Abstract:
A needle guard device mountable to a pre-filled syringe in its ready-to-fill state. The device includes a lock collar and a device shield biased to move relative to the lock collar. The lock collar interfaces with the syringe neck to attach the device to the syringe. A flexible member interconnects the lock collar and device shield. With the removal of a needle shield assembly comprising rigid and soft needle shields, the device shield is free to move proximally along the syringe neck. As the device moves proximally, rotation arms of the lock collar interact with angled cutouts in the device shield, causing the device shield to rotate relative to the lock collar disengaging one or more keys on the device shield from one or more keyways in the lock collar triggering the device shield to move from a first configuration in which the device shield is retractable to expose a syringe sharp to a second configuration in which the device shield is fixedly positioned to cover the syringe sharp.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Provisional Application No. 61/662,303, filed Jun. 20, 2012, which application is incorporated herein by reference. 
    
    
     FIELD 
     The embodiments provided herein relate generally to safety systems for syringes, and more particularly to a needle guard for a syringe that includes an automatically activated shield for covering a needle of the syringe. 
     BACKGROUND INFORMATION 
     Medication is often dispensed using a medicine cartridge, such as a glass syringe, having a barrel with a needle at one end and a plunger slidably inserted into the other end and coupled to a rubber stopper. Such cartridges are often referred to as “pre-filled syringes” because they may contain a specific dosage or volume of medication when they are initially provided, as compared to conventional syringes that are furnished empty and filled by the user before making an injection. 
     The glass syringe and rubber stopper have, for years, provided an ideal drug storage closure having unique properties of impermeability to oxygen, low extractables, biocompability, durability, etc. However, they are both formed by processes that do not lend themselves to tight geometrical tolerances. Tight tolerances were not originally needed by these devices because they were not used mechanically with other devices. 
     Due to the risk of communicable diseases, a number of syringes and adapters have been developed that are intended to prevent accidental needle sticks and/or inadvertent reuse of a syringe. Conventional passive anti-needle stick safety devices for prefilled syringes must mount to the syringe but not interfere excessively with the force required to move the plunger rod during injection nor prevent the full travel of the plunger rod. The safety mechanism necessarily must be triggered toward the end of the administration of the drug or injection (i.e., near the end of the plunger rod travel). However, since virtually all safety devices locate the syringe against the safety device at a point under the syringe finger flange, the operability of the safety device tends to be dependent on the tolerances of the syringe and stopper. 
     In addition, because conventional passive anti-needle stick safety devices for prefilled syringes tend to mount to or on the barrel of the syringe, the safety devices tend to obscure the contents of the syringe and must be applied post filling of the syringe. 
     Prefilled syringes tend to be shipped to pharmaceutical customers as ready-to-fill syringes, which are syringes that have been thoroughly cleaned inside and outside after the forming processes and attachment of a needle have been completed, and then placed in sealed tubs that are then sterilized and shipped to the pharmaceutical customers ready for filling with a medicine. The syringe tubs may contain 100 to 160 syringes, each with a geometrical spacing and access that is consistent with established syringe handling equipment. A safety device applied to the syringe must not obscure the optical inspection systems that are in place to check the syringes prior to filling them with medication. 
     Accordingly, it would be desirable to have a needle guard for a ready-to-fill syringe having the safety device triggering mechanism independent of the syringe and stopper tolerances, and that assembles to the syringe without adversely affecting the syringe position with respect to the syringe handling tub or the way the handling equipment conveys the syringes during filling and packaging nor impedes the inspection processes. 
     SUMMARY 
     The systems and methods described herein are directed to a needle guard for a syringe having the safety device triggering mechanism independent of the syringe and stopper tolerances. A contact trigger release needle guard device described herein is an anti-needle stick device designed to be attached to the distal end of a ready-to-fill syringe. The needle guard device includes a lock collar and a device shield moveable relative to the lock collar. The device shield is biased relative to the lock collar by an elastic spring coupled between the device shield and the lock collar. The lock collar interfaces with a syringe neck and recess to attach the needle guard device to the ready-to-fill syringe. With the removal of a rigid needle shield subassembly comprising rigid and soft needle shield components, the device shield is free to move proximally along the syringe neck and interact with the lock collar triggering the device shield to move relative to the lock collar from a first configuration, where the device shield is moveable to expose a syringe sharp to a second configuration where the needle is fixedly shielded or covered. 
     In use, a device user removes the rigid needle shield subassembly, inserts the syringe sharp, such as a needle, into an injection site and pushes down on the syringe past the point of initial contact of the device shield with the skin, moving the device shield proximally along the lock collar. As the device shield moves proximally along the lock collar, rotation arms of the lock collar interact with angled cutouts in the device shield causing the device shield to rotate relative to the lock collar and disengage one or more keys on the device shield from one or more keyways in the lock collar, triggering the device shield to move from a first configuration where the device shield is retractable to expose a syringe sharp, to a second configuration where the device shield is fixedly positioned to shield or cover the syringe sharp. 
     Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The details of the invention, including fabrication, structure and operation, may be gleaned in part by study of the accompanying figures, in which like reference numerals refer to like parts. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, all illustrations are intended to convey concepts, where relative sizes, shapes and other detailed attributes may be illustrated schematically rather than literally or precisely. 
         FIG. 1  is an isometric view of an exploded assembly of a safety device with a syringe. 
         FIG. 2  is an isometric view of a lock collar and a device shield after a first step (polymer injection molding—1st shot) in a process of manufacturing the integrated lock collar, device shield, and flexible interconnect part. 
         FIG. 3  is an isometric view of the lock collar, device shield, and flexible interconnect after a second step (TPE injection molding—2nd shot) in the process of manufacturing the integrated lock collar, device shield, and flexible interconnect part. 
         FIG. 4  is an isometric view of the lock collar, device shield, and flexible interconnect after a third step (clipping of the lock collar/device shield bridges) in the process of manufacturing the integrated lock collar, device shield, and flexible interconnect part. 
         FIG. 5  is an isometric view of the integrated lock collar, device shield, and flexible interconnect part assembled together with the lock collar inserted into the device shield. 
         FIG. 6  is a cross sectional view of the integrated lock collar, device shield, and flexible interconnect part assembled together with the lock collar inserted into the device shield. 
         FIG. 7  is a cross sectional view of the safety device assembled to a syringe neck with a rigid needle shield (RNS) in place prior to use. 
         FIG. 8  is a front view of a syringe with a custom neck for integration with the safety device. 
         FIG. 9  is a top view of the lock collar of the safety device. 
         FIG. 10  is an isometric view of the RNS with an integrated grip for easy removal from the safety device. 
         FIG. 11  is an isometric cross sectional view of the RNS. 
         FIG. 12  is an isometric view of the safety device fully assembled with a syringe and a plunger, and with the RNS removed. The device is depicted as pressed against the skin of a patient ready to insert the needle into the injection site. 
         FIG. 13  is a cross sectional, partial isometric view of the safety device fully assembled with a syringe, and with the RNS removed. The safety device is depicted as pressed against the skin of a patient ready to insert the needle into the injection site. 
         FIG. 14  is a cross sectional, isometric view of the device prior to inserting the needle into the injection site showing a ramp within the lock collar which device shield lock arms travel up. 
         FIG. 15  is an isometric view of the lock collar. 
         FIG. 16  is an isometric view of the safety device prior to needle insertion into the injection site with a portion of the device shield and flexible interconnect cut away. This view shows a lock collar rotation arm and its alignment with an angled cutout within the device shield. 
         FIG. 17  is a cross sectional view through the top of the safety device revealing the rotational dependence of the device shield and lock collar via a key on the device shield and a keyway within the lock collar. 
         FIG. 18  is a cross sectional isometric view of the device shield. 
         FIG. 19  is an isometric detail view of the lock collar rotation arm as it has engaged with the device shield angled cutout during needle insertion. 
         FIG. 20  is an isometric view of the safety device during needle insertion as the lock collar rotation arm has engaged with the device shield angled cutout during needle insertion. 
         FIG. 21  is an isometric, cross sectional view through the safety device during needle insertion which shows the direction of rotation of the device shield relative to the lock collar and the device shield key&#39;s ability to flex from the keyway at the point of needle insertion. 
         FIG. 22  is a, cross sectional view viewed from the proximal end through the safety device during needle insertion which shows the direction of rotation of the device shield relative to the lock collar and the device shield key&#39;s ability to flex from the keyway at the point of needle insertion. 
         FIG. 23  is an isometric view of the safety device at full needle insertion with the lock collar rotation arm at point B of the device shield angled cutout. 
         FIG. 24  is a detail view of the lock collar rotation arm at point B of the device shield angled cutout at full needle insertion. 
         FIG. 25  is an isometric, cross sectional view of the safety device after full needle insertion, showing the device shield key locked rotationally with the lock collar tab. 
         FIG. 26  is a cross sectional ( 90  degrees offset from  FIG. 18 ) isometric view of the device shield. 
         FIG. 27  is an isometric, cross sectional view of the safety device after full needle insertion, showing the device shield cutout, in place to relieve any stress on the lock collar rotation arm. 
         FIG. 28  is an isometric view of the safety device upon needle removal as a device shield lockout arm re-engages with the lock collar. 
         FIG. 29  is a detail, cross sectional view of the safety device upon needle removal as the device shield lockout arm re-engages with the lock collar. 
         FIG. 30  is a cross sectional, partial isometric view of the device after needle removal and device lockout. 
         FIG. 31  is a detail, cross sectional, isometric view of the device after needle removal and device lockout with the device shield lockout arm in lockout position. 
         FIG. 32  is a partial isometric view of an alternate lockout method embodiment with a portion of the device shield cut away to view the inside of the device. The alternate lockout method embodiment is shown in a state prior to device use. 
         FIG. 33  is a partial isometric view of an alternate lockout method embodiment prior to device use. 
         FIG. 34  is a partial isometric view of an alternate lockout method embodiment after the needle has been inserted partway into the injection site. 
         FIG. 35  is a cross sectional partial isometric view of the alternate lockout method embodiment after the needle has been inserted partway into the injection site. 
         FIG. 36  is an isometric view of a lock ring used in the alternate lockout method embodiment. 
         FIGS. 37  A and B are cross sectional partial isometric views of an alternate lockout method embodiment after the needle has been inserted fully into the injection site. 
         FIGS. 38  A and B are cross sectional partial isometric views of the alternate lockout method embodiment after the needle has been fully removed from the injection site and the device is in the locked state. 
     
    
    
     DETAILED DESCRIPTION 
     The systems and methods described herein are directed to a needle guard for a syringe having the safety device triggering mechanism independent of the syringe geometry. Turning now to the figures,  FIGS. 1-38  show embodiments of a contact trigger release needle guard. The needle guard described herein is an anti-needle stick safety device designed to be attached to the distal end of a prefilled syringe in its ready-to-fill state. As depicted in  FIG. 1 , an anti-needle stick safety device or needle guard  100  is designed to be attached to the distal end of a syringe  50  in its ready-to-fill state. The device  100  is comprised of a lock collar  10 , a device shield  20 , a flexible interconnect  30  and a rigid needle shield  40  comprised of a rigid outer component  41  and a soft inner component  42 . In a preferred embodiment, the lock collar  10 , device shield  20 , and flexible interconnect  30 . In a preferred embodiment, are produced in one injection molding process. The process consists of injection molding the lock collar  10  and device shield  20  in a first injection molding shot with a single polymer material. As depicted in  FIG. 2 , the two parts may be connected via a thin bridge  60  of material or via a runner system in what is typically known as a family mold. A second injection molding shot would consist of a flexible material such as a thermoplastic elastomer (TPE), which would produce a flexible interconnect  30  that physically connects the lock collar  10  to the device shield  20  as shown in  FIG. 3 . During the injection molding process the flexible interconnect  30  would physically bond to the lock collar  10  and device shield  20 . Alternatively, the lock collar  10  and device shield  20  may be designed such that when the flexible interconnect  30  is injection molded, a physical mechanical bond is created between the parts. As depicted in  FIG. 4 , the last step in the process is to clip off the bridge  60 . 
     As shown in  FIGS. 5 and 6 , when the safety device  100  is assembled the lock collar  10  is pushed or inserted within the device shield  20 . This step is made possible by the flexibility of the flexible interconnect  30 , which is coupled to and positioned between the lock collar  10  and device shield  20 . 
     Turning to  FIGS. 7 ,  8  and  9 , the device  100  is shown assembled to the syringe  50  via a recess  52  in the syringe neck  53  and lock collar tabs  11  located on the inner diameter of the lock collar  10 . The rigid needle shield  40  is attached to the distal end of the syringe  54 . As shown in  FIGS. 10 and 11 , the rigid needle shield  40  is comprised of an outer rigid thermoplastic  41 , and inner soft elastomeric needle shield  42 , as is currently marketed and often used on glass, pre-filled syringes to protect the needle and drug such as, e.g., the Stelmi rigid needle shield or the BD rigid needle shield. The distal end of the syringe  54  is designed to be identical to a standard 1 ml long pre-filled glass syringe. Consequently, the rigid needle shield  40  functions identically to current pre-filled syringe rigid needle shield systems, protecting both the needle sharp  51  and the contents of the syringe  50  by creating a seal between the soft needle shield component  42  and the bulbus  55  of the syringe, and the soft needle shield component  42  and the syringe sharp  51 . 
     The rigid needle shield  40  also contains a grip section  43  extending from the outer rigid portion  41 , which protrudes from the bottom of the device shield  20  as depicted in  FIG. 7 . The grip  43  is available to the user to grab and remove the rigid needle shield  40  prior to use of the syringe  50  and safety device  100 . After removal of the rigid needle shield  40 , the syringe  50  and safety device  100  is ready for drug injection. 
     Turning to  FIG. 12 , to perform an injection a user would place the distal end  28  of the device shield  20  against the injection site  70  and push the syringe  50  to insert the needle  51 . As the syringe  50  is pushed distally, the device shield  20  will travel proximally along the syringe  50 . As shown in  FIG. 13 , the flexible interconnect  30  is bonded or fixed to the distal end of the lock collar  10  and to the proximal end of device shield  20 , and, as a result, as the syringe  50  is pushed distally, the lock collar  10 , which is coupled to the syringe  50 , travels distally relative to the device shield  20  causing the flexible interconnect  30  to be stretched, thereby storing energy, and thus, acting like a spring. 
     During the initial few millimeters of travel of the device shield  20  proximally along the syringe  50 , a device shield lockout arm  22  rides up or proximally along a ramp  12  located on the lock collar  10  as shown in  FIG. 14 . Consequently, the device shield lockout arm  22  flexes and will ride up or proximally along the syringe  50  in flexion during insertion of the needle  51  into the injection site  70 . Turning to  FIGS. 15 and 16 , an angled cutout  23  is shown in the device shield  20  and a rotation arm  14  is shown on the lock collar  10 . The rotation arm  14  is aligned vertically with the beginning point (Point A) of the angled cutout  23 . As depicted in  FIGS. 17 and 18 , prior to needle  51  insertion, the lock collar  10  and device shield  20  are rotationally coupled via keys  25  axially extending along the interior of the device shield  20  and keyways  15  located on the outer periphery of the lock collar  10 . Turning to  FIGS. 19 and 20 , when the device shield  20  has traveled up or proximally along the syringe  50  a sufficient predetermined distance, such that the rotation arm  14  of the lock collar  10  reaches point A of the angled cutout  23 , the rotation arm  14 , which is in a flexed state while inside of the device shield  20 , will resile into the angled cutout  23  in the device shield  20 . As a result of the contact now made between the angled cutout surface  26  and the bottom edge  16  of the rotation arm  14 , and the continued proximal movement of the device shield  20  relative to the syringe  50 , the device shield  20  and lock collar  10  will begin to rotate relative to one another. As depicted in  FIGS. 21 and 22 , as the device shield  20  and lock collar  10  rotate relative to one another as the needle  51  is further inserted into the injection site  70 , an angled or chamfered surface  27  on the device shield key  25  and a cutout  38  within the device shield  20  allows the device shield key  25  to flex out from the keyway  15  and travel over a lock collar tab  17 . Referring to  FIGS. 23 and 24 , at the point where the lock collar rotation arm  14  reaches point B in the angled cutout  23 , the needle  51  is fully inserted into the injection site  70 , the device shield  20  cannot move up or proximally along the syringe  50  any further due to the interface between the bottom surface  16  of the rotation arm  14  and the bottom surface  29  of the angled cutout  23 , and, as shown in  FIG. 25 , the device shield  20  and lock collar  10  are fixed rotationally as the key  25  is allowed to resile into engagement with a lock collar tab  17 . It is preferable for the device shield  20  and lock collar  10  to be fixed rotationally at this point of device use, otherwise the torsion created in the flexible interconnect  30 , as a result of twisting the device shield  20  in relation to the lock collar  10  during needle  51  insertion, would tend to force the device shield  20  and lock collar  10  to resile to their original orientations relative to one another upon needle  51  removal. Such an occurrence, would tend to prevent the device shield  20  from properly locking in a shielded position upon full needle removal  51  from the injection site  70 . 
     After an injection has been given and the syringe  50  is pulled away from the injection site  70 , the stress or stored energy in the flexible interconnect  30  forces the device shield  20  to move distally back down the syringe  50 . As a result, the device shield  20  is always shielding the needle  51 , and consequently, protecting the administrator from accidentally sticking themselves with the needle  51 . Turning to  FIGS. 26 and 27 , as the device shield  20  is forced back towards the distal end of the syringe  50 , the rotation arm  14  rides in a channel  65  in the interior of the device shield  20 . The purpose of the channel  65  is to keep the rotation arm  14  from being required to flex and consequently, create a resistive friction force between it and the device shield  20  during needle  51  shielding. Furthermore, as shown in  FIGS. 28 and 29 , as the device shield  20  is forced back towards the distal end of the syringe  50  as a result of the force from the stretched flexible interconnect  30 , the device shield lockout arm  22  rides in a flexed state along the surface of the syringe  50  and then along a lip  18  in the lock collar  10 . As depicted in  FIGS. 30 and 31 , as the device shield lockout arm  22  rides distally down the lock collar lip  18  it will encounter a recess  19  in the lock collar, which it will snap into due to its flexed state. The interface between the top or proximal edge  66  of the device shield lockout arm  22  and the top or distal surface  68  of the lock collar recess  19  causes the device shield  22  to be in locked state, permanently protecting and shielding the needle  51 . The interface between the bottom of lockout arm  22  and the bottom surface of the lock collar recess  19  prevents further distal movement of the device shield  20  relative to the syringe  50 . 
     Turning to  FIGS. 32 and 33 , an alternate embodiment is shown to include a different device lockout method. A lock ring  150  is assembled to the lock collar  110  at its distal end before device use. The lock ring  150  contains two tabs  151  on each side which sit within two channels  121  within the device shield  120 . As shown in  FIG. 34 , during needle insertion the needle shield  120  moves proximally away from the injection site up the syringe  160  barrel such that the lock ring tabs  151  slide within the device shield channels  121  until the bottom surface  128  of the channels contact the lock ring tabs  151 . As the device shield  120  continues to move up the syringe  160  barrel and the needle further penetrates the injection site, the lock ring  150 , as depicted in  FIG. 35 , is carried with the device shield  120  up the shaft  112  of the lock collar  110  where it encounters a sloped ramp  114  on each side of the lock collar  110  and flexes over the sloped ramp  114 . As shown in  FIG. 36 , the lock ring  150  is shaped like the letter C which makes it flexible. Turning to  FIG. 37 , at the top of the sloped ramp  114  of the lock collar  110  includes a flat surface  115 . Once the lock ring  150  rides completely up the sloped ramp  114  it will relax back to its original shape with its bottom surface  154  resting on the flat surface  115  of the sloped ramp  114 . Two protrusions  156  (one on each side) on the lock ring  150  are now mated with and match the outer dimensions of the syringe  160  barrel. They are also in vertical alignment with the device shield lockout arms  122 . After the injection is complete and the syringe is pulled from the injection site, the device shield  120  will move distally back down the syringe  160  barrel as was described in the previous embodiment due to the elasticity and spring force generated by the flexible interconnect  130 . To lockout the safety device, the device shield lockout arms  122 , in a flexed beam state as the needle is being removed from the injection site, will transfer contact from the syringe  160  barrel to the lock ring protrusions  156 , and, as shown in  FIG. 38 , then snap into place under the protrusions  156 . Since, as shown in  FIG. 32 , the lock ring  150  is constrained vertically by the flat surface  115  of the lock collar sloped ramps  114  and the bottom surface of the lock collar lip  119 , the shield  120  will be unable to move up the syringe barrel  160 , consequently locking the device and protecting the user from an accidental needle stick. 
     In the foregoing specification, the invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention. For example, the reader is to understand that the specific ordering and combination of process actions shown in the process flow diagrams described herein is merely illustrative, unless otherwise stated, and the invention can be performed using different or additional process actions, or a different combination or ordering of process actions. As another example, each feature of one embodiment can be mixed and matched with other features shown in other embodiments. Features and processes known to those of ordinary skill may similarly be incorporated as desired. Additionally and obviously, features may be added or subtracted as desired. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.