Abstract:
A tubing including an overmold is connected to a fitting by welding the overmold to the fitting. Methods for doing the same are also provided. Also provided are methods for forming an overmold on a tubing or on a tubing and fitting assembly.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based upon and claims priority to U.S. Provisional Application Ser. No. 62/149,031, filed on Apr. 17, 2015, entitled “MODULAR MOLDING”, the contents of which are fully incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Fluid transfer assemblies for use in transporting medical substances, as well as fluid use in formulating pharmaceuticals, include connecting portions which connect tubular portions. The connecting portions may be “T” fittings, crosses, or just linear fittings for connecting two tubes together. Other connection types include those by which tubular portions are connected to another functional component of the fluid transfer assembly, such as a filter. Typically, these fluid transfer assemblies are formed via mechanical connections that most often comprise a hose barb connector. The hose or tubing is fitted over the hose barb connector and a cable tie, or other mean of mechanically securing the tube to the connector, is then affixed over the tubing and hose barb. These mechanical connections serve primarily to lock the tubing in place and prevent it from sliding from the hose barb connector, however the primary seal is provided via the hose barb and tubing interface. In other fluid transfer assemblies, the connections are formed via a process commonly known as overmolding. Tubing to be connected is placed in a mold with the internal bore thereof typically supported via a removable internal component, after which a molding process is completed to form the overmold, and the internal support typically removed. The challenges associated with this is approach is that the internal support limits the applications is can be applied to. It is also often difficult to precisely align the tubes in the molding equipment to properly allow for the formation of the overmolded piece, and the operation in general limits fabrication flexibility. 
       SUMMARY OF THE INVENTION 
       [0003]    In an example embodiment a method of attaching a tubing to a fitting is provided. The method includes forming an overmold over an end of the tubing, and welding the overmold to an end of the fitting allowing for flow through the tubing and fitting. In another example embodiment, the method further includes forming another overmold over another tubing end, and welding the another overmold to another end of the fitting allowing for flow through the tubing, the fitting and the another tubing. In one example embodiment, forming the overmold includes forming the overmold having a first section surrounding an end portion of the tubing and a second section extending from the first section and extending beyond the end portion of the tubing in a direction opposite the tubing, and welding includes welding the second section to the fitting end. In a further example embodiment, the fitting end includes a fitting end surface and the second section includes a second section end surface, and welding includes abutting the second section end surface to the fitting end surface. In yet a further example embodiment, the second section defines an inner surface for contacting the fluid flow, and forming the overmold includes forming the inner surface to have a first portion having a first diameter and a second portion extending from the first portion to the second section end surface having a second diameter greater than the first diameter. In another example embodiment, the fitting includes an inner surface for contacting the fluid flow, the inner surface having a first portion having a first diameter and a second portion extending from the first portion to the fitting end surface and having a second diameter greater than the fitting inner surface first diameter. In yet another example embodiment, welding includes filling at least a portion of the second portions of the overmold and the fitting with molten material molten during the welding. In a further example embodiment, the tubing includes an inner surface having a diameter for contacting the fluid flow, and the tubing inner surface diameter is the same as the second section inner surface first diameter and the fitting inner surface first diameter. In yet a further example embodiment, the fitting end includes a recess and the overmold includes a projection extending transversely from an annular surface of the overmold, and the method includes inserting the projection into the recess prior to welding. In one example embodiment, the recess includes a first shallower portion and a second deeper portion extending radially outward form the first shallower portion, and inserting the projection, includes inserting the projection to abut the first shallower portion. In another example embodiment, the overmold is formed from at least one of a thermoplastic elastomer or a polypropylene, the fitting is made from at least one of a polypropylene or polyethylene, and the tubing is made from a thermoplastic elastomer. 
         [0004]    In a further example embodiment, a tubing assembly is provided. The tubing assembly includes a first tubing including a first overmold formed over an end of the first tubing and a fitting including a first end. The first overmold is welded to the first end allowing for a flow through the tubing to the fitting. In yet another example embodiment, the tubing assembly also includes a second tubing including a second overmold formed over an end of the second tubing, and the fitting includes a second end, and the second overmold is welded to the second end allowing for a flow through the tubing, the fitting and the second tubing. In a further example embodiment, the first overmold includes a first section surrounding an end portion of the tubing and a second section extending from the first section and extending beyond the end portion of the tubing in a direction opposite the tubing, and wherein the second section is welded to the first end of the fitting. In yet another example embodiment, a recess is defined in the first end and wherein the first overmold includes a projection received in the recess. In one example embodiment, the projection extends transversely from an annular surface surrounding the projection and the recess includes a first shallower portion and second deeper portion radially outward from the first shallower portion, and wherein the projection abuts the first shallower portion. In a further example embodiment, the first end of the fitting includes an annular portion radially outward of the recess, the recess is defined within the annular portion, and when the projection is abutting the recess first shallower portion, the fitting first end annular portion is spaced apart from the annular surface of the overmold. In yet a further example embodiment, the fitting is part of, or is coupled to, an encapsulated filter for providing fluid flow to such filter. In one example embodiment, the fitting is part of, or is coupled to, a component of a fluid transfer assembly selected from the group of components consisting essentially of filters, sensing components, pressure gauges, and biocontainers. In another example embodiment, the overmold is formed from at least one of a thermoplastic elastomer or a polypropylene, the fitting is made from at least one of a polypropylene or polyethylene, and the tubing is made from a thermoplastic elastomer. 
         [0005]    In yet another example embodiment, a tubing assembly is provided including a tubing including a first overmold formed over an end of the first tubing, and a fitting including a first end, wherein the overmold is thermally bonded to the first end and the tubing. In a further example embodiment, the overmold is formed from at least one of a thermoplastic elastomer or a polypropylene, the fitting is made from at least one of a polypropylene or polyethylene, and the tubing is made from a thermoplastic elastomer. 
         [0006]    In yet a further example embodiment, a method for forming tubing assembly is provided. The method includes selecting a fitting having first end and a second end, a first flange closer to the first end than the second end, a second flange closer to the second end than the first end, and a locating feature, inserting the first end into a first tubing until the first tubing abuts the first flange, inserting the second end into a second tubing until the second tubing abuts the second flange, placing the fitting with tubings into a mold aligning the locating feature with a locating feature within the mold, molding a first overmold over the first tubing and over the fitting, and molding a second overmold over the second tubing and over the fitting. In another example embodiment, the first and second flanges are different portions of the same flange. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1A  is a plan view of an example embodiment fitting with projection. 
           [0008]      FIG. 1B  is a top view of the fitting shown in  FIG. 1A . 
           [0009]      FIG. 1C  is a bottom cross-sectional view of the fitting shown in  FIG. 1A , taken along arrows  1 C- 1 C. 
           [0010]      FIG. 1D  is plan cross-sectional view of the fitting shown in  FIG. 1A , taken along arrows  1 D- 1 D. 
           [0011]      FIG. 2  is a plan cross-sectional view of a tubing assembly incorporating the fitting shown in  FIG. 1A . 
           [0012]      FIG. 3  is a perspective view of a mold used to form overmolds in the tubing assembly shown in  FIG. 2 . 
           [0013]      FIGS. 4A and 4B  are cross-sectional views rotated 90 degrees, respectively, of a tubing assembly connecting a smaller diameter tubing to a larger diameter tubing. 
           [0014]      FIGS. 5A and 5B  are top and plan views, respectively, of a fitting used in the tubing assembly shown in  FIGS. 4A and 4B . 
           [0015]      FIGS. 5C and 5D  are cross-sectional views rotated 90 degrees, respectively, of the fitting shown in  FIGS. 5A and 5B , taken along arrows  5 C- 5 C and  5 D- 5 D, respectively. 
           [0016]      FIG. 6  is a cross-sectional view of an example embodiment tubing assembly prior to welding. 
           [0017]      FIG. 7  is a cross-sectional view of the tubing assembly shown in  FIG. 7  after welding. 
           [0018]      FIG. 8  is a cross-sectional view of another example embodiment tubing assembly prior to welding. 
           [0019]      FIG. 9  is a cross-sectional view of the tubing assembly shown in  FIG. 8  after welding. 
           [0020]      FIG. 10A  is a perspective view of another example embodiment overmold fitting assembly where the overmold is thermally welded to the fitting. 
           [0021]      FIGS. 10B, 10C, and 10D  are partial cross-sectional views of the example embodiment overmold fitting combination shown  FIG. 10A .  FIG. 10B  is an assembly view.  FIG. 10C  is a partial exploded view of the embodiment shown in  FIG. 10B .  FIG. 10D  is an assembled view. 
           [0022]      FIGS. 11A and 11B  are partial cross-sectional views of another example embodiment assembly, where  FIG. 11A  is an exploded view and  FIG. 11B  is an assembled view. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    In a first example embodiment, the present disclosure is related to a fluid transfer assembly formed by connecting three tubes or conduits together using a “T” connector or fitting (individually or collectively “fitting”). However, it should be understood that the disclosure is not limited assemblies using just using “T” fittings for connecting three tubes. In other examples, a linear fitting can be used to connect two tubes, or cross fittings may be used to connect four tubes, or other multiple connector fittings for connecting multiple tubes. In an example embodiment shown in  FIGS. 1A, 1B, 1C and 1D , a “T” fitting  10  (the “fitting”) is used. The fitting includes three barbed ends  12 ,  14 ,  16 , and also, a locating feature  18 , such as a projection that extends from a body  20  of the fitting. The projection does not extend into the fluid flow path  22  of the fitting, as can be seen in  FIG. 1C . Each barb end has an outer surface  24  tapering from a larger diameter  26  to a smaller diameter  28  toward or at its corresponding end  30 . It should be noted that fittings can also function, in an example embodiment, without the tapering outer surface, specifically, without a barb. In other words, in some embodiments, a barb is not necessary. 
         [0024]    Flanges  32 ,  34  or gussets are attached to the fitting. In an example embodiment, a first flange  34  is attached along the linear portion of the fitting, and two opposite “L” shaped flanges  32  are attached between the horizontal and vertical portions of the fitting. In an example embodiment, the flanges  32 ,  34  are plate like members. The flanges form stops and as such may have shapes other than plate like. 
         [0025]    To assemble the assembly, a tube  36 ,  38 ,  40  is placed over its corresponding barbed end until an end  37 ,  39 ,  41  of the tube abuts against the ends of flanges  32  and  34 , as shown in  FIG. 2 . The connection is then placed into injection molding equipment mold  42 , such that the projection  18  is received in a complementary depression  44  in the mold ( FIG. 3 ). The projection aligns the fitting within the mold such when an overmold  48  is formed in the mold, it will extend a desired amount over each tube end and corresponding fitting end, as for example shown in  FIG. 2 . Thus, each type of fitting can be aligned precisely in the mold to produce the right sized overmold. In this regarding, standard fittings having the appropriate locating feature can be used to repeatedly produce the same overmold having the same dimensions over the same portions of all the tubes being connected. 
         [0026]    The overmold is formed by injection molding. A heated material is injected into the mold to form the overmold using methods known in the art. In one example embodiment, the material may be a thermoplastic elastomer (TPE) or a polypropylene. 
         [0027]    In an example embodiment, the rigid fitting may also be made of polypropylene or polyethylene. In another example embodiment, the fitting may be made from TPE. In an example embodiment, the tubes may be made from a thermoplastic elastomer (TPE) material. During the overmolding process, heat from the injected material which forms the overmold is sufficient to create a permanent, or a significantly permanent, thermal bond between both the tubes and their respective overmolds, as well as the rigid fitting ends and their respective overmolds. The heat from the injected material is sufficient to at least partially melt at least an outer surface portion of the tubing and/or fitting, which together with the injected material form the thermal bond. This thermal bond allows the overmold to be the connector between the tube and fitting. Once the overmolding has taken place, the assembly  50  is removed from the mold and is ready to use and in an example embodiment with no further post processing. 
         [0028]    In an example embodiment, the fitting is formed with the flanges  32 ,  34  in place. In other words, the flanges are formed integrally with the fitting or may be formed by machining the outer surface of the fitting. In other example embodiments, the flanges may be separately formed and attached to the fitting as for example by bonding, such as adhesive boding or welding. Welding as used herein refers to known welding processes such as thermal welding processes which include, but are not limited to, hot plate welding, thermal impulse welding and induction heating. Other welding processes include ultrasonic welding and friction welding. The welding processes generate sufficient heat to melt the materials of the parts being welded at the location where the welding takes place. Other processes that generate heat to melt the materials of the parts being welded sufficiently for intermixing are also considered as welding processes. Thus, “welding” as used herein refers to all welding processes used to join plastics. 
         [0029]    In another example embodiment, a fitting  60  may be used to connect a larger diameter tube  62  with a smaller diameter tube  64  ( FIGS. 4A and 4B ). Again, a locating feature, such as a projection  68  extends from the fitting  60 . The fitting also includes opposite flanges  70  ( FIGS. 4A, 4B, 5A, 5B, 5C and 5D ). As before, the two diameter tubings are slid over their corresponding barbed ends  74 ,  76  of the fitting until they abut the flanges  70 . The fitting with tubing is then placed into the molding equipment mold, and the projection  68  is fitted within a corresponding depression within the mold, precisely aligning the fitting within the mold so as to allow for the overmold  80  to be formed at the precise locations and over a precise amount of the tubes  62 ,  64 . In other example embodiments, instead of a projection  18 ,  68  a depression is formed on the fitting and a corresponding projection is formed in the mold instead of the depression  48 . In this regard, the mold projection will be received in the fitting depression. 
         [0030]    In another example embodiment, an overmold  100  is overmolded at the end of each tubing  102 , as for example shown in  FIG. 6 , using well known methods. As before, the overmold may be formed from TPE or polyolefin, as for example polypropylene or polyethylene. The tubings may be made from a thermoplastic elastomer (TPE). Each overmold with attached tubing may then be welded to a rigid fitting  104 , as for example a polypropylene molded fitting  104 . In another example embodiment, the fitting  104  can be manufactured from a TPE material. The fitting  104  may be a “T” connector shown in  FIG. 6 . In another example embodiments, the connector may be a linear connector for connecting two tubings, or may be a cross connector or any other type of connectors for connecting multiple tubings together, or a member of connecting tubing to another functional component of the fluid transfer assembly, such as for example a filter, a pressure gauge, a sensing component, a biocontainer, etc. 
         [0031]    In the shown exemplary embodiment, each overmold  100  is molded over an end  106  of its corresponding tubing  102  using known methods such as injection molding. The overmold is bonded to its corresponding tubing and in exemplary embodiments, is thermally bonded to its corresponding tubing. In this regard each overmold  100  includes a larger diameter inner surface  108  and a smaller diameter inner surface  110  defining a shoulder  112  there between. The larger diameter outer surface  110  interfaces with the outer surface  114  of the tubing. The smaller diameter inner surface  110  in an example embodiment has the same diameter as the inner surface  116  of the tubing. While the diameters of the smaller diameter inner surface of the overmold and the diameter of the inner surface of the tubing in one embodiment are not the same, in an example embodiment they are preferred to be the same to allow for a smooth transition and thus flow between the two. Each end  118  of the fitting  104 , in an example embodiment, is complementary to the end  120  of an overmold  100 . In other words the diameter of the inner surface  122  of the fitting is the same as the diameter of the smaller diameter inner surface  110  of the fitting. Similarly the diameter of the outer surface  124  of the overmold proximate the end  120  is the same as the diameter of the outer surface  126  of the fitting end  120 . The overmold  100  with its attached corresponding tubing  102  is welded to the end  118  of the fitting. 
         [0032]    In an example embodiment, areas of relief  132 , are formed at the inner surface of the overmold extending to the end  120  and at the inner surface of the fitting extending to the end  118 . The relief sections are formed by increasing the inner surface diameter for a linear length to account for melt back during the welding process, such that when the complete joint is formed, a generally smooth inner surface is formed across the inner surface of the overmold and the inner surface of the fitting. In one example embodiment, the inner surface diameter is increased by up to half of the thickness  204  of the tubing wall for length up to half of the thickness  204  of the tubing wall to form the area of relief. The welding is accomplished using standard thermal processes creating thermal weld joints  134  and integral fluid paths  136  without requiring further post processing because of the area of relief, as shown in  FIG. 7 . 
         [0033]    In another example embodiment, the overmold can have a smaller diameter inner surface section  138  that tapers to a larger diameter section or end  140 , as for example shown in  FIGS. 8 and 9 . The larger section end  140  is complementary to a fitting  142  end  144 . The end  140  of the overmold is welded to the end  144  of the fitting allowing for a smaller diameter tubing  146  to be coupled to a larger diameter tubing  148  using a fitting  142 . The larger diameter tubing is connected to the fitting as described with the previous embodiment. In another example embodiment, a yet larger diameter tubing may be fitted with an overmold having an inner surface that decreases in diameter toward its end. In this regard the decreased diameter end is welded to the fitting allowing for an even larger diameter tubing to be connected to a larger diameter tubing  148 . 
         [0034]    In another example embodiment, the tubings with overmold are attached to a fitting  151  as shown in  FIGS. 10A, 10B, 10C, and 10D . In the example embodiments shown in  FIG. 10A , a cross fitting is used to couple four tubings (two larger diameter tubings  154  and two smaller diameter tubings  184 ). However, this example embodiment may be used to connect tubings of the same or different diameters. In the shown example embodiments, each of the overmolds  150  includes a projection  152  defined opposite the tubings  154 ,  184 . The projection is defined by creating a depression defining a surface, such as an annular surface  153 . A recess  156  is defined in the fitting  151  to receive the projection  152 . In the shown example embodiment, the overmold diameter  158  of the recess  156  is greater than the outer diameter  160  of the projection  152 . In the shown example embodiment, the recess  156  includes an outer deeper portion  162  and a shallow inner portion  164 . The shallow inner portion has a diameter  168  that corresponds to the outer diameter  160  of the projection. In this regard, when the projection is inserted into the recess, the end surface  170  of the projection is aligned to abut against the shallow inner portion  164  end surface  163  of the recess. Moreover, the projection has a length  172  that is slightly greater than the length  174  of the outer deeper portion  162  of the recess  156 . In this regard, when the overmold projection end surface  170  abuts the recess end surface  163 , a gap  165  is defined between an edge end surface  174  of the fitting and the end surface  153  of the overmold. Once the overmold abuts the fitting, a relief area  167  is defined between the end surface  153  and the end surface  169  of the outer deeper portion of the recess. In this regard, during thermal welding, any overage of the welded material is received within the gap  165  and the relief area  167 , thus preventing or minimizing overflow of the welded material. 
         [0035]    In another example embodiment, instead of the outer recess portion  162  being deeper than the recess shallow inner portion  164  of the recess  156 , it may have the same depth or may be shallower. In yet another example embodiment, the recess may extend all the way across the entire fitting such that an annular portion  176  is not defined around the recess  156 . An annular groove  180  may be defined on the outer surface of the overmold allowing for handling of the overmold and for positioning onto the fitting. 
         [0036]    As shown in  FIGS. 10B and 10D , an overmold having the same interface feature, such as an overmold  182 , may be used to connect a smaller diameter tubing  184  to the fitting. It should be understood that in other example embodiments, the end geometries of the overmold and fitting may be reversed such that the fitting end fits into the overmold. In other example embodiments, the end geometry of the fitting may be formed as part of an overmold at the end of the fitting. In other words, the fitting may have multiple sections or parts. 
         [0037]    In the example embodiment shown in  FIG. 6 , the overmold overlaps the tubing along a longitudinal distance  200  that is greater than the wall thickness  204  of the tubing. In an example embodiment, the distance  200  is at or about four times the wall thickness  204 . The overall length  206  of the overmold, in an example embodiment, is also greater than the tubing wall thickness  204 . In one example embodiment, the overall length  206  of the overmold is equal to, or about equal to, eight times the wall thickness  204 . However, it can range to a length longer or shorter than that. In an example embodiment shown in  FIG. 10C , the overmold extends over the tubing by a length  210  greater than the thickness  212  of the tubing wall. In one example embodiment, it extends over the tubing wall by four times or about four times the thickness of the tubing wall. In an example embodiment, the projection  152  extends axially from the surface  153  by a distance (length)  172  that is about equal to, or greater than, 0.25 times the thickness  216  of the projection  152 . In an example embodiment, the length  172  of the projection  152  is about equal to the thickness  216  of the projection, plus about 0.030 inches. In the shown example embodiment, the thickness  218  of the overmold section extending over the tubing is about equal to, or is equal to, the tubing wall thickness  212  of the tubing. In one example embodiment, the thickness of the overmold is about equal to, or greater than, at least half the thickness of the tubing wall  212 . In another example embodiment, the deeper portion  162  of the recess  156  extends along a radial distance  220  that is at least about 0.25 times the thickness  216  of the projection  152 . In an example embodiment, it is about 0.75 times the thickness  216  of the projection. 
         [0038]    In another example embodiment, the tubing  102  with overmold  100 , as for example shown in  FIGS. 6, 7A, and 9 , or a tubing  154  with overmold  150 , as for example shown in  FIGS. 10B, 10C, and 10D , is thermally welded to a fitting for receiving fluids to be processed through an encapsulated filter  302 , as for example shown in  FIGS. 11A and 11B . In other example embodiments, instead of a filter, the fitting is connected to, or is part of, another component of a fluid transfer assembly, such as for example a sensing component, a pressure gauge, or a biocontainer. The overmold is connected to a fitting  300  by thermal welding as described in relation to  FIGS. 6 to 10D . The end fitting  300  receives fluid to be processed through an encapsulated filter  302 . The end fitting and encapsulated filter (or other device) may form a cartridge  310 , as for example shown in  FIGS. 11A and 11B . 
         [0039]    In example embodiments disclosed in  FIGS. 6 to 11B , the overmold material may be formed from a TPE or a polypropylene, the fitting is formed from the fitting polypropylene, polyethylene, or TPE, and the tubings may be made from a TPE. In other example embodiments, other material that allow for thermal welding and/or thermal bonding may be used. 
         [0040]    With the example embodiments shown in  FIGS. 6 to 11B , specific lengths of standard tubing sizes having specific inner surface diameters and outer diameters may be formed with an overmold and stored, and then may be welded as necessary to a fitting without the need of having to form an overmold over the connected tubing and fitting. In example embodiments, connectors or fittings may also be formed by an injection molding process. 
         [0041]    In another example embodiment, one overmold  100  extending from one tubing may be directly welded to another overmold  100  extending from another tubing to connect such two tubings together without the use of a connector or fitting. 
         [0042]    While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. The invention is also defined in the following claims.