Abstract:
A hand tool is operable to crimp a tubular metal contact member concentrically about the stripped end portion of an insulated fiber optic light-wave conductor in spaced relation to the free end extremity thereof. A tensioning arrangement tensions the excess portion of the conductor that extends beyond the contact member, whereupon a cutting device engages the tensioned portion of the conductor to sever cleanly the excess extremity from the conductor. The tensioning arrangement serves to deflect the conductor excess end portion obliquely outwardly relative to the longitudinal axis of the conductor. Tensioning is achieved by a deflecting disk positioned normal to the longitudinal axis of the light-wave conductor, or by a guide bore contained in a conductor guide device attached to the tool body. Preferably, two contact members are simultaneously crimped on a pair of conductors, and the excess ends of the conductors are simultaneously tensioned and severed.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     A hand tool is operable to crimp a tubular metal contact member concentrically about the stripped end portion of an insulated fiber optic light-wave conductor in spaced relation to the free end extremity thereof. A tensioning arrangement tensions and stresses the excess portion of the conductor that extends beyond the contact member, whereupon a cutting device engages the tensioned portion of the conductor to sever cleanly the excess extremity from the conductor. 
     2. Description of Related Art 
     This invention relates to a hand tool for the processing and final assembly of an insulated optical fiber light-wave conductor, including at least one crimping die for crimping a tubular contact upon the stripped bare end of at least one light-wave conductor, and mechanical transverse cutting means for severing off the excess length of the stripped bare conductor end. 
     Tools of this kind are known as such, for example, from DE 198 42 122 C2 or DE 100 56 780 A1. 
     The known tools, of course, require further optimization, on the one hand, regarding their handling and, on the other hand, regarding the quality of the cut needed for cutting through the light-wave conductors. 
     SUMMARY OF THE INVENTION 
     Accordingly, a primary object of the invention is to provide a hand tool for crimping a tubular metal contact member concentrically about the stripped end portion of an insulated fiber optic light-wave conductor in spaced relation to the free end extremity thereof. A tensioning arrangement stresses the excess portion of the conductor that extends beyond the contact member, whereupon a cutting device engages the stressed portion of the conductor to sever cleanly from the conductor the excess bare conductor end. 
     According to a more specific object of the invention, the tensioning arrangement serves to angularly deflect the conductor excess end portion relative to the longitudinal axis of the conductor. Tensioning is achieved by a deflecting disk positioned normal to the longitudinal axis of the light-wave conductor, or by a guide bore contained in a conductor guide device attached to the tool body. Preferably, two contact members are simultaneously crimped on a pair of conductors, and the excess ends of the conductors are simultaneously tensioned and severed. 
     Accordingly, the tool is characterized according to the invention by the provision of at lest one of the following functions:
         (a) the mechanical transverse cutting devices are designed for adjusting the length of the light-wave optical conductors during or after the crimping of the light-wave conductor(s) during the same actuation movement with which the crimping is done, and/or   (b) during the separation cut for cutting through the light-wave conductor, the mechanical transverse cutting device keeps at least one light-wave conductor under tension at an angle with respect to the longitudinal axis of the conductor in the plugs.       

     According to feature (a), the handling of the tool is definitely simplified. This is advantageous especially when the tool is designed as manual pincers because, in that way, one can do both the crimping and the separation of the conductor or the conductors with just one flick of the wrist. According to feature (b), the adjustment of the length of the light-wave conductor is performed in a particularly neat fashion because the pre-stress results in a particularly neat separation cut. 
     This separating cut, as a rule, is so good that there is no need for any further follow-up polishing of the cutting surface of the light-wave conductor, used in combination. 
     A particularly multi-functional hand tool is created when it has devices for the performance of the functions adjusting the length of the light-wave conductors, crimping the plugs or contact members on the light-wave conductors, cutting the light-wave conductors to the right length, and crimping a traction release on a housing to receive the plugs. 
     When constructed as a manually operable hand tool, the tool has two relatively mutually movable handle grips and one tool body, whereby the pincers head furthermore has two relatively mutually movable, in this case pivotable, processing jaws, which can be pivoted between opened and closed positions and which, during their interplay, form the handles, whereby in or on the crimping jaws, there are made tools as devices for the performance of one or several of the abovementioned functions. 
     It is particularly desirable that the hand tool comprises two cross-cutting stripping knives, which are attached laterally upon the processing jaws and which have the corresponding cutting areas, because in that way, the cross-cutting function also, using the tool, is constructively advantageously integrated into the tool and the length adjustment can be performed without any problems. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects and advantages of the invention will become apparent from a study of the following specification, when viewed in the light of the accompanying drawing, in which: 
         FIGS. 1   a  and  1   b  are front right-hand and left-hand perspective views of the crimping and cutting tool of the present invention, 
         FIG. 2   a  is a detailed perspective view of the tool of  FIG. 1   b  when in the open condition,  FIG. 2   b  is a detailed front perspective view of the front portion of the tool of  FIG. 2   a ,  FIG. 2   c  is a detailed view of the tool of  FIG. 1   a , and  FIG. 2   d  is a corresponding view with certain parts removed for purpose of illustration; 
         FIG. 3   a  is a detailed perspective view illustrating the operation of the stripping means of  FIG. 1   b ,  FIG. 3   b  is a detailed perspective view illustrating the support of a pair of contact members prior to the crimping operation;  FIGS. 3   c  and  3   d  are detailed perspective views illustrating the crimping to the contact members onto the light-wave conductors,  FIGS. 3   e - 3   h  are detailed perspective views illustrating the operation of the cutting means of  FIG. 1   a ; and  FIG. 3   i  is a detailed perspective view of a final crimping step of the invention of  FIG. 1   a;    
         FIG. 4  is a perspective left hand view of a second embodiment of the crimping tool of the present invention; 
         FIG. 5  is a detailed right-hand view of the tool of  FIG. 4 ; 
         FIG. 6   a  is a front perspective view of the tool of  FIG. 5 , and  FIG. 6   b  is a sectional view of the cutting blade means of  FIG. 6   a;    
         FIG. 7   a  is a detailed front perspective view of the tool of  FIG. 6   a ; and 
         FIG. 7   b  is sectional view of the light-wave conductor deflecting means of  FIG. 7   a.    
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring first more particularly to  FIGS. 1   a ,  1   b , and  2   a - 2   c . the crimping and cutting tool  1  of the present invention includes a vertical sheet metal body portion  5  integrally connected with a first operating handle  3 , and a second operating handle  4  pivotally connected with the tool body by a conventional toggle linkage arrangement including clamping toggle lever  13  that is connected by pivot shaft  11  with the tool body, toggle lever  12  that is secured to handle  4  and is pivotally connected with toggle lever  13  by pivot shaft  15  and an intermediate lever, and operating strut  14  that is pivotally connected between toggle lever  12  and the handle  3 . Upper crimping jaw  8  is secured to the tool body  5 , and lower crimping jaw  9  is connected with the clamping toggle arm  13 . Consequently, when the handles  3  and are pivoted together, the crimping jaws  8  and  9  are brought together toward a crimping position (shown in  FIG. 3   d ). The handles are provided with hand grip cover members  6  and  7 , respectively. 
     Fastened to the sides of the crimping jaws  8  and  9  are two knife-supporting plates  16  and  17  provided with transversely-arranged upper and lower stripping knives  18  and  19 , respectively, which knives serve to strip the insulation layer from the insulated glass-fiber or polymer optical light-wave conductors  2 , as will be described below. The adjacent faces of the crimping jaws contain cooperating opposed first crimping recesses and projections  20  and  21  that serve to crimp tubular metal contacts  40  and  41  ( FIG. 3   b ) to the light-wave optical conductors  2 , and with an opposed pair of second recesses  22  that serve to crimp the tension collar  42  ( FIG. 3   i ) of a protective outer housing  43  to the pair of conductors  2 , as shown in  Figs. 1   a ,  1   b , and  3   i.    
     Fastened to the lower crimping jaw  9  is a horizontal contact member support tray  23  having a vertical rear stop wall  24  that contains a pair of through openings  25  and  26  ( FIGS. 2   c  and  2   d ) adapted to receive the stripped bare end portions  2   a  of the insulated optical light-wave conductors. Opposite these openings is a deflecting disk  28  that is rotatably mounted on the horizontal shaft  33  that is bolted to the jaw  9 . The deflecting disk  28  has a sloped edge portion  31  ( FIG. 3   g ) that deflects the stripped end portions  2   a  of the optical conductors outwardly, as best shown in  FIGS. 3   g  and  3   h . A cutting arrangement  27  includes a circular knife  29  carried by a pivot lever  30  (FIG.  3   h ) for displacement by actuating lever  32  and handle  4  from a retracted position ( Figs. 1   a ,  2   c ,  2   d ) toward a cutting position ( FIGS. 3   e  and  3   h ) relative to the deflecting disk  28  and the contact member support means  23 . During the pivotal displacement of lever  30  and circular knife  29  toward the cutting position, the knife is rotated by means of ratchet  37  ( FIG. 2   d ) and first and second pawl means  38  and  44 , respectively. 
     Operation 
     In operation, assume that two tubular metal contact members  40 ,  41  are to be crimped simultaneously onto two optical light-wave conductors  2 , respectively, and then be enclosed in a protective metal housing  43  having a strain-relieving portion  42 . 
     The outer insulation layers of the relatively delicate polymer or glass fiber optical fiber light-wave conductors  2  are stripped from the end portions  2   a  of the conductors by inserting the conductors on support recesses  35  and  36  ( FIG. 3   a ) between the stripping knives  18  and  19 , and by pivoting the handles  3  and  4  together to sever the insulation layers without any cutting engagement with the optical fiber conductors, whereupon the conductors are longitudinally displaced to strip the severed insulation layers from the bare conductor ends  2   a.    
     The tubular contact members  40  and  41  are then deposited on the support tray  23 , with corresponding end portions of the contact members being arranged in the recesses of the crimping sets  20  and  21  ( FIG. 3   b ). The bare stripped ends  2   a  of the optical conductor  2  are then inserted longitudinally into the contact members ( FIG. 3   d ), with the excess ends of the bare conductors  2   a  extending from the openings  25  and  26  contained in the support tray stop wall  24  ( FIGS. 3   g  and  3   e ). During this insertion step, the relatively delicate bare end portions  2   a  of the optical conductors are angularly deflected obliquely outwardly by the sloped surface  31  of the deflecting disk  28  ( FIG. 3   g ), thereby to tension and stress the conductors adjacent the deflecting disk  28 . The handles  3  and  4  are subsequently pivoted together to cause actuation lever  32  to pivot the cutting lever  30  toward the gap between the deflecting disk and the tray stop wall  24 , with the cutting disk being rotated by the cooperation between the ratchet  37  and the pawls  38  and  44  ( FIG. 2   d ). Owing to the tensioning of the stripped bare ends  2   a  of the conductors, the excess bare conductor end portions are cleanly severed by the circular knife  29 , so that no further polishing of the cut end surfaces of the optical conductors is required. 
     The handles  3  and  4  are separated to open the crimping jaws  8  and  9 , whereupon the protective metal sleeve  43  ( Figs. 1   a ,  1   b  and  3   i ) is slipped over the the contact members. The traction relief portion  42  of the sleeve  43  is then inserted between the jaw recesses  22 , as shown in  Figs. 1   a ,  1   b , and  3   i , and the handles are squeezed together to crimp the traction relief portion  42  to the conductor assembly, whereupon the handles are opened to complete the assembly process. 
     The hand tool  1  is especially designed for the assembly of two insulated light-wave conductors  2  with one plug connection device, in particular, so-called POF (polymer optical fiber) duplex light-wave conductors and contact member connection devices. The assembly process using the hand tool of the present invention can be done in such a way that, as a rule, there will be no need for any subsequent polishing of the light-wave conductor cutting surface. For this purpose, the tool offers devices in the preferred embodiment shown in  FIG. 1  for the performance of the functions of transverse-cutting and stripping the insulation layer of the POF light-wave conductors, crimping the contact members upon the POF light-wave conductors, severing the POF light-wave conductors to the right length, and crimping a traction relief sleeve upon the contact set. It should be noted that it is particularly advantageous to combine all of these functions in one tool. But in the context of this invention, it is not absolutely required that all of these functions be integrated in just one single manual pincers. 
     By closing the tool head/bit, the light-wave conductors  2  in the process are positioned and fixed in guides  35 ,  36  in the counter-die and in the bottom ram or in the processing cheeks in the correct place. It is not necessary to strip light-wave conductors of their jacket to a precise length because the final separation of the light-wave conductors  2  takes place only during the subsequent crimping step during which they are automatically cut to the right length. 
     This final severing of light-wave conductors  2  in this case is done advantageously during the same closing motion of the handles during which the crimping of the light-wave conductors ends also takes place. 
     During the insertion of the contact members toward engagement with stop wall  24 , an elastically positioned end of the contact members plugs  40 , 41  bumps against the circular knife  29  so that the tolerances of the individual parts of contact members s  40 ,  41  are balanced out, and contact members  40 ,  41  will lie almost without play upon circular knife  29 . As indicated above, during the introduction of both POF light-wave conductors  2  into contact members  40 ,  41 , the stripped light-wave conductor ends  2   a  engage an inclined surface  31  of the press-on disc  28  ( FIG. 2   b ) and in this way slide along this slope  31  in such a way that the POF light-wave conductors are deflected in receiving area  23  relatively easily for the alignment of the longitudinal axis of the conductors in contact members  40 ,  41  ( FIG. 3   d ). The deflection disk  28  lies along the prolongation of the longitudinal conductor axis in passage openings  25 ,  26  so that the light-wave conductors must be placed obliquely around that obstacle, something that causes a slight pre-stress, which thus definitely improves the cut image. 
     By bending or deflecting the light-wave conductor ends  2   a , they are placed under stress, which during the subsequent severing separation of light-wave conductors  2  causes a protruding cutting surface that does not have to be subjected to any further polishing. The attenuation at the cutting site is already mostly reduced by the cut itself. The user in this way can easily cut the POF light-wave conductors  2  using the same closing motion that is used to crimp plugs  40 ,  41 . The cut in the final analysis again runs at a right angle with respect to the light-wave conductor so that the light-wave conductor will close flush with the plug. To optimize the cutting surface on the light-wave conductors, circular knife  29  is made to rotate (see also  FIG. 2   c ) This is done ( FIG. 2   d ) by the pivotal motion of lever arm  30  of the ratchet gear  37  and of detent pawl  38  and a second detent pawl  44 . The first detent pawl  38  is firmly connected with receiving area  23 , ratchet gear  37  is firmly connected with knife  29 , both of which being positioned together on an axis in a rotary fashion. If lever arm  30  is now actuated, the first detent pawl  38  will press upon the ratchet gear  37  and thus causes knife  29  to rotate. Detent pawl  44  prevents the ratchet gear  37  and thus also the circular knife  29  from turning backwardly, something that has the advantageous consequence that the knife is used during every cut at another site. 
     For traction relief purposes, crimp forging die  22  is made or arranged up front in the jaw pincers so that the preassembled unit with the components including contact members  40 ,  41 , housing  43 , cable traction relief sleeve  42  can easily be inserted into and removed from the crimp forging die  22 . 
     In the alternate embodiment of  FIGS. 4 and 5 , instead of using deflection disk  28  of the first embodiment discussed above, deflection of the bare conductor ends  2   a  is produced by deflection guide means  49  that are fastened to the stop end wall  24  of the contact member support tray  23 . As best shown in  FIG. 7   b , the deflection guide means include through bores  55  and  56  ( FIG. 5 ) that progressively widen such that the stripped bare conductor ends  2   a  are deflected obliquely angularly outwardly relative to the longitudinal axes of the conductors  2 . The circular cutting blade  29  is displaced by operation of the handles  3  and  4  to extend into gap  50  adjacent stop wall  24 , thereby to sever the stressed, tensioned portions of the bare conductor ends  2   a  During this displacement of the cutting blade, it is rotatably driven by the ratchet gear  37  secured to shaft  51  ( FIG. 6 ). During the cutting operation of the optical conductor bare ends, the circular blade  29  is supported by the annular collar portion  53  of a support disk  128  that is biased toward the circular cutting blade by spring washer  52  which reacts with washer  34  mounted on bolt  33 . 
     In order to support the outer circumferential surfaces of the optical conductors during the insulation-stripping step, a pair of guide plates  61  and  61  ( FIG. 4 ) are fastened to the sides of the tool body  5  adjacent the stripping knives  16  and  17 , which plates are proved with opposed support recesses  63  that receive and support the optical conductors. These guide plates  61 ,  62  are pressed against each other during the stripping action, except for recesses  63 ,  64  that form the passage openings for the light-wave conductors  2 . Guide plates  61 ,  62  improve the cutting quality during the insulation step in that they prevent any damage to the actually light-conducting fibers of the light-wave conductor. Moreover, the manual force needed to extract the fibers is reduced and it is thus possible to prevent any damage to the fibers by the stripping knives  16 ,  17 . 
     According to another feature, the contact members  41  and  42  seated on the support tray  53  are axially biased toward the stop wall  24  by leaf spring means  46  ( FIGS. 5 and 7   b ), thereby to stabilize the contact members while the adjacent ends thereof are crimped to the bare conductor end portions  2   a . The leaf spring is fastened to the tool by means of a screw  47  and a nut  48  and possibly a support disc. It is arranged on the side of the tool body  5  upon which is also arranged the transverse cutting mechanism  27  for adjusting the length of the light-wave conductors  2 . Spring  46  is so designed and arranged that during the closing of the handles, it will press plugs  40 ,  41  in the direction of an abutment. Here this abutment is formed by stop  24 . In this way, it is assured that the light-wave conductors will be cross-cut at the right axial point because contact members  41  are specifically made to rest against the abutment against which they are forced by spring  46 . Spring  46  thus acts like an automatic positioning aid for contact members  41  (see also  FIG. 6   a ). 
       FIG. 5  also shows a protective cover  60 , especially for circular knife  29 . According to  FIGS. 6   a  and  6   b , the transverse cutting mechanism  27  again has a circular knife  29 , which is rotatably positioned and which can be driven and which, by virtue of its arrangement at the end of the pivotable lever arm  30  can be so moved along a circular arc segment that, using it, one can cut during or after the crimping of any as-yet-protruding ends  2   a  of the light-wave conductors  2 . Lever arm  30  is swung as described in  FIG. 3 , illustrating the ratchet  37  and detent pawl  38  that turn or drive the circular knife. By virtue of its arrangement on lever arm  30 , circular knife  29  can be swung into a gap area  50  ( FIG. 7   b ) between seat  24  and guide means  49 . Circular knife  29  rests directly against ratchet gear  37  and is connected to it in a non-rotatable manner. On its side opposite the crown gear  37 , round knife  29  rests against a press-on disc  128 . This press-on disc  128  preferably has a diameter that is only slightly smaller (preferably a maximum of 20% smaller) than the diameter of cutting knife  29 . 
     Arranged between screw  33  and press-on disc  128  are preferably a washer  34  and a spring, in this case a spring washer  52 . The spring is used to press the press-on disc  128  against the circular knife  29 . The press-on disc  128  advantageously has an axial collar or shoulder  53 , which is used as contact area with respect to cutting knife  29 . In that way, the cutting knife is guided exactly in this area as a round knife  29  ( FIG. 6   b ) and cannot slip during the cutting of the light-wave conductors  2 . 
       FIGS. 7   a  and  7   b  show how the contact members  41  with the light-wave conductors rest in guides  49 . Guide means  49  is placed upon the tool body  5 , and preferably upon the lower crimping jaw  9 , and it is attached or molded upon the latter. Cutting knife  29  can be moved with relation to the fixed guide  49 . For example, between stop wall  24  of the receiving area  23  and guide means  49 , there is preferably provided a gap  50  in which the cutting knife  29  can dip during the cutting process. Guide means  49  furthermore has a number of passage holes  55 ,  56  (or blind holes) corresponding with the number of the light-wave conductors  2  that are to be cut. Passage openings  55 ,  56  preferably are so fashioned that they will be somewhat wider in the direction toward the free ends of the light-wave conductors  2 . In this way, the actual fiber of the light-wave conductors  2  is pushed somewhat obliquely upward by the circular knife  29  during the cutting procedure. This slight oblique position prevents the uncontrolled snapping of light-wave conductor  2 . This again facilitates a slight bend as a result of tension. The oblique position thus, however, is nevertheless so dimensioned that the actual cut will nevertheless run precisely normal with respect to the longitudinal axis of the conductor. 
     In describing preferred, exemplary embodiments, it might be noted that hereafter we describe some preferred embodiments also in detail, but that the invention is not confined to these embodiments but instead can be designed in any desired variations within the context of the claims. In particular, terms such as “above,” “below,” “in front” or “behind” must not be construed in any restrictive fashion but instead relate merely to the particularly illustrated arrangement. Moreover, when individual parts are explained, they—unless otherwise indicated—are also basically conceivable in multiple designs. The coverage furthermore also protects any functional reversals of the illustrated arrangements or procedures as well as equivalent designs. 
     While in accordance with the provisions of the Patent Statutes the preferred forms and embodiments of the invention have been illustrated and described, it will be apparent to those skilled in the art that changes may be made without deviating from the invention described above.