Abstract:
Disclosed are embodiments of a cap covering a needle on a syringe. The cap in the closed configuration is sized and dimensioned to cover the needle, and after the cap is removed from the needle the cap assumes an open configuration that is not readily usable to re-cap the needle.

Description:
[0001]    This application claims priority to U.S. provisional patent application having Ser. No. 61/969,462, filed Mar. 24, 2014, the contents of which are incorporated herein by reference in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention generally relates to a single-use shield or cap for a syringe needle and the like, which after the first and only use the shield or cap assumes a shape that discourages recapping of the exposed needle. 
       BACKGROUND OF THE INVENTION 
       [0003]    A significant number of needle stick injuries, i.e., about 30%, occurs during disposal of used syringes and needles. A large portion of those injuries happen when the users attempt to re-cap the needles after they have been used. Despite industry guidance against recapping used needles, many users still perceive a recapped needle to be safer than an exposed needle, and needle stick injuries remain high. Standard needle caps, or rigid needle shields, as they are known in the art, do not communicate to the user through their form or design that they should not be recapped. In fact, it could be argued that they communicate the opposite, as their form resembles that of pen caps or other items that users typically recap. 
         [0004]    There are some cap designs that prevent the cap from being securely replaced and would simply fall off if the user tries to recap it. This design, however, requires the user to learn that the cap cannot be replaced by first attempting to replace the cap and then seeing that it would not securely cap. These attempted recaps can result in needle stick injuries, and the users can still be injured with this design. 
         [0005]    There remains a need for cap designs that readily communicate to the user that the caps after being removed from the needle or syringe should not be used to recap the exposed needle. 
       SUMMARY OF THE INVENTION 
       [0006]    Hence, the invention is directed to needle caps that once removed from covering the needle communicate to the user preferably through the form, function and/or appearance of the caps that the caps are not meant to be replaced or repositioned to cover the needle. 
         [0007]    The invention is also directed to needle caps that once removed from the needle substantially change their shape permanently or self-destruct to communicate to the users that the caps do not go back onto the needle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    In the accompanying drawings, which form a part of the specification and are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views: 
           [0009]      FIG. 1  is a top view of a syringe with a conventional needle cap; 
           [0010]      FIG. 2( a )  is a top view of an embodiment of the inventive needle cap in the before use or first configuration;  FIG. 2( b )  is a top view of the inventive needle cap in the after use or second configuration; and  FIG. 2( c )  is an exploded cross-sectional view of a live hinge joint; 
           [0011]      FIGS. 3( a )-( c )  are other embodiments of the inventive cap; 
           [0012]      FIG. 4( a )  is a top view of another embodiment of the inventive needle cap in the before use or first configuration;  FIG. 4( b )  is an end view of the of the needle cap of  FIG. 4( a ) ; and  FIGS. 4( c ) and 4( d )  are end views of the inventive needle cap of  FIGS. 4( a ) and 4( b )  in the after use or second configuration; and 
           [0013]      FIG. 5  is a schematic illustration of the embodiment shown in  FIGS. 4( a )-4( d ) . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0014]    Needle shields/caps are used with syringes. Syringes consist of a hollow barrel fitted with a plunger and, may be cartridges, hypodermics, single use syringes, multiple use syringes, auto-injectors, and the like. In order to communicate to the user that needle shields/caps onced used and removed from the syringe should not be used to recap the exposed needles, the present invention provides a self-destructing needle cap or a needle cap that substantially permanently changes its shape or configuration after the first use. The inventive needle cap in one embodiment consists of two or more segments hinged at the top, but free to extend or expand like flower petals. When placed over the needle, the petals would close around the needle and be secured by a retaining structure. The petals may be secured by a variety of structures, including but not limited to, a slideable band over the petals and an overhanging feature from the syringe to retain the petals, or be attached by breakable connections to a stationary ring attached to the syringe, much like a bottle cap connected to a lower ring for tamper detection. The petals may also be secured by a shrink wrap plastic sleeve that has a scored or weakened element or that has an embedded string to tear the wrap, similar to the safety shrink wrap sleeves common to over-the-counter medicines. Once the user removes the cap from the needle, the petals or segments would then expand and open like a flower opening its petals. 
         [0015]    The petals could be sprung open by pressure from an elastomer core, which is a common needle shield for prefilled syringes that incorporates a rigid plastic shield with an elastomer core inside to seal the needle. The core is compressed when the petals are secured together, or from a geometric feature of the rigid cap itself molded into the plastic. Suitable geometric features include, but are not limited to, a shape memory alloy (SMA) that remembers its shape and connects the petals to the cap. In another embodiment, the petals form a live hinge with the remaining portion of the cap and when secured to the other petal(s) form a spring joint or a live hinge joint, discussed below. Thus the needle cap, in a sense, self-destructs and it is clear to the user that it would no longer function as a needle cap. The user would intuitively know that the cap could not and should not be replaced, and so would not attempt to replace it, thus eliminating the risk of needle stick injury. Another benefit of the self-destructing needle shield is that it can also serve as a tamper evident closure and anticounterfeiting protection. 
         [0016]    Referring to  FIG. 1 , syringe  10  with an inventive needle cap  12  is shown. Cap  12  covers a hypodermic needle that injects a medicine or vaccine or the like into a patient. A first embodiment of inventive needle cap  12  is shown in  FIGS. 2( a ) and 2( b ) . Cap  12  comprises tip  14  with petals  16 . While two petals  16  are illustrated in this embodiment, a single or two or more petals  16  can be employed and the present invention is not limited to any particular number of petals. Within cap  12 , preferably elastomeric core  18  is present and a needle  19  is pushed into and sealed by core  18  (see  FIG. 5 ). 
         [0017]    Cap  12  can be molded from a polymeric plastic, and as molded has the open configuration or shape shown in  FIG. 2( b ) , i.e., with the petals opened. Petals  16  are joined to tip  14  by at least one live hinge  20 . A live hinge is a flexible hinge made from the same material as the two pieces it connects. The live hinge is generally thinner than the two connecting pieces or is cut to allow two more rigid connecting pieces to bend along the line of the live hinge. Live hinge  20  is therefore thinner or has a smaller thickness than the walls of tip  14  and petals  16  that it joins, as best shown in  FIG. 2( c ) . Notch  22  of hinge  20  allows petals  16  to rotate downward toward each other for the cap  12  to be assembled and placed on the needle, as shown in  FIGS. 1  and  2 ( a ). Notch  22  may also be positioned on the inside surface as shown or on the outside surface. The low cost and ease of manufacturing makes live hinges suitable for disposable packaging. Plastic living hinges are typically manufactured in an injection molding operation or in a compression molding that creates all three parts, i.e., tip  14 , petals  18  and hinge  20 , at one time as a single integral part. Suitable plastic materials include, but are not limited to, polyethylene and polypropylene. Hinge  20 , tip  14  and petals  16  can also be compression molded from thermosetting or thermoplastic elastomeric materials. Core  20  is preferably made separately, or alternatively may be molded at the same time as the rest of cap  12  using known co-injection technique and can be made with a material that is different than the materials for the rest of the cap. 
         [0018]    Preferably, cap  12  is molded in the open shape shown in  FIG. 2( b )  and this open shape is at least partially set when molded, so that cap  12  remembers this open shape and at least partially returns to this open shape when a force or a retainer holding the petals together is removed. 
         [0019]    Petals  16  are secured together to the closed configuration or shape of  FIG. 2( a )  by a variety of means shown in  FIGS. 3( a )-3( c ) . A band  24 , which can be flexible or rigid, can be slid over petals  16  as shown in  FIG. 3( a )  to secure petals  16  to each other. As petals  16  are pressed toward each other, they may compress elastomeric core  18 . To remove cap  12  from the needle, band  24  is moved along direction  26  toward tip  14 . After band  24  is removed, live hinges  20  and the shape memory of molded open cap  12  push petals  16  apart in direction  28 . The compression of elastomeric core  18  provides an optional force that pushes petals  16  apart, when band  24  is removed. 
         [0020]    Cap  12  can also be attached via a number of frangible bridges to a lower ring  30 , which is attached to syringe  10 , as shown in  FIG. 2( b ) . Ring  30  is similar to the lower ring on a tamper evident seal that is connected to caps to soda bottles and condiment bottles, among others. When lower ring  30  is removed from cap  12 , for example, by a twisting motion to break the frangible bridges, in direction  30 , petals  16  open in direction  28 . Advantageously, the compression of elastomeric core  18  when released provides the force that pushes petals  16  apart. 
         [0021]    In another embodiment, cap  12  is held in the closed configuration of  FIG. 2( a )  by a number of overhanging arms  32  from syringe  10 , shown in  FIG. 3( c ) . Arms  32  secure petals  16  together. In one variation, the distal ends of arms  32  are flexible, so that cap  12  can be pulled away from syringe  10  in direction  26  and petals  16  open in direction  28 . In another variation, arms  32  are pivotable, and when the proximal ends of arms  32  are pressed together the distal ends move away from each other to release cap  12  and petals  16 . 
         [0022]    In another embodiment, cap  12  is kept in the closed configuration by wrap  33 , preferably a heat shrink wrap. Such a wrap may have scored line(s) such as the line designated by reference number  34 . Alternatively, the wrap may have a thread or the like which can also be designated by reference number  34 . The user may break or tear the wrap at scored line  34  or tear the thread  34  to release petals  16 . Advantageously, wrap  33  may extend over a portion of the barrel in syringe  10 , such that the user needs to break or tear wrap  33  in order to remove cap  12  from syringe  10 . The same motion that tears wrap  33  to allow cap  12  to be removed also releases petals  16 . 
         [0023]    Yet another embodiment is illustrated in  FIGS. 4( a )-4( d ) . Live hinge  36  is located along the longitudinal axis of cap  12 , as best shown in  FIG. 4( a ) , and only one petal  38  is necessary for each live hinge  36 . For simplicity, one live hinge  36  and one petal  38  is used and illustrated. Live hinge  36  may also have a notch running along the longitudinal direction either on the inside surface or the outside surface. Cap  12  can also be molded in the open shape shown in either  FIG. 4( c )  or  4 ( d ), and petal  38  is pressed together to from the closed configuration shown in  FIG. 4( b ) . The larger opening in petal  38 , e.g. shown in  FIG. 38 , provides a higher shape memory and therefore a higher opening force. An advantage of this embodiment is that live hinge  36  is larger and can provide more opening force. Additionally, the molded open shape is simpler to manufacture. 
         [0024]    In another embodiment, to further simplify the molding/manufacturing process tip  14  may be omitted and petal  38  can be extruded and then cut to any desired length, as illustrated in  FIG. 5 . This obviates the need to mold parts with complicated geometries. Elastomeric core  18 , which secures the tip of needle  19  of the syringe, can have a section  40  with a larger diameter and a section  42  with a smaller diameter. Petal  38  without tip  14  can be wrapped around the smaller section  42  so that the outside surface of petal  38  is flushed with the larger section  40  to give cap  12  a smooth outer surface. Wrap  33  discussed above can be used to keep cap  12  in the closed configuration of  FIG. 4( b ) . Preferably, wrap  33  also covers at least a portion of syringe  10  or all of syringe  10 . 
         [0025]    Alternatively, preferably for syringes that are not pre-filled core  18  may be omitted as long as petal  38  in the closed configuration and acting as a sheath extends safety beyond the distal end of needle  19  to prevent access to needle  19 . Wrap  33  may cover the open end of petal  38  to maintain sterility and cleanliness to needle  19 . 
         [0026]    Live hinges are optional in the embodiment of  FIGS. 4( a )-( c )  and of  FIG. 5 , because the single petal  38  itself acts as a spring when compressed to form the closed configuration. Live hinges, including notch  22 , can be included to control, e.g., lower, the spring force of petal  38 . 
         [0027]    While it is apparent that the illustrative embodiments of the invention disclosed herein fulfill the objectives stated above, it is appreciated that numerous modifications and other embodiments may be devised by those skilled in the art. Feature(s) from one embodiment can be incorporated into other embodiments. Therefore, it will be understood that the appended claims are intended to cover all such modifications and embodiments, which would come within the spirit and scope of the present invention.