Abstract:
A needle tip assembly includes a needle tip, a needle tip cover structured and arranged to facilitate installation of the needle tip onto at least one of a pen needle, a pre-loaded syringe, and an injection device, and a slot arranged on a sidewall of a body of the needle tip. 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:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. application Ser. No. 12/963,678 filed Dec. 9, 2010, which application is a continuation of U.S. application Ser. No. 11/616,195 filed Dec. 26, 2006. The disclosure of each of these applications is/are expressly incorporated by reference herein in its/their entireties. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to pen needles, e.g., pre-loaded syringes, such are utilized for injection of medicament into the body tissues of human and animal patients. More specifically, this invention relates to a pen needle having a removable tip which can be prevented from reuse and/or which utilizes one or more mechanisms for preventing the possibility of inadvertent needle pricks. 
     This invention also relates to pen needle tips for pen needles wherein the pen needle tip is configured to prevent it from being re-used. 
     This invention also relates to tips for devices such as, e.g., pre-loaded syringes, which can be used only once, i.e., single-use tips, and/or to tips which include one or more mechanisms for preventing the user from being pricked when handling the tip. 
     2. Discussion of Background Information 
     U.S. Pat. No. 4,973,318, the disclosure of which is hereby expressly incorporated by reference in its entirety, discloses a disposable syringe includes first and second housing elements which are coupled together for rotation without axial movement therebetween. The first housing element receives a cartridge of a solution to be injected, and mounts a liquid outlet needle at its front end. A piston rod is disposed in the second housing element to move axially therein, and this piston rod includes a rod element and a nut element. The rod element is coupled to the first housing element to move axially therein without relative rotation therewith, and the nut element is threaded to the rod element for telescoping movement therewith and is configured to move axially in the second housing element without relative rotation therein. A pressure receiving element is mounted on the nut element. The housing, rod, nut and pressure receiving elements cooperate such that relative rotation between the housing elements in a selected direction causes relative rotation between the nut and rod elements and thereby increases the effective length of the piston rod and causes the pressure receiving element to extend from the second housing element. A protective cap is removably mounted over the first housing element and is configured to abut second housing element while mounted in place on the first housing element. This protective cap is engaged with the first housing element such that rotation of the cap with respect to the second housing element causes rotation of the first housing element with respect to the second housing element. 
     This type of syringe is shown in  FIGS. 1-7  wherein the pre-loaded syringe  1  has a proximal threaded end  2  which is configured to accept a needle tip assembly consisting of a needle tip  5 , a needle tip cover  3 , and a needle cover  4 . As is evident from  FIGS. 2 and 3 , a user installs the needle tip assembly  3 / 4 / 5 , after removing the assembly from its individual package, onto the threaded proximal end  2  by simply sliding it onto the end  2  axially. Because internal threads of the needle tip  5  are mounted to radially deflectable members, installation over threads of the end  2  occurs with a ratchet effect. This installation is made safe by the covers  4  and  5  which ensure that the user will not be pricked by the needle N. Once installed, the user can remove the needle tip cover  3  by simply sliding it off axially as is shown in  FIG. 4 . Next, as shown in  FIG. 5 , the user can remove the needle cover  4  to expose the needle N. The pen needle device then assumes the position shown in  FIG. 6  and is made ready for use in providing an injection to the user. After injection, the user will typically remove the needle tip  5  and discard the same. To accomplish the removal, the user will typically reinstall the needle tip cover  3  and rotate it to cause the needle tip to unthread from the threaded end  2  (some users may even install the needle cover  4  prior to installing the cover  3 ). Once removed, however, it is still possible to reinstall the used needle tip  5  by simply repeating the steps noted above.  FIG. 7  illustrates that the needle tip  5  can even be installed without the needle covers  3  and  4 . Unless the user discards the needle tip  5 , it is possible that she or other users will not remember or know that it has already been used. That is, there is nothing to prevent reuse of the needle tip  5  should someone attempt to reinstall the needle tip onto the end  2 . Furthermore, if the user is unable to locate the covers  3  and  4  (i.e., if they have become lost), she must then attempt to grip the needle tip  5  in order to unthread it from the end  2 . As is apparent, this action can be risky because the user can possibly inadvertently be pricked by the needle N either in attempting to properly grip the needle tip  5 , in the action of rotating it to the point it is removed, or even in the handling of the needle tip  5  after it has been removed and prior to being properly discarded. Still further, if the needle tip  5  is not properly discarded (such as being correctly placed in a sharps container), others may come in contact with the needle tip  5  and possibly become injured thereby. 
     It is therefore desirable to provide a pen needle system which is safer to use compared to the conventional devices discussed above and/or which does not have one or more of the above-noted disadvantageous. 
     SUMMARY OF THE INVENTION 
     According to one non-limiting embodiment of the invention, there is provided a pen needle having a removable tip which can be prevented from reuse and/or which utilizes one or more mechanisms for preventing the possibility of inadvertent needle pricks. 
     According to another non-limiting embodiment of the invention, there is provided a pen needle tip for a pen needle wherein the pen needle tip is configured to prevent it from being re-used. 
     According to another non-limiting embodiment of the invention, there is provided a needle tip for a device such as, e.g., a pre-loaded syringe, which can be used only once, i.e., single-use tips, and/or to tips which include one or more mechanisms for preventing the user from being pricked when handling the tip. 
     According to another non-limiting embodiment of the invention, there is provided a pre-loaded syringe or pen needle injection device tip assembly comprising a needle tip comprising a body and a needle having a first puncturing end projecting out beyond a forward end of the body and a second puncturing end projecting into an interior space of the body. The interior space of the body is sized and configured to receive therein one end of the pre-loaded syringe or the pen needle injection device. A generally cylindrical sidewall of the body includes a slot oriented parallel to the needle. The second puncturing end being sized and configured to extend into the one end when the body is installed on the one end. The needle tip is structured and arranged to be removably connected to the one end of the pre-loaded syringe or the pen needle injection device. 
     According to another non-limiting embodiment of the invention, there is provided a needle tip assembly comprising a needle tip, a needle tip cover structured and arranged to facilitate installation of the needle tip onto at least one of a pen needle, a pre-loaded syringe, and an injection device, and at least one of an arrangement for preventing re-installation or re-use of the needle tip, a safety mechanism coupled to the needle tip via a living hinge, and a safety cover non-removably coupled to the needle tip. 
     The arrangement may comprise a ring which is from a first position to a second position. The arrangement may comprise a ring which is axially moveable. The arrangement may comprise a locking member which is from an unlocked position to a locked position. The arrangement may comprise a movable member mounted to a body of the needle tip, wherein the movable member is axially moveable from a first position to a second position by the needle tip cover. The arrangement may comprise a movable member mounted to a body of the needle tip, wherein the movable member is axially moveable from a first position to a second position, and wherein, when in the second position, the needle tip is prevented from being re-installed. The arrangement may comprise an elastic member mounted to a body of the needle tip, wherein the elastic member is moveable from a first position to a second position, and wherein, when in the second position, the needle tip is prevented from being re-installed. The arrangement may comprise at least one inwardly projecting member adapted to be deflected inwardly. The at least one inwardly projecting member may be biased away from inward deflection. The arrangement may further comprise a ring which is moveable from a first position to a second position causing inward deflection of the at least one inwardly projecting member. The arrangement may further comprise a ring which is axially moveable to a position causing inward deflection of the at least one inwardly projecting member. The arrangement may further comprise a locking member which is moveable from an unlocked position to a locked position causing inward deflection of the at least one inwardly projecting member. The arrangement may further comprise a movable member mounted to a body of the needle tip, wherein the movable member is axially moveable from a first position to a second position by the needle tip cover, whereby the second position causes inward deflection of the at least one inwardly projecting member. The arrangement may further comprise a movable member mounted to a body of the needle tip, wherein the movable member is axially moveable from a first position to a second position, and wherein, when in the second position, the needle tip is prevented from being re-installed by inward deflection of the at least one inwardly projecting member. The arrangement may further comprise an elastic member mounted to a body of the needle tip, wherein the elastic member is moveable from a first position to a second position, and wherein, when in the second position, the needle tip is prevented from being re-installed by inward deflection of the at least one inwardly projecting member. The safety mechanism may comprise a proximal needle cover. The safety mechanism may comprise a member which covers a distal end of the needle tip. The safety cover may comprise a proximal needle cover. The safety cover may comprise a member which covers a distal end of the needle tip. The needle tip cover may be structured and arranged to facilitate removal of the needle tip from the at least one of the pen needle, the pre-loaded syringe, and the injection device. 
     According to another non-limiting embodiment of the invention, there is provided a needle tip assembly comprising a needle tip comprising a body and a needle projecting from the body and a needle tip cover structured and arranged to facilitate installation of the needle tip onto at least one of a pen needle, a pre-loaded syringe, and an injection device, wherein the needle tip cover activates an arrangement for preventing re-installation or re-use of the needle tip. 
     The assembly may further comprise at least one of a safety mechanism coupled to the needle tip via a living hinge and a safety cover non-removably coupled to the needle tip. The needle tip cover may be structured and arranged to facilitate removal of the needle tip from the at least one of the pen needle, the pre-loaded syringe, and the injection device, 
     According to another non-limiting embodiment of the invention, there is provided a needle tip assembly comprising a needle tip comprising a body, a needle projecting from the body, and at least one inwardly projecting member adapted to be deflected inwardly and a needle tip cover structured and arranged to facilitate installation of the needle tip onto at least one of a pen needle, a pre-loaded syringe, and an injection device, wherein, when the at least one inwardly projecting member is deflected inwardly, the needle tip is prevented from being re-installed. 
     The needle tip cover may activate an arrangement for preventing re-installation or re-use of the needle tip. The assembly may further comprise at least one of a safety mechanism coupled to the needle tip via a living hinge and a safety cover non-removably coupled to the needle tip. The needle tip cover may be structured and arranged to facilitate removal of the needle tip from the at least one of the pen needle, the pre-loaded syringe, and the injection device. The assembly may further comprise an arrangement that is moveable from a first position to a second position. The arrangement may comprise a ring which is axially moveable. The arrangement may comprise a locking member which is moveable from an unlocked position to a locked position. The arrangement may comprise a movable member mounted to the body of the needle tip, wherein the movable member is axially moveable from a first position to a second position by the needle tip cover. The arrangement may comprise a movable member mounted to the body of the needle tip, wherein the movable member is axially moveable from a first position to a second position, and wherein, when in the second position, the needle tip is prevented from being re-installed. The arrangement may comprise an elastic member mounted to the body of the needle tip, wherein the elastic member is moveable from a first position to a second position, and wherein, when in the second position, the needle tip is prevented from being re-installed. 
     According to another non-limiting embodiment of the invention, there is provided a method of using the needle tip assembly of the type described above, wherein the method comprises installing the needle tip assembly onto a proximal end of an injection device, activating the arrangement before using the injection device, and re-installing the needle tip cover and removing the needle tip using the needle tip cover. 
     According to another non-limiting embodiment of the invention, there is provided a method of using the needle tip assembly of the type described above, wherein the method comprises installing the needle tip assembly onto a proximal end of an injection device, activating with the needle tip cover, an arrangement for preventing re-installation or re-use of the needle tip, and re-installing the needle tip cover and removing the needle tip using the needle tip cover. 
     According to another non-limiting embodiment of the invention, there is provided a method of using the needle tip assembly of the type described above, wherein the method comprises installing the needle tip assembly onto a proximal end of an injection device and re-installing the needle tip cover and removing the needle tip using the needle tip cover, wherein after removal, the at least one inwardly projecting member is deflected inwardly so as to prevent re-installation of the needle tip. 
     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 
       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: 
         FIG. 1  shows an enlarged partial side view of a proximal end of a prior art pen needle or pre-loaded syringe/injection device. The proximal end is shown with the cap removed and in a prior-use state, i.e., it is ready to receive thereon a needle tip; 
         FIG. 2  shows the proximal end of  FIG. 1  along with a prior art needle tip assembly in a position prior to installation onto the proximal end. The needle tip cap and the needle cap are both shown in cross-section; 
         FIG. 3  shows the proximal end and prior art needle tip assembly of  FIG. 2  after installation of the needle tip assembly onto the proximal end; 
         FIG. 4  shows how the needle tip cap can be removed from the prior art needle tip assembly of  FIG. 3 ; 
         FIG. 5  shows how the needle cap can be removed from the prior art needle tip of  FIG. 4 ; 
         FIG. 6  shows the needle tip mounted onto the pen needle device in a position ready for injection according to the prior art; 
         FIG. 7  shows the needle tip being removed from the pen needle device according to the prior art. This would occur after use and can occur by unthreading the needle tip from the threaded proximal end of the pen needle device. The arrow illustrates that it is possible to re-install the needle tip onto the threaded proximal end of the pen needle device; 
         FIG. 8  shows the proximal end of  FIG. 1  along with a needle tip assembly according to one embodiment of the invention. The needle tip assembly is shown in a position prior to installation onto the proximal end. The needle tip is shown in partial cross-section while the needle tip cap and the needle cap are shown in cross-section; 
         FIG. 9  shows the needle tip assembly of  FIG. 8  after installation onto the proximal end; 
         FIG. 10  shows the needle tip assembly of  FIG. 9  after the needle tip cap is moved axially to a position which causes a ring to move to a locked position; 
         FIG. 11  shows the needle tip assembly of  FIG. 10  as the needle tip cap is removed; 
         FIG. 12  shows the needle tip assembly of  FIG. 11  as the needle cap is removed; 
         FIG. 13  shows the pen needle device with the installed needle tip of  FIG. 12  in a position that is ready for injection. In this position, the ring has been moved to the locked position which has caused a plurality of inwardly deflecting members to engage the threaded proximal end of the pen needle device; 
         FIG. 14  shows the needle tip and proximal end of  FIG. 13  after or as the needle tip is removed from the proximal end. As is evident from  FIG. 14 , because the ring has been moved to the locked position and caused a plurality of inwardly deflecting members to engage the threaded proximal end of the pen needle device, when the needle tip is removed, these inwardly deflecting members move inwardly to the point wherein they will interfere with and/or prevent re-installation of the needle tip; 
         FIG. 15  shows how the inwardly deflecting members interfere with and/or prevent re-installation of the needle tip, i.e., the inwardly oriented projections do not threadably engage with the threads of the proximal end and function to, in effect, reduce a diameter of the distal opening of the needle tip to the point that it is smaller than the outer diameter of the proximal end; 
         FIG. 16  shows a distal end view of the needle cap which can be used in the needle tip assembly according to the invention; 
         FIG. 17  shows a side cross-section view of the needle cap of  FIG. 16 ; 
         FIG. 18  shows a distal end view of the needle tip cap which can be used in the needle tip assembly according to the invention; 
         FIG. 19  shows a side cross-section view of the needle tip cap of  FIG. 18 ; 
         FIG. 20  shows the proximal end of  FIG. 1  along with a needle tip assembly according to another embodiment of the invention. The needle tip assembly is shown in a position prior to installation onto the proximal end. The needle tip is shown in partial cross-section while the needle tip cap and the needle cap are shown in cross-section; 
         FIG. 21  shows the needle tip assembly of  FIG. 20  after installation onto the proximal end; 
         FIG. 22  shows the needle tip assembly of  FIG. 21  after the needle tip cap is moved axially to a position which causes a ring to move to a locked position; 
         FIG. 23  shows the needle tip assembly of  FIG. 22  as the needle tip cap is removed; 
         FIG. 24  shows the needle tip assembly of  FIG. 23  as the needle cap is removed; 
         FIG. 25  shows the pen needle device with the installed needle tip of  FIG. 24  in a position that is ready for injection. In this position, the ring has been moved to the locked position which has caused a plurality of inwardly deflecting members to engage the threaded proximal end of the pen needle device; 
         FIG. 26  shows the needle tip and proximal end of  FIG. 25  as the needle tip is removed from the proximal end. Unlike the previous embodiment which utilizes internal threads arranged within the needle tip to threadably engage with the treads of the proximal end of the pen needle device, this embodiment relies upon a threaded engagement between the inwardly projecting members and the threaded proximal end of the pen needle device for removal of the needle tip. As is evident from  FIG. 26 , because the ring has been moved to the locked position and caused a plurality of inwardly deflecting members to engage the threaded proximal end of the pen needle device, when the needle tip is removed, these inwardly deflecting members move inwardly to the point wherein they will interfere with and/or prevent re-installation of the needle tip; 
         FIG. 27  shows the needle tip and proximal end of  FIG. 26  after the needle tip is removed from the proximal end; 
         FIG. 28  shows how the inwardly deflecting members interfere with and/or prevent re-installation of the needle tip, i.e., the inwardly oriented projections have deflected inwardly to the point that they can no longer threadably engage with the threads of the proximal end and function to, in effect, reduce a diameter of the distal opening of the needle tip to the point that it is smaller than the outer diameter of the proximal end; 
         FIG. 29  shows a distal end of another needle tip which can be used in the embodiment of  FIGS. 20-28 . The lock ring has been removed for purposes of clarity. Unlike the embodiment of  FIGS. 20-28  which utilizes two oppositely arranged inwardly deflecting members, this embodiment utilizes four equally spaced inwardly projecting members. As is evident from  FIG. 29 , the inwardly oriented projections have deflected inwardly to the point that they, in effect, reduce a diameter of the distal opening of the needle tip so that it is smaller than the outer diameter of the proximal end; 
         FIG. 30  shows a side partial cross-section view of the needle tip of  FIG. 29 ; 
         FIG. 31  shows a cross-section view of the ring which can be used in the embodiments shown in  FIGS. 8-30 ; 
         FIG. 32  shows a distal end view of the ring of  FIG. 31 ; 
         FIG. 33  shows a needle tip assembly according to still another embodiment of the invention. The needle tip assembly is shown in a position prior to installation onto the proximal end. The needle tip is shown in partial cross-section while the needle tip cap and the needle cap are shown in cross-section. Unlike the previous embodiments shown in  FIGS. 8-32 , this embodiment utilizes a ring which does not lock when moved to a position causing the inwardly projecting members to deflect inwardly. As such, the needle tip does not include projections which would engage with a recess in the ring; 
         FIG. 34  shows a needle tip assembly according to still another embodiment of the invention. The needle tip assembly is shown in a position prior to installation onto the proximal end. The needle tip is shown in partial cross-section while the needle tip cap and the needle cap are shown in cross-section. Unlike the previous embodiments shown in  FIGS. 8-32 , this embodiment utilizes a ring which does not lock when moved to a position causing the inwardly projecting members to deflect inwardly; 
         FIG. 35  shows a needle tip assembly according to still another embodiment of the invention. The needle tip assembly is shown in a position prior to installation onto the proximal end. The needle tip is shown in partial cross-section while the needle tip cap and the needle cap are shown in cross-section. Unlike the previous embodiments shown in  FIGS. 8-32 , this embodiment utilizes a ring which does not have a tapered distal end and does not lock to the needle tip when moved to a position causing the inwardly projecting members to deflect inwardly; 
         FIG. 36  shows a side view of a needle tip according to still another embodiment of the invention. The needle tip is shown in a position prior to installation onto the proximal end. Unlike the previous embodiments shown in  FIGS. 8-32 , this embodiment utilizes an elastic ring and a slotted distal end portion on the needle tip. That way, when the ring is moved towards the distal end, the ring causes the slotted distal end to compress or deflect inwardly; 
         FIG. 37  shows a distal end view of a needle tip shown in  FIG. 36 ; 
         FIG. 38  shows a side view of a needle tip of  FIG. 36  with the needle tip being in a position after removal from the proximal end. The ring has been moved towards the distal end causing the slotted distal end of the needle tip to compress or deflect inwardly and thereby prevent its re-installation; 
         FIG. 39  shows a side view of a needle tip according to still another embodiment of the invention. The needle tip is similar to that shown in the embodiment of  FIGS. 8-19  except that it utilizes mechanisms for transferring torque from the needle tip cap to the needle tip. These mechanisms have the form of projections formed on the needle tip which slidably engage with recesses formed within the needle tip cap; 
         FIG. 40  shows a side cross-section view of a needle tip cap which can be used with the needle tip shown in  FIG. 39 . The needle tip cap is similar to that shown in the embodiment of  FIGS. 8-19  except that it utilizes mechanisms for transferring torque from the needle tip cap to the needle tip. These mechanisms have the form of recesses formed within the needle tip cap which slidably receive therein the projections formed on the needle tip; 
         FIG. 41  shows a needle tip assembly according to still another embodiment of the invention. The needle tip assembly is shown in a position after being installed onto the proximal end of the pen needle injection device. The needle tip is shown in partial cross-section while the needle tip cap and the needle cap are shown in cross-section. Unlike the previous embodiments shown in  FIGS. 8-40 , this embodiment utilizes a needle tip cap that is slid over the proximal end of the pen needle device and remains on the device during injection. Furthermore, the ring includes a circumferential projection which acts to retain the needle tip cap in the position shown in  FIG. 41 ; 
         FIG. 42  shows the needle tip assembly of  FIG. 41  after the needle tip cap is slid back to activate or move the ring to the locking position and also expose the needle and needle cap; 
         FIG. 43  shows the needle tip assembly of  FIG. 42  after the needle cap is removed. As is shown in  FIG. 43 , the needle is now exposed and the pen needle device can now be used for injection; 
         FIG. 44  shows the needle tip assembly of  FIG. 43  after the needle tip cap is moved back to the original position shown in  FIG. 41 . As is shown in  FIG. 44 , the needle is now covered or protected by the needle tip cap; 
         FIG. 45  shows a needle tip assembly according to still another embodiment of the invention. The needle tip assembly is shown in a position after being installed onto the proximal end of the pen needle injection device. The needle tip is shown in partial cross-section while the needle tip cap and the needle cap are shown in cross-section. This embodiment is similar to the embodiment shown in  FIGS. 41-44  except that it also includes a spring which biases the needle tip cap towards the original position; 
         FIG. 46  shows the pen needle device with a installed needle tip according to another non-limiting embodiment of the invention. This embodiment utilizes a ring which frictionally engages with projections of the needle tip without locking with the projections. In this position, the ring has been moved to the locked position which has caused a plurality of inwardly deflecting members to engage the threaded proximal end of the pen needle device; 
         FIG. 47  shows a distal end view of another embodiment of a needle tip cap which can be used with one or more of the needle tip assembly embodiments. The needle tip cap is of a two-piece construction which pieces are connected one side with a living hinge and on the other side with a snap-together lock system; 
         FIG. 48  shows a side cross-section view of the needle tip cap shown in  FIG. 47 ; 
         FIG. 49  shows another distal end view of the needle tip cap shown in  FIG. 47  except that the two-piece construction is shown in the open position; 
         FIG. 50  shows the proximal end of  FIG. 1  along with a needle tip assembly according to another embodiment of the invention. The needle tip assembly is similar to that shown in the prior art  FIGS. 1-7  except that the needle tip includes a rear cap member which is mounted to the needle tip body via a living hinge. The needle tip cap also includes a mechanism which allows the rear cap member to temporarily lock thereto. The rear cap, needle tip cap and the needle cap are shown in cross-section; 
         FIG. 51  shows the needle tip assembly of  FIG. 50  after the rear end cap is unlocked from the needle tip cap and been deflected distally. In this position, the needle tip cap can then be removed in the manner shown in  FIG. 4 ; 
         FIG. 52  shows the needle tip used in the embodiment shown in  FIG. 50  and illustrates how the rear cap can be deflected via the living hinge to a position prior to covering the distal end of the needle tip; 
         FIG. 53  shows the proximal end of  FIG. 1  along with a needle tip assembly according to another embodiment of the invention. The needle tip is similar to that shown in the prior art  FIGS. 1-7  except that the needle tip includes a needle cap member which is mounted to the needle tip body via a living hinge. The needle cap also includes a mechanism which allows the needle cap member to temporarily lock to the needle tip body. The needle cap is shown in cross-section; 
         FIG. 54  shows the needle tip assembly of  FIG. 53  after the needle cap is unlocked from the needle tip and been deflected distally. In this position, the needle tip can be used to perform an injection; 
         FIG. 55  shows one non-limiting way in which a plurality of needle tip assemblies of either the prior art variety or those of the invention described herein can be packaged in a housing. The housing also functions as a tool for installing one needle tip assembly at a time onto the end of a pen needle; 
         FIG. 56  shows the housing after one of the needle tip assemblies has been installed onto the end of a pen needle; and 
         FIG. 57  shows the housing after the user advances a push-button to move the needle tip assemblies to a position that readies it for installing another of the needle tip assemblies onto the end of a pen needle. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings and first to  FIGS. 8-19  which shows a first embodiment of a needle tip assembly. The needle tip assembly includes a needle tip cap  30  having various generally cylindrical portions with different diameters, a needle cap  40 , and a needle tip  50 . The proximal end  30   a  of the needle tip cap  30  is closed while the distal end includes a circumferential flange  30   b . The proximal end  40   a  of the needle cap  40  is closed while the distal end includes a circumferential flange  40   b . The proximal end of the needle tip  50  includes a needle N while the distal end includes an opening which is sized to allow the needle tip  50  to be mounted to the threaded proximal end  2  of the pen needle device  1 . In order to ensure that the needle tip  50  is prevented from being re-installed onto the proximal end  2 , the needle tip  50  utilizes a ring  60  which can move axially from an initial position (see  FIG. 9 ) to a second position (see  FIG. 10 ) which causes one or more inwardly deflecting members  50   a  and  50   b  to deflect inwards by an amount which is sufficient to prevent the needle tip  50  (after being removed) from being re-installed onto the proximal end  2 . As can be seen in  FIG. 8 , prior the needle tip assembly being installed onto the threaded proximal end  2 , the one or more inwardly deflecting members  50   a  and  50   b  are bent outwardly or deflected outwardly by an amount which is sufficient to allow the needle tip  50  to be installed onto the proximal end  2  in the conventional manner, i.e., by axially sliding it on or by threading it on. 
     As can be seen in  FIG. 9 , the needle tip assembly can be installed onto the threaded proximal end  2  without activating the re-use prevention mechanism, i.e., without causing the ring  60  to move axially to the locked position. Accordingly, in the position shown in  FIG. 9 , the one or more inwardly deflecting members  50   a  and  50   b  are still bent outwardly or deflected outwardly by an amount which is sufficient to allow the needle tip  50  to be installed onto the proximal end  2  in the conventional manner. Furthermore, while the ring  60  is in the position shown in  FIG. 9 , the needle tip assembly can be removed in the conventional way by, e.g., unthreading it off of the threaded end  2 . 
     As can be seen in  FIG. 10 , after the needle tip assembly is installed onto the threaded proximal end  2  (as shown in  FIG. 9 ), the needle tip cap  30  can be further moved axially in the distal direction (as indicated by the arrow in  FIG. 10 ) to the point that it activates the re-use prevention system or mechanism, i.e., it causes the ring  60  to move axially in the distal direction until it assumes the locked position. The locked position is characterized by engagement between the projections of the one or more inwardly deflecting members  50   a  and  50   b  and the inner circumferential recess of the ring  60 . Accordingly, in the position shown in  FIG. 10 , the one or more inwardly deflecting members  50   a  and  50   b  have been deflected inwardly so that they are now biased against the proximal end  2  and frictionally engage the threads thereof when the needle tip  50  is unthreaded. Furthermore, while the ring  60  is in the position shown in  FIG. 10 , the needle tip assembly can be removed, e.g., in the conventional way by unthreading it off of the threaded end  2 , but, unlike the prior art, cannot thereafter be reinstalled. 
     As can be seen in  FIG. 11 , once the needle tip assembly is installed ( FIG. 9 ) and the re-use prevention system activated ( FIG. 10 ), the needle tip cap  30  can be removed by sliding it off axially. Then, as shown in  FIG. 12 , the needle cap  40  can be removed.  FIG. 13  shows the pen needle device with the installed needle tip  50  in a position that is ready for injection. Again, in this position, the ring  60  has been moved to the locked position which has caused a plurality of inwardly deflecting members  50   a  and  50   b  to frictionally engage the threaded proximal end  2  of the pen needle device  1 . 
     As can be seen in  FIG. 14 , once the pen needle device with the installed needle tip assembly has been used to perform an injection, the needle tip  50  can be removed in the following ways: one could simply grip the needle tip  50  in the area of the ring  60  and unthread it from the threaded proximal end  2 . This is risky, of course, because the user can be inadvertently be pricked by the exposed needle N; one could re-install the needle cap  40  and then grip the needle tip  50  in the area of the ring  60  and unthread it from the threaded proximal end  2 ; one could re-install both the needle cap  40  and the needle tip cap  30 , and then grip the needle tip cap  30  in the area just in front of the flange  30   b  and thereafter unthread the entire needle tip assembly thereby causing the needle tip  50  to become unthreaded from the threaded proximal end  2 ; and one could re-install only the needle tip cap  30 , and then grip the needle tip cap  30  in the area just in front of the flange  30   b  and thereafter unthread the needle tip assembly (without the cap  40 ) thereby causing the needle tip  50  to become unthreaded from the threaded proximal end  2 . All of these ways are contemplated by the invention, but the first way is the least desirable. 
     As is evident from  FIG. 14 , once the needle tip  50  is removed from the threaded proximal end  2  (and because the ring  60  has been moved to the locked position), the plurality of inwardly deflecting members  50   a  and  50   b  are caused to move inwardly to the point that they will not permit (i.e., they will interfere with) re-installation of the needle tip  50  back onto the threaded proximal end  2  of the pen needle device  1 . This is evident from  FIG. 15  which shows how the plurality of inwardly deflecting members  50   a  and  50   b  have been moved inwardly to the point that they will not permit (i.e., they will interfere with) re-installation of the needle tip  50  back onto the threaded proximal end  2  of the pen needle device  1  owing to the fact that they effectively reduce the diameter of the distal opening of the needle tip  50 . 
     As is evident from  FIGS. 16 and 17 , the needle cap  40  has a closed proximal end  40   a , an open distal end having a circumferential flange  40   b , a distal opening  40   c  sized to frictionally engage with a hub portion of the needle tip  50 , and a tapered portion  40   d  which is sized to safely receive therein the needle N. Of course, the needle cap  40  can have any desired configuration provided that it functions for its intended purpose, and can even be dispensed with out leaving the scope of the invention. 
     As is evident from  FIGS. 18 and 19 , the needle tip cap  30  has a closed proximal end  30   a , an open distal end having a circumferential flange  30   b , a distal opening  30   c  sized to receive therein the ring  60 , a shoulder  30   c  which engages with a distal end of the ring  60  so as to cause the ring  60  to move to the locked position, a generally circumferential surface  30   e  which is sized to frictionally engage with an outer surface of the needle tip  50  so as to cause it to rotate relative to the proximal end  2 , and a tapered and/or stepped portion  30   f  which is sized to safely receive therein the needle N and the needle cap  40 . Of course, the needle tip cap  30  can have any desired configuration provided that it functions for its intended purpose, and can even be dispensed with out leaving the scope of the invention. In the later case, only the needle cap  40  (or even one of the type shown in  FIGS. 53 and 54 ) would need to be utilized (for safety reasons) and the user could activate the re-use prevention system by gripping the ring  60  and sliding it distally until it assumes the locked position. 
       FIGS. 20-28  shows a second embodiment of a needle tip assembly. The needle tip assembly includes a needle tip cap  30  having various generally cylindrical portions with different diameters, a needle cap  40 , and a needle tip  50 ′. As the needle tip cap  30 , the needle cap  40 , and the ring  60  of the instant embodiment are essentially identical to those used in the previous embodiment, they have been accorded the same reference numerals. The proximal end  30   a  of the needle tip cap  30  is closed while the distal end includes a circumferential flange  30   b . Similarly, the proximal end  40   a  of the needle cap  40  is closed while the distal end includes a circumferential flange  40   b . The proximal end of the needle tip  50 ′ includes a needle N while the distal end includes an opening which is sized to allow the needle tip  50 ′ to be mounted to the threaded proximal end  2  of the pen needle device  1 . In order to ensure that the needle tip  50 ′ is prevented from being re-installed onto the proximal end  2 , the needle tip  50 ′ utilizes a ring  60  which can move axially from an initial position (see  FIG. 21 ) to a second position (see  FIG. 22 ) which causes one or more inwardly deflecting members  50 ′ a  and  50 ′ b  to deflect inwards by an amount which is sufficient to prevent the needle tip  50 ′ (after being removed) from being re-installed onto the proximal end  2 . As can be seen in  FIG. 20 , prior the needle tip assembly being installed onto the threaded proximal end  2 , the one or more inwardly deflecting members  50 ′ a  and  50 ′ b  are bent outwardly or deflected outwardly by an amount which is sufficient to allow the needle tip  50 ′ to be installed onto the proximal end  2  in the conventional manner, i.e., by axially sliding it on or by threading it on. 
     As can be seen in  FIG. 21 , the needle tip assembly can be installed onto the threaded proximal end  2  without activating the re-use prevention system or mechanism, i.e., without causing the ring  60  to move axially to the locked position. Accordingly, in the position shown in  FIG. 21 , the one or more inwardly deflecting members  50 ′ a  and  50 ′ b  are still bent outwardly or deflected outwardly by an amount which is sufficient to allow the needle tip  50 ′ to be installed onto the proximal end  2 . Furthermore, while the ring  60  is in the position shown in  FIG. 21 , the needle tip assembly can be removed in the conventional way, e.g., by unthreading it off of the threaded end  2 . 
     As can be seen in  FIG. 22 , after the needle tip assembly is installed onto the threaded proximal end  2  (as shown in  FIG. 21 ), the needle tip cap  30  can be further moved axially in the distal direction (as indicated by the arrow in  FIG. 22 ) to the point that it activates the re-use prevention system or mechanism, i.e., it causes the ring  60  to move axially in the distal direction until it assumes the locked position. The locked position is characterized by engagement between the projections of the one or more inwardly deflecting members  50 ′ and  50 ′ and the inner circumferential recess of the ring  60 . Accordingly, in the position shown in  FIG. 22 , the one or more inwardly deflecting members  50 ′ a  and  50 ′ b  have been deflected inwardly so that they are now biased against the proximal end  2  and frictionally engage the threads thereof when the needle tip  50 ′ is unthreaded. Furthermore, while the ring  60  is in the position shown in  FIG. 22 , the needle tip assembly can be removed, e.g., in the conventional way by unthreading it off of the threaded end  2 , but, unlike the prior art, cannot thereafter be reinstalled. 
     As can be seen in  FIG. 23 , once the needle tip assembly is installed ( FIG. 21 ) and the re-use prevention system activated ( FIG. 22 ), the needle tip cap  30  can be removed by sliding it off axially. Then, as shown in  FIG. 24 , the needle cap  40  can also be removed axially.  FIG. 25  shows the pen needle device with the installed needle tip  50 ′ in a position that is ready for injection. Again, in this position, the ring  60  has been moved to the locked position which has caused a plurality of inwardly deflecting members  50 ′ a  and  50 ′ b  to frictionally engage the threaded proximal end  2  of the pen needle device  1 . 
     As can be seen in  FIGS. 26 and 27 , once the pen needle device with the installed needle tip assembly has been used to perform an injection, the needle tip  50 ′ can be removed in the following ways: one could simply grip the needle tip  50 ′ in the area of the ring  60  and unthread it from the threaded proximal end  2 . This is risky, of course, because the user can be inadvertently be pricked by the exposed needle N; one could re-install the needle cap  40  and then grip the needle tip  50 ′ in the area of the ring  60  and unthread it from the threaded proximal end  2 ; one could re-install both the needle cap  40  and the needle tip cap  30 , and then grip the needle tip cap  30  in the area just in front of the flange  30   b  and thereafter unthread the entire needle tip assembly thereby causing the needle tip  50 ′ to become unthreaded from the threaded proximal end  2 ; and one could re-install only the needle tip cap  30 , and then grip the needle tip cap  30  in the area just in front of the flange  30   b  and thereafter unthread the needle tip assembly (without the cap  40 ) thereby causing the needle tip  50 ′ to become unthreaded from the threaded proximal end  2 . As was the case in the previous embodiment, all of these ways are contemplated by the invention for this embodiment, with, however, the first way being the least desirable. 
     As is evident from  FIG. 28 , once the needle tip  50 ′ is removed from the threaded proximal end  2  (and because the ring  60  has been moved to the locked position), the plurality of inwardly deflecting members  50 ′ a  and  50 ′ b  are caused to move inwardly to the point that they will not permit (i.e., they will interfere with) re-installation of the needle tip  50 ′ back onto the threaded proximal end  2  of the pen needle device  1 . This is evident from  FIG. 28  which shows how the plurality of inwardly deflecting members  50 ′ a  and  50 ′ b  have been moved inwardly to the point that they will not permit (i.e., they will interfere with) re-installation of the needle tip  50 ′ back onto the threaded proximal end  2  of the pen needle device  1  owing to the fact that they effectively reduce the diameter of the distal opening of the needle tip  50 ′. As is evident from comparing  FIGS. 28 and 15 , the needle tip  50 ′ differs from the needle tip  50  in that it does not utilize any internal threads in the body of the needle tip  50 ′ (i.e., the distal opening which receives therein the threaded proximal end  2  is generally cylindrical and smooth) and with regard to the shape of the projections which extend inwardly from the members  50   a / 50 ′ a  and  50   b / 50 ′ b . That is, the projections which extend inwardly from the members  50   a  and  50   b  have a generally blunt end or rectangular-shaped cross-section whereas the projections which extend inwardly from the members  50 ′ a  and  50 ′ b  have a generally tapered end or triangular-shaped cross-section so as to threadably engage with the threads of the proximal end  2 . 
     Although not shown, the embodiment shown in  FIGS. 20-28  can instead, like the previous embodiment, utilize the needle tip cap shown in  FIGS. 47-49 . Of course, the needle tip cap  30  can have any desired configuration provided that it functions for its intended purpose, and can even be dispensed with out leaving the scope of the invention. In the later case, only the needle cap  40  (or even one of the type shown in  FIGS. 53 and 54 ) would need to be utilized (for safety reasons) and the user could activate the re-use prevention system by gripping the ring  60  and sliding it distally until it assumes the locked position. 
       FIGS. 29 and 30  show an optional needle tip  50 ″ which can be used with any of the embodiments disclosed herein. For purposes of clarity, the ring  60  has been removed. Unlike the previous embodiments which utilize two oppositely arranged inwardly deflecting members  50   a / 50 ′ a  and  50   b / 50 ′ b  which are caused to move inwardly by the ring  60 , this embodiment utilizes four equally angularly spaced members  50 ″ a ,  50 ″ b ,  50 ″ c  and  50 ″ d , which can be moved inwardly by the ring  60  to the point that they will not permit (i.e., they will interfere with) re-installation of the needle tip  50 ″ back onto the threaded proximal end  2  of the pen needle device  1  owing to the fact that they effectively reduce the diameter of the distal opening of the needle tip  50 ″. Although the members  50 ″ a ,  50 ″ b ,  50 ″ c  and  50 ″ d  are shown deflected inwardly (for purposes of clarity), of course this would not occur until the ring  60  has been moved to the locked position. The needle tip  50 ″, like the second embodiment, does not utilize any internal threads in the body of the needle tip  50 ″ (i.e., the distal opening which receives therein the threaded proximal end  2  is generally cylindrical and smooth) and utilizes projections P which extend inwardly from the members  50 ″ a ,  50 ″ b ,  50 ″ c  and  50 ″ d  and have a generally tapered end or triangular-shaped cross-section so as to threadably engage with the threads of the proximal end  2 . The projections P can extend all the way across the width of each of the members  50 ″ a ,  50 ″ b ,  50 ″ c  and  50 ″ d  (as shown in  FIG. 29 ) or they have other forms such as ones which are shorter than the width of the members  50 ″ a ,  50 ″ b ,  50 ″ c  and  50 ″ d . The projections P may even have the form of centrally disposed circular or rounded projections. Other configurations may also be utilized provided they are capable of locking with an/or frictionally engaging with the ring  60 . 
     As is evident from  FIGS. 31 and 32 , the ring  60  which can be used in the previous embodiments is generally cylindrical and has a proximal end  60   d  which engages the shoulder  30   c  of the needle tip cap  30 , a distal end having a tapered inner surface  60   c  configured to facilitate sliding over the deflecting members  50   a / 50   b  or  50 ′ a / 50 ′ b  or  50 ″ a / 50 ″ b / 50 ″ c // 50 ″ d , a circumferential recess  60   a  sized and configured to receive therein the projections P of the members  50   a / 50   b  or  50 ′ a / 50 ′ b  or  50 ″ a / 50 ″ b / 50 ″ c / 50 ″ d , and an inner cylindrical surface  60   b  which is sized to slide over the needle tip body. Of course, the ring  60  can have any desired configuration provided that it functions for its intended purpose. 
       FIG. 33  shows still another embodiment of a needle tip assembly. The needle tip assembly includes a needle tip cap  30  having various generally cylindrical portions with different diameters, a needle cap  40 , and a needle tip  50   III . As the needle tip cap  30  and the needle cap  40  of the instant embodiment are essentially identical to those used in the previous embodiment, they have been accorded the same reference numerals. In this embodiment also, the proximal end  30   a  of the needle tip cap  30  is closed while the distal end includes a circumferential flange  30   b . Similarly, the proximal end  40   a  of the needle cap  40  is closed while the distal end includes a circumferential flange  40   b . The proximal end of the needle tip  50   III  includes a needle N while the distal end includes an opening which is sized to allow the needle tip  50   III  to be mounted to the threaded proximal end  2  of the pen needle device  1 . In order to ensure that the needle tip  50   III  is prevented from being re-installed onto the proximal end  2 , the needle tip  50   III  utilizes a ring  60 ′ which can move axially from an initial position (similar to the position shown in  FIG. 21 ) to a second position (similar to the position shown in  FIG. 22 ) which causes the four inwardly deflecting members  50   III   a ,  50   III   b ,  50   III   c  and  50   III   d  to deflect inwards by an amount which is sufficient to prevent the needle tip  50   III  (after being removed) from being re-installed onto the proximal end  2 . As can be seen in  FIG. 33 , prior to the needle tip assembly being installed onto the threaded proximal end  2  (not shown in  FIG. 33 ), the four inwardly deflecting members  50   III   a ,  50   III   b ,  50   III   c  and  50   III   d  are bent outwardly or deflected outwardly by an amount which is sufficient to allow the needle tip  50   III  to be installed onto the proximal end  2  in the conventional manner, i.e., by axially sliding it on or by threading it on. 
     In a manner similar to that shown  FIG. 21 , the needle tip assembly of  FIG. 33  can be installed onto the threaded proximal end  2  without activating the re-use prevention system or mechanism, i.e., without causing the ring  60 ′ to move axially to the second or activated position. Accordingly, in the position shown in  FIG. 33 , the one or more inwardly deflecting members  50   III   a ,  50   III   b,  50     III   c and  50     III   d  are still bent outwardly or deflected outwardly by an amount which is sufficient to allow the needle tip  50   III  to be installed onto the proximal end  2 . Furthermore, while the ring  60 ′ is in the position shown in  FIG. 33 , the needle tip assembly can be removed in the conventional way, e.g., by unthreading it off of the threaded end  2 . 
     In the same way as was shown in  FIG. 22 , after the needle tip assembly shown in  FIG. 33  is installed onto the threaded proximal end  2  (similar to that shown in  FIG. 21 ), the needle tip cap  30  can be further moved axially in the distal direction (as indicated by the arrow in  FIG. 22 ) to the point that it activates the re-use prevention system or mechanism, i.e., it causes the ring  60 ′ to move axially in the distal direction until it assumes the second or activated position. Unlike the previous embodiments which provide for a locking position, i.e., characterized by engagement between the projections of the inwardly deflecting members and the inner circumferential recess of the ring, this embodiment utilizes no projections on the members  50   III   a ,  50   III   b ,  50   III   c  and  50   III   d  and does not therefore utilize the recess for receiving the same on the ring  60 ′. Instead, the ring  60 ′ merely frictionally engages with the outer surfaces of the members  50   III   a ,  50   III   b ,  50   III   c  and  50   III   d  when it is moved to the second or activated position. In order to ensure that the ring  60 ′ does not move back to the original position (after being moved to the second position), the inner circumferential surface of the ring  60 ′ and the outer surface of the members  50   III   a ,  50   III   b ,  50   III   c  and  50   III   d  can be provided with high friction surfaces such as e.g., a knurl, a high friction coating, etc. Although not shown, when the ring  60 ′ is moved to the second or activated position, the inwardly deflecting members  50   III   a ,  50   III   b ,  50   III   c  and  50   III   d  will be deflected inwardly (as was the case in the previous embodiments) so that they will biased against the proximal end  2  and frictionally engage the threads thereof when the needle tip  50   III  is unthreaded. 
     As was the case in the previous embodiments, once the needle tip assembly shown in  FIG. 33  is installed and the re-use prevention system activated, the needle tip cap  30  can be removed by sliding it off axially. Then, the needle cap  40  can also be removed axially. Once the pen needle device with the installed needle tip assembly has been used to perform an injection, the needle tip  50   III  can be removed in the following ways: one could simply grip the needle tip  50   III  in the area of the ring  60 ′ and unthread it from the threaded proximal end  2 . This is risky, of course, because the user can be inadvertently be pricked by the exposed needle N; one could re-install the needle cap  40  and then grip the needle tip  50   III  in the area of the ring  60 ′ and unthread it from the threaded proximal end  2 ; one could re-install both the needle cap  40  and the needle tip cap  30 , and then grip the needle tip cap  30  in the area just in front of the flange  30   b  and thereafter unthread the entire needle tip assembly thereby causing the needle tip  50   III  to become unthreaded from the threaded proximal end  2 ; and one could re-install only the needle tip cap  30 , and then grip the needle tip cap  30  in the area just in front of the flange  30   b  and thereafter unthread the needle tip assembly (without the cap  40 ) thereby causing the needle tip  50   III  to become unthreaded from the threaded proximal end  2 . As was the case in the previous embodiments, all of these ways are contemplated by the invention for this embodiment, with, however, the first way being the least desirable. 
     As was the case in the embodiment shown in  FIGS. 20-28 , once the needle tip  50   III  is removed from the threaded proximal end  2  (and because the ring  60 ′ has been moved to the activated position), the plurality of inwardly deflecting members  50   III   a ,  50   III   b ,  50   III   c  and  50   III   d  are caused to move inwardly to the point that they will not permit (i.e., they will interfere with) re-installation of the needle tip  50   III  back onto the threaded proximal end  2  of the pen needle device  1 . This occurs in substantially the same way as was shown in  FIG. 28  which shows how the plurality of inwardly deflecting members have been moved inwardly to the point that they will not permit (i.e., they will interfere with) re-installation of the needle tip  50   III  back onto the threaded proximal end  2  of the pen needle device  1  owing to the fact that they effectively reduce the diameter of the distal opening of the needle tip  50   III . 
     Although not shown, the embodiment shown in  FIG. 33  can, like the previous embodiments, utilize the needle tip cap shown in  FIGS. 47-49  instead of the needle tip cap  30  shown in  FIG. 33 . Of course, the needle tip cap  30  can also have any desired configuration provided that it functions for its intended purpose, and can even be dispensed with out leaving the scope of the invention. In the later case, only the needle cap  40  (or even one of the type shown in  FIGS. 53 and 54 ) would need to be utilized (for safety reasons) and the user could activate the re-use prevention system by gripping the ring  60 ′ and sliding it distally until it assumes the activated position. 
       FIG. 34  shows still another embodiment of a needle tip assembly. The needle tip assembly includes a needle tip cap  30  having various generally cylindrical portions with different diameters, a needle cap  40 , and a needle tip  50   II  of the type shown in  FIGS. 29 and 30 . As the needle tip cap  30  and the needle cap  40  of the instant embodiment are essentially identical to those used in previous embodiments, they have been accorded the same reference numerals. In this embodiment also, the proximal end  30   a  of the needle tip cap  30  is closed while the distal end includes a circumferential flange  30   b . Similarly, the proximal end  40   a  of the needle cap  40  is closed while the distal end includes a circumferential flange  40   b . The proximal end of the needle tip  50   II  includes a needle N while the distal end includes an opening which is sized to allow the needle tip  50   II  to be mounted to the threaded proximal end  2  of the pen needle device  1 . In order to ensure that the needle tip  50   II  is prevented from being re-installed onto the proximal end  2 , the needle tip  50   II  utilizes a ring  60 ′ which can move axially from an initial position (similar to the position shown in  FIG. 21 ) to a second position (similar to the position shown in  FIG. 22 ) which causes the four inwardly deflecting members  50   II   a ,  50   II   b ,  50   II   c  and  50   II   d  to deflect inwards by an amount which is sufficient to prevent the needle tip  50   II  (after being removed) from being re-installed onto the proximal end  2 . As can be seen in  FIG. 34 , prior to the needle tip assembly being installed onto the threaded proximal end  2  (not shown in  FIG. 34 ), the four inwardly deflecting members  50   II   a ,  50   II   b ,  50   II   c  and  50   II   d  are bent outwardly or deflected outwardly by an amount which is sufficient to allow the needle tip  50   II  to be installed onto the proximal end  2  in the conventional manner, i.e., by axially sliding it on or by threading it on. 
     In a manner similar to that shown  FIG. 21 , the needle tip assembly of  FIG. 34  can be installed onto the threaded proximal end  2  without activating the re-use prevention system or mechanism, i.e., without causing the ring  60 ′ to move axially to the second or activated position. Accordingly, in the position shown in  FIG. 34 , the one or more inwardly deflecting members  50   II   a ,  50   II   b ,  50   II   c  and  50   II   d  are still bent outwardly or deflected outwardly by an amount which is sufficient to allow the needle tip  50   II  to be installed onto the proximal end  2 . Furthermore, while the ring  60 ′ is in the position shown in  FIG. 34 , the needle tip assembly can be removed in the conventional way, e.g., by unthreading it off of the threaded end  2 . 
     In the same way as was shown in  FIG. 22 , after the needle tip assembly shown in  FIG. 34  is installed onto the threaded proximal end  2  (similar to that shown in  FIG. 21 ), the needle tip cap  30  can be further moved axially in the distal direction (as indicated by the arrow in  FIG. 22 ) to the point that it activates the re-use prevention system or mechanism, i.e., it causes the ring  60 ′ to move axially in the distal direction until it assumes the second or activated position. Unlike the previous embodiments which provide for a locking position, i.e., characterized by engagement between the projections of the inwardly deflecting members and the inner circumferential recess of the ring, this embodiment utilizes projections on the members  50   II   a ,  50   II   b ,  50   II   c  and  50   II   d , but does not utilize the recess for receiving the same on the ring  60 ′. Instead, the ring  60 ′ merely frictionally engages with the projections of the members  50   II   a ,  50   II   b ,  50 ″ c  and  50   II   d  (thereby causing the members  50   II   a ,  50   II   b ,  50   II   c  and  50   II   d  to deflect inwardly to a greater extent than would be the case without the projections) when it is moved to the second or activated position. In order to ensure that the ring  60 ′ does not move back to the original position (after being moved to the second position), the inner circumferential surface of the ring  60 ′ and the projections of the members  50   II   a ,  50   II   b ,  50   II   c  and  50   II   d  can be provided with high friction surfaces such as e.g., a knurl, a high friction coating, etc. Although not shown, when the ring  60 ′ is moved to the second or activated position, the inwardly deflecting members  50   II   a ,  50   II   b ,  50   II   c  and  50   II   d  will be deflected inwardly (as was the case in the previous embodiments) so that they will biased against the proximal end  2  and frictionally engage the threads thereof when the needle tip  50   II  is unthreaded. 
     As was the case in the previous embodiments, once the needle tip assembly shown in  FIG. 34  is installed and the re-use prevention system activated, the needle tip cap  30  can be removed by sliding it off axially. Then, the needle cap  40  can also be removed axially. Once the pen needle device with the installed needle tip assembly of  FIG. 34  has been used to perform an injection, the needle tip  50   II  can be removed in the following ways: one could simply grip the needle tip  50   II  in the area of the ring  60 ′ and unthread it from the threaded proximal end  2 . This is risky, of course, because the user can be inadvertently be pricked by the exposed needle N; one could re-install the needle cap  40  and then grip the needle tip  50   II  in the area of the ring  60 ′ and unthread it from the threaded proximal end  2 ; one could re-install both the needle cap  40  and the needle tip cap  30 , and then grip the needle tip cap  30  in the area just in front of the flange  30   b  and thereafter unthread the entire needle tip assembly thereby causing the needle tip  50   II  to become unthreaded from the threaded proximal end  2 ; and one could re-install only the needle tip cap  30 , and then grip the needle tip cap  30  in the area just in front of the flange  30   b  and thereafter unthread the needle tip assembly (without the cap  40 ) thereby causing the needle tip  50   II  to become unthreaded from the threaded proximal end  2 . As was the case in the previous embodiments, all of these ways are contemplated by the invention for this embodiment, with, however, the first way being the least desirable. 
     As was the case in the embodiment shown in  FIGS. 20-28 , once the needle tip  50   II  is removed from the threaded proximal end  2  (and because the ring  60 ′ has been moved to the activated position), the plurality of inwardly deflecting members  50   II   a ,  50   II   b ,  50   II   c  and  50   II   d  are caused to move inwardly to the point that they will not permit (i.e., they will interfere with) re-installation of the needle tip  50   II  back onto the threaded proximal end  2  of the pen needle device  1 . This occurs in substantially the same way as was shown in  FIG. 28  which shows how the plurality of inwardly deflecting members have been moved inwardly to the point that they will not permit (i.e., they will interfere with) re-installation of the needle tip  50   II  back onto the threaded proximal end  2  of the pen needle device  1  owing to the fact that they effectively reduce the diameter of the distal opening of the needle tip  50   II . 
     Although not shown, the embodiment shown in  FIG. 34  can, like the previous embodiments, utilize the needle tip cap shown in  FIGS. 47-49  instead of the needle tip cap  30  shown in  FIG. 34 . Of course, the needle tip cap  30  can also have any desired configuration provided that it functions for its intended purpose, and can even be dispensed with out leaving the scope of the invention. In the later case, only the needle cap  40  (or even one of the type shown in  FIGS. 53 and 54 ) would need to be utilized (for safety reasons) and the user could activate the re-use prevention system by gripping the ring  60 ′ and sliding it distally until it assumes the activated position. 
       FIG. 35  shows still another embodiment of a needle tip assembly. The needle tip assembly includes a needle tip cap  30  having various generally cylindrical portions with different diameters, a needle cap  40 , and a needle tip  50   III  of the type shown in  FIG. 33 . As the needle tip cap  30  and the needle cap  40  of the instant embodiment are essentially identical to those used in the previous embodiments, they have been accorded the same reference numerals. In this embodiment also, the proximal end  30   a  of the needle tip cap  30  is closed while the distal end includes a circumferential flange  30   b . Similarly, the proximal end  40   a  of the needle cap  40  is closed while the distal end includes a circumferential flange  40   b . The proximal end of the needle tip  50   III  includes a needle N while the distal end includes an opening which is sized to allow the needle tip  50   III  to be mounted to the threaded proximal end  2  of the pen needle device  1 . In order to ensure that the needle tip  50   III  is prevented from being re-installed onto the proximal end  2 , the needle tip  50   III  utilizes a ring  60 ″ which can move axially from an initial position (similar to the position shown in  FIG. 21 ) to a second position (similar to the position shown in  FIG. 22 ) which causes the four inwardly deflecting members  50   III   a ,  50   III   b ,  50   III   c  and  50   III   d  to deflect inwards by an amount which is sufficient to prevent the needle tip  50   III  (after being removed) from being re-installed onto the proximal end  2 . As can be seen in  FIG. 35 , prior to the needle tip assembly being installed onto the threaded proximal end  2  (not shown in  FIG. 35 ), the four inwardly deflecting members  50   III   a ,  50   III   b ,  50   III   c  and  50   III   d  are bent outwardly or deflected outwardly by an amount which is sufficient to allow the needle tip  50   III  to be installed onto the proximal end  2  in the conventional manner, i.e., by axially sliding it on or by threading it on. 
     In a manner similar to that shown  FIG. 21 , the needle tip assembly of  FIG. 35  can be installed onto the threaded proximal end  2  without activating the re-use prevention system or mechanism, i.e., without causing the ring  60 ″ to move axially to the second or activated position. Accordingly, in the position shown in  FIG. 35 , the one or more inwardly deflecting members  50   III   a ,  50   III   b ,  50   III   c  and  50   III   d  are still bent outwardly or deflected outwardly by an amount which is sufficient to allow the needle tip  50   III  to be installed onto the proximal end  2 . Furthermore, while the ring  60 ″ is in the position shown in  FIG. 35 , the needle tip assembly can be removed by e.g., sliding or threading it off of the threaded end  2 . 
     In the same way as was shown in  FIG. 22 , after the needle tip assembly shown in  FIG. 35  is installed onto the threaded proximal end  2  (similar to that shown in  FIG. 21 ), the needle tip cap  30  can be further moved axially in the distal direction (as indicated by the arrow in  FIG. 22 ) to the point that it activates the re-use prevention system or mechanism, i.e., it causes the ring  60 ″ to move axially in the distal direction until it assumes the second or activated position. Unlike the previous embodiments which provide for a locking position, i.e., characterized by engagement between the projections of the inwardly deflecting members and the inner circumferential recess of the ring, this embodiment utilizes no projections on the members  50   III   a ,  50   III   b ,  50   III   c  and  50   III   d  and does not therefore utilize the recess for receiving the same on the ring  60 ″. Furthermore, unlike the embodiment shown in  FIG. 33 , the ring  60 ″ of this embodiment utilizes no inner tapered section. Instead, the ring  60 ″ merely frictionally engages with the outer surfaces of the members  50   III   a ,  50   III   b ,  50   III   c  and  50   III   d  when it is moved to the second or activated position. In order to ensure that the ring  60 ″ does not move back to the original position (after being moved to the second position), the inner circumferential surface of the ring  60 ″ and the outer surface of the members  50   III   a ,  50   III   b ,  50   III   c  and  50   III   d  can be provided with high friction surfaces such as e.g., a knurl, a high friction coating, etc. Although not shown, when the ring  60 ″ is moved to the second or activated position, the inwardly deflecting members  50   III   a ,  50   III   b ,  50   III   c  and  50   III   d  will be deflected inwardly (as was the case in the previous embodiments) so that they will biased against the proximal end  2  and frictionally engage the threads thereof when the needle tip  50   III  is unthreaded. 
     As was the case in the previous embodiments, once the needle tip assembly shown in  FIG. 35  is installed and the re-use prevention system activated, the needle tip cap  30  can be removed by sliding it off axially. Then, the needle cap  40  can also be removed axially. Once the pen needle device with the installed needle tip assembly has been used to perform an injection, the needle tip  50   III  can be removed in the following ways: one could simply grip the needle tip  50   III  in the area of the ring  60 ″ and unthread it from the threaded proximal end  2 . This is risky, of course, because the user can be inadvertently be pricked by the exposed needle N; one could re-install the needle cap  40  and then grip the needle tip  50   III  in the area of the ring  60 ″ and unthread it from the threaded proximal end  2 ; one could re-install both the needle cap  40  and the needle tip cap  30 , and then grip the needle tip cap  30  in the area just in front of the flange  30   b  and thereafter unthread the entire needle tip assembly thereby causing the needle tip  50   III  to become unthreaded from the threaded proximal end  2 ; and one could re-install only the needle tip cap  30 , and then grip the needle tip cap  30  in the area just in front of the flange  30   b  and thereafter unthread the needle tip assembly (without the cap  40 ) thereby causing the needle tip  50   III  to become unthreaded from the threaded proximal end  2 . As was the case in the previous embodiments, all of these ways are contemplated by the invention for this embodiment, with, however, the first way being the least desirable. 
     As was the case in the embodiment shown in  FIGS. 20-28 , once the needle tip  50   III  is removed from the threaded proximal end  2  (and because the ring  60 ″ has been moved to the activated position), the plurality of inwardly deflecting members  50   III   a ,  50   III   b ,  50   III   c  and  50   III   d  are caused to move inwardly to the point that they will not permit (i.e., they will interfere with) re-installation of the needle tip  50   III  back onto the threaded proximal end  2  of the pen needle device  1 . This occurs in substantially the same way as was shown in  FIG. 28  which shows how the plurality of inwardly deflecting members have been moved inwardly to the point that they will not permit (i.e., they will interfere with) re-installation of the needle tip  50   III  back onto the threaded proximal end  2  of the pen needle device  1  owing to the fact that they effectively reduce the diameter of the distal opening of the needle tip  50   III . 
     Although not shown, the embodiment shown in  FIG. 35  can, like the previous embodiments, utilize the needle tip cap shown in  FIGS. 47-49  instead of the needle tip cap  30  shown in  FIG. 33 . Of course, the needle tip cap  30  can also have any desired configuration provided that it functions for its intended purpose, and can even be dispensed with out leaving the scope of the invention. In the later case, only the needle cap  40  (or even one of the type shown in  FIGS. 53 and 54 ) would need to be utilized (for safety reasons) and the user could activate the re-use prevention system by gripping the ring  60 ″ and sliding it distally until it assumes the activated position. 
       FIGS. 36 and 37  show an optional needle tip  50   IV  which can be used with any of the embodiments disclosed herein. Unlike the previous embodiments which utilize a essentially rigid or semi-rigid ring, this embodiment utilizes an elastic-type ring  60   III ; that is a ring which functions like an expanded rubber band that wants to contract. Indeed, the invention contemplates that the ring  60   III  can be a rubber band ring or even a split spring metal ring which wants to contract but is kept expanded by virtue of being mounted to a portion of the body of the needle tip  50   IV  which prevents its contraction. Furthermore, unlike the previous embodiments which utilize inwardly deflecting members which are caused to move inwardly by the ring, this embodiment utilizes four equally angularly spaced slots  50   IV   a ,  50   IV   b ,  50   IV   c  and  50   IV   d , which weakens the distal end of the needle tip  50   IV  to the point that when, the ring  60   III  is moved over the slots  50   IV   a ,  50   IV   b ,  50   IV   c  and  50   IV   d , the distal end of the needle tip  50   IV  will deflect inwardly to the point that it will not permit (i.e., it will interfere with) re-installation of the needle tip  50   IV  back onto the threaded proximal end  2  of the pen needle device  1  owing to the fact that they effectively reduce the diameter of the distal opening of the needle tip  50   IV . The needle tip  50   IV , like the second embodiment, does not utilize any internal threads in the body of the needle tip  50   IV  (i.e., the distal opening which receives therein the threaded proximal end  2  is generally cylindrical and smooth). 
     As is evident from  FIG. 38 , once the needle tip  50   IV  is removed from the threaded proximal end  2  (and because the ring  60   III  has been moved to the activated position), the distal end of the needle tip  50   VI  deflects inwardly to the point that it will not permit (i.e., will interfere with) re-installation of the needle tip  50   IV  back onto the threaded proximal end  2  of the pen needle device  1 . When this occurs, the distal end of the needle tip  50   IV  effectively reduces the diameter of the distal opening of the needle tip  50   IV . 
       FIGS. 39 and 40  show an optional needle tip  50   V  which can be used with any of the needle tip assembly embodiments disclosed herein. The ring  60  can be, by way of non-limiting example, of the type described above in  FIGS. 31 and 32 . The needle tip  50   V  can be, by way of non-limiting example, of the type described above in  FIGS. 29 and 30 , except that it additionally utilizes a plurality of e.g., equally angularly spaced, guide/engaging projections  50   V e which are sized and configured to slide within correspondingly placed guide/engaging recesses  30 ′ g  arranged on the needle tip cap  30 ′. This embodiment similarly utilizes four equally angularly spaced members  50   II   a ,  50   II   b ,  50   V   c  and  50   V   d , which can be moved inwardly by the ring  60  to the point that they will not permit (i.e., they will interfere with) re-installation of the needle tip  50   V  back onto the threaded proximal end  2  of the pen needle device  1  owing to the fact that they effectively reduce the diameter of the distal opening of the needle tip  50   V . 
       FIG. 40  shows a needle tip cap  30 ′ which can be used with the needle tip  50   V  shown in  FIG. 39 . The needle tip cap  30 ′ is similar to the cap shown in  FIGS. 18 and 19  except that it also utilizes e.g., equally angularly spaced, guide/engaging recesses  30 ′ g  which are sized and configured to slidably receive therein correspondingly placed guide/engaging projections  50   V e arranged on the needle tip  50   V . The needle tip cap  30 ′ has a closed proximal end  30 ′ a , an open distal end having a circumferential flange  30 ′ b , a distal opening  30 ′ c  sized to receive therein the ring  60 , a shoulder  30 ′ c  which engages with a distal end of the ring  60  so as to cause the ring  60  to move to the locked position, a generally circumferential surface  30 ′ e  which is sized to slide over an outer surface of the needle tip  50   V  and allow for engagement between guide/engaging projections  50   V e and guide/engaging recesses  30 ′ g . Of course, the needle tip cap  30 ′ can have any desired configuration provided that it functions for its intended purpose. 
       FIGS. 41-44  show still another embodiment of a needle tip assembly. The needle tip assembly includes a needle tip cap  300  having a generally cylindrical configuration, a needle cap  40 , and a needle tip  50   II  of the type shown in  FIGS. 29 and 30 , and except that the ring  60   IV  has a different configuration. In this embodiment, the ring  60   IV  is generally cylindrical and has a proximal end  60   IV   d  which engages the shoulder  300   c  of the needle tip cap  300 , a distal end having a tapered inner surface  60   IV c configured to facilitate sliding over the deflecting members  50 ″ a / 50 ″ b / 50 ″ c // 50 ″ d , a circumferential recess  60   IV   a  sized and configured to receive therein the projections P of the members  50 ″ a / 50 ″ b / 50 ″ c // 50 ″ d , and an inner cylindrical surface  60   IV   b  which is sized to slide over the needle tip body. Of course, the ring  60   IV  can have any desired configuration provided that it functions for its intended purpose. Additionally, the ring  60   IV  has a generally circumferential proximal flange  60   IV   d  which prevents the needle tip cap  300  from sliding off the ring  60   IV  in the proximal direction. The ring  60   IV  also has a generally circumferential retaining projection  60   IV   f  which ensures that the needle tip cap  300  is able to move the ring  60   IV  in the distal direction so as to cause it to lock to the needle tip  50 ″. However, after the ring  60   IV  becomes locked to the needle tip  50 ″, the projection  60   IV f will not be able to prevent further movement of the cap  300  and is, in fact, configured to allow (upon exertion of a predetermined force) the inwardly projecting circumferential projection  300   e  to pass over the projection  60   IV   f  until the annular surface  300   c  of the projection  300   e  engages the proximal shoulder of the pen needle device  1 . This is shown in  FIG. 42 . As the needle cap  40  of the instant embodiment is essentially identical to that used in the previous embodiment, it has been accorded the same reference numeral. In this embodiment, the proximal end  300   a  of the needle tip cap  300  is open (unlike the previous embodiments) while the distal end is configured to slide over the proximal portion of the device  1 . Similarly, the proximal end  40   a  of the needle cap  40  is closed while the distal end includes a circumferential flange  40   b . The proximal end of the needle tip  50   II  includes a needle N while the distal end includes an opening which is sized to allow the needle tip  50   II  to be mounted to the threaded proximal end  2  of the pen needle device  1 . In order to ensure that the needle tip  50   II  is prevented from being re-installed, onto the proximal end  2 , the needle tip  50   II  utilizes the ring  60   IV  which can move axially from an initial position (shown in  FIG. 41 ) to a second or locked position (shown in  FIG. 42 ) which causes the four inwardly deflecting members  50   II   a ,  50   II   b ,  50   II   c  and  50   II   d  to deflect inwards by an amount which is sufficient to prevent the needle tip  50   II  (after being removed) from being re-installed onto the proximal end  2 . As can be seen in  FIG. 41 , prior to activation, the four inwardly deflecting members  50   II   a ,  50   II   b ,  50   II   c  and  50   III   d  are bent outwardly or deflected outwardly by an amount which is sufficient to allow the needle tip  50   II  to be installed onto the proximal end  2 , i.e., by axially sliding it on or by threading it on. 
     As can be seen in  FIG. 41 , the needle tip assembly of  FIG. 41  can be installed onto the threaded proximal end  2  without activating the re-use prevention system or mechanism, i.e., without causing the ring  60   IV  to move axially to the second or activated position. Accordingly, in the position shown in  FIG. 41 , the one or more inwardly deflecting members  50   II   a ,  50   II   b ,  50   II   c  and  50   II   d  are still bent outwardly or deflected outwardly by an amount which is sufficient to allow the needle tip  50   II  to be installed onto the proximal end  2 . Furthermore, while the ring  60   IV  is in the position shown in  FIG. 41 , the needle tip assembly can be removed, e.g., by sliding it off of the threaded end  2 . 
     As is evident from  FIG. 42 , after the needle tip assembly shown in  FIG. 41  is installed onto the threaded proximal end  2 , the needle tip cap  300  can be further moved axially in the distal direction (as indicated by the arrow in  FIG. 42 ) to the point that it activates the re-use prevention system or mechanism, i.e., it causes the ring  60   IV  to move axially in the distal direction until it assumes the second or locked or activated position. Like many of the previous embodiments, locking occurs because of engagement between the projections of the inwardly deflecting members and the inner circumferential recess of the ring  60   IV . This locking engagement also ensures that the ring  60   IV  does not move back to the original position (after being moved to the second position) when the cap  300  is moved in the proximal direction to protect inadvertent contact with the needle N (see  FIG. 44 ). As is evident from  FIG. 42 , when the ring  60   IV  is moved to the second or activated position, the inwardly deflecting members  50   II   a ,  50   II   b ,  50   II   c  and  50   II   d  will be deflected inwardly (as was the case in the previous embodiments) so that they will biased against the proximal end  2  and frictionally engage the threads thereof when the needle tip  50   II  is unthreaded. 
     Once the needle tip assembly shown in  FIG. 41  is installed and the re-use prevention system activated (see  FIG. 42 ), the needle tip cap  300  can be, after being in the position allowing it to be used for injection (see  FIG. 43 ), slid in the proximal direction (see  FIG. 44 ), but, unlike the previous embodiments, it is not removed. Then, the needle cap  40  can also be removed axially (in a manner similar to the previous embodiments). Once the pen needle device with the installed needle tip assembly has been used to perform an injection, the needle tip  50   II  can be removed in the following way: one could re-install the needle cap  40  and then grip the needle tip cap  300  and slid it in the proximal direction until it assumes the position shown in  FIG. 44 ; or one could simply grip the needle tip cap  300  and slid it in the proximal direction until it assumes the position shown in  FIG. 44  without re-installing the needle cap  40 . In either case, the user can then safely remove the entire needle tip assembly by either removing it axially or unthreading it axially. Of course, once removed, the needle tip assembly will be prevented from being re-installed because of the configuration of the ring  60   IV  and  50 ″. As was the case in the previous embodiments, all of these ways are contemplated by the invention for this embodiment. 
     Although not shown, the embodiment shown in  FIGS. 41-44  can, like the previous embodiments, utilize a needle cap of the type shown in  FIGS. 53 and 54 ). 
       FIG. 45  shows a needle tip assembly according to still another embodiment of the invention. The needle tip assembly is substantially similar to that shown in  FIGS. 41-44  except that it utilizes a coil compression spring S to bias the needle tip cap  300  in a proximal direction, i.e., towards the original position. 
       FIG. 46  shows still another embodiment of a needle tip  50   VI  which can be used in one or more of the herein disclosed embodiments. The needle tip  50   VI  be utilized with a needle tip cap of the types disclosed herein or not with the former being preferred. A needle cap  40  (not shown) can also be utilized. The needle tip  50   VI  can be substantially similar to the embodiment shown in  FIGS. 29 and 30 , except that it also includes a circumferential retaining shoulder RS which ensures that the ring  60   V  is axially retained on the body of the needle tip  50   VI . The proximal end of the needle tip  50   VI  includes a needle N while the distal end includes an opening which is sized to allow the needle tip  50   VI  to be mounted to the threaded proximal end  2  of the pen needle device  1 . In order to ensure that the needle tip  50   VI  is prevented from being re-installed onto the proximal end  2 , the needle tip  50   VI  utilizes a ring  60   V  which can move axially from an initial position (similar to the position shown in  FIG. 21 ) to a second or activated position (shown in  FIG. 46 ) which causes the four inwardly deflecting members  50   II   a ,  50   II   b ,  50 ″ c  and  50 ″ d  to deflect inwards by an amount which is sufficient to prevent the needle tip  50   VI  (after being removed) from being re-installed onto the proximal end  2 . Although not shown, prior to the needle tip assembly being installed onto the threaded proximal end  2 , the four inwardly deflecting members  50   VI   a ,  50   VI   b ,  50   VI   c  and  50   VI   d  are bent outwardly or deflected outwardly by an amount which is sufficient to allow the needle tip  50   VI  to be installed onto the proximal end  2 . 
     In the same way as was shown in  FIG. 22 , after the needle tip assembly shown in  FIG. 46  is installed onto the threaded proximal end  2 , the needle tip cap  30  (not shown) can be further moved axially in the distal direction to the point that it activates the re-use prevention system or mechanism, i.e., it causes the ring  60   V  to move axially in the distal direction until it assumes the second or activated position shown in  FIG. 46 . Unlike the previous embodiments which provide for a locking position, i.e., characterized by engagement between the projections of the inwardly deflecting members and the inner circumferential recess of the ring, this embodiment utilizes projections on the members  50   VI   a ,  50   VI   b ,  50   VI   c  and  50   VI   d  and a recess in the ring  60   V  for receiving the same, but does not provide for a locking engagement between these members. Instead, the inner recess of the ring  60   V  merely frictionally engages with the projections of the members  50   VI   a ,  50   VI   b ,  50   VI   c  and  50   VI   d  when it is moved to the second or activated position. In order to ensure that the ring  60   V  does not move back to the original position (after being moved to the second position), the inner circumferential surface of the ring  60   V  and the outer surface of the members  50   VI   a ,  50   VI   b ,  50   VI   c  and  50   VI   d  can be provided with high friction surfaces such as e.g., a knurl, a high friction coating, etc. As shown in  FIG. 46 , when the ring  60   V  is moved to the second or activated position, the inwardly deflecting members  50   VI   a ,  50   VI   b ,  50   VI   c  and  50   VI   d  are deflected inwardly (as was the case in the previous embodiments) so that they will biased against the proximal end  2  and frictionally engage the threads thereof when the needle tip  50   VI  is unthreaded. 
     Once the re-use prevention system is activated (as shown in  FIG. 46 ), the needle tip cap  30  (not shown) can be removed by sliding it off axially. Then, the needle cap  40  (not shown) can also be removed axially. Once the pen needle device with the installed needle tip assembly has been used to perform an injection, the needle tip  50   VI  can be removed in the following ways: one could simply grip the needle tip  50   VI  in the area of the ring  60   V  and unthread it from the threaded proximal end  2 . This is risky, of course, because the user can be inadvertently be pricked by the exposed needle N; one could re-install the needle cap  40  and then grip the needle tip  50   VI  in the area of the ring  60   V  and unthread it from the threaded proximal end  2 ; one could re-install both the needle cap  40  and the needle tip cap  30 , and then grip the needle tip cap  30  in the area just in front of the flange  30   b  and thereafter unthread the entire needle tip assembly thereby causing the needle tip  50 ″ to become unthreaded from the threaded proximal end  2 ; and one could re-install only the needle tip cap  30 , and then grip the needle tip cap  30  in the area just in front of the flange  30   b  and thereafter unthread the needle tip assembly (without the cap  40 ) thereby causing the needle tip  50   VI  to become unthreaded from the threaded proximal end  2 . As was the case in the previous embodiments, all of these ways are contemplated by the invention for this embodiment, with, however, the first way being the least desirable. 
     As was the case in, e.g., the embodiment shown in  FIGS. 20-28 , once the needle tip  50   VI  is removed from the threaded proximal end  2  (and because the ring  60   V  has been moved to the activated position), the plurality of inwardly deflecting members  50   VI   a ,  50   VI   b ,  50   VI   c  and  50   VI   d  are caused to move inwardly to the point that they will not permit (i.e., they will interfere with) re-installation of the needle tip  50   VI  back onto the threaded proximal end  2  of the pen needle device  1 . This occurs in substantially the same way as was shown in  FIG. 28  which shows how the plurality of inwardly deflecting members have been moved inwardly to the point that they will not permit (i.e., they will interfere with) re-installation of the needle tip  50   VI  back onto the threaded proximal end  2  of the pen needle device  1  owing to the fact that they effectively reduce the diameter of the distal opening of the needle tip  50   VI . 
     Although not shown, the embodiment shown in  FIG. 46  can, like the previous embodiments, utilize the needle tip cap shown in  FIGS. 47-49  instead of the needle tip cap  30 . Of course, the needle tip cap  30  can also have any desired configuration provided that it functions for its intended purpose, and can even be dispensed with out leaving the scope of the invention. In the later case, only the needle cap  40  (or even one of the type shown in  FIGS. 53 and 54 ) would need to be utilized (for safety reasons) and the user could activate the re-use prevention system by gripping the ring  60   V  and sliding it distally until it assumes the activated position. 
       FIGS. 47-49  show an optional needle tip cap  3000  which can be used in one or more of the embodiments described herein. The needle tip cap  3000  can be similar to that shown in  FIGS. 18 and 19  except that it utilize a two-piece folding connectable construction instead of the simple one-piece integral construction shown in  FIGS. 18 and 19 . In order to connect the two parts  3000 A and  3000 B, the cap  3000  utilizes a living hinge LH at one end and a lock system utilizing a lock member LM and a locking projection LP. This type of cap is advantageous because it allows the user to position the cap  3000  from the side instead of from the needle end. As a result, one can install the cap  3000  with a lower risk of being inadvertently punctured by the needle. 
       FIGS. 50-52  show another non-limiting embodiment of a needle tip assembly which can be installed onto the proximal end of pen needle device  1 . The needle tip assembly is similar to that shown in the prior art  FIGS. 1-7  except that the needle tip  50   VII  includes a rear end cap member EC which is mounted to the needle tip body via a living hinge LH′. The needle tip cap also includes a mechanism which allows the rear cap member EC to temporarily lock thereto.  FIG. 51  shows the needle tip assembly of  FIG. 50  after the rear end cap EC is unlocked from the needle tip cap and been deflected distally. In this position, the needle tip cap can then be removed in the manner shown in  FIG. 4 .  FIG. 52  shows the needle tip  50   VII  used in the embodiment shown in  FIG. 50  and illustrates how the rear cap EC can be deflected via the living hinge LH′ to a position prior to covering the distal end of the needle tip  50   VII . The end cap EC can also be utilized in one or more of the embodiments disclosed herein. 
       FIG. 53  shows a needle tip assembly according to another embodiment of the invention. The needle tip is similar to that shown in the prior art  FIGS. 1-7  except that the needle tip includes a needle cap member  40 ′ which is mounted to the needle tip body via a living hinge LH″. The needle cap also includes a mechanism which allows the needle cap member  40 ′ to temporarily lock to the needle tip body.  FIG. 54  shows the needle tip assembly of  FIG. 53  after the needle cap  40 ′ is unlocked from the needle tip and been deflected distally. In this position, the needle tip can be used to perform an injection. 
       FIGS. 55-57  show one non-limiting way in which a plurality of needle tip assemblies of either the prior art variety shown in  FIGS. 2-7  or those of the invention described herein can be packaged in a housing H. The housing H performs the function of storing a number of needle tip assemblies and also functions as a tool for installing one needle tip assembly at a time onto the end of a pen needle. The housing H can be a generally cylindrical member with an open front end and a closed rear end. A plurality of spring retaining members RM can be arranged near the front open end. These members RM normally extend inwardly to prevent the needle tip assembly which is to be installed onto a pen needle from moving back into the housing H. Once in the position shown in  FIG. 55 , the user can grip the housing H and use it to force it onto the pen needle end  1 . Of course, the user will first remove the removable sealing material layer (not shown) which is typically adhesively arranged on the open end of the needle tip cap, e.g.,  3 . Once the housing H is used to install one of the needle tip assemblies, the user can either leave the housing in the position shown in  FIG. 56 . Then, when the user desires to install a fresh needle tip assembly on the pen needle end  1 , the user can slide the push button PB in the direction of the open end of the housing H until the next needle tip assembly reaches the position shown in  FIG. 57 . In this regard, the inwardly bent free ends of retaining members RM (a total of e.g., four, can be utilized) are designed to deflect outwardly in order to allow the next needle tip assembly to pass by. Installation can then occur in the same way as was described with regard to  FIG. 55 . Once, all of the needle tip assemblies, e.g., five, are utilized, the housing H can be discarded. As is evident from  FIGS. 55-57 , the push-button slides within an elongated slot SL formed in the side wall of the housing H and has an inner portion which is configured to engage and cause to move the needle tip assemblies arranged in series. Of course, the housing H can also have other configurations and can house as few as two or more than five assemblies. 
     The pen needle device 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 needle tip assembly 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. 
     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.