Protective caps for use with medical fluid fittings, and related methods

A protective cap for use with a medical fluid fitting including a fitting thread and a sealing portion having a sealing surface. The protective cap includes a body having a proximal end, a distal end, and a cap thread extending axially. The cap thread is configured to threadedly engage the fitting thread for releasably coupling the protective cap with the medical fluid fitting, and defines a tapered engagement surface. The tapered engagement surface tapers axially relative to a longitudinal axis of the body, and is configured to frictionally contact the fitting thread for retaining the protective cap in coupling engagement with the medical fluid fitting. The protective cap is configured to peripherally surround the sealing portion such that no portion of the protective cap contacts the sealing surface when the protective cap is coupled with the medical fluid fitting.

TECHNICAL FIELD

The present invention relates generally to medical fluid fittings, and more particularly, to caps for protecting sealing surfaces on medical fluid fittings.

BACKGROUND

Various types of fittings, or connectors, are often used for interconnecting conduit and other components in medical applications for conveying fluids. Such medical fluid fittings include a sealing portion having a sealing surface for forming a fluid-tight seal when mated with a corresponding sealing surface of a mating component, thereby ensuring reliable transfer of fluids. Such fittings and their corresponding sealing portions may be male or female. For example,FIG. 1Ashows a cross-sectional view of a known male medical fluid fitting1, including a male sealing portion2having a tapered sealing surface3for insertion into a mating component for forming a releasable seal with an inner surface thereof.FIG. 1Bshows a cross-sectional view of a known female medical fluid fitting4, including a female sealing portion5having a socket6and a tapered sealing surface7for receiving a mating component and forming a releasable seal with an outer surface thereof.

When the sealing surface of a medical fluid fitting is not in use, the sealing portion is preferably fitted with a protective cap to maintain the sealing surface free from debris and damage from warping, scratching, galling, and other malformations caused by surface contact. In this manner, the sealing surface may be preserved for optimal sealing performance. Preferably, the protective cap remains securely attached to the fitting such that the cap does not inadvertently detach from the fitting due to vibrations or impacts, such as those experienced during shipping and handling. Traditional caps rely on direct engagement with the sealing surface for maintaining a secure attachment to the fitting and retaining the cap in its protective position. However, such direct engagement may compromise the integrity of the sealing surface and thereby hinder the ability of the sealing surface to form an effective seal with a mating component during use.

Accordingly, there is a need for improved protective caps for use with medical fluid fittings that address the present challenges such as those discussed above.

SUMMARY

An exemplary embodiment of protective cap is provided for use with a medical fluid fitting that is configured to convey a fluid therethrough. The medical fluid fitting includes a fitting thread and a sealing portion having a sealing surface for forming a fluid tight seal with a mating part. The protective cap includes a body having a proximal end and a distal end, and a cap thread provided on the body and extending axially. The cap thread is configured to threadedly engage the fitting thread for releasably coupling the protective cap with the medical fluid fitting. The protective cap further includes a tapered engagement surface defined by the cap thread and tapering axially relative to a longitudinal axis of the body. The tapered engagement surface is configured to frictionally contact the fitting thread for retaining the protective cap in coupling engagement with the medical fluid fitting. The protective cap is configured to peripherally surround the sealing portion such that no portion of the protective cap contacts the sealing surface when the protective cap is coupled with the medical fluid fitting.

An exemplary medical fluid fitting assembly includes a medical fluid fitting configured to convey a fluid therethrough. The medical fluid fitting includes a fitting thread and a sealing portion having a sealing surface for forming a fluid tight seal with a mating part. The medical fluid fitting assembly further includes a protective cap configured to protect the sealing surface of the medical fluid fitting. The protective cap includes a body having a proximal end and a distal end, and a cap thread provided on the body and extending axially. The cap thread is configured to threadedly engage the fitting thread for releasably coupling the protective cap with the medical fluid fitting. The protective cap further includes a tapered engagement surface defined by the cap thread and tapering axially relative to a longitudinal axis of the body. The tapered engagement surface is configured to frictionally contact the fitting thread for retaining the protective cap in coupling engagement with the medical fluid fitting. The protective cap peripherally surrounds the sealing portion without contacting the sealing surface when the protective cap is coupled with the medical fluid fitting.

In use, an exemplary method is provided for protecting a sealing surface of a sealing portion of a medical fluid fitting, using a protective cap. The sealing surface is configured to form a fluid tight seal with a mating part so that fluid may pass through the medical fluid fitting. The method includes positioning a cap thread provided on a body of the protective cap in coaxial alignment with a fitting thread provided on the medical fluid fitting. The cap thread is threadedly engaged with the fitting thread to releasably couple the protective cap with the medical fluid fitting. The cap thread frictionally contacts the fitting thread to retain the protective cap in coupling engagement with the medical fluid fitting. The sealing portion of the medical fluid fitting is peripherally surrounded by the protective cap such that no portion of the protective cap contacts the sealing surface.

Various additional features and advantages of the invention will become more apparent to those of ordinary skill in the art upon review of the following detailed description of the illustrative embodiments taken in conjunction with the accompanying drawings.

DETAILED DESCRIPTION

Referring toFIGS. 2-7, a first exemplary embodiment of a male protective cap10in accordance with the principles of the invention is shown. The male protective cap10is adapted for use with a male medical fluid fitting12configured to convey fluids therethrough. As shown inFIG. 2, the male fluid fitting includes a collar14and a stem16extending axially from the collar14. The stem16is configured to be coupled to a medical conduit (not shown), such as a tubing, for forming a fluid-tight seal with the medical conduit so that fluid may pass through the conduit and into the fluid fitting12. The stem16may include a tapered portion18for facilitating insertion of the stem into the medical conduit. The stem16may additionally include any suitable retention features, such as a barb (not shown), for retaining the stem16in coupling engagement with a medical conduit.

Referring toFIGS. 3-5, additional features of the male protective cap10and the male fluid fitting12are shown. The male fluid fitting12includes a male sealing portion20, shown in the form of a tapered, nozzle-like protrusion, extending along a longitudinal axis of the male fluid fitting12. The male sealing portion20defines a sealing surface22, shown in the form of a tapered sealing surface, that is configured to form a fluid-tight seal with a mating female component (not shown). The sealing surface22may include a luer taper or any other suitable taper, for example. In this regard, although the male fluid fitting12is shown as having a tapered sealing surface22, persons skilled in the art will appreciate that various embodiments of male protective caps in accordance with the principles of the invention may be adapted as appropriate for male fluid fittings having various types of sealing surfaces other than tapered sealing surfaces.

The collar14of the male fluid fitting12circumferentially surrounds the male sealing portion20and includes a radially inner surface24that supports a helical fitting thread26which extends axially toward a base surface28of the sealing portion20(seeFIG. 7). The fitting thread26is configured to threadedly engage a corresponding thread of a mating component (not shown). Additionally, the fitting thread26may be an overhauling thread that is configured to de-thread and separate from the corresponding thread of a mating component when opposing axial forces are applied to the fluid fitting12and the mating component. A radially outer surface30of the collar14may include one or more gripping features, shown in the form of longitudinal grooves32, for aiding a user in gripping the fluid fitting during use, for example.

The male protective cap10, according to the embodiment shown, includes a base34and a tab36extending outwardly from the base34for facilitating manipulation of the protective cap10relative to the male fluid fitting12. A radially outer surface38of the base34may include one or more gripping features, shown in the form of notches40, which may generally correspond in width and depth to the grooves32on the fluid fitting12, and may aid a user in gripping the protective cap10during use.

As shown inFIGS. 3-5, a body42of the male protective cap10extends axially from the base34and includes a proximal end44and a distal end46. The proximal end44includes a shoulder48, which may include one or more cap vents50that extend radially through the shoulder48into a bore52, shown inFIG. 6, and cooperate with one or more fitting vents54formed on the fluid fitting12, as described in greater below. The cap body42includes a helical cap thread56that extends axially toward the distal end46. The cap thread56is configured to be threadedly engaged with the fitting thread26for releasably coupling the protective cap10with the fluid fitting12. As shown, the cap thread56may be formed with a width that tapers circumferentially at a thread start58and at a thread end60. Additionally, the cap thread56may be formed with one or more cut-out features62, which may be included for facilitating removal of the cap10from a mold during an injection-molding process during manufacture, for example.

As described below, protective caps of various embodiments in accordance with the principles of the invention include a tapered engagement surface defined by one of a root or a crest of the cap thread. The tapered engagement surface extends helically and tapers axially relative to a longitudinal axis of the cap body and is configured to frictionally engage a corresponding fitting thread on a medical fluid fitting for retaining the protective cap in coupling engagement with the medical fluid fitting. In the embodiment shown inFIGS. 2-7, the cap thread56of the male protective cap10includes a thread root64, a thread crest66, and a tapered engagement surface68defined by the thread root64.

As best shown inFIG. 6, the body42of the male protective cap10includes a cylindrical wall70defining the bore52that extends axially from the distal end46to the proximal end44and into the base34. As described above, the tapered engagement surface68is defined by the root64of the cap thread56and extends helically and tapers axially relative to the longitudinal axis of the cap body42. The tapered surface68tapers from a large diameter at the proximal end44of the cap body42to a smaller diameter at the distal end46of the cap body42. In this regard, the tapered surface68may extend proximally beyond the thread end60, up to the shoulder48. In this embodiment, an outer diameter defined by the crest66of the cap thread56remains substantially constant along an axial length of the cap thread56. Accordingly, a thread height of the cap thread56, defined by a radial distance between the thread root64and the thread crest66, decreases proximally. Additionally, the tapered surface68may include a circumferential lead-in feature74at the distal end46for facilitating initial threaded engagement of the cap thread56with the fitting thread26, as shown inFIG. 7.

The tapered engagement surface68tapers distally relative to the longitudinal axis of the cap body42. In one embodiment, the tapered surface68tapers with an included taper angle of approximately three degrees to approximately six degrees, and thus with a non-included taper angle θ of approximately 1.5 degrees to approximately three degrees, as shown inFIG. 6. Other embodiments of protective caps in accordance with the principles of the invention, including those shown and described herein, may also include tapered engagement surfaces that taper relative to a longitudinal axis of the corresponding cap body with an included taper angle of approximately three degrees to approximately six degrees, and a non-included taper angle θ of approximately 1.5 degrees to approximately three degrees.

As shown inFIG. 7, the male protective cap10may be releasably coupled with the male fluid fitting12such that the cap body42peripherally surrounds the male sealing portion20without contacting the sealing surface22. In this manner, the protective cap10may shield the sealing surface22from unwanted contact with ambient elements and conditions. More specifically, the externally-threaded cap body42is coaxially aligned with the internally-threaded fitting collar14and inserted therein such that the male sealing portion20is received within the bore52of the cap body42. The protective cap10is rotated about its longitudinal axis, for example using the tab36, so that cap thread56threadedly engages the fitting thread26. As shown, the shoulder48of the cap body42may contact the radially inner surface24of the collar14to promote axial alignment of the protective cap10with the fluid fitting12.

As the male protective cap10is rotated into increased threaded engagement with the male fluid fitting12, a trailing side76of the cap thread56engages the fitting thread26to advance the distal end46of the cap body42axially toward the base surface28of the male sealing portion20. Simultaneously, the tapered engagement surface68defined by the root64of the cap thread56exerts a radial, outwardly-directed compressive force on, and thereby frictionally contacts, a thread crest78of the fitting thread26. In one embodiment, as shown, no portion of the cap thread56contacts a thread root80of the fitting thread26, such that a radial gap is formed between the crest66of the cap thread56and the root80of the fitting thread26. The radial compressive force exerted on the fitting thread26by the tapered surface68, for example by a proximal portion82thereof, increases progressively as threaded engagement of the cap thread56and the fitting thread increases26.

In this manner, an interference fit is created between the cap thread56and the fitting thread26, thereby retaining the protective cap10in coupling engagement with the fluid fitting12. Accordingly, although the fitting thread26may be an overhauling-type thread, as described above, the threaded engagement between the fitting thread26and the cap thread56may be a non-overhauling-type engagement. Thus, the male protective cap10and the female fluid fitting12do not de-thread and separate from each other upon application of opposing axial forces on the protective cap10and the fluid fitting12.

As shown inFIG. 7, the male fluid fitting12includes a first bore84extending through the male sealing portion20, and a second bore86extending through the stem16, the first and second bores84,86being connected in fluidic communication to define a fluid flow path for conveying fluids. In one embodiment, the cap vents50provided on the cap body42may extend and taper radially through the shoulder48and be arranged in fluidic communication with the cap bore52. Accordingly, when the protective cap10is coupled with the fluid fitting12, as shown inFIG. 7, the cap vents50are positioned in fluidic communication with the fluid flow path on one side and with an ambient environment on another side, via the fitting vents54(seeFIGS. 3-5). In this manner, gasses residing within the fluid flow path may be released through the cap vents50and the fitting vents54to an ambient environment.

Referring toFIGS. 8-11, a first exemplary embodiment of a female protective cap90in accordance with the principles of the invention is shown. The female protective cap90is adapted for use with a female medical fluid fitting92configured to convey fluids therethrough. As shown inFIGS. 8 and 9, the female fluid fitting92includes a base94and a stem96extending axially from the base94. A radially outer surface97of the base94may include one or more gripping features, shown in the form of notches98, for aiding a user in gripping the fluid fitting92during use. The stem96is configured to be coupled to a medical conduit (not shown), such as a tubing, for forming a fluid-tight seal with the medical conduit so that fluid may pass through the conduit and into the fluid fitting. The stem96may include a barb100for retaining the stem96in coupling engagement with the medical conduit and forming a fluid-tight seal with the conduit.

As best shown inFIGS. 9 and 11, the female fluid fitting92includes a female sealing portion102extending axially from the base94. The female sealing portion102includes a circumferential wall104and a fitting socket106extending along a longitudinal axis of the fluid fitting92and defining a sealing surface108, shown in the form of a tapered sealing surface. The sealing surface108is configured to form a fluid-tight seal with a mating male component (not shown), and may include a luer taper or any other suitable taper, for example. As described above in connection with the male fluid fitting12ofFIGS. 2-7, various embodiments of female protective caps in accordance with the principles of the invention may be adapted as appropriate for female fluid fittings having various types of sealing surfaces other than tapered sealing surfaces.

A radially outer portion of the circumferential wall104of the female sealing portion102includes a helical fitting thread110extending axially. The fitting thread110is configured to threadedly engage a corresponding thread of a mating component (not shown). Additionally, the fitting thread110may be an overhauling-type thread that it is configured to de-thread and separate from the corresponding thread of a mating component when opposing axial forces are applied to the mating component and the fluid fitting92.

As shown inFIGS. 9 and 10, the female protective cap90includes a body112having a proximal end114and a distal end116. The body112includes a circumferential wall118that is integrally formed with an end wall120at the proximal end114and defines a cap socket122extending along a longitudinal axis of the body112. A radially inner surface124of the circumferential wall118supports a helical cap thread126that extends axially from the distal end116toward the proximal end114. As shown, the cap thread126may extend up to the end wall120, for example. The cap thread126is configured to be threadedly engaged with the fitting thread110for releasably coupling the female protective cap90with the female fluid fitting92, as described in greater detail below. In that regard, a radially outer surface128of the cap body112may include one or more gripping features, shown in the form of longitudinal grooves130, for aiding a user in gripping the protective cap90when coupling the cap90with the fluid fitting92, described in greater detail below.

In the embodiment shown, the cap thread126of the female protective cap90includes a thread root132, a thread crest134, and a tapered engagement surface136defined by the thread root132. The tapered engagement surface136extends helically and tapers proximally relative to the longitudinal axis of the body112. As shown, the tapered surface136tapers from a large diameter at the distal end116of the cap body112to a smaller diameter at the proximal end114of the cap body112. In one embodiment, an inner diameter defined by the crest134of the cap thread126remains substantially constant along an axial length of the cap thread126. Accordingly, a thread height of the cap thread126, defined by a radial distance between the thread root132and the thread crest134, decreases proximally.

Similar to the tapered engagement surface68of the male protective cap10ofFIGS. 2-7, the tapered engagement surface136of the female protective cap90may taper with an included taper angle of approximately three degrees to approximately six degrees relative to the longitudinal axis of the cap body112. Accordingly, as shown inFIG. 10, the tapered surface136may taper with a non-included taper angle θ of approximately 1.5 degrees to approximately three degrees relative to the cap body112.

As shown inFIG. 11, the female protective cap90may be releasably coupled with the female fluid fitting92such that the cap body112peripherally surrounds the female sealing portion102without contacting the sealing surface108. More specifically, the internally-threaded cap body112is coaxially aligned with the externally-threaded female sealing portion102, which is received within the cap socket122. The protective cap90is then rotated about its longitudinal axis, for example with the aid of grooves130, to threadedly engage the cap thread126with the fitting thread110.

As the female protective cap90is rotated into increased threaded engagement with the female fluid fitting92, a trailing side137of the cap thread126engages the fitting thread110to advance the distal end116of the cap body112axially toward the base94of the female fluid fitting92. Simultaneously, as similarly described above, the tapered engagement surface136defined by the root132of the cap thread126exerts a radial, inwardly-directed compressive force on, and thereby frictionally contacts, a crest138of the fitting thread110. In one embodiment, as shown, no portion of the cap thread126contacts a thread root140of the fitting thread110, such that a radial gap is formed between the crest134of the cap thread and the root140of the fitting thread110. The radial compressive force exerted on the fitting thread110by the tapered surface136, for example by a proximal portion142thereof, increases progressively as threaded engagement of the cap thread126and the fitting thread110increases.

In this manner, an interference fit is created between the cap thread126and the fitting thread110, thereby retaining the female protective cap90in coupling engagement with the female fluid fitting92. Accordingly, although the fitting thread110may be an overhauling-type thread, as described above, the threaded engagement between the fitting thread110and the cap thread126may be a non-overhauling-type engagement. Thus, the female protective cap90and the female fluid fitting92do not de-thread and separate from each other upon application of opposing axial forces on the protective cap90and the fluid fitting92.

In summary, described above in connection withFIGS. 2-11are first exemplary embodiments of male and female protective caps10,90, each including a tapered engagement surface68,136defined by a root64,132of the corresponding cap thread56,126. Now described below, in connection withFIGS. 12-17, are second exemplary embodiments of male and female protective caps10a,90a, each including a tapered engagement surface68a,136adefined by a crest66a,134aof the corresponding cap thread56a,126a.

Referring toFIGS. 12-14, a second exemplary embodiment of a male protective cap10ain accordance with the principles of the invention is shown, for which similar reference numerals refer to similar features shown inFIGS. 2-7. The male protective cap10amay be adapted for use with the male medical fluid fitting12, for example. As described above, persons skilled in the art will appreciate that the male protective cap10amay be modified as appropriate for use with male medical fluid fittings having various types of sealing surfaces, including tapered sealing surfaces.

As shown inFIGS. 12 and 13, a body42aof the male protective cap10aincludes a helical cap thread56ahaving a thread root64a, a thread crest66a, and a tapered engagement surface68adefined by the thread crest66a. An outer diameter defined by the crest66aof the cap thread56aincreases proximally while a diameter defined by the root64aof the cap thread56aremains substantially constant along the axial length of the cap thread56a. Accordingly, a thread height of the cap thread56a, defined by a radial distance between the thread root64aand the thread crest66a, increases proximally.

Similar to the male cap10shown inFIGS. 2-7, the tapered engagement surface68aof male cap10atapers distally relative to the longitudinal axis of the cap body42a. In one embodiment, the tapered surface68atapers with an included taper angle of approximately three degrees to approximately six degrees, and with a non-included taper angle θ of approximately 1.5 degrees to approximately three degrees, as shown inFIG. 13.

As shown inFIG. 14, the male protective cap10amay be releasably coupled to the male fluid fitting12such that the cap body42aperipherally surrounds the male sealing portion20without contacting the sealing surface22. In that regard, the male cap10amay be coaxially aligned and coupled with the male fluid fitting12in a manner similar to that described above in connection with the male cap10shown inFIG. 7, such that the cap thread56athreadedly engages the fitting thread26.

In the embodiment shown inFIG. 14, as the male protective cap10ais rotated into increased threaded engagement with the male fluid fitting12, the tapered surface68adefined by the crest66aof the cap thread56aexerts a radial, outwardly-directed compressive force on, and thereby frictionally contacts, the root80of the fitting thread26. In one embodiment, as shown, no portion of the cap thread56acontacts the crest78of the fitting thread26, such that a radial gap is formed between the root64aof the cap thread56aand the crest78of the fitting thread26. The radial compressive force exerted on the fitting thread26by the tapered surface68a, for example by a proximal portion82athereof, increases progressively as threaded engagement of the cap thread56aand the fitting thread26increases. In this manner, an interference fit is created between the cap thread56aand the fitting thread26, thereby retaining the protective cap10ain coupling engagement with the fluid fitting12.

Referring toFIGS. 15-17, a second exemplary embodiment of a female protective cap90ain accordance with the principles of the invention is shown, for which similar reference numerals refer to similar features shown inFIGS. 8-11. The female protective cap90amay be adapted for use with the female medical fluid fitting92, for example. As described above, persons skilled in the art will appreciate that the female protective cap90amay be modified as appropriate for use with female medical fluid fittings having various types of sealing surfaces, including tapered sealing surfaces.

As shown inFIGS. 15 and 16, a body112aof the female protective cap90aincludes a circumferential wall118ahaving a radially inner surface124athat supports a helical cap thread126a. The cap thread126aincludes a thread root132a, a thread crest134a, and a tapered engagement surface136adefined by the thread crest134a. The tapered surface136atapers from a large diameter at the distal end116aof the cap body112ato a smaller diameter at the proximal end114aof the cap body112a. In one embodiment, an inner diameter defined by the thread root132aremains substantially constant along an axial length of the cap thread126a. Accordingly, a thread height of the cap thread126a, defined by a radial distance between the thread root132aand the thread crest134a, increases proximally.

Similar to the tapered engagement surface136of the female protective cap90shown inFIGS. 8-11, the tapered engagement surface136aof female protective cap90atapers proximally relative to the longitudinal axis of the cap body112a. In one embodiment, the tapered surface136tapers with an included taper angle of approximately three degrees to approximately six degrees, and with a non-included taper angle θ of approximately 1.5 degrees to approximately three degrees, as shown inFIG. 16.

As shown inFIG. 17, the female protective cap90amay be releasably coupled to the female fluid fitting92such that the cap body112aperipherally surrounds the female sealing portion102without contacting the sealing surface108. In that regard, the female cap90amay be coaxially aligned and coupled with the female fluid fitting92in a manner similar to that described above in connection with the female cap90shown inFIG. 11, such that the cap thread126athreadedly engages the fitting thread110.

In the embodiment shown inFIG. 17, as the female protective cap90ais rotated into increased threaded engagement with the female fluid fitting92, the tapered surface136adefined by the crest134aof the cap thread126aexerts a radial, inwardly-directed compressive force on, and thereby frictionally contacts, the root140of the fitting thread110. In one embodiment, as shown, no portion of the cap thread contacts the crest138of the fitting thread, such that a radial gap is formed between the root132aof the cap thread126aand the crest138of the fitting thread110. The radial compressive force exerted on the fitting thread110by the tapered surface136a, for example by a proximal portion142athereof, increases progressively as threaded engagement of the cap thread126aand the fitting thread110increases. In this manner, an interference fit is created between the cap thread126aand the fitting thread110, thereby retaining the female protective cap90ain coupling engagement with the female fluid fitting92.

While the present invention has been illustrated by the description of specific embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. The various features discussed herein may be used alone or in any combination. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the general inventive concept.