e.g. an outlet and a plug). 
     Use of tool  200  will now be described. FIGS. 16A and 16B depict the removal of the cable jacket  12  using tool  200 . Handles  202  and  204  are depressed towards each other as indicated by arrows A to spread tool head ends  208  and  210  apart. Cable  10  is placed in first channel  240  abutting end wall  242 . As described below with reference to FIGS. 20 and 21, the end wall  242  of channel  240  is positioned so that a predetermined amount of the jacket  12  will be removed. Handles  202  and  204  are released and spring member  216  biases tool head ends  208  and  210  towards each other. Blade  248  contacts the jacket  12 . Tool  200  is then rotated around cable  10  as shown in FIG. 16B to score the jacket  12  which then can be removed by hand. 
     FIGS. 17A and 17B depict removal of the foils  18  using tool  200 . Handles  202  and  204  are depressed towards each other as indicated by arrows A to spread tool head ends  208  and  210  apart. The four pairs of wires  16 , each surrounded by foil  18 , are placed in second channel  244  simultaneously so that the ends of wires  16  abut  246 . Second channel  244  may have a radius less than that of first channel  240 . As described below with reference to FIGS. 20 and 21, the end wall  246  of channel  244  is positioned so that a predetermined amount of the foils  18  will be removed. Handles  202  and  204  are released and spring member  216  biases tool head ends  208  and  210  towards each other. Blade  248  contacts at least one foil  18 . Tool  200  is then rotated around cable  10  as shown in FIG. 17B to score the four individual foils  18  which then can be removed by hand. 
     FIGS. 18A and 18B depicts the usage of template  222  to arrange the individual wires  16  for connector termination. Based on indicia  226  or  226 ′(depending on the installation) the wires  16  are positioned in holes  224  in template  222  to properly position wires  16  for installation with a connector. 
     FIG. 19 depicts the step of terminating the wires to a connector. Wires  16  are positioned in termination caps  22  of connector  20  in the proper order as established by template  222 . The connector  20  is positioned between handles  202  and  204  so that the termination caps  22  are positioned adjacent protrusions  228  and  230 . Handles  202  and  204  are depressed towards each other as indicated by arrows A driving the termination caps  22  into the connector  20  and terminating wires  16  on insulation displacement contacts in connector  20 . 
     FIG. 20 depicts tool head  220 . In first channel  240 , the distance from the blade  248  to the end wall  242  is equal to length A shown in FIG.  4 . As described above, to remove the jacket  12 , the cable  10  is inserted into channel  240  until the cable end contacts end wall  242 . This ensures that the right amount of jacket  12  is removed. Similarly, in channel  244  the distance between blade  248  and end wall  246  is equal to length B shown in FIG.  4 . To remove the foils  18 , the pairs of wires  16  are positioned in channel  244  until the ends of the pairs of wires  16  contact end wall  246 . This ensures that the right amount of foil is removed. 
     FIGS. 22 and 23 depict an alternative tool head  300  having a single channel  302 . It is understood that tool  200  would be modified to have a single semi-cylindrical channel aligned with channel  302  when using tool head  300 . The tool head  300  has a first side wall  308  and a second side wall  310 , as shown in FIG.  23 . Blade  304  is positioned a distance A from the first side wall  308  and positioned a distance B from the second side wall  310 . To remove the jacket  12 , the cable  10  is inserted in channel  302  from side wall  310  until the end of the cable  10  is aligned with wall  308 . The tool is then rotated to score the jacket  12  at the appropriate position. To remove the foils  18 , the cable  10  is inserted in channel  302  from side wall  308  until the ends of the pairs of wires  16  are aligned with wall  310 . The tool is then rotated to score the foils  18  at the appropriate position. Channel  302  includes an area of enlarged radius  306  (relative to the remainder of channel  302 ) that receives the cable jacket  12  when the foils  18  are being scored. The area of enlarged radius  306  allows the foils  18  to contact blade  304 . Without area  306 , the jacket  12  could prevent the foils  18  from contacting blade  304 . 
     The present invention provides a tool for removing the outer jacket, removing the foils and arranging the inner wires of fully shielded cable for termination onto a connector. The present invention reduces labor costs by reducing installation time, eliminates the need for multiple tools, and ensures the safety of the installer by eliminating the use of open blades. The invention has been described in connection with a shielded cable having four pairs of wires with each pair encased in a foil. It is understood that the invention may be adapted to use with different cable configurations such as two-pair. 
     While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.