Patent Publication Number: US-11020528-B2

Title: Automatic injection device for administration of high viscosity medication

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of U.S. patent application Ser. No. 14/786,696 filed Oct. 23, 2015, which is a National Stage of International Application No. PCT/IL2014/050375 filed Apr. 23, 2014, claiming priority based on U.S. Provisional Patent Application No. 61/815,257, filed Apr. 23, 2013, the contents of all of which are incorporated herein by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to automatic injection devices and more particularly to automatic injection devices for administration of high viscosity medications. 
     BACKGROUND OF THE INVENTION 
     The delivery of a high viscosity medication using a syringe typically requires an automatic injector including a strong spring. One of the disadvantages in the usage of such an automatic injector having a strong spring is that it can result in the breakage of the syringe during the operation of the device. Additionally, dimensions of known automatic injection devices having strong springs are normally substantially larger than those of injectors without such springs. 
     SUMMARY OF THE INVENTION 
     The present invention seeks to provide an improved automatic injection device for high viscosity fluids. 
     There is thus provided in accordance with a preferred embodiment of the present invention an automatic injection device configured for injection of a material stored in a syringe into an injection site, the syringe including a generally cylindrical storage container and a piston disposed within the generally cylindrical storage container, whose exact initial axial position within the generally cylindrical storage container is not predetermined, wherein axial forward displacement of the piston in the generally cylindrical storage container forces the material forwardly out of the generally cylindrical storage container, the automatic injection device including at least one spring drive assembly operative, when actuated, to initially apply a first axial force to the syringe, thereby to axially displace the syringe in a forward direction, and thereafter, responsive to driving engagement with the piston, to apply a second axial force, substantially greater than the first axial force, notwithstanding the fact that the exact axial position of the piston within the generally cylindrical storage container is not predetermined, to the piston, thereby to axially displace the piston relative to the syringe in the forward direction. 
     There is also provided in accordance with another preferred embodiment of the present invention an automatic injection device configured for injection of a material stored in a syringe into an injection site, the syringe including a generally cylindrical storage container and a piston disposed within the generally cylindrical storage container, whose exact initial axial position within the generally cylindrical storage container is not predetermined, wherein axial forward displacement of the piston in the generally cylindrical storage container forces the material forwardly out of the generally cylindrical storage container, the automatic injection device including at least one spring drive assembly operative, when actuated, to initially apply a first axial force to a plunger to axially displace the plunger in a forward direction, and thereafter, responsive to engagement of the plunger with the piston, to apply a second axial force, substantially greater than the first axial force, notwithstanding the fact that the exact axial position of the piston within the generally cylindrical storage container is not predetermined, to the piston, thereby to axially displace the piston relative to the syringe in the forward direction. 
     The is further provided in accordance with yet another preferred embodiment of the present invention an automatic injection device configured for injection of a material stored in a syringe into an injection site, the syringe including a generally cylindrical storage container and a piston disposed within the generally cylindrical storage container, whose exact initial axial position within the generally cylindrical storage container is not predetermined, wherein axial forward displacement of the piston in the generally cylindrical storage container forces the material forwardly out of the generally cylindrical storage container, the automatic injection device including at least one spring drive assembly including at least one spring and at least one selectably operable spring energy output force limiter, the at least one selectably operable spring energy output force limiter being automatically disabled responsive to driving engagement of the at least one spring drive assembly with the piston. 
     Preferably, the plunger is spaced from the piston when the automatic injection device is in a storage orientation. Additionally or alternatively, the at least one spring drive assembly is configured to forwardly displace the plunger into engagement with the piston. 
     In accordance with a preferred embodiment of the present invention the at least one spring drive assembly includes at least one spring and at least one selectably operable spring energy output force limiter, the at least one selectably operable spring energy output force limiter being automatically disabled responsive to driving engagement of the at least one spring drive assembly with the piston, the at least one spring providing the first axial force when the at least one selectably operable spring energy output force limiter is not disabled, and providing the second axial force when the at least one selectably operable spring energy output force limiter is disabled. Additionally or alternatively, the at least one spring drive assembly stretches the at least one selectably operable spring energy output force limiter. Alternatively or additionally, the at least one selectably operable spring energy output force limiter absorbs a portion of the force of the at least one spring drive assembly. 
     In accordance with a preferred embodiment of the present invention the syringe includes a needle shield and the automatic injection device also includes a needle shield remover, the needle shield remover including an exterior needle shield remover and an interior needle shield remover, the exterior needle shield remover and the interior needle shield remover being configured to permit limited relative axial movement therebetween, thereby to compensate for manufacturing tolerance inaccuracies of the automatic injection device and the syringe. Additionally, the exterior needle shield remover and the interior needle shield remover are configured to be axially displaceable relative to each other at a first operative stage and not axially displaceable relative to each other at a second operative stage. 
     Preferably, the automatic injection device also includes a syringe sleeve and a relative movement restrictor operative to prevent relative movement of the syringe and the syringe sleeve when the automatic injection device is in a storage orientation. Preferably, the automatic injection device and the syringe sleeve are configured to allow visual examination of the contents of the syringe. 
     In accordance with a preferred embodiment of the present invention the automatic injection device also includes a trigger button and a trigger button locking assembly operative to prevent forward movement of the trigger button when the automatic injection device is in a storage orientation. 
     Preferably, the syringe also includes a needle and a needle shield configured to prevent exposure of the needle in a post-injection orientation. 
     In accordance with a preferred embodiment of the present invention the automatic injection device also includes a front housing, a needle shield and a trigger button, the automatic injection device being configured to be activatable by forwardly displacing the trigger button after rearwardly displacing the needle shield relative to the front housing. Additionally, the automatic injection device is configured such that forward displacement of the trigger button actuates the at least one spring drive assembly. 
     Preferably, the automatic injection device also includes a resilient ring positioned on the syringe. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: 
         FIG. 1  is a simplified pictorial exploded view illustration of an Automatic Injection Device for Administration of High Viscosity Medication (AIDAHVM) constructive and operative in accordance with a preferred embodiment of the present invention; 
         FIGS. 2A and 2B  are simplified rear facing pictorial view and side view illustrations of an exterior Rigid Needle Shield (RNS) remover forming part of the AIDAHVM of  FIG. 1 ; 
         FIGS. 2C and 2D  are simplified sectional view illustrations of the exterior RNS remover as shown in  FIGS. 2A and 2B , taken along lines IIC-IIC and IID-IID in  FIGS. 2A and 2C , respectively; 
         FIGS. 3A and 3B  are a simplified side view illustration and a simplified top view illustration of an interior Rigid Needle Shield (RNS) remover forming part of the AIDAHVM of  FIG. 1 ; 
         FIG. 3C  is a simplified sectional view illustration of the interior RNS remover as shown in  FIGS. 3A and 3B , taken along lines IIIC-IIIC in  FIG. 3B ; 
         FIG. 4A  is a simplified pictorial view illustration of a front housing forming part of the AIDAHVM of  FIG. 1 ; 
         FIGS. 4B and 4C  are a simplified side view illustration and a simplified top view illustration of the front housing as shown in  FIG. 4A ; 
         FIGS. 4D and 4E  are simplified sectional view illustrations of the front housing as shown in  FIGS. 4A-4C , taken along lines IVD-IVD and IVE-IVE in  FIGS. 4B and 4C , respectively; 
         FIG. 5A  is a simplified pictorial view illustration of a needle shield forming part of the AIDAHVM of  FIG. 1 ; 
         FIGS. 5B and 5C  are a simplified top view illustration and a simplified side view illustration of the needle shield as shown in  FIG. 5A ; 
         FIG. 5D  is a simplified sectional view illustration of the needle shield as shown in  FIGS. 5A-5C , taken along lines VD-VD in  FIG. 5B ; 
         FIG. 6A  is a simplified pictorial view illustration of a fixed sleeve forming part of the AIDAHVM of  FIG. 1 ; 
         FIGS. 6B and 6C  are a simplified top view illustration and a simplified side view illustration of the fixed sleeve as shown in  FIG. 6A ; 
         FIG. 6D  is a simplified sectional view illustration of the fixed sleeve as shown in  FIGS. 6A-6C , taken along lines VID-VID in  FIG. 6B ; 
         FIGS. 7A and 7B  are simplified pictorial view illustrations of a syringe sleeve forming part of the AIDAHVM of  FIG. 1 ; 
         FIGS. 7C and 7D  are a simplified top view illustration and a simplified side view illustration of the syringe sleeve as shown in  FIG. 7A ; 
         FIG. 7E  is a simplified sectional view illustration of the syringe sleeve as shown in  FIGS. 7A-7D , taken along lines VIIE-VIIE in  FIG. 7C ; 
         FIG. 8A  is a simplified pictorial view illustration of a plunger rod forming part of the AIDAHVM of  FIG. 1 ; 
         FIGS. 8B and 8C  are a simplified top view illustration and a simplified side view illustration of the plunger rod as shown in  FIG. 8A ; 
         FIG. 8D  is a simplified sectional view illustration of the plunger rod as shown in  FIGS. 8A-8C , taken along lines VIIID-VIIID in  FIG. 8B ; 
         FIG. 9A  is a simplified pictorial view illustration of a control unit forming part of the AIDAHVM of  FIG. 1 ; 
         FIGS. 9B and 9C  are a simplified side view illustration and a simplified top view illustration of the control unit as shown in  FIG. 9A ; 
         FIGS. 9D and 9E  are simplified sectional view illustrations of the control unit as shown in  FIGS. 9A-9C , taken along lines IXD-IXD and IXE-IXE, in  FIGS. 9B and 9C , respectively; 
         FIG. 10A  is a simplified pictorial view illustration of a rear housing forming part of the AIDAHVM of  FIG. 1 ; 
         FIGS. 10B and 10C  are a simplified side view illustration and a simplified top view illustration of the rear housing as shown in  FIG. 10A ; 
         FIG. 10D  is a simplified sectional view illustration of the rear housing as shown in  FIGS. 10A-10C , taken along lines XD-XD in  FIG. 10B ; 
         FIG. 11A  is a simplified pictorial view illustration of a Resilient Dampening Element (RDE) forming part of the AIDAHVM of  FIG. 1 ; 
         FIGS. 11B and 11C  are a simplified side view illustration and a simplified top view illustration of the RDE as shown in  FIG. 11A ; 
         FIG. 12A  is a simplified pictorial view illustration of a trigger button forming part of the AIDAHVM of  FIG. 1 ; 
         FIGS. 12B and 12C  are a simplified top view illustration and a simplified side view illustration of the trigger button as shown in  FIG. 12A ; 
         FIGS. 12D and 12E  are simplified sectional view illustrations of the trigger button as shown in  FIGS. 12A-12C , taken along lines XIID-XIID and XIIE-XIIE, in  FIGS. 12B and 12C , respectively; 
         FIG. 13A  is a simplified pictorial view illustration of the AIDAHVM of  FIGS. 1-12D  in a storage orientation; 
         FIG. 13B  is a simplified, partially cut away, top view illustration of the AIDAHVM as shown in  FIG. 13A ; 
         FIGS. 13C and 13D  are simplified sectional view illustrations of the AIDAHVM as shown in  FIG. 13A , taken along lines XIIIC-XIIIC and XIIID-XIIID, in  FIGS. 13B and 13C , respectively; 
         FIG. 14A  is a simplified pictorial view illustration of the AIDAHVM of  FIGS. 1-12D  in a first operative orientation, following RNS removal; 
         FIGS. 14B and 14C  are simplified sectional view illustrations of the AIDAHVM as shown in  FIG. 14A , taken along lines XIVB-XIVB and XIVC-XIVC, in  FIGS. 14A and 14B , respectively; 
         FIG. 15A  is a simplified pictorial view illustration of the AIDAHVM of  FIGS. 1-12D  in a second operative orientation, pushing against an injection site; 
         FIGS. 15B and 15C  are simplified sectional view illustrations of the AIDAHVM as shown in  FIG. 15A , taken along lines XVB-XVB and XVC-XVC, in  FIGS. 15A and 15B , respectively; 
         FIG. 16A  is a simplified pictorial view illustration of the AIDAHVM of  FIGS. 1-12D  in a third operative orientation, which is an activation orientation; 
         FIG. 16B  is a simplified top view illustration of the AIDAHVM as shown in  FIG. 16A ; 
         FIGS. 16C and 16D  are simplified sectional view illustrations of the AIDAHVM as shown in  FIGS. 16A-16B , taken along lines XVIC-XVIC- and XVID-XVID, in  FIGS. 16B and 16C , respectively; 
         FIG. 17A  is a simplified pictorial view illustration of the AIDAHVM of  FIGS. 1-12D  in a fourth operative orientation, including needle penetration, start of injection, injection and end of injection orientations; 
         FIGS. 17B and 17C  are simplified sectional view illustrations of the AIDAHVM as shown in  FIG. 17A  in a needle penetration operative orientation, taken along lines XVIIB-XVIIB and XVIIC-XVIIC, in  FIGS. 17A and 17B , respectively; 
         FIGS. 18A and 18B  are simplified sectional view illustrations of the AIDAHVM as shown in  FIG. 17A  in a start of injection operative orientation, along the same lines as  FIGS. 17B and 17C , respectively; 
         FIG. 19A  is a simplified, partially cut away, front view illustration of the AIDAHVM as shown in  FIG. 17A  in an injection operative orientation; 
         FIGS. 19B and 19C  are simplified sectional view illustrations of the AIDAHVM as shown in  FIG. 19A , taken along lines XIXB-XIXB and XIXC-XIXC, in  FIGS. 19A and 19B , respectively; 
         FIG. 20A  is a simplified, partially cut away, front view illustration of the AIDAHVM as shown in  FIG. 17A  in an end of injection operative orientation; 
         FIGS. 20B and 20C  are simplified sectional view illustrations of the AIDAHVM as shown in  FIG. 20A , taken along lines XXB-XXB and XXC-XXC, in  FIGS. 20A and 20B , respectively; 
         FIG. 21A  is a simplified pictorial view illustration of the AIDAHVM of  FIG. 1-12D  in a discard orientation; and 
         FIGS. 21B and 21C  are simplified sectional view illustrations of the AIDAHVM as shown in  FIG. 21A , taken along lines XXIB-XXIB and XXIC-XXIC, in  FIGS. 21A and 21B , respectively. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Reference is now made to  FIG. 1 , which is a simplified pictorial exploded view illustration of an Automatic Injection Device for Administration of High Viscosity Medication (AIDAHVM)  100  constructive and operative in accordance with a preferred embodiment of the invention and to  FIG. 13A , which is a simplified pictorial assembled view of the AIDAHVM of  FIG. 1  in a storage orientation. 
     As seen in  FIG. 1  and at least partially in  FIG. 13A , AIDAHVM  100  comprises an exterior Rigid Needle Shield (RNS) remover  200  at a forward end, an interior RNS remover  202  and a front housing  300 . Front housing  300  is preferably adapted to engage exterior RNS remover  200 . Preferably, when AIDAHVM  100  is assembled, exterior RNS remover  200  partially surrounds interior RNS remover  202 . Front housing  300  is preferably formed of a transparent material. In order to visually shield the internal mechanism of AIDAHVM  100  from a user, an opaque label  301  may cover the front housing  300 . 
     AIDAHVM  100  also includes a needle shield  400 , preferably configured to be forwardly inserted and movable relative to front housing  300 . A needle shield spring  402  is adapted to be inserted within needle shield  400  to bias movement of needle shield  400  relative to front housing  300 . A fixed sleeve  500  is configured to be inserted into needle shield  400  and engage needle shield spring  402 . A syringe sleeve  600 , positioned rearward of fixed sleeve  500 , is engaged therewith and movable relative thereto. 
     AIDAHVM  100  also includes a syringe  700 , typically a conventional syringe including a generally cylindrical storage container containing a material to be injected, typically a medication. Syringe  700  preferably includes a Rigid Needle Shield (RNS)  702 , typically a conventional RNS, a needle  707 , preferably adhesively attached to a forward end of syringe  700 , and a piston  708 , positioned within syringe  700  and generally disposed at a rearward end of syringe  700 . It is appreciated that the exact initial axial position of piston  708  within syringe  700  is not predetermined. Syringe  700  defines a flange  704  at a rearward end thereof. A resilient ring  706  is preferably attached to syringe sleeve  600 . 
     Syringe  700  is preferably operatively inserted into syringe sleeve  600 . A plunger rod  800  is configured to be operatively engaged with piston  708  of syringe  700 . 
     As seen further in  FIG. 1 , AIDAHVM also includes a control unit  900 , operatively engaged with plunger rod  800 , and at least one spring drive assembly. The at least one spring drive assembly includes an injection spring  902 , which is engaged at a forward end thereof with control unit  900  and at a rearward end thereof with a rear housing  1000 , and at least one selectably operable spring energy output force limiter, such as a resilient dampening element (RDE)  1100 , which is configured to be located within rear housing  1000  in operative engagement with control unit  900 . AIDAHVM  100  includes a trigger button  1200  at a rearmost portion thereof. 
     Reference is now made to  FIGS. 2A and 2B , which are simplified rear facing pictorial view and side view illustrations of exterior RNS (Rigid Needle Shield) remover  200  forming part of AIDAHVM  100  of  FIG. 1 , and to  FIGS. 2C and 2D , which are simplified sectional view illustrations of exterior RNS remover  200  as shown in  FIGS. 2A and 2B . 
     As seen in  FIGS. 2A-2D , exterior RNS remover  200  is an integrally formed element, preferably formed of plastic and arranged along a longitudinal axis  204 . Exterior RNS remover  200  preferably has a generally circular cylindrical configuration, including an outer cylindrical surface  206 , an inner cylindrical surface  207 , a forward end  208  and a rearward end  210 . Forward end  208  defines a circumferential ring  212 . Outer cylindrical surface  206  of exterior RNS remover  200  includes a tapered forward portion  214  and a generally cylindrical rearward portion  216 . The diameter of tapered forward portion  214  adjacent generally cylindrical rearward portion  216  is greater than the diameter thereof adjacent circumferential ring  212 . 
     A cylindrical wall portion  217  extends rearward from forward end  208  of exterior RNS remover  200 . Cylindrical wall portion  217  includes an outer surface  218  and an inner surface  220  which defines a cylindrical cavity  221 , including a forward cavity portion  222  and a rearward cavity portion  224  separated by an annular rearward facing flange  226 . The inner diameter of annular rearward facing flange  226  is less than the diameter of rearward cavity portion  224  and is also less than the diameter of forward cavity portion  222 . The diameter of rearward cavity portion  224  and the diameter of forward cavity portion  222  are typically equal. A rearward end of rearward cavity portion  224  includes an annular rearward facing flange  264 . 
     A rearward facing shoulder  234  is formed on inner cylindrical surface  207 , which divides an interior portion  228  of exterior RNS remover  200  outside of cylindrical cavity  221  into a forward annular cavity  230 , extending from front end  208  to rearward facing shoulder  234 , and a rearward annular portion  232 , extending from rearward facing shoulder  234  to rearward end  210 . The diameter of forward annular cavity  230  is less than the diameter of rearward annular portion  232 . 
     One or more, preferably two diametrically opposite, recessed portions  235  are formed in inner cylindrical surface  207  between rearward facing shoulder  234  and rearward end  210 . Recessed portion  235  is generally rectangular and includes an outwardly tapered portion  237  adjacent rearward end  210 . A generally rectangular axial protrusion  236  is formed on a portion of inner cylindrical surface  207  within recessed portion  235 . 
     Reference is now made to  FIGS. 3A-3C , which are, respectively, a simplified side view illustration, a simplified top view illustration and a simplified sectional view illustration of interior RNS (Rigid Needle Shield) remover  202 , forming part of AIDAHVM  100  of  FIG. 1 . 
     As seen in  FIGS. 3A-3C , interior RNS remover  202  is an integrally formed element, preferably formed of plastic and arranged along longitudinal axis  204 . Interior RNS remover  202  preferably has a generally cylindrical configuration, including an outer surface  238  and an inner surface  240 . Interior RNS remover  202  defines a forward end  242  and a rearward end  244 . 
     Forward end  242  of interior RNS remover  202  defines a circumferential ring  246 , including a rearwardly facing inner wall  248 . Outer surface  238  includes a forward portion  250  adjacent circumferential ring  246  and extending rearwardly to a first forwardly facing shoulder  252 . Outer surface  238  also includes an intermediate portion  254 , extending from first forwardly facing shoulder  252  to a second forwardly facing shoulder  256 , and a rearward portion  258 , extending from second forwardly facing shoulder  256  to rearward end  244 . 
     The diameter of the rearward portion  258  is greater than the diameter of intermediate portion  254  and the diameter of intermediate portion  254  is greater than the diameter of forward portion  250 . The diameter of circumferential ring  246  is greater than the diameter of forward portion  250 . 
     Interior RNS remover  202  also includes one or more, preferably two diametrically opposite, connectors  260  positioned on rearward portion  258 . Each connector  260  includes an inwardly radially extending arm  262 , preferably a resilient radially extending arm. 
     Reference is now made to  FIG. 4A , which is a simplified pictorial view illustration of front housing  300  forming part of AIDAHVM  100  of  FIG. 1 , and to  FIGS. 4B-4E , which are, respectively, a simplified top view illustration, a simplified side view illustration, and first and second simplified sectional view illustrations, of front housing  300  as shown in  FIG. 4A . 
     As seen in  FIGS. 4A-4E , front housing  300  is an integrally formed element having a generally cylindrical configuration, preferably formed of plastic and arranged along longitudinal axis  204 . 
     As described hereinabove, front housing  300  is preferably formed of a transparent material to enable a user to see, inter alia, the operative position of AIDAHVM  100 . As noted hereinabove, an opaque label  301  may be provided to cover portions of front housing  300  to visually shield the internal mechanism of AIDAHVM  100  from a user. Alternatively, front housing  300  may be opaque and include a transparent window allowing visual access to at least a body of syringe  700 , to enable a user to see the operative position of AIDAHVM  100 . 
     Front housing  300  includes an outer housing surface  302 , an inner housing surface  304 , a forward housing end  306  and a rearward housing end  308 . Front housing  300 , includes a relatively short forward portion  310  and a relatively long rearward portion  312 . A forwardly facing shoulder  318  is defined between relatively short forward portion  310  and relatively long rearward portion  312 . The diameter of relatively long rearward portion  312  is greater than the diameter of relatively short forward portion  310 . 
     Relatively long rearward portion  312  includes a forward end  320  adjacent forwardly facing shoulder  318 . 
     At least one resilient arm  322  is positioned on relatively short forward portion  310 . Resilient arm  322  extends radially inwardly and, as seen particularly in FIG.  4 E, includes an internally extending protrusion  324 , having an inwardly tapered surface  326  and a forward facing edge  328 . 
     As seen particularly in  FIG. 4E , at least one, and preferably two diametrically opposite, elongate slots  330  are formed on inner housing surface  304  of relatively long rearward portion  312  of front housing  300 . Elongate slots  330  are arranged parallel to longitudinal axis  204  and extend rearwardly from forward end  320  along long rearward portion  312 . 
     Elongate slots  330  each define an internal T-shaped recess  332 , which includes a forward inner cavity portion  334  and a rearward inner cavity portion  335 . The width of rearward inner cavity portion  335  is greater than the width of forward inner cavity portion  334 . Extending rearwardly from forward end  320  are one or more, preferably two opposite facing, elongate elements  336  spaced from each other. Elongate elements  336  partially cover forward inner cavity portion  334 . 
     An aperture  342  is formed in front housing  300  at a rearward end of rearward inner cavity portion  335 . 
     One or more longitudinal ribs  338  are formed on inner housing surface  304  of relatively long rearward portion  312  of front housing  300 . Longitudinal ribs  338  are arranged parallel to longitudinal axis  204  and typically extend rearwardly from forward end  320  along relatively long rearward portion  312 . As seen in  FIGS. 4D and 4E , longitudinal ribs  338  preferably extend only partially along the length of relatively long rearward portion to rearward housing end  308 . 
     Relatively long rearward portion  312  of front housing  300  also preferably includes one or more, preferably two diametrically opposite, forward apertures  340  extending longitudinally and arranged parallel to axis  204 . One or more, preferably two diametrically opposite, radially extending rearward apertures  341  are also formed on relatively long rearward portion  312  of front housing  300 . Forward apertures  340  and rearward apertures  341  are mutually aligned along front housing  300  parallel to longitudinal axis  204 . One or more rearward apertures  344  are also formed on relatively long rearward portion  312  of front housing  300  and are disposed at a radial distance of generally 90° relative to forward apertures  340  and rearward apertures  341 . As seen in  FIG. 4E , apertures  342  and rearward apertures  344  are preferably mutually aligned parallel to longitudinal axis  204 . 
     Reference is now made to  FIG. 5A , which is a simplified pictorial view illustration of needle shield  400  forming part of AIDAHVM  100  of  FIG. 1 , and to  FIGS. 5B-5D , which are, respectively, a simplified top view illustration, a simplified side view illustration and a simplified sectional view illustration of needle shield  400  as shown in  FIG. 5A . 
     As seen in  FIGS. 5A-5D , needle shield  400  is an integrally formed element of a generally cylindrical shape, preferably formed of plastic and arranged along longitudinal axis  204 , having an outer surface  404  and an inner surface  406 , and defining a forward end  408  and a rearward end  410 . Needle shield  400  preferably includes a forward portion  412  and a rearward portion  414 . Preferably, the diameter of rearward portion  414  is greater than the diameter of forward portion  412 . Forward portion  412  extends rearwardly from forward end  408  to a forward facing shoulder  416  and rearward portion  414  extends rearwardly from forward facing shoulder  416  to rearward end  410 . 
     A radially extending circumferential ring  418  extends inwardly and rearwardly from forward end  408 . Circumferential ring  418  defines a rearward facing edge  419  adjacent inner surface  406  of needle shield  400 . An opening  420  extends rearwardly from circumferential ring  418  and is arranged parallel to longitudinal axis  204 . 
     Needle shield  400  also includes one or more, preferably two, recessed portions  422  arranged rearwardly of rearward facing edge  419 . One or more, preferably two, longitudinal openings  424  extend rearwardly from a point on forward portion  412  to rearward portion  414 , each including a rearward edge  425 . Needle shield  400  also includes one or more, preferably two, longitudinal indication openings  426 , each extending rearwardly from a location rearward of recessed portion  422  on forward portion  412  to rearward portion  414 . 
     Needle shield  400  further includes one or more first apertures  428 , each located rearwardly of each of the one or more longitudinal openings  424 . One or more second apertures  430  are also provided, each located rearwardly of each of the one or more indication openings  426 . 
     In a most preferred embodiment, two longitudinal openings  424  are provided and are aligned with two first apertures  428 . In this embodiment, longitudinal openings  424  are disposed at a radial distance of generally 90° relative to two indication openings  426 , each of which are aligned with second apertures  430 . 
     One or more longitudinal grooves  432  are formed on outer surface  404  of the rearward portion  414 . Longitudinal grooves  432  extend rearwardly from forward facing shoulder  416  and typically cover most of the length of rearward portion  414 . 
     Extending rearwardly from rearward end  410  are one or more, preferably two, tabs  434 , each defining an inner surface  435  and having an aperture  436  therethrough. Tabs  434  are preferably positioned rearward of longitudinal openings  424  and at a radial distance of generally 90° relative to recessed portions  422  and indication openings  426 . 
     Reference is now made to  FIG. 6A , which is a simplified pictorial view illustration of fixed sleeve  500  forming part of AIDAHVM  100  of  FIG. 1 , and to  FIGS. 6B-6D , which are, respectively, a simplified top view illustration, a simplified side view illustration and a simplified sectional view illustration of fixed sleeve  500  as shown in  FIG. 6A . 
     As seen in  FIGS. 6A-6D , fixed sleeve  500  is an integrally formed element having a generally cylindrical shape, preferably formed of plastic and arranged along longitudinal axis  204 . 
     The fixed sleeve  500  includes an outer surface  502  and an inner surface  504 , and defines a forward end  506  and a rearward end  508 . Fixed sleeve  500  includes a forward cylindrical portion  510  and a rearward cylindrical portion  512 . The diameter of forward cylindrical portion  510  is preferably greater than the diameter of rearward cylindrical portion  512 . Forward cylindrical portion  510  preferably extends rearwardly from forward end  506  to a rearward facing shoulder  514  and rearward cylindrical portion  512  extends rearwardly from rearward facing shoulder  514  to rearward end  508 . Forward cylindrical portion  510  defines a forward inner bore  516  and rearward cylindrical portion  512  defines a rearward inner bore  518 . The diameter of forward inner bore  516  is greater than the diameter of rearward inner bore  518 . 
     A circumferential ring  520  extends radially outwardly from forward end  506  and preferably includes one or more, preferably two diametrically opposite, radially extending protrusions  522 . 
     Positioned rearwardly of each of radially extending protrusions  522  is a forwardly facing edge  523 . A forward longitudinal rib  524  extends rearwardly from each forwardly facing edge  523  to a rearwardly facing edge  515  positioned adjacent and forwardly of rearward facing shoulder  514 . Forward longitudinal ribs  524  include a top, generally planar portion, and a bottom portion, generally in the shape of a rectangular prism, including a generally wide forward portion  526  adjacent to the forwardly facing edge  523  and a generally narrow rearward portion  528  adjacent the rearward facing shoulder  514 . Generally narrow rearward portion  528  of forward longitudinal rib  524  and top, generally planar, portion of forward longitudinal rib  524  define a gap therebetween. Extending outwardly from a rearward end of top, generally planar, portion of the forward longitudinal ribs  524  is a radial extension  530 . 
     The provision of radial extension  530  and the gap between the top, generally planar, portion of forward longitudinal rib  524  and the narrow rearward portion  528  provide for a resilient characteristic of the longitudinal ribs  524 . 
     One or more rearward longitudinal ribs  532  extend forwardly from rearward end  508  of fixed sleeve  500  to rearward facing shoulder  514 . The rearward longitudinal ribs  532  are arranged parallel to longitudinal axis  204  and aligned with the forward longitudinal ribs  524 . 
     One or more longitudinal indication openings  536  extend forwardly from an edge  538  disposed adjacent to and forwardly of the rearward end  508  of fixed sleeve  500  to an edge  540  disposed adjacent to and rearwardly of forward end  506  of fixed sleeve  500 . 
     One or more, preferably two, protrusions  542  are disposed at opposite edges of each indication opening  536 . Protrusions  542  extend radially outwardly from forward cylindrical portion  510  of fixed sleeve  500 . Protrusions  542  extend forwardly from rearward facing shoulder  514  along a portion of the length of forward cylindrical portion  510  of fixed sleeve  500 . 
     Reference is now made to  FIGS. 7A and 7B , which are simplified pictorial view illustrations of syringe sleeve  600  forming part of AIDAHVM  100  of  FIG. 1 , and to  FIGS. 7C-7E , which are, respectively, a simplified top view illustration, a simplified side view illustration and a simplified sectional view illustration of syringe sleeve  600  as shown in  FIGS. 7A and 7B . 
     As seen in  FIGS. 7A-7E , syringe sleeve  600  is an integrally formed element having a generally cylindrical shape, preferably formed of plastic and arranged along the longitudinal axis  204 . 
     Syringe sleeve  600  includes an outer surface  602  and an inner surface  604 , and defines a forward end  606  and a rearward end  608 . The syringe sleeve  600  includes a cylindrical wall  609 . 
     One or more, typically two, longitudinal openings  610  extend rearwardly, arranged parallel to longitudinal axis  204 , from forward end  606  partially through the length of cylindrical wall  609 . Each longitudinal opening  610  defines a rearward edge  612  and two opposed lateral edges  614 . 
     One or more, preferably two, angular protrusions  616  are disposed on opposed lateral edges  614  of longitudinal opening  610 . Angular protrusions  616  include a straight edge  618 , parallel to and radially extending outwardly from forward end  606  and an inclined edge  620 , between the outward end of straight edge  618  and cylindrical wall  609 . 
     Syringe sleeve  600  also includes one or more, typically two, forward resilient arms  622 , preferably disposed at a radial distance of generally 90° relative to longitudinal openings  610  and arranged parallel to longitudinal axis  204 . Resilient arms  622  preferably include a forward extending portion  624 , extending forwardly from rearward end  608 , a connecting portion  626 , arranged perpendicularly to forward extending portion  624 , and a rearward facing portion  628 , which extends rearwardly from connecting portion  626  and is arranged parallel to longitudinal axis  204 . Rearward facing portion  628  terminates in a T-shape portion  630  on which is formed an extending protrusion  632 . 
     Extending radially inwardly from rearward end  608  is a circumferential ring  634 , which defines an inner forwardly facing surface  638  abutting inner surface  604  of syringe sleeve  600 . Cylindrical wall  609  and circumferential ring  634  define a bore  636  extending longitudinally through syringe sleeve  600  and parallel to longitudinal axis  204 . 
     One or more, preferably two diametrically opposite, rearward resilient arms  640  extend longitudinally rearwardly, arranged in the axial direction of longitudinal axis  204  and at a radial distance of generally 90° relative to forward resilient arms  622 . Rearward resilient arms  640  extend rearwardly from a point adjacent circumferential ring  634 . A radially inwardly extending protrusion  642  is formed at a rearward end of rearward resilient arm  640 . Rearward resilient arms  640  include an outer surface  644 , an inner surface  646  and a recess  648  formed on a rearward portion of outer surface  644 . 
     One or more, preferably two, guide grooves  650  extend longitudinally and are arranged parallel to longitudinal axis  204 . Guide grooves  650  extend along inner surface  604  from forward end  606  to the vicinity of rearward end  608 . 
     Reference is now made to  FIG. 8A , which is a simplified pictorial view illustration of plunger rod  800  forming part of AIDAHVM  100  of  FIG. 1 , and to  FIGS. 8B-8D , which are, respectively, a simplified top view illustration, a simplified side view illustration and a simplified sectional view illustration of plunger rod  800  as shown in  FIG. 8A . 
     As seen in  FIGS. 8A-8D , plunger rod  800  is an integrally formed element, preferably formed of plastic and arranged along longitudinal axis  204 . Plunger rod  800  includes an outer surface  802  and has a forward end  804  and a rearward end  806 . Forward end  804  of plunger rod  800  includes a forwardly extending protrusion  808  formed thereon. 
     Extending rearwardly from rearward end  806  is a substantially hollow rear portion  810  defining a rearward edge  811 . Extending rearwardly from substantially hollow rear portion  810  are one or more, typically two, extension tabs  812 . A recess  814  is formed in substantially hollow rear portion  810 . 
     One or more, typically two, longitudinal guide ribs  816  are formed on an outer surface of substantially hollow rear portion  810 . Longitudinal guide ribs  816  extend parallel to axis  204  along substantially hollow rear portion  810 . Substantially hollow rear portion  810  also includes one or more, typically two, protrusions  818  formed thereon, preferably disposed at a radial distance of generally 90° relative to longitudinal guide ribs  816 . Preferably, protrusions  818  include a rearward facing inclined surface  820 . 
     Reference is now made to  FIG. 9A , which is a simplified pictorial view illustration of control unit  900  forming part of AIDAHVM  100  of  FIG. 1 , and to  FIGS. 9B-9E , which are, respectively, a simplified side view illustration, a simplified top view illustration, and simplified sectional view illustrations of control unit  900  as shown in  FIG. 9A . 
     As seen in  FIGS. 9A-9E , control unit  900  is an integrally formed element, preferably formed of plastic and arranged along the longitudinal axis  204 . 
     Control unit  900  includes a forward circumferential ring  903 , connected by one or more, preferably two, rearward extending arms  904  to a rearward body portion  906 . Forward circumferential ring  903  defines a rearward ring end  908  and a forward ring end  910 . Rearward extending arms  904  define an inner surface  905  and an outer surface  907 . 
     One or more, typically two, forward resilient arms  912  extend forwardly from forward ring end  910  and are arranged parallel to longitudinal axis  204 . Forward resilient arms  912  define a forward end  914 , an inner surface  916  and an outer surface  918 . A longitudinal groove  913  extends along the entire length of rearward extending arm  904  and continues along the entire length of forward resilient arm  912 . 
     Disposed within longitudinal groove  913 , in the vicinity of forward end  914 , along an axis that is perpendicular to longitudinal axis  204 , is a radially inwardly extending protrusion  920 . Forward resilient arm  912  also defines two edges  915  and  917  on opposite side of longitudinal groove  913 . 
     Edges  915  and  917  include lateral protrusions  922  adjacent forward end  914  and extending rearwardly therefrom. 
     Extending radially outwardly from outer surface  918  of each of forward resilient arms  912  is an external protrusion  924 , disposed in vicinity of forward end  914 . 
     Each of rearward extending arms  904  defines a rearward facing edge  926 . Abutting rearward facing edges  926  are inwardly radially extending rearward protrusions  928 . 
     Rearward body portion  906  of control unit  900  includes one or more, preferably two diametrically opposite, forward facing portions  929 , one or more, preferably two diametrically opposite, intermediate portions  932  and a generally annular end portion  934 . Preferably, generally annular end portion  934  includes two slightly elongate sections at locations diametrically opposite one another and is connected, at a forward end thereof along the elongate sections, to intermediate portions  932 , which are in turn connected, at a forward end, to forward facing portions  929 . 
     Forward facing portions  929  preferably include a rearward portion  933  and a forward portion  935 , which preferably include a common inner wall section. One or more recesses  937  are formed in an outer wall of forward portion  935 . 
     One or more, preferably two diametrically opposite, resilient arms  930  extend forwardly from generally annular end portion  934 , preferably parallel to longitudinal axis  204  and forward resilient arms  912 , at a radial distance of generally 90° relative to the elongate sections of generally annular end portion  934 . 
     Resilient arm  930  defines an outer surface  938  and an inner surface  940 . An inwardly radially extending protrusion  942  extends from inner surface  940  of resilient arm  930  near a forward end thereof. Forward of inwardly radially extending protrusion  942 , resilient arm  930  terminates in an inclined surface  936 . 
     An intermediate outer surface  944  is defined between forward facing portion  929  and intermediate portion  932  on two opposite sides of rearward body portion  906  that are orthogonal to the plane of connecting resilient arms  930 . Preferably, extending radially outwardly from generally annular end portion  934  are one or more, preferably four, rearward protrusions  946 . Preferably, a pair of rearward protrusions  946  are located on generally annular end portion  934  adjacent opposite lateral ends of each of resilient arms  930 . 
     Preferably, extending radially outwardly from generally annular end portion  934  are also preferably formed a pair of spaced protrusions  948 . Spaced protrusions  948  extend forwardly from generally annular end portion  934  to a rearward portion of intermediate outer surface  944  of intermediate portions  932 . Generally annular end portion  934  and intermediate portion  932  form an inclined surface  949  therebetween. Preferably, spaced protrusions  948  are disposed at a radial distance of generally 90° relative to inwardly radially extending protrusions  942 . 
     Each of forward facing portions  929  preferably defines a forward facing shoulder  950 . Forward facing shoulders  950  are disposed slightly forwardly of inwardly radially extending protrusions  942 , and disposed at a radial distance of generally 90° relative to inwardly radially extending protrusions  942 . 
     Reference is now made to  FIG. 10A , which is a simplified pictorial view illustration of rear housing  1000  forming part of AIDAHVM  100  of  FIG. 1 , and to  FIGS. 10B-10D , which are, respectively, a simplified side view illustration, a simplified top view illustration and a simplified sectional view illustration of rear housing  1000  as shown in  FIG. 10A . 
     As seen in  FIGS. 10A-10D , rear housing  1000  is an integrally formed element, preferably formed of plastic and arranged along the longitudinal axis  204 . 
     Rear housing  1000  preferably includes an outer cylindrical portion  1002  and an inner cylindrical portion  1004  connected by a circumferential ring  1006 . Inner cylindrical portion  1004  defines an outer surface  1008 , an inner surface  1010  and a forward end  1012 . Circumferential ring  1006  defines a forward facing annular edge surface  1014 . The outer cylindrical portion  1002  defines an outer surface  1016  and a rearward end  1018 . 
     Outer cylindrical portion  1002  rearwardly extends from forward facing annular edge surface  1014  to rearward end  1018 . A circumferential ring  1020  is formed rearward of and adjacent to rearward end  1018 . 
     One or more, preferably two diametrically opposite, radially outwardly extending protrusions  1022  are formed on outer surface  1016  of outer cylindrical portion  1002 . Protrusions  1022  are preferably arranged perpendicular to longitudinal axis  204 . 
     One or more, preferably two diametrically opposite, openings  1024  extend radially through outer cylindrical portion  1002 , disposed at a radial distance of generally 90° relative to protrusions  1022 . 
     Inner cylindrical portion  1004  is substantially hollow, open at forward end  1012  and partially closed at a rearward end by a circumferential flange  1026 , defining an inner forwardly facing surface  1028 , an outer rearwardly facing edge  1029 , and an opening  1027  extending longitudinally rearwardly from the outer rearwardly facing edge  1029 . 
     One or more, preferably two diametrically opposite, resilient arms  1030  are disposed in one or more, preferably two diametrically opposed, hollow portions of inner cylindrical portion  1004  rearward of forward facing annular edge surface  1014 . Resilient arms  1030  extend forwardly from the circumferential flange  1026  of the inner cylindrical portion  1004 . 
     Resilient arms  1030  include a T-shaped forward end  1032 , defining two lateral extensions  1034  disposed therealong. One or more, preferably two, spaced radially outward protrusions  1038  are formed on an outer surface  1036  of resilient arms  1030  adjacent forward end  1032 . 
     Reference is now made to  FIG. 11A , which is a simplified pictorial view illustration of Resilient Dampening Element (RDE)  1100  forming part of AIDAHVM  100  of  FIG. 1 , and to  FIGS. 11B-11C , which are, respectively, a simplified side view illustration and a simplified top view illustration of RDE  1100  as shown in  FIG. 11A . 
     As seen in  FIGS. 11A-11C , RDE  1100  is an integrally formed elongate element arranged along longitudinal axis  204 . RDE  1100  is preferably formed of thermoplastic material, such as polyethylene, or any other suitable material that allows either plastic extension or elastic extension or both. 
     RDE  1100  preferably includes a forward holding portion  1102 , an intermediate dampening portion  1104  and a rearward holding portion  1106 , arranged longitudinally along longitudinal axis  204 . 
     As seen in  FIGS. 11A-11C , the cross-sectional area of intermediate dampening portion  1104  is substantially less than the cross-sectional area of both the forward holding portion  1102  and the rearward holding portion  1106 . 
     Forward holding portion  1102  of RDE  1100  defines a forward end  1108 , and rearward holding portion  1106  defines a rearward end  1110 . Forward holding portion  1102  extends rearwardly from forward end  1108  to a rearward facing edge  1112  and rearward holding portion  1106  defines a forward facing edge  1114 . 
     Rearward holding portion  1106  and forward holding portion  1102  are connected by intermediate dampening portion  1104 , which is disposed longitudinally between rearward facing edge  1112  of the forward holding portion  1102  and the forward facing edge  1114  of the rearward holding portion  1106 . 
     Forward holding portion  1102  includes a forward broadened section  1116  defining a rearward facing edge  1118 , an intermediate section  1120 , extending rearwardly therefrom, and an annular flange  1122 , disposed rearwardly of intermediate section  1120 . The cross-sectional area of intermediate section  1120  is less than the cross-sectional area of forward broadened section  1116 . Forward broadened section  1116  and annular flange  1122  are typically of equal cross-sectional area and are spaced apart by intermediate section  1120 . 
     Formed on forward facing edge  1114  is a forward extending projection  1124  arranged along longitudinal axis  204 . Forward extending projection  1124  defines a forward facing edge  1126 . One or more, preferably two diametrically opposite, protrusions  1128  are disposed on forward facing edge  1126 . Protrusions  1128  preferably extend in a forward direction from forward facing edge  1126  and radially outwardly relative to axis  204 . 
     Reference is now made to  FIG. 12A , which is a simplified pictorial view illustration of trigger button  1200  forming part of AIDAHVM  100  of  FIG. 1 , and to  FIGS. 12B-12E , which are, respectively, a simplified top view illustration, a simplified side view illustration and simplified sectional view illustrations of trigger button  1200  as shown in  FIG. 12A . 
     As seen in  FIGS. 12A-12E , trigger button  1200  is an integrally formed element, preferably formed of plastic and arranged along longitudinal axis  204 . 
     Trigger button  1200  has a generally cylindrical configuration and defines an inner surface  1202 , an outer surface  1204 , an open forward end  1206  and a closed rearward end  1208 . 
     Extending radially outward from outer surface  1204  are one or more circumferentially spaced projections  1210 . Adjacent each of projections  1210 , an elongate longitudinal recess  1211  is typically formed in outer surface  1204 . 
     Extending rearwardly from forward end  1206  are one or more, preferably two diametrically opposite, hollow generally rectangular recesses  1212 . 
     One or more, preferably two, longitudinal resilient projections  1214  extend forwardly from closed rearward end  1208 . Longitudinal resilient projections  1214  and generally rectangular recesses  1212  are aligned along a mutual axis that is preferably perpendicular to longitudinal axis  204 . 
     Extending longitudinally forward from closed rearward end  1208  to forward end  1206  are one or more, preferably four circumferentially spaced, guide ribs  1216 . Guide ribs  1216  are preferably arranged along axis  204  and parallel to the longitudinal resilient projections  1214 . 
     Reference is now made to  FIG. 13A , which is a simplified pictorial view illustration of the AIDAHVM of  FIG. 1  in a storage orientation, and to  FIGS. 13B-13D , which are, respectively, a simplified top view illustration and simplified sectional view illustrations of the AIDAHVM as shown in  FIG. 13A . 
     As seen in  FIGS. 13A-13D , AIDAHVM  100  is in a locked storage orientation, in which relative axial movement between the components thereof is prevented, except as described hereinbelow. In the locked storage orientation shown in  FIGS. 13A-13D , needle  707  of syringe  700  is covered by RNS  702 . 
     As seen in  FIGS. 13A-13D , fixed sleeve  500  is disposed within front housing  300  and is attached thereto by means of engagement of the forward longitudinal ribs  524  of the fixed sleeve  500  within elongate slots  330  of front housing  300 . Forward longitudinal ribs  524  are inserted within the forward inner cavity portion  334  and are held within by the elongate elements  336 . Radial extensions  530  of the forward longitudinal ribs  524  are fixedly held within the apertures  342  of the front housing  300  and limit rearward axial movement of the fixed sleeve  500  relative to the front housing  300 . The forwardly facing edge  523  of the forward longitudinal ribs  524  of the fixed sleeve  500  abuts the forward end  320  of the relatively long rearward portion  312  of the front housing and thus prevents forward axial movement of the fixed sleeve  500  relative to the front housing  300 . 
     In the storage orientation seen in  FIGS. 13A-13D , spring  402  is compressed and fixedly held between forward end  506  of the fixed sleeve  500  at its rearward end and rearward facing edge  419  of needle shield  400  at its forward end. Axial forward movement of needle shield  400  relative to front housing  300  under the urging of spring  402  is prevented by the engagement of internally extending protrusion  324  of the resilient arms  322  of the front housing  300  with recessed portions  422  of needle shield  400 . The engagement of internally extending protrusion  324  with recessed portions  422  is achieved by the inwardly tapered surface  326  and the forward facing edge  328  forming a stop with recessed portions  422  of needle shield  400 . Resilient arms  322  of front housing  300  are supported at their outer surface by rectangular axial protrusions  236  of exterior RNS remover  200 . 
     The engagement of the resilient arms  322  of the front housing  300  with the recessed portions  422  of the needle shield  400  in the storage orientation maintains the distance between the forward end  306  of the front housing  300  and the forward end  408  of the needle shield  400 , and thereby the length of the AIDHVM  100 , at a minimum. The distance between the forward end  306  of the front housing  300  and the forward end  408  of the needle shield  400 , and thereby the length of the AIDHVM  100 , is increased only following the removal of the exterior RNS remover  200  and the interior RNS remover  202 , which disengages resilient arms  322  of front housing  300  from recessed portions  422  of needle shield  400 , as described further hereinbelow with reference to  FIGS. 14A-14C . 
     Interior portion  228  of exterior RNS remover  200  surrounds relatively short forward portion  310  of front housing  300  and forward cavity  230  of exterior RNS remover  200  partially surrounds the forward portion  412  of the needle shield  400 . Cylindrical wall portion  217  is positioned within the opening  420  of needle shield  400 . Interior RNS remover  202  is positioned partially within the forward cavity portion  222  and partially within the rearward cavity portion  224  of cylindrical cavity  221  of exterior RNS remover  200 . 
     Annular rearward facing flange  226  of exterior RNS remover  200  is movably positioned along the length of the forward portion  250  between the first forwardly facing shoulder  252  and the circumferential ring  246  of the interior RNS remover  202 . This relative arrangement between the annular rearward facing flange  226  of the exterior RNS remover  200  and the forward portion  250  of the interior RNS remover  202  allows limited axial relative movement between the interior RNS remover  202  and the exterior RNS remover  200 , along the length defined between the circumferential ring  246  and the first forwardly facing shoulder  252 , to compensate for tolerance inaccuracies of AIDHVM  100  and syringe  700  that may result from the manufacturing process. 
     Interior RNS remover  202  fixedly holds RNS  702  within. RNS  702  is held at a forward end by rearward facing inner wall  248 . A rearward side of RNS  702  is snap-fit into inwardly radially extending arms  262  of connectors  260  of interior RNS remover  202 . Additionally, interior RNS remover  202  is partially inserted into the forward inner bore  516  of the fixed sleeve  500 . 
     Syringe  700  is located within bore  636  of syringe sleeve  600  and rearward inner bore  518  of fixed sleeve  500 . Syringe  700  is fixedly held relative to syringe sleeve  600  by situating flange  704  of syringe  700  forward of radial protrusions  642  of rearward resilient arm  640  of syringe sleeve  600 , between radial protrusions  642  and resilient ring  706 , attached to rearward end  608  of syringe sleeve  600 . 
     The longitudinal opening  610  of the syringe sleeve  600  and the longitudinal indication opening  536  of the fixed sleeve  500  are positioned to allow visual examination of the contents of syringe  700  through transparent portion of front housing  300 . Needle  707  of the syringe  700  is fixedly attached to the syringe  700 , preferably by use of an adhesive material. 
     Rearward longitudinal ribs  532  of the fixed sleeve  500  are inserted into guide grooves  650  of the syringe sleeve  600 , to ensure proper alignment between the fixed sleeve  500  and the syringe sleeve  600 . Engagement of ribs  532  and guide grooves  650  allows relative axial movement and prevents relative rotational movement between fixed sleeve  500  and syringe sleeve  600 . 
     Relative axial movement between syringe sleeve  600  and control unit  900  is prevented by engagement of radially inwardly extending protrusions  920  of forward resilient arms  912  of control unit  900  with recesses  648  of rearward resilient arms  640  of syringe sleeve  600 . External protrusions  924  of forward resilient arms  912  engage inner surface  406  of the needle shield  400  to prevent radially outward movement of forward resilient arms  912 . 
     Spring  902  is compressed and fixedly held between rearward ring end  908  of the forward circumferential ring  903  of the control unit  900  at a forward end and by forward facing annular edge surface  1014  of the rear housing  1000  at a rearward end thereof. Axial forward movement of control unit  900 , under urging of spring  902  is prevented by engagement of spaced protrusions  948  of intermediate portion  932  of rearward body portion  906  of control unit  900  with lateral extensions  1034  of the resilient arms  1030  of the rear housing  1000 . Spaced radially outward protrusions  1038  of resilient arms  1030  engage inner surface  435  of needle shield  400  to prevent radially outward movement of resilient arms  1030 . 
     Relative axial movement between rear housing  1000  and front housing  300  is prevented by insertion of protrusions  1022  of the outer cylindrical portion  1002  of the rear housing  1000  into rearward apertures  341  of front housing  300 . 
     RDE  1100  is inserted into the opening  1027  of the rear housing  1000 . Forward axial movement of RDE  1100  relative to rear housing  1000  is prevented by engagement of forward facing edge  1114  of RDE  1100  with outer rearwardly facing edge  1029  of circumferential flange  1026  of rear housing  1000 . Rearward axial movement of RDE  1100  relative to rear housing  1000  is prevented by engagement of protrusions  1128  of RDE  1100  with inner forwardly facing surface  1028  of circumferential flange  1026  of the rear housing  1000 . 
     Rearward facing edge  1118  of forward broadened section  1116  of RDE  1100  is disposed forwardly of inwardly radially extending protrusions  942  of connecting resilient arms  930  of control unit  900 . Forward broadened section  1116  of RDE  1100  is located within recess  814  of plunger rod  800 . 
     Inclined surfaces  936  of connecting resilient arms  930  of the control unit  900  are positioned against the rearward facing inclined surfaces  820  of the diametrically opposite protrusions  818  of the plunger rod  800 . Forward axial movement of plunger rod  800  is prevented by inwardly radially extending rearward protrusions  928  of the control unit  900  and rearward axial movement of plunger rod  800  is prevented by engagement of rearward facing inclined surfaces  820  of plunger rod  800  with inclined surfaces  936  of resilient arms  930  of control unit  900 . 
     As seen particularly in  FIGS. 13C and 13D , in the storage orientation, forward end  804  of plunger rod  800  is inserted into syringe  700  and is rearwardly spaced from piston  708  of syringe  700 . 
     Outer surface  1204  of trigger button  1200  is positioned between the outer cylindrical portion  1002  and the inner cylindrical portion  1004  of the rear housing  1000 , while the circumferentially spaced projections  1210  of the trigger button  1200  are disposed within openings  1024  of the outer cylindrical portion  1002  of the rear housing  1000 . Rearward axial movement of trigger button  1200  relative to rear housing  1000  is prevented by location of projections  1210  of trigger button  1200  within openings  1024  of rear housing  1000 . 
     Longitudinal resilient projections  1214  of the trigger button  1200  are disposed between forward facing portions  929  of rearward body portion  906  of control unit  900  and between diametrically opposite resilient arms  1030  of rear housing  1000 . Forward axial movement of trigger button  1200  relative to rear housing  1000  is prevented by the location of the forward end of longitudinal resilient projections  1214  abutting inclined surface  949  of intermediate portion  932  of control unit  900 . 
     It is appreciated that, if enabled, pressing the closed rearward end  1208  of the trigger button  1200  forwardly would, as described further hereinbelow, force longitudinal resilient projections  1214  of trigger button  1200  to slide over inclined surface  949  of intermediate portion  932  of control unit  900  and bend radially outwardly and thereby push resilient arms  1030  of the rear housing  1000  radially outwardly relative to the spaced protrusions  948  of control unit  900 . However, in the storage orientation seen in  FIGS. 13A-13D , forward movement of trigger button  1200  is prevented by the location of inner surface  435  of needle shield  400  adjacent to and radially outwardly of spaced radially outward protrusions  1038  of the rear housing  1000  which prevents radially outward movement of spaced radially outward protrusions  1038  of the rear housing  1000 . 
     Reference is now made to  FIG. 14A , which is a simplified pictorial view illustration of AIDAHVM  100  in a first operative orientation following RNS removal and to  FIGS. 14B-14C , which are simplified sectional view illustrations of the AIDAHVM as shown in  FIG. 14A . 
     As seen in  FIGS. 14A-14C , RNS  702  has been removed by forward axial displacement of exterior RNS remover  200  and interior RNS remover  202  relative to AIDAHVM  100 , typically by a user pulling exterior RNS remover forwardly relative to front housing  300 , thereby exposing needle shield  400  and needle  707 . 
     In a first stage of the forward axial displacement of exterior RNS remover  200 , exterior RNS remover  200  is forwardly axially displaceable relative to both front housing  300  and to interior RNS remover  202 . The first stage continues until annular rearward facing flange  226  of exterior RNS remover  200  engages circumferential ring  246  of interior RNS remover  202 . 
     In a second stage of the forward axial displacement of exterior RNS remover  200 , exterior RNS remover  200  is forwardly axially displaceable relative to front housing  300  but is not forwardly axially displaceable relative to interior RNS remover  202 . The second stage begins with the engagement of annular rearward facing flange  226  of exterior RNS remover  200  with circumferential ring  246  of interior RNS remover  202 . During the second stage, exterior RNS remover  200  and interior RNS remover  202  are forwardly axially displaced together relative to front housing  300 . During the second stage, engagement of RNS  702  by inwardly radially extending arms  262  of connectors  260  of interior RNS remover  202  also forwardly axially displaces RNS  702 , thereby removing RNS  702  from syringe  700 . 
     Following the removal of the exterior RNS remover  200 , rectangular axial protrusions  236  of the exterior RNS remover  200  no longer support resilient arms  322  of the front housing  300 . This allows for the inwardly tapered surface  326  of resilient arms  322  of front housing  300  are thereby free to slide over inclined surface of recessed portions  422  of needle shield  400  and thereby radially outwardly open, allowing forward movement of needle shield  400  under the urging of spring  402 . 
     Under the urging of spring  402 , needle shield  400  proceeds forwardly relative to front housing  300  until rearward edges  425  of longitudinal openings  424  of needle shield  400  engage extending protrusions  632  of forward resilient arms  622  of syringe sleeve  600 . 
     As seen in  FIGS. 14A-14C , in the first operative orientation, spaced radially outward protrusions  1038  of diametrically opposite resilient arms  1030  of rear housing  1000  are still radially supported by inner surface  435  of tabs  434  of needle shield  400 . 
     Reference is now made to  FIG. 15A , which is a simplified pictorial view illustration of AIDAHVM  100  in a second operative orientation, pushing against an injection site and to  FIGS. 15B and 15C , which are simplified sectional view illustrations of AIDAHVM  100  as shown in  FIG. 15A . 
     Following the removal of the RNS  702  from the AIDAHVM  100 , needle shield  400  is axially rearwardly displaced relative to front housing  300 , typically by the user pushing AIDAHVM  100  forwardly against an injection site. The axial rearward movement of needle shield  400  compresses spring  402  until rearward end  410  of needle shield  400  abuts forward facing annular edge surface  1014  of rear housing  1000 . Axial rearward movement of needle shield  400  causes internally extending protrusions  324  of arms  322  of front housing  300  to slide into recessed portions  422  of the needle shield  400 . Further axial rearward movement of needle shield relative to front housing  300  causes internally extending protrusions  324  of arms  322  to slide out of recessed portions  422  of needle shield  400  and to be pushed radially outwardly by outer surface of forward portion  412  of needle shield  400 . 
     Following the rearward movement of the needle shield  400 , the apertures  436  of the tabs  434  of the needle shield  400  are positioned in front of spaced radially outward protrusions  1038  of rear housing  1000  and in front of the rearward apertures  344  of front housing  300 . In this orientation, spaced radially outward protrusions  1038  are no longer supported by inner surface  435  of tabs  434  of the needle shield  400 . 
     Reference is now made to  FIG. 16A , which is a simplified pictorial view illustration of AIDAHVM  100  in a third operative orientation, which is an activation orientation, and to  FIGS. 16B-16D  which are, respectively, a simplified top view illustration and simplified sectional view illustrations of AIDAHVM  100  as shown in  FIG. 16A . 
     As seen in  FIGS. 16A-16D , following rearward displacement of needle shield  400 , AIDAHVM  100  is activated by forwardly displacing trigger button, typically by a user pushing closed rearward end  1208  of trigger button  1200 . Forward displacement of trigger button  1200  causes longitudinal resilient projections  1214  of trigger button  1200  to slide over inclined surface  949  of control unit  900  and radially outwardly, thereby pushing resilient arms  1030  of rear housing  1000  radially outwardly. As described hereinabove with reference to  FIGS. 15A-15C , spaced radially outward protrusions  1038  of resilient arms  1030  of rear housing  1000  are no longer supported by inner surface  435  of tabs  434  of needle shield  400 , which frees trigger button  1200  to be moved axially forwardly. As described above, this allows longitudinal resilient projections  1214  of trigger button  1200  together with resilient arms  1030  of rear housing  1000  to bend radially outwardly. This forward movement also causes disengagement of lateral extensions  1034  of diametrically opposite resilient arms  1030  of rear housing  1000  from spaced protrusions  948  of intermediate portion  932  of control unit  900 , thus freeing the control unit  900  to move axially forwardly under the urging of spring  902 . 
     Reference is now made to  FIG. 17A , which is a simplified pictorial view illustration of AIDAHVM  100  in a fourth operative orientation, which includes needle penetration, start of injection, injection and end of injection orientations, to  FIGS. 17B and 17C , which are simplified sectional view illustrations of AIDAHVM  100  as shown in  FIG. 17A  in a needle penetration operative orientation,  FIGS. 18A and 18B , which are simplified sectional view illustrations of AIDAHVM  100  as shown in  FIG. 17A  in a start of injection operative orientation,  FIGS. 19A-19C , which are, respectively, a simplified, partially cut away, front view illustration and simplified sectional view illustrations of AIDAHVM  100  as shown in  FIG. 17A  in an injection operative orientation, and to  FIGS. 20A-20C , which are, respectively, a simplified, partially cut away, front view illustration and simplified sectional view illustrations of AIDAHVM  100  as shown in  FIG. 17A  in an end of injection operative orientation. 
     Referring now specifically to  FIGS. 17A-17C , under the urging of spring  902 , control unit  900  moves axially forwardly and forwardly displaces syringe sleeve  600  together with syringe  700 . Needle  707  passes through opening  420  of needle shield  400  and penetrates the skin of the user, preferably achieving a desired penetration depth for administering the medication. Forward displacement of control unit  900  and syringe sleeve  600  under urging of spring  902  continues until inner forwardly facing surface  638  of syringe sleeve  600  abuts the rearward end  508  of the fixed sleeve  500 . The forward displacement of control unit  900  positions external protrusions  924  of forward resilient arms  912  of control unit  900  within longitudinal indication openings  426  of needle shield  400  and forward apertures  340  of the front housing  300 , thereby allowing forward resilient arms  912  of control unit  900  to bend radially outwardly. 
     Forward displacement of control unit  900  also causes inwardly radially extending protrusions  942  of resilient arms  930  of control unit  900  to forwardly displace rearward facing edge  1118  of forward broadened section  1116  of the RDE  1100  forwardly, thereby stretching RDE  1100 . 
     Intermediate dampening portion  1104 , which is the weakest portion of RDE  1100  is stretched at a force that is less than the axial force of spring  902 . Intermediate dampening portion  1104  thereby absorbs a portion of the axial force of spring  902  during its elongation and provides for the dampening of the movement of control unit  900 . 
     It is appreciated that in the orientation shown in  FIGS. 17A-17C , plunger rod  800  is not yet in engagement with piston  708  of syringe  700 . 
     Referring now specifically to  FIGS. 18A-18B , under the further urging of spring  902 , forward resilient arms  912  of the control unit  900  bend radially outwardly as control unit  900  is further displaced axially forwardly. The axial forward movement of control unit  900  causes radially inwardly extending protrusions  920  of forward resilient arms  912  to slide out of recesses  648  and forwardly along the outer surface  644  of rearward resilient arm  640  of syringe sleeve  600 . The external protrusions  924  of the forward resilient arms  912  of the control unit  900  are positioned below of the indication openings  426  of the needle shield  400  and forward apertures  340  of front housing  300 . 
     As seen in  FIGS. 18A and 18B , further forward movement of the control unit  900  causes forward end  804  of plunger rod  800  to engage rearward end of piston  708  of syringe  700 . 
     Upon engagement on the plunger rod  800  and piston  708 , the hydraulic resistance of the medication within syringe  700  while flowing through needle  707  slows the forward axial movement of plunger rod  800  during further forward axial movement of control unit  900 . Under the urging of the spring  902 , the control unit  900  continues to move axially forward relative to plunger rod  800 . Forward axial movement of control unit  900  relative to plunger rod  800  continues until rearward edge  811  of plunger rod  800  reaches forward facing shoulders  950  of rearward body portion  906  of control unit  900 . 
     Forward axial movement of control unit  900  relative to plunger rod  800  causes forward broadened section  1116  of RDE  1100  to enter into recess  814  of substantially hollow rear portion  810  of plunger rod  800 , thus preventing radial movement of forward broadened section  1116  of RDE  1100 . 
     Forward axial movement of control unit  900  relative to plunger rod  800  also causes protrusions  818  of plunger rod  800  to push against inclined surfaces  936  of resilient arms  930 , thus outwardly radially bending resilient arms  930  of control unit  900  and disengaging inwardly radially extending protrusions  942  of resilient arms  930  from rearward facing edge  1118  of RDE  1100 , causing the application of the entire axial force of spring  902  to the forward movement of the plunger rod  800  against piston  708  of syringe  700 . Thus, responsive to driving engagement of the at least one spring drive assembly, including spring  902 , with control unit  900 , plunger rod  800  and piston  708  the force limiting effect of at least one selectably operable spring energy output force limiter, RDE  1100 , is automatically disabled. 
     Following further forward movement of control unit  900  under the continued urging of spring  902 , longitudinal resilient projections  1214  of trigger button  1200  are no longer supported by inclined surface  949  of control unit  900  and bend radially inwardly to their original position together with resilient arms  1030  of rear housing  1000 . 
     As seen in  FIGS. 18A and 18B , spaced radially outward protrusions  1038  of resilient arms  1030  of rear housing  1000  are positioned neither within apertures  436  of tabs  434  of needle shield  400  nor within rearward apertures  344  of front housing  300 . 
     The dampening of the axial force of spring  902  by means of RDE  1100  substantially decreases the axial force that is applied to syringe  700 , and thereby reduces the probability of breakage of the syringe  700 . The dampening also reduces the noise created at the end of the syringe  700  movement and at the engagement of the plunger rod  800  with piston  708  of the syringe  700 . 
     The resilient ring  706  positioned on flange  704  of syringe  700  provides for even stress distribution over flange  704  of syringe  700 , thus also reducing the probability of breakage of the syringe  700  and also decreasing the noise level. 
     It is appreciated that the axial force of the spring  902  and the cross-sectional area of RDE  1100  may be selected based on the medication being administered and the hydraulic force created thereby, thus providing a range of injector forces without compromising the forces applied during injection. 
     Referring now specifically to  FIGS. 19A-19C , further forward axial movement of control unit  900 , under urging of spring  902 , produces forward axial movement of plunger rod  800  and piston  708  of syringe  700 . Forward axial movement of control unit  900 , plunger rod  800  and piston  708  continues as the medication in syringe  700  is injected forwardly into the injection site. As the forward movement continues lateral protrusions  922  of forward resilient arms  912  of control unit  900  bend radially outwardly above inclined edge  620  of the syringe sleeve  600  and further slide over protrusions  542  of forward cylindrical portion  510  of fixed sleeve  500 . 
     Referring now specifically to  FIGS. 20A-20C , following the completion of the injection piston  708  of syringe  700  is disposed at the forward end of syringe  700  and forward resilient arms  912  of the control unit  900  create an audible signal that indicates end of injection as lateral protrusions  922  of the forward resilient arms  912  of the control unit  900  disengage from protrusions  542  of forward cylindrical portion  510  of fixed sleeve  500 . 
     Reference is now made to  FIG. 21A , which is a simplified pictorial view illustration of AIDAHVM  100  in a discard orientation, and to  FIGS. 21B-21C  which are simplified sectional view illustrations of AIDAHVM  100  as shown in  FIG. 21A . 
     Following the end of the injection of the medication in syringe  700 , the user removes AIDAHVM  100  from the injection site. As the AIDAHVM  100  is removed, needle shield  400  moves axially forward relative to front housing  300  under the urging of spring  402  and covers needle  707  of syringe  700 . The forward axial movement of needle shield  400  relative to front housing  300  continues until rearward edge  425  of longitudinal openings  424  of needle shield  400  engages extending protrusions  632  of forward resilient arms  622  of syringe sleeve  600 . 
     As seen in  FIGS. 21A-21C , internally extending protrusions  324  of resilient arms  322  of the front housing  300  slide into longitudinal indication opening  426  of the needle shield  400  adjacent its forward edge, as resilient arms  322  of front housing  300  returns to their original position. 
     In the discard orientation shown in  FIGS. 21A-21C , needle  707  of syringe  700  is shielded by needle shield  400 . Attempted retraction of needle shield  400  into front housing  300  by rearward axial displacement of needle shield  400  relative to front housing  300  is prevented, thereby preventing exposure of needle  707  of syringe  700 , by location of forward edge of longitudinal indication opening  426  of needle shield  400  forward of forward facing edge  328  of the resilient arms  322  of the front housing  300 . 
     It is appreciated that the term “at a radial distance of generally 90°” as used throughout the description of the present invention refers to a radial distance of 90°±5°. 
     It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and sub-combinations of various features described hereinabove as well as variations and modifications thereof which are not in the prior art.