Abstract:
The present disclosure provides a device and related method for securing cables as they are stripped and connectorized or otherwise processed. The device  10  is designed to quickly and efficiently secure an exterior portion of a cable by clamping onto the cable with a predetermined amount of force so as to not cause damage to the cable. The device  10  is also optimized for quick and efficient insertion and retraction of the cable from the device  10.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to U.S. Provisional Application Ser. No. 62/092,195, filed on Dec. 15, 2014, entitled SELF-CENTERING OPTICAL FIBER CLAMP, the disclosure of which is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND 
       [0002]    Devices have been developed to secure optical and electrical cables in place while they are stripped and connectorized. Improved devices that are easy to operate, reliable, and do not damage the cables are desirable. 
       SUMMARY 
       [0003]    The present disclosure provides a device and related method for securing cables as they are stripped and connectorized or otherwise processed. The device is designed to quickly and efficiently secure an exterior portion of a cable by clamping onto the cable with a predetermined amount of force so as to not cause damage to the cable yet hold the cable securely. The device is also optimized for quick and efficient insertion and retraction of the cable from the device. 
         [0004]    A multi-clamp device to fix and center an optical fiber is provided in one embodiment. The clamps enclose the fiber buffer without gaps, which makes it possible to use higher pressure without damaging the internal fiber cladding. The high clamping force is desired to prevent axial slipping of the glass through the buffer during stripping or cleaving of the optical fiber. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a rear perspective view of a cable clamp assembly according to principles of the present disclosure; 
           [0006]      FIG. 2  is a front perspective of the cable clamp assembly of  FIG. 1 ; 
           [0007]      FIG. 3  is a front exploded view of the cable clamp assembly of  FIG. 1 ; 
           [0008]      FIG. 3A  is an enlarged portion of  FIG. 3 ; 
           [0009]      FIG. 3B  is an enlarged portion of  FIG. 3 ; 
           [0010]      FIG. 3C  is an enlarged portion of  FIG. 3 ; 
           [0011]      FIG. 4  is a front partially exploded view of the cable clamp assembly of  FIG. 1 ; 
           [0012]      FIG. 5  is a rear partially exploded view of the cable clamp assembly of  FIG. 1 ; 
           [0013]      FIG. 6  is a rear view of the cable clamp assembly in a first state; 
           [0014]      FIG. 7  is a rear view of the cable clamp assembly in a second state; 
           [0015]      FIG. 8  is a rear view of the cable clamp assembly in a third state; 
           [0016]      FIG. 9  is a front view of the cable clamp assembly in the first state; 
           [0017]      FIG. 10  is a front view of the cable clamp assembly in the second state; 
           [0018]      FIG. 11  is a front view of the cable clamp assembly in the third state; 
           [0019]      FIG. 12  is a rear view of the cable clamp assembly in the first state with portions removed; 
           [0020]      FIG. 13  is a rear view of the cable clamp assembly in the second state with portions removed; 
           [0021]      FIG. 14  is a rear view of the cable clamp assembly in the third state with portions removed; 
           [0022]      FIG. 15  is a cross-sectional view along  15 - 15  in  FIG. 8 ; 
           [0023]      FIG. 16  is an elevation view of a portion of the fixed body component of the cable clamp assembly of  FIG. 1 ; 
           [0024]      FIG. 17  is an elevation view of a portion of the cable engagement assembly of the cable clamp assembly of  FIG. 1 ; 
           [0025]      FIG. 18  is an elevation view of a portion of the rotating body component of the cable clamp assembly of  FIG. 1 ; 
           [0026]      FIG. 19  is an elevation view of a portion of the force limiting radial drive assembly of the cable clamp assembly of  FIG. 1 ; and 
           [0027]      FIG. 20A  is a rear view of an alternative embodiment of the cable clamp assembly in a first state; 
           [0028]      FIG. 20B  is a rear view of the cable clamp assembly of  FIG. 20A  in the first state with certain portions removed; 
           [0029]      FIG. 20C  is a rear view of the cable clamp assembly of  FIG. 20A  in the first state with additional portions removed relative to  FIG. 20B ; 
           [0030]      FIG. 20D  is a rear perspective view of the cable clamp assembly of  FIG. 20A  in the first state; 
           [0031]      FIG. 21A  is a rear view of an alternative embodiment of the cable clamp assembly in a second state; 
           [0032]      FIG. 21B  is a rear view of the cable clamp assembly of  FIG. 21A  in the second state with certain portions removed; 
           [0033]      FIG. 21C  is a rear view of the cable clamp assembly of  FIG. 21A  in the second state with additional portions removed relative to  FIG. 21B ; 
           [0034]      FIG. 21D  is a rear perspective view of the cable clamp assembly of  FIG. 21A  in the second state; 
           [0035]      FIG. 22A  is a rear view of an alternative embodiment of the cable clamp assembly in a third state; 
           [0036]      FIG. 22B  is a rear view of the cable clamp assembly of  FIG. 22A  in the third state with certain portions removed; 
           [0037]      FIG. 22C  is a rear view of the cable clamp assembly of  FIG. 22A  in the third state with additional portions removed relative to  FIG. 22B ; and 
           [0038]      FIG. 22D  is a rear perspective view of the cable clamp assembly of  FIG. 22A  in the third state. 
       
    
    
     DETAILED DESCRIPTION 
       [0039]    Referring to  FIGS. 1-19 , an embodiment of a cable clamping assembly according to the present disclosure is described below. In the depicted embodiment, the cable clamping assembly  10  can be a stand-alone device or, alternatively, it can be a module in a larger cable processing system that includes other modules. For example, the cable clamp assembly of the present disclosure could be axially aligned with a cable stripping module, a module that connectorizes the cable strands, overmolding modules, or any number of other modules to form part of a larger system. 
         [0040]    When an optical fiber end has to be stripped or cleaved, for example, an axial force is exerted between the fiber buffer and the fiber glass. Therefore, it is necessary to clamp the fiber buffer during this process. In many cases it is detrimental if the fiber glass slips inside the fiber buffer while in the clamp. Slipping can be especially problematic with the semi-tight fibers. If clamping is done between two flat clamps, when the clamping force is increased, the buffer can be cut and the glass can be damaged. The present disclosure includes multiple clamps, such as four clamps, that form a closed clamping area. These clamps can move in and out relative to each other such that there is no gap between them. This coordinated movement performs a self-centering function and will support easy fiber infeed, and therefore it is possible to apply a very high pressure on the fiber buffer without damaging the glass inside. 
         [0041]    In the depicted embodiment, the cable clamping assembly  10  of the present disclosure includes a number of subassemblies. Referring particularly to  FIG. 3 , the cable clamping assembly  10  includes a cable engagement assembly  12  configured to selectively apply pressure to an exterior section of a cable. The cable clamping assembly  10  includes a force limiting radial drive assembly  28  configured to radially drive the clamp arms  14 ,  16 ,  18 ,  20  and limit the force that the clamp arms  14 ,  16 ,  18 ,  20  apply onto the cable. The cable clamping assembly  10  includes a drive assembly  50  configured to transmit rotational movement from a drive shaft into radial movement of the cable engagement assembly  12 . In addition, the cable clamping assembly  10  of the depicted embodiment includes a cable guide assembly  52  that facilitates guiding of the cable into and out of the cable clamping assembly. Each of these subassemblies will be described in greater detail below. It should be appreciated that alternative embodiments of the present disclosure may include more, fewer or different subassemblies. 
         [0042]    In the depicted embodiment, the cable engagement assembly  12  includes a plurality of cable clamp arms  14 ,  16 ,  18 ,  20  arranged to surround a cable and simultaneously move towards a cable applying balanced forces to the exterior section of the cable. In the depicted embodiment, the cable engagement assembly  12  includes four cable clamp arms  14 ,  16 ,  18 ,  20  that cooperatively completely surround the cable. In the depicted embodiment, each of the four clamp arms shares the same features. As such, only one of the clamp arms will be described in greater detail herein. However, it should be appreciated that in alterative embodiments the cable engagement assembly could have more or fewer clamp arms and not all of the clamp arms need necessarily share the same structural features (i.e., the clamp arms can be different). 
         [0043]    In the depicted embodiment, the clamp arm  14  includes a main body that defines a widened curved cable engagement surface  22 . The cable engagement surface  22  has a width W 1 . In the depicted embodiment, the width of the body at an opposed edge is W 2 , and W 1  is greater than W 2  by 150 to 500 percent. In the depicted embodiment, the widened portion  42  of the clamp arm is formed of the same material as the main body portion. The widened portion  42  could be, for example, formed integral with the main body portion via an injection molding or machining process or, alternatively, formed separately and later connected to the main body of the clamp arm  14 . This widened construction of the curved cable engagement surface  22  allows for more even distribution of force onto the cable and results in greater friction hold between the clamp arms and the cable while avoiding damage to the cable. In the depicted embodiment, the clamp arm  14  includes a beveled edge  48  at the junction between the rear face and curved cable engagement surface  22  and a scalloped lead in at the junction between the front face and the curved cable engagement surface  22 . These features further minimize the risk of damage to the cable due to the engagement of the cable clamp arm  14  with the cable. It should be appreciated that many alternative clamp arm configurations are possible. For example, it should be appreciated that in alternative embodiments the clamp arms themselves may be constructed of more than one material and can be shaped differently than depicted herein. 
         [0044]    In the depicted embodiment, the clamp arm  14  includes a clamp arm pivot  24  that pivotally connects the clamp arm  14  to a fixed body  38 . In the depicted embodiment, the clamp arm pivot  24  is a boss that is inserted into an aperture  44  in the fixed body  38 . It should be appreciated that many alterative configurations are possible including, for example, the pivot being an aperture on the clamp arm  14  that receives a boss that extends from the fixed body  38 . 
         [0045]    In the depicted embodiment, the clamp arm  14  includes a wheel  26  on a rear face that is configured to rotatably engage a channel  32  in a guide plate  46 . Generally when the guide plate  46  moves relative to the clamp arm  14 , the clamp arm  14  pivots about the clamp arm pivot  24  thereby causing radial displacement of the curved cable engagement surface  22 . The construction and function of the guide plate  46  will be described in further detail as part of the description of the clamp arm drive assembly  28 . As will be explained below, once a certain amount of force has been applied to the cable via the clamp arms, the guide plate  46  will pivot radially outward instead of causing radial inward displacement of the curved cable engagement surface  22 . 
         [0046]    In the depicted embodiment, the curved cable engagement surface  22  includes a curvature that facilitates smooth synchronized motion between the plurality of clamp arms  14 ,  16 ,  18 ,  20 . In the depicted embodiment, portions of the curved cable engagement surface  22  include a radius of curvature that corresponds to half the distance between opposed clamp arm pivots  24 . In the depicted embodiment, the curved cable engagement surface  22  includes a constant radius of curvature. It should be appreciated that many alternative configurations are also possible. 
         [0047]    As discussed above, the cable clamping assembly  10  includes a force limiting radial drive assembly  28  configured to radially drive the clamp arms and limit the force that the clamp arms apply onto the cable. The cable clamp arm drive assembly  28  will be discussed in further detail below. In the depicted embodiment, the cable clamp drive assembly  28  includes a plurality of guide plates  46 . In the depicted embodiment, the clamp arm drive assembly  28  includes four guide plates  46 . Each of the guide plates correspond to a different clamp arm and share the same features and functions. 
         [0048]    Accordingly, only a single guide plate  46  will be described in further detail herein. It should be appreciated that alternative embodiments may not include guide plates or may include fewer or more guide plates. 
         [0049]    In the depicted embodiment, the guide plate  46  includes a channel  32  configured to engage the wheel  26  of the cable clamp arm  14 . As the guide plate  46  moves, the wheel  26  rolls in the channel and causes the clamp arm  14  to pivot about the clamp arm pivot  24 . The pivoting of the clamp arm  14  results in radial displacement of the curved cable engagement surface  22 . In the depicted embodiment, the channel  32  of the guide plate  46  includes a non-uniform profile including a first portion having a first curved shaped configured to drive the clamp arm radially at a first speed, and a second portion having a shape configured to drive the clamp arm radially at a second speed, the second speed being slower than the first speed. In the depicted embodiment, the transition is set based on when it is expected that the cable clamp  14  initially would contact the cable. 
         [0050]    In the depicted embodiment, the guide plate  46  includes a guide plate pivot  34 , which is pivotally connected to a guide plate support arm  36 . The guide plate support arm  36  is connected to the rotating body  40 . As the rotating body rotates, the guide plate support arm  36  moves with the rotating body  40 , which causes the guide plate  46  to move. The movement of the guide plate, as discussed above, drives the radial displacement of the curved cable engagement surface  22  of the cable clamp arm  14 . 
         [0051]    In the depicted embodiment, a clamp force limiting device  30  is connected between the rotating body  40  and the guide plate  46 . The clamp force limiting device is configured to limit the amount of force that can be applied to the cable to prevent damage to the cable. In the depicted embodiment, the clamp force limiting device functions while allowing a full range of motion of the drive assembly. 
         [0052]    In the depicted embodiment, the clamp force limiting device is a coil spring with a known preload. In the depicted embodiment, once the cable clamp arm  14  imparts a predetermined amount of force on the cable, the cable clamp arm  14  stops displacing towards the cable, thereby limiting the amount of force that is imparted onto the cable. The displacement stops even as the rotating body  40  continues to rotate. 
         [0053]    As discussed above, the cable clamping assembly  10  includes a drive assembly  50  configured to transmit rotational movement from a drive shaft into radial movement of the cable engagement assembly  12 . The drive assembly  50  will be discussed in further detail below. In the depicted embodiment, the drive assembly  50  includes a fixed body  38  and a rotating body  40 . In the depicted embodiment, a bearing assembly  56  interfaces between the fix body  38  and rotating body  40  to facilitate relative rotation therebetween. 
         [0054]    In the depicted embodiment, the fix body  38  can include multiple parts that are connected together to form a structure that is stationary. In the depicted embodiment, the fixed body  38  includes a portion that is pivotally connected to the clamp arm pivot  24 . In the depicted embodiment, the rotating body  40  of the drive assembly  50  is configured to rotate relative to the fixed body  38 . In the depicted embodiment, the guide plate support arm  36  is connected to the rotating body  40  and supports the guide plate  46  thereon. In the depicted embodiment, the rotating body  40  includes a number of structural components connected to each other. In the depicted embodiment, the periphery portion of the rotating body  40  includes a ring gear  58  for driving the rotation thereof and the drive assembly also includes a drive gear  84  supported on the fixed body  38  that is configured to cause the rotation of the ring gear  58  of the rotating body  40 . 
         [0055]    The cable clamping assembly  10  of the depicted embodiment also includes a cable guide assembly  52 . The cable guide assembly  52  is configured to facilitate the insertion of a cable into the cable clamping assembly  12 . The cable guide assembly expands to allow the cable to be easily removed. This is especially advantageous when the end of the cable has been connectorized and has a much greater cross-sectional area than the cable itself. In the depicted embodiment, the cable guide assembly has a tapered funnel shape and includes a first portion  62  and a second portion  64 . The first portion  62  is configured to move away from the second portion  64  against a spring force as the cable clamps are retracted to allow for the easy retraction of the end of the cable from the cable clamp assembly  10 . 
         [0056]    The present disclosure also provides a method of clamping a cable. In one embodiment of the method, the method includes the steps of axially feeding an end of a cable through a funnel shaped cable guide assembly  52  and through a plurality of clamp arms  14 ,  16 ,  18 ,  20 , wherein the clamp arms are co-planar and completely surround the cable. The method includes the step of radially driving the plurality of clamp arms  14 ,  16 ,  18 ,  20  towards the cable in a synchronized first rate and radially driving the plurality of clamp arms towards the cable in a synchronized second rate after the first rate, wherein the second rate is slower than the first rate. The method includes the step of stopping the radial movement once a predetermined amount of force is applied to the exterior of the cable by the clamp arms. In the depicted embodiment, the step of radially driving the plurality of clamp arms towards the cable in a synchronized first rate and radially driving the plurality of clamp arms towards the cable in a synchronized second rate, as well as the step of stopping the radially movement once a predetermined amount of force is applied to the exterior of the cable by the clamp arms, occurs without changing the output shaft  66  speed or toque on a motor  60  that drives the plurality of cable clamps  14 ,  16 ,  18 ,  20 . 
         [0057]    In the depicted embodiment, the first rate is based on the shape of a first aperture  68  in the guide plate  46 , and the second rate is based on the shape of a second aperture  70  in the guide plate. In the depicted embodiment, the radial movement is stopped once a spring is compressed with a predetermined amount of force. This stopping prevents damage to the cable yet avoids the need to precisely control the motor and/or provide the motor controller with feedback regarding the force applied to the cable. 
         [0058]    In some embodiments of the method, the method also includes the step of connecting a connector to the end of the cable (i.e., connectorizing the cable). In such embodiments, the connector may have a cross-sectional area that is greater than 150 percent of the cross-sectional area of the cable (e.g., 1.5-10 times the cross-sectional area of the cable). To allow for easy removal of the relatively large connectorized cable end, the method includes the step of automatically separating the funnel shaped guide to allow for easily retracting the end of the cable. In the depicted embodiment, the clamp arm  14  includes a first boss  72  that extends forward that selectively engages first flange  76  on the first body portion  62  of the cable guide assembly  52 . Likewise, the clamp arm  18  includes a second boss  74  that extends forward that selectively engages second flange  78  on the second body portion  64  of the cable guide assembly  52 . Once the clamp arm  14  rotates a set amount in the opening direction, the first boss  72  drives against the first flange  76  causing the first body portion  62  to pivot about the first pivot  80 . Similarly, once clamp arm  18  rotates a set amount in the opening direction, the second boss  74  is driven against the second flange  78  resulting in the rotation of the second body portion  64  about the second pivot. Consequently, the rotation of the cable clamp arms  14 ,  18  in an opening direction drives the first body portion  62  and second body portion  64  to separate. See  FIGS. 12-14 . In the depicted embodiment the body portions of the funnel shaped guide are spring biased towards a closed position. It should be appreciated that many other alternative configurations are also possible. 
         [0059]      FIGS. 20-22  show an alternative cable clamp assembly, with rotating clamp arms, and a wheel and slot arrangement for moving the clamp arms.  FIGS. 20A-D  show the cable clamp assembly in a first position.  FIGS. 21A-D  show the cable clamp assembly in a second position.  FIGS. 22A-D  show the cable clamp assembly in a third position. 
         [0060]    The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended. 
       PARTS LIST 
       [0000]    
       
           10  cable clamping assembly 
           12  cable engagement assembly 
           14  cable clamp arm 
           16  cable clamp arm 
           18  cable clamp arm 
           20  cable clamp arm 
           22  curved cable engagement surface of clamp arm 
           24  clamp arm pivot 
           26  wheel on clamp arm 
           28  force limiting radial drive assembly 
           30  clamp force limiting device 
           32  channel in guide plate 
           34  guide plate pivot 
           36  guide plate support arm 
           38  fixed body 
           40  rotating body 
           42  widened portion of clamp arm 
           44  aperture in the fixed body 
           46  guide plate 
           48  beveled edge 
           50  drive assembly 
           52  cable guide assembly 
           54  scallop on cable clamp arm 
           56  bearing assembly 
           58  ring gear 
           60  motor 
           62  first portion of the cable guide assembly 
           64  second portion of the cable guide assembly 
           66  output shaft 
           68  first aperture 
           70  second aperture 
           72  first boss 
           74  second boss 
           76  first flange 
           78  second flange 
           80  first pivot 
           82  second pivot 
           84  drive gear