Abstract:
A fibre optic coupler assembly for optically aligning a sectioned fibre optic cable, the cable having a first end and a second end and comprising one or more fibre optic cores. The assembly comprises a first holder for holding the first end; a second holder for holding the second end coupled to the first end; a retractor for retracting the second end; an aligning unit comprising a resilient construction having a conduit passing through it, for linear alignment of the ends; whereby the first and second ends are coupled by the respective holders and whereby the second end can be linearly aligned in the conduit of the aligning unit, retracted using the retractor, and rotated to obtain rotational alignment of the fiber cores of the ends.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a National Phase Application of PCT International Application No. PCT/IL2003/000752, International Filing Date Sep. 18, 2003, claiming priority of IL Patent Application, 151954, filed Sep. 26, 2002. 
   FIELD OF THE INVENTION 
   The subject of the invention relates to improvements to couplers for fibre optic cables. 
   BACKGROUND OF THE INVENTION 
   Prior solutions to the problem of coupling and uncoupling of fibre optic cables have been provided. European patent 0347118 provides a fibre connector for end-to-end abutment with another like fibre connector, where a fibre cable can be positioned in the connector for termination thereof. U.S. Pat. No. 5,550,944 provides a fibre optic coupling assembly that includes a coupling assembly comprised of a spring loaded coupling lock which locks two fibre connectors together by way of spring balls located in locking grooves. 
   However there are a number of limitations in prior art connectors, which can be ameliorated.
         They are manufactured for a specific cable diameter rather than accepting a range of diameters.   They do not provide an easy means for rotating multiple-core cables until correct alignment is achieved.   They require a special connector at each abutting cable section end, making it impossible to slip a device such as an angioplasty balloon over one of the cable sections.   They require high degrees of tolerance and tend to become unusable after some tens of uses due to wear.   They are expensive to manufacture due to the costs of materials and the need to maintain high tolerances.       

   Therefore, it is a main object of the present invention to provide a coupling means for coupling and decoupling a fiber optic cable, the cable comprising one or more fibre optic cores. 
   Other benefits of the present invention include:
         The exact cable diameter is not relevant.   The device operates with low tolerances, keeping it effective after many uses.   Operation is easy, with the user simply pushing down on a button or clip or pulling out and rotating a cylinder.   One or both of the cable sections can be used with the device without being fitted with a connector.   There is no ambiguity about choosing the right insertion opening for each cable end.   The components are manufactured with very loose tolerances, except for the alignment groove and the securing mechanism. In addition most of the parts can be made of inexpensive plastic. There fore the coupler is suitable for inexpensive mass production and hence can be used for disposable applications.       

   BRIEF DESCRIPTION OF THE INVENTION 
   There is thus provided in accordance with a preferred embodiment of the present invention, A fibre optic coupler assembly for optically aligning a sectioned fibre optic cable, the cable having a first end and a second end and comprising one or more fibre optic cores, the assembly comprising:
         a first holder for holding the first end;   a second holder for holding the second end coupled to the first end;   a retractor for retracting the second end;   an aligning unit comprising a resilient construction having a conduit passing through it, for linear alignment of the ends;
 
whereby the first and second ends are coupled by the respective holders and whereby the second end can be linearly aligned in the conduit of the aligning unit, retracted using the retractor, and rotated to obtain rotational alignment of the fiber cores of the ends.
       

   Furthermore, in accordance with another preferred embodiment of the present invention, the first holder comprises a first guide having a bore extending therethrough adjacent to a first cable lock also with a bore extending therethrough adjacent to the distal end of the aligning unit; the bores for receiving the first cable end. 
   Furthermore, in accordance with another preferred embodiment of the present invention, the lock comprises a spring pad connected by rods to a release button. 
   Furthermore, in accordance with another preferred embodiment of the present invention, the second holder comprises a second guide having a bore extending therethrough adjacent to a proximal end of the aligning unit, the second guide bore for receiving the second end, the second guide further equipped with a second lock. 
   Furthermore, in accordance with another preferred embodiment of the present invention, the second lock is a luer connector. 
   Furthermore, in accordance with another preferred embodiment of the present invention, the retractor comprises a spring adjacent to the second holder, the force of the spring restrained by a clip. 
   Furthermore, in accordance with another preferred embodiment of the present invention, the aligning unit comprises a first part having along a longitudinal axis a flat surface with a groove running down the middle of the surface, the groove having a diameter less than the diameter of the ends, a second part having a flat face along a longitudinal axis, the two parts held together along their flat faces by a spring mechanism, the face of the second part holding the ends in the groove of the first part, the spring mechanism holding the two parts together while enabling them to move apart when the retractor is operated, thereby allowing rotation of the second end when the second holder is rotated. 
   There is thus also provided in accordance with a preferred embodiment of the present invention, a fibre optic coupler assembly for optically aligning a sectioned fibre optic cable, the cable having a first end and a second end and comprising one or more fibre optic cores, the assembly comprising
         a means for holding the first end;   a means for holding the second end coupled to the first end;   a means for retracting the second end;   a means for resiliently linearly aligning the ends;
 
whereby the first and second ends are coupled by the respective holding means and whereby the second end can be linearly aligned in the aligning means, retracted using the retracting means, and rotated to obtain rotational alignment of the fiber cores of the ends.
       

   There is thus also provided in accordance with a preferred embodiment of the present invention, a method for optically aligning a sectioned fibre optic cable, the cable having a first end and a second end and comprising one or more fibre optic cores, the method comprising
         holding the first end;   holding the second end coupled to the first end;   retracting the second end;   resiliently linearly aligning the ends;
 
wherein the first and second ends are coupled and wherein the second end is linearly aligned, retracted, and rotated to obtain rotational alignment of the fiber cores of the ends.
       

   
     BRIEF DESCRIPTION OF THE FIGURES 
     The invention is described herein, by way of example only, with reference to the accompanying Figures, in which like components are designated by like reference numerals. 
       FIG. 1  is a longitudinal centre line section view of two fibre optic cables interconnected to an intermediate cable coupler. 
       FIG. 2  is an exploded view of the coupler shown in  FIG. 1 ; 
       FIG. 3  is a longitudinal centre line section view of a first cable used with the coupler; 
       FIG. 4  is a longitudinal centre line section view of a second cable used with the coupler; 
       FIGS. 5-15  show sequential general and detailed views of the insertion of the two parts of the cable in the coupler and rotation of one of the parts; 
   

   
       
       Part numbers used in this specification: 
         10  first cable 
         11  cable luer 
         12  second cable 
         13  sleeve 
         14  fibre 
         15  filler 
         16  fibre optic cable coupler 
         18  first cable guide 
         19  guide hole 
         20  cable locking pad 
         22  cable locking seat 
         24  cable locking cylinder 
         26  cable locking spring 
         28  cable locking spring seat 
         30  cable locking button 
         32  cable locking rod 
         34  main barrel 
         35  barrel cavity 
         36  hole for cable locking rod 
         38  channel for retention clip 
         40  alignment cylinder holder 
         41  alignment cylinder holder cavity 
         42  alignment cylinder 
         42 A grooved alignment cylinder component 
         42 B flat alignment cylinder 
         44  alignment spring component 
         46  retraction clip 
         48  retraction clip button 
         50  pressure spring 
         52  washer 
         54  second cable guide 
         55  channel 
         56  clip releasing wall 
         57  clip stop wall 
     
  
   DETAILED DESCRIPTION OF THE INVENTION 
   The present invention is a coupler for end-to-end connection of segments of cables comprising one or more fibre optic cores. 
   A typical of use of the present invention is for over-the-wire angioplasty balloon treatment, where a fiber optic cable that is collecting data in a blocked heart vessel is also used as a guide-wire for a balloon. In this application the cable must be cut at some point to allow the balloon to be attached and then reconnected. 
   With reference first to  FIGS. 1 and 2 , the fibre optic cable coupler assembly  16  can receive at opposite ends identical fibre optic cables. For purposes of description, the cables and the ends into which they fit are labeled in this specification “first” and “second.” These designations are for ease of description and do not have functional implications, i.e., first cable  10  could equally have been called second cable, and vice versa. 
   The coupler  16  comprises three primary mechanisms: a means for holding a first cable, a means for holding a second cable, and a means for rotating the second cable until the fibers align. The primary innovation of the coupler lies in the means for rotating the second cable, the heart of which is the alignment cylinder  42 , as will be explained later. 
   First cable guide  18  is a cylinder provided with a hole  19  for receiving first fiber optic cable  10 . Hole  19  widens at the proximal end to facilitate insertion of cable  10 . First cable guide  18  sits inside barrel cavity  35 , which is a cylindrical element, against cable locking cylinder  24 . 
   A means is required to lock first cable  10  in place once the cable has been inserted as far as alignment cylinder  42 . In the preferred embodiment this is implemented as a spring-actuated mechanism described below. This is a convenient locking mechanism but many other cable locking mechanisms are known to those skilled in the art. 
   Cable locking seat  22  is an elongated element that holds cable locking pad  20 . Cable locking seat  22  is pressed up by cable locking spring  26 . Cable locking pad  20  is an elongated element made from a malleable material such as rubber, that holds first cable  10  against locking cylinder  24 . 
   Cable locking spring  26  sits in cable locking spring seat  28 . Seat  28  is a cylindrical element that is threaded into locking cylinder  24 , such that spring  26  normally presses up against cable locking seat  22 . 
   When pressure is applied to locking button  30 , the button pushes down on rods  32  which in turn move down through holes  36  pushing down seat  22 . Downward movement of seat  22  releases pad  20  freeing cable  10  to move laterally between pad  20  and locking cylinder  24 . When pressure is released from locking button  30 , the mechanism works in reverse, with the result that first cable  10  is held in place between pad  20  and locking cylinder  24 . 
   Cylinder  24  sits inside cavity  35  of main barrel  34  against alignment cylinder holder  40 . Alignment cylinder  42  is a cylinder-shaped component comprising grooved alignment cylinder component  42 A and flat alignment cylinder component  42 B, held together with alignment springs  44 . When a cable  10  or  12  is inserted into the longitudinal groove running along the face of grooved alignment cylinder component  42 A, the part of the cable that extends above the surface of grooved component  42 A forces flat alignment cylinder component  42 B out against alignment springs  44 . When the insertion force stops, springs  44  keep flat component  42 B against the cable holding the cable loosely in place against grooved component  42 A. 
   It will be noted that alignment cylinder  42  is the primary component of the apparatus, providing a means for holding cables in place to make the connection between the cables but not holding the cables so tightly that the cables cannot be rotated to seek proper alignment. Since the channel holding the cables is formed from a flexible meeting of a groove with a flat surface, rather than being a fixed diameter bore, the cable does not have to be a precise diameter, rather the cable can be any diameter that extends beyond the groove up to a diameter that forces flat component  42 B to a point where it impacts on cavity  41  of alignment cylinder holder  40 . 
   Alignment cylinder  42  sits inside cavity  41  of alignment cylinder holder  40 . Alignment cylinder holder  40  sits inside pressure spring  50  and washer  52  and against second cable guide  54 . 
   Second cable guide  54  is a cylindrical element with channel  55  in its exterior surface running along the circumference to a depth adequate to hold retraction clip  46 . Clip stop wall  57  of channel  55  is perpendicular to the exterior of second guide  54  while clip releasing wall  56  is angled in about 45 degrees such that when clip buttons  48  are squeezed together, clip  46  pushes out along clip releasing wall  56  till it comes out of channel  55  releasing second cable guide  54 , which is then forced out by pressure of spring  50  against washer  52 . 
   With reference now to  FIG. 3 , first cable  10  is a typical fibre optic cable, comprising sleeve  13  and one or more optical fibers  14 . 
   With reference now to  FIG. 4 , second cable  12  is the same type of cable as first cable  10 . Second cable  12  is further fitted with a male luer connector  11  to lock cable  12  into second cable guide  54 . 
   First cable  10  and second cable  12  are two disconnected segments of a single original cable. The coupler  16  is used to reconnect the segments. 
   A means is required to lock second cable  12  into second cable guide  54  once cable  12  has been inserted through the guide to alignment cylinder  42 . In the preferred embodiment this is implemented as a male luer connector  11  at the end of cable  12  which fits into a female luer connector shape at the start of bore  56  in second cable guide  54 . 
   This is a convenient mechanism, particularly familiar in the medical environment but many other cable locking mechanisms are known to those skilled in the art. 
   With reference now to  FIGS. 5-15  the operation of the coupler will be described.
         1.  FIG. 5  shows the coupler before insertion of the cables.  FIG. 6  is a detailed view of the alignment cylinder  43 , which is empty at this point, grooved component  42 A pressing against flat component  42 B. First cable locking pad  20  is pressed up against cylinder  24 .   2.  FIG. 7  shows second cable  12  inserted through second cable guide  54  into alignment cylinder  42  and locked in place with cable luer  11 .  FIG. 8  shows in detail that the cable has pushed apart components  42 A and  42 B.   3. In  FIG. 9  first spring button  30  has been pressed down pushing down spring  26 .  FIG. 10  shows in detail that this releases pressure from locking pad  20 , thereby creating a gap between pad  20  and cylinder  24  through which cable  10  will be inserted   4. In  FIG. 11  first cable  10  has been inserted through first guide  18  to alignment cylinder  42  till it met second cable  12  and then first spring button  30  was released, allowing spring  26  to push up on locking pad  20 , thereby holding the cable against cylinder  24 .  FIG. 12  shows in detail that the two cables are now meeting in alignment cylinder  42  and that first cable is held by pad  20 .   5. At this point a measurement would be made by the machine or human operator of the coupler  16  to check the optical alignment of the cable connection that has been achieved to this point. If the alignment is not yet optimal, second cable can be retracted and rotated to improve the alignment, as described in the next step.   6. In  FIG. 13  clip buttons  48  have been squeezed together (not shown in the figure), raising legs of clip  46  up out of second guide channel  55 , thereby releasing second guide  54  which is pushed out by force of spring  50  exerted on washer  52 . Second cable  12 , which is locked (via luer  11 ) into guide  54  is retracted with the guide.  FIG. 14  shows cable  12  retracted from cable  10  in alignment cylinder  42 .  FIG. 15  shows legs of clip  46  raised out of second guide channel  55 , thereby releasing guide  54 .   7. Guide  54  is rotated, which rotates second cable  12  to improve the cable  12  alignment with cable  10 .   8. Guide  54  is pushed back in bringing cable  12  back into contact with cable  10  by releasing clip buttons  48 , causing legs of clip  46  to spring back down into second guide channel  55 , thereby locking guide  54  back in place.   9. Steps 5 to 8 are repeated until cables are optimally aligned       

   Advantageously, the above described invention accomplishes the objects as follows. The coupler  16  enables end-to-end coupling and decoupling of cable comprising multiple fibre optic cores, and further enables second cable  12  to be rotated within alignment cylinder  42  until the fiber cores  14  align. 
   Furthermore, since alignment cylinder  42  is comprised of two flexibly connected parts, grooved component  42 A and flat component  42 B, the device can accommodate a range of cable diameters and allows for loose tolerances in manufacture. This together with the inexpensive component materials makes the device suitable for inexpensive mass production, hence disposable. 
   Furthermore, the active components of the device are simple to operate and their operation can be easily automated by one skilled in the art. 
   Furthermore one or both of the cables can be used with the coupler without any connector attached, thereby enabling a balloon to be slipped over the cable so that the cable can serve as a guide-wire. 
   Furthermore, since first cable guide  18  and second cable guide  54  have different openings, there is no ambiguity about choosing the right insertion opening for each cable end. 
   Further still, the device of the present invention provides fast and reliable means for aligning multi-core optical fibers. 
   It should be clear that the description of the embodiments and attached Figures set forth in this specification serves only for a better understanding of the invention, without limiting its scope as covered by the following Claims. 
   It should also be clear that a person skilled in the art, after reading the present specification could make adjustments or amendments to the attached Figures and above described embodiments that would still be covered by the following Claims.