Abstract:
A removal tool for a needle shield includes an attachment cavity having an interior wall extending along a length of the attachment cavity and accessible via a sidewall aperture. The interior wall is sized to receive and engage the needle shield. A pull ring is connected to and extends from a proximal end of the attachment cavity. The pull ring has an exterior wall extending along an outer circumference of the pull ring and an interior wall extending along an inner circumference of the pull ring. The inner circumference is sized to accommodate at least one finger of a user.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a Section 371 of International Application No. PCT/US2013/055535, filed Aug. 19, 2013, which was published in the English language on Feb. 27, 2014, under International Publication No. WO 2014/031521 A1, and the disclosure of which is hereby incorporated by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to syringes and, more particularly, to a tool for removing syringe needle shields. 
     Syringes are known in the art as medical devices utilizable for delivering medicament to a patient. Syringes typically include a barrel component and a plunger component. During injection, the plunger forces the medicament out of a distal end of the barrel, through an elongated needle having an interior bore, out of a tip located at the distal end of the needle and into a patient. The needle tip has a geometry that allows the needle to easily puncture a patient&#39;s skin and penetrate tissue or a vein. In order to prevent a needle stick, or damage or contamination of the needle tip, syringe assemblies typically include a syringe needle shield, which is essentially a cover that is placed over the needle to enclose the needle tip. The shield also prevents a needle stick before and after using the syringe. 
     However, the act of removing a needle shield from a syringe assembly is a significant contributor to accidental needle stick injuries. Using both hands, a user typically pulls apart the needle shield from the syringe assembly. When the needle shield is released from the syringe assembly, the user&#39;s body reflexes to compensate for the sudden movement caused by the removal. Both of the user&#39;s hands often recoil, directing the exposed needle tip back toward the user&#39;s hand that is holding the removed needle shield, sometimes causing the exposed needle tip to inadvertently stick the user. In addition to being painful, the inadvertent needle stick can transmit diseases, such as HIV or Hepatitis, if the needle is contaminated. Previous developments have attempted to address this problem. 
     U.S. Pat. No. 4,915,225 to Tabor, Jr. et al, describes a counter-top mounted needle shield removal device which has two elongated U-shaped cavities, each of which may receive a needle shield that is capped onto a distal end of a syringe barrel. After the needle shield is inserted into a cavity of the removal device at an acute angle, a compression spring within the removal device pushes a distal end of the needle shield toward a proximal end of the cavity. As the needle shield is pushed by the spring, a proximal end of the needle shield engages a mechanical stop located at the proximal end of the cavity. The spring pressure and the mechanical stop effectively lock the needle shield within the cavity so a user can then pull the syringe barrel away from the needle shield with one hand. 
     If a needle shield is too long, the cavity can not receive and hold the needle shield. If a needle shield is too short, there is insufficient spring pressure to properly secure the needle shield within the cavity. Requiring a compression spring increases manufacturing difficulty and cost. The device must also be mounted to a wall or counter top, which limits the convenience and operability to a user. 
     U.S. Pat. No. 5,183,469 to Capaccio discloses a mounted needle shield removal tool having a single cylindrical cavity that receives a needle shield. A needle shield is inserted into a proximal end of the cavity and is twisted to engage internal screw threads at a distal end of the cavity, creating a mechanical lock that anchors the needle shield within the removal device. Once the needle shield is anchored, the user can pull the syringe barrel away from the removal device. If the screw threads within the removal tool cannot engage or do not fully engage the needle shield, the device is rendered inoperable. Hand operation alone is unsuitable because the device must be mounted to a surface, limiting convenience to the user. 
     U.S. Pat. No. 5,512,049 to Fallas discloses a mounted needle shield removal tool comprising two parallel plates, each having U-shaped arms that extend outwardly in the same direction. A space is provided between the parallel plates for receiving a flange on a needle shield. The top U-shaped plate has an extension, which is secured to a table top. After inserting the flange of the needle shield into the space between the parallel plates, the user pulls on the syringe barrel with one hand. The proximal end of the flange engages a distal end of the top U-shaped plate, preventing the needle shield from moving with the syringe barrel, which separates the syringe barrel from the needle shield. This device can only be used with needle shields that include a suitably sized flange. Hand operation alone is unsuitable because the device must be mounted to a surface, limiting convenience to the user. 
     U.S. Pat. No. 5,087,249 to Deal discloses a hand operated needle shield removal and attachment device comprising clips that define a C-shaped cavity. The clips surround a portion of a outer wall of a needle shield. A handle on the attachment device extends from the C-shaped cavity toward a proximal end of a syringe barrel. The handle allows the user to attach the needle shield to the device without having to directly grasp the needle shield. However, in order to remove the needle shield, the user must directly pinch the clips, which may expose a user to an inadvertent needle stick during recoil. While the device of Deal can be operated solely by hand, the user is provided with little protection when removing the needle shield from the syringe assembly. 
     WO 03/051423 discloses a hand operated, needle shield removal tool comprising a cylindrical cavity, a top guard plate, and a bottom base plate. The top guard plate is parallel to the bottom base plate, and both plates are perpendicular to, and centered on, the cylindrical cavity. A syringe with a needle shield is inserted into a proximal end of the cylindrical cavity, and the needle shield is gripped by a plurality of spring-like fingers so that when the syringe is pulled upwardly the needle shield is removed. The arrangement of the guard plate and the cylindrical cavity puts the user&#39;s hand immediately adjacent to the proximal end of the cylindrical cavity. With the guard plate having such a small surface area, any reflex during detachment potentially causes the uncovered portion of the user&#39;s fingers to be inadvertently stuck by the needle. 
     Accordingly, there is a continuing need for an improved hand operated needle shield removal tool that overcomes, alleviates, or mitigates one or more of the aforementioned drawbacks and deficiencies of the prior art. The present invention addresses the aforementioned problems by providing a pull ring integrally formed to an attachment cavity that engages and holds a needle shield. The pull ring facilitates the removal of a needle shield for users having reduced manual dexterity while also reducing recoil to minimize the potential for needle sticks. 
     BRIEF SUMMARY OF THE INVENTION 
     Briefly stated, a preferred embodiment of the present invention comprises a removal tool for a needle shield. The tool includes an attachment cavity having an interior wall extending along a length of the attachment cavity and accessible via a sidewall aperture. The interior wall is sized to receive and engage the needle shield. A pull ring is connected to and extends from a proximal end of the attachment cavity. The pull ring has an exterior wall extending along an outer circumference of the pull ring and an interior wall extending along an inner circumference of the pull ring. The inner circumference is sized to accommodate at least one finger of a user. 
     Another embodiment of the present invention comprises a needle shield assembly including a needle shield having an outer diameter, a distal end configured to cover a needle, and a proximal end opposite the distal end. A removal tool includes an attachment cavity having an interior wall extending along a length of the attachment cavity and accessible via a sidewall aperture. The interior wall complementarily receives and engages the needle shield. A pull ring is connected to and extends from a proximal end of the attachment cavity. The pull ring has an exterior wall extending along an outer circumference of the pull ring and an interior wall extending along an inner circumference of the pull ring. The inner circumference is sized to accommodate at least one finger of a user. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The foregoing summary, as well as the following detailed description of a preferred embodiment of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings an embodiment which is presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. 
       In the drawings: 
         FIG. 1  is a top front perspective view of a needle shield removal tool in accordance with a preferred embodiment of the present invention; 
         FIG. 2  is a top rear perspective view of the needle shield removal tool of  FIG. 1 , attached to a needle shield; 
         FIG. 3  is a top plan view of the needle shield removal tool of  FIG. 1 ; 
         FIG. 4  is a bottom plan view of the needle shield removal tool of  FIG. 1 ; 
         FIG. 5  is an enlarged rear elevational view of the needle shield removal tool of  FIG. 1 ; 
         FIG. 6  is an enlarged front elevational view of the needle shield removal tool of  FIG. 1 ; and 
         FIG. 7  is an enlarged side elevational view of the needle shield removal tool of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Certain terminology is used in the following description for convenience only and is not limiting. The words “right,” “left,” “lower” and “upper” designate directions in the drawings to which reference is made. The words “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of the piston and designated parts thereof. Unless specifically set forth herein, the terms “a”, “an” and “the” are not limited to one element but instead should be read as meaning “at least one”. The terminology includes the words noted above, derivatives thereof and words of similar import. 
     Referring to the drawings, there is shown a needle shield removal tool  10  in accordance with a preferred embodiment of the present invention. The needle shield removal tool  10  comprises two principal components, a pull ring  12  and an attachment cavity  14 , which may be engaged with a needle shield  48  of a syringe, as shown in  FIG. 2 . The present invention is usable for removal of a generally cylindrical elongated needle shield  48  from a syringe (not shown). Such needle shields  48  are held onto the distal end of a syringe by an interference or frictional fit. It should be clearly understood that the present invention is not limited to the below described embodiment. 
     Referring to  FIGS. 3 and 4 , the pull ring  12  in the present embodiment is generally oblong or ellipsoidal and has a minor axis length  30  and a major axis length  32 . The length of the major axis  32  provides a safeguard distance that separates a user&#39;s fingers from a needle tip of a syringe (not shown), which is exposed during removal of the needle shield  48 . It will be appreciated by those skilled in the art that the minor axis  30  and major  32  axis can alternate positions, and the lengths of the minor axis  30  and major axis  32  can be equal, creating a circle. The pull ring  12  may also be triangular, square, rectangular, trapezoidal, or some other shape. The pull ring  12  in the present embodiment has a radial thickness  50  and a height or axial thickness  36 , both of which may vary along the circumference of the pull ring  12  if desired. It will be appreciated by those skilled in the art that the thickness  50 , height  36 , major axis length  32 , and minor axis length  30  may all vary in size, but preferably are selected such that the user may comfortably and securely extend one or more fingers through the pull ring  12  to grip the pull ring  12  when removing a needle shield  48  from a syringe barrel as described below. 
     Referring to  FIGS. 1 and 2 , the pull ring  12  has an interior wall  42  suitable for finger placement during use, which runs along the inner-circumference of the pull ring  12 . The interior wall  42  may have a surface that is smooth, dimpled, cross-hatched, or some other topography. The interior wall  42  meets an interior top surface  52  to form a corner, which may be square, rounded, or some other shape. The pull ring  12  further comprises an exterior wall  38 , which also meets an exterior top surface  54  to form a corner that may be square, rounded, or some other shape. The exterior wall  38  runs along the outer-circumference of the pull ring  12 , and may also have a surface that is smooth, dimpled, cross-hatched, or some other topography. 
     A generally U-shaped, tapered cavity  40  is positioned between the exterior top surface  54  and the interior top surface  42  of the pull ring  12 . A similar cavity  40  may also be provided on the bottom or both the top and bottom surfaces of the pull ring  12 , as shown in  FIG. 5 . The cavities  40  reduce the amount of material required to produce the needle shield removal tool  10  while also creating a valley between the exterior wall  38  and the interior wall  42 . The valley provides additional surface area for the user to grip while operating the needle shield removal tool  10  in accordance with the present invention. 
     An intermediate wall  56  may be positioned between the interior wall  42  and the exterior wall  38 . It will be appreciated by those skilled in the art that the placement of the intermediate wall  56  may vary along the circumference of the pull ring  12 . Placing one or more intermediate walls  56  in the cavity  40 , between the exterior wall  38  and the interior wall  42 , may split a single valley into two or more valleys. The intermediate wall  42  may be on the top surface, bottom surface, or both the top and bottom surfaces of the pull ring  12 . 
     Referring to  FIGS. 1, 2, and 3 , the attachment cavity  14  is suitable for receiving and engaging a needle shield  48 . The attachment cavity  14  comprises a sidewall aperture  44 , which, in plan view, is a generally rectangular shaped opening, and reveals an interior wall  16  of the attachment cavity  14 . The sidewall aperture  44  may also be trapezoidal, ellipsoidal, or some other shape, but preferably is suitably shaped to receive a needle shield  48 . The opening created by the sidewall aperture  44  spans the length  20  of the attachment cavity  14  and preferably at most about 50% of the circumference of the attachment cavity  14 . Aperture lips  46  span the length  20  of the sidewall aperture  44 . The aperture lips  46  may be square, rounded, or some other shape. A distance  58  between the aperture lips  46  is preferably about the same size or at least slightly smaller than the outer diameter of the needle shield  48 . The distance  58  between aperture lips is circumferentially large enough to receive the needle shield  48 , but the distance  58  is also circumferentially small enough to provide the frictional retention necessary to prevent the installed needle shield  48  from being inadvertently dislodged from the attachment cavity  14  during removal from the syringe barrel. 
     Referring to  FIGS. 1, 2, 3, and 5 , the length  20  of the attachment cavity  14  extends from a base wall  28 , which is proximate to the pull ring  12 , to a collar stop  18 . The length  20  of the attachment cavity  14  is at least slightly greater than the length of the needle shield  48 , but may vary in some applications. The base wall  28  and the collar stop  18  are both generally perpendicular to the inner cavity wall  16 , as shown in  FIGS. 2 and 3 . A collar aperture  26  located at the center of the collar stop  18 , and may be circular, square, rectangular, ellipsoidal, or some other shape, but preferably is shaped to receive a portion of a syringe barrel. The collar stop  18  has a width  24  that spans from the inner cavity wall  16  to the collar aperture  26 . as shown in  FIG. 5 . 
     Referring to  FIGS. 1, 2, 3, and 5  an inner diameter  22  of the attachment cavity  14 , which is measured at the inner cavity wall  16 , is preferably the same or at least slightly greater than the outer diameter of the needle shield  48 . The collar aperture  26  is at least slightly smaller than the outer diameter of a needle shield  48  so that a proximal end  34  of an installed needle shield  48  engages a distal end  19  of the collar stop  18 , as shown in  FIGS. 1 and 2 . The width  24  of the collar stop  18  is preferably small enough to provide a clearance between a distal end of the syringe barrel and the collar aperture  26 . 
     In use, the needle shield  48  is first centered on the aperture lips  46  of the attachment cavity  14  with the distal end of the needle shield  48  at or near the base wall  28  and the proximal end of the needle shield  48  at or near the distal end  19  of the collar stop  18 . Because the distance  58  between the aperture lips  46  is the same or slightly less than the exterior diameter of the needle shield  48 , the user must press the needle shield  48  so that the aperture lips  46  spread apart at least slightly. With sufficient pressure from the user&#39;s fingers, the needle shield  48  is installed into the attachment cavity  14  by passing through the aperture lips  46  and snapping into the attachment cavity  14 . When positioning the needle shield  48  against the aperture lips  46 , the proximal end of the needle shield  48  must be at or adjacent to the distal side  19  of the collar stop  18  with the syringe barrel in the collar aperture  26  (not shown). The attachment cavity  14  secures the needle shield  48  by engaging the distal end  19  of the collar stop  18  with the proximal end of the needle shield  48 . Once inserted, the user places one or more fingers of one hand inside of the pull ring  12  while holding the syringe barrel with the other hand and leverages the interior wall  42 , pulling the needle shield removal tool  10  in accordance with the present invention away from the syringe and separating the needle shield  48  from the syringe barrel. 
     The cavities  40  provide additional surface area on the pull ring  14 , enhancing the user&#39;s grip. Better control over the pull ring  12  combined with the safeguard distance provided by the major axis  32  of the pull ring  12 , which separates the user&#39;s fingers from the exposed needle tip, prevents inadvertent needle sticks of the hand holding the pull ring  12  during removal of the needle shield  48 . 
     The needle shield removal tool  10  in accordance with this invention can be manufactured by injection molding polymeric materials include polyethylene, polypropylene, polyurethane, polysiloxane, or other suitable materials. The proximal end of the pull ring  12  is preferably integrally formed with the exterior distal end of attachment cavity  14 . The arrangement of pull ring  12  and attachment cavity  14  allows polymeric materials to be injection molded as a single shot. Therefore all of the needle shield removal tool components are integrally formed as a single piece, providing cost-effective and robust manufacturing processes. If desired, the attachment cavity  14  and the pull ring  12  may be separately formed and thereafter secured together in any suitable manner. 
     From the foregoing, it can be seen that the present invention comprises a tool for attaching to syringes to facilitate the removal of a needle shield. It will be appreciated by those skilled in the art that changes could be made to the embodiment described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiment disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.