Abstract:
A medical implement is provided with a hub and a piercing element that projects distally from the hub. The protective cap is removably engaged with the proximal end of the hub. An IV shield is threadedly engaged with the distal end of the hub and protectively covers the piercing element. A hinged shield is hingedly mounted to the hub and can be rotated from a first position substantially adjacent the IV shield to a second position where the hinged shield is spaced rotationally from the IV shield and finally to a third position where the hinged shield encloses the piercing element. The hinged shield must be rotated from the first position to the second position to threadedly disengage the IV shield and to expose the piercing element for use. After use, the hinged shield is rotated from the second position into the third position for protectively enclosing the piercing element.

Description:
RELATED APPLICATION  
       [0001]    This application is a continuation-in-part application of U.S. patent application Ser. No. 09/378,976 which was filed Aug. 23, 1999. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to a shield for a needle and more particularly to a safety shield assembly that may be used in conjunction with a syringe assembly, a hypodermic needle, a needle assembly, a needle assembly with a needle holder, a blood collection needle, a blood collection set, an intravenous infusion set or other fluid handing devices or assemblies that contain piercing elements.  
         BACKGROUND OF THE INVENTION  
         [0003]    Disposable medical devices having piercing elements for administering a medication or withdrawing a fluid, such as hypodermic needles, blood collecting needles, fluid handling needles and assemblies thereof, require safe and convenient handling. The piercing elements include, for example, pointed needle cannula or blunt ended cannula. The piercing element typically is mounted to a hub and extends distally from the hub. A second piercing element may extend proximally from the hub, and may include a non-patient needle that can be placed in communication with a container, such as an evacuated fluid collection container. In other instances, the proximal end of the hub is configured for mating with a medical implement, such as a syringe or a needle holder.  
           [0004]    Safe and convenient handling of disposable medical devices is recognized by those in the medical arts so as to minimize exposure to blood borne pathogens. Safe and convenient handling of disposable medical devices results in the disposal of the medical devices intact.  
           [0005]    As a result of this recognition, numerous devices have been developed for shielding needles after use. Many of these devices are somewhat complex and costly. In addition, many of these devices are cumbersome to use in performing procedures. Furthermore, some of the devices are so specific that they preclude use of the device in certain procedures or with certain devices and/or assemblies. For example, some devices employ very short thin needle cannulas. A shield designed to lock near the distal end of one needle cannula might not engage a much shorter needle cannula. Additionally, a shield designed to lock with a wider gauge needle cannula might be more likely to generate a spray upon engaging a much narrower needle cannula. Furthermore, it may be desirable to reduce the force required to effect shielding without reducing the audible and tactile indications of complete shielding.  
           [0006]    Some medical devices employ a plurality of shields, sleeves and/or caps to achieve sterility and to prevent accidental needle sticks prior to use and to further prevent accidental needle sticks after use. For example, some medical devices employ a rigid generally tubular cap or sleeve telescoped over the piercing element that projects from the distal end of the hub. A second cap or sleeve is telescoped into or over the proximal end of the hub to provide sterility and to prevent accidental sticks with any piercing element that projects from the proximal end of the hub. A hinged shield may be provided on the medical device to prevent accidental sticks with at least the distally directed piercing element after use of the medical device.  
           [0007]    Manufacturers of medical devices have preferred methods of use to optimize safe handling, to ensure maximum cleanliness and to avoid accidental sticks. In particular, the user is instructed to remove the proximal cap or sleeve from the hub before removing the sleeve over the piercing element at the distal end of the hub and before manipulating any hinged shield that may be mounted to the hub. The proximal end of the hub then is mounted to the medical device with the distal sleeve in place over the piercing element that projects distally from the hub. Any hinged shield that may be provided on the device then is rotated into a position away from the piercing element, while still keeping the distal sleeve telescoped over the piercing element. The distal sleeve is removed immediately prior to use and is discarded. The medical device then is employed in a specified safe manner. After use, the hinged shield or other such post-use shielding element is moved into a position surrounding the piercing element, and at least portions of the medical device are disposed of in a safe manner.  
           [0008]    A need exists for a safety shield assembly: (i) that is manufactured easily; (ii) that is applicable to many devices; (iii) that is simple to use with one hand; (iv) that can be disposed of safely; (v) that does not interfere with normal practices of needle use; (vi) that has tactile features whereby the user may be deterred from contacting the needle, the user may easily orient the needle with the patient and easily actuate and engage the shield assembly; (vii) that has visual features whereby the user may be deterred from contacting the needle, the user may easily orient the needle with the patient and easily actuate and engage the shield assembly; (viii) that is not bulky; (ix) that includes means for minimizing exposure to the user of residual fluid leaking from the needle; and (x) provides minimal exposure to the user because the needle shield is immediately initiated by the user after the needle is withdrawn from the patient&#39;s vein. It also would be desirable to provide a safety shield assembly with greater assurance that the preferred unshielding and shielding steps are carried out in a specified safe sequence.  
         SUMMARY OF THE INVENTION  
         [0009]    The invention relates to a fluid handling device with opposite proximal and distal ends. A piercing element projects at the distal end of the fluid handling device. The piercing element at the distal end of the fluid handling device may comprise a metallic needle cannula, a plastic cannula, a blunt cannula or other piercing element for delivering a fluid to a patient or for obtaining a specimen of fluid. The proximal end of the fluid handling device is configured for communication with another medical implement. For example, the proximal end of the fluid handling device may be configured for mating to a syringe, a fitting on a fluid transfer line, a holder for receiving an evacuated tube or other known medical implement for delivering a fluid to a patient or for obtaining a sample of fluid. In particular, the proximal end of the fluid handling device may define a female Luer fitting. Alternatively, the proximal end of the fluid handling device may comprise a proximal piercing element, such as a non-patient needle intended for communication with an evacuated tube or other medical device.  
           [0010]    The fluid handling device further comprises a cap or proximal sleeve mounted over at least portions of the proximal end of the fluid handling device. The cap or proximal sleeve mounted to the proximal end of the fluid handling device has a configuration dependent on the specific structure provided at the proximal end of the fluid handling device. For example, a tubular proximal sleeve may be mounted to the proximal end of the fluid handling device for those instances where the fluid handling device includes a proximal piercing element. Alternatively, an end cap may be mounted to the proximal end of the fluid handling device for those instances where the fluid handling device is configured for mating with a syringe, a fitting or other medical implement. The proximal sleeve or end cap may be frictionally or threadedly mounted to proximal portions of the fluid handling device.  
           [0011]    A distal sleeve is telescoped removably to distal portions of the fluid handling device and is configured for protectively covering the piercing element. Proximal portions of the distal sleeve preferably are connected threadedly to the fluid handling device. For example, proximal portions of the distal sleeve may be formed with an array of external threads that can threadedly engage an array of internal threads at or near proximal portions of the distal piercing element. Alternatively, proximal portions of the distal sleeve may include an array of internal threads that engage external threads on the fluid handling device.  
           [0012]    The fluid handling device further comprises a hinged safety shield that is intended for shielding the distal piercing element after use. The hinged shield is preliminarily mounted in a position partly surrounding the distal sleeve. However, the dimensions of the distal sleeve prevent the hinged shield from rotating completely over the distal sleeve. The hinged shield is intended to be rotated away from the distal sleeve and away from the piercing element covered by the distal sleeve prior to use of a fluid handling device. After use, the hinged shield is rotated toward the distal piercing element and locks into engagement around the distal piercing element, as explained further herein.  
           [0013]    The initial position of the hinged shield in partly surrounding relationship to the distal sleeve prevents or complicates any attempt to threadedly disengage the distal sleeve from the fluid handling device. Hence, the hinged shield must be rotated into the ready-to-use position prior to removal of the distal sleeve. Thus, the fluid handling device inherently ensures that the user of the fluid handling device will follow the preferred safe sequence of first rotating the hinged shield into the ready-to-use position and then removing the distal sleeve. The user is substantially prevented from following the less safe sequence of first removing the distal sleeve and then rotating the hinged shield while the distal piercing element is exposed.  
           [0014]    The hinged shield may take many forms. Preferably, the hinged shield comprises a rearward end, a forward end, a slot or longitudinal opening for housing the used needle in the forward end, means for securing the needle in the slot, means for guiding the needle into the slot, means for connecting the hinged shield and the fluid handling device, means for guiding the user&#39;s fingers to move the hinged shield into various positions, and means for retaining the hinged shield securely over the used needle.  
           [0015]    Desirably, the means for connecting the hinged shield to the fluid handling device is a collar. Preferably, the hinged shield is connected movably to a collar which is connected to a fluid handling device.  
           [0016]    Preferably, the hinged shield is connected to the collar by a hanger bar that engages with a hook arm on the collar so that the hinged shield may be pivoted with respect to the collar into several positions. It is within the purview of the present invention to include any structure for connecting the hinged shield to the collar so that the shield may be pivoted with respect to the collar. These structures include known mechanical hinges and various linkages, living hinges, or combinations of hinges and linkages.  
           [0017]    Most preferably, the hinged shield is connected to the collar by an interference fit between the hanger bar and the hook bar. Therefore, the shield always is oriented in a stable position and will not move forward or backwards unless movement of the hinged shield relative to the hanger bar and the hook bar is initiated by the user.  
           [0018]    Alternatively, the hinged shield and collar may be a unitary one-piece structure. The one-piece structure may be obtained by many methods, including molding the shield and the collar as a one-piece unit, thereby eliminating the separate shield and collar during the manufacturing assembly process.  
           [0019]    The assembly of the present invention may further comprise tactile and visual means for deterring the user from contacting the needle, providing easy orientation of the needle with the patient and providing the user with a guide for actuation and engagement with the hinged shield.  
           [0020]    The assembly of the present invention may further comprise means for minimizing exposure by the user to residual fluid leaking from a used needle. For example, a polymer material, such as a gel, may be located in the hinged shield.  
           [0021]    Most desirably, the assembly of the present invention is such that the cooperating parts of the assembly provide the means for the hinged shield to move into a forward position over the needle. Thus, by simple movement of the hinged shield into a forward position over the used needle, the assembly is ready for subsequent disposal. Therefore, the assembly of the present invention provides minimal exposure of the user to a needle because the shielding is initiated by the user immediately after the needle is withdrawn from the patient&#39;s vein.  
           [0022]    Desirably, the assembly of the present invention may be used with a syringe assembly, a hypodermic needle, a needle assembly, a needle assembly with a needle holder, a blood collection set, an intravenous infusion set or other fluid handling devices. Preferably, the assembly of the present invention is used with a needle assembly comprising a needle and a hub. Preferably the needle is a conventional double ended needle.  
           [0023]    Most preferably, the present invention is used with a needle assembly comprising a hub and a needle connected to the hub whereby the needle comprises a non-patient end and an intravenous end. The collar of the present invention may comprise a hook arm and the hinged shield may be connected movably to the hook arm. Thus the hinged shield may be positioned with respect to the collar and moved easily into several positions.  
           [0024]    Preferably, the collar is fitted non-rotatably with the hub of the needle assembly. Additionally, the collar includes cooperating means that mate with reciprocal means on the shield to provide a clear audible and tactile indication of shielding. The cooperating means on the collar may include generally chevron-shaped projection formed on a side of the collar substantially diametrically opposite the hook arm or other such structure that provides the hinge connection to the shield. The chevron-shaped structure includes a forward or distal point. Slanting surfaces diverge and extend proximally from the distal point. The slanting surfaces cooperate with the reciprocal means on the shield to generate a deflection of the sidewalls of the shield away from one another. The chevron-shaped structure further includes proximal ends that are convexly arcuate. The convexly arcuate ends of the chevron-shaped structure on the collar cooperate with the reciprocal means on the shield and with the resiliently deflectable sidewalls of the shield to generate the tactile and audible indication of shielding.  
           [0025]    The hinged shield preferably includes at least one cannula finger lock for locked engagement with the cannula when the hinged shield is in the second position around the needle cannula. The cannula finger lock preferably projects obliquely from one sidewall of the hinged shield angularly toward the opposed sidewall and the top wall of the shield. The cannula finger lock is dimensioned, disposed and aligned to contact the needle cannula when the hinged shield approaches the second position. Contact between the cannula and the cannula finger lock will cause the cannula finger lock to resiliently deflect toward the sidewall from which the cannula finger lock extends. Sufficient rotation of the hinged shield will cause the needle cannula to pass the cannula finger lock. As a result, the cannula finger lock will resiliently return to or toward its undeflected condition for securely trapping the needle cannula in the hinged shield.  
           [0026]    Preferably, the collar is fitted with the hub of the needle assembly so that the collar cannot rotate around the hub.  
           [0027]    Alternatively, the collar and hub may be a unitary one-piece structure. The one piece structure may be accomplished by many methods including molding the collar and the hub as a one-piece unit thereby eliminating the need to separately assemble the collar to the hub during the manufacturing process.  
           [0028]    Most preferably, the collar is fitted with the hub of the needle assembly so that the bevel surface or bevel up surface of the intravenous or distal end of the needle faces the same side of the collar when the hinged shield is in the open position. Alignment of the collar, hub, hinged shield and needle with the bevel surface up makes it easier to insert the needle into the patient without manipulating the assembly. The orientation of the intravenous end of the needle with the bevel up assures the user that the needle is properly oriented for use and does not require any manipulation before use. Most notably, the orientation of the hinged shield provides a visual indication to the user of the orientation of the bevel surface of the needle.  
           [0029]    Preferably, the hinged shield is capable of pivoting from a first position, where the intravenous end of the needle is exposed and bevel up, to an intermediate position where the needle is partially covered, to a second position where the needle is contained by the shield.  
           [0030]    Alternatively, it is within the purview of the present invention that the hinged shield, collar and hub is a unitary one-piece structure. The one-piece structure may be accomplished by many methods including molding the hinged shield, collar and hub as a one-piece unit thereby eliminating the need to separately assemble the hinged shield, collar and hub during the manufacturing process.  
           [0031]    It is an advantage of the present invention that the hinged shield covering the used intravenous end of the needle provides easy containment of the used needle. A further advantage of the hinged shield is that it will only move upon initiation by the user.  
           [0032]    The assembly of the present invention when used with a fluid handling device is also easily disposable when removed from a conventional needle holder, or other such device.  
           [0033]    A notable attribute of the present invention is that it is easily adaptable with many devices. For example, the invention is usable with syringe assemblies, hypodermic needles, needle holders, blood collection needles, blood collection sets, intravenous infusion sets such as catheters or other fluid handling devices or assemblies that contain piercing elements.  
           [0034]    Another notable attribute of the present invention is that the tactile and visual features deter the user from touching the needle, allow the user to easily orient the needle with the patient and guide the user to actuate and engage the shield of the assembly. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0035]    [0035]FIG. 1 is a perspective view of the safety shield assembly of the present invention as connected to a needle assembly and related packaging features.  
         [0036]    [0036]FIG. 2 is a perspective view of the unassembled pieces of FIG. 1.  
         [0037]    [0037]FIGS. 3A and 3B are bottom views of the shield as shown in FIG. 2.  
         [0038]    [0038]FIG. 4 is a cross sectional view of the collar as shown in of FIG. 2 taken along lines  4 - 4  thereof.  
         [0039]    [0039]FIG. 5 is a cross sectional view of the needle hub as shown in FIG. 2 taken along lines  5 - 5  thereof.  
         [0040]    [0040]FIG. 6 is a cross sectional view of the shield of FIG. 2 taken along lines  6 - 6  thereof.  
         [0041]    FIGS.  7 - 12  illustrate the use of the safety shield assembly with the needle assembly of FIG. 1 with a conventional needle holder.  
         [0042]    [0042]FIG. 13 is a cross sectional view of the assemblies in use with a conventional needle holder as shown in FIG. 12 taken along lines  13 - 13  thereof.  
         [0043]    [0043]FIG. 14 is a cross-sectional view of the assemblies of FIG. 13 taken along lines  14 - 14  thereof.  
         [0044]    [0044]FIG. 15 is a bottom view of the assemblies as shown in FIG. 11.  
         [0045]    [0045]FIG. 16 illustrates an additional embodiment of the present invention, whereby a gel material is located in the shield as shown in a bottom view of the assemblies of FIG. 11.  
         [0046]    [0046]FIG. 17 is a perspective view of an additional embodiment of the present invention in use with a blood collection set.  
         [0047]    [0047]FIG. 18A is an exploded perspective view of an additional embodiment of the present invention intended for use with a syringe.  
         [0048]    [0048]FIG. 18B is a perspective view of the collar of the embodiment of FIG. 18A.  
         [0049]    [0049]FIG. 18C is a side elevational view of the embodiment of FIG. 18A mounted to a syringe.  
         [0050]    [0050]FIG. 19 is a perspective view of an additional embodiment of the present invention in use with a catheter. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0051]    While this invention is satisfied by embodiments in many different forms, there is shown in the drawings and will herein be described in detail, the preferred embodiments of the invention, with the understanding that the present disclosure is to be considered as exemplary of the principles of the invention and is not intended to limit the invention to the embodiments illustrated. Various other modifications will be apparent to and readily made by those skilled in the art without departing from the scope and spirit of the invention. The scope of the invention will be measured by the appended claims and their equivalents.  
         [0052]    Referring to the drawings in which like reference characters refer to like parts throughout the several views thereof, FIGS. 1 and 2 illustrate a needle assembly with the safety shield assembly of the present invention and the related packaging features. The needle assembly includes a needle  40 , a hub  60 , packaging features to cover the needle and a label. The safety shield assembly includes a collar  90  and a hinged shield  140 .  
         [0053]    As shown in FIGS. 2 and 5, needle  40  includes a non-patient end  42 , an intravenous end  44  and a passageway  46  extending between the non-patient end and the intravenous end. An elastomeric sleeve  48  covers the non-patient end. A first rigid sleeve  50  covers the intravenous end and a second rigid sleeve  52  covers both the non-patient end and the elastomeric sleeve. As shown in FIG. 1, a label  196  may also be applied to the finally assembled parts. First rigid sleeve  50  includes a rigid tubular sidewall  53  with an open proximal end  54  and a closed distal end  55 . An array of external threads  56  extends around first rigid sleeve  50  adjacent proximal end  54 .  
         [0054]    As shown in FIGS. 2 and 5, hub  60  includes a threaded end  64 , a ribbed end  66  and passageway  62  extending between the threaded end and the ribbed end. Threaded end  64  and ribbed end  66  are separated by flange  68 . Non-patient end  42  of needle  40  extends from threaded end  64  and intravenous end  44  of needle  40  extends from ribbed end  66 . Preferably, threaded end  64  comprises male threads  80  for mounting the hub on a conventional needle holder and ribbed end  66  comprises male ribs  82  for connecting the hub and collar  90 .  
         [0055]    As shown in FIGS. 2 and 4, collar  90  includes a forward skirt  92  and a rearward skirt  94 . Forward skirt  92  is cylindrical and comprises an inner circumferential surface  96  with an array of internal threads  97  and an outer circumferential surface  98 . Forward skirt  92  mates with rearward skirt  94  at a shoulder  100 . Rearward skirt  94  is cylindrical and comprises an inner circumferential surface  102  and an outer circumferential surface  104  and extends from shoulder  100  opposite of forward skirt  92 . The inner diameter of forward skirt  92  is larger than the inner diameter of rearward skirt  94 . Alternatively, the inner diameters for collar  90  can be equal. A hook  114  extends from outer circumferential surface  98  of forward skirt  92 . Additionally a chevron-shaped protrusion  118  projects outwardly from outer circumferential surface  98  of forward skirt  92  at a side opposite hook  114 . The chevron-shape protrusion  118  is substantially symmetrically formed and has a peak  120  pointed toward forward skirt  92  and ramp surfaces  122  that diverge symmetrically from peak  120  toward rearward skirt  94 . Ramp surfaces  122  terminate at rounded ends  124  at the outer side and proximal extremes of chevron-shaped protrusion  118 . Rounded ends  124  extend continuously into the proximal side of chevron-shaped protrusion  118  facing toward rearward skirt  94 .  
         [0056]    As shown in FIGS. 2 and 6, hinged shield  140  comprises a rearward end  144  and a forward end  146 .  
         [0057]    Forward end  146  of hinged shield  140  includes a slot or longitudinal opening  160  formed by sidewalls  162  that extend downwardly from top wall  163  and run substantially opposite of one another in parallel along the length of slot  160  towards forward end wall  164 . Slot  160  is slightly wider than needle  40 . Sidewalls  162  include bottom edges  165  that extend substantially parallel to one another and parallel to top wall  163 .  
         [0058]    A cannula finger lock  167  is located at one of sidewalls  162  and is configured to secure the used needle. Cannula finger lock  167  extends from a location on a first of the sidewalls  162  adjacent the bottom edge  165  thereof and projects angularly toward the opposed sidewall  162  and toward the top wall  163 . The projection of the cannula finger lock  167  from the respective sidewall  162  preferably exceeds half the distance between the respective sidewalls. Cannula finger lock  167  is deflectable by the needle when the needle enters slot  160 . Once the needle passes the end of cannula finger lock  167 , the cannula finger lock moves back to its original position so that the needle is permanently trapped in slot  160  by cannula finger lock  167 .  
         [0059]    Rearward end  144  of hinged shield  140  defines a collar engaging area  166  that is a continuation of slot  160 . Collar engaging area  166  includes a rearward end  168 , a forward end  170 , a top finger guide area  172 , sidewalls  174  that extend downwardly from top finger guide area  172 , an underside area  176  dimensioned for surrounding collar  90 , and extending arms  180  to support and hold hanger bar  182 . Sidewalls  174  are spaced apart by a major width adjacent rearward end  168 . The major width is selected to enable sidewalls  174  to slide across diametrically opposite side surfaces of forward skirt  92  of collar  90 . Sidewalls  174  converge, however, toward forward end  170  to define a minor distance therebetween substantially equal to the distance between sidewalls  162  at forward end  146  of hinged shield  140 . Sidewalls  174  include bottom edges  177  that face away from top finger guide area  172 . As shown most clearly in FIG. 6, bottom edges  177  curve toward top finger guide area  172  at locations between rearward end  168  and forward end  170  of collar engaging area  166 .  
         [0060]    The extreme rear ends of sidewalls  174  on collar engaging area  166  include rounded ears  194  that project toward one another from opposed inner surfaces  175  of sidewalls  174 . Rounded ears  194  are disposed to engage chevron-shaped protrusion  118  on collar  90 . More particularly, each rounded ear  194  includes a distal surface  195 , a proximal surface  197  and a curved surface  198  extending between distal and proximal surfaces  195  and  197 . Distal surface  194  is aligned to sidewall  174  at an angle of approximately 60° and proximal surface  197  is aligned to sidewall  174  at an angle of approximately 45°. Curved surface  198  extends smoothly and convexly between distal and proximal surfaces  195  and  197 . Proximal surfaces  197  of rounded ears  194  will engage ramp surfaces  122  of chevron-shaped protrusion  118  to deflect sidewalls  174  slightly away from one another as hinged shield  140  approaches the second position. This deflection of sidewalls  174  will occur substantially simultaneously with the deflection of cannula finger lock  167 . The apex of curved surface  198  on each rounded ear  194  passes the respective rounded proximal end surface  124  on chevron-shaped projection  118  on collar  90  slightly before cannula finger lock  167  passes the needle cannula. As a result, sidewalls  174  begin to return resiliently toward an undeflected condition. This resilient return of sidewalls  174  cooperates with raked distal surfaces  195  on rounded ears  194  to cause sidewalls  174  to snap against chevron-shaped projection  118 . This snapping action provides a clear audible and tactile indication of complete shielding and occurs substantially when the used needle is trapped by cannula finger lock  167 . The angles of distal and proximal surfaces  195  and  197  of rounded ears  194  affects the performance of hinged shield  140 . In particular, a smaller acute angle alignment of proximal face  197  reduces the force required to move hinged shield  140  past rounded ears  194 . A larger acute angle proximal surface  197  of rounded ears  194  requires a greater force to move hinged shield  140  toward the second position. Similarly, the angle between distal surface  195  and sidewall  174  affects the acceleration characteristics as hinged shield  140  is propelled toward the second position in response to the resilient return of sidewalls  174 . This change in acceleration characteristics affects the audible indication of shielding.  
         [0061]    Top finger guide area  172  comprises a first ramp  184  that extends slightly on an upwardly slope from the rearward end of the collar engaging area to a shoulder  186 . From shoulder  186  extends a second ramp  188  which slopes downwardly towards top section  163 . Most preferably, first ramp  184  comprises touch bumps  190 . The touch bumps provide a tactile and visual guide to alert the user that the user&#39;s finger has contacted the shield and that the shield is in a defined or controlled position. The touch bumps may be any configuration so long as they extend and are distinct from the top finger guide area. The touch bumps may also be of a distinguishing color as compared to the top finger guide area or the shield.  
         [0062]    Second ramp  188  has interior surface  192  for urging the needle toward the center of slot  160  as the shield is being rotated into the closed position. The exterior surfaces are slightly inclined and extending radially from the second ramp. The interior surfaces are especially helpful if the longitudinal axis of the needle is misaligned with respect to the longitudinal axis of the hub.  
         [0063]    Extending arms  180  are located at rearward end  168  and at the beginning of top finger area  172  and hold hanger bar  182 .  
         [0064]    The safety shield assembly and the needle assembly are assembled together whereby needle  40  is connected to hub  60  and sealed with adhesive at the ends of the hub. Hub  60  then is joined with collar  90  by ultra-sonic welding techniques or any other bonding techniques, or mechanical fit, whereby rearward annular skirt  94  of collar  90  mates with ribbed end  66  of the hub. Male ribs  82  of the hub are contained or forced fitted within inner sidewall  102  of rearward annular skirt  94  of collar  90 . Collar  90  is aligned with the intravenous end of needle  40  whereby the hook  114  is aligned with the bevel up of needle  40 . External threads  96  adjacent proximal end  54  of first rigid sleeve  50  then are threaded into engagement with internal threads  97  formed on inner circumferential surface  96  of forward skirt  92  of collar  90  to cover needle  40 . Thereafter, hinged shield  140  is connected to collar  90  whereby hanger bar  182  is force fitted into hook  114  whereby slot  160  faces first rigid sleeve  50 . Most preferably, hinged shield  140  is connected to the collar by a force fit or interference fit between hanger bar  182  and hook  114 . Therefore, hinged shield  140  is always oriented in a stable position and will not move unless movement of the shield is positively initiated by the user. To assemble the last piece, shield  140  is moved towards rigid sleeve  50  and second rigid sleeve  52  is force fitted onto outer sidewall  104  of rearward skirt  94  of collar  90 .  
         [0065]    In addition, a label  196  may be applied to the finally assembled parts. The label may be used to provide tamper resistance of the parts, so that they are not reused.  
         [0066]    In use, as shown in FIGS.  7 - 15 , second rigid sleeve  52  is removed from the non-patient needle by pulling proximally on second rigid sleeve  52 . A slight twisting force may be required to tear label  196 . A needle holder then is screwed onto threads  64  of hub  60 . As specifically shown in FIGS. 9 and 10, hinged shield  140  then is rotated back by the user towards the needle holder and first rigid sleeve  50  is threadedly disengaged from forward skirt  92  of collar  90  to remove the covering from the intravenous needle. Then as shown in FIG. 11, a venipuncture is conducted whereby the intravenous end of the needle is inserted into a vein of a patient and an evacuated tube having a closure is inserted into the needle holder. Then as shown in FIGS.  12 - 15 , when the venipuncture is complete the user easily rotates hinged shield  140  from the open position towards the intravenous needle to an intermediate position and then the user pushes on the shield at the top finger guide area to move the shield into a second position whereby the needle is trapped in the longitudinal opening. More particularly, needle  40  contacts cannula finger lock  167 . The engagement of needle  40  with cannula finger lock  167  causes cannula finger lock  167  to deflect toward top wall and toward the sidewall  162  from which cannula finger lock  167  projects. Sufficient rotation of hinged shield  140  will cause needle  40  to pass cannula finger lock  167 . As a result, cannula finger lock  167  will return resiliently to an undeflected condition. Thus, needle  40  will be trapped above cannula finger lock  167 .  
         [0067]    Needle  44  is contained within hinged shield  140  as the shield is pivoted into the second position. More particularly, proximal surfaces  197  of rounded ears  194  move over detents  118  and cause sidewalls  174  to deflect away from one another. The angularly aligned proximal faces  197  of rounded ears  194  ensure easy movement of shield  140 . Additionally, the resiliency of sidewalls  174  and the angular alignment of distal surface  195  of ears  194  causes hinged shield  140  to be accelerated into the second position. This accelerated movement of shield  140  helps to generate a clear audible and tactile indication of shielding.  
         [0068]    Alternatively as shown in FIG. 16, a gel material  190  is located in hinged shield  140  so that when the needle snaps past cannula finger lock  167  it will come to rest in gel material  190 . The gel material will contain any residual fluid that may be on the needle. Simultaneously, rounded ears or projections  198  move over detents  118 . This causes sidewalls  174  to deflect away from one another and then to snap back into engagement with collar  90  to provide a clear audible and tactile indication of complete shielding.  
         [0069]    FIGS.  17 ,  18 A-C, and  19  are further embodiments of the invention that may include components which are substantially identical to the components of FIGS.  1 - 3 . Accordingly, similar components performing similar functions will be numbered identically to those components of FIGS.  1 - 3 , except that a suffix “a” will be used to identify those similar components in FIG. 17, a suffix “b” will be used to identify those similar components in FIGS.  18 A-C and a suffix “c” will be used to identify those similar components in FIG. 19.  
         [0070]    For purposes of illustration, hinged shield  140   a  and collar  90   a  are connected to a conventional IV infusion set,  200 , or butterfly structure comprising a needle body with a needle hub  204  extending from the forward end of the needle body and a needle  206  embedded in hub  204 . Extending from the rearward end of the needle body is flexible tubing  208  which is conventional and utilized to allow the user to manipulate the structure and to connect it subsequently to supplies of infusion liquids or for the return of collected blood if the arrangement is being used to collect blood.  
         [0071]    Infusion set  200  further comprises flexible wings  210  attached to and projecting outwardly from needle hub  204 .  
         [0072]    Alternatively, the safety shield assembly of the present invention may be used in conjunction with a syringe, as illustrated in FIGS.  18 A-C.  
         [0073]    For purposes of illustration a conventional hypodermic syringe  300  comprises a syringe barrel  302  having a distal end  304 , a proximal end  306  and a plunger  312 . In this embodiment, a needle assembly  314  includes a hub  316  with a proximal end  318  that defines a female Luer fitting that can be mate with distal end  304  of syringe barrel  302 . An intravenous needle  320  projects distally from hub  316 . A collar  322  is mounted rigidly to hub  316  and includes a hook  324  at a location aligned substantially with the bevel up side of intravenous needle  320 . Alternatively, collar  322  and hub  316  may be a single component. A shield  326  is hingedly mounted to hook  324 . Collar  322  and hinged shield  326  are substantially identical to embodiments described and illustrated in greater detail above. In particular, collar  322  is provided with an array of internal threads  328 , as shown in FIG. 18B.  
         [0074]    Pre-use sterility and safety are maintained by an end cap  330  and an IV shield  332 . End cap  330  includes a male Luer projection  334  and an outer collar  336 . Male Luer projection  334  is dimensioned to be frictionally retained within female Luer fitting at proximal end  318  of hub  316 . Outer collar  336  is dimensioned to be frictionally retained around hub  316 . End cap  330  can be removed from hub  316  with an exertion of proximally directed axially forces that may be combined with a slight rotational twisting force relative to hub  316 . End cap  330  prevents contamination of interior portions of hub  316 , and hence also prevents contamination of the lumen through intravenous needle  320 . IV shield  332  comprises a rigid generally tubular sidewall  340  with a proximal end  342  and a closed distal end  344 . Outer surface regions of IV shield  332  adjacent proximal end  342  define an array of external threads  346  that are dimensioned for threaded engagement with internal threads  328  on collar  322 . Thus, the IV shield can be threadedly mounted to collar  322  for protectively covering IV needle  320  and further contributing to sterility of IV needle  320 .  
         [0075]    Prior to use, end cap  330  is mounted frictionally over proximal portions of needle hub  316  and IV shield  332  is mounted threadedly to internal threads  328  of collar  322  and over intravenous needle  320 . Hinged shield  326  then is rotated into a partly closed condition where proximal portions of hinged shield  322  partly surround and frictionally engage portions of IV shield  322  distally of and adjacent to external threads  346 .  
         [0076]    The needle assembly is used by initially separating end cap  330  from needle hub  316 . Threaded engagement of IV shield  332  ensures that IV shield  332  will not inadvertently become separated from collar  322  in response to axial pulling forces exerted on end cap  330 . Thus, IV needle  320  remains safely covered and protected. Proximal end  318  of needle hub  316  then is mounted to distal end  304  of syringe  300 . IV shield  332  must be removed to access needle  320  and to use syringe  300 . The removal of IV shield  332  requires the disengagement of external threads  346  on IV shield  332  from internal threads  328  on collar  322 . However, the initial disposition of hinged shield  326  partly surrounding and adjacent IV shield  332  substantially prevents IV shield  332  from being threadedly disengaged from collar  322  without first rotating hinged shield  326  away from IV shield  332  and into the ready-to-use position. Thus, the user must follow the preferred practice of rotating hinged shield  326  away from needle cannula  320  and into the ready-to-use position prior to threadedly disengaging IV shield  332 . Accordingly, the needle assembly of FIGS.  18 A-C substantially prevents the less safe practice of first removing IV shield  332  to expose needle  320  and then manually moving hinged shield  326  while the intravenous needle  320  is exposed. Furthermore, the needle assembly shown in FIGS.  18 A-C ensures that the end cap  330  will be removed before exposing needle  320 . Accordingly, hub  316  is likely to be threadedly engaged with syringe  300  before rotating hinged shield  326  into the ready-to-use position and before separating IV shield  332 . FIGS.  18 A-C show a threaded connection between IV shield  332  and collar  322 . However, other attachment mechanisms can be provided between IV shield  332  and collar  322  that would make separation difficult while hinged shield  326  is in partly surrounding disposition to IV shield  332 . For example, detents can be provided between IV shield  332  and collar  322  that would make simple pulling of IV shield  332  away from collar  322  difficult. The detent may require some rotational movement of IV shield relative to collar  322  to overcome frictional interference. Other such connections that would require secure gripping of IV shield  332  and/or twisting of IV shield  332  to effect removal may be provided.  
         [0077]    Alternatively, the present invention may be used in conjunction with a catheter as illustrated in FIG. 19.  
         [0078]    The shield and collar of the safety shield assembly of the present invention are comprised of moldable parts which can be mass produced from a variety of materials including, for example, polyethylene, polyvinyl chloride, polystyrene or polyethylene and the like. Materials will be selected which will provide the proper covering and support for the structure of the invention in its use, but which will provide also a degree of resiliency for the purpose of providing the cooperative movement relative to the shield and the collar of the assembly.  
         [0079]    The illustrated embodiments show the first rigid sleeve or IV shield with external threads and the hub with the mating internal threads. However, the relative disposition of the internal and external threads may be reversed.  
         [0080]    The illustrated embodiments show a cannula finger lock for engaging the needle. However, other means may be provided for maintaining the hinged shield around the needle, including more than one cannula finger lock or differently configured needle engaging structures.