Abstract:
A device is disclosed for stripping an outer material from a transmission carrier that has an end block defining a passageway therethrough for positioning the transmission carrier therein. Grip members are pivotally attached to the end block and movable between an open position and a cutting position. In one embodiment, an alignment mechanism is attached to at least one of the grip members for holding the outer material of the transmission carrier at a distal point spaced from the end block with a predetermined alignment and/or clamping force to inhibit buckling of the outer material during removal. A cutting mechanism associated with the end block proximate to the passageway is actuated by pivoting the grip members to a cutting position for removal of the outer material. Another variation includes a fracture mechanism that induces material fracture of the outer material during pivoting of the grip members.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates generally to a stripping device having one or more alignment maintaining features. More particularly, the present invention relates to a device for readily stripping protective material from electrical wiring and/or fiber optic strands where alignment is maintained so as to allow for stripping longer lengths of material more accurately and reliably.  
       BACKGROUND OF THE INVENTION  
       [0002]     Fiber optic strands generally have various outer layers around their optical fibers, such as coating or buffering layers or outer jackets. Electrical wires also generally have some sort of outer insulation or jacket. When such strands or wires are connected, it is common to strip the outer layers as part of the termination process.  
         [0003]     Various devices have been proposed for use in stripping of protective outer materials from fiber optic strands and electrical wires (collectively referred to as “transmission carriers” below). For example, U.S. Pat. No. 4,271,729 discloses such a device in which two grip members are pivotably attached to an end block. Movable blade members are mounted in the end block. The wire to be stripped is slid through an opening in the end block, and then the grip members are squeezed together, thereby bringing the blade members together to cut into the protective material to be stripped. The wire is then pulled through the device and out of the end block, sliding the wire&#39;s metal carrier out of the protective coating “downstream” of the blade members, thereby stripping the inserted wire. U.S. Pat. No. 4,850,108 discloses a related stripping device suitable for stripping an array of fiber optic strands. MICRO-STRIP® tools from Micro Electronics, Inc. are further examples of available stripping tools.  
         [0004]     While currently available devices work well in many applications, in particular in stripping relatively shorter lengths of material on the order of a few centimeters, further improvement is possible. For example, if longer lengths of material are to be stripped, the protective material on the loose downstream end may bind, bend, and/or buckle, resulting in an inaccurate or incomplete stripping. Also, with currently available tools, technicians may have to strip longer lengths in several steps (i.e., 5 centimeters at a time in three steps to strip 15 centimeters). Along with being time consuming, such repeated stripping and resultant handling of an optical fiber transmission carrier increases the possibility of inadvertent damage. Even for relatively shorter lengths, available devices do not positively maintain fiber alignment or securely hold the protective material during stripping, which can lead to imperfect results at times. These issues are magnified when attempting to strip relatively long lengths and/or small diameter optical fibers. Therefore, gripping and/or alignment of the transmission carrier to be stripped could be improved, particularly for longer strip lengths and/or smaller diameter transmission carriers, thereby providing a more effective and reliable tool.  
       SUMMARY OF THE INVENTION  
       [0005]     A device is disclosed for stripping an outer material from a transmission carrier, the device includes an end block defining a passageway therethrough, the transmission carrier being placeable in the passageway. A pair of grip members is pivotally attached to the end block and movable between an open position and a scoring or cutting position. In one embodiment, an alignment mechanism is attached to at least one of the grip members for holding the transmission carrier at a distal point spaced from the end block with a predetermined clamping force. A scoring or cutting mechanism is attached to the end block proximate the passageway and actuated by pivoting of the grip members to the cutting position to cut into the outer material of the transmission carrier. The transmission carrier can be removed from the passageway while the alignment mechanism holds the end portion of the outer material of the transmission carrier at the distal point, thereby allowing a stripping off the end portion while inhibiting bending, binding and/or buckling over a length of the end portion. Various options and modifications of the concepts of the present invention are possible.  
         [0006]     For example, the device may further include a spring member attached to at least one of the grip members for biasing the grip members to an open position. The alignment mechanism may include a resilient clamping member for providing the predetermined clamping force at a distal point from the end block or generally along or at a distance from the end block. The predetermined clamping force should not provide a crushing force that can damage the transmission carrier. However, the alignment mechanism should apply a sufficient pulling force for removing the end portion of the outer material being stripped. In another embodiment, the alignment mechanism can provide a pulling force, thereby initiating a separation of the covering being removed.  
         [0007]     Further, the grip members may include heel portions and toe portions extending from the heel portions, the grip members being pivotally attached to the end block via the heel portions, and the alignment mechanism may include at least one resilient clamping member being attached to the toe portions. If so, the toe portions may contact each other, and the at least one resilient clamping member may be compressed when the grip members are in the cutting position. The grip members may include heel portions and toe portions extending from the heel portions, and the alignment mechanism may include a notch disposed in a surface of at least one of the toe portions, thereby inhibiting the formation of a crushing zone between the grip members. Also, the grip members may include heel portions and toe portions extending from the heel portions, and the alignment mechanism may include a first alignment mechanism disposed on at least one of the toe portions, and further including a second alignment mechanism disposed between the cutting mechanism and the first alignment mechanism. If so, the first alignment mechanism may include one or more of at least one flexible member and a notch disposed in at least one of the toe portions.  
         [0008]     The cutting mechanism may include two reciprocating cutting blades, and the two reciprocating cutting blades may be held in the end block such that they are removable and replaceable. Likewise, the end block may further include a removable and replaceable transmission carrier insert guide for positioning and inserting the transmission carrier relative to the cutting mechanism.  
         [0009]     In further variations, a relief passage is disposed in at least one of the grip member toe portions sized for receiving the end portion of the outer material when the grip members are in the cutting position. As above, various options and modifications are possible.  
         [0010]     Preferably, a resilient means is provided for holding a portion of the outer material at a distal point spaced from the cutting mechanism with a force sufficient to allow the end portion of the outer material to be stripped from the transmission carrier, thereby inhibiting buckling over a portion of the outer material being stripped. As above, various options and modifications are possible. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES  
       [0011]      FIG. 1  is a top perspective view of one embodiment of a stripping device according to certain aspects of the present invention.  
         [0012]      FIG. 2  is a side view of the device of  FIG. 1 .  
         [0013]      FIG. 3A  is a cross-sectional view of the device of  FIG. 1  taken along lines  3 A- 3 A in  FIG. 2 .  
         [0014]      FIG. 3B  is a cross-sectional view of the device as in  FIG. 3A  showing insertion of a transmission carrier to be stripped.  
         [0015]      FIG. 3C  is a close-up cross-sectional view of an end of the stripping device as in  FIG. 3A  showing grip members in an open position.  
         [0016]      FIG. 3D  is a cross-sectional view of the stripping device as in  FIG. 3A  showing the grip members in a closed position, thereby at least partially cutting the outer material of the transmission carrier and clamping an end portion being removed.  
         [0017]      FIG. 3E  is a close-up cross-sectional view of the stripping device as in  3 D.  
         [0018]      FIG. 3F  is a cross-sectional view of the stripping device showing removal of the stripped transmission carrier from the stripping device while the end portion of outer material is retained.  
         [0019]      FIG. 4  is a close-up cross-sectional view of the toe end of the stripping device as in  FIG. 3D .  
         [0020]      FIG. 5  is a cross-sectional view of the stripping device taken along lines  5 - 5  in  FIG. 4  showing one embodiment of a relief passage.  
         [0021]      FIG. 6  is a cross-sectional view of the stripping device taken along lines  6 - 6  in  FIG. 5  showing one embodiment of a clamping member.  
         [0022]      FIG. 7  is a side view of an alternate stripping device according to certain other embodiments of the invention.  
         [0023]      FIG. 8  is a diagrammatical representation of an alternate alignment mechanism for a stripping device according to the invention.  
         [0024]      FIG. 9  is a diagrammatical representation depicting another alternate design of an alignment mechanism according to the invention.  
         [0025]      FIGS. 10   a - 10   c  depict different blade configurations that can be used with the concepts of the stripping device. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0026]     Detailed reference will now be made to the drawings in which examples embodying the present invention are shown. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention.  
         [0027]     The drawings and detailed description provide a full and written description of the invention, and of the manner and process of making and using it, so as to enable one skilled in the pertinent art to make and use it, as well as the best mode of carrying out the invention. However, the examples set forth in the drawings and detailed description are provided by way of explanation of the invention and are not meant as limitations of the invention. The present invention thus includes any modifications and variations of the following examples as come within the scope of the appended claims and their equivalents.  
         [0028]     Described below are multiple embodiments and modifications to designs of stripping devices useful for stripping relatively long lengths of protective material from transmission carriers such as fiber optic strands and electrical wires. The concepts of the present invention generally inhibit bending, binding, and/or buckling (hereinafter buckling) of the portion of the transmission carrier being stripped, thereby allowing improved performance. The disclosed devices can be modified for use with other transmission carriers and/or varying sizes of transmission carriers. For example, fiber optic strands may have outer coating with outer diameters in the range of 200 microns or less, and may range up to 900 microns or more that require stripping for termination. The individual optical fibers disposed within the coatings have smaller diameters. Further, the concepts of the invention may be used with coated fibers having polymeric or UV curable coatings or outer jackets with varying dimensions. The disclosed designs also have applicability to stripping electrical wire of varying sizes. Accordingly, it should be understood that the disclosed designs may be used with many different types of transmission carriers, and the specific examples disclosed herein should not be considered limiting.  
         [0029]      FIGS. 1-6  show a first example of a stripping device  10  according to certain aspects of the present invention. As shown, stripping device  10  includes grip members  12  and  14  pivotally mounted to an end block  16 . A scoring or cutting mechanism  18  (hereinafter cutting mechanism) is disposed within end block  16  and is actuated by a pivoting of grip members  12  and  14 . As discussed below, various mechanisms may be employed to hold a coated and/or jacketed transmission carrier  20  to allow stripping of an end portion  22  of outer material from the transmission carrier by inhibiting buckling of the transmission carrier during use of the device. As best shown by  FIGS. 5 and 6 , coated transmission carrier  20  includes a transmission carrier  20   a  that carries the signal and an outer material such as a coating or jacket (not numbered) that protects transmission carrier  20   a .  
         [0030]     As shown in  FIG. 3A , grip members  12  and  14  each include heel ends  24  and  26  pivotally disposed within cavities  28  and  30  formed in end block  16 . A spring member  32  may be attached to at least one of grip members  12  and  14  to urge grip members toward the open position, as shown in  FIG. 3A . Spring member  32  as shown comprises a dual leaf-spring member having two ends  34  and  36  attached to pins  38  and  40  formed on grip members  12  and  14 .  
         [0031]     As best shown in  FIGS. 3C and 3E , cutting mechanism  18  includes two movable cutting blades  42  and  44  carried by carriers  46  and  48  disposed within end block  16 . Ends  50  and  52  of carriers  46  and  48  are located within recesses  54  and  56  formed within grip members  12  and  14 . Movement of grip members  14  and  16  from the position shown in  FIG. 3A  to the position shown in  FIG. 3D  causes blades  42  and  44  to come together (see close-up views in  FIGS. 3C and 3E ) to cut into the outer material  20   b , thereby creating the end portion  22  for removal. In this embodiment, blades  42  and  44  are sized with an aperture therebetween for a given transmission carrier as shown in  FIG. 10   a  for merely scoring the outer material, thereby inhibiting damage to the same. Additionally, spring member  32  biases blades  42  and  44  toward the open position, shown in  FIG. 3C , and compressing grip members  12  and  14  together moves the blades to the cutting position shown in  FIG. 3E .  
         [0032]     A transmission carrier insert guide  58  may be attached to end block  16  to guide the transmission carrier through the end block and past cutting mechanism  18 . Transmission carrier insert guide  58  may be a removable and replaceable part sized for a particular diameter, shape, and/or size of the transmission carrier. Accordingly, a family of such transmission carrier insert guides may be provided for a given stripping device so that various sizes of transmission carriers may be accurately stripped using stripping device  10 . Likewise, blades  42  and  44  can be removed and accordingly sized for a particular transmission carrier geometry. Transmission carrier insert guide  58  may include a body portion  60 , an outer flange  62 , and a neck section  64  sized to receive the particular transmission carrier to be stripped. A removable guide lock  66  may be used to hold the selected transmission carrier insert guide  58  in place within end block  16 .  
         [0033]     As mentioned above, various forms of an alignment mechanism may be employed to ensure transmission carrier  20  is held and may be stripped without buckling. For example, as shown in  FIG. 1 , at least one resilient clamping member  70  may be attached to a grip member  12 . If desired, a second resilient clamping member  72  may be attached to the other grip member  14 . Resilient clamping members  70  and  72  may be-formed of a foam material or other suitable compliant material. As shown in  FIGS. 3D and 4 , when grip members  12  and  14  are brought together so as to move cutting mechanism  18  into the cutting position, resilient clamping members  70  and  72  are compressed together to thereby hold transmission carrier  20  therebetween. Clamping members  70  and  72  apply sufficient clamping force for the stripping of the coating or jacket.  
         [0034]     Resilient clamping members  70  and  72  should be sized and/or selected of a material such that the resilient clamping members may hold the coated transmission carrier  20  with a clamping force suitable to hold the transmission carrier and allow the fiber or wire to be stripped without damaging the fiber or wire. However, the coated transmission carrier  20  should not be gripped so tightly that the inner transmission carrier portion  20   a  is damaged. Rather, the clamping force should suitably hold the transmission carrier and to allow stripping of the end portion of outer material while inhibiting buckling during the stripping of the outer material.  
         [0035]     Alternatively, or in addition to resilient clamping members  70  and  72 , an alignment mechanism may include a relief passage  74  disposed in at least one grip member toe portion  25 . As shown, mating relief passages  74  and  76  may be provided opposite each other in toe portions  25  and  27 . Relief passages  74  and  76  should be sized and/or shaped large enough so as to allow for clamping and stripping, as described above. Preferably, the relief passages are made larger than the outer material  20   b  of the transmission carrier, thereby allowing resilient clamping members  70  and  72  to perform the clamping. Alternately, appropriate relief passages  74  and  76  could be used alone, without resilient clamping members  70  and  72 . In such case, the relief passages would have a predetermined size suitable for the outer diameter and/or shape of transmission carrier being stripped. In other embodiments, relief passages  74  and  76  could also be omitted entirely, if desired performance was achieved.  
         [0036]     As shown in  FIG. 3A , a guide  78  may be provided extending from mounting structure  79  attached to end block  16 . Guide  78  extends toward toe portions  25  and  27 . The guide may include structure for heating the transmission carrier outer material for improved cutting, if desired (not shown). Alternately, guide  78  may simply provide a channel  82  for loosely guiding transmission carrier  20  toward alignment mechanism(s) located at toe ends  25  and  27  of grip members  12  and  14 . Spring member  32  may include a follower portion  80  disposed about guide  78  so as to maintain alignment of the spring member.  
         [0037]      FIGS. 3A-3F  show a sequence of stripping a transmission carrier using stripping device  10 . In  FIG. 3A , stripping device  10  is in the open position ready for receipt of a coated transmission carrier  20 . Cutting mechanism  18  and transmission carrier insert guide  58  portions will have been selected so as to fit the particular coated transmission carrier  20  to be stripped.  
         [0038]      FIG. 3B  shows the feeding of the coated transmission carrier  20  into stripping device  10  via transmission carrier insert guide  58  disposed in end block  16 . Transmission carrier  20  may be extended all the way through stripping device  10  past toe ends  25  and  27  of grip member  12 , if desired.  FIG. 3C  shows a close-up of the position of cutting mechanism  18  in end block  16  at this point. It should also be understood that stripping device  10  may be utilized to cut substantially shorter portions of transmissions carriers, (i.e. transmission carrier portions not extending to toe ends  25  and  27 ).  
         [0039]      FIG. 3D  depicts stripping device  10  after the pivoting of grip members  12  and  14  together so as to clamp coated transmission carrier  20  between resilient clamping members  70  and  72 , and held within relief passages  74  and  76 . As shown in  FIG. 3E , at this point blades  42  and  44  of cutting mechanism  18  at least partially cut through the outer portion of transmission carrier  20  creating an end portion  22  to be stripped off.  
         [0040]      FIG. 3F  shows the pulling of coated transmission carrier  20  away from end block  16 , thereby stripping end portion  22  from a portion of carrier  20   a . Buckling is inhibited along the stripped portion because resilient clamping members  70  and  72  grip and pull end portion  22  allowing for relatively long strip lengths, more accurate stripping, and inhibiting damage to the signal carrying optical fiber or wire within the transmission carrier. Further pulling of coated transmission carrier  20  from stripping tool  10  removes end portion  22  leaving the stripped transmission carrier  20   a  exposed for further termination procedures.  
         [0041]     Various options and modifications are possible for the device of  FIG. 1 . By way of example,  FIG. 7  depicts a modified stripping device  110  that is similar to stripping device  10 . Stripping device  110  includes a guide that acts as a fracture mechanism  178  in addition to alignment. Specifically, fracture mechanism  178  is movable in the direction of the arrow for providing a force for inducing material fracture of, for instance, the optical fiber upcoating or buffer layer during stripping. As shown, the arms (not numbered) of spring member  132  are mounted in the forward position so the body portion  132   a  of spring member moves away from cutting mechanism  118  when grip members  112 ,  114  are pushed together. In this embodiment, arms (not numbered) include protrusions  132   b  that provide a suitable clamping force so that fracture mechanism  178  grips the outer material being removed, but does not damage the optical fiber or other transmission carrier. Additionally, fracture mechanism  178  is attached to body portion  132   a  so that it moves therewith when the grip members are pushed together, thereby applying the pulling force on the outer material such as the optical upcoating or buffer layer while cutting. Any suitable means may be used for attaching fracture mechanism  178  to body portion  132   a  such as removable or fixed means. Examples include pinned together, snap-lock engagement, adhesive and other known means are also possible.  
         [0042]      FIG. 8  shows another fracture mechanism in schematic form that moves for inducing material fracture of the outer material. As shown therein, one or more driven capstan assemblies  284  and  286  may be provided for pulling an outer material of transmission carrier  20  away from blades  242  and  244  during use of the device. Such capstan assemblies could be mounted to either of the end block or one or more grip members of a stripping device. In this case, rotational input would be provided to drive pins  288  and  290  of the capstan assemblies when the blades  242 ,  244  or grip members are brought together for cutting. Such pulling force provides the added benefit of beginning to move the cut end portion of outer material from the transmission carrier at the time the cut is made. Thus, when the operator pulls on the transmission carrier, a slight separation is already in place in the outer coating, thereby allowing for improved stripping performance.  
         [0043]      FIG. 9  shows another alternate fracture mechanism structure. As shown, a leaf-spring assembly  392  is provided that clamps and pushes on the outer material of the transmission carrier. Again, the leaf-spring assembly may be attached to either the end block or one or more of the grip members or in other suitable ways. When the grip members are brought together to cut the outer material of the transmission carrier, a clamping force is created on the transmission carrier between two springs  394  and  396  of leaf-spring assembly. Additionally, a slight pulling force may also be provided, as discussed above, as leaf springs  394  and  396  slide by virtue attachment to an end block or other movable component of the strip device. Both of the structures shown in  FIGS. 8 and 9  provide a clamping force onto the outer material without damaging the transmission carrier as described above, but also provide the added benefit of a slight pulling force at the time of cutting, which is beneficial in some applications. Thus, the structures of  FIGS. 8 and 9  may be used to supplement and/or substitute for the alignment mechanisms described above for creating a fracturing force and/or movement to induce material fracture.  
         [0044]      FIGS. 10   a - 10   c  depict different blade configurations that can be used with the stripping device concepts of the present invention.  FIGS. 10   a  and  10   b  are used for cutting into a portion of the outer material while inhibiting damage to the transmission carrier. Likewise,  FIG. 10   c  depicts blades for cutting into the outer material, but in this case are intended for cutting while being rotated during the stripping process. Any suitable means or method can be used for rotating the blades. As best shown in  FIG. 3E , blades are aligned to abut each other, but in other configurations it is possible to offset the blades so that adjacent planar faces slide against each other.  
         [0045]     Many modifications and other embodiments of the present invention, within the scope of the appended claims, will become apparent to a skilled artisan. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed herein and that modifications and other embodiments may be made within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.