Patent Publication Number: US-2004049155-A1

Title: Needle tip protector

Description:
[0001] This application claims the benefit under 35 U.S.C. 119(e) of the filing date of provisional application Ser. No. 60/366,947, filed Jun. 6, 2002. 
    
    
     
       BACKGROUND OF THE INVENTION  
       [0002] 1. Field of the Invention  
       [0003] The present invention relates in general to devices for covering and guarding the tip of a needle or other sharp medical instrument after use and, more particularly, to a needle tip guard which locks into place over the tip of a sharp needle after the needle has been used to prevent accidental puncture or reuse.  
       [0004] 2. Background Art  
       [0005] Devices designed to protect the typically sharp tip of a needle have been known in the art for many years. In particular, given the wide concern regarding AIDS and other diseases that are carried in human blood and transmitted through the bloodstream, it has been highly desirable to provide protectors or guards to cover the tip of hypodermic needles, catheters, or other sharp medical needle-type devices after those devices have been used. Needle tip guards have been designed to fit over the tip of the needle after the needle has been used, to both guard against subsequent use, as well as to prevent inadvertent puncture. Reuse can result when used hypodermic or other needles are thrown into a garbage receptacle or recycling receptacle and subsequently recovered for unintended or illegal use. Likewise, spent needles in a disposable container may inadvertently puncture or penetrate a person reaching into such as container to dispose of used needles or other waste.  
       [0006] Needle safety technology has become even more prevalent in recent years as many states have passed needle safety laws with specific guidelines for sharps needle protection technology. In particular, those laws have specified that all sharp needle tips used in medical applications require some form of needle tip guard to prevent inadvertent injury and puncture by the needle tip, as well as to eliminate subsequent reuse of already used needles. Reuse is a particularly strong concern as illegal drug use often occurs with used needles.  
       [0007] In response to the used needle problems discussed above, as well as the recent legislation, there have been a number of needle guard products designed specifically to offer sharps protection by locking over the tip of a needle, after use of the needle. Several of those needle guards, including those shown and described in Kulli, U.S. Pat. No. 4,929,241; Chamuel, U.S. Pat. No. 5,053,017; Sircom, et al., U.S. Pat. No. 5,322,517; Sircom, U.S. Patent No. 5,662,610; and Caizza et al., U.S. Pat. No. 5,910,130, have taken a form of needle guards which are mounted and slide on the shaft of a needle. In particular, these guards include a locking latch or jaw-like mechanism that covers the tip of the needle when the needle guard is slid past the needle tip.  
       [0008] Kulli, U.S. Pat. No. 4,929,241, discloses a protective guard formed as a single, unitary clip which rides on the shaft of a needle. The protective guard includes a base portion and a pair of flexible jaws which extend directly from and distally away from the base portion. The base portion includes an aperture for mounting the needle, through which aperture the shaft of the needle is received. The flexible jaws are biased to converge toward one another, and each jaw has a shield portion extending substantially transversely to the portion of the jaw which extends along the needle shaft. The ends of each transverse shield portion directly contacts the shaft of the needle before deployment of the device. The edges of each of the shields may be provided with an arcuate, even semi-circular groove, for engaging the sides of the needle shaft, when the clip is in its undeployed orientation (i.e., when the needle tip is still exposed). The flexible jaws also include sharp blades which extend from opposing inner surfaces of the flexible jaws at locations between the base and the transverse shields. The blades do not contact the sides of the shaft until the needle has been withdrawn from between the shield edges, thus deploying the protective guard and enabling the legs to move toward one another and the shields to overlap, covering the tip of the needle. The edges of the blades thus engage the sides of the needle shaft, toward preventing the needle shaft from being completely withdrawn from the guard.  
       [0009] Chamuel, U.S. Pat No. 5,053,017 discloses yet another needle tip guard, in the style of a clip, formed, in a basic embodiment, from a single, unitary convoluted strip of metal or other flexible material. The guard includes a base portion and two legs extending distally therefrom, one leg extending along and adjacent to the top portion of the needle and the other leg extending along and adjacent to the bottom portion of the needle. The bottom leg has a guide portion to assist in slidably maintaining the guard on the needle shaft. The upper leg includes a needle shaft engaging end portion and an inwardly folded bight which is configured to frictionally engage the side of the needle shaft, once the point of the needle has been pulled from between the free ends of the strip. The ends of the legs are biased to retain the needle shaft between the ends of the strip prior to deployment, but to overlap one another upon retraction of the needle tip past the end portion of the upper leg. The base portion includes an aperture through which the needle passes prior to passing between the otherwise overlapping ends of the strip. The area around the aperture is likewise configured to deform and frictionally engage the needle upon deployment of the device. Additional embodiments of the Chamuel &#39;017 reference employ biased rocking members which pivot, once the tip of the needle has been slid past a certain location, to block the re-emergence of the point, as well as to cause gripping engagement of the shaft of the needle.  
       [0010] The Sircom &#39;517 and &#39;610 references each disclose an independently spring biased, U-shaped latching member which is housed within a needle guard, and which is prompted over the needle tip after the needle tip is withdrawn past the latching member and into the needle guard. In one embodiment, the latching member includes a locking base plate (the longer leg of the “U”), a lever arm and a shield (the shorter leg of the “U”). The locking base plate includes an aperture through which the needle slides, which aperture digs into the shaft of needle upon canting of the latching member. The shield contacts the needle before retraction of the needle into the housing and deployment of the latching member. The housing further includes the spring biasing member which bears against the latching member to cant the latching member about a pivot point formed between the lever arm and the inner surface of the housing, upon retraction of the needle tip past the shield. Thus, upon deployment, the latching member prevents movement of the needle back out of the guard, while also digging into the shaft of the needle to resist movement of the needle guard off of the needle.  
       [0011] Other embodiments of these patents employ outer shells, through which the needles pass, when the needles are in their usable positions. Upon pulling the needle tips into the housings, the needles unobstruct various structures which are then permitted to pivot, under coil spring biasing, into positions in which the needle tips are precluded from exiting back through the fronts of the housings. Various clutching mechanisms are also disclosed for frictionally engaging the sides of the needle shaft, once the tip of the needle has been withdrawn into the housing.  
       [0012] Caizza, U.S. Pat. No. 5,910,130, discloses a needle guard in the form of a housing, through which the needle shaft passes. A sigma-shaped unitary spring clip is mounted within the housing, with the shaft passing through an aperture in one foot of the sigma, and the edge of the other foot of the sigma bearing against the side of the shaft. When the needle shaft is withdrawn, the spring foot of the shaft moves across and block the path of the needle tip. The reference also discloses a form of levered mechanism for moving the housing along the needle shaft, without bringing the user&#39;s fingers into the vicinity of the needle tip.  
       [0013] In use of these devices, the needle guard is first mounted onto the base of the needle shaft before the needle is used. Then, after the needle has been used, the guard is slid away from the base of the needle, toward the distal end of the needle and over the tip of the needle. Once the guard advances past the needle tip, it automatically locks into place on the distal end of the needle shaft, thus anchoring on the distal end of the needle and acting as a shield over the needle tip.  
       [0014] While these and other needle guards have worked well to prevent injury and reuse of hypodermic needles and other sharp-tipped medical devices, these prior art devices have been difficult to mount onto a given needle, without damaging the needle tip. In particular, mounting the needle guards over sharp needle tips may lead to needle puncture or other injury, particularly if the needle guards are placed on the needle shaft without proper instructions or mounting equipment. Accordingly, these needle guards typically must be mounted to the corresponding needle, catheter or other medical device by the manufacturer, thus preventing application of these needle guards to needles, catheters and other medical devices originally unadorned with a needle guard. It is believed that needle-type devices are still manufactured and sold without a needle guard.  
       [0015] It is thus desirable to provide a needle protector or guard which may be easily mounted onto the shaft of a hypodermic needle or other sharp catheter, biopsy needle or other needle-type medical device to allow use of the needle protector or guard with a number of needle-type devices.  
       [0016] It is likewise desirable to allow mounting of the needle protector or guard onto a given needle with relative ease, to minimize the time it may take for a needle user to mount a needle protector or guard onto to base of a needle.  
       [0017] It is also desirable to provide a needle guard carrier which may be placed interchangeably onto different types of needles to ensure that a user is able to lock the needle protector or guard over the tip of the needle after use to prevent injury or reuse.  
       [0018] These and other desirable characteristics of the invention will become apparent in view of the present specification, including the claims, and drawings.  
       SUMMARY OF THE INVENTION  
       [0019] The present invention is directed in part to a needle tip guard for placement on the shaft of a hollow needle, for positioning over a tip region of the hollow needle, following completion of use of the hollow needle, for isolating the tip region of the hollow needle. The needle tip guard comprises, in part, a housing, operably configured to describe a void region and having a front end region and a rear end region. The housing has at least one passage therethrough operably configured to receive a shaft of a hollow needle therethrough. A resilient shield member is disposed within said void region within the housing and configured for movement between a first, undeployed position and a second deployed position, whereupon the positioning of a hollow needle shaft through the housing extending from the first end region to the second end region, the resilient shield member is retained in its first undeployed position, in a deformed configuration with a portion of the inserted hollow needle shaft preventing movement of the shield member into the deployed configuration; in which stored force in the deformed shield member, upon movement of an inserted hollow needle shaft relative to the housing such that a tip of the hollow needle shaft is received within the void region, prompts the shield member to reorient from the first position to the second deployed position. The resilient shield member, in the second deployed position, is disposed to simultaneously preclude re-emergence of a tip of the hollow needle shaft out from the front end region of the housing, and exert a restraining force against the hollow needle shaft toward inhibiting movement of the hollow needle shaft relative to the housing.  
       [0020] The needle tip guard may further comprise a needle shaft carrier, removably inserted into the housing, and extending from the front end region through to the rear end region thereof. The needle shaft carrier preferably has a hollow configuration with an inner passage which is configured to insertingly a hollow needle member, and is configured for facilitating insertion of a hollow needle shaft, and subsequent removal of the needle shaft guide member from the housing, prior to use of the hollow needle.  
       [0021] The shield member preferably has a first end and a second end, the first end having an aperture operably configured to receive a hollow needle shaft therethrough, the second end being disposed to bear against a side portion of a hollow needle shaft, when the shield member is in its first undeployed position. The second end is disposed in a path of movement of the hollow needle shaft, when the shield member is in its second deployed position, to preclude subsequent movement of a tip of the hollow needle shaft out of the front end region of the housing. The structure surrounding the aperture in the first end of the shield member is preferably operably configured to frictionally engage a hollow needle member extending therethrough, when the shield member is disposed in its second deployed position. The second end of the shield member is preferably configured as a straight edge region, configured to obliquely abut a side surface of a hollow needle shaft, when the shield member is in its first position. The second end of the shield member may alternatively be configured as a substantially U-shaped turned under region, a curved bight portion of which is configured to obliquely abut a side surface of a hollow needle shaft, when the shield member is in its second position.  
       [0022] The needle tip guard may further comprise an outer shell operably configured to enclose and receive the housing. At least one resilient attachment member may be disposed proximate the rear end region of the housing, with at least one attachment member engagement region disposed proximate a rear end region of the outer shell. Alternatively, at least one resilient attachment member may be disposed proximate the front end region of the housing and at least one attachment engagement region may be disposed proximate a front end region of the outer shell.  
       [0023] A guide lip, may be provided, extending from the second end of the shield member and disposed for sliding contact relative to a portion of the surface of a hollow needle member insertingly disposed within the housing, upon relative movement of the hollow needle member relative to the needle tip guard.  
       [0024] The shield member may have an end configured to bear against a side portion of a hollow needle shaft, when the shield member is in its first undeployed position. The end may be configured to move into a path of movement of the hollow needle shaft, when the shield member is in its second deployed position, to preclude subsequent movement of a tip of the hollow needle shaft out of the front end region of the housing. The void region within the housing may be defined in part by an interior forward wall, along which an end of the shield member is configured to slide. The interior forward wall may be straight. Alternatively, the interior forward wall has a first portion which is disposed at a first included angle, relative to the shaft of a hollow needle which has been inserted into the housing, which first portion is distal to the hollow needle shaft, and a second portion, proximate the hollow needle shaft, which is disposed at a second included angle, relative to the shaft of a hollow needle which has been inserted into the housing, which is less than the first included angle.  
       [0025] The invention is also directed in part to a needle tip guard for placement on the shaft of a hollow needle, for positioning over a tip region of the hollow needle, following completion of use of the hollow needle, for isolating the tip region of the hollow needle, wherein the needle tip guard comprises, in part, a housing, operably configured to describe a void region, and having a front end region and a rear end region. The housing has at least one passage therethrough operably configured to receive a shaft of a hollow needle therethrough. A support block has opposed first and second ends, and disposed within said void, and having a passage extending therethrough from the first end to the second end for receiving the shaft of a hollow needle. A shield member is disposed within the void and configured for pivotable movement within the void between an aligned configuration and an unaligned configuration. The shield member has a substantially rigid, C-shaped configuration, with first and second arm portions overlying the first and second ends of the support block, the first and second arm portions having apertures disposed therein, which align with the passage through the support block, when a hollow needle shaft is disposed in the passage and extending from the front end region through to the rear end region of the housing. A biasing member operably interconnects the shield member, the support block and the housing, for prompting the shield member from the aligned position to the unaligned position, upon withdrawal of a tip portion of the hollow needle shaft to a position within the void between the shield member and the support block. A clamp plate is operably associated with the shield member, for pivotable movement therewith, to frictionally engage the hollow needle shaft, upon movement of the shield member to the unaligned position, to resist withdrawal of the hollow needle shaft from the rear end region of the housing. The shield member, upon movement to the unaligned position, is disposed to preclude re-emergence of the tip portion of the hollow needle shaft from the front end region of the housing.  
       [0026] A needle shaft carrier may be removably inserted into the housing, and extending from the front end region through to the rear end region thereof, the needle shaft carrier having a hollow configuration with an inner passage which is configured to insertingly a hollow needle member. The needle shaft carrier is configured for facilitating insertion of a hollow needle shaft, and subsequent removal of the needle shaft guide member from the housing, prior to use of the hollow needle.  
       [0027] The present invention also comprises in part a needle tip guard for placement on the shaft of a hollow needle, for positioning over a tip region of the hollow needle, following completion of use of the hollow needle, for isolating the tip region of the hollow needle, wherein a housing is provided, operably configured to describe a void region, and having a front end region and a rear end region. The housing has at least one passage therethrough operably configured to receive a shaft of a hollow needle therethrough. A support block has opposed first and second ends, and disposed within said void, and having a passage extending therethrough from the first end to the second end for receiving the shaft of a hollow needle. A shield member is disposed within the void and configured for pivotable movement within the void between an aligned configuration and an unaligned configuration. The shield member has a substantially rigid, C-shaped configuration, with a planar web, and first and second arm portions extending therefrom, the first and second arm portions overlying the first and second ends of the support block, the first and second arm portions each having an aperture disposed therein, which apertures align with the passage through the support block, when a hollow needle shaft is disposed in the passage and extending from the front end region through to the rear end region of the housing. A biasing member operably interconnects the shield member, the support block and the housing, for prompting the shield member from the aligned position to the unaligned position, upon withdrawal of a tip portion of the hollow needle shaft to a position within the void between the shield member and the support block. The shield member, upon movement to the unaligned position, is disposed to preclude re-emergence of the tip portion of the hollow needle shaft from the front end region of the housing and to exert a resistive force against a side surface of the hollow needle shaft, toward inhibiting further movement of the hollow needle shaft relative to the needle tip guard.  
       [0028] The biasing member may comprise a spring member, mounted within the support block. Alternatively, the biasing member may comprise a spring member, mounted within the housing.  
       [0029] A needle shaft carrier may be removably inserted into the housing, and extending from the front end region through to the rear end region thereof, the needle shaft carrier having a hollow configuration with an inner passage which is configured to insertingly a hollow needle member. The needle shaft carrier is configured for facilitating insertion of a hollow needle shaft, and subsequent removal of the needle shaft guide member from the housing, prior to use of the hollow needle.  
       [0030] In another embodiment, the invention comprises a needle tip guard for placement on the shaft of a hollow needle, for positioning over a tip region of the hollow needle, following completion of use of the hollow needle, for isolating the tip region of the hollow needle, wherein a housing is operably configured to define a void region, and having a front end region and a rear end region, in which the housing has at least one passage therethrough operably configured to receive a shaft of a hollow needle therethrough. A shield member may be disposed within the void and configured for pivotable movement within the void between an aligned orientation permitting placement of a hollow needle shaft through the housing, and an unaligned orientation preventing passage of a hollow needle shaft through the front end region of the housing. An engagement member may be operably configured to be pivotable between a nonengagement position, when a hollow needle member is positioned in the housing extending from the front end region to the rear end region, and an engagement position, when a tip region of the hollow needle member has been withdrawn into the housing. The engagement member, in the nonengagement position permits the free movement of the hollow needle shaft relative to the housing, and in the engagement position exerting frictional force against the hollow needle shaft toward resisting movement of the hollow needle shaft relative to the housing. A biasing member, operably interengages the engagement member within the housing to prompt the engagement member toward the engagement position. An interconnecting member operably engages the engagement member with the shield member, and movable between a first position and a second position, wherein movement of the tip of the hollow needle shaft past the shield member, prompting the shield member to pivot, thus permitting the interconnecting member to move to a position permitting the engagement member to move to the engagement position.  
       [0031] A needle shaft carrier may be removably inserted into the housing, and extending from the front end region through to the rear end region thereof, the needle shaft carrier having a hollow configuration with an inner passage which is configured to insertingly a hollow needle member. The needle shaft carrier is preferably configured for facilitating insertion of a hollow needle shaft, and subsequent removal of the needle shaft guide member from the housing, prior to use of the hollow needle.  
       [0032] In yet another embodiment, the invention comprises a needle tip protector for placement on the shaft of a hollow needle, for positioning over a tip region of the hollow needle, following completion of use of the hollow needle, for isolating the tip region of the hollow needle, including a carrier including a substantially cylindrical tube having a hollow center, said cylindrical tube capable of being slidably mounted onto a needle. A needle guard is slidably mounted onto the carrier, such that the carrier and the needle guard may be simultaneously mounted onto the needle, but wherein the carrier may be removed from both the needle guard and the needle while leaving the needle guard slidably mounted on the needle. The needle guard preferably includes a locking shield which is prompted into a locking orientation covering the needle tip upon movement of the needle tip into the needle guard.  
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0033]FIG. 1 is a front elevation of the needle tip protector according to one embodiment of the invention.  
     [0034]FIG. 2 is a side elevation of the needle tip protector shown in FIG. 1.  
     [0035]FIG. 3 is a front elevation of the needle tip protector shown in FIG. 1 as mounted onto the base of a needle.  
     [0036]FIG. 4 is a front elevation in cross-section of the needle tip protector shown in FIG. 1 as mounted onto a portion of a needle, with the shield in a loaded position.  
     [0037]FIG. 5 is a front elevation view in cross-section of the needle tip protector shown in FIG. 1, with the shield deployed into a locking orientation over the tip of the needle.  
     [0038]FIG. 6 is a top plan view of the needle tip protector shown in FIG. 1.  
     [0039]FIG. 7 is a bottom plan view of the needle tip protector shown in  1 .  
     [0040]FIG. 8 a  is a side elevation, in section, of the shield shown in FIG. 4.  
     [0041]FIG. 8 b  is a bottom elevation of the shield shown in FIG. 4.  
     [0042]FIG. 8 c  is an end elevation of the shield shown in FIG. 4.  
     [0043]FIG. 9 a  is a side elevation, in section, of a shield according to an alternative embodiment of the invention.  
     [0044]FIG. 9 b  is a bottom elevation of the shield shown in FIG. 9 a.    
     [0045]FIG. 9 c  is an end elevation of the shield shown in FIGS. 9 a  and  9   b.    
     [0046]FIG. 10 a  is a side elevation of a housing for a needle guard according to an embodiment of the invention.  
     [0047]FIG. 10 b  is an end view of the needle guard housing according to the embodiment of FIG. 10 a.    
     [0048]FIG. 10 c  is a view from the other end of the needle guard housing according to the embodiment of FIG. 10 a.    
     [0049]FIG. 10 d  is a top view of the needle guard housing according to the embodiment of FIG. 10 a.    
     [0050]FIG. 10 e  is a bottom view of the needle guard housing according to the embodiment of FIG. 10 a.    
     [0051]FIG. 10 f  is a perspective view of an outer shell for use in combination with the needle guard housing of FIGS. 10 a - 10   e.    
     [0052]FIG. 11 a  is a side view of a needle guard housing according to an alternative embodiment of the invention.  
     [0053]FIG. 11 b  is an end view of the needle guard housing according to the embodiment of FIG. 11 a.    
     [0054]FIG. 11 c  is a bottom view of the needle guard housing according to the embodiment of FIG. 11 a.    
     [0055]FIG. 11 d  is a top view of the needle guard housing according to the embodiment of FIG. 11 a.    
     [0056]FIG. 12 a  is a schematic illustration of a needle tip guard, according to another alternative embodiment of the invention, shown with the needle in its “in use” position relative to the needle tip guard.  
     [0057]FIG. 12 b  is a schematic illustration of the needle tip guard according to the embodiment of FIG. 12 a , showing the needle tip in its retracted position, with the guard engaged.  
     [0058]FIG. 13 a  is a schematic illustration of a needle tip guard, according to another alternative embodiment of the invention, shown with the needle in its “in use” position relative to the needle tip guard.  
     [0059]FIG. 13 b  is a schematic illustration of the needle tip guard according to the embodiment of FIG. 13 a , showing the needle tip in its retracted position, with the guard engaged.  
     [0060]FIG. 14 a  is a plan view of a shield member, for use with the needle tip guard according to the embodiment of FIGS. 12 a  and  12   b.    
     [0061]FIG. 14 b  is a side elevation of the shield member of FIG. 14 a.    
     [0062]FIG. 15 a  is a plan view of a shield member, for use with the needle tip guard according to the embodiment of FIGS. 13 a  and  13   b.    
     [0063]FIG. 15 b  is a side elevation of the shield member of FIG. 15 a.    
     [0064]FIG. 16 a  is a side elevation of a needle tip guard according to an alternative embodiment of the invention.  
     [0065]FIG. 16 b  is a side elevation of the needle tip guard according to the embodiment of FIG. 16 a , wherein the outer shell is omitted to show the shield member in its undeployed position.  
     [0066]FIG. 16 c  is a side elevation of the needle tip guard according to the embodiment of FIG. 16 a , wherein the outer shell is omitted to show the shield member in its deployed position.  
     [0067]FIG. 16 d  is a side elevation, partially in section, of the needle tip guard according to the embodiment of FIG. 16 a , wherein the interaction between the outer shell and the barbs of the housing is shown.  
     [0068]FIG. 16 e  is a view of the needle tip guard, shown turned 90 degrees from the view of FIG. 16 a.    
     [0069]FIG. 17 a  is a side elevation of a needle tip guard according to an alternative embodiment of the invention.  
     [0070]FIG. 17 b  is a side elevation of the needle tip guard according to the embodiment of FIG. 17 a , wherein the outer shell is omitted to show the shield member in its undeployed position.  
     [0071]FIG. 17 c  is a side elevation of the needle tip guard according to the embodiment of FIG. 17 a , wherein the outer shell is omitted to show the shield member in its deployed position.  
     [0072]FIG. 17 d  is a side elevation, partially in section, of the needle tip guard according to the embodiment of FIG. 17 a , wherein the interaction between the outer shell and the barbs of the housing is shown.  
     [0073]FIG. 17 e  is a view of the needle tip guard, shown turned 90 degrees from the view of FIG. 17 a.    
     [0074]FIG. 18 a  is a side view of a needle tip guard according to another alternative embodiment of the invention, showing the guard with the outer shell omitted, to show an alternative shield member, in its undeployed position.  
     [0075]FIG. 18 b  is a side view of a needle guard according to the alternative embodiment of FIG. 18 a , showing the guard with the outer shell omitted, to show the alternative shield member in its deployed position.  
     [0076]FIG. 19 a  is a side elevation, of a needle guard according to a variation of the embodiment of FIGS. 16 a - 16   e , shown in its undeployed configuration.  
     [0077]FIG. 19 b  is a side elevation, of a needle guard according to a variation of the embodiment of FIGS. 16 a - 16   e , shown in its deployed configuration.  
     [0078]FIG. 19 c  is a side elevation, of a needle guard according to a variation of the embodiment of FIGS. 17 a - 17   e , shown in its undeployed configuration.  
     [0079]FIG. 19 d  is a side elevation, of a needle guard according to a variation of the embodiment of FIGS. 17 a - 17   e , shown in its deployed configuration.  
     [0080]FIG. 20 a  is a side view of a needle guard according to another alternative embodiment of the invention, showing the guard in its undeployed position.  
     [0081]FIG. 20 b  is a side view of the needle guard of the embodiment of FIG. 20 a , showing the guard in its deployed position.  
     [0082]FIG. 20 c  is a perspective view of the housing and moving components of the needle guard of FIGS. 20 a  and  20   b.    
     [0083]FIG. 21 a  is a side view of a needle guard according to another alternative embodiment of the invention, having an operation similar to that of the embodiment of FIGS. 20 a  and  20   b , and shown in its undeployed configuration.  
     [0084]FIG. 21 b  is a side elevation of the needle guard according to the embodiment of FIG. 21 a , shown in its deployed configuration.  
     [0085]FIG. 21 b  is a perspective, partially exploded, view of the housing, block, and pivoting member of the guard of FIG. 21 a.    
     [0086]FIG. 22 a  is a side view of a needle guard according to another alternative embodiment of the invention, having an operation similar to that of the embodiment of  
     [0087]FIGS. 21 a  and  21   b , and shown in its undeployed configuration.  
     [0088]FIG. 22 b  is a side elevation of the needle guard of FIG. 22 a , shown in its deployed configuration.  
     [0089]FIG. 22 c  is a perspective, partially exploded, view of the housing, block, and pivoting member of the guard of FIG. 22 a.    
     [0090]FIG. 23 a  is a side elevation of another needle tip guard according to another alternative embodiment of the invention, showing the guard in its undeployed configuration.  
     [0091]FIG. 23 b  is a side elevation of the needle tip guard of FIG. 23 a , showing it in its deployed configuration.  
     [0092]FIG. 23 c  is an exploded perspective view of the housing and principal moving components for the needle tip guard of FIGS. 23 a  and  23   b.    
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0093] While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will be described in detail several specific embodiments, with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated.  
     [0094] Needle tip guard  18  is shown in FIGS.  1 - 4  as including needle guard  20  and carrier (or loading tube)  22 . At the outset, it must be noted that while needle tip guard  18  will be shown as used in combination with a standard hypodermic needle  21 , it is contemplated that needle tip protector  18  may be used in combination with any number of medical needle-type devices. For instance, needle tip protector  18  may be used on hypodermic needles, biopsy needles, catheters, anesthesia needles, radiation needles mammography needles, etc. In essence, the needle tip protector is intended to be used in combination with any needle type device which includes a sharp tip which may be exposed after use of that needle type device. Further, while a specific needle tip protector is shown and described as used with a particular needle shape and diameter, it is contemplated that the needle tip protector may be used with various needles having any number of different shapes, diameters, lengths or tips.  
     [0095] Needle guard  20  is shown in FIGS.  1 - 7  as including housing  24 , spring  26  and shield  28 . Housing  24  is preferably constructed from a hard plastic material, while spring  26  and shield  28  are preferably constructed from a metallic material. However, it is certainly contemplated that alternative materials may be used in combination with the various components of the present invention. In addition, as shown in FIG. 3, an outer shell  27  is also provided, which is likewise preferably fabricated from a plastic material, although other materials may be employed, if desired. An analogous shell  27  is also shown in FIG. 10 f . Moreover, while needle guide  20  is shown in the drawings as having a substantially rectangular parallelepiped configuration with rounded corners, with the exception of the very top and bottom portions of the needle guard, others shapes are likewise contemplated. For instance, the needle guard may comprise a substantially oval shape, or substantially cylindrical shape with a relatively circular diameter. Any number of shapes would work well when used in combination with the present invention, as would be known by those with ordinary skill in the art having the present disclosure before them.  
     [0096] In an embodiment of the invention, housing  24  may be provided with resiliently disposed barbs  29 . Outer shell  27  may be a simple tube, having a rectangular cross-section (see, e.g., shell  27 ′ of FIG. 10 f ) which, once the internal components of guard  20  have been placed in housing  24 , can be slid onto and over housing  24 . Once barbs  29  have passed the edge of outer shell  29 , as seen in FIG. 3, they spring outwardly, and prevent outer shell  29  from being readily removed from housing  24 .  
     [0097] Making reference as well to FIGS.  4 - 7 , housing  24  includes spring cavity  30 , shield cavity  32 , top needle aperture  34  and bottom needle aperture  36 . Spring cavity  30  is preferably dimensioned to house spring  26 , and includes a seat  31  in which spring is retained. Shield cavity  32  is preferably a substantially inverted “L” shaped opening in housing  24 , taking an inverted L-shaped configuration as compared to L-shaped shield  28 . In particular, shield cavity  32  includes resting chamber  38 , namely an elongated vertical chamber, and a locking chamber  40 , which is designed to accept shield  28  in its locking position when needle guard  20  is moved past needle tip  23 . Shield cavity  32  allows spring  26  to cantilever shield  28  into the locking orientation when the needle tip is pulled into needle guard  20 .  
     [0098] Top needle aperture  34  and a bottom needle aperture  36  are formed in the top and bottom extension portions of needle guard  20 . Top needle aperture  34  and bottom needle aperture  36  are preferably aligned to accept cylindrically shaped carrier  22 , and to eventually, in turn, accept needle  21 . As will be described in more detail below, carrier  22  may be removed upon mounting of needle tip protector  18  to needle  21 , thus allowing positioning the needle shaft in top needle aperture  34  and bottom needle aperture  36 . The top and bottom apertures  34 ,  36 , are preferably only slightly larger in diameter than the carrier and needle, thus allowing a stable sliding movement of needle guard  20  back and forth along the needle shaft.  
     [0099] Shield  28  preferably includes bottom horizontal leg  42 , vertical leg  46  and upper horizontal leg  48 . Bottom horizontal leg  42  includes aperture  50  and spring contacting lip  52 . The diameter of aperture  50  is preferably only slightly larger than the diameter of carrier  22 , which is slightly larger than diameter of needle  21 , to help maintain shield  28  in a proper loaded, non-locking orientation, shown in FIG. 4. Aperture  50  in shield  28  also acts in combination with top needle aperture  34  and bottom needle aperture  36  in housing  24  to facilitate slidable movement of needle guard  20  on the needle shaft. Spring contacting lip  52 , shown in FIGS. 4, 5, and  8 , preferably contacts the bottom portion of spring  26 , such that spring  26  exerts a force on spring contacting lip  52 , and thus shield  28 . Bottom horizontal leg  42  is preferably in contact with housing  24 , specifically with the bottom portion of resting chamber  38 .  
     [0100] Vertical leg  46  spans the distance between bottom horizontal leg  42  and upper horizontal leg  48 . As can be seen in FIG. 4, a portion of vertical leg  46  preferably contacts the inner portion of housing  24 . However, it is likewise contemplated that no such contact is necessary.  
     [0101] Upper horizontal leg  48  includes needle riding lip  54 . As can be seen from FIG. 4, needle riding lip initially contacts carrier  22 , and then eventually needle  21  after carrier  22  is removed, as needle tip protector  18  is moved back and forth along the needle. The needle riding lip extends downwardly to provide the needle with a relatively flat bracing surface, which helps hold shield  28  into place before the needle withdrawn into needle guard  20  and shield  28  is deployed.  
     [0102] Alternatively, and as is shown in FIGS. 9 a - 9   c , an alternative shield  60  may employed, including upper horizontal leg  62  having no vertically extending lip. Accordingly, the end face of upper horizontal leg  62  would ride directly against carrier  22 , and then against needle  21  after removal of the carrier.  
     [0103] Carrier  22  is shown in FIGS.  1 - 4  as comprising a substantially hollow, cylindrical tube on which needle guard  20  is mounted, or more alternatively considered, carrier  22  has been inserted into needle guard  20 , prior to insertion of a needle. In particular, carrier  22  extends through top needle aperture  34 , bottom needle aperture  36 , as well as aperture  50  in shield  28 , and is slidably disposed relative thereto. Carrier  22  extends beyond the top and bottom portions of needle guard  20  so that a user may grasp either end of carrier  22 . The exact distance by which carrier  22  extends beyond the top and bottom portions of needle guard  20  may be varied, depending upon the particular application, user preference, etc. It is preferred, however, that carrier extends far enough on both sides of needle guard  20  such that a user can grasp carrier  22  to remove carrier from both needle guard  20 , as well as needle  21 .  
     [0104] Further, it is preferred that carrier  22  slides relatively freely within needle guard  20 , as well on needle  21 . As is the case with needle  21  when carrier  22  is removed from needle guard  20  and taken off of needle  21 , shield portion  28  of needle guard  20  helps maintain carrier  22  in a firm, friction-based contact with needle guard  20 . Further, it is preferred that the needle guard includes dulled or otherwise non-sharpened ends. This allows the advantageous placement of needle guard  20  onto carrier  22  without the risk of incurring an inadvertent carrier puncture wound during the mounting process, and especially without damaging the sharpened tip of the needle, which may otherwise occur, if an attempt is made to insert a needle through guard  20 , in the absence of carrier  22 .  
     [0105] In operation, and is best seen in FIGS.  1 - 5 , needle tip protector  18  including needle guard  20  mounted on carrier  22  is initially mounted on needle  21 . As is shown in FIG. 3, needle tip protector  18  is preferably positioned proximate to or toward base portion  25  of needle  21 . This allows a user clear vision and access to the tip of the needle, and minimizes the intrusiveness of needle tip protector  18  in any given medical procedure, whether it is a simple shot, a biopsy or a mammography procedure. Notably, carrier  22  is preferably slightly larger than needle  21 , such that there is little or no frictional contact between carrier  22  and needle  21 , to enable needle  21  to be inserted with ease. Once the needle  21  has been passed through guard  20 , then carrier  22  is promptly removed. There will be frictional contact between needle  21  and the internal workings of guard  20 , to preserve needle guard  20  in place once mounted onto needle  21 . Thus, it is preferred that needle guard  20  is slidably moveable along the needle shaft, but also frictionally held in place once positioned in a desired location on the needle shaft.  
     [0106] Before the needle is used for its desired purpose, carrier  22  is preferably removed from needle tip protector  18  to leave needle guard  20  mounted by itself on needle  21 . This removal is preferably done soon after insertion of needle  21 , although it could be put off. This can be done by simply pulling carrier  22  off of needle  21 , or by using a particular removal tool, such as a pair of pliers, which does not damage the needle. When carrier  22  is slid past shield  28 , aperture  50  in the bottom part of shield  28  surrounds needle  21 , while needle riding lip  54  in upper horizontal leg  48  of shield  28  rests up against needle  21 . Thus, needle guard  20  becomes slidably movable along the needle shaft. The carrier may be easily disposed of.  
     [0107] After the needle has been used for its intended purpose, the needle guard  20  is moved along the needle shaft toward needle tip  23 . Just as needle tip  23  slides past and beyond needle riding lip  54  of shield  28 , spring  26  prompts shield  28  to move in a cantilevering fashion. In particular, spring  26  rocks shield  28  forward, thus forcing upper horizontal leg  48  of shield  28  into locking chamber  40  of shield cavity  32 . As can be seen from FIG. 5, the upper portion of shield covers needle tip  23 , thus preventing the needle from being moved back through the top of needle guard  20 , and into a position where it may harm an individual, or be reused.  
     [0108] At the same time, the sides of aperture  50  of bottom horizontal leg  42  of shield  28  act to grab and freeze needle  21  relative to needle guard  20 . In particular, the cantilevering motion of shield  28  forces the sides of aperture  50  to at least partially dig into needle  21 , thus preventing needle  21  from sliding further away from and out of needle guard  20 , through the bottom side of needle guard  20 . Thus, needle guard  20  is locked directly to needle  21 , with spring  26  exerting the cantilevering force on shield  28  to maintain the needle protector or guard in a position over needle tip  23 . This prevents reuse of needle and prevents inadvertent punctures or injuries which may result from individuals brushing up against the sharp needle tip during disposable or after use.  
     [0109]FIGS. 10 a - 10   e  illustrate housing  24  which is substantially identical to shell  24  of FIGS.  1 - 5  (and accordingly due to the similarity of structure, like reference numerals are employed for the views of FIGS.  1 - 7  and FIGS. 10 a - 10   e ), as well as shell  27 , which can be a simple tube of substantially rectangular cross-section, with rounded corners.  
     [0110]FIG. 11 a  is a side view of a needle guard housing  24 ′ according to an alternative embodiment of the invention, wherein the barbs for affixing the housing to an outer shell (not shown) are omitted. FIG. 11 b  is an end view of the needle guard housing  24 ′ according to the embodiment of FIG. 11 a . FIG. 11 c  is a bottom view of the needle guard housing  24 ′ according to the embodiment of FIG. 11 a . FIG. 11 d  is a top view of the needle guard housing  24 ′ according to the embodiment of FIG. 11 a.    
     [0111]FIG. 12 a  is a schematic illustration of a needle tip guard (minus the carrier or loading tube), according to another alternative embodiment of the invention, shown with the needle in its “in use” position relative to the undeployed needle tip guard. While the carrier or loading tube is omitted from the drawings of this embodiment, it is understood that the guard of this embodiment may be initially provided with a cylindrical tubular carrier, in a manner substantially identical to that disclosed in the embodiment(s) of FIGS.  1 - 3 . Needle tip guard  100  is provided with a housing, generally referred to by reference numeral  102 , in which is positioned a void  104 , which may be generally considered as comprising contiguously arranged chambers  106 ,  108  and  110 , with bearing walls  107 ,  109  and  111 . The outer shell has been omitted from the drawings for clarity of the illustrations. However, it is to be understood that a shell, such as that shown and described with respect to FIGS.  1 - 10   f , may be employed. At the back of void  104  is located back wall  105 . In a preferred embodiment wall  107  deviates 45 degrees from wall  109 , which, in turn, is preferably perpendicular to wall  111 , although some deviations from these respective angular relationships may be employed, if desired. As with the previously described embodiments, while housing  102  may have a generally rectangular parallelepiped configuration, any other suitable configuration may be used. The walls of chambers  106 ,  108  and  110  may be arranged to extend generally perpendicular to the plane of FIG. 12 a . Needle shaft  112  extends longitudinally through housing  102 , in particular through coaxially aligned cylindrical passages  114 ,  116  and  118 .  
     [0112] Shield member  120 , in the embodiment of FIGS. 12 a  and  12   b , comprises a thin flat sheet of metal, e.g., stainless steel, as shown in FIGS. 14 a  and  14   b . The material may be varied, so long as it has sufficient flexibility and resiliency, to withstand being bent, as shown in FIGS. 12 a  and  12   b , without permanently deforming or suffering a significant loss of spring force (for extended shelf life). Shield member  120  is provided with aperture  122 , through which needle shaft  112  is inserted (FIGS. 12 a  and  12   b ). Preferably, aperture  122  is either oval or is circular with a diameter which is somewhat greater than the outside diameter of needle shaft  112 .  
     [0113] When needle shaft  112  is in its “in use” position, with respect to needle guard  100 , shield member  120  is substantially bent, such that the respective ends of shield member  120  have an acute angle between them, of 45 degrees, more or less, and edge  124  of shield member  120  is being pushed (by the resilient spring force stored in member  120 ) against needle shaft  112 . Wall  113  of housing  102  is provided, to act as a locator, giving shield member  120  a surface to butt up against, serving to center aperture  122 , relative to the center of needle shaft  112 .  
     [0114] When the use of the needle has been completed, needle guard  100  is pushed toward and past the needle tip  119  (FIG. 12 b ). As soon as needle tip  119  passes edge  124  of shield member  120 , the stored spring force in shield member  120  causes it to be prompted to “straighten out”. Edge  124  will tend to move up and to the right as shown in FIG. 12 b , while the opposite end of shield member  120  will tend to rotate clockwise, until the edges of aperture  122  come into contact with the surface of needle shaft  112 . Thus, the upper end of shield member  120  prevents needle tip  119  from being pushed out of needle guard  100 , while the lower end of shield member  120 , specifically the upper and lower edges of aperture  122  frictionally engage the sides of needle shaft  112 , thus providing resistance to the removal of needle shaft  112 , through the bottom of needle guard  100 .  
     [0115]FIG. 13 a  is a schematic illustration of a needle tip guard, according to another alternative embodiment of the invention, shown with the needle in its “in use” position relative to the needle tip guard. FIG. 13 b  is a schematic illustration of the needle tip guard according to the embodiment of FIG. 13 a , showing the needle tip in its retracted position, with the guard engaged. While the carrier or loading tube is omitted from the drawings of this embodiment, it is understood that the guard of this embodiment may be initially provided with a cylindrical tubular carrier, in a manner substantially identical to that disclosed in the embodiment(s) of FIGS.  1 - 3 .  
     [0116] To the extent that the structures of FIGS. 13 a ,  13   b ,  15   a ,  15   b  are similar to, and have similar functions, to like elements in the embodiment of FIGS. 12 a ,  12   b ,  14   a ,  14   b , like reference numerals, augmented by a prime (′) will be employed.  
     [0117] Needle tip guard  100 ′ is provided with a housing, generally referred to by reference numeral  102 ′, in which is positioned a void  104 ′, which may be generally considered as comprising contiguously arranged chambers  106 ′,  108 ′ and  110 ′, with bearing walls  107 ′,  109 ′ and  111 ′. At the back of void  104 ′ is back wall  105 ′. The outer shell has been omitted from the drawings for clarity of the illustrations. However, it is to be understood that a shell, such as that shown and described with respect to FIGS.  1 - 10   f , may be employed. In a preferred embodiment wall  107 ′ deviates 45 degrees from wall  109 ′, which, in turn, is preferably perpendicular to wall  111 ′, although some deviations from these respective angular relationships may be employed, if desired. As with the previously described embodiments, while housing  102 ′ may have a generally rectangular parallelepiped configuration, any other suitable configuration may be used. The walls of chambers  106 ′,  108 ′ and  110 ′ may be arranged to extend generally perpendicular to the plane of FIG. 12 a . Needle shaft  112 ′ extends longitudinally through housing  102 ′, in particular through coaxially aligned cylindrical passages  114 ′,  116 ′ and  118 ′. Wall  113 ′ of housing  102 ′ is provided, to act as a locator, serving to center aperture  122 ′, relative to the center of needle shaft  112 ′. While wall  113 ′ does provide some frictional resistance to the end  115 ′ of shield member  120 ′, when guard  100 ′ is deployed (as described in further detail hereinafter), the resistance is not so much that it cannot be overcome upon deployment of guard  100 ′.  
     [0118] Shield member  120 ′, in the embodiment of FIGS. 13 a  and  13   b , comprises a thin, generally flat, sheet of metal, e.g., stainless steel, as shown in FIGS. 15 a  and  15   b , except that instead of presenting a simple straight edge at its upper end, as in the embodiment of FIGS. 12 a ,  12   b , and  14 a and  14   b , the upper end of shield member  120 ′ has been folded back upon itself and curled under to form an elongated U-shaped portion, to present a rounded end  124 ′. The material may be varied, so long as it has sufficient flexibility and resiliency, to withstand being bent, as shown in FIGS. 13 a  and  13   b , without permanently deforming or suffering a significant loss of spring force (for extended shelf life). Shield member  120 ′ is provided with aperture  122 ′, through which needle shaft  112 ′ is inserted (FIGS. 13 a  and  13   b ). Preferably, aperture  122 ′ is either oval or is circular with a diameter which is somewhat greater than the outside diameter of needle shaft  112 ′.  
     [0119] When needle shaft  112 ′ is in its “in use” position, with respect to needle guard  100 ′, shield member  120 ′ is substantially bent, such that the respective ends of shield member  120 ′ have an acute angle between them, of 45 degrees, more or less, and rounded end  124 ′ of shield member  120 ′ is being pushed (by the resilient spring force stored in member  120 ′) against needle shaft  112 ′.  
     [0120] When the use of the needle has been completed, needle guard  100 ′ is pushed toward and past the needle tip  119 ′ (FIG. 13 b ). As soon as needle tip  119 ′ passes rounded end  124 ′ of shield member  120 ′, the stored spring force in shield member  120 ′ causes it to be prompted to “straighten out”. Rounded end  124 ′ will tend to move up and to the right as shown in FIG. 13 b , while the opposite end of shield member  120 ′ will tend to rotate clockwise, until the edges of aperture  122 ′ come into contact with the surface of needle shaft  112 ′. Thus, the upper end of shield member  120 ′ prevents needle tip  119 ′ from being pushed out of needle guard  100 ′, while the lower end of shield member  120 ′, specifically the upper and lower edges of aperture  122 ′ frictionally engage the sides of needle shaft  112 ′, thus providing resistance to the removal of needle shaft  112 ′, through the bottom of needle guard  100 ′.  
     [0121]FIGS. 16 a - 16   e  illustrate a needle tip guard  150 , which has a configuration which is substantially similar to needle tip guard  100  of FIGS. 12 a ,  12   b ,  14   a  and  14   b , except that the manner of engagement between housing  152  and shell  154  is somewhat different. Guard  150  employs a flat shield member  164 . Housing  152  has chambers  156 ,  158  and  160  therein, backed by back wall  161 , which interact with needle shaft  162 , and flat shield member  164 , in a manner substantially identical to that of the embodiment of FIGS. 12 a ,  12   b ,  14   a  and  14   b . Accordingly, the operation of those components is understood to be the same and no further detailed discussion is required. While the carrier or loading tube is omitted from the drawings of this embodiment, it is understood that the guard of this embodiment may be initially provided with a cylindrical tubular carrier, in a manner substantially identical to that disclosed in the embodiment(s) of FIGS.  1 - 3 . Chambers  156  and  158  are provided with walls  163  and  165  respectively, which diverge from one another at a 45 degree angle, as in the embodiment of FIGS. 12 a - b  and  13   a - b.    
     [0122] Instead of barbs  29 , being positioned at an end of the housing, pointing away from the needle tip, as in the embodiment of FIGS.  1 - 10   f , in the embodiment of FIGS. 16 a - 16   e  (in which needle shaft  162  is omitted), barbs  159  are positioned near the end of housing  152 , “pointing” toward the needle tip. Shell  154  is provided with slots  166 , in its side walls, which may be located near each end. During assembly, when shell  154  is initially being pushed onto housing  152 , the tips of barbs  159  must be pushed inwardly, toward the interior of housing  152 . As shell  154  is pushed over housing  152 , once the tips of barbs  159  encounter slots  166 , the stored spring force in barbs  159  causes them to spring outwardly and enter slots  166 , thus securing housing  152  within shell  154 .  
     [0123]FIGS. 17 a - 17   e  illustrate a needle tip guard  176 , which has a configuration which is substantially similar to needle tip guard  150  of FIGS. 16 a - 16   e , except that the shield member is like that of the embodiment of FIGS. 13 a ,  13   b ,  15   a  and  15   b , namely having a U-shaped upper end. Otherwise, the manner of engagement between housing  178  and shell  180  is the same as in the embodiment of FIGS. 16 a    163 . While the carrier or loading tube is omitted from the drawings of this embodiment, it is understood that the guard of this embodiment may be initially provided with a cylindrical tubular carrier, in a manner substantially identical to that disclosed in the embodiment(s) of FIGS.  1 - 3 . Guard  176  employs a shield member  190  having a curved under U-shaped end. Housing  178  has chambers  182 ,  184 ,  186  therein, backed by back wall  187 , which interact with needle shaft  188 , and shield member  190 , in a manner substantially identical to that of the embodiment of FIGS. 13 a ,  13   b ,  15   a  and  15   b . Accordingly, the operation of those components is understood to be the same and no further detailed discussion is required. Chambers  182  and  184  include walls  191  and  193 , respectively, that diverge at a 45 degree angle, preferably, as in the embodiment of FIGS. 12 a - b  and  13   a - b.    
     [0124] As in the embodiment of FIGS. 16 a - 16   e  (in which needle shaft  162  is omitted), barbs  185  are positioned near the end of housing  178 , “pointing” toward the needle tip. Shell  180  is provided with slots  192 , in its side walls, which slots may be located near each end edge of shell  180 . During assembly, when shell  180  is initially being pushed onto housing  178 , the tips of barbs  185  must be pushed inwardly, toward the interior of housing  178 . As shell  180  is pushed over housing  178 , once the tips of barbs  185  encounter slots  192 , the stored spring force in barbs  185  causes them to spring outwardly and enter slots  192 , thus securing housing  178  within shell  180 .  
     [0125]FIG. 18 a  is a side view of a needle tip guard  200  according to another alternative embodiment of the invention, showing the guard with the outer shell omitted, to show an alternative shield member  202 , in its undeployed position. While the carrier or loading tube is omitted from the drawings of this embodiment, it is understood that the guard of this embodiment may be initially provided with a cylindrical tubular carrier, in a manner substantially identical to that disclosed in the embodiment(s) of FIGS.  1 - 3 . Guard  200  operates in a manner substantially similar to that of the guards of the embodiments of FIGS. 16 a - 16   e  and  17   a - 17   e , except that in this embodiment, shield member  202  has a downwardly (i.e., away from the direction of the needle tip) projecting guide lip  204 . In its undeployed position, the guide lip  204  of shield member  202  bears against the side surface of needle shaft  206 .  
     [0126]FIG. 18 b  is a side view of a needle guard according to the alternative embodiment of FIG. 18 a , showing the guard with the outer shell omitted, to show the alternative shield member in its deployed position.  
     [0127]FIGS. 19 a - 19   b  illustrate a needle tip guard  220 , which has a configuration which is substantially similar to needle tip guard  150  of FIGS. 16 a - 16   e . Guard  220  includes housing  222 , with interior void  224 , forming chambers  226 ,  228  and  230 . Guard  220  further includes shield member  232 , which may be substantially identical to shield member  120  of FIGS. 14 a - 14   b . However, unlike the embodiments of FIGS. 12 a - 18   b , in this embodiment, the wall  234  against which shield member  232  slides is not straight; rather, it has a shallow angled portion  236 , which proceeds at an angle of, for example, 35 degrees from the “horizontal” as FIG. 19 b  is viewed (that is, at, preferably, 55 degrees divergence to wall  240 ), whereas portion  238  is steeper, extending at a 45 degree angle to the horizontal and to wall  240 . Also, wall  240  is preferably proportionally longer than the similarly situated walls in the other embodiments. This combination permits shield member  232  to be bent with a larger relative radius of curvature, as compared to the previously described embodiments. This makes installation of the shield member  232  into housing  222  easier, and puts less stress on shield member  232 , in its undeployed position, thus reducing the likelihood of fatigue failure, awaiting use. In addition, the embodiment of FIGS. 19 a ,  19   b  lacks a wall in chamber  230  that is analogous to wall  113  of FIGS. 12 a ,  12   b . Removal of the wall is seen to make the tooling for forming housing  222  simpler and less expensive, and may alleviate possible issues of binding of the end of the shield against that wall, that may occur in the embodiment of FIGS. 12 a - b , for example. Accordingly, as seen in FIG. 19 a , in its undeployed configuration, the lower end of shield member  232  may not be at a substantially perpendicular angle to needle shaft  242 , as in the other previously discussed embodiments. Also, because the centering function is not provided, an edge of the aperture  244  at the lower end may be bearing slightly against the side of needle shaft  242 . However, this frictional force will not be sufficient to prevent movement of shaft  242  relative to housing  222 , towards deployment of guard  220 . However, once deployment has occurred, the lower end of shield member  232  adopts an oblique angle with respect to needle shaft  242 , with substantially increased frictional force acting to resist further movement of needle shaft  242 , relative to housing  222 . While the carrier or loading tube is omitted from the drawings of this embodiment, it is understood that the guard of this embodiment may be initially provided with a cylindrical tubular carrier, in a manner substantially identical to that disclosed in the embodiment(s) of FIGS.  1 - 3 .  
     [0128]FIGS. 19 c - 19   d  illustrate a needle tip guard  250 , which has a configuration which is substantially similar to needle tip guard  176  of FIGS. 17 a - 17   e . Guard  250  includes housing  252 , with interior void  254 , forming chambers  256 ,  258  and  260 . Guard  250  further includes shield member  262 , which may be substantially identical to shield member  120 ′ of FIGS. 15 a - 15   b . However, unlike the embodiments of FIGS. 12 a - 18   b , in this embodiment, the wall  284  against which shield member  252  slides is not straight; rather, it has a shallow angled portion  286 , which proceeds at an angle of, e.g., 35 degrees from the “horizontal” as FIG. 19 c  is viewed (that is, at, preferably, 55 degrees divergence to wall  240 ), whereas portion  288  is steeper, extending at a 45 degree angle to the horizontal and to wall  270 . Also, wall  270  is preferably proportionally longer than the similarly situated walls in the other embodiments. This combination permits shield member  262  to be bent with a larger relative radius of curvature, as compared to the previously described embodiments. This makes installation of the shield member  262  into housing  252  easier, and puts less stress on shield member  252 , in its undeployed position, thus reducing the likelihood of fatigue failure, awaiting use. In addition, the embodiment of FIGS. 19 c ,  19   d  lacks a wall in chamber  260  that is analogous to wall  113  of FIGS. 12 a ,  12   b . Removal of the wall is seen to make the tooling for forming housing  252  simpler and less expensive. Accordingly, as seen in FIG. 19 c , in its undeployed configuration, the lower end of shield member  262  may not be at a substantially perpendicular angle to needle shaft  272 , as in the other previously discussed embodiments. Also, because the centering function is not provided, an edge of the aperture  274  at the lower end may be bearing slightly against the side of needle shaft  272 . However, this frictional force will not be sufficient to prevent movement of shaft  272  relative to housing  252 , towards deployment of guard  250 . However, once deployment has occurred, the lower end of shield member  262  adopts an oblique angle with respect to needle shaft  272 , with substantially increased frictional force acting to resist further movement of needle shaft  272 , relative to housing  252 . While the carrier or loading tube is omitted from the drawings of this embodiment, it is understood that the guard of this embodiment may be initially provided with a cylindrical tubular carrier, in a manner substantially identical to that disclosed in the embodiment(s) of FIGS.  1 - 3 .  
     [0129] A still further alternative embodiment of the invention is shown in FIGS. 20 a ,  20   b  and  20   c . While the carrier or loading tube is omitted from the drawings of this embodiment, it is understood that the guard of this embodiment may be initially provided with a cylindrical tubular carrier, in a manner substantially identical to that disclosed in the embodiment(s) of FIGS.  1 - 3 . In this embodiment, needle tip guard  300  includes a housing  302  with suitable bores for passage therethrough of a needle shaft, an inner support block  304 , biasing member (i.e., spring)  306 , pivoting member  308  and clamp plate  309 . Inner support block  304  emanates from back wall  305  of housing  302 . Housing  302  is surrounded by an outer shell which may have any desired configuration (such as a hollow rectangular tube, as shown and described with respect to previously shown embodiments), and thus which has been omitted for clarity of the illustration of the inner components. Housing  302  is configured to slidably move along needle shaft  312 , and may have any desired configuration, so long as it provides an interior corner  314  to act as a fulcrum for pivoting member  308 , as described hereinafter. Block  304  is provided with a through bore, to permit the free sliding movement of needle shaft  312  therethrough. Block  304  also has a blind bore  316 , for receiving biasing member  306 , and a diagonal corner portion  318 , which is provided to give room for the pivoting member  308 . Pivoting member  308  has a web  320 , which connects arms  322 ,  324 . Arm  322  has an aperture  326 , which is configured to let needle shaft  312  pass freely therethrough. Arm  324  is provided with aperture  328  which may be in the form of an elongated ellipse, or of sufficiently large diameter, so as not to bind on needle shaft  312 , when pivoting member  308  is in the deployed configuration of FIG. 20 b . Beneath pivoting member  308 , between arm  324  and the interior corner  314  is positioned clamp plate  309 , which has an aperture  330 , which is slightly larger than the diameter of needle shaft  312 , and which further has sharp corners therein, to grip into needle shaft  312 , when pivoting member  308  is in its deployed position.  
     [0130] When needle guard  300  is in the position of FIG. 20 a , biasing member  306  is in compression. When guard  300  is slid down needle shaft  312 , as soon as the needle tip clears aperture  326 , the lateral force exerted by needle shaft  312  against the interior surface of aperture  326  (in reaction to the force being exerted by biasing member  306  to pivot pivoting member  308 ) is removed, and pivoting member  308  is free to pivot, around corner  314 , to the extent that diagonal portion  318  permits. During this pivoting the inside corner edges of aperture  330  of clamp plate  309  will engage needle shaft  312 , providing frictional resistance to the further sliding of needle shaft  312 , relative to guard  300 . Arm  322  will have sufficient length to prevent the reemergence of the needle tip out of the front of guard  300 .  
     [0131] A still further alternative embodiment of the invention is shown in FIGS. 21 a ,  21   b  and  21   c . While the carrier or loading tube is omitted from the drawings of this embodiment, it is understood that the guard of this embodiment may be initially provided with a cylindrical tubular carrier, in a manner substantially identical to that disclosed in the embodiment(s) of FIGS.  1 - 3 . In this embodiment, needle tip guard  400  includes a housing  402  with suitable bores for passage therethrough of a needle shaft, an inner support block  404 , biasing member (i.e., spring)  406 , and pivoting member  408 . Housing  402  is provided with a back wall  405 , from which block  404  projects. Housing  402  is surrounded by an outer shell which may have any desired configuration, and thus which has been omitted for clarity of the illustration of the inner components. Housing  402  is configured to slidably move along needle shaft  412 , and may have any desired configuration, so long as it provides an interior corner  414  to act as a fulcrum for pivoting member  408 , which is rotated  90  degrees with respect to block  404 , relative to the spatial relationship between block  304  and pivoting member  308 , of the embodiment of FIGS. 20 a  and  20   b . Block  404  is provided with a through bore, to permit the free sliding movement of needle shaft  412  therethrough. Block  404  also has a blind bore  416 , for receiving biasing member  406 , and a diagonal corner portion  418 , which is provided to give room for the pivoting member  408 . Pivoting member  408  has a web  420 , which connects arms  422 ,  424 . Arm  422  has an aperture  426 , which is configured to let needle shaft  412  pass freely therethrough. Arm  424  is provided with aperture  428  which may be in the form of an elongated ellipse, or of sufficiently large diameter, so as to bind on needle shaft  412 , when pivoting member  408  is in the deployed configuration of FIG. 21 a.    
     [0132] When needle guard  400  is in its undeployed position, biasing member  406  is in compression. When guard  400  is slid down needle shaft  412 , as soon as the needle tip clears aperture  426 , the lateral force exerted by needle shaft  412  against the interior surface of aperture  426  (in reaction to the force being exerted by biasing member  406  to pivot pivoting member  408 ) is removed, and pivoting member  408  is free to pivot, around corner  414 , to the extent that diagonal portion  418  permits. During this pivoting the inside corner edges of aperture  428  of pivoting member  408  will engage needle shaft  412 , providing frictional resistance to the further sliding of needle shaft  412 , relative to guard  400 . Arm  422  will have sufficient width to prevent the reemergence of the needle tip out of the front of guard  400 .  
     [0133] A still further alternative embodiment of the invention is shown in FIGS. 22 a ,  22   b  and  22   c . While the carrier or loading tube is omitted from the drawings of this embodiment, it is understood that the guard of this embodiment may be initially provided with a cylindrical tubular carrier, in a manner substantially identical to that disclosed in the embodiment(s) of FIGS.  1 - 3 . In this embodiment, needle tip guard  500  includes a housing  502  with suitable bores for passage therethrough of a needle shaft, an inner support block  504 , biasing member (i.e., spring)  506 , and pivoting member  508 . Housing  502  is provided with a back wall  505 , from which block  504  projects. Housing  502  is also surrounded by an outer shell (not shown) which may have any desired configuration, and thus which has been omitted for clarity of the illustration of the inner components. Housing  502  is configured to slidably move along needle shaft  512 , and may have any desired configuration, so long as it provides an interior corner  514  to act as a fulcrum for pivoting member  508 , which is rotated 90 degrees with respect to block  504 , relative to the spatial relationship between block  304  and pivoting member  308 , of the embodiment of FIGS. 20 a  and  20   b . Block  504  is provided with a through bore, to permit the free sliding movement of needle shaft  512  therethrough. Housing  502  has a blind bore  516 , for receiving biasing member  506 . Block  504  has a removed corner portion  418 , which is provided to give room for the pivoting member  508  to tilt, as shown in FIG. 22 a . Pivoting member  508  has a web  520 , which connects arms  522 ,  524 . Arm  522  has an aperture  526 , which is configured to let needle shaft  512  pass freely therethrough. Arm  524  is provided with aperture  528  which may be in the form of an elongated ellipse, or of sufficiently large diameter, so as to bind on needle shaft  512 , when pivoting member  508  is in the deployed configuration of FIG. 22 a.    
     [0134] When needle guard  500  is in its undeployed position, biasing member  506  is in compression. When guard  500  is slid down needle shaft  512 , as soon as the needle tip clears aperture  526 , the lateral force exerted by needle shaft  512  against the interior surface of aperture  526  (in reaction to the force being exerted by biasing member  506  to pivot pivoting member  508 ) is removed, and pivoting member  508  is free to pivot, around corner  514 , to the extent that removed corner portion  518  permits. During this pivoting the inside corner edges of aperture  528  of pivoting member  508  will engage needle shaft  512 , providing frictional resistance to the further sliding of needle shaft  512 , relative to guard  500 . Arm  522  will have sufficient width to prevent the reemergence of the needle tip out of the front of guard  500 .  
     [0135] Another alternative embodiment of the invention is shown in FIGS. 23 a ,  23   b  and  23   c . While the carrier or loading tube is omitted from the drawings of this embodiment, it is understood that the guard of this embodiment may be initially provided with a cylindrical tubular carrier, in a manner substantially identical to that disclosed in the embodiment(s) of FIGS.  1 - 3 . Guard  600  includes housing  602 , having suitable bores therethrough for passage of a needle shaft  630 . Guard  600  may have an outer shell of any suitable configuration. Accordingly the shell has been omitted from the drawings for simplicity of illustration of the invention. Housing  602  is provided with a back wall  605 , from which block  607  projects.  
     [0136] Guard  600  also includes a clamp plate  604 , having clamping aperture  606 ; biasing member (e.g., spring)  608 , which resides in blind bore  610 ; sliding member  612  which includes web  614 , leg  616  and leg  618 ; and pivoting member  620 , which includes legs  622  and  624  (disposed at 90 degrees to one another). Aperture  606  of clamp plate  604  is either an ellipse or circular with a diameter sufficiently large to permit ready passage of needle shaft  630 , but will bind thereon, once clamp plate  604  has pivoted, as in FIG. 23 b.    
     [0137] Leg  616  of sliding member  612  is positioned between clamp plate  604  and an inner bottom surface of void  640  of housing  602 . Sliding member  612  is constrained to move vertically (relative to housing  602  in FIGS. 23 a  and  23   b ) by walls  642  and  644 . In the undeployed configuration, the underface of leg  618  of sliding member  612  bears down against an upper face of leg  622  of pivoting member  620 . The lower face of leg  622  of pivoting member  620  rests atop the end of ledge  626 . Biasing member  608  is in compression in FIG. 23 a.    
     [0138] In moving guard  600  to its deployed position, once tip  632  of needle shaft  312  has passed by the outer face of leg  624  of pivoting member  620 , the force stored in and exerted by biasing member  608  pushes clamp plate  604  downwardly, causing clamp plate  604  to pivot about interior corner  650  of housing  602 .  
     [0139] The downwardly moving end of clamp plate  604  in turn pushes down against leg  616  of sliding member  612 . This, in turn, causes leg  618  to push down against leg  622  of pivoting member  620 , causing pivoting member  620  to pivot about ledge  626 , causing leg  624  to swing up, and block the path through which tip  632  has just passed, preventing re-emergence of tip  632  out of the front of housing  602 . The end face of leg  618  bears against the face of leg  622  to prevent further pivoting about ledge  626 . At the same time, the inner edges of aperture  606  of clamp plate  604 , as described hereinabove, bind needle shaft  630  to retard removal of guard  600  off of shaft  630 .  
     [0140] In each of the several embodiments discussed herein, the housing components, such as the outer shells and housing, may preferably be fabricated from plastics or similar materials, while the moving, sliding, bending or clamping parts herein are preferably fabricated from metallic materials, for strength, resilience, and the ability to frictionally engage, if not actually “bite into” the needle shafts of the needles with which these structures will be used.  
     [0141] Furthermore, in each embodiment of the invention discussed herein, the needle tip guards may be used by themselves, or more preferably they may be used in combination with a needle carrier  22  such as that shown in and described with respect to the embodiment of FIGS.  1 - 3 , for facilitating insertion of a needle shaft into a needle tip guard, without damaging the tip of the needle.  
     [0142] While in each of the embodiments shown hereinabove, the housings are in the form of asymmetrical molded, stamped or machined bodies, having openings on one side only, and then insertingly received in outer shells, in alternative embodiments of the invention, the housings could be in the form of mirror-image (or nearly mirror-image) housing halves, into which the working components are mounted, and then the halves mated and affixed to one another, such as by adhesive, or sonic welding, or any other suitable method.  
     [0143] The foregoing description and drawings merely explain and illustrate the invention, and the invention is not limited thereto, except as those skilled in the art who have the present disclosure before them will be able to make modifications and variations therein without departing from the scope of the invention.