Abstract:
An injection device includes a barrel, a plunger having a portion structured and arranged to move within the barrel, a needle support, and a locking arrangement. The locking arrangement may at least one of selectively lock a proximal end portion of the plunger to the needle support and automatically lock a proximal end portion of the plunger to an outer portion of the needle support. This Abstract is not intended to define the invention disclosed in the specification, nor intended to limit the scope of the invention in any way.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates generally to syringes, e.g., hypodermic syringes, such are utilized for injection of medicament into the body tissues of human and animal patients. More specifically, this invention relates to a hypodermic syringe having a plunger, piston and needle support structure that permits retraction of the needle support and its needle into the barrel of the syringe to prevent the possibility of inadvertent needle pricks and which incorporates a frangible plunger that may be broken away to prevent subsequent actuation of the needle to its operative position. 
         [0003]    This invention also relates to syringes which have minimal dead-space so that they can be ideally used for injecting very expensive medicaments with minimal waste. 
         [0004]    This invention also relates to syringes which can be used only once, i.e., single-use syringes, and/or to syringes which utilize a rotating releasable lock system for locking the plunger to the needle support when desired. 
         [0005]    2. Discussion of Background Information 
         [0006]    In hospitals, nursing home facilities and the like, injection of medicament into the body tissues of patients is done on a daily basis. Typical hypodermic syringes are provided with a barrel having a needle that is fixed or removably attached at one end thereof. A plunger typically having an elastomeric piston is movable within the barrel to load the barrel with liquid medicament by suction as the plunger and piston are moved within the barrel in a direction away from the needle. After the needle has penetrated the body tissues of the patient, as the direction of movement of the plunger and piston are reversed and the piston is forced toward the needle, medicament contained within the barrel will be injected through the needle into the body tissues. 
         [0007]    After hypodermic syringes have been used in this manner, those syringes that are disposable present a significant problem to users, e.g., hospital or nursing home staff, because the possibility of inadvertent needle pricks subject personnel to the possibility of cross-contamination by, among other things, virile or bacterial contaminants that might be present on the needle after its use. In an effort to avoid the possibility of inadvertent needle pricks special waste containers are often provided at hospital facilities into which the used disposable hypodermic syringes are placed. These containers and the syringes contained therein are then disposed of in a specifically organized manner to insure against the possibility of inadvertent infectious contamination of nursing personnel. Further, refuse handlers and other persons who might inadvertently come into contact with the used hypodermic syringes are also subject to the same hazards. Often times the needles themselves are bent over so as to minimize the possibility of inadvertent needle pricks and to preclude the possibility of subsequent use of disposable hypodermic syringes. 
         [0008]    In certain situations, medicaments are injected into patients and not quickly thereafter discarded properly. Instead, the used syringe is placed in a temporary position. After the procedure has ended, the syringe can be manually recovered for disposal. However, between the time of use and the time of disposal, there is the possibility that inadvertent needle pricks will occur. Accordingly, it is desirable to provide a suitable way protecting personnel, e.g., nursing personnel, paramedics and other persons, from the hazards of inadvertent needle pricks as they go about their daily tasks. 
         [0009]    U.S. Pat. Nos. 5,328,475, 5,591,131, and 5,569,203 to CHEN, the disclosures of which are hereby expressly incorporated by reference in their entireties, discloses a hypodermic syringe which locks the plunger to the needle support when the plunger is moved to the full depth position during injection. During injection, however, the plunger irreversibly locks to the needle support when the plunger is moved to the full depth position. Furthermore, the plunger cannot be moved to the full depth position without causing engagement of the lock system. This means that there will be a dead space in the syringe if the plunger is not moved to the full depth position. This type of syringe is shown in  FIGS. 1-3  wherein the syringe barrel  1  has an internal cylindrical space for housing the medicine, a plunger  2  having an elastomer sealing piston is slidable engaged in the barrel  1  so as to cause the medicine to enter and exit the barrel  1 , and a needle support  3  is arranged in sealing engagement with a front end opening of the syringe. After the syringe is used for injecting a medicine, the plunger  2  is moved to the full injection position wherein it becomes automatically locked to the needle support  3 . Once the plunger  2  becomes locked to the needle support  3 , the plunger  2  can be used to fully retract the needle support  3  into barrel  1 . The rear end of the plunger  2  can then be snapped-off so as to prevent reuse of the syringe and ensure that the syringe cannot inadvertently prick the skin of anyone handling the syringe. 
         [0010]    U.S. Pat. No. 5,098,402 to DAVIS, the disclosure of which is hereby expressly incorporated by reference in its entirety, discloses a hypodermic syringe which locks the plunger to the needle support when the plunger is moved to the full depth position during injection. However, during injection, the plunger irreversibly locks to the needle support when the plunger is moved to the full depth position. Furthermore, the plunger cannot be moved to the full depth position without causing engagement of the lock system. This means that there will be a dead space in the syringe if the plunger is not moved to the full depth position. Moreover, the disclosed lock system prevents the plunger from rotating relative to needle support due to engagement between the plunger and the needle support. Finally, the plunger must be rotated to cause the needle support to rotate from a locked position to a position which allows the needle support to be retracted into the syringe barrel. 
         [0011]    U.S. Pat. No. 6,461,328 to WANG et al., the disclosure of which is hereby expressly incorporated by reference in its entirety, discloses a hypodermic syringe which locks the plunger to the needle support hub when the plunger is moved to the full depth position during injection. However, during injection, the plunger irreversibly locks to the needle support hub when the plunger is moved to the full depth position. Furthermore, the plunger cannot be moved to the full depth position without causing engagement of the lock system. This means that there will be a dead space in the syringe if the plunger is not moved to the full depth position. Moreover, the disclosed lock system prevents the plunger from rotating relative to needle support hub due to engagement between the plunger and the needle support hub. Finally, the plunger must be rotated to cause the needle support hub and the needle support secured thereto to rotate from a locked position to a position which allows the needle support hub and needle support to be retracted into the syringe barrel. 
         [0012]    it is therefore desirable to provide a syringe that includes a system for rendering the needle thereof to a protected, completely encapsulated condition such that it is less likely to cause, after use, an inadvertent needle prick during its handling or during its disposal. It is also desirable to provide a syringe having the capability of retracting the needle to a position inside the barrel of the syringe and locking the needle in its retracted position so that the needle of the syringe is always enclosed after its use, thus precluding the possibility that the needle might cause an accidental needle prick as the syringe is subsequently handled. It is also desirable to provide a syringe of the disposable type that is provided with facility for rendering it completely inoperative such that it can not be subsequently used. Additionally, it is desirable to provide for a syringe which also has minimal dead-space so that it can be ideally used for injecting very expensive medicaments with minimal waste. Finally, it is desirable to provide for a syringe which also has a system for selectively locking the plunger to the needle support so that the syringe can have minimal dead-space and so that the plunger and be locked with the needle support only when desired. 
       SUMMARY OF THE INVENTION 
       [0013]    According to one non-limiting aspect of the invention there is provided a hypodermic syringe having a plunger which can, in one orientation, be moved to the full depth position so as to allow essentially all of the contents of the syringe to be injected without causing the plunger to become locked with the needle support or the needle support hub and, in another orientation, a plunger can be moved to the full depth position so as to allow essentially all of the contents of the syringe to be injected while also causing the plunger to become locked with the needle support or the needle support hub. If the user desires, the plunger, while in the full depth position, can be rotated to cause unlocking of the plunger and needle support or can be rotated to cause locking of the plunger and needle support. 
         [0014]    According to one non-limiting aspect of the invention there is provided a prior art hypodermic syringe, e.g., of the type discussed above, that is modified to include one or more features of the invention described herein. By way of non-limiting example, the needle support or needle support hub can be press fit in a simple manner and with a simple design into the end opening of the syringe barrel and need not require the complex connection arrangements of the prior art discussed above. 
         [0015]    The invention also provides for a syringe whose needle support and/or needle support hub is capable of being easily and simply retracted to a safe position within the barrel where the needle is withdrawn to an enclosed and protected position preventing the possibility of inadvertent needle pricks. 
         [0016]    The invention also provides for a retractable hypodermic syringe having a frangible plunger that may be manually broken after the syringe has been used and the needle has been retracted and locked safely within the syringe barrel to thus render the syringe inoperative for further use. 
         [0017]    The invention also provides for a syringe including an internal selective locking system that utilizes a mechanical interaction between with a portion of the plunger to achieve locking of the needle support and/or needle support hub so as to allow the plunger to retract the needle support and/or needle support hub into the barrel of the syringe such that the needle is rendered incapable of causing an inadvertent needle prick. 
         [0018]    The invention is also directed to a retractable hypodermic syringe that includes one or more of the following features: a syringe body or cylindrical barrel. The barrel is designed to received therein a plunger. The proximal end of the plunger includes an elastomeric piston that sealingly engages with the internal cylindrical surface of the barrel. The distal end of the syringe body defines an opening which is sized and configured to receive therein a needle support. The needle support has a hypodermic needle affixed thereto, is press-fit (so as to be in sealingly engagement with) into the proximal opening of the barrel, and is also capable of being withdrawn into the barrel. The needle support is therefore capable of establishing a sealing engagement internally of the syringe body and defines a receptacle within which is received a connecting and actuating projection extending from the plunger such that a rotatable locking/unlocking relationship is established between the plunger and the needle support. Linear movement of the plunger in a direction away from the needle support is adapted to cause retracting movement of the needle support and needle to thus retract the needle to a protected position within the syringe barrel. The plunger and syringe barrel are also adapted for locking a portion of the plunger, the piston and needle support in a safe retracted position within the syringe barrel and for breaking away the operating portion of the plunger such that the syringe is rendered inoperative for further use. 
         [0019]    The invention also provides for an injection device comprising a barrel, a plunger having a portion structured and arranged to move within the barrel, a needle support, and a locking arrangement that one of selectively locks a proximal end portion of the plunger to the needle support and automatically locks a proximal end portion of the plunger to an outer portion of the needle support. 
         [0020]    The injection device may be at least one a syringe, a hypodermic syringe, a single-use syringe, and a retractable syringe. The barrel may comprise a cylindrically shaped internal space structured and arranged to receive therein a medicine. The barrel may further comprise a proximal opening within which the needle support is at least one of press fit and in sealing engagement therewith. The plunger may comprise a piston arranged at a proximal area of the plunger and an actuating flange arranged at a distal area of the plunger. The plunger may further comprise at least one of the piston being an elastomer or rubber piston, a frangible section adapted to allow the plunger to be broken in two, a stop flange adapted to limit forward movement of the plunger into the barrel, and a stop projection adapted to limit rearward movement of the plunger out of the barrel. The barrel, the plunger, and the needle support each comprise a synthetic resin material. The needle support may comprise a generally cylindrical distal portion and a needle projecting from a proximal end portion. The needle may comprise at least one of metal and stainless steel. The barrel may comprise at least one of a flange arranged at a distal end, a reduced diameter portion arranged at a proximal end, an internal taper arranged at a proximal end of the barrel adapted to facilitate insertion of the needle support, and at least one internal sealing projection arranged within a proximal end opening of the barrel adapted to sealingly engage an outer surface of the needle support. 
         [0021]    The locking arrangement may selectively lock a proximal end portion of the plunger to the needle support. The locking arrangement may selectively lock the proximal end portion of the plunger to the needle support upon rotation of the plunger. The locking arrangement may selectively lock the proximal end portion of the plunger to the needle support only upon rotation of the plunger. The locking arrangement may selectively lock the proximal end portion of the plunger to the needle support upon rotation of the plunger to a predetermined position. The locking arrangement may selectively lock the proximal end portion of the plunger to the needle support upon rotation of the plunger to a position approximately transverse to an initial unlocked position. The plunger may be movable to a full insertion or to a full injection position without causing the proximal end portion of the plunger to become locked to the needle support. The plunger may be movable to an injection position which minimizes a dead space without causing the proximal end portion of the plunger to become locked to the needle support. The plunger may be movable to an injection position which causes contact between a piston of the plunger and an internal shoulder of the barrel without causing the proximal end portion of the plunger to become locked to the needle support. The plunger may be movable to an injection position which causes contact between a portion of the plunger and an internal shoulder of the barrel without causing the proximal end portion of the plunger to become locked to the needle support. 
         [0022]    The proximal end portion of the plunger may comprise at least one of a generally flat projecting portion with oppositely arranged projections adapted to engage, in the locked position, with internal projecting shoulders of the needle support, a generally flat projecting portion with at least one projection adapted to engage, in the locked position, with at least one internal projecting shoulder of the needle support, a projecting portion comprising opposite facing planar surfaces and oppositely arranged projections adapted to engage, in the locked position, with internal projecting shoulders of the needle support, a projecting portion comprising opposite facing planar surfaces and at least one projection adapted to engage, in the locked position, with at least one internal projecting shoulder of the needle support, a projecting portion comprising at least one tapered projection adapted to engage, in the locked position, with at least one internal projecting shoulder of the needle support, a projecting portion comprising at least one fin-shaped projection adapted to engage, in the locked position, with at least one internal projecting shoulder of the needle support, and a generally cylindrical projecting portion comprising at least one fin-shaped projection adapted to engage, in the locked position, with at least one internal projecting shoulder of the needle support. 
         [0023]    The locking arrangement may automatically lock a proximal end portion of the plunger to an outer portion of the needle support. The locking arrangement may automatically lock the proximal end portion of the plunger to the outer portion of the needle support when the plunger is moved to at least one of a full insertion position and a full injection position. 
         [0024]    A distal end portion of the needle support may comprise at least one of a generally cylindrical opening sized to receive therein the proximal end portion of the plunger and at least one internal projecting shoulder adapted to engage, in the locked position, with at least one projection of the proximal end portion, a generally cylindrical opening sized to receive therein the proximal end portion of the plunger and two oppositely arranged internal projecting shoulders adapted to engage, in the locked position, with at least one projection of the proximal end portion, a generally cylindrical opening sized to receive therein the proximal end portion of the plunger and a generally rectangular-shaped distal entrance opening, and a generally cylindrical opening sized to receive therein the proximal end portion of the plunger and a generally double D-shaped distal entrance opening. 
         [0025]    The invention also provides for a syringe comprising a barrel, a plunger having a portion structured and arranged to move within the barrel, a needle support, and a locking arrangement that one of locks a proximal end portion of the plunger to the needle support when the plunger is rotated from an unlocked position to a locked position and locks the proximal end portion of the plunger to an outer portion of the needle support. 
         [0026]    The invention also provides for a syringe comprising a barrel comprising a main internal chamber for housing a medicine, a plunger having a piston structured and arranged to move within the main internal chamber and thumb engaging flange arranged outside the barrel, a needle support, and a locking arrangement that is structured and arranged to one of lock a proximal end portion of the plunger to the needle support when the plunger is rotated from a first position to a second position while being in a full injection position and lock a proximal end portion of the plunger to an outer portion of the needle support after being moved to a full injection position, wherein, when the plunger is in the full injection position, the syringe has essentially no dead space between the piston and an internal shoulder of the barrel. 
         [0027]    The invention also provides for a method of using any of the injection devices described above, wherein the method comprises moving the plunger away from the needle support so as to cause a desired amount of medicine to enter into the barrel, moving the plunger towards the needle support so as to cause medicine to exit the barrel through the needle support, and locking the proximal end portion of the plunger to the needle support by rotating the plunger from a first position to a second position. 
         [0028]    The method may further comprise, after the locking, moving the plunger away from the needle support so as to cause the needle support to be fully positioned within the barrel. 
         [0029]    The invention also provides for a method of using any of the injection devices described above, wherein the method comprises moving the plunger away from the needle support so as to cause a desired amount of medicine to enter into the barrel, moving the plunger towards the needle support so as to cause medicine to exit the barrel through the needle support and so as to position the plunger at least one of at a full injection position and at a position substantially eliminating a dead space in the syringe, again moving the plunger away from the needle support, and locking the proximal end portion of the plunger to the needle support by rotating the plunger from a first position to a second position. 
         [0030]    The method may further comprise, after the locking, moving the plunger away from the needle support so as to cause the needle support to be fully positioned within the barrel. 
         [0031]    The invention also provides for a method of using any of the injection devices described above, wherein the method comprises moving the plunger away from the needle support so as to cause a desired amount of medicine to enter into the barrel, moving the plunger towards the needle support so as to cause medicine to exit the barrel through the needle support, and locking the proximal end portion of the plunger to an outer portion of the needle support after the plunger is moved to a full injection position. 
         [0032]    The method may further comprise, after the locking, moving the plunger away from the needle support so as to cause the needle support to be fully positioned within the barrel. 
         [0033]    The invention also provides for a method of using any of the injection devices described above, wherein the method comprises moving the plunger away from the needle support so as to cause a desired amount of medicine to enter into the barrel, moving the plunger towards the needle support so as to cause medicine to exit the barrel through the needle support and so as to position the plunger at least one of at a full injection position and at a position substantially eliminating a dead space in the syringe, again moving the plunger away from the needle support, and locking the proximal end portion of the plunger to an outer portion of the needle support after the plunger is moved to a full injection position. 
         [0034]    The method may further comprise, after the locking, moving the plunger away from the needle support so as to cause the needle support to be fully positioned within the barrel. 
         [0035]    Other exemplary embodiments and advantages of the present invention may be ascertained by reviewing the present disclosure and the accompanying drawing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0036]    The present invention is further described in the detailed description which follows, in reference to the noted plurality of drawings by way of non-limiting examples of exemplary embodiments of the present invention, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein: 
           [0037]      FIG. 1  shows a cross-section view of a prior art syringe. The syringe is shown in a prior-use or packaged position and is ready to receive therein a medicine; 
           [0038]      FIG. 2  shows a cross-section view of the prior art syringe of  FIG. 1 . The syringe is shown moving to filling position. This would occur when the needle is inserted into a medicine bottle and the user begins to move the plunger back in order to place the desired amount of medicine into the syringe; 
           [0039]      FIG. 3  shows a cross-section view of the prior art syringe of  FIG. 2  after the syringe has assumed the used position. This would occur when the needle is inserted into tissue and the user moves move the plunger forwards in order to inject the medicine into the patient. As is evident from  FIG. 3 , movement of the plunger to the full injection position causes a front end portion of the plunger to become locked the needle support. The user need only move the plunger backwards to cause the needle support to retract into the syringe barrel so as to become fully housed therein; 
           [0040]      FIG. 4  shows a cross-section view of a syringe according to one embodiment of the invention. The syringe is shown in a prior-use or packaged position and is ready to receive therein a medicine; 
           [0041]      FIG. 5  shows a cross-section view of the syringe of  FIG. 4 . The syringe is shown after the plunger has moved to a desired filling position. This would occur when the needle is inserted into a medicine bottle and the user begins to move the plunger back in order to place the desired amount of medicine into the syringe; 
           [0042]      FIG. 6  shows a cross-section view of the syringe of  FIG. 4  after the syringe has assumed the used position. This would occur when the needle is inserted into tissue and the user moves the plunger forwards in order to inject the medicine into the patient. As is evident from  FIG. 6 , movement of the plunger to the full injection position causes a front end portion of the plunger to be inserted into the needle support by substantially the same amount as was the case in  FIG. 4 . No locking between the plunger and the needle support has occurred. In the position shown in  FIG. 6 , the user can move the plunger backwards without causing the needle support to retract into the syringe barrel; 
           [0043]      FIG. 7  shows a cross-section view of the syringe of  FIG. 6  after the syringe has assumed the locked position. This would occur when the user rotates the plunger (i.e., by about 90 degrees) from the position shown in  FIG. 6  to the position shown in  FIG. 7 . As is evident from  FIG. 7 , rotation of the plunger causes the projection shoulders of the front end portion of the plunger to be aligned with inwardly projecting shoulders of the needle support. The plunger and the needle support are now locked together. In the position shown in  FIG. 7 , the user can move the plunger backwards thereby causing the needle support to retract into the syringe barrel; 
           [0044]      FIG. 8  shows a cross-section view of the syringe of  FIG. 7  from another perspective that is 90 degrees to the perspective shown in  FIG. 7 . As is evident from  FIG. 8 , the projection shoulders of the front end portion of the plunger are aligned with inwardly projecting shoulders of the needle support. The plunger and the needle support are locked together; 
           [0045]      FIG. 9  shows a cross-section view of the syringe of  FIG. 8  after the plunger has been moved to a fully retracted position thereby placing the needle support within the syringe barrel; 
           [0046]      FIG. 10  shows a cross-section view of the syringe of  FIG. 9  after the plunger has been deflected to the point where it breaks leaving the portion with the piston and locked to the needle support within the syringe barrel; 
           [0047]      FIG. 11  shows a cross-section view of the syringe barrel used in the syringe shown in  FIG. 4 ; 
           [0048]      FIG. 12  shows a rear view of the syringe barrel shown in  FIG. 11 ; 
           [0049]      FIG. 13  shows a front view of the syringe barrel shown in  FIG. 11 ; 
           [0050]      FIG. 14  shows an enlarged cross-section view of the needle support used in the syringe of  FIG. 4 ; 
           [0051]      FIG. 15  shows a partial cross-section view of the needle support shown in  FIG. 14 ; 
           [0052]      FIG. 16  shows a rear view of the needle support shown in  FIG. 15 ; 
           [0053]      FIG. 17  shows a cross-section view of the syringe barrel and the needle support used in the syringe shown in  FIG. 4 . The needle support is shown in a position prior to being inserted into the front end opening of the syringe barrel; 
           [0054]      FIG. 18  shows a side view of the plunger used in the syringe shown in  FIG. 4 ; 
           [0055]      FIG. 19  shows a top view (a view transverse to the view shown in  FIG. 18 ) of the plunger shown in  FIG. 18 ; 
           [0056]      FIG. 20  shows a side view of the plunger and the needle support used in the syringe shown in  FIG. 4 . The plunger and needle support are shown in a locked position; 
           [0057]      FIG. 21  shows another side view of the plunger and the needle support used in the syringe shown in  FIG. 4 . The plunger and needle support are shown in a unlocked position; 
           [0058]      FIG. 22  shows an enlarged view of the plunger and the needle support shown in n  FIG. 21 , except that the plunger is rotated 90 degrees so as to show a transverse view of the unlocked position; 
           [0059]      FIG. 23  shows another view of  FIG. 22 , except that the plunger is positioned in the full injection position so as to eliminate the syringe barrel dead space; 
           [0060]      FIG. 24  shows a cross-section view of a syringe according to another embodiment of the invention. The syringe is shown in a locked position. The syringe can assume this position after injection and after the plunger is rotated to the locked position; 
           [0061]      FIG. 25  shows a rear view of the syringe shown in  FIG. 24  (from the perspective of the plunger thumb actuating flange being removed); 
           [0062]      FIG. 26  shows a cross-section view of a syringe according to another embodiment of the invention. The syringe is shown in an unlocked position. The syringe can have this position both before use, after injection, and before the plunger is rotated to the locked position; 
           [0063]      FIG. 27  shows a rear view of the syringe shown in  FIG. 26  (from the perspective of the plunger thumb actuating flange being removed); 
           [0064]      FIG. 28  shows an enlarged cross-section view of a syringe according to another embodiment of the invention. The syringe is shown in an unlocked position. The syringe can assume this position prior to use; 
           [0065]      FIG. 29  shows another enlarged cross-section view of  FIG. 28  and illustrates an intermediate position as the plunger moves towards the locked position. The syringe can assume this position during or after injection; 
           [0066]      FIG. 30  shows another enlarged cross-section view of  FIG. 28  and illustrates a locked position of the plunger and needle support. The syringe can assume this position after injection; 
           [0067]      FIG. 31  shows another enlarged cross-section view of  FIG. 28  and illustrates how the plunger can cause the needle support (which is locked thereto) to be retracted into the syringe barrel; 
           [0068]      FIG. 32  shows an enlarged cross-section view of a syringe according to still another embodiment of the invention. The syringe is shown in an unlocked position. The syringe can assume this position prior to use; 
           [0069]      FIG. 33  shows another enlarged cross-section view of  FIG. 32  and illustrates a locked position of the plunger and needle support. The syringe can assume this position after injection; 
           [0070]      FIG. 34  shows an enlarged cross-section view of a syringe according to still another embodiment of the invention. The syringe is shown in an unlocked position. The syringe can assume this position prior to use; 
           [0071]      FIG. 35  shows a rear view of the needle support which can be used in the syringe shown in  FIG. 34 ; 
           [0072]      FIG. 36  shows a rear view of the needle support shown in  FIG. 35  and illustrates a cross-section of the front end of the plunger. This figure illustrates how the front end of the plunger is inserted in the needle support and shows a rear view of the unlocked position; 
           [0073]      FIG. 37  shows an enlarged cross-section view of a syringe according to still another embodiment of the invention. The syringe is shown in an unlocked position. The syringe can assume this position prior to use; 
           [0074]      FIG. 38  shows a rear view of the needle support which can be used in the syringe shown in  FIG. 37 ; and 
           [0075]      FIG. 39  shows a rear view of the needle support shown in  FIG. 38  and illustrates a cross-section of the front end of the plunger. This figure illustrates how the front end of the plunger is inserted in the needle support and shows a rear view of the unlocked position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0076]    Referring now to the drawings and first to  FIG. 4  which shows a first embodiment of a retractable hypodermic syringe. The syringe includes a generally elongate cylindrical barrel  10  having a transverse flange  11  arranged at a distal end of the barrel  10 . The proximal end of the barrel  10  includes a reduced diameter section  12  which forms a tubular extension and/or a cylindrical sleeve which is disposed concentrically about a proximal end passage  13  (see  FIG. 11 ) that extends through the section  12  and into a main internal chamber  14  defined by the main cylindrical section of the barrel  10 . 
         [0077]    A needle support  30  is normally positioned within the passage  13  (see  FIG. 11 ) and includes a rear end portion  31  (see  FIG. 14 ) which is sealed to and/or in frictional engagement with the cylindrical section  12 . As shown in  FIG. 1 , the rear end portion  31  of the needle support  30  includes a main opening  32  configured to receive therein a front or proximal end portion  24  of the plunger  20 . 
         [0078]    Arranged within the barrel  10  of the syringe is movably disposed a plunger  20 . The plunger  20  can, by way of non-limiting example, be formed by intersecting webs of polymer material which may be molded in integral assembly to provide a light-weight plunger having sufficient structural integrity for loading the barrel  10  with medicament and dispensing the medicament through the passage  14  and hollow needle  36  into the body tissues of the patient. The plunger  20  is also of sufficient structural integrity for imparting rotational movement to the needle support  30  as will be described below for the purpose of locking and unlocking the plunger to the needle support  30  relative to the barrel  10 . The plunger  20  is provided with an end flange  26  which is typically engaged by the thumb of the user while the transverse flange  11  is engaged by the fingers of the user in order to enable the plunger  20  to be forced into the barrel  10  for the purpose of expelling the medicament from the barrel  10  through the passage  14 . The plunger  20  also utilizes weakened portions of the webs to form a frangible section  25  (see  FIGS. 18 and 19 ) which enables the distal section  21  of the plunger  20  to be broken away from the proximal section  22  in the manner shown in  FIG. 10 . The frangible section  25  may also be scored to insure that it will break at the proper location. The section  25 , of course, should be of appropriate dimension in order to provide sufficient structural integrity to the plunger  20  to enable the plunger  20  to transmit locking and unlocking forces to the needle support  30  and to impart linear force to the plunger  20 . 
         [0079]      FIG. 4  shows the syringe in a prior-use or packaged position and is ready to receive therein a medicine and illustrates how the portion  24  is inserted within the opening  32  of the needle support  30  without causing the plunger  20  to become locked to the needle support  30 . 
         [0080]      FIG. 5  shows the syringe of  FIG. 4  after the plunger  20  has moved (i.e., been retracted) to a desired filling position. This would occur when, e.g., the needle  36  is inserted into a medicine bottle and the user begins to move the plunger  20  rearward or back in order to place the desired amount of medicine into the syringe. 
         [0081]      FIG. 6  shows the syringe of  FIG. 4  after the syringe has assumed the used or injection position. This would occur when the needle  36  is inserted into tissue and the user moves the plunger  20  forwards in order to inject the medicine into the patient. As is evident from  FIG. 6 , movement of the plunger  20  to the substantially full injection position causes the front end or proximal end portion  24  of the plunger  20  to be inserted into the needle support  30  by substantially the same amount as was the case in  FIG. 4 . Furthermore, no automatic locking has occurred between the plunger  20  and the needle support  30 . In the position shown in  FIG. 6 , the user can move the plunger  20  backwards without causing the needle support  30  to become unlocked to and/or un-engaged with the section  12  and retract into the syringe barrel  10 . The full injection position of the syringe can be defined by contact between plunger flange  27  and the barrel flange  11  and/or by contact between the leading edge of the plunger piston  23  and the bottom shoulder  15  of the barrel  10 . In the latter case, the dead-space of the syringe is effectively and/or substantially eliminated or minimized. 
         [0082]      FIG. 7  shows the syringe of  FIG. 6  after the syringe has assumed the locked position. This would occur when the user rotates the distal flange  26  of the plunger  20  (e.g., by about 90 degrees) from the position shown in  FIG. 6  to the position shown in  FIG. 7 . Of course, the invention is not limited to rotational movements which are 90 degrees and can be any desired rotational angle. To ensure that the user can easily perform this rotation movement relative to the barrel  10 , the outer circumferential surface of the flange  26  can be provided with a high friction surface (not shown) which take the form of e.g., a knurl, a textured surface, a high friction coating made of e.g., rubber or silicone. The invention also contemplates making some portion of all of the outer cylindrical circumferential surface of the barrel  10  or the flange  11  with a similar high friction surface (not shown). As is evident from  FIG. 7 , rotation of the plunger  20  causes the projection shoulders  24   a  and  24   b  (see  FIG. 18 ) of the front end portion  24  of the plunger  20  to become aligned with inwardly projecting shoulders  34   a  and  34   b  (see  FIG. 14 ) of the needle support  30 . The plunger  20  and the needle support  30  are now locked together. That is, in this position, movement of the plunger  20  rearward will cause engagement between the projection shoulders  24   a  and  24   b  and the inwardly projecting shoulders  34   a  and  34   b  thereby ensuring that axial movement of the plunger  20  will translate to corresponding axial movement of the needle support  30 . In the position shown in  FIG. 7 , the user can, ant any desired time, move the plunger  20  backwards thereby causing the needle support  30  to retract into the syringe barrel  10 . 
         [0083]      FIG. 8  shows the syringe of  FIG. 7  from a perspective that is 90 degrees to the perspective shown in  FIG. 7 . As is evident from  FIG. 8 , the projection shoulders  24   a  and  24   b  of the front end portion  24  of the plunger  20  are aligned with inwardly projecting shoulders  34   a  and  34   b  of the needle support  30 . The plunger  20  and the needle support  30  are, as explained above, locked together. 
         [0084]      FIG. 9  shows the syringe of  FIG. 8  after the plunger  20  has been moved to a fully retracted position, i.e., defined by engagement with or contact between circular projection or flange  28  (see  FIG. 18 ) and internal circular projection  16  (see  FIG. 11 ), thereby positioning the needle support  30  fully within the syringe barrel  10 . In this position, it is nearly impossible for anyone coming in contact with the syringe to get pricked by the needle  36 . 
         [0085]      FIG. 10  shows the syringe of  FIG. 9  after the plunger  10  has been deflected to the point where it breaks leaving the proximal portion  22  with the piston locked to the needle support  30  within the syringe barrel  10 . The breaking of the plunger  20  occurs, of course, at the frangible section  25 . As is evident from  FIG. 10 , once the distal section  21  is removed, the syringe is rendered entirely unusable and can be safely disposed of and/or handled without concern that anyone handling the syringe will be pricked by the needle  36  by accident. 
         [0086]      FIG. 11  shows the syringe barrel  10  used in the syringe shown in  FIG. 4 . The syringe barrel  10  is a generally elongate cylindrical barrel having a flange  11  arranged at a distal end of the barrel  10 . As is shown in  FIGS. 12 and 13 , the flange  11  can a polygonal shape. Of course, the invention also contemplates other shapes such as, e.g., circular, oval, as well as other polygonal shapes. The proximal end of the barrel  10  includes a reduced diameter section  12  which forms a tubular extension and/or a cylindrical sleeve. The section  12  is disposed concentrically about a generally cylindrical proximal end passage  13  that extends through the section  12  into a main internal chamber  14  defined by the main cylindrical section of the barrel  10 . The proximal end of the barrel  10  includes an internal tapered section  12   a  which facilitates insertion of the needle support  30  from the proximal end. In order to prevent any medicine from leaking out of the syringe and to ensure that the needle support  30  is axially constrained so that the syringe can be used without the needle support  30  moving prematurely, the section  12  includes at least one and preferably two or more circular spaced-apart projections  12   b  and  12   c  which are configured to frictionally and/or sealingly engage with the outer cylindrical surface of the needle support  30 . The invention, however, contemplates other mechanisms for ensuring that the syringe can be used without the needle support  30  moving prematurely. For example, it is contemplated that the needle holder  30  can instead be provided with one or more circular projections which frictionally engage a generally cylindrical inner surface of the section  12 . The barrel  10  also includes a bottom shoulder  15  which when contacted by the leading end of the piston  23  ensures that the syringe has substantially no dead space. This can be particularly important when the medicine is very expensive and/or rare and one seeks to minimize any waste thereof. This can also be particularly important when the medicine must be administered in very precise dosages. The barrel  10  also includes a circular projection  16  which serves to prevent the plunger  20  from being move rearwardly beyond a desired point. The projection  16  also serves to locate the frangible section  25  is a predetermined position outside of the barrel  10  to ensure that the distal section  21  will break with the least amount of effort. 
         [0087]      FIGS. 14-16  show the needle support  30  which is used in the embodiment shown in  FIG. 4 . The needle support  30  includes a distal section  31  which is sized and configured to be press-fit inside the passage  13 . As was explained above, the rear end portion  31  is preferably sealed to and/or in frictional engagement with the cylindrical section  12  so as to ensure that the syringe does not leak and so that the needle support  30  is prevented from axial movement until being so moved by the plunger  20 . The rear end portion  31  of the needle support  30  includes a main opening  32  configured to receive therein a front or proximal end portion  24  of the plunger  20 . However, in order for the portion  24  to enter into the opening  32 , the needle holder  30  also includes a key or entrance opening  33  which is defined by one or more internally projecting shoulders  34   a  and  34   b . This opening  33  prevents the portion  24  from locking with the needle holder  30  unless the portion is oriented or rotated to a correct position. The needle support  30  also includes a proximal hollow needle  36  which extends from a smaller diameter section  35  arranged between the needle  36  and the section  31 . As is apparent from  FIG. 14 , the needle  36  extends all the way through section  35  and provides a fluid passage communicating with opening  32 . Section  35  can have any desired configuration or size and serves mainly as the portion of the needle support  30  or syringe to which a needle protection cap (not shown) is mounted. As can be seen in  FIG. 16 , the entrance opening  33  can have the form of a “double D” shaped opening. 
         [0088]      FIG. 17  shows the syringe barrel  10  and the needle support  30  used in the syringe shown in  FIG. 4 . The needle support  30  is shown in a position prior to being inserted into the front end opening  13  of the syringe barrel  10 . The needle support  30  is preferably press-fit into the opening  13  and this insertion is facilitated by the tapered section  12   a.    
         [0089]      FIGS. 18-19  show the plunger  20  that is used in the syringe shown in  FIG. 4 . As explained above, the plunger  20  can be formed by intersecting webs of polymer material which may be molded in integral assembly to provide a light-weight plunger having sufficient structural integrity for loading the barrel with medicament and dispensing the medicament through the passage  14  and the hollow needle  36  into the body tissues of the patient. The plunger  20  is also of sufficient structural integrity for imparting rotational movement to the needle support  30  as was explained above for the purpose of locking and unlocking the needle support  30  and cause its movement relative to the barrel  10 . The plunger  20  is provided with an end flange  26  which is typically engaged by the thumb of the user in order to enable the plunger  20  to be forced into the barrel  10  for the purpose of expelling the medicament from the barrel  10  through the passage  13 . Intermediate the extremities of the plunger  20  is a frangible section  25  that allows the distal end  21  of the plunger  20  to be broken off in the manner shown in  FIG. 10 . The frangible section  25  may also be scored to insure that it will break at the proper location. Of course, the section  25  should also be of appropriate dimension to provide sufficient structural integrity to the plunger  20  and enable the locking and unlocking forces to be imparted to the needle support  30  and also to impart linear force to the plunger piston  23 . 
         [0090]    At a forward or proximal end of the plunger  20  there is provided a transverse support or abutment flange  29  which is of a dimension less than that of the internal cylindrical surface of the barrel  10 . The flange  29  provides abutting support for a resilient piston  23  which is mounted to piston support portion that is integral with the plunger  20  and extends forwardly of the piston abutment flange  29 . The piston support portion (not shown) can also include an intermediate enlargement which engages with an internal recess (not shown) of the piston  23  thus serving to secure the piston  23  to the plunger  20  thereby permitting relative rotation of the piston  23  and plunger  20 . The piston  23  also defines a pair of spaced opposite facing external sealing lands that establish sealing engagement with the internal cylindrical internal wall of the syringe barrel  10 . Thus, as the plunger  20  moves linearly and axially within the barrel  10  the piston lands maintain sealing engagement with the inner cylindrical surface and thereby provide the plunger  20  with the capability of imparting significant hydraulic pressure to the liquid medicament which may be contained within the syringe barrel  10 . Of course, the invention contemplates other plunger and piston configurations whether conventional or otherwise. 
         [0091]    Since, in the embodiment shown in  FIG. 4 , it is desirable to provide a releasable connection between the plunger  20  and the needle support  30 , the plunger  20  includes a proximal end portion  24  which functions as a key and allows the plunger  20  to be selectively locked to the needle support  30 . In this regard, the proximal end portion  24  has a tapered leading end, one or more tapered projections  24   a  and  24   b  which can selectively engage with one or more projections  34   a  and  34   b  of the needle support  30  depending on the rotational position of the plunger  20 . In the non-limiting embodiment shown in  FIGS. 18 and 19 , the portion  24  is a generally flat member having opposite facing generally planar sides  24   c  and  24   d . The thickness between the sides  24   c  and  24   d  can any desired value provide that the portion  24  maintains sufficient strength to function as intended. Preferably the thickness is between approximately 25% and 75% of the overall width of portion  24  as measured in  FIG. 18 . 
         [0092]      FIG. 20  shows the plunger  20  and the needle support  30  used in the syringe shown in  FIG. 4 . The plunger  20  and the needle support  30  are shown in a locked position. This can occur when the plunger  20  is rotated approximately 90 degrees from the position in  FIG. 21 . 
         [0093]      FIG. 21  shows the plunger  20  and the needle support  30  used in the syringe shown in  FIG. 4 . The plunger  20  and the needle support  30  are shown in a unlocked position. This can occur when the plunger  20  is rotated approximately 90 degrees from the position in  FIG. 20 . 
         [0094]      FIG. 22  shows an enlarged view of the plunger  20  and the needle support  30  shown in n  FIG. 21 , except that the plunger  20  is rotated 90 degrees so as to show a transverse view of the unlocked position.  FIG. 23  shows another view of  FIG. 22 , except that the plunger  20  is positioned in the full injection position so as to eliminate the syringe barrel dead space, i.e., the leading end of the piston  23  can come into contact with shoulder  15 . 
         [0095]      FIGS. 24-27  shows a syringe according to another embodiment of the invention. The syringe is similar to the embodiment shown in  FIG. 4 , except that the syringe utilizes a system for setting the plunger  20 ′ in each of the locked and unlocked positions. As is shown in  FIGS. 25 and 27 , the system utilizes a cut-away section of the flange  27 ′ resulting in the flange  27 ′ having two stop surfaces. When the plunger  20 ′ is rotated to the position shown in  FIG. 25 , one stop surface of the flange  27 ′ contacts a stop projection  17  integrally formed on the flange  11 ′ of the barrel  10 ′. When the plunger  20 ′ is rotated to the position shown in  FIG. 27 , another stop surface of the flange  27 ′ contacts the stop projection  17  integrally formed on the flange  11 ′ of the barrel  10 ′. In order to provide the user with a visual indication of the locked and unlocked positions, the flange  27 ′ can include symbols. For example, the symbol “L” can be used to designate when the plunger  20 ′ is locked to the needle support  30  and the symbol “U” can be used to designate when the plunger  20 ′ is unlocked to the needle support  30 . 
         [0096]      FIGS. 28-31  show a syringe according to another embodiment of the invention. In  FIG. 28 , the syringe is shown in an unlocked position. The syringe can assume this position prior to use. In this embodiment, the proximal end portion  24 ″ of the plunger is a generally cylindrically shaped member with a tapered free end to allow for easy insertion into the opening  32 ′ of the needle support  30 ′. Furthermore, the portion  24 ″ utilizes a circumferential tapered projection  24 ″ a  which, when the plunger is in the locked position (i.e., the full injection position), is configured to engage with a circumferential inwardly projecting rib  34 ′ a . However, as long as the plunger does not assume the substantially fully injection position (see  FIG. 30 ), the portion  24 ″ will not become locked to the needle support  30 ′. In order to lock the plunger to the needle support  30 ′, the embodiment shown in  FIGS. 28-31  utilizes a sleeve-shaped plunger locking member which includes an inwardly facing circular locking projection LP is configured to lock with a circular locking recess LR arranged on an exterior surface of the needle support  30 ′. In order to ensure that the medicine is not prevented from exiting the syringe when the plunger is nearing the full injection position, the sleeve-shaped plunger locking member includes a plurality of through openings OP. These openings OP can be equally spaced and can be any number between, e.g., 1 and 12. Alternatively or in addition to the openings OP, the sleeve-shaped plunger locking member can include slots so as to form a plurality of spaced apart fingers each having a portion of the locking projection LP. As is evident from  FIGS. 28-31 , the plunger becomes locked to the needle support  30 ′ when the locking projection LP is received in the locking recess LR.  FIG. 29  illustrates an intermediate position as the plunger moves towards the locked position. The syringe can assume this position during or after injection.  FIG. 30  illustrates a locked position of the plunger and needle support  30 ′. As is evident from  FIG. 30 , the distal end of the needle support  30 ′ is forced to deflect inwardly as the sleeve-shaped plunger locking member moves over the distal end. Although not shown, the distal end of the needle support  30 ′ in the area of the locking recess LR can include slots so as to form a plurality of spaced apart fingers each having a portion of the locking recess LR. This would more easily allow the distal end to deflect inwardly and facilitate locking.  FIG. 30  illustrates that when the plunger is locked to the needle support  30 ′, the syringe has substantially no dead space.  FIG. 31  illustrates how the plunger can cause the needle support  30 ′ (which is locked in a permanent or non-releasable manner thereto) to be retracted into the syringe barrel. 
         [0097]      FIGS. 32-33  show a syringe according to another embodiment of the invention. In  FIG. 32 , the syringe is shown in an unlocked position. The syringe can assume this position prior to use. In this embodiment, the proximal end portion  24 ′″ of the plunger is a generally cylindrically shaped member with a tapered free end to allow for easy insertion into the opening  32 ′ of the needle support  30 ′. Furthermore, the portion  24 ′″ utilizes a distal shoulder  24 ″ a  which, when the plunger is in the locked position (i.e., the full injection position), is configured to engage with a circumferential inwardly projecting rib  34 ′ a . However, as long as the plunger does not assume the substantially fully injection position (see  FIG. 33 ), the portion  24 ′″ will not become locked to the needle support  30 ′. In order to lock the plunger to the needle support  30 ′, the embodiment shown in  FIGS. 32-33  utilizes a sleeve-shaped plunger locking member which includes an inwardly facing circular locking projection LP is configured to lock with a circular locking recess LR arranged on an exterior surface of the needle support  30 ′. In order to ensure that the medicine is not prevented from exiting the syringe when the plunger is nearing the full injection position, the sleeve-shaped plunger locking member includes a plurality of through openings OP. These openings OP can be equally spaced and can be any number between, e.g., 1 and 12. Alternatively or in addition to the openings OP, the sleeve-shaped plunger locking member can include slots so as to form a plurality of spaced apart fingers each having a portion of the locking projection LP. As is evident from  FIGS. 32 and 33 , the plunger becomes locked to the needle support  30 ′ when the locking projection LP is received in the locking recess LR.  FIG. 32  illustrates an intermediate position as the plunger moves towards the locked position. The syringe can assume this position during or after injection.  FIG. 33  illustrates a locked position of the plunger and needle support  30 ′. As is evident from  FIG. 33 , the distal end of the needle support  30 ′ is forced to deflect inwardly as the sleeve-shaped plunger locking member moves over the distal end. Although not shown, the distal end of the needle support  30 ′ in the area of the locking recess LR can include slots so as to form a plurality of spaced apart fingers each having a portion of the locking recess LR. This would more easily allow the distal end to deflect inwardly and facilitate locking.  FIG. 33  illustrates that when the plunger is locked to the needle support  30 ′, the syringe has substantially no dead space. Furthermore, because the proximal portion  24 ′″ is sized to substantially fill the space  32 ′ of the needle support  30 ′, the dead space within the space  32 ′ is substantially reduced. Although not shown, the plunger can cause the needle support  30 ′ (which is locked in a permanent or non-releasable manner thereto) to be retracted into the syringe barrel in the same manner as shown in  FIG. 31 . 
         [0098]      FIGS. 34-36  show a syringe according to another embodiment of the invention. In  FIG. 34 , the syringe is shown in an unlocked position. The syringe can assume this position prior to use and after use. In this embodiment, the proximal end portion  24   IV  of the plunger is a generally cylindrically shaped member with a tapered free end to allow for easy insertion into the opening  32 ″ of the needle support  30 ″. Furthermore, the portion  24   IV  utilizes a tapered projection  24   IV ′a which, when the plunger is in the locked position (i.e., the plunger is moved to the full injection position and rotated by an angle in either direction that is sufficient to move the projection  24   IV   a  out of alignment with the slot SL formed in the needle support  30 ″), is configured to engage with a circumferential inwardly projecting rib  34 ″ a . However, as long as the plunger is not rotated while in the substantially fully injection position (see  FIG. 34 ), the portion  24   IV  will not become locked to the needle support  30 ″. In order to lock the plunger to the needle support  30 ″, the embodiment shown in  FIGS. 34-36  utilizes a tapered projection  24   IV   a  which is configured to lock with the circumferential inwardly projecting rib  34 ″ a . As is evident from  FIGS. 34-36 , the plunger becomes locked to the needle support  30 ″ when the portion  24   IV  is received in the space  32 ″ (after passing through opening  33 ″) and then rotated from the position shown in  FIG. 36  to an angular position which positions the projection  24   IV   a out of alignment (not shown) with the keying slot SL of the needle support  30 ″. The angle can be, e.g., as little as about 5 degrees or more, and in the embodiment shown in  FIGS. 34-36  can be any value between about 5 degrees and about 355 degrees. Of course, this embodiment can also be modified to utilize two or more tapered projections utilize  24   IV   a  instead of just one. 
         [0099]      FIGS. 37-39  show a syringe according to another embodiment of the invention. In  FIG. 37 , the syringe is shown in an unlocked position. The syringe can assume this position prior to use and after use. In this embodiment, the proximal end portion  24   V  of the plunger is a generally planar member (see  FIG. 39 ) with a tapered free end to allow for easy insertion into the opening  32 ′″ of the needle support  30 ′″. Furthermore, the portion  24   V  utilizes a tapered projection  24   V   a  which, when the plunger is in the locked position (i.e., the plunger is moved to the full injection position and rotated by an angle in either direction that is sufficient to move the projection  24   V   a  out of alignment with the slot SL formed in the needle support  30 ′″), is configured to engage with a circumferential inwardly projecting rib  34 ′″a. However, as long as the plunger is not rotated while in the substantially fully injection position (see  FIG. 39 ), the portion  24   V  will not become locked to the needle support  30 ″. In order to lock the plunger to the needle support  30 ′″, the embodiment shown in  FIGS. 37-39  utilizes a tapered projection  24   V   a  which is configured to lock with the circumferential inwardly projecting rib  34 ′″a. As is evident from  FIGS. 37-39 , the plunger becomes locked to the needle support  30 ′″ when the portion  24   V  is received in the space  32 ′″ (after passing through opening  33 ′″) and then rotated from the position shown in  FIG. 39  to an angular position which positions the projection  24   V   a  out of alignment (not shown) with the keying slot SL of the needle support  30 ′″. The angle can be, e.g., as little as about 5 degrees or more, and in the embodiment shown in  FIGS. 37-39  can be any value between about 5 degrees and about 355 degrees. Of course, this embodiment can also be modified to utilize two or more tapered projections utilize  24   V   a  instead of just one. 
         [0100]    The syringe described above can also utilize one or more features disclosed in the prior art documents expressly incorporated by reference herein. Furthermore, one or more of the various parts of the syringe can preferably be made as one-piece structures by e.g., injection molding, when doing so reduces costs of manufacture. Non-limiting materials for most of the parts include synthetic resins such as those approved for syringes or other medical devices. Furthermore, the invention also contemplates that any or all disclosed features of one embodiment may be used on other disclosed embodiments, to the extent such modifications function for their intended purpose. 
         [0101]    It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to an exemplary embodiment, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.