Abstract:
A safety needle assembly is provided herein having a hub; a needle fixed to the hub; a shield; a tab; a spring disposed between the shield and the hub configured to bias the shield distally; and, a clip disposed between the hub and the shield, the clip having a notch formed thereon shaped to permit passage therethrough of the tab. The clip and the tab releasably retain the shield in a first locked state against the biasing force of the spring thereby limiting distal movement of the shield relative to the hub; yet, in the first locked state, the shield is movable proximally relative to the hub. In the first locked state, the notch is spaced from the tab. The clip and the tab are relatively displaceable so as to align the notch with the tab and release the shield from the first locked state thereby allowing the shield to move distally, relative to the hub, to a second shielded state. In the second shielded state, the distal end of the needle is covered by the shield. Advantageously, with the subject invention, a passive safety needle assembly may be provided which requires few parts and is reliable.

Description:
FIELD OF THE INVENTION 
     This invention relates to needle assemblies, more particularly, to safety needle assemblies. 
     BACKGROUND OF THE INVENTION 
     Pen injectors are known in the prior art and typically include a pen needle for insertion into a patient to allow proper drug administration. Such pens may be disposable, containing a single dose of a drug, or reusable, containing a single dose or more of a drug. The pen needle includes a double-ended needle with a distal end formed for insertion into a patient and a proximal end formed for insertion into a drug vial or cartridge located inside a pen injector body. The pen needle should be single-use and replaced with each administered dose. 
     Safety pen needle assemblies have been developed in the prior art which shield a pen needle after use. Typically, with this arrangement, after an injection, a lock mechanism locks a shield over the patient end of a safety pen needle and prevents reusage. The lock mechanisms of current safety pen needle assemblies implicate various considerations, including cost and manufacturing. Reliability is highly desired. 
     SUMMARY OF THE INVENTION 
     A safety needle assembly is provided herein having a hub; a needle fixed to the hub; a shield; a tab; a spring disposed between the shield and the hub configured to bias the shield distally; and, a clip disposed between the hub and the shield, the clip having a notch formed thereon shaped to permit passage therethrough of the tab. The clip and the tab releasably retain the shield in a first locked state against the biasing force of the spring thereby limiting distal movement of the shield relative to the hub; yet, in the first locked state, the shield is movable proximally relative to the hub. In the first locked state, the notch is spaced from the tab. The clip and the tab are relatively displaceable so as to align the notch with the tab and release the shield from the first locked state thereby allowing the shield to move distally, relative to the hub, to a second shielded state. In the second shielded state, the distal end of the needle is covered by the shield. Advantageously, with the subject invention, a passive safety needle assembly may be provided which requires few parts and is reliable. 
     As used herein, the term “distal”, and derivatives thereof, refers to a direction towards a patient during use. The term “proximal”, and derivatives thereof, refers to a direction away from a patient during use. 
     These and other features of the invention will be better understood through a study of the following detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a perspective view of a safety needle assembly formed in accordance with the present invention; 
         FIGS. 2-16  depict an embodiment of the subject invention where the clip is mounted to the shield; and, 
         FIGS. 17-27  depict an embodiment of the subject invention where the clip is mounted to the hub. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to the Figures, a safety needle assembly  10  is depicted. The assembly  10  is useable with various injectors but is particularly well-suited for use as a safety pen needle assembly with pen injectors. The assembly  10  generally includes a hub  12  fixed to a needle  14 , a spring  16 , a shield  18 , a clip  20 , and a tab  22 , as shown in  FIGS. 1-5 . 
     The hub  12  is generally tubular and includes a cross-piece  24  which extends at least partially across the interior thereof. The needle  14  passes through and is fixed to the cross-piece  24  in any known manner (e.g., being fixed by adhesive in opening  25  formed in the cross-piece  24  ( FIG. 4 )). The needle  14  includes a proximal end  26 , located proximally of the cross-piece  24 , and a distal end  28 , located distally of the cross-piece  24  ( FIG. 6 ). The distal end  28  is formed for insertion into a patient. 
     The shield  18  is disposed distally of the cross-piece  24 . The shield  18  preferably is made of a polymeric material (e.g., thermoplastic) and preferably telescoped inside the hub  12 . In this manner, the hub  12  is exposed for handling by a user, particularly in mounting the assembly  10  onto an injector body. Alternatively, the hub  12  may sit inside the shield  18 . However, this arrangement may be less desired in that the hub  12  may be obscured for mounting. It is desired to avoid contact with the shield  18  during mounting or dismounting of the assembly  10 . 
     The spring  16  is a biasing mechanism, preferably a compression spring, that sits between the shield  18  and the hub  12 , preferably between the shield  18  and the cross-piece  24 . The spring  16  is configured to urge the shield  18  distally away from the hub  12 . 
     The clip  20  is disposed between the hub  12  and the shield  18 . The clip  20  is arcuate, and, preferably, the clip  20  is a continuous or discontinuous annular ring having an inner opening  30  sized to permit passage therethrough of the shield  18 . 
     The clip  20  is disposed so as to be fixed relative to the hub  12  or the shield  18 . Preferably, and with reference to  FIGS. 2 and 6 , the shield  18  includes a groove  32  in which the clip  20  may be seated. Preferably, the shield  18  is disposed to telescope interiorly of the hub  12  with the clip  20  being located on an exterior face of the shield  18 . With this arrangement, the inner opening  30  is preferably slightly larger than the groove  32  so that the clip  20  may move or rotate about the shield  18 . In this manner, the clip  20  is rotatable about the shield  18  but not axially movable along the length of the shield  18 . The clip  20  is preferably made of plastic. As will be appreciated by those skilled in the art, the shield  18  may be configured to telescope exteriorly of the hub  12 , as shown in  FIGS. 13-16 . With this arrangement, the groove  32  is located on an interior face of the shield  18  with the clip  20  being seated therein. 
     In the preferred arrangement of  FIG. 2 , the clip  20  is seated in the groove  32  and movable relative to the hub  12  with the shield  18 . Alternatively, and with reference to  FIGS. 17-27 , a hub groove  34  may be formed in the hub  12 . With this arrangement, the clip  20  may be seated in the hub groove  34  and move or rotate relative to the hub  12  but not move axially relative to the hub  12 . The shield  18  is movable with this arrangement relative to the hub  12  and the clip  20 . 
     The tab  22  is located depending on where the clip  20  is seated. In the preferred arrangement with the clip  20  seated in the groove  32  on the shield  18 , the tab  22  is preferably formed on the hub  12 . In the alternative, with the clip  20  seated in the hub groove  34  of the hub  12 , the tab  22  is preferably formed on the shield  18 . A notch  36  is formed on the clip  20  configured to allow passage of the tab  22  therethrough. 
     It is noted that one or more of the tabs  22  may be utilized with a corresponding number of the notches  36  being provided. By way of non-limiting example, and with reference to  FIGS. 4 and 5 , three of the tabs  22  may be provided. Correspondingly, three of the notches  36  may be provided on the clip  20  ( FIG. 3 ). The notches  36  may be formed through the clip  20  so as to form a break in the clip  20  and/or the notches  36  may be formed of limited depth, as shown in  FIG. 3 . It is preferred that one of the notches  36  be formed through the clip  20  thus providing the clip  20  with deformable resilience that facilitates mounting the clip  20  about the shield  18 . With reference to  FIGS. 13-16 , one of the tabs  22  may be utilized. For illustrative purposes, any reference herein to a singular of the tabs  22  or the notches  36  is not limiting and is intended to cover arrangements of one or more of the components. 
     The clip  20  and the tab  22  coact together to releasably retain the shield  18  in a first locked state against the biasing force of the spring  16  thereby limiting distal movement of the shield  18  relative to the hub  12 . Specifically, in the first locked state, the notch  36  is spaced from the tab  22  so as to not be in alignment therewith ( FIGS. 6 and 17 ). The clip  20  and the tab  22  are relatively displaceable such that the notch  36  may be aligned with the tab  22 . With the notch  36  being aligned with the tab  22 , the shield  18  is released from the first locked state with the shield  18  being able to move distally, relative to the hub  12 , under force of the spring  16  to a second shielded state where the distal end  28  of the needle  14  is covered by the shield  18 . The specifics of this process may be altered depending on how the clip  20  is retained in the assembly  10 . 
     With reference to  FIGS. 6-12 , operation of the assembly  10  is shown with the clip  20  being seated in the shield groove  32 . With this arrangement, the clip  20  moves axially relative to the hub  12 . 
     With reference to  FIG. 6 , the tab  22  is formed on the hub  12 . A channel  38  is formed in the shield  18  in which the tab  22  extends.  FIG. 6  depicts the first locked state with the notch  36  being spaced from the tab  22 . With the tab  22  being located distally of the clip  20 , the interengagement of the tab  22  and the clip  20  limits distal movement of the shield  18  under force of the spring  16 . The shield  18 , however, is free to move proximally. In this manner, the needle  14 , particularly the distal end  28 , may be sufficiently exposed to conduct an injection. Depending on the spacing and arrangement of the various elements of the assembly  10 , the shield  18  may be positioned to initially cover, i.e., cover in the first locked state, any degree of the needle  14 , including covering the entire needle  14 . It may be desired, as shown in  FIG. 6 , to have a small extent of the needle  14  from the distal end  28  to be initially exposed in the first locked state so that priming of the needle  14  may be visually inspected. 
     To facilitate assembly of the assembly  10 , the tab  22  may be located on a cantilevered arm  27  formed in the hub  12 . The resilience of the cantilevered arm  27  allows for radially outwardly deflection of the tab  22 , along with the cantilevered arm, in inserting the clip  20  past the tab  22  to the position shown in  FIG. 6 . 
     Movement of the clip  20 , particularly rotation, is required to align the notch  36  with the tab  22  so as to release the shield  18  from the first locked state. As will be appreciated by those skilled in the art, any known arrangement for achieving rotation of the clip  20  consistent with the subject invention may be utilized. By way of non-limiting example, and with reference to  FIGS. 3 and 4 , complementary ramped surfaces  40 ,  42  may be provided on the hub  12  and the clip  20 , respectively, which cooperatively cause the clip  20  to rotate upon sufficient proximal movement of the shield  18  relative to the hub  12 . Preferably, in the first locked state, a protrusion  44  formed on the hub  12  extends into a recess  46  formed on the clip  20  ( FIG. 7 ). The interengagement of the protrusion  44  and the recess  46  limits rotational movement of the clip  20  relative to the shield  18 , particularly in the rotational direction necessary to align the notch  36  with the tab  22 . With sufficient proximal movement of the shield  18 , as shown in  FIG. 8 , the ramped surfaces  40 ,  42  are brought together. In addition, the recess  46  is moved clear of the protrusion  44 . With sufficient proximal movement, the ramped surfaces  40 ,  42  cause movement of the clip  20 , e.g., in the form of rotation as represented by the arrow in  FIG. 8 . As shown in  FIG. 9 , with sufficient rotation, the notch  36  is caused to align with the tab  22  so that the notch  36  may pass distally thereover under force of the spring  16  causing distal movement of the shield  18 . 
     Alignment of the tab  22  and the notch  36  permits the shield  18  to be released from the first locked state. With rotation of the clip  22 , the recess  46  is out of alignment with the protrusion  44 . To permit distal movement of the shield  18  and avoidance of interengagement of the protrusion  44  with the clip  20 , a by-pass channel  45  ( FIG. 3 ) may be formed on the clip  20  sized and positioned to pass over the protrusion  44  during distal movement of the shield  18 . 
     With sufficient distal movement of the shield  18 , a secondary ramped surface  43 , formed on the clip  20 , comes into engagement with a complementary second ramped surface  48  formed on the hub  12  ( FIG. 10 ). The secondary ramped surfaces  43  and  48  are configured to cause reverse rotation of the clip  20  back towards its initial state as found in the first locked state. With this rotation, the notch  36  comes out of alignment with the tab  22 . As such, the tab  22  is located proximally of the clip  20  and spaced from the notch  36 , as shown in  FIG. 11 . In addition, a secondary protrusion  50 , formed on the hub  12 , is urged into the recess  46  so as to prevent subsequent movement of the clip  20  thereafter ( FIG. 12 ). 
     With reference to  FIG. 9 , the channel  38  is shown as travelling past the tab  22 . The channel  38  includes a proximal end  52  (best shown in  FIG. 6 ). With sufficient distal movement of the shield  18 , the tab  22  is urged to the proximal end  52 . The interengagement of the tab  22  and the proximal-end  52  limits further distal movement of the shield  18  under force of the spring  16 . In addition, with the clip  20  being rotated back, as shown in  FIG. 11 , the tab  22  is located proximally of the clip  20 . Proximal movement of the shield  18  is limited due to the interengagement of the tab  22  with the clip  20 . With limited distal and proximal movement, the shield  18  may be locked in the second shielded state, particularly with the shield  18  covering the distal end  28  of the needle  14 . 
     With reference to  FIGS. 13-16 , the device  10  is shown with the shield  18  being configured to telescope exteriorly of the hub  12 . As shown in  FIG. 14 , the groove  32  is formed interiorly of the shield  18  and, as shown in  FIGS. 15 and 16 , the tab  22  and the ramped surfaces  42 ,  48  are located exteriorly of the hub  12 . Also, as shown in  FIG. 13 , features on the clip  20  are located interiorly along the inner opening  30 . 
     With reference to  FIGS. 17-27 , the device  10  is shown where the clip  20  is mounted into the hub groove  34 . With this arrangement, the shield  18  may be configured to telescope over the hub  12  with the tab  22  and other elements formed on the hub  12  (e.g., the ramped surfaces  42 ,  48 ) being located on an external face thereof, or the shield  18  may be configured to telescope within the hub  12  as shown in  FIGS. 17-26 , with the tab  22  and other elements being located on an internal face of the hub  12 . In addition, the hub groove  34  may be located interiorly of the shield  18  or exteriorly of the shield  18  ( FIGS. 17-27 ). The clip  20  is correspondingly located with the features thereof being configured to cooperatively interact as described below. 
     With reference to  FIGS. 17-26 , operation of the assembly  10  is shown with the clip  20  being seated in the hub groove  34 . With this arrangement, the clip  20  does not move axially relative to the hub  12 . 
     With reference to  FIG. 17 , the tab  22  is formed on the shield  18 , and the channel  38  is formed in the hub  12  in which the tab  22  extends.  FIG. 17  depicts the first locked state with the notch  36  being spaced from the tab  22 . With the tab  22  being located proximally of the clip  20 , the interengagement of the tab  22  and the clip  20  limits distal movement of the shield  18  under force of the spring  16 . The shield  18 , however, is free to move proximally. In this manner, the needle  14 , particularly the distal end  28 , may be sufficiently exposed to conduct an injection. Depending on the spacing and arrangement of the various elements of the assembly  10 , the shield  18  may be positioned to initially cover, i.e., cover in the first locked state, any degree of the needle  14 , including covering the entire needle  14 . It may be desired, as shown in  FIG. 17 , to have a small extent of the needle  14  from the distal end  28  to be initially exposed in the first locked state so that priming of the needle  14  may be visually inspected. 
     Movement of the clip  20 , particularly rotation, is required to align the notch  36  with the tab  22  so as to release the shield  18  from the first locked state. As will be appreciated by those skilled in the art, any known arrangement for achieving rotation of the clip  20  consistent with the subject invention may be utilized. By way of non-limiting example, and with reference to  FIGS. 21-26 , the complementary ramped surfaces  40 ,  42  may be provided on the shield  18  and the clip  20 , respectively, which cooperatively cause the clip  20  to rotate upon sufficient proximal movement of the shield  18  relative to the hub  12 . Preferably, in the first locked state, the protrusion  44 , formed on the shield  18 , extends into the recess  46  formed on the clip  20 . The interengagement of the protrusion  44  and the recess  46  limits the movement of the clip  20  relative to the shield  18 . With proximal movement of the shield  18 , as shown in  FIGS. 22 and 23 , the ramped surfaces  40 ,  42  are brought together, and the protrusion  44  is moved clear of the recess  46 . With sufficient proximal movement, the ramped surfaces  40 ,  42  cause movement of the clip  20 , e.g., in the form of rotation. As shown in  FIG. 24 , with sufficient rotation, the notch  36  is caused to align with the tab  22  so that the tab  22  may pass distally therethrough under force of the spring  16 . Alignment of the tab  22  and the notch  36  permits the shield  18  to be released from the first locked state. 
     With sufficient proximal movement of the shield  18 , the secondary ramped surface  43 , formed on the clip  20 , comes into engagement with the complementary second ramped surface  48  formed on the shield  18 . The secondary ramped surfaces  43  and  48  are configured to cause reverse rotation of the clip  20  back towards its initial state as found in the first locked state. With this rotation, the notch  36  comes out of alignment with the tab  22 . As such, the tab  22  is located distally of the clip  20  and spaced from the notch  36 . In addition, the secondary protrusion  50 , formed on the shield  18 , is urged into the recess  44  so as to prevent subsequent movement of the clip  20  thereafter. 
     With reference to  FIGS. 18-20 , the tab  22  is shown as travelling along the length of the channel  38 . After sufficient proximal movement of the shield  18 , as shown in  FIG. 18 , the tab  22  and the notch  36  are caused to come into alignment and shield  18  is urged distally under force of the spring  16 . The tab  22  is urged to the distal end  52  of the channel  38 . The interengagement of the tab  22  and the distal end  52  limits further distal movement of the shield  18  under force of the spring  16 . In addition, with the clip  20  being rotated back, as shown in  FIG. 20 , the tab  22  is located distally of the clip  20 . Proximal movement of the shield  18  is limited due to the interengagement of the tab  22  with the clip  20 . With limited distal and proximal movement, the shield  18  may be locked in the second shielded state, particularly with the shield  18  covering the distal end  28  of the needle  14 . 
     The clip  20  and the hub  12  and/or the shield  18  may be formed with cooperating features which limit the extent of movement of the clip  20 . For example, with reference to  FIGS. 17 and 18 , the clip  20  may be formed with a raised shoulder  54  positioned and located to engage a step  56  located on the hub  12  and/or the shield  18 . The interengagement of the raised shoulder  54  and the step  56  limits the extent of movement of the clip  20 , e.g., limiting movement to obtain alignment of the notch  36  and the tab  22  ( FIG. 18 ). 
     The hub  12  may be provided with features  58  ( FIG. 17 ) for mounting onto an injector, such as the body of a pen injector. The features  58  are preferably located proximally of the cross-piece  24 . The features  58  may include threads and/or surface configuration (e.g., a Luer taper) for mounting onto an injector body. Alternatively, the hub  12  may be formed unitarily with or as a component of an injector body with the assembly  10  being pre-mounted thereto. This arrangement may be used for a single dose injector where replacement of the assembly  10  is not of concern.