Abstract:
A safety carpule system with integral retractable needle includes a piston element disposed between a needle hub assembly and a plunger element, each being axially slideable within a cylindrical housing. A medication-filled fluid chamber is defined between the plunger element and the piston element. The piston element is forced to into a fluid release position by way of an increase in fluid pressure within the fluid chamber, which in turn is caused by actuation of the plunger element toward the needle hub assembly by way of a syringe plunger rod. When the piston element is in fluid release position, the medication is able to flow from the fluid chamber through the needle as the syringe plunger rod is further compressed. Once the carpule system is spent, the piston element is latchably engaged by both the needle hub assembly and the plunger element, thus allowing the needle to be fully retracted into the housing upon return of the syringe plunger rod to its extended position. The spent carpule system with retracted needle is then conveniently removable from the syringe barrel for safe handling and disposal.

Description:
RELATED APPLICATIONS 
       [0001]    Not applicable. 
       TECHNICAL FIELD 
       [0002]    The present invention relates generally to medication carpules adapted to be used in connection with medical and dental syringe systems. More particularly, the invention concerns a disposable carpule system with an integral retractable needle, wherein medication can be dispensed from the carpule and the needle retracted from exposure by way of the syringe plunger rod. 
       BACKGROUND OF THE INVENTION 
       [0003]    Disposable carpules filled with a liquid medication are commonly used in connection with medical and dental syringe systems. In many such conventional systems, after the medication is dispensed, the injection needle remains dangerously exposed, either as part of the spent carpule or as a component attached to the syringe barrel. As a result, the used needle of a conventional injection system must typically be recapped or cautiously removed from the syringe, and handled and disposed of with extreme care. Those in the art recognize the need for a safer and more convenient medication carpule system, particularly one that is pre-filled with a selected liquid medication, includes the injection needle as an integral part of a carpule system, and in which the injection needle can be easily retracted from unsafe exposure once the medication is dispensed and prior to removal of the carpule system from the syringe. 
       SUMMARY OF THE INVENTION 
       [0004]    By way of summary, a safety carpule system with integral retractable needle generally includes a housing element, a needle hub assembly, a plunger element and a piston element. The housing element is substantially cylindrical and includes a first end, a second end and a main bore extending axially therebetween. The main bore has a radial wall. The needle hub assembly includes a needle element extending through a hub element. The needle hub assembly is axially transportable within the main bore between an injection position and a retracted position. A forward portion of the needle element extends outwardly of the first end when the needle hub assembly is in its injection position. The forward portion of the needle hub assembly is protected entirely within the housing element when the needle hub assembly is in its retracted position 
         [0005]    The plunger element is in sealing engagement with the main bore and is axially actuatable therewithin between a ready position, a capture position and a safety position. The piston element includes a diaphragm member and is disposed within the main bore generally between the needle hub assembly and the plunger element. A fluid chamber is generally defined by the volume within the main bore between the plunger element and the diaphragm member. The piston element is in sealing engagement with the radial wall and is axially movable from a fluid retaining position to a fluid release position. This axial movement occurs by way of an increase in a fluid pressure within the fluid chamber resulting from the actuation of the plunger element from its ready position toward its capture position. The piston element prevents fluid communication between the fluid chamber and the needle element when in its fluid retaining position. The diaphragm member is punctured and allows fluid communication between the fluid chamber and the needle element when the piston element is in its fluid release position. The piston element is simultaneously latchingly engageable by the needle hub assembly and the plunger element when the plunger element is in its capture position. As a result, the actuation of the plunger element from its capture position to its safety position results in the needle hub assembly being transported from its injection position to its retracted position. 
         [0006]    The detailed description of embodiments of the safety carpule system with integral retractable needle is intended to serve merely as examples, and is in no way intended to limit the scope of the appended claims to these described embodiments. Accordingly, modifications to the embodiments described are possible, and as will be clearly understood by those skilled in the art, the invention may be practiced in many different ways than the embodiments specifically described below, and still remain within the scope of the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Further advantages of the present invention may become apparent to those skilled in the art with the benefit of the following detailed description of the preferred embodiments and upon reference to the accompanying drawings in which: 
           [0008]      FIG. 1  is a diagrammatic perspective view of an embodiment of a safety carpule system and an associated syringe assembly prior to insertion of the safety carpule system into the breech of the syringe barrel; 
           [0009]      FIG. 2  is a further diagrammatic perspective view of the system and assembly shown in  FIG. 1 ; 
           [0010]      FIG. 3  is a diagrammatic perspective view of a safety carpule system and an associated syringe assembly after the insertion of the safety carpule system into the breech of the syringe barrel, the plunger element being in ready position; 
           [0011]      FIG. 4  is a diagrammatic perspective view of the system and assembly shown in  FIG. 3 , but in which the safety cap has been removed; 
           [0012]      FIG. 5  is a diagrammatic perspective view of the system and assembly shown in  FIG. 4 , but in which the plunger element has been actuated from the ready position to the capture position and the medication has been dispensed; 
           [0013]      FIG. 6  is a diagrammatic perspective view of the system and assembly shown in  FIG. 5 , but in which the plunger element has been actuated from the capture position to the safety position, thereby transporting the needle hub assembly to the retracted position; 
           [0014]      FIG. 7  is a diagrammatic perspective view of the system and assembly shown in  FIG. 6 , but in which the safety carpule system has been removed from the breech of the syringe barrel and the needle hub assembly remains in the retracted position by way of the safety catch element; 
           [0015]      FIG. 8  is a diagrammatic exploded view of an embodiment of a syringe assembly adapted to receive and operate an embodiment of a safety carpule system; 
           [0016]      FIG. 9  is a diagrammatic exploded view of an embodiment of a safety carpule system; 
           [0017]      FIG. 10  is a diagrammatic enlarged view of detail  10  in  FIG. 1 ; 
           [0018]      FIG. 11  is a diagrammatic enlarged view of detail  11  in  FIG. 2 ; 
           [0019]      FIG. 12  is a diagrammatic perspective view of an embodiment of a hitch element of a syringe plunger rod; 
           [0020]      FIG. 13  is a diagrammatic top view of the hitch element shown in  FIG. 12 ; 
           [0021]      FIG. 14  is a diagrammatic cross-sectional view taken along line  14 - 14  of  FIG. 13 ; 
           [0022]      FIG. 15  is a diagrammatic perspective view of an embodiment of a needle hub assembly; 
           [0023]      FIG. 16  is a diagrammatic cross-sectional view of the needle hub assembly shown in  FIG. 15 ; 
           [0024]      FIG. 17  is a diagrammatic exploded view of an embodiment of a plunger element with a plunger o-ring; 
           [0025]      FIG. 18  is a diagrammatic side view of the plunger element shown in  FIG. 17 , but in assembled form; 
           [0026]      FIG. 19  is a diagrammatic cross-sectional view taken along line  19 - 19  of  FIG. 18 ; 
           [0027]      FIG. 20  is a diagrammatic side view of an embodiment of a safety catch element; 
           [0028]      FIG. 21  is a diagrammatic perspective view of the safety catch element shown in  FIG. 20 ; 
           [0029]      FIG. 22  is a diagrammatic exploded view of an embodiment of a piston element with a piston o-ring; 
           [0030]      FIG. 23  is a diagrammatic end view of the piston element shown in  FIG. 22 , but in assembled form; 
           [0031]      FIG. 24  is a diagrammatic side view of the piston element shown in  FIG. 23 ; 
           [0032]      FIG. 25  is a diagrammatic cross-sectional view taken along line  25 - 25  of  FIG. 24 ; 
           [0033]      FIG. 26  is a diagrammatic partial cross-sectional view of the embodiment shown in  FIG. 3 , wherein the plunger element is in the ready position, the piston element is in the fluid retaining position, and the needle hub element is in the injection position; 
           [0034]      FIG. 27  is a diagrammatic partial cross-sectional view similar to that of  FIG. 26 , but wherein the plunger element has been partially actuated from the ready position toward the capture position, thereby increasing the fluid pressure within the fluid chamber and forcing the piston element into fluid release position; 
           [0035]      FIG. 28  is a diagrammatic partial cross-sectional view similar to that of  FIG. 27 , but wherein the plunger element has been fully actuated to the capture position; and 
           [0036]      FIG. 29  is a diagrammatic partial cross-sectional view similar to that of  FIG. 28 , but wherein the plunger element has been fully actuated from the capture position to the safety position, thereby resulting in the needle hub assembly being transported from the injection position and secured in the retracted position. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0037]    Referring now to the drawings, like reference numerals designate identical or corresponding features throughout the several views. 
         [0038]    Throughout the various figures, embodiments of a safety carpule system with integral retractable needle are shown generally at  100 . A safety carpule system  100  may generally comprise a housing element  102 , a needle hub assembly  112 , a plunger element  120  and a piston element  122 . A housing element  102  may be substantially cylindrical and include a first end  104 , a second end  106  and a main bore  108  extending axially therebetween. The main bore  108  has a radial wall  110 . As illustrated, for example, in  FIGS. 2 ,  3 ,  7  and  8 , certain preferred embodiments of a safety carpule system  100  are adapted to be laterally loaded into and laterally unloaded from a breech-loadable syringe assembly  156 . A breach-loadable syringe assembly  156  may have a syringe plunger rod  128  with a thumb ring  174 , a syringe body  170 , a slider element  176 , and a syringe barrel  162  with a breech opening  168  and a proximal end  164 . The breech opening  168  is typically adapted to substantially laterally receivingly engage the housing element  102 . 
         [0039]    A needle hub assembly  112  may include a hub element  114  and a needle element  116  extending generally through the hub element  114 . The needle hub assembly  112  is axially transportable within the main bore  108  between an injection position (as shown, for example, in  FIG. 26 ) and a retracted position (as shown, for example, in  FIG. 29 ). A forward portion  118  of the needle element  116  typically extends outward of the first end  104  when the needle hub assembly  112  is in the injection position. The forward portion  118  of the needle element  116  is typically disposed entirely within the housing element  102  when the needle hub assembly  112  is in the retracted position. As illustrated, for example, in  FIGS. 16 and 26 , in preferred embodiments, the housing element  102  includes a hub seat  152  for engaging a shoulder portion  154  of the hub element  114  to restrict axial movement of the hub element  114  outward of the first end  104  when the needle hub assembly  112  is in the injection position. 
         [0040]    A plunger element  120  is adapted to be in sealing engagement with the main bore  108  and axially actuatable therewithin between a ready position (as shown, for example, in  FIG. 26 ), a capture position (as shown, for example, in  FIG. 28 ) and a safety position (as shown, for example, in  FIG. 29 ). In particular embodiments of a safety carpule system  100 , the ready position and the safety position may be substantially the same. As illustrated, for example, in  FIGS. 2 ,  3  and  7 , certain preferred embodiments of a safety carpule system  100  are adapted to be laterally loaded into and laterally unloaded from a breech-loadable syringe assembly  156  having a syringe plunger rod  128  which is adapted to releasably engage the plunger element  120  such that the axial actuation of the plunger element  120  can be performed, typically exclusively, by way of the syringe plunger rod  128 . As illustrated, for example, in  FIGS. 2 and 11 , this releasable engagement may be by way of, for example, relative lateral movement between an embodiment of a safety carpule system  100  and the syringe assembly  156 . Put another way, the releasable engagement may be achievable by way of relative lateral movement between the syringe plunger rod  128  and the plunger element  120 . Further, particular embodiments of a syringe assembly  156  adapted for use with particular embodiments of a safety carpule system  100  may comprise a hitch element  158 . The hitch element  158  may be, for example, threadably connectable to the end of the syringe plunger rod  128 . This hitch element  158 , or similar structure, may be adapted to facilitate the releasable engagement between the syringe plunger rod  128  and the syringe rod engagement portion  132  of the plunger element  120 . This engagement may have, for example, a releasable snap-fit. 
         [0041]    A piston element  122  may include a diaphragm member  124 , which may be formed (for example, molded) integrally or non-integrally with the piston element  122 . The diaphragm member  124  is not limited to being a thin membrane, but can generally be, for example, any wall structure which is susceptible to being pierced or breached. The piston element  122  is typically adapted to be disposed within the main bore  108  and located generally between the needle hub assembly  112  and the plunger element  120 . A fluid chamber  126  is generally defined by the volume within the main bore  108  between the plunger element  120  and the diaphragm member  124 . The fluid chamber  126  is designed to be substantially filled with a liquid medication, such as an anesthetic. The piston element  122  is adapted to be in sealing engagement with the radial wall  110  and axially movable from a fluid retaining position (as shown, for example, in  FIG. 26 ) to a fluid release position (as shown, for example, in  FIG. 27 ) by way of an increase in a fluid pressure within the fluid chamber  126  resulting from the actuation of the plunger element  120  from the ready position toward the capture position. 
         [0042]    Embodiments of a safety carpule system  100  are also envisioned in which the hub element  114  is in sealing engagement with the radial wall  110 . In such embodiments, the piston element  122  may be in sealing engagement with the radial wall  110  by way of, for example, sealing engagement with an annular wall (not shown) of the hub element  114 . Additionally, in further such embodiments, the piston element  122  may be substantially defined by the diaphragm member  124 . 
         [0043]    As illustrated, for example, in  FIG. 26 , the piston element  122  prevents fluid communication between the fluid chamber  126  and the needle element  116  when the piston element  122  in the fluid retaining position. Conversely, as illustrated, for example, in  FIG. 27 , the diaphragm member  124  is punctured and allows fluid communication between the fluid chamber  126  and the needle element  116  when the piston element  122  is in the fluid release position. As illustrated, for example, in  FIG. 27 , in certain preferred embodiments of a safety carpule system  100 , the diaphragm member is punctured by a rearward portion  150  of the needle element when the piston element  122  is in the fluid release position. In typical preferred embodiments of a safety carpule system  100 , the hub element  114  does not have to be in sealing engagement with the radial wall  110 , because the hub element  114  is typically not subject to direct exposure to liquid medication from the fluid chamber  126 . 
         [0044]    In certain embodiments of a safety carpule system  100 , the respective sealing engagements may be by way of a plunger o-ring  146  radially disposed about the plunger element  120  and a piston o-ring  148  radially disposed about the piston element  122 . Depending on the particular embodiment, the o-rings may or may not be formed (for example, molded) integrally with the plunger element  120  or the piston element  122 , respectively. It is envisioned, for example, that in particular embodiments of a safety carpule system  100 , one or both of the plunger element  120  and the piston element  122  may be made of a material which has sufficient sealing characteristics to sealingly engage the radial wall  110  of the main bore  108  without the need to incorporate o-rings manufactured as separate components. 
         [0045]    Turning now to  FIGS. 28 and 29  for illustration, the piston element  122  is simultaneously latchingly engageable by the needle hub assembly  112  and the plunger element  120  when the plunger element  120  is in the capture position such that actuation of the plunger element  120  from the capture position to the safety position results in the needle hub assembly  112  being transported from the injection position to the retracted position.  FIG. 29  illustrates the needle hub assembly in a retracted position. The term “simultaneous latchingly engageable” does not mean that the respective latching engagements necessarily occur at the same time. In fact, in many preferred embodiments (such as, for example, the embodiment illustrated in operation between  FIGS. 26 through 29 ), these latching engagements are neither initiated or completed simultaneously. Rather, the latching engagements of the piston element  122 , once completed, may be maintained simultaneously. 
         [0046]    In particular embodiments of a safety carpule system  100 , the needle hub assembly  112  may include a first piston engagement portion  130 . Similarly, the plunger element  120  may include a syringe rod engagement portion  132  and a second piston engagement portion  134 , and the piston element  122  may include a hub engagement portion  136  and a plunger engagement portion  138 . The syringe rod engagement portion  132  is for releasable engagement by a syringe plunger rod  128 . The first piston engagement portion  130  is for latchable engagement with the hub engagement portion  136 . The second piston engagement portion  134  is for latchable engagement with the plunger engagement portion  138 . The term “latchable engagement” is generally intended to mean that once respective components are engaged (i.e., connected to each other), they remain engaged even when one of the respective components is then pulled in an axial direction opposite of the co-engaged component, for example along the main bore  108 . Such an engagement may be established, for example, by way of a male-female frictional interface, ball and socket, annular snap, cantilever snap, the like, or a variation or combination thereof. 
         [0047]    It is contemplated that the various engagement portions described herein may be initially formed integrally with or separately from the respective elements to which they are fixedly associated. For example, in  FIGS. 9 and 17 , the syringe rod engagement portion  132  is shown as separately-formed from the plunger element  120 . However, in certain embodiments, the syringe rod engagement portion  132  may be formed integrally with the plunger element  120 . 
         [0048]    One example of an embodiment of a safety carpule system  100  with male-female type latching engagement is illustrated by the embodiments shown in the various figures. Turning to  FIG. 28  for example, the first piston engagement portion  130  may be adapted for penetrating and thereby latchable engagement with the hub engagement portion  136 . Similarly, the second piston engagement portion  134  may be adapted for penetrating and thereby latchable engagement with the plunger engagement portion  138 . 
         [0049]    Certain embodiments of a safety carpule system  100  may further comprise a safety catch element  140  adapted to be affixed to the housing element  102  at generally the second end  106  for latchingly engaging a catch detent  142  of the plunger element  120  upon the actuation of the plunger element  120  from the capture position (as shown, for example, in  FIG. 28 ) into the safety position (as shown, for example, in  FIG. 29 ) and thereby restricting the plunger element  120  from axial movement from the safety position toward the first end  104 . 
         [0050]    Embodiments of the safety carpule system  100  typically further comprise a safety cap  144  for removably engaging the housing element  102  at generally the first end  104  and substantially encapsulating the forward portion  118  of the needle element  116  when the needle hub assembly  112  is in the injection position (as shown, for example, in  FIGS. 1 ,  2  and  26 ). Referring to  FIGS. 3 and 9  for illustration, the safety cap  144  may be adapted to removably engage a neck portion  160  of the housing element at generally the first end and substantially encapsulating the forward portion when the needle hub assembly is in the injection position. 
         [0051]    Referring now to  FIG. 10  for illustration, the syringe barrel  162  may have a lateral detent member  166  at generally the proximal end  164  for releasably engaging the first end  104  of the housing element  102  to secure the first end  104  from lateral movement outward of the breech opening  168  when the first end  104  is in releasable engagement with the lateral detent member  166 . In typical operation with a breech-loadable syringe assembly  156  having a lateral detent member  166  similar to that which is illustrated in  FIG. 10 , an embodiment of a safety carpule system  100  may be placed into the breech opening  168  beginning with the first end  104  of the housing element  102 . Once the first end  104  has entered the breech opening  168 , it is moved axially along the syringe barrel  162  toward the proximal end  164  and into engagement with the lateral detent member  166 . The safety carpule system  100  is then slightly rotated to place the plunger element  120  into releasable engagement with the syringe plunger rod  128 , thereby bringing the housing element  102  into substantial axial alignment with the syringe barrel  162 . The safety carpule system  100  is now loaded into the syringe for use in a dental or medical procedure. 
         [0052]    Once the safety carpule system  100  is loaded into a syringe, the safety cap  144  may be removed, and the liquid medication within the safety carpule system  100  may be injected into a patient by way of the forward portion  118  of the needle element  116 . Once the syringe plunger rod  128  has been axially compressed and the medication has been expended, the syringe plunger rod  128  can be returned to its uncompressed position, resulting in the needle hub assembly  112  being retracted completely into the housing element  102 . The plunger element  120  can then be disengaged from the syringe plunger rod  128 , and the safety carpule system  100  removed from the breech opening  168  for safe handling and disposal with or without replacement of the safety cap  144 . 
         [0053]    The foregoing detailed description of the invention is intended to be illustrative and is not intended to limit the scope of the invention. Changes and modifications are possible with respect to the embodiments detailed in the foregoing descriptions, and it is understood that the invention may be practiced otherwise than that specifically described herein and still be within the scope of the appended claims.