[0001]    Needleless access port valves are generally discussed herein with particular discussions extended to needleless access port valves comprising a piston comprising an integrated gilled sheath. 
       BACKGROUND 
       [0002]    Needleless access port valves are widely used in the medical industry for accessing an IV line and/or the internals of a patient or subject. Generally speaking, prior art valves utilize a housing in combination with a moveable internal plug or piston to control the flow of fluid through a valve. The plug or piston may be moved by a syringe or a medical implement to open the inlet of the valve for accessing the interior cavity of the valve. When a fluid is delivered through the valve, fluid flow typically flows around the outside of the plug or piston in the direction towards the outlet. Upon removal of the syringe or medical implement, the plug or piston returns to its original position, either un-aided or aided by a biasing means, such as a spring or a diaphragm. 
         [0003]    In some prior art valves, when the syringe or medical implement pushes the plug or piston, the plug or piston is pierced by an internal piercing device, such as a spike. The spike typically incorporates one or more fluid channels for fluid flow flowing through the pierced piston and then through the fluid channels in the spike. In yet other prior art valves, a self-flushing or positive flush feature is incorporated to push residual fluids confined inside the interior cavity of the valve to flow out the outlet when the syringe or medical implement is removed. 
         [0004]    While prior art needleless access port valves are viable options for their intended applications, there remains a need for alternative needleless access port valves. 
       SUMMARY 
       [0005]    The present invention may be implemented by providing a needleless injection port valve comprising a valve housing defining an interior cavity having an inlet and an outlet, a piston comprising a core and a sheath positioned in the interior cavity of the housing by securing a perimeter section of the sheath in a bore proximate two mating surfaces on the valve housing; and wherein the sheath comprises a plurality of seals each comprising resilient surface to resilient surface contact. 
         [0006]    In accordance with other aspects of the present invention, there is provided a needleless injection port valve comprising a valve housing defining an interior cavity and a piston comprising a core and a sheath surrounding, at least in part, the core positioned in the interior cavity of the housing; the housing comprises a inlet section comprising an inlet opening, an outlet section comprising an outlet opening, and a body section attached to the inlet section and the outlet section; the body section having a body upper section, a body center section, and a body lower section all having a respective cross-sectional dimension, and wherein the cross-sectional dimension of the body center section is less than the cross-sectional dimensions of the body upper section and body lower section along a cross-sectional side view of the valve. 
         [0007]    In yet other aspects of the present invention, there is provided a needleless injection port valve comprising a valve housing defining an interior cavity and a piston comprising a core and a sheath attached to a lower section of the core and extending proximally along at least a portion of the core; the piston being positioned in the interior cavity by wedging a perimeter section of the sheath in between a shoulder defined by an inlet nozzle section and a shoulder defined by an upper housing chamber; wherein the piston comprises at least one gill located on the sheath; said gill having a first configuration corresponding to a first valve position in which a first resilient surface contacts a second resilient surface and having a second configuration corresponding to a second valve position in which the first resilient surface is spaced apart from the second resilient surface. 
         [0008]    In yet another aspect of the present invention, there is provided a plurality of ribs connected to a core and a sheath for increasing the returning force in returning the core from a used position to a ready position. 
         [0009]    In still yet another aspect of the present invention, there is provided separate threaded collar mechanically coupled to an outlet for providing a threaded male Luer connector. 
         [0010]    In a further aspect of the present invention, there is provided a body section over-molded to an upper valve body chamber and a lower valve body chamber defining a valve cavity. 
         [0011]    Other aspects and variations of the valve assemblies summarized above are also contemplated and will be more fully understood when considered with respect to the following disclosure. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    These and other features and advantages of the present invention will become appreciated as the same become better understood with reference to the specification, claims and appended drawings wherein: 
           [0013]      FIG. 1  is a semi-schematic perspective view of an injection port valve provided in accordance with aspects of the present invention; 
           [0014]      FIG. 2  is a semi-schematic top view of the valve of  FIG. 1 ; 
           [0015]      FIG. 3  is a semi-schematic cross-sectional side view of the valve of  FIG. 2  taken along line A-A; 
           [0016]      FIG. 4  is a semi-schematic cross-sectional side view of the valve of  FIG. 3  taken along line B-B; 
           [0017]      FIG. 5  is a semi-schematic perspective view of a piston provided in accordance with aspects of the present invention; 
           [0018]      FIG. 6  is a semi-schematic perspective view of an injection port valve provided in accordance with aspects of the present invention in a used position; 
           [0019]      FIG. 7  is a semi-schematic top view of the valve of  FIG. 6 ; 
           [0020]      FIG. 8  is a semi-schematic cross-sectional side view of the valve of  FIG. 7  taken along line C-C; 
           [0021]      FIG. 9  is a semi-schematic cross-sectional side view of the valve of  FIG. 8  taken along line D-D; and 
           [0022]      FIG. 10  is a semi-schematic perspective view of the piston of  FIG. 5  in a used configuration. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    The detailed description set forth below in connection with the appended drawings is intended as a description of the presently preferred embodiments of needleless access port valves or backcheck valves (herein “valves”) provided in accordance with aspects of the present invention and is not intended to represent the only forms in which the present invention may be constructed or utilized. The description sets forth the features and the steps for constructing and using the valves of the present invention in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and structures may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention. As denoted elsewhere herein, like element numbers are intended to indicate like or similar elements or features. 
         [0024]    Turning now to  FIG. 1 , a semi-schematic perspective view of a valve provided in accordance with aspects of the present invention is shown, which is generally designated  10 . In one exemplary embodiment, the valve  10  comprises a valve housing  12  comprising an inlet  14  and an outlet  16 . The inlet  14  is adapted to receive a first medical implement (not shown), such as a syringe, an IV tubing adapter, and the like, for delivering fluid from the first medical implement through the valve  10  and out the outlet  14 , which is adapted to connect to a second medical implement, such as a tubing or a catheter assembly, for delivering the same to a patient or subject. In one exemplary embodiment, the inlet and the outlet both incorporate a standard luer taper. 
         [0025]    The valve  10  is shown in a first or closed position ( FIG. 1 ) having a piston  18  blocking the opening  20  defined by an inlet nozzle  22 . As further discussed below, when the piston  18  is in the first position, a seal located on the piston  18  seals against an interior surface of the inlet nozzle  22  to close fluid communication between the inlet  14  and the outlet  16 . In one exemplary embodiment, the inlet  14  comprises a female luer slip and an inlet lip  24  having a generally ring shaped structure. Alternatively, the inlet  14  may incorporate luer threads without deviating from the spirit and scope of the present invention. 
         [0026]    Also shown in  FIG. 1  is an inlet shoulder  26 , a valve body  28 , and a threaded collar  30  comprising a plurality of ridges  31 , which surrounds the outlet nozzle  44  ( FIG. 3 ). As further discussed below, the valve body  28  comprises an upper valve body section  32 , a middle valve body section  34 , and a lower valve body section  36  and wherein the middle valve body section  34  comprises a cross-sectional dimension that is less than the cross-sectional dimensions of the upper and the lower valve body sections  32 ,  36 . In one exemplary embodiment, the valve body  28  is integrally formed with two creases  38  defining two apexes ( FIG. 2 ), which resembles a partially crushed cylindrical tube having different cross-sectional dimensions along the length of the tube (See, e.g.,  FIG. 3 ). In one exemplary embodiment, the valve body  28  is made from a rigid or semi-rigid plastic of a semi-crystalline polymer type, such as polycarbonate, polypropylene, polyethylene, and nylon and more preferably from an elastomeric plastic of a thermoplastic elastomer (TPE) type such as the copolyamide (COPA) family of thermoplastic elastomers. In a preferred embodiment, the COPA is copolyamide thermoplastic elastomer having a commercial trade name PEBAX®. However, other TPEs may also be used to make the valve body  28 , including thermoplastic polyurethanes (TPUs), styrenic thermoplastic elastomers, thermoplastic polyolefins (TPOs), copolyesters (COPEs), and thermoplastic vulcanizate elastomeric alloys (TPVs). Optionally, the TPEs may be cross-linked either chemically or by irradiation to alter their characteristics. 
         [0027]      FIG. 2  is a top view of the valve  10  of  FIG. 1 . The piston  18  is shown occupying the opening  20  of the inlet nozzle  22  and occluding the opening from fluid flow when in the first position. The two creases  38  and part of the middle body section  34  are also shown, projecting beyond the periphery of the outlet collar  30 . 
         [0028]      FIG. 3  is a cross-sectional side view of the valve of  FIG. 2  taken along line A-A. In one exemplary embodiment, the valve housing  12  comprises an upper housing chamber  40  coupled to a body section  28  and to a lower housing chamber  42 , which comprises an outlet nozzle  44  comprising an outlet opening  45 . In a preferred embodiment, the body section  28  is over-molded to the upper and lower housing chambers  40 ,  42 , which are preferably made from a hard thermoplastic, such as, for example, polycarbonate, ABS, or acrylic. Alternatively, the parts may be glued together rather than over-molded. The upper housing chamber  40  comprises a perimeter rim  46  and a mating seat  48  for matingly engaging a piston flange  50  on the plunger  18 . In one exemplary embodiment, the mating seat  48  comprises an inner rim  52  and together with the perimeter rim  46  define a groove  54 . The piston flange  50  is positioned in the groove  54  and is secured thereto by fixing the inlet shoulder  26  to the perimeter rim  46 . In one embodiment, the shoulder  26  and the rim  46  are welded, using a laser or high frequency welding, to maintain a more permanent connection. Alternatively, glue or adhesive may be used to bond the shoulder  26  and the rim  46  together to retain the piston flange therein. 
         [0029]    The upper housing chamber  40  comprises an interior surface defining a bore  56  that tapers slightly inwardly in the distal direction and an exterior wall  57  that also tapers inwardly in the distal direction. In a preferred embodiment, the slope of the exterior wall  57  is greater than the slope of the interior wall  56  so that the upper housing chamber  40  has a greater wall thickness near its proximal end than at its distal end. 
         [0030]    The body section  28 , in the cross-sectional side view of  FIG. 3 , comprises an hourglass configuration with the upper valve body section  32  and the lower valve body section  36  being larger than the middle valve body section  34 . Exteriorly, the lower valve body section  36  tapers outwardly as it extends distally to mate with a similarly outwardly tapered hub section  58  of the lower housing chamber  42 . Interiorly, the wall surface of the tapered hub section  58  tapers inwardly as it extends distally to communicate with a generally cylindrical lumen of the outlet nozzle  44 . 
         [0031]    Exteriorly, the lower housing chamber  42  comprises an upper shoulder section  60  and a lower shoulder section  62  defining a groove  64  therebetween. The groove  64  functions as a female detent for mating engaging with a male detent or proximal cylindrical opening  66  of the threaded collar  30 . A tapered ramp just distal of the lower shoulder section  62  may be incorporated to facilitate insertion of the outlet nozzle  44  into the proximal opening  66  of the collar  30  and for the opening to slide over and engage the female detent  64 . The collar  30 , having interior threads  68 , may be made from a hard plastic material, such as, for example, polycarbonate or ABS. 
         [0032]      FIG. 4  is a cross-sectional side view of the valve of  FIG. 3  taken along line B-B. The upper and lower housing chambers  40 ,  42  are shown with exterior wall surfaces  57 ,  70  that are generally constant as measured from a center axis defined along a lengthwise direction of the valve  10 . However, the interior wall surfaces  56 ,  59  of the upper and lower housing chambers  40 ,  42  maintain similar taper as that shown in the cross-sectional side view of  FIG. 3 , i.e., they are symmetrical. The interior wall surface  72  of the body section  28  is also generally constant as measured from the center axis defined by the lengthwise direction of the valve. 
         [0033]    In one exemplary embodiment, the piston  18  comprises an elongated core  74  and a sheath  76  comprising a piston flange  50 . In a preferred embodiment, the elongated core  74  and the sheath  76  are integrally formed from a medical grade silicone material. However, other rubber materials may be used without deviating from the spirit and scope of the present invention, including polyisoprene. In one exemplary embodiment, the piston  18  incorporates a self-lubricating material for facilitating movement of the core  74  from a first position to a second position and vice versa. The self-lubricating material reduces friction between the interface of the core  74  and sheath  86  and the interior surface of the inlet nozzle  22 . In one exemplary embodiment, the self-lubricating material is a two-part self-lube liquid silicone rubber. The two-part self-lube silicone rubber is commercially available from Nusil Silicone Technology of Santa Barbara, Calif. Various aspects of the self-lube liquid silicone rubber are described in U.S. Pat. No. 6,871,838, filed Apr. 3, 2003, the contents of which are expressly incorporated herein by reference as if set forth in full. 
         [0034]    The core  74  comprises a body section  77  comprising an outer diameter and a head section  78  comprising an outer perimeter rim  80  having an outer diameter larger than the diameter of the body section  77 . In a preferred embodiment, the diameter of the outer perimeter rim  80  is also larger than the inner diameter of the inlet nozzle  22  for sealing against the interior surface of the inlet nozzle to seal the valve  10  when the piston is in the closed position. In one exemplary embodiment, a 0.5 mil to about a 2.5-mil total interference fit is incorporated between the outer perimeter rim  80  and the interior diameter of the inlet nozzle  22 . The core  74  comprises a tapered lower section  82  terminating in a rounded distal end point  84  ( FIG. 4 ). The tapered lower section  82  provides clearance between the core  74  and the interior surface  56  of the upper housing chamber  40  so that the plunger may move  18  between a first position to a second position and vice-versa with little or no obstruction. 
         [0035]    With reference to  FIG. 5  in addition to  FIGS. 3 and 4 , the sheath  76  comprises an outer shroud  86  and a plurality of inner ribbing materials  88 , which are positioned adjacent the piston flange  50  and are connected to the flange and to the core  74 . In one exemplary embodiment, four equally spaced apart inner ribbing materials  88  are incorporated with each connected to both the core  74  and the piston flange  50  and having a gap or a flow path therebetween. The sheath  76  and the ribbing materials  88 , both made from a resilient material, provide the necessary returning forces to return the core  74  to its closed position from an open position, as further discussed below. However, the sheath alone  76  may provide the necessary resilient biasing force without the ribbing materials  88  by varying the resiliency or thickness of the sheath. 
         [0036]    A trough  90  is incorporated on the surface of the head section  78 . The trough resembles a trench or an indentation and is configured as a flow path for fluid flow flowing from a syringe or a medical implement (not shown) through the valve housing  12 , or vice versa. In an alternative embodiment, a plurality of protrusions are incorporated instead of or in addition to the trough  90  to provide the necessary flow paths on the top surface of the head section  78 . 
         [0037]    In one exemplary embodiment, two or more gills  87  are incorporated on the sheath  76 , with four equally spaced apart gills being more preferred. The gills  87  are formed by making small generally horizontal incisions on the sheath  87 , horizontal as compared to the axis defined by the core  74 . In one exemplary embodiment, the gills are cut after a the piston has been molded. In another exemplary embodiment, the cut gills undergo a post mold mechanical setting to set the slit. The gills  87  are in a closed position when the piston  18 , and hence the valve  10 , is in a first or closed position. In the closed position, no fluid will flow from a location in between the core  74  and the sheath  76  to a position external to the sheath  76 , and vice-versa. 
         [0038]      FIG. 6  is a semi-schematic perspective view of the valve  10  provided in accordance with aspects of the present invention in a second or used position. In the used position, the piston  18  is urged inwardly into the valve housing  12  by a medical implement (not shown), such as a syringe, to open fluid communication between the inlet opening  20  and the outlet opening  45 . A chamfer interior edge  92  is incorporated for facilitating insertion of the medical implement in the event of a misalignment between the tip of the medical implement and the opening  20 . 
         [0039]      FIG. 7  is a top view of the valve  10  of  FIG. 6  in the used position. 
         [0040]      FIG. 8  is a cross-sectional side view of the valve of  FIG. 7  taken along line C-C. The piston  18  is shown urged inwardly into the interior cavity  94  of the valve housing  12  by a medical implement (not shown). The piston  18  is moved a sufficient amount by the medical implement so that the trough  90  coincide with a plurality of internal flow channels  96 . Fluid expelled from a medical implement is configured to flow over the trough  90 , then in between the plurality of flow channels  96  and then onwards through the outlet nozzle  44 . In one exemplary embodiment, the plurality of internal flow channels  96  are formed by incorporating indentations on the interior surface  98  of the inlet nozzle  22 . Preferably, three or more equally spaced apart indentations are incorporated on the interior surface  98  adjacent the shoulder or flange  26  with four indentations being more preferred. 
         [0041]    The distal movement of the piston  18  towards the outlet nozzle  44  by the medical implement stretches the sheath  86  and the inner ribbing materials  88 . With reference to  FIG. 10 , which depicts the piston  18  in a second or used position outside of the valve body  12 , the stretched sheath  86  causes the gills  87  to expand. Thus, when the plunger  18  is in the second position, fluid communication is opened between the inlet opening  20  and the outlet opening  45  through the gills  87 . Hence, it accordance with aspects of the present invention, there is provided a plurality of spaced apart seals  87  comprising resilient surface to resilient surface contact for sealing the valve  10  and terminating fluid communication between the inlet opening  20  and the outlet opening  45 . In the piston  18  first position ( FIGS. 3 &amp; 4 ), fluid communication between the inlet opening  20  and the outlet opening  45  is further prevented by the surface contact between the outer perimeter rim  80  on the piston core  74  compressing against the interior surface of the inlet nozzle  22 . 
         [0042]      FIG. 9  is a semi-schematic cross-sectional side view of the valve  10  of  FIG. 8  taken along line D-D. In the view shown, the tapered lower end  82  of the core  74  is spaced apart from the interior surface  72  by gaps  100 . The gaps  100  provide flow space for fluid flow from between the inlet opening  20  and the outlet opening  45 . 
         [0043]    The valve  10  or piston  18  is moved from the second used position to its first position by simply removing the force exerted on the piston. The material elasticity of the sheath  86  and of the internal ribbing materials  88  ( FIGS. 4 ,  8 , and  9 ) recoil as the force is removed to return to its less stretched state. Thus, the valve moves from the FIGS.  8 / 9  position to the FIGS.  3 / 4  position by simply removing the medical implement from the inlet  14 . In one exemplary embodiment, the valve is essentially a neutral valve in that no noticeable net fluid flow into or out of the valve may be noticeable upon moving the piston from the second used position to its first position. However, the valve may be made a positive flush valve (i.e., a small amount of fluid is expelled out of the outlet upon moving the piston from the second position towards the first position) by ensuring a decrease in fluid volume space inside the valve when the piston moves from the second position towards the first position. 
         [0044]    Although limited embodiments of the needleless access valve assemblies and their components have been specifically described and illustrated herein, many modifications and variations will be apparent to those skilled in the art. For example, the inlet may incorporate a luer lock, the outlet may simply be a luer slip, the housing material could be opaque or semi-opaque, the various dimensions can vary, exterior angles and curvatures incorporated for aesthetic appeal, etc. Accordingly, it is to be understood that the valve assemblies and their components constructed according to principles of this invention may be embodied other than as specifically described herein. The invention is also defined in the following claims.
Needleless access port valves are generally discussed herein with particular discussions extended to needleless access port valves comprising a piston comprising an integrated gilled sheath. In accordance with aspects of the present invention, the sheath is secured to a valve housing and provides the needed recoil function to return a core from a second position to a first position to close the valve upon removal of a medical implement.