Abstract:
Apparatus and methods permit splicing or joining a plurality of tubing ends. A central tubular member has a fluid passage therethrough. The tubing ends are mounted over the extremities of the tubular member, and are held in place by a multi-part sleeve around the central member and cooperating detents (on the exterior of the tubular member and on the interior of the sleeve) that pinch or bite the tubing when the sleeve is actuated (such as via a turnbuckle action) to force cooperating pairs of the detents toward each other.

Description:
This application is based on Provisional Application Ser. No. 60/313,067 with a filing dated of Aug. 16, 2001. 

   BACKGROUND OF THE INVENTION 
   This invention relates generally to methods and apparatus for joining or splicing tubing, and specifically to methods and apparatus to simultaneously engage a plurality of tubing ends. 
   There are many situations and applications that require splicing or connecting tubing to other tubing, or to other devices or the like. Prior art approaches include using a sleeve around a central nipple or tubular member, with the tubing end disposed and gripped between the sleeve and nipple. Force or friction is applied to cause detents or teeth on the respective sleeve and nipple pieces to bite into the tubing and hold it in the desired location. Many applications require that this be accomplished with a sufficiently tight seal to prevent leakage. 
   Among the various approaches in the prior art, some apply force to the detents or teeth via threads acting between the central member and the sleeve, so that rotating those pieces with respect to each other forces the teeth or detents to move axially toward each other and “bite” into the tubing end.  FIG. 1   a  illustrates this prior art concept. Sleeve B and central member C can be rotated with respect to each other so that they are moved axially with respect to each other. Rotation in the proper direction moves the sleeve B to the left relative to member C and engages tubing D between teeth or detents E and F. 
   For applications in which two pieces of tubing are to be joined to each other, prior art approaches such as just described require that a mirror image of the apparatus be provided or formed on the other end of the central member. Not only is more material required (in order to provide the additional length of the central member, as well as the two separate mating sets of threads—one mating set at each end of the central member), but the assembly of the two ends to the splicing apparatus requires two separate rotations of threaded elements—one rotation or tightening/biting for each tubing end. 
   OBJECTS AND ADVANTAGES OF THE INVENTION 
   It is, therefore, an object of the invention to provide an improved method and apparatus for splicing tubing, which simplifies the elements and process required to join a plurality of tubing ends. 
   The preferred embodiment of the invention provides a central tubular element having a central passageway to permit fluid communication therethrough, such as from a first piece of tubing joined to one end of the central element, through the passageway, and to a second piece of tubing joined to another end of the central element. Biting or retaining elements such as cooperating detent members are positioned at extremities of the passageway on the exterior of the tubular element, and also on the interior of a multi-piece sleeve member positioned around the tubular element. The respective retaining elements or cooperating detent members are positioned to engage the first and second pieces of tubing after those tubing pieces are inserted between them (at the respective ends of the central element). The sleeve member preferably includes actuating elements such as threads acting between the multiple sleeve pieces, so that a single action by a user (such as rotating those sleeve elements with respect to each other) can force the pieces in relatively opposing directions, thereby “simultaneously” engaging each respective pair or group of cooperating detent members with its respective tubing piece. Thus, instead of having multiple sets of threads each requiring its own turning (to tighten or bite into the tubing), the preferred embodiment of the invention uses a single set of threads and a single turning action to bite into multiple tubing ends at the same time. 
   Another object of the invention is a method that uses apparatus of the aforementioned character, to simplify the assembly or splicing of a multiplicity of tubing pieces. 
   Other objects and advantages of the invention will be apparent from the following specification and the accompanying drawings, which are for the purpose of illustration only. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1   a  is a partial sectional view illustrating a prior art approach to joining or splicing tubing. The right-hand end of the assembly (not shown) could be a mirror image of the illustrated left end, or could be otherwise formed or attached to a separate element; 
       FIG. 1   b  is an exploded view of a preferred embodiment of the invention, prior to assembly; 
       FIG. 2  is similar to  FIG. 1   b , but shows only the two preferred sleeve elements as they can be assembled with each other; 
       FIG. 3  also is similar to  FIG. 1   b , but shows the entire preferred assembly as it is about to be engaged to tubing pieces; 
       FIG. 4  is a sectional view taken along line  4 — 4  of  FIG. 3 ; 
       FIG. 5  is similar to  FIG. 4 , but illustrates the tubing pieces after they have been engaged with the other apparatus; and 
       FIG. 6  is a partial sectional view taken along line  6 — 6  of FIG.  5 . 
   

   DESCRIPTION OF PREFERRED EMBODIMENT 
   A preferred embodiment of the invention is illustrated in  FIGS. 1   b - 6 . Preferably, a central tubular member  12  and a multi-part sleeve member (shown as consisting of first sleeve element  14  and second sleeve element  16 ) cooperate to retain tubing ends  50  and  52  and permit flow therebetween. 
   Persons of ordinary skill in the art will understand that the various elements of the invention can be fabricated from any of a wide range of suitable materials and methods of manufacture. Preferably, the tubing elements  50  and  52  are extruded or otherwise fabricated from a tough, pliable, somewhat plastic material, so that it can be readily flexed, opened, inserted, and “bitten” as described herein. The coupling or splicing components  12 ,  14 , and  16  are preferably injection molded from lightweight, suitably strong plastic or similar material, but again, can be fabricated from a wide variety of suitable materials. 
   In addition, persons of ordinary skill in the art will understand that the elements can range widely in their dimensions, so long as their relative sizes allow them to interact in the manner described herein. 
   Persons of ordinary skill in the art will further understand that the engagement between the tubing elements  50  and  52  and the other elements  12 ,  14 , and  16  is illustrated as utilizing conventional cooperating barbs or teeth. In the drawings, and particularly in  FIG. 6 , barb  22  on a first end of the central member  12  cooperates with barb  26  on the interior of sleeve element  14  to eventually “bite” the tubing end  50 . Barb  32  on a second end of the central member  12  similarly cooperates with barb  36  on the interior of sleeve element  16  to “bite” tubing end  52 . As explained below, in the preferred embodiment, those barb pairs  22 / 26  and  32 / 36  preferably have an interference fit, illustrated by gap G in FIG.  6 . 
   Although the precise arrangement of the barb elements can vary widely, persons of ordinary skill in the art will understand that preferably the innermost barbs  22  and  32  on the central tubular member  12  are the location at which the desired “biting” or retention of the tubing occurs, and that the outermost barbs  24  and  34  are slightly smaller than their adjacent barbs  22  and  32 , and help to keep the tubing centered, among other things. Accordingly, among the many alternative embodiments of the invention (not shown) would be an internal tubular member such as  12  but having only the “biting” interference barbs  22  and  32 , and not having the centering barbs  24  and  34 . 
   Moreover, persons of ordinary skill in the art will understand that, as an alternative to the conventional barbs illustrated in the drawings, any suitable engagement means can be utilized to retain the tubing ends between the central tubular member and the sleeve portions (including, by way of example and not by way of limitation, serrated teeth, interrupted barbs, hooks, other interfering structures or elements, or the like). Persons of ordinary skill in the art will also understand that the particular number of barbs and their relative size and spacing from each other can range widely, so long as the desired engagement of the tubing is provided as described herein. 
   The force applied to “bite” the barbs or teeth into the tubing is preferably supplied by interaction between the two sleeve parts  14  and  16 . As best illustrated in  FIGS. 5 and 6 , in the preferred embodiment shown in the drawings, the interaction is provided by screw threads  18  formed on the exterior of sleeve element  14 , that engage a corresponding threaded groove on sleeve part  16 . Persons of ordinary skill in the art will understand that the male/female aspects of the threads may be switched in alternative embodiments (so that the thread and not the groove is on the inside of the sleeve portion  16 ), and that other methods of force generation (not shown) may be provided between the sleeve portions  14  and  16  to accomplish the desired “biting” or other retention of the tubing elements  50  and  52 . By way of examples and not by way of limitation, the biting can be provided by an over-center latch (not shown) acting between the sleeve portions  14  and  16  to push them apart from each other, or by one or more adjustable screws mounted on the exterior of the sleeve portions  14  and  16  (with the screw(s) oriented parallel, perpendicularly, or otherwise with respect to the longitudinal axis of the central tubing member  12 ). 
   In the preferred method of assembly, the sleeve parts  14  and  16  are threaded together nearly as far or as far as they can be threaded onto each other. That assembly of parts  14  and  16  to each other can occur first (as illustrated in FIG.  2 ), and that assembly of parts  14  and  16  can then be forced over the central tubular member  12 . Alternatively, and as illustrated in  FIG. 1   b , the sleeve portions  14  and  16  can be placed over the central member  12 , and engaged to each other while surrounding that central member  12 . 
   Preferably, the interfering barbs  26  and  36  both end up axially between the central member&#39;s interfering barbs  22  and  32 , as illustrated in  FIGS. 3 and 4 . In that interim arrangement, tubing  50  and  52  is not yet involved in the assembly, and preferably interference between the barbs  26  and  36  on the sleeve portions and the respective inner-most barbs  22  and  32  on the central tubular member prevents the sleeve parts  14  and  16  from falling “off” the central tubular member  12  during shipment or handling, etc. 
   Preferably, the sleeve parts  14  and  16  are “loose” around the tubular member, to facilitate insertion of the tubing  50  and  52 . In alternative methods and systems, the sleeve parts could be tightened outwardly (again, in turnbuckle fashion) to snug up to the interfering barbs  22  and  32  and therefore not be “loose” on the central tubular member  12  during shipment and handling. In such alternative embodiments, the sleeve portions  14  and  16  would normally have to be rotated to shorten the sleeve combination  14 / 16  and thereby “loosen” the interference relationship between the barb pairs  22 ,  26  and  32 ,  36 , before the tubing ends  50  and  52  could be inserted. 
   The preferred interference between barbs  26  and  36  is illustrated as gap G in FIG.  6 . In other alternative embodiments, the barb pairs  22 ,  26  and  32 ,  36  may not actually be an interference fit with each other, but instead may be so closely dimensioned that the insertion of the tubing end  50  or  52  results in an interference relationship, providing the desired engagement of the tubing end. In the preferred embodiment, the ID of the interior barbs  26 ,  36  is preferably smaller than the OD of their corresponding barbs  22 ,  32 . In that arrangement, even greater force can be applied (via twisting the threads out in the manner of a turnbuckle) than would be withstood by the aforementioned alternative embodiment, thereby permitting an even stronger clamping effect between the barbs and the tubing end. 
   In the preferred method, the tubing ends  50  and  52  are then inserted onto the central nipple or tubular member  12 , and pushed over the barbs  22 ,  24  (or  32 ,  34  on the other end) and under the respective sleeve barb  26  or  36 . Preferably, the tubing is inserted all the way up against the stop rib  40 , although close to the rib  40  is probably sufficient for many embodiments, so long as the insertion provides enough tubing material between the barbs for the desired “biting” and retention. Following insertion of both tubing ends  50  and  52 , the sleeve portions  14  and  16  preferably are manipulated (such as by rotating them with respect to each other) to force them axially outward and to cause “biting” engagement of the tubing between the barbs, as shown in FIG.  4 . Preferably, further rotation of the sleeve portions  14  and  16  with respect to each other results in tighter “biting” or engagement of the tubing ends  50  and  52 . 
   The apparatus and methods of the invention have been described with some particularity, but the specific designs, constructions and steps disclosed are not to be taken as delimiting of the invention. Obvious modifications will make themselves apparent to those of ordinary skill in the art, all of which will not depart from the essence of the invention and all such changes and modifications are intended to be encompassed within the appended claims.