Patent Publication Number: US-9899786-B2

Title: Coaxial cable compression tool

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This non-provisional patent application claims the benefit and priority of U.S. Provisional Patent Application No. 61/939,311, filed on Feb. 13, 2014. The entire contents of such application are hereby incorporated by reference. 
    
    
     BACKGROUND 
     The installation of coaxial cable connectors onto an end of a coaxial cable typically involves the use of specialized tools. An example of one such specialized tool is a compression device operative to secure a connector to a prepared end of the coaxial cable. An internal post is typically employed to react radial loads imposed by a connector body as the compression device causes a compression cap or a folding bellows sleeve to compress the connector body against an elastomer outer jacket of the coaxial cable. Alternatively, or additionally, such compression tools may also be used to press a barbed end of an internal post into engagement with the outer conductor and elastomer jacket to retain the cable relative to the internal post. 
     In addition to the specialized nature of such tools, the cost thereof can be sufficiently high to prohibit customers, in cost sensitive markets, from purchasing coaxial cable connectors. Additionally, the high number of component parts associated with prior art compression tools increases the cost of fabrication, maintenance and repair. At the same time, the high number of component parts reduces the reliability of such compression tools. 
     The foregoing background describes some, but not necessarily all, of the problems, disadvantages and challenges related to compression tools. 
     SUMMARY 
     A compression tool is provided, which in one embodiment includes a fixed base, a compression member and a bi-directionally pivoting handle. The fixed base includes a plunger for engaging an insert of a cable connector. The compression member slideably engages the fixed base and defines first and second cam follower surfaces. The handle pivotally mounts to the fixed base and includes first and second cam engagement surfaces engaging the first and second cam follower surfaces. The handle bi-directionally pivots about the axis to slide the compression member in one direction to facilitate loading of a connector body into a recess of the compression member, and in the other direction, to compress the connector body and the insert thereby coupling the body and the coaxial cable. 
     Additional features and advantages of the present disclosure are described in, and will be apparent from, the following Brief Description of the Drawings and Detailed Description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a broken-away isometric view of a cable which is configured to be operatively coupled to a multichannel data network. 
         FIG. 2  is a cross-sectional view of the cable, taken substantially along line  2 - 2  of  FIG. 1 . 
         FIG. 3  is a broken-away isometric view of a cable which is configured to be operatively coupled to the multichannel data network, illustrating a cable which has been spliced into a three-stepped prepared end. 
         FIG. 4  is a broken-away isometric view of a cable which is configured to be operatively coupled to the multichannel data network, illustrating a cable which has been spliced into a two-stepped prepared end. 
         FIG. 5  is a broken-away isometric view of a cable which is configured to be operatively coupled to the multichannel data network, illustrating the folded-back, braided outer conductor of the prepared cable end. 
         FIG. 6  is a broken-away perspective view of a coaxial cable connector which may be secured to the prepared end of the cable using one embodiment of the compression tool disclosed herein. 
         FIG. 7  is an isometric view of a compression tool according to one embodiment operative to couple the prepared end of the cable to a cable connector. 
         FIG. 8  is an isolated isometric view of a fixed base of the coaxial cable compression tool shown in  FIG. 7 , the fixed base including a plunger for securing an insert of the connector into a body of the connector during a working movement of the compression tool. 
         FIG. 9  is an isolated isometric view of a moveable compression member for assembly with the fixed base shown in  FIG. 8 , the moveable compression member including a recess having a U-shaped opening for urging the body toward the plunger of the fixed base to compress the connector body and secure the cable to the connector. 
         FIG. 10  is an isolated isometric view of a moveable handle for being pivotally mounted within a cradle support of the fixed base shown in  FIG. 9 , the moveable handle including a stub axle projecting from a lug structure of the cradle support. 
         FIG. 11  is an isometric view of one embodiment of the compression tool wherein the handle has been rotated to an open position to facilitate loading of the connector into the recess of the compression member. 
         FIG. 12  is an isometric view of one embodiment of the compression tool wherein the handle has been rotated into a fully compressed position to compress the insert and connector body thereby securing a prepared end of a cable in combination with a cable connector. 
     
    
    
     DETAILED DESCRIPTION 
     The compression tool shown in the illustrated embodiments is intended to couple a coaxial cable connector to a prepared end of a coaxial cable. While the cable may be constructed from a variety of materials and comprise a plurality of cross-sectional configurations, it will generally include a center or inner conductor, an outer conductor circumscribing the inner conductor, a dielectric material interposing the inner and outer conductors to provide an electrical insulator therebetween, and a compliant outer sheath disposed over the outer conductor. Similarly, the cable connectors will typically include a body disposed over and engaging the compliant outer sheath, an insert or post interposing the dielectric material and the outer conductor, and a coupler connected to the body and/or the insert for mechanically and/or electrically connecting the connector to an interface port. 
     Cable 
     In  FIGS. 1-4 , a coaxial cable  4  according to one embodiment includes: (a) an elongated center conductor or inner conductor  44 ; (b) an elongated insulator  46  coaxially surrounding the inner conductor  44 ; (c) an elongated, conductive foil layer  48  coaxially surrounding the insulator  46 ; (d) an elongated outer conductor  50  coaxially surrounding the foil layer  48 ; and (e) an elongated sheath, sleeve or jacket  52  coaxially surrounding the outer conductor  50 . 
     The inner conductor  44  is operable to carry data signals to and from the data network  5 . Depending upon the embodiment, the inner conductor  44  can be a strand, a solid wire or a hollow, tubular wire. The inner conductor  44  is, in one embodiment, constructed of a conductive material suitable for data transmission, such as a metal or alloy including copper, including, but not limited, to copper-clad aluminum (“CCA”), copper-clad steel (“CCS”) or silver-coated copper-clad steel (“SCCCS”). 
     The insulator  46 , in one embodiment, is a dielectric having a tubular shape. In one embodiment, the insulator  46  is radially compressible along a radius or radial line  54 , and the insulator  46  is axially flexible along the longitudinal axis  42 . Depending upon the embodiment, the insulator  46  can be a suitable polymer, such as polyethylene (“PE”) or a fluoropolymer, in solid or foam form. 
     In the embodiment illustrated in  FIGS. 1 and 2 , the outer conductor  50  includes a conductive RF shield or electromagnetic radiation shield. In such embodiment, the outer conductor  50  includes a conductive screen, mesh or braid or otherwise has a perforated configuration defining a matrix, grid or array of openings. In one such embodiment, the braided outer conductor  50  has an aluminum material or a suitable combination of aluminum and polyester. Depending upon the embodiment, cable  4  can include multiple, overlapping layers of braided outer conductors  50 , such as a dual-shield configuration, tri-shield configuration or quad-shield configuration. 
     In one embodiment, as described below, a cable connector electrically grounds the outer conductor  50  of the coaxial cable  4 . When the inner conductor  44  and external electronic devices generate magnetic fields, the grounded outer conductor  50  sends the excess charges to ground. In this way, the outer conductor  50  cancels all, substantially all or a suitable amount of the potentially interfering magnetic fields. Therefore, there is less, or an insignificant, disruption of the data signals running through inner conductor  44 . Also, there is less, or an insignificant, disruption of the operation of external electronic devices near the cable  4 . 
     The conductive foil layer  48 , in one embodiment, is an additional, tubular conductor which provides additional shielding of the magnetic fields. In one embodiment, the foil layer  48  includes a flexible foil tape or laminate adhered to the insulator  46 , assuming the tubular shape of the insulator  46 . The combination of the foil layer  48  and the outer conductor  50  can suitably block undesirable radiation or signal noise from leaving the cable  4 . Such combination can also suitably block undesirable radiation or signal noise from entering the cable  4 . This can result in an additional decrease in disruption of data communications through the cable  4  as well as an additional decrease in interference with external devices, such as nearby cables and components of other operating electronic devices. 
     In one embodiment, the jacket  52  has a protective characteristic, guarding the cable&#39;s internal components from damage. The jacket  52  also has an electrical insulation characteristic. In one embodiment, the jacket  52  is compressible along the radial line  54  and is flexible along the longitudinal axis  42 . The jacket  52  is constructed of a suitable, flexible material such as polyvinyl chloride (PVC) or rubber. In one embodiment, the jacket  52  has a lead-free formulation including black-colored PVC and a sunlight resistant additive or sunlight resistant chemical structure. 
     Referring to  FIGS. 3 and 4 , in one embodiment an installer or preparer prepares a terminal end  56  of the cable  4  so that it can be mechanically connected to the connector (discussed in greater detail below). To do so, the preparer removes or strips away differently sized portions of the jacket  52 , outer conductor  50 , foil  48  and insulator  46  so as to expose the side walls of the jacket  52 , outer conductor  50 , foil layer  48  and insulator  46  in a stepped or staggered fashion. In the example shown in  FIG. 5 , the prepared end  56  has a three step-shaped configuration. In the example shown in  FIG. 6 , the prepared end  58  has a two step-shaped configuration. The preparer can use cable preparation pliers or a cable stripping tool to remove such portions of the cable  4 . At this juncture, the cable  4  is ready to be connected to the connector. 
     In one embodiment illustrated in  FIG. 5 , the installer or preparer performs a folding process to prepare the cable  4  for connection to the connector. In the example illustrated, the preparer folds the braided outer conductor  50  backward onto the jacket  52 . As a result, the folded section  60  is oriented inside out. The bend or fold  62  is adjacent to the foil layer  48  as shown. In such embodiments, the folding process can facilitate the insertion of an insert or post (discussed in the subsequent section) between the braided outer conductor  50  and the foil layer  48 . 
     Connector 
     In  FIG. 6  a perspective view of a coaxial cable connector  2  shows a portion of the connector, e.g., an insert or post  70 , interposing the braided outer conductor  50 /the foil layer  48  and the dielectric core  46 . The components of the prepared cable  4 , i.e., the braided outer conductor  50 , the foil layer  48 , the dielectric core  46  and the center conductor  44  are shown in dashed or phantom lines. 
     A body  80  circumscribes an aft or barbed end portion  72  of the insert  70  while a coupler  90  circumscribes, and axially engages, a forward or flanged end portion  74  of the insert  70 . In the described embodiment, the aft end of the body  80  includes a compression cap  82  having a tapered internal surface  84  for radially engaging the aft or barbed end portion  72  of the insert  70 . When the compression cap  82  is axially displaced over the body  80 , such as by axially compressing the forward end portion  74  of the post or insert  70  toward the body  80  in the direction of arrow P (i.e., while the compression cap  82  is held in fixed by an axial force R), the tapered internal surface  84  of the body  80  is driven radially into the jacket  52  of the cable  4 . Furthermore, the jacket  52  and outer conductor  50  are driven radially toward, and against, the barbed end  72  of the insert  70 . As such, the annular barb  72  hooks the outer conductor  50  to prevent retraction of the insert  70  from the connector body  80 . 
     While the illustrated embodiment depicts a female F-type connector, i.e., the coupler  90  includes internal threads for engaging a male interface port  92 , it should be appreciated that other connectors, e.g., a male connector, may also be prepared in a similar manner. As such, a compression tool such as that described below may also facilitate preparation and engagement of a variety of other connectors. 
     Compression Tool 
     In  FIGS. 7 through 10 , a coaxial cable compression tool  100  comprises: (i) a guide frame or fixed base  102  having a static plunger  104  (see  FIG. 8 ) disposed in opposed relation to the connector  2 , (ii) a moveable slide or compression member  106  having a recess  108  for accepting a connector  2  assembled in combination with a prepared end of a coaxial cable (such as the prepared end shown in  FIG. 5 ), and (iii) a lever arm or handle  110  pivotally mounted about an axis  110 A to the fixed base  102 . The handle  110  may be bi-directionally pivoted about the axis  110 A to axially displace the compression member  106  along a line-of-action LOA, i.e., away from the pivot axis  110 A to facilitate loading of the connector within the recess  108  and toward the pivot axis  110 A such that a portion of the connector, e.g., the connector post or insert  70 , may be compressed together with a connector body  80 . 
     With respect to the latter, the line-of-action LOA is orthogonal to the pivot axis  110 A and the plunger  104  is axially opposed to a connector (i.e., when the connector  2  is loaded into the recess  108 ) such that the static plunger  104  may impart a compressive force F when the compression member  102  is drawn into or toward the static plunger  104 . As was mentioned in the preceding section, the connector body  80  is compressed by securing the connector insert  70  against the static plunger  104  and the compression cap  82  against the forward end  112  of the compression member  106 , The compressive force F drives the body  80  inwardly against the compliant outer jacket  52  and the annular barb  72  of the insert  70  as the tapered surfaces  74  of the compression cap  82  slide over the compliant terminal end of the body  80 . 
     In  FIGS. 8 and 9 , the fixed base  102  includes sidewalls  120 ,  122  which are structurally interconnected by forward, aft and intermediate cross members  124 ,  126 ,  128 . In the described embodiment, the forward and aft cross members  124 ,  126  structurally integrate the sidewalls  120 ,  122  along the lower edges or base portions thereof. The intermediate cross member  128  structurally integrates the sidewalls  120 ,  122  along an upper edge while supporting the static plunger  104  midway along the intermediate cross member  128 . The cross-members  124 ,  126 ,  128  and sidewalls  120 ,  122 , furthermore, define a space  130  for enclosing and guiding the compression member  106  along the line-of-action LOA. More specifically, the sidewalls  120 ,  122  each include a linear channel  134  defining at least one linear bearing surface  136  for accepting at least one guide rail or bearing block  138  of the compression member  106 . Additionally, or alternatively, the forward cross member  126  also defines a bearing block  144  for slideably engaging a linear bearing surface  142  formed along a linear channel  146  of the compression member  106 . The channel  146  is disposed along the underside of the compression member  106 . 
     While the cooperating channels  134 ,  146  provide linear bearing surfaces  136 , 142  to facilitate longitudinal displacement of the compression member  106  along the line-of-action LOA, the cooperating bearing surfaces and bearing blocks  134 ,  136 ,  142 ,  144  also provide lateral and vertical, i.e., side-to-side, up-and-down, retention of the compression member  106  relative to the fixed base  102 . While the guide rails  138 ,  144  and cooperating linear bearing surfaces  136 ,  142 , are formed in the compression member  106  and fixed base  102 , respectively, it should be appreciated that the guide rails  138 ,  144  and bearing surfaces  136 ,  142 , may be formed in either one of the compression member  106  and the fixed base  102 . 
     The fixed base  102  also includes a cradle support  140  for pivotally mounting the handle  110  to the base  102 . More specifically, the cradle support  140  includes a pair of lug fittings or structures  144  which are integrated with the sidewall structures  120 ,  122  of the fixed base  102 , immediately aft of the intermediate or upper cross member  128 . Furthermore, each of the lug structures  144  defines a partial cylindrical bearing surface  146  which opens to a channel  148  extending vertically from the partial bearing surface  146  to an upper portion of the respective lug structure  144 . As such, the partial bearing surface  146  inscribes an arc of at least one-hundred and eighty degrees (180°) and, in the described embodiment, the bearing surface  146  inscribes an arc which is slightly greater than one-hundred and eighty degrees (180°) to effect a snap-fit journal mount with the handle  110  (described in greater detail below). 
     As mentioned in a preceding paragraph, the compression member  106  is disposed within the space  130  provided between the cross-members  124 ,  126 ,  128  and the sidewalls  120 ,  122 , Further, the linear bearing surfaces  136 ,  142  of the fixed base  102  and compression member  106  function to guide the compression member  106  along the line-of-action LOA. The lengthwise dimension L of the recess  108 , i.e., the dimensions along the LOA, is selected to achieve a prescribed connector length, i.e., between the interface and cable connecting ends of the connector  2 . That is, the length dimension L of the recess  108  accommodates a connector of a prescribed size, such that a predetermined range of handle motion effects a known, predictable and repeatable amount of compression cycles on the body  80  of the connector  2 . 
     The recess  108  of the compression member  106  includes a U-shaped opening  150  in the forward wall  112  thereof to facilitate the passage of the prepared end of the coaxial cable  4 . Furthermore, the U-shaped opening  108  produces a shoulder  154  which abuts a peripheral edge of the connector  2  when received in the recess  108 . As such, the forward wall  112  applies the requisite compressive force on the connector body  80  when the handle  110  axially displaces the compression member  106  toward the plunger  104  of the fixed base  102 . 
     The compression member  106  also includes cam follower surfaces  150 ,  160  on each side of the handle pivot axis  110 A and, in the described embodiment, includes a forward cam follower surface  150  and an aft cam follower surface  160 . In the described embodiment the cam follower surfaces  150 ,  160  are bifurcated to form a pair of forward cam follower surfaces  152 ,  154  and a pair of aft cam follower surfaces  162 ,  164 . 
     In  FIGS. 7 and 10 , the handle  110  includes a pair of stub axles  170  (only one can be seen in  FIG. 7 ) projecting laterally from each side of the handle  110 . The stub axles  170  rotate within the partial bearing surfaces  146  of the lug structures  144  to produce a journal bearing mount for pivotally connecting the handle  110  to the fixed base  102 . As described previously, the partial bearing surfaces  146  open to vertical channels  128  which allow the stub axles  170  to slide vertically into the journal mount. The vertical channels  128  neck down in size at the transition  160  between the channel  128  and cylindrical bearing surface  146  such that the stub axles  170  are snap-fit into engagement, i.e., as the stub axles  170  pass from the channel  128  into the cylindrical bearing surface  144 . It will be appreciated that the necked-down transition  160  retains the handle  110  relative to the fixed base  102 . 
     The handle  110  rotates about the pivot axis  110 A and includes forward and aft cam engagement surfaces  176 ,  178  disposed on each side of the pivot axis  110 A. The forward and aft cam engagement surfaces  176 ,  178  of the handle  110  essentially extend from one side of the handle  110  to the opposite side. Rotation of the handle  110  in a clockwise direction CL causes the forward cam engagement surfaces  176  to engage the forward cam follower surfaces  152 ,  154  to displace the moveable compression member  106  forwardly to an open position. Rotation of the handle  110  in a counter-clockwise direction CC causes the aft cam engagement surfaces  178  to engage the aft cam follower surfaces  162 ,  164  to displace the moveable compression member  106  rearwardly to a fully compressed position. 
     In operation, and referring to  FIGS. 11 and 12 , the handle  110  is initially rotated in a clockwise direction CL to a substantially vertical position ( FIG. 11 ). Furthermore, when the handle  110  is vertical, the front wall  112  of the moveable compression member  106  is brought forward of the fixed base  102 . In this open position, the recess  108  is fully-accessible to accept a cable connector. Upon preparation of a connector, an installer places the connector  2  into the recess  108  such that an open end  190  of the connector  2  faces the static plunger  104 . Inasmuch as the installer may physically place the insert  70  between the dielectric core  46  and the braided outer conductor  50 , the insert  70  may partially protrude beyond the connector body  80 . 
     Rotation of the handle  110  in a counter-clockwise direction CC causes the forward cam engagement surface  176  of the handle  110  to urge the moveable compression member  106  rearwardly toward the static plunger  104 . As a portion of the connector  2  comes into contact with the static plunger  104 , the installer continues to rotate the handle  110  downwardly to a horizontal position to fully compress the connector  2  against the static plunger  104 . When the handle  110  has been fully rotated, the moveable compression member  106  is in its fully compressed position. In this position, the compression cap  82  may be urged forwardly onto the body  80  such that the tapered internal surface  84  of the compression cap  82  radially displaces the body  80  against the barbed end  72  of the insert  70 . As such, the barbed end  72  prevents the insert  70  from backing away from, or out of, the connector body  80 . Thereafter, the moveable compression member  106  returns to a ready position, i.e., the open position, by rotating the handle  110  in a clockwise direction CL. 
     While the connector  2  depicted employs a conventional compression cap  82  to secure the prepared end of the cable  4  to the connector  2 , other connector configurations may be used in conjunction with the compression tool  100 . For example, a connector may employ a bellows structure (not shown) to fold into and engage an outer periphery of the coaxial cable  4 , i.e., the elastomeric jacket  52 . In some connectors the post is driven deeply into the body and in others the stroke of the insert or post is relatively short. Furthermore, to accommodate different size connectors, the static plunger  104  may threadably engage an internal post (not shown), to vary the accessible length or size of the recess  108 . 
     The compression tool  100  excludes pins, screws, bolts and similar fasteners. The moveable compression member  106  fits into the fixed base  102  without any fasteners. The handle  110  is connected to the base  102  though a snap-fit connection without any fasteners. Specifically, the stub axles  170  of the handle snap into the bearing surfaces  172 ,  174  of the base. In one embodiment, the compression tool has a fastener-free configuration with three parts, a unitary fixed base  102  (having a static plunger  104  integral with the fixed base  102 ), a unitary compression member  106  and a unitary handle  110 . 
     The compression tool  100  may be fabricated using relatively low cost molding techniques. For example, each of the three components, i.e., the fixed base  102 , moveable compression member  106 , and handle  110  may be injection molded using a relatively low friction thermoplastic polymer. Since the components are fabricated from a self-lubricating thermoplastic, frictional wear and abrasion between mating components is minimized. That is, there is no need to lubricate the moving components. Finally, since the compression tool  100  may be fabricated from as few as three components, the low number of component parts improves the reliability and lowers the cost of the compression tool  100 . 
     Additional embodiments include any one of the embodiments described above, where one or more of its components, functionalities or structures is interchanged with, replaced by or augmented by one or more of the components, functionalities or structures of a different embodiment described above. 
     It should be understood that various changes and modifications to the embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present disclosure and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims. 
     Although several embodiments of the disclosure have been disclosed in the foregoing specification, it is understood by those skilled in the art that many modifications and other embodiments of the disclosure will come to mind to which the disclosure pertains, having the benefit of the teaching presented in the foregoing description and associated drawings. It is thus understood that the disclosure is not limited to the specific embodiments disclosed herein above, and that many modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although specific terms are employed herein, as well as in the claims which follow, they are used only in a generic and descriptive sense, and not for the purposes of limiting the present disclosure, nor the claims which follow.