STRIPPING DEVICE WITH ALIGNMENT MAINTAINING FEATURE FOR IMPROVING STRIP PERFORMANCE

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. Patent 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's metal carrier out of the protective coating "downstream" of the blade members, thereby stripping the inserted wire. U.S. Patent 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, hi 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. 3 A is a cross-sectional view of the device of FIG. 1 taken along lines 3A-3A in

FIG. 2.

[0014] FIG. 3B is a cross-sectional view of the device as in FIG. 3 A 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.

3 A 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 3D.

[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. 10a- 10c 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 20a that carries the signal and an outer material such as a coating or jacket (not numbered) that protects transmission carrier 20a. [0030] As shown in Fig. 3 A, 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. 3 A. 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. 3 A 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 20b, 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. 10a 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. 3 C, 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 20a 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 20b 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. 3 A, 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. 3 A-3F show a sequence of stripping a transmission carrier using stripping device 10. In Fig. 3 A, 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 20a. 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 20a 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 132a 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 132b 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 132a 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 132a 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. 10a- 10c depict different blade configurations that can be used with the stripping device concepts of the present invention. Figs. 10a and 10b are used for cutting into a portion of the outer material while inhibiting damage to the transmission carrier. Likewise, Fig. 10c 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.