Abstract:
Improvements in a safety hypodermic needle and a method of making the same are disclosed. The improvements relate to a commercial embodiment of a patented safety needle and comprise a tubular member extruded from a flexible elastomeric or rubber-like polymeric material. The tubular member is extruded with two ribs extending from the outer wall of the tubular member and spaced apart 90° circumferentially. The wall of the tubular member is provided with through cuts to form a cutout on one wall portion and an elongated lever on the opposite wall portion in the 90° space between the ribs. The cuts separate the wall of the tubular member into two outwardly flexible arms, each having a single rib thereon adjacent an edge of the arm. One end of the tubular member is stretched over the needle hub of a hypodermic needle and the other end is stretched over a needle cup which houses the sharp needle point. The needle cup is provided with a needle opening through which the needle extends during use. After use the flexible arms automatically return the needle cup into a protective position housing the needle point. Latching mechanisms are provided on the hub and lever for releasably holding the arms in a “cocked” position or for permanently holding the arms in a disabled or “safe” condition to prevent inadvertent needle sticks.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to hypodermic syringes and phlebotomy apparatus and more particularly to improvements in a protective cover for the hypodermic needle of disposable hypodermic syringes and phlebotomy apparatus that advantageously prevent inadvertent needle sticks or punctures, both before and after use of the syringe or apparatus. 
     2. Description of the Prior Art 
     Infectious diseases can be transmitted to medical personnel and others by way of inadvertent needle sticks or punctures with an infected needle of a hypodermic syringe or phlebotomy apparatus. Cases have been reported in which human HIV (AIDS) infection and other infectious diseases have been transmitted by accidental or inadvertent needle sticks. A number of devices have been developed for the purpose of preventing such needle sticks. 
     One type of prior art device in common use employs a protective sheath external to the needle which is retractable to permit insertion of the needle into the body of the patient and is then slidable back over the needle past the needle point as, or after, the needle is withdrawn from the body. In some of this type of prior art protective device, a spring or axially resilient sheath is used to extend the sheath over the needle point upon withdrawal of the needle. Several of these prior art devices use a collapsible sheath formed by a plurality of resilient arms surrounding the needle and a needle cup that encloses the needle tip and prevents inadvertent needle sticks. An offset needle opening is provided in the end of the needle cup. The arms are bowable or bendable outwardly away from the needle axis and permit the needle to be guided through the offset opening for use. After use, the arms are movable inwardly toward the needle axis with or without a biasing means to again enclose the needle point within the needle cup. One example of such prior art devices is described in my U.S. Pat. No. 5,256,152. 
     Another example of such prior art devices is disclosed in U.S. Pat. Nos. 5,538,508 and 5,746,718 issued to Steyn, the entire subject matter of which is incorporated herein by reference. In a commercial embodiment of the Steyn safety needle device, very similar to the embodiment shown in FIGS. 1 and 2 of the Steyn patents, the needle cup is a molded polymeric end cap with an offset needle opening. The collapsible sheath is formed from a length of an extruded flexible polymeric tube with four reinforcing ribs projecting radially from the circumference of the extruded tube and equi-angularly spaced at 90° about the tube circumference. As used herein, the term “rib” or “ribs” is used to describe the longitudinally extending projection(s) from the outer circumference of the tubular member. Except for circumferential portions at the proximal and distal ends of the sheath, two opposing walls of the extruded tube between the ribs are cut out to form two flexible opposing arms, each arm having an extruded rib extending along each of its two edges. One end of the extruded tube is stretched over the needle cup and the other end is stretched over the needle support base. Notches are provided on the inside of the arms midway between the ends of the sheath which are intended to cause the arms to bow outwardly when the tubular member is axially compressed. As the two aims bow outwardly to their maximum extent, they also fold rearwardly toward the syringe barrel so that the user can manually grasp and hold the arms against the syringe barrel when administering an injection. 
     Although this commercial embodiment of the Steyn safety needle device is operable for its intended purpose, it has several shortcomings that can be eliminated by the improvements disclosed herein according to the present invention. In particular, those shortcomings include: (1) the flexible arms do not reliably flex outwardly when the needle is deployed, but frequently flex inwardly; (2) because of excessive lateral movement of the needle inside the needle cup, the needle point may miss the needle opening and strike the inside face of the end of the needle cup requiring repeated attempts to align the needle with the opening; (3) the user must grasp the needle cup with the fingers of one hand and urge it proximally toward the needle support thereby placing the user&#39;s fingers in very close proximity to the needle point and shaft, which could easily cause an inadvertent needle stick and/or contamination of the needle point and shaft; (4) the arms flex outwardly and rearwardly alongside the barrel of the syringe so that the user has only one hand free (one hand is holding the needle cup) to both hold the syringe and grip at least one arm and press it against the surface of the syringe barrel to keep the needle exposed for use, an extremely awkward maneuver; and (5) the device has no means for disabling itself after use to prevent its accidental reuse. 
     Furthermore, one of the primary shortcomings of many the prior art devices which use protective sheaths of the foregoing type is that during at least some of the period of time between the preparation of the hypodermic syringe for an injection, or the phlebotomy apparatus for entering a vein, and the discarding of the used needle, inadvertent needle sticks of persons other than the patient are still possible. 
     It would be desirable, therefore, to provide a safety hypodermic needle for use with a disposable hypodermic syringe, as well as for use with catheter needles and other types of body-penetrating hypodermic needles, that overcomes the foregoing limitations and shortcomings of the commercial embodiment of the Steyn safety needle device as well as other prior art devices, has a minimum number of parts, is economical to manufacture and is easy and convenient to use. The present invention overcomes the aforementioned limitations of the commercial embodiment of the Steyn safety needle device and provides still further improvements over those other prior art safety devices for hypodermic needles as will be described in detail in the following specification. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to improvements in protective covers for hypodermic needles and, in particular, to improvements in the commercial embodiment of the Steyn safety needle device and in the method of making it to more effectively prevent inadvertent needle sticks and to be more versatile. The safety needle of the invention comprises a needle, typically a hollow, hypodermic needle shaft with a sharp bevel point or tip, a needle support hub into which the needle shaft is inserted and a protective sheath which is affixed at one end to the hub and at least partially encloses the greater part of the longitudinal extent of the needle shaft and completely encloses the needle point in a needle cup until the needle is ready to be inserted in the body. The needle cup has a closed end with a needle opening radially offset from the cup center and through which the needle passes during use. 
     The protective sheath is preferably cut from a length of an extruded polymeric material, such as silicone rubber, polyethylene, polypropylene or the like, and preferably a clear or transparent rubber-like or elastomeric material. Other manufacturing techniques, such as injection molding, may be employed. The protective sleeve or sheath may also be made of different materials, preferably polymeric materials, and assembled together in its final form. In addition, the protective sheath may be molded or made with regions of different stiffness so that some regions are more or less flexible than others. 
     The protective sheath is preferably extruded in a generally tubular form with a circular or elliptical cross-section and two radial ribs circumferentially spaced about 90° apart around the outer surface of the extruded tube (as distinguished from the four radial ribs disclosed in the Steyn patents and provided in the commercial embodiment thereof). The extruded tube is then cut to appropriate lengths for assembly with a needle cup at one end of the tube and with a support huh of a needle at the other end of the tube. It has also been found that the two ribs need not extend in a precise radial orientation from the outer circumference of the tubular member, but rather may have other than radial orientations. The number of ribs may also vary so long as they are positioned on the outer circumference of the tubular member as described below. 
     In the commercial embodiment of the Steyn safety needle device, generally rectangular portions of two opposing walls of the tubular sheath intermediate the ends are completely cut away to provide a pair of outwardly bowable flexible arms, each arm having two extruded radial ribs, one rib extending along each of the two edges of each arm. According to the method and apparatus aspects of the present invention, the 90° wall portion between the ribs, a first wall portion, is cut through along only three sides leaving one narrow side of the first wall portion still attached to the tube at one end for use as a cocking lever to be described further herein. An opposing second wall portion of substantially the same size and circumferential extent as the first wall portion is completely cut away on four sides leaving two flexible arms as in the Steyn device, but with at least one rib extending along the upper edge of each arm. The extruded tube of the invention with at least two outwardly extending ribs, and at least one rib along the upper edge of each arm is cut to appropriate lengths and one end is stretched over the support hub of a hypodermic needle and the other end, to which the cocking lever is attached, is stretched over the proximal end of the needle cup with the center of the offset needle opening of the cup disposed 180° around the tube circumference from the longitudinal axis of the first wall portion and about 135° around the tube circumference from each of at least the two outwardly extending ribs. 
     According to the present invention, the provision of at least one rib along the upper edge of each flexible arm adjacent the first wall portion or cocking lever and no ribs along the lower edge of each flexible arm causes the arms of the protective sheath to reliably flex outwardly away from the needle axis rather than flex inwardly as frequently occurs with the four-rib construction, i.e., a rib along both upper and lower edges of each flexible arm, of the commercial embodiment of the Steyn device when the needle cup is retracted rearwardly to expose the needle. 
     As previously mentioned, according to the invention, the first wall portion is used as a cocking lever which is grasped by the user and articulated upwardly, then rearwardly toward the syringe barrel to, first align the needle with the offset needle cup opening, then cause the flexible arms to how outwardly and guide the needle point through the needle cup opening. The provision of the cocking lever advantageously permits the user to expose the needle for use without having to grasp the needle cup as is necessary when using the patented and commercial embodiments of the Steyn device with the attendant possibility of an inadvertent needle stick. The cocking lever may be provided with a tab attached at the free end of the lever which may be used for holding the cocking lever against the syringe barrel with the protective sheath and needle in the “ready for use” condition. When the needle is inserted in the patient&#39;s body, the tab may be released and the medication is injected through the needle. Upon completion of the injection, the needle is withdrawn from the patient&#39;s body and the aims automatically return to their unbowed or unflexed condition with the needle cup again enclosing the needle point in the “safe” condition. 
     Preferably, however, the cocking lever and the needle hub support are provided with first interengaging components to form a manually-operated latching mechanism for securing the protective sheath in its “ready for use” or “cocked” position so that it is unnecessary for the user to hold the cocking lever against the syringe barrel in preparation for giving an injection. Upon giving the injection, the latching mechanism is automatically released when the needle cup engages the patient&#39;s body and the flexed arms automatically return to their unbowed or unflexed “safe” condition with the needle cup again enclosing the needle point. The tubular member and/or the cocking lever and/or the needle hub support are preferably provided with second interengaging components for disabling the syringe by securing the protective sheath in the “at rest,” unflexed or “safe” condition alter it has been used to prevent inadvertent reuse. With the second interengaging components engaged, the protective sheath cannot be operated to expose the needle point. This disabled condition signifies to medical personnel that the syringe has been used and should be discarded. Also, in this way, a needle which is potentially contaminated with the body fluids of a patient carrying an infectious disease is rendered safe from the standpoint of inadvertent needle sticks. 
     The needle cup according to the invention is an injection molded component that differs from the needle cup of the commercial embodiment of the Steyn device in that it is provided with a relatively small, generally V-shaped guiding channel to insure that, before the protective sheath is retracted or “cocked” with the cocking lever, the needle shaft is positively guided into alignment with the offset opening in the distal end of the needle cup, unlike the operation of the commercial embodiment of the Steyn device. 
     The safety needle of the invention can also be used in medical procedures for inserting catheters into blood vessels with a needle, in phlebotomy procedures and in other procedures in which hypodermic needles are used and the danger of inadvertent needle sticks exist. 
     Although a number of improvements to the Steyn safety needle device are disclosed in the specification and accompanying drawings, it should be understood that, apart from the specific embodiments disclosed herein, this invention is generally applicable to any type of hypodermic needle used to penetrate the body to either introduce a substance into the body or to withdraw a substance from the body, such as blood or other body fluids. 
     With the foregoing and other objects, advantages and features of the invention that will become hereinafter apparent, the nature of the invention may be more clearly understood by reference to the following detailed description of the invention, the appended claims and to the several views illustrated in the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top plan view of the prior art commercial embodiment of the Steyn safety needle device in its “at rest” or unflexed condition; 
         FIG. 1A  is a cross-sectional view of the prior all commercial embodiment of the Steyn safety needle device taken along line  1 A- 1 A of  FIG. 1 ; 
         FIG. 2  is a partial longitudinal cross-section of the prior art commercial embodiment of the Steyn safety needle device of  FIG. 1 ; 
         FIG. 3  is a perspective view illustrating a longitudinal section of the extruded elastomeric tube used to construct the prior art commercial embodiment of the Steyn safety needle of  FIG. 1 ; 
         FIG. 4  is a perspective view illustrating a longitudinal section of the extruded tube used to construct the protective sheath of the improved safety needle device of the present invention; 
         FIG. 5  is a top plan view of one embodiment of the improved safety needle device of the present invention in the initial or “safe” condition; 
         FIG. 5A  is a cross-sectional view of the embodiment of the improved safety needle device of the present invention taken along line  5 A- 5 A of  FIG. 5 ; 
         FIG. 6  is a bottom plan view of the  FIG. 5  embodiment of the improved safety needle device of the present invention; 
         FIG. 7  is a partial longitudinal cross-section of the  FIG. 5  embodiment of the improved safety needle device of the present invention; and 
         FIG. 8  is a cross-sectional view of the needle cup of the improved safety needle device of the present invention taken along line  8 - 8  of  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now in detail to the drawings, there is illustrated in  FIGS. 1-3  and  1 A a prior art commercial embodiment of the Steyn needle protective device  10  substantially as shown in FIGS. 1 and 2 of U.S. Pat. Nos. 5,538,508 and 5,746,718. Device  10  comprises a needle assembly  12 , an extruded elastomeric tubular member  14  with four equi-angularly spaced, radial ribs  16  (see also  FIG. 3 ) and a needle cup  18 . The needle assembly  12  is conventional and includes a huh  20 , an end flange  22  and an elongate hypodermic needle  24  having a beveled point  26  and extending axially from the hub  20 . Needle cup  18  is an injection molded member having a tubular wall  28  and a blocking end wall  30  with an elongated opening  32  ( FIGS. 1A and 2 ) through which the needle  24  is adapted to pass. As best shown in the transverse section of  FIG. 1A , the axes of the needle  24  and the needle cup  18  are offset so that the needle  24  is misaligned with the opening  32  in the cup cavity  33  to thereby prevent the needle  24  from passing through the opening  32  until the user manually aligns them with the fingers of one hand. 
     The top and bottom opposing walls of extruded tubular member  14  are provided with longitudinal cut-outs  34  (only the top cutout shown in  FIG. 1 ) that form a pair of flexible arms  36  each with a pair of ribs  16  ( FIG. 1A ) extending adjacent the upper and lower edges thereof (only upper edges  35  are shown in  FIG. 1 ). One end  37  of the tubular member  14  is stretched over the needle hub  20  and the other end  38  is stretched over the needle cup  18  to assemble the protective needle device  10 . Other details of the construction and operation of the protective needle device  10  are described in the aforementioned Steyn patents. 
     As described above, the commercial embodiment of the Steyn safety needle device  10  has several shortcomings, including: (1) the flexible arms  36  do not reliably flex outwardly when the needle  24  is deployed through opening  32 , but frequently flex inwardly; (2) because of excessive lateral movement of the needle  24  inside the needle cup  18  ( FIG. 1A ), the point  26  of needle  24  frequently misses the needle opening  32  and strikes the inside face of the blocking end  30  of the needle cup  18  requiring repeated attempts by the user to align the needle with the opening; (3) the user must grasp the needle cup  18  with the lingers of one hand and urge it proximally toward the needle huh  20  thereby placing the user&#39;s fingers in dangerously close proximity to the needle point  26  and needle  24 , which could cause an inadvertent needle stick and/or contamination of the needle point and needle; (4) as the arms  36  flex outwardly and rearwardly alongside the barrel of the syringe (not shown), the user has only one hand free (the other hand is holding the needle cup  18 ) to both hold the syringe and grip at least one flexible arm  36  and press it against the surface of the syringe barrel to keep the needle exposed for use, an extremely awkward maneuver; and (5) the device  10  has no means for disabling it after use to prevent its accidental reuse. 
     Referring now to  FIGS. 4-5 ,  5 A and  6 - 8 , one embodiment of the improved safety needle device  40  according to the present invention is illustrated. First, referring to  FIG. 4 , there is shown a section of an extrusion  42  that can be used for the protective sheath or tubular member  44  of the safety needle device  40  of the invention. Extrusion  42  has two radial ribs  46  spaced about 90° apart on the circumference thereof instead of the four ribs  16  of the prior art tubular member  14  shown in  FIG. 3  and is preferably extruded from a clear, flexible elastomeric or rubber-like polymeric material, such as silicone rubber. Instead of the two radial ribs  46 , other orientations and configurations of the two ribs  46  may be employed. 
       FIG. 5  is a top plan view of the improved safety needle device  40  (the top of the device  40  as described herein is the circumferential portion of the tubular member  44  that includes the two ribs  46 ). The top wall of the tubular member  44  between the ribs  46  is cut through along three sides  48   a ,  48   b  and  48   c  as shown in  FIG. 5  to form an elongated lever or tab  48  that remains connected to the tubular member  44  only at its distal end  50 . Lever  48  is provided with a through hole  52  and a pin  55  along its longitudinal axis for purposes to be described hereinafter. 
       FIG. 6  is a bottom plan view of the improved safety needle device  40  (the bottom of the device  40  is the circumferential portion of the tubular member  44  directly opposite the midpoint between the two ribs  46 ). The bottom wall of the tubular member  44  is cut away from the distal end  50  of the tubular member to its proximal end  54  to form an essentially rectangular cutout  56  with curved ends  58 ,  60 . The circumferential width of the cutout  56  is substantially the same as the circumferential width of the lever  48 . 
     Needle assembly  62  is conventional and includes a hub  64 , an end flange  66  and an elongate hypodermic needle  68  having a beveled point  70  extending axially from the hub  64 . According to the invention, a latching mechanism  72  ( FIG. 7 ) comprises a sleeve  73  that is slid over mid fastened, e.g., adhesively, to hub  64  of the needle assembly  62 . Alternatively, sleeve  73  may be sized so as to be secured to huh  64  with an interference fit. Sleeve  73  has a projection or abutment  75  on the top side thereof that has a circumferential width slightly less than the circumferential width of lever  48  (see  FIG. 5 ). A rearwardly inclined latch pin  76  and a small bore  77  are formed along the longitudinal axis of the abutment  75  for engagement with the hole  52  and disabling pin  55 , respectively, as described in more detail hereinafter. 
     Needle cup  80  is preferably an injection molded member having a cylindrical wall  82  with an external annular flange  83  and a blocking end wall  84  with an opening  86  ( FIGS. 5 ,  5 A,  7  and  8 ) through which the needle  68  is adapted to pass. To assemble the tubular member  44  with the needle assembly  62  and needle cup  80 , the distal and proximal ends  50 ,  54  of the tubular member  44  are stretched over the needle cup  80  and needle hub  64 , respectively, up to the respective flanges  83 ,  66 . 
     As shown in the partial longitudinal section of  FIG. 7  and the cross-sections of  FIGS. 5A and 8 , the axes of the needle  68  and the needle cup  80  are offset so that the needle point  70  is misaligned with the opening  86  in the cup to thereby prevent the needle  68  from passing through the opening  86  until they are aligned with one another. This misalignment may be effected in at least two ways as explained in the Steyn patents, namely, by cutting off one end of the tubular member at an angle to the longitudinal axis thereof or by leaving a gap between a portion of the end lace of the tubular member  44  and a respective flange  66  or  83 . Other ways of effecting the misalignment will be apparent to those skilled in the art. 
     The bottom cutout  56  and cut sides  48   a ,  48   h  and  48   c  on the top of the tubular member  44  form two outwardly flexible arms  44   a ,  44   b  of the remaining two opposing circumferential portions of the tubular member  44 . Each flexible arm has one rib  46  extending from the arm adjacent a respective cut side  48   a  and  48   b  on the top of the tubular member  44  ( FIG. 5 ). Because each arm  44   a ,  44   h  has a rib  46  adjacent the top edge thereof (and no rib on the lower edge thereon, the arms consistently and reliably flex outwardly away from the needle  68  when the needle  68  is aligned with the opening  86  and the cup  80  is moved proximally toward the needle huh  64 . Notches  44   c ,  44   d ,  44   e  and  44   f  may be provided at the midpoint of the upper and lower edges of the arms to aid in causing the arms  44   a ,  44   b  to flex at their midpoints rather than at another longitudinal position along the arms. Notches  45  ( FIG. 5 ) may also be provided on the outermost edges of the ribs  46  for a purpose to be hereinafter described. 
       FIG. 5A  is a cross-section of the device  40  and  FIG. 8  is a cross section of the needle cup  80  showing the misaligned relationship between the needle  68  and the opening  86  in the initial or “at rest” condition of the safety needle device  40  with the needle  68  confronting the blocking end wall  84 . The interior cavity  85  of the needle cup  80  is relatively small in volume compared to the volume of cavity  33  of the cup  18  of the commercial embodiment of the Steyn device. Cavity  85  is also substantially V-shaped in cross-section so as to assist in guiding the needle  68  into the opening  86  when the safety needle device is operated as described below. The shape and small volume of the internal cavity  85  of the needle cup  80  helps prevent the needle point  70  from striking the blocking end face  84  of the needle cup  80  when the needle is guided toward the opening  86 . This shape is an improvement over the internal shape of the safety needle device shown in FIG. 6 of the Steyn patents and in the commercial embodiment of the Steyn device. 
     To operate the improved safety needle device  40  of the invention, the device  40  would typically be attached to a medication-containing syringe (not shown) at the needle hub  64 . Holding the syringe in one hand, the user grasps the lever  48  with the lingers of the other hand and moves it upwardly away from the axis of the device as shown by the arrow M in  FIG. 7 . The position of the abutment  75  beneath the lever  48  raises the lever above the tubular member  44  (see  FIG. 7 ) and facilitates the user grasping the lever. 
     Importantly, and unlike the Steyn safety needle device, during operation of the device  40  of the invention, the users fingers are safely positioned adjacent the syringe and needle hub  64  and well away from the needle cup  80  so that there is no danger of an inadvertent stick with the needle point  70 . Continued movement of the lever  48  first upwardly and then slightly rearwardly causes the arms  44   a ,  44   h  to begin to flex outwardly and the needle cup  80  to move relative to the needle  68  and needle point  70  in a direction to align the needle  68  with the opening  86 . The internal substantially V-shaped or cavity  85  of the needle cup  80  guides the needle  68  until the needle point  70  is aligned with the opening  86 . The user then pulls the lever  48  farther rearwardly (axially) toward the syringe until the flexible arms  44   a ,  44   b  flex or bow outwardly to their “cocked” position and the needle  68  passes through the opening  86 . It has been found that the flexible arms  44   a ,  44   b  more reliably flex outwardly to the “cocked” position when there are extruded ribs  46  adjacent only the top edges of the arms rather than ribs adjacent both the top and bottom edges of the arms as in the Steyn safety needle device. 
     The user may then use the hand holding the syringe to also grasp the lever  48  thereby freeing the other hand of the user. Preferably, however, the user inserts the latch pin  76  into through hole  52  in the lever  48  to temporarily hold the flexible arms  44   a ,  44   b  in their outwardly flexed. “cocked” position with safety needle device  40  ready for use e.g., to administer an injection. As the user administers the injection, the distal end of the needle cup  80  engages the body of the patient and automatically unlatches the latching mechanism  72  by disengaging the pin  76  from the hole  52 . Upon withdrawal of the needle from the patient, the flexible arms  44   a ,  44   h  automatically return to their unflexed positions shown in  FIGS. 5-7  and the needle  68  and needle point  70  return to their “safe” positions inside the tubular member  44  and needle cup  80  as shown in  FIG. 7 . Should it occur upon withdrawal of the needle from the patient that the pin  76  re-engages the hole  52  in lever  48  and retains the arms in the “cocked” position, the hole  52  and/or the pin  76  may be arranged offset from the longitudinal axis of the device  40  so as to preclude such re-engagement. 
     After completion of the injection and return of the components to their “safe” positions, the user can then “disable” the device  40  by forcing the disabling pin  55  into bore  77  of the abutment  75 . This effectively prevents reuse of the device  40  and warns medical personnel that the device  40  has been used and should be discarded. Preferably, the disabling pin  55  and bore  77  are provided, respectively, with a mating annular ridge  57  and annular groove  79  that prevent removal of the pin  55  from bore  77  once it has been forced therein. 
     Alternatively, the device  40  may be disabled by a flexible elastomeric ring  81 , such as an O-ring, stretched about the distal end  50  of the tubular member  44  adjacent the needle cup flange  83 . After use and return of the device components to the “safe” position, the ring  81  may be rolled or shifted proximally to the approximate mid-point of the flexible arms  44   a ,  44   b  where it engages the notches  45  in the ribs  46  and positively prevents outward flexing of the arms and exposure of the needle point  70  through opening  86 . See ring  81 ′ shown in dashed lines in  FIG. 5 . Any mechanism that precludes or restrains one or both of the flexible arms  44   a ,  44   b  from bowing or flexing outwardly will effectively disable the device  40 . 
     Other embodiments of the lever and latching mechanisms will be apparent to those skilled in the art. For example, as shown in dashed lines in  FIG. 5 , an enlarged tab  90  may be affixed to the end of lever  48 , e.g., with pin  55 , to facilitate gripping of the lever  48 . One advantage of enlarged tab  90  is that it provides a larger surface area for the user to grasp and cock the device, i.e., by engaging the latch pin  76  with hole  52  or to hold against the barrel of a syringe. 
     Other arrangements for “cocking” the flexible arms  44   a ,  44   b  and “disabling” the device are also possible. For example, a pair of pins may be attached to the lever along its longitudinal axis and two small bores may be provided in the abutment into which one or the other of the pins may be inserted. The flexible arms  44   a ,  44   b  may be “cocked” as described above and a first pin inserted into a larger diameter first bore to retain the arms in their “cocked” position until it is automatically unlatched as described above. After the device  40  is used for an injection and the needle  68  automatically returns to its “sate” position, the device may be “disabled” by inserting the second pin into the second bore. To insure that the device  40  is permanently disabled, the second pin and second bore may be provided with interengaging annular serrations or the like to prevent the second pin from being removed from the second bore. 
     Other forms of latching and disabling mechanisms for holding the device  40  in the “cocked” position or “disabled” position are contemplated, and, in light of the foregoing description, will be apparent to those skilled in the art. 
     It is to be understood that the terms “initial,” “at rest” and “safe” are used herein to describe the initial state, position or condition of the arms  44   a ,  44   b  when the safety needle device  40  of the invention is removed from its sterile package, as well as the final state, position or condition of the arms immediately following use of the safety needle device when it is ready to be disabled and discarded. 
     Although a certain presently preferred embodiment of the invention has been described herein, it will be apparent to those skilled in the art to which the invention pertains that variations and modifications of the described embodiment may be made without departing from the spirit and scope of the invention. Accordingly, it is intended that the invention be limited only to the extent required by the appended claims and the applicable rules of law.