Patent Publication Number: US-2011071504-A1

Title: Connection device for medical tubing

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to a coupling device for releasable connection of medical tubing, such as catheters, of the type where no coupling parts are introduced into the lumen of the medical tubing. 
     BACKGROUND OF THE INVENTION 
     Medical tubings, such as catheters, are used in various medical applications. In principle, catheters are used either to remove fluid from a patient, e.g. for draining of blood etc. from wounds, or for providing fluids to the patient, e.g. for administering medicaments. For example, small catheters—typically an outer diameter size of about 2 mm is suitable—can be used for administering liquid medicaments to a patient for post-operative pain relief. 
     In use, the catheters normally need to be connected, both mechanically and fluidly, to other medical devices, such as a drug administration device. The connection to the medical tubing needs to be adequately strong, reliable and fluid tight, but it is also of importance that the flow capacity of the medical tubing is not significantly restricted. Further, the medical tubing connection operation should preferably be simple and quick. Still further, the connection should preferably be releasable, making it possible both to disconnect and reconnect the medical tubing. 
     A common type of coupling devices for medical tubing uses one part which is inserted into the lumen of the medical tubing, and another part which clamps the end part of the medical tubing between the inserted part and an outer part. An example of such a coupling device is disclosed in U.S. Pat. No. 6,971,390. However, this type of connectors has certain drawbacks. For example, arrangement of a part inside the medical tubing is relatively complicated, especially for small medical tubings, which makes the coupling process tedious and cumbersome. Further, the introduction of a part into the medical tubing lumen often leads to a restriction in the flow capacity of the medical tubing, and/or a requirement that the medical tubing is made of a flexible and elastic material. Still further, most previously known connector devices are also relatively complicated and expensive to produce. 
     There is therefore a need for a coupling device of a type without any part protruding into the lumen of the medical tubing, and which provides a quick and reliable connection of the medical tubing end, and which can be produced to a relatively low cost. 
     SUMMARY OF THE INVENTION 
     It is a general object of the present invention to alleviate the above-discussed problems, and provide a coupling device for medical tubing providing a reliable connection without any parts being inserted into the lumen of the medical tubing. 
     According to a first aspect of the invention, there is provided a coupling device for releasable connection of a medical tubing, with no coupling parts being inserted into the lumen of the medical tubing, said coupling device comprising: 
     a hollow body member having a first end for receiving a medical tubing end, an opposite second end, for conveying an input/output to said medical tubing, and an intermediate part between said first end and second end, said intermediate part being arranged to accommodate the medical tubing end inserted through said first end and having an inwardly variable diameter; and 
     compression means for providing a compression force onto said intermediate part, thereby causing a relatively uniform reduction of the inward diameter of the intermediate part; 
     wherein said relatively uniform reduction of the inward diameter of the intermediate part is arranged to occur over a substantial length, said length being at least two times the outer diameter of the medical tubing. 
     According to another aspect of the invention, there is provided a coupling device for releasable connection of a medical tubing, said coupling device comprising: 
     a hollow body member having a first end for receiving a medical tubing end, an opposite second end, for conveying an input/output to said medical tubing, and an intermediate part between said first end and second end, said intermediate part being arranged to accommodate the medical tubing end inserted through said first end and having an inwardly variable diameter; and 
     a hollow compression sleeve being arrangeable over the intermediate part of the hollow body member, and being engageable with an engagement area of said hollow body member arranged, whereby engagement between the hollow compression sleeve and the hollow body member forces the hollow compression sleeve to exert a force towards the intermediate part, thereby causing a relatively uniform reduction of the inward diameter of the intermediate part. 
     Preferably, the relatively uniform reduction of the inward diameter of the intermediate part is arranged to occur over a length being at least two times the outer diameter of the medical tubing, and preferably at least three times said diameter, and most preferably at least five times said diameter. 
     By means of this coupling device, a very strong, reliable and fluid tight connection is achievable. Since the compression on the medical tubing is applied relatively uniformly and over an extended length, a very good holding engagement is obtainable, without any significant change in the medical tubing properties. Thus, the flow of the medical tubing is essentially not affected at all when using the new coupling device. 
     Preferably, the engagement between the coupling device and the medical tubing is obtained through a friction fit. However, the alternatively or additionally, the engagement may also be a mechanical engagement, such as a mechanical interlocking. This may e.g. be obtained through a surface structure provided on either the inwardly facing coupling surface of the coupling device, or the outwardly facing surface of the medical tubing, or a combination of the two. The surface structure may e.g. comprise a roughened surface, and preferably in a certain pattern, such as grooves, protruding ribs or the like. The surface structure may also form barb-like protrusions. Further, the surface structure may comprise holes or perforations, e.g. arranged through the wall of the medical tubing. The surface structure of the end of the medical tubing and the coupling device may also correspond and match, in order to obtain a good engagement and interlocking between the parts. 
     The new coupling device is relatively simple and cost-efficient to produce, since if comprises few parts, all of which are producible with straight-forward production methods, such as by injection molding. 
     Further, the new coupling device is very fast and simple to use. The medical tubing end need only to be inserted through the first end of the hollow body member, and the compression means is moved into a position so that a compression force is applied to the medical tubing through the intermediate part of the hollow body member. Dismounting of the medical tubing is just as easy, and the medical tubing can easily be disconnected and reconnected over and over again, without damaging the medical tubing. 
     Still further, the present coupling device is useable for essentially all types of medical tubing, such as catheters, regardless of the size and material of the medical tubing. 
     However, the present invention is particularly useful for small medical tubings, such as medical tubings having an outer diameter in the range 0.5-3.0 mm, and preferably in the range 1.0-2.5 mm, and most preferably about 2 mm. 
     In particular, the present coupling device is highly suitable for connection of soft and pliable medical tubing, which tend to be deformed with previously known connection arrangements. 
     Further, by avoiding the introduction of any material into the lumen of the medical tubing, the risk for contamination is greatly reduced. By means of the present invention, the coupling device is only in contact with the outer surface of the medical tubing. Further, the connection of the medical tubing to the coupling device can be performed without touching the end of the medical tubing, or any part in the vicinity of the end, which also leads to a reduced risk of contamination. 
     The intermediate part preferably comprises a plurality of fingers, wherein the fingers are to at least some extent spaced apart in a circumferential direction. Hereby, the fingers are easily moveable inwardly and outwardly, without restricting each other. However, alternatively a solid intermediate part, e.g. made of an elastic material, is also feasible. 
     The intermediate part may be a tubular part of an elastic material, whereby the inward diameter is changeable by increasing and/or decreasing the length of the intermediate part. In such an alternative, the compression means may comprise means for changing the distance between the first and second end of the hollow body member. 
     However, preferably the compression means comprises a hollow compression sleeve being arrangeable over the intermediate part of the hollow body member, and being engageable with an engagement area of said hollow body member arranged, whereby engagement between the hollow compression sleeve and the hollow body member forces the hollow compression sleeve to exert a force towards the intermediate part. 
     The engagement between the hollow compression sleeve and the hollow body member can e.g. be by means of a friction fit and/or by means of mechanical interlocking, such as with a suitable surface structure. However, preferably the engagement occurs through a screw threading. Hereby, longitudinal displacement between the compression sleeve and the hollow body member becomes very easy and controllable by applying a rotational movement between the compression sleeve and the hollow body member. 
     The engagement area of the hollow body is preferably arranged between the intermediate part and the second end. However, the engagement area may also be arranged e.g. between the intermediate part and the first end. 
     Preferably, the intermediate part of the hollow body member comprises at least one surface tapering in the direction of the first end, and the hollow compression sleeve comprises a corresponding at least one tapering surface, whereby movement of the hollow compression sleeve over said hollow body member in a direction from said first end to said second end provides an engagement between said tapering surfaces, and thereby a compressing force on said intermediate part. 
     According to one embodiment, the intermediate part comprises one conically tapering part, and the compression sleeve comprises one or several correspondingly tapering surfaces. In case the above-discussed alternative with an intermediate part having a plurality of arms is used, the conically tapering part would in this case be divided into a corresponding number of segments. 
     According to another embodiment, the intermediate part comprises a plurality of outwardly protruding parts, said parts forming a plurality of tapering surfaces. Preferably, the protruding parts are formed as a screw threading, and whereby the at least one tapering surface of the hollow body member forms a corresponding screw threading. 
     In case both the intermediate part and the engagement area of the hollow body member engages with the compression sleeve through screw threading, the screw pitch of the screw threading between the hollow compression sleeve and the engagement area of the hollow body member is preferably greater than the screw pitch of the screw threading between hollow compression sleeve and the intermediate part of the hollow body member. Hereby, the screw threading of the engagement area forces the screw threading of the compression sleeve to “climb” onto the screw threading of the intermediate part, due to the tapering surfaces, thereby causing the intermediate part to be compressed inwardly. 
     By means of the screw threading between the hollow compression sleeve and the hollow body member, a relatively small movement in the rotational direction is transferred to a relatively small axial movement, which works on the entire engagement area, and provides engagement over a relatively large axial extension of the coupling device. 
     Preferably, the compression sleeve is lockable on the hollow body when it arrives at an engaged and coupled state. This locking may e.g. be achieved by a snap locking arrangement which automatically locks the parts at a certain point of engagement. 
     The hollow body member is further preferably provided with a shoulder forming a positive stop for the hollow compression sleeve, prohibiting continued engagement between the hollow compression sleeve and the hollow body member at a certain point, and thereby providing a maximum for the reduction of the inward diameter of the intermediate part. Hereby, the risk of over-tightening the connection, which could possibly lead to damage of the medical tubing, is prevented. 
     The coupling device also preferably further comprises a tube of a flexible material, arranged in the hollow body member in the area of the intermediate part, whereby the tube is situated between the intermediate part of the body member and a medical tubing end inserted into the coupling device. Hereby, the friction between the medical tubing and the coupling device is improved, and also, it becomes easier to obtain a tight and leak proof connection. 
     These and other aspects of the inventive concept will be apparent from and elicited with reference to the embodiments described hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       By way of example embodiments of the invention will now be described with reference to the accompanying drawings in which: 
         FIG. 1  is a cross-sectional view of a first embodiment of a coupling device according to the invention in an unconnected disposition; 
         FIG. 2  is a side-view of the coupling device of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of the coupling device of  FIG. 1 , in a connected but non-tightened state; 
         FIG. 4  is a cross-sectional view of the coupling device of  FIG. 1 , in a connected and tightened state; 
         FIG. 5  is a cross-sectional view of a coupling device according to a second embodiment of the invention, in a connected but non-tightened state; and 
         FIG. 6  is a cross-sectional view of the coupling device of  FIG. 5 , in a connected and tightened state. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     In the following detailed description preferred embodiments of the invention will be described. However, it is to be understood that features of the different embodiments are exchangeable between the embodiments and may be combined in different ways, unless anything else is specifically indicated. It may also be noted that, for the sake of clarity, the dimensions of certain components illustrated in the drawings may differ from the corresponding dimensions in real-life implementations of the invention, e.g. the length of the coupling device. 
     A coupling device according to a first embodiment will first be described with reference to  FIGS. 1-4 . This coupling device  1  for releasable connection of a medical tubing  2 , with no coupling parts being inserted into the lumen of the medical tubing comprises a hollow body member  110 , compression means in the form of a compression sleeve  120 , and a flexible inside tube  130 . On the other end, the coupling device is connectable to medical tubing  3 , medical devices, or the like. 
     The hollow body member  110  comprises a first end  111  for receiving a medical tubing end and an opposite second end  112 , for conveying an input/output to the medical tubing. At least part of the hollow body member between the first and second end forms an intermediate part  113 . The flexible inside tube  130 , preferably made of a less rigid material than the hollow body member  120 , is preferably arranged inside the inside bore of the hollow body member in such a way that it extends over the entire intermediate part, and is preferably attached to the inside of the hollow body member at least at the ends of the tube. 
     The intermediate part  113  of this embodiment comprises a plurality of separated fingers  114 . The separation distance between the fingers makes it easy for the intermediate part to contract and expand. The separations are preferably open holes, but may also be filled with elastic material or the like (not shown). 
     The separated fingers each comprises a number of outwardly protruding parts  115 , each having a surface tapering in the direction towards the first end of the hollow body member. The protruding parts  115  are arranged in a path forming a screw threading along at least a substantial part of the intermediate part  113 . 
     Between the intermediate part  113  and the second end  112 , an engagement area is formed, and provided with a protruding screw thread  116 . Between the engagement area and the second end  112 , a shoulder portion  117  is further provided. 
     The second end  112  of the hollow body member may be provided with a protruding screw thread  118  or the like for attachment to conventional medical tubing  3  and/or medical devices. For example, the second end may form a so-called “Luer lock” connection. Such connections are per se well known in the art. 
     The intermediate part  113  is compressible into a contracted state, in which the inward diameter, facing the medical tubing, is reduced. This contraction is in this embodiment achieved by means of a compression sleeve  120 . The compression sleeve forms a collar around part of the hollow body member, and engages with various parts of the hollow body member, as is now to be disclosed in more detail. 
     The compression sleeve  120  comprises a first end  121  which in use is moved over the first end  111  of the hollow body member, and an opposite second end  122 . The inner surface of the internal bore of the compression sleeve is provided with a first screw threading  123 , in the vicinity of the second end  122 , and a second screw threading  124 , in the vicinity of the first end  121 . The first screw threading is provided with tapering surface areas, in correspondence with the tapering of the protruding parts  115  of the intermediate part  113  of the hollow body member  110 . 
     The second screw threading  124  of the compression sleeve is arranged to engage with the screw threading  116  of the hollow body member, and the first screw threading  123  of the compression sleeve is arranged to engage with the screw threading formed by the protruding parts  115  of the hollow body member. The screw pitch of the screw threading  124 / 116  and the screw threading  123 / 115  is different, and preferably the pitch of the screw threading  124 / 116  is greater than the pitch of the screw threading  123 / 115 . 
     In use, the compression sleeve  120  is arranged in a connected position over the hollow body member  110 , and the medical tubing end is inserted through the first end of the hollow body member, and inserted to such an extent that it extends through the intermediate part  113 . This state is illustrated in  FIG. 3 . 
     Thereafter, the connection between the compression sleeve  120  and the hollow body member  110  is tightened by a relative rotation of the parts. Hereby, the compression sleeve and the hollow body engages primarily in the screw threading  124 / 116 , which forces the screw threading  123  of the compression sleeve to “climb” onto the screw threading  115  of the intermediate part, due to the tapering surfaces, thereby causing the intermediate part to be compressed inwardly. Such a tightened state is illustrated in  FIG. 4 . In this state, the medical tubing end is connected to the coupling device, and is held firmly in place, without and damage of the medical tubing or the like. 
     In the tightened position, the shoulder  117  of the hollow body member provides a positive stop in combination with the leading edge  121  of the compression sleeve. Hereby, over-tightening of the connection is prohibited. 
     A second embodiment will now be discussed. The coupling device of this embodiment generally resembles the first embodiment discussed in the foregoing, but with the following differences related to the intermediate part of the hollow body member. 
     In this embodiment, the intermediate part  113 ′ comprises, instead of a plurality of protruding parts, each having a tapering surface, only one conically tapering surface  115 ′, extending over more or less the entire intermediate part  113 ′. The compression sleeve is provided with a corresponding single conically tapering surface  123 ′. If an elastic material is used, the intermediate part  113 ′ need not be arranged in separated fingers, as in the previously discussed embodiment. However, it is naturally feasible to provide such separate fingers also in this embodiment, whereby the conically tapering part would then consequently be divided into a corresponding number of segments. 
     In this embodiment, engagement of the compression sleeve and the hollow body member, and subsequent compression and contraction of the intermediate part  113 ′ occurs in a similar way as discussed above in relation to the first embodiment.  FIG. 5  illustrates a non-tightened state, whereas  FIG. 6  illustrates a tightened state. 
     The hollow body member and the compression sleeve may e.g. be injection molded of a plastic material. These parts are preferably made of a relatively rigid material. The flexible tube may be a piece of ordinary medical tubing, and is preferably made of a somewhat less rigid material. The flexible tube may be connected to the hollow body by means of adhesion, welding or the like. Alternatively, the flexible tube may be integrated with the hollow body. For example, it is possible to produce the hollow body and the flexible tube in a single manufacturing step, by means of two component injection molding or the like. 
     The invention has now been discussed in relation to different embodiments. However, it should be appreciated by those versed in the art that several further alternatives are possible. For example, the features of the different embodiments discussed above may naturally be combined in many other ways. 
     It is further possible to use a friction fit or the like instead of a screw threading for providing the tightening between the hollow body member and the compression sleeve. Still further, the second end of the hollow body member may be formed in a number of ways, and e.g. being integrated in a medical device or the like. It will be appreciated by those versed in the art that several such alternatives similar to those described above could be used without departing from the spirit of the invention, and all such modifications should be regarded as a part of the present invention, as defined in the appended claims.