S&F Ref: 593894D2 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address Tyco Healthcare Group LP, of 15 Hampshire Street, of Applicant: Mansfield, Massachusetts, 02048, United States of America Actual Inventor(s): Mark Ferguson Mark Nelson Gale Thorne David Thorne Address for Service: Spruson & Ferguson St Martins Tower Level 35 31 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: Reaccessible Medical Needle Safety Devices and Methods The following statement is a full description of this invention, including the best method of performing it known to me/us:- REACCESSIBLE MEDICAL NEEDLE SAFETY DEVICES AND METHODS FIELD OF THE INVENTION This invention relates generally to safety devices for hollow bore medical needles and particularly to syringe needle devices which employ protective needle shields or 5 sheaths for securely shielding sharp needle tips, both before and after being used in a medical procedure. This invention more particularly relates to removable medical needle shields, sheaths or shrouds, which may be used as removable and replaceable protective needle covers, Consistent with such uses, the medical needle may be accessed, covered and reaccessed repeatedly for such purposes as protecting a sharpened needle tip in transit 10 before use, ad interim after a preliminary use, such as filling a syringe with a medication, and being displaced to a safety, needle-covering position after a medical procedure is completed. BACKGROUND OF THE INVENTION Problems associated with inadvertent needle sticks are well known in the art of 15 blood sampling, percutaneous medication injection and other medical -procedures involving use of medical needles. Ever increasing attention is being paid to needle stick problems due to the contemporary sensitivity of exposure to AIDS, Hepatitis and other serious blood-borne diseases. Prieedem involving removing a needle from a patient commonly require a 20 technician to use one hand to place pressure at the wound site where the needle is being withdrawn, while removing the needle apparatus with the other hand. It is common practice for an attending technician to give higher priority to care for the wound than is given to disposal of a needle. In the case of common non-safety devices, such priority either requires the convenience of an available sharps container within ready reach or 25 another means for safe disposal without leaving the patient's side. Providing adequate care, with accompanying safety procedures, is often compounded by the patient's physical condition and mental state (e.g., in bum units and psychiatric wards). Under such conditions, it is often difficult, if not impossible, to take the appropriate action to properly dispose of a used, exposed needle while caring for a patient. The common 2 practice of filling syringes with medication in one area and then transporting an uncapped needle to a patient area provides a significant opportunity for accidental needle sticks. Recapping a needle is currently discouraged in U.S. medical practice due to the dangers of accidental needle sticks associated with recapping. S The widespread knowledge and history associated with needle care and disposal problems have resulted in the numerous devices for preventing accidental needle sticks. Current devices for shielding syringe needles often require two hands, and with some devices the safety status of needle shields are not readily apparent, There is often a need to use syringe needles a plurality of times. When an 1o intramuscular injection is made, it is common practice to draw the contents from a drug, vial into a syringe and then inject the contents into a patient. It is desirable to use the same needle for penetrating a membrane on the drug vial and then for injecting the patient. However, the site where contents are drawn from the drug vial may be some distance from a site where the patient is to be injected, which may result in a technician's is recapping the needle for transport to the patient. Equally as concerning is another practice of carrying the needle unprotected, Some currently available safety devices permit covering and reaccessing a needle. However, factors such as those disclosed above have limited acceptance of these safety devices. There remains a need to provide a more satisfactory solution to a needle safety 20 device which is Reaccessible for multiple uses. Object of the Invention It is an object of the present invention to substantially overcome or at least ameliorate one or more of the disadvantages of the prior art, or to at least provide a useful alternative. AH21(2413646 1) KEH 3 Summary of the Invention There is disclosed herein a method for enclosing and reaccessing a sharpened medical needle comprising the steps of: (a) providing a safety apparatus for shielding the medical needle, said 5 apparatus comprising a hollow bore cannula securely affixed in a hub and having at least one sharpened tip to form the medical needle and a part hingedly joined to said hub, said part comprising an elongated shield which comprises a plurality of serially interconnected substantially rigid segments each of which is interconnected to at least one adjacent segment by an intersegment hinge, at least one segment comprising an open orifice, 10 through which said cannula passes to form an axis of intersection about the cannula, and a channel along which the cannula is disposed when the shield is linearly extended, said shield and said hinges being disposed to permit usable access to said sharpened tip in a medical procedure and extending of the shield to a substantially planar disposition along said cannula whereat the cannula is disposed along the channel, said shield further 15 comprising at least one releasable latching member which affixes the shield relative to the carmula, said shield and cannula, in combination, thereby forming a substantially rigid body which protectively encloses, without any portion of said shield contacting said sharpened tip, and denies access to said sharpened tip unless and until said releasable latching member is selectively actuated to permit refolding said shield and allowing 20 reaccess to said needle and sharpened tip; (b) displacing said shield about said hub and cannula into a compact, folded state such that said needle tip is accessible for a medical procedure; (c) at the end of a phase of said medical procedure unfolding and extending the shield about the needle and selectively actuating the releasable latching member; and 25 (d) reaccessing the needle by selectively releasing the releasable latching member and refolding the shield to the folded state. Preferably, the method for enclosing and reaccessing a sharpened medical needle comprises an additional step (c), Preferably, the method for enclosing and reaccessing a sharpened medical needle 30 comprises an additional step (d). AH21(2413646 1):KEH 4 Preferably, the method for enclosing and reaccessing a sharpened medical needle comprises additional steps of providing an unreleasable latch/catch mechanism. Preferably, the method for enclosing and reaccessing a sharpened medical needle comprises an additional step of selectively activating the unreleasable latch/catch 5 mechanism thereby disallowing further use of the needle and needle tip. Brief Description of the Drawings A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein: Figure 1 is a perspective view of a medical needle shield assembly with a needle 10 cover and a releasable needle shield. Figure 2 is a perspective view of the medical needle shield assemble of Figure 1 with the needle cover removed. Figure 3 is a perspective view of the medical needle shield assembly of Figure 2 with the shield partially displaced. is Figure 4 is a lateral cross section view of the medical needle shield assembly as seen in Figure 3. Figure 5 is a perspective view of the medical needle shield assembly of Figure 3 with the shield fully displaced to protectively cover the needle. Figure 6 is a lateral cross section view of the medical needle shield assembly as zo displaced in Figure 5. Figure 7 is a perspective view of a medical needle shield assembly which is substantially the same as the assembly of Figure 2 except that this assembly is seen without a needle and with an unreleasable catch and latch. AH21(2413646 1):KEH 5 Figure 8 is a lateral cross section view ofthe assembly shown in Figure 7 wherein areleasible catch and latch, that constrains the assembly in a stable folded state is shown. DETAILED DESCRIPTION OF THE INVENTION In this description, the term proximal is generally used to indicate relative 5 nearness of a referenced item to a user of a device or a viewer of a perspective drawing of a figure. The term distal is similarly used to indicate relative remoteness. Reference is now made to the embodiments illustrated in Figures 1-8 wherein like numerals are used to designate like parts throughout. In those cases where parts have similar, but not identical, form and function, numerals with primes may be used for ease in interpretative 10 cross referencing. Reference is now made to Figures 1-6 wherein a basic embodiment of the instant invention is disclosed. As shown in Figure 1, this embodiment is a needle shielding safety device 10. Device 10 is seen to have a needle cover 20 and a needle-hub-shield assembly 30. 15 Assembly 30 is also illustrated in Figure 2 wherein cover 20 is shown to be removed to expose a medical needle 40 and otherwise concealed distal portions of a foldable needle shield 50. As is apparent from differences between Figures 1 and Figure 2, needle cover 20 has an elongated hollow frustoconical distal part 60, which is similar in form and function to needle covers commonly used for protecting needles prior to use. 20 Cover 20 also has a laterally and proximally disposed guard 70. Guard 70 acts as a keeper against inadvertent unfolding or safety actuation of shield 50 before removal of cover 20 for use of needle 40. Similar to currently available needle covers, needle cover 20 may be formed (e.g., injection molded) from polypropylene, other synthetic resinous material, or equvalents thereof. 25 It is important to note that for devices which permit reaccessing a medical needle, a cover such as cover 20 may not be necessary. When a shield is securely, but releasibly latched, a device such as assembly 30 may be deployed in a safe state with a needle 40 being protectively covered by a shield, such as shield 50 in Figure 5. The device so deployed may then be packaged and shipped in an antiseptic protective wrap, such as a 6 "bubble pack" without a cover, such as cover 20. Such a deployment and elimination of a cover reduces both the cost of the basic device and the cost of discarding ancillary parts. In addition to needle 40 and shield 50, assembly 30 has a needle hub 80 to which needle 40 is securely affixed and to which shield 50 is hingedly affixed. In this 5 embodiment, hub 80 is seen to comprise a female luer fitting 90, though other flow through hub fitting and connections may be used within the scope of the instant invention. Needle 40 is generally formed from a hollow bore cannula to have an elongated shank 92 and a sharpened tip 100. Primary to the inventive novelty of this embodiment is shield 50. As may be 10 better seen in Figures 3 and 4, shield 50 is formed from two segments, a distal segment 110 and a proximal segment 120. It should be noted that more than two segments may be used to form a foldable needle shield. Distal segment 110 is made to have apair ofjuxtaposed elongated side pieces 122 and 124 and a closed end 126 which is formed to be contiguous with side pieces 122 and 15 124 and thereby form a hollow needle tip 100 guard recess 128. As shield 50 unfolds to protect needle 40 and needle tip 100, tip 100 should make no contact with any parts of distal segment 110. Such contact may jeopardize the structural integrity of tip 100 and, therefore, similarly jeopardize continuing use of needle 40. To assure that needle tip 100 is guided in and out of distal segment 110 in both cases where shield 50 is unfolded to 20 become a shroud and refolded to bare needle tip 100 for further use, a yoke 130 is affixed to side members 122 and 124 by a pair of hinges 132 and 134, respectively (see Figure 2). Yoke 130 has a needle bearing surface 136 upon which needle 40 glides as distal segment 110 rotates about needle 40 during folding and unfolding. As seen in Figure 6, distal segment 110 has an arcuately formed guide 138 disposed to provide a convex guide 25 surface 140 between needle 40 and needle bearing surface 136. In combination, yoke 130 and guide 138 act to deflect or lift needle 40 from guard recess 128 as shield 50 is folded and to guide needle 40 into guard recess 128 as shield is unfolded thereby protecting tip 100 from contact with shield 50. For these reasons, such combinations may be referenced as guides or bearings herein. .30 In addition, segment 110 has a pair of proximally disposed connective hinges 142 and 144 (see Figure 2) by which segment 110 is hingedly affixed to segment 120. It 7 should be noted that all or part of the hinges of assembly 30 may be formed as living hinges by injection molding all or any combination of parts of hub 80, proximal section 120 and distal section 110, if an appropriate material such as polypropylene is used. Also proximally disposed is a medially aligned transverse bar 146 which has a 5 sloped face 148 (see Figures 4 and 6). Sloped face 148 is so sloped to act as a catch for a latch disposed in proximal segment 120 and described in detail hereafter. Referring now to Figures 2-5, proximal segment 120 is shown to comprise a pair of lateral sides 152 and 154 joined by a top piece 156. As may be seen in Figures 5 and 6, sides 122, 124, 152 and 154 cooperate to form a channel 157 which acts as a protective 10 side guard for needle 40 and tip 100 when shield 50 is extended. Top piece 156 has a prominent button 158 superiorly disposed for easy digital access. Integral to button 158 is a distally extending arm 160, which terminates in an inwardly directed latch hook 162 (see Figure 6). Latch hook 162 has a proximally disposed latch face 164 (seen in Figure 4), which is disposed to interactively latch against a catch formed by sloped face 148 15 when shield 50 is completely unfolded. Also, integral with button 158 is a proximally extending arm 166 (see Figures 4 and 6). Arm 166 is bent at an elbow 168 to terminate in an inwardly extending cross member 170. Cross member 170 is transversely, securely affixed to lateral sides 152 and 154 (see Figure 3) in a cantilevered fashion such that retractive force applied to button 20 158 causes arm 160 to rotate upwardly and outwardly relieving the catch formed at faces 148 and 164. This permits shield 50 to be folded and thereby lift needle 40 from confinement of shield 50 for use in a medical procedure. As seen in Figure 5, proximal segment 120 is affixed to needle hub 80 by a pair of hinges 172 and 174 associated with lateral sides 152 and 154, respectively. Hinges 25 172 and 174 permit proximal segment 120 to rotate through an angle required to fold and unfold shield 50 about needle 40. As shield 50 folds and unfolds, distal segment 110 rotates about needle 40 in a manner dictated by the interface between yoke 130, needle 40 and arcuate guide surface 140. Yoke 130 is free to rotate by hinged attachment through hinges 132 and 134 (see Figures 3 and 5) as segment 110 rotates about needle 40. 30 In doing so, yoke 130 remains in alignment with needle 40 and provides a lift and guide as the segment rotates. In this manner, needle tip 100 is untouched by any structure of 8 shield 50. The displacement of needle tip 100 under the control of yoke 136 and arcuate guide surface 140 is best seen in combination in Figures 4 and 6. In Figure 5, shield 50 is fully unfolded and extended. A proximal and upward force placed upon button 158 causes shield 50 to unfold through the intermediate state 5 seen in Figures 3 and 4, and further to a completely folded state seen in Figure 2. A distal and arcuately downward force placed upon button 158 causes shield 50 to be displaced from the state seen in Figure 2 through the state of Figures 3 and 4, and further to the unfolded state of Figure 5. In this manner, needle tip 100 may be alternately protected by shield 50 and removed from shield 50 for use a plurality of times, with needle tip 100 10 being fully protected by an unfolded shield 50 between medical procedures. Following the last use of assembly 30 in a medical procedure, it is preferred that shield 50 be unreleasibly latched as a final precaution. An unreleasible latch or lock may be provided by anumber oflatching mechanisms within the scope ofthe instant invention disclosed herein. One such mechanism is seen as a part of assembly 30' in Figure 7. 15 With the exception of the following disclosed variations, assembly 30' is similar to assembly 30, earlier described, and, in the same manner, shield 50' is similar to shield 50. Shield 50' has a top piece 156' with a button 158, and a protruding latch part extends toward a lateral side 152' of a proximal segment 120' (Lateral side 152' is not shown in the figures, but is similar to lateral side 152 of proximal segment 120 of assembly 30 and 20 is referenced by the same number 152, with a prime.) Latch part 180 has the form of an arrow 182 having a pointed end 184 and a pair ofjuxtaposed ledges 186 and 188. Juxtaposed to pointed end 184, lateral side 152' has a slot 190, partially closed by a pair of ears 192 and 194. Ears 192 and 194 are spaced apart just far enough to permit total entry of arrow or barb 182 into slot 190 by distortion of ledges 186 and 188. Once 25 arrow 182 is so displaced into slot 190, the action of ears 192 and 194 against ledges 196 and 188, respectively, unreleasibly retain latch part 180 in slot 190. Such an unreleasible latch is accomplished by selectively applying a force upon button 158, which is sufficiently greater than the force to close and affix latch hook 162 of top piece 156' to a transverse bar 146 (see Figure 6). 30 It is also desirable to assure that shield 50'(and shield 50) is in a stable state when folded. Such assurance is achievable using a releasible latch as well as by friction. One 9 releasible latch is seen in Figure 8. In Figure 8, a laterally extending arm 166' of top piece 156' ends in a "j" section 200 having a sloping face which forms a latch 202. To form a catch for latch 202, hub 80' has an outward extending excrescence 210 to form a catch 212. Note, that, when assembly 30' is folded, latch 202 and catch 212 retain shield 5 50' in a stable, folded state. However, by placing sufficient distally directed force upon button 158, arm 210' is deflected to release latch 202 from catch 212 permitting shield 50' to unfold and protectively cover needle 40 and needle tip 100. The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be 10 considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.