WO1999051289A1

WO1999051289A1 - Needle stick protection apparatus

Info

Publication number: WO1999051289A1
Application number: PCT/AU1999/000250
Authority: WO
Inventors: Bruce Leigh Kiehne
Original assignee: Jireh Tech Pty. Ltd.
Priority date: 1998-04-01
Filing date: 1999-04-01
Publication date: 1999-10-14
Also published as: EP1067977A1; EP1067977A4; CN1302214A; JP2002510534A; CA2329780A1

Abstract

This invention relates to a needle stick protection apparatus including a shield (30) having an internal through bore which is capable of receiving the barrel of a syringe (10), said bore including a spline (32) or a rib which extends along part of the length of said bore and wherein there is provided a discontinuity (33) in said spline which is adapted to receive a portion (57) of a locking member (50) that is associated with the syringe and which extends laterally beyond the barrel, said discontinuity being aligned with an aperture (34) formed in a side wall of said shield.

Description

1 NEEDLE STICK PROTECTION APPARATUS

This invention relates to needle stick protection apparatus. This invention has particular but not exclusive application to needle stick protection apparatus for protecting persons from needle stick injuries caused by hypodermic needles, and for illustrative purposes reference will be made to such application. However it is to be understood that this invention could also be used to prevent repeated use of hypodermic needles. syringes typically include a tubular body or barrel having a narrow outlet associated with one end thereof which fluidly communicate with an externally located nozzle to which a hypodermic needle or such like is or may be selectively connected. The opposite end of the barrel may include a finger abutment such as a pair of opposing, outwardly directed, flanges and wherein the syringe may further include a piston which may be used to eject fluids stored in the barrel through the nozzle.

Syringes fitted with a hypodermic needle are often used to inject medications and other fluids into the bloodstream of people and animals, syringes fitted with a hypodermic needle are also used to withdraw fluids, including blood from the bloodstream of people and animals.

As a consequence of use the hypodermic needle in particular may become contaminated with various 2 contagious micro-organisms including those associated with diseases such as AIDS (Acquired immune Deficiency Syndrome), hepatitis, tetanus and tuberculosis.

Contagious micro-organisms, such as those referred to above, can be transferred from an infected person to another by the repeated use by others of contaminated hypodermic needles or due to the needle accidentally piercing a person's skin, such as may occur amongst persons involved in health care industries when handling syringes. in order to prevent needle stick injuries and/or the repeated use of hypodermic needles, numerous tubular shields have been devised by others which are intended to be slidably mounted on the body of a syringe and moveable between an inoperative position, wherein the pointed end of the needle is exposed, and an operative position, whereby the pointed end of the needle is surrounded by the free end of the shield. Several examples of shields are disclosed in us Patent No. 5,595,566 (Vallelunga, January, 1997).

The shields typically include a bore having an internal groove which is adapted to receive a portion of a locking member mounted on the syringe. The shields are typically manufactured by an injection moulding process and wherein a separate tool is subsequently used to cut a circumferential groove in the cylindrical internal surface of the bore. The creation of the internal groove is a complex operation and involves additional handling of the shield. 3

Consequently the manufacture of the shield is rather expensive. in order to overcome the problems associated with the production of an internal groove, shields manufactured for use with syringes produced by Becton Dickinson include a plurality of internal projections which act as abutments. These abutments are both evenly and closely spaced around the circumference of the tube. The abutments are further arranged in a staggered relationship on either side of an imaginary circumferential band and wherein the region separating the adjacent abutments is adapted to receive a flange like locking member mounted on the syringe. while the manufacture of such shields may be less complex than those previously described, the manufacturing process requires the use of two cores which are retracted through opposing ends of the shield. Accordingly, the internal diameter of the opening associated with the free end of the shield, which in use surrounds the pointed end of the needle, must be larger than the diameter of the circumferential flange of the locking member which extends beyond the external surface of the syringe body, AS a consequence the internal diameter of the free end of the shield is large enough that persons can insert a fingertip into the shield and thereby risk pricking themselves. This could be particularly hazardous if inquisitive children were to come across a needle protected by such apparatus. 4

To overcome this problem, Becton Dickinson currently provide a cap which can be secured to the free end of the shield if so desired. However, it will be appreciated that placement of the cap itself on the end of the shield may lead to a person pricking themselves. in addition, it has been noted that the strength provided by the closely spaced abutments to the surrounding wall portion of the shield inhibits deformation of same arising from the sliding engagement of the flanged locking member with the abutments. As a consequence there exists considerable resistance to the sliding movement of shield relative to the locking member in the vicinity of the projections and wherein persons, because of this, do not always manage to pull the body of the syringe far enough back relative to the shield so that the flange of the locking member is retained between adjacent obliquely opposing abutments.

It has also been observed that the locking member retai ned between the obli quely spaced abutments can be easily dislodged by applying a force to the free end of the shield in the general di rection of the syringe. As a consequence both the needle and the syringe may be re-used or, if discarded, may accidentally injure others .

Furthermore, many of the shields herein before described can not be used in conjunction with existing syringes of the type referred to above without some modifications being made to the syringes. The 5 modifications, such as the addition of an external flange, typically involve the alternation and/or replacement of existing dies or tools and/or additional handling during the manufacturing process which is expensive, time consuming and may at least temporarily disrupt the supply of syringes.

It has also been noted that movement of the shields between an inoperative and an operative position requires the use of two hands. Typically the shield is held in one hand while the person's other hand is used to hold the syringe.

It is noted that persons involved in the performance of many surgical procedures are required to administer drugs using hypodermic needles and that their hands, which are often covered with body fluids such as blood, are usually very slippery. AS a consequence their hands often slip over the shield they are trying to manipulate and accidently engage the sharp end of the hypodermic needle. it has been observed that person's who use hypodermic needles often use the fingers of one hand to hold the skin surrounding the point of entry of the needle in order to minimise any damage caused to same when piercing the person's skin or extracting the needle. A shield which could be operated using one hand and which may be used to shroud the needle as it is extracted from a person's skin would be most desi rable.

The present invention aims to alleviate one or 6 more of the above disadvantages and to provide needle stick protection apparatus which will be reliable and efficient in use.

With the foregoing in view this invention in one aspect relates to needle stick protection apparatus including: a shield having an internal through bore which is capable of receiving the barrel of a syringe, said bore including a spline or rib in which there is formed a discontinuity which is adapted to receive a portion of a locking member associated with the syringe and which extends laterally beyond the barrel. in another aspect this invention relates to needle stick protection apparatus including: a shield having an internal through bore which is capable of receiving the barrel of a syringe, said bore including a spline or rib which extends along part of the length of said bore and wherein there is provided a discontinuity in said spline which is adapted to receive a portion of a locking member that is associated with the syringe and which extends laterally beyond the barrel, said discontinuity being aligned with an aperture formed in a side wall of said shield. preferably the discontinuity is formed during a moulding process by a member which is retracted through the aforementioned aperture formed in the side wall of the shield. preferably the shield includes a plural ity of ci rcumferentially spaced splines in which there are 7 each formed a discontinuity which is aligned with a respective aperture formed in a side wall of the shield and wherein said discontinuities are laterally aligned within said shield. The splines may extend along much of the length of the shield or selected portions thereof.

The splines of the shield are preferably adapted to frictionally engage the locking member and wherein resistance to the sliding motion of the locking member relative to the shield is partly reduced by the ability of the shield, or selected portions thereof to change its shape. More particularly, at least some of the splines may be separated by a wall portion which can be readily and resiliently deformed. For example the shield may be constructed from a resiliently deformable plastics material such as a high density polypropylene, and wherein the wall portion may be of thin construction when compared with the combined thickness of a side wall and a spline of the shield. in some embodiments the bore may include a small number of splines, such as two or three splines, which are evenly spaced around the circumference of the bore and wherein each of the splines are separated by a resiliently deformable wall portion. in other embodiments, the bore may include discrete groups of splines and wherein the groups may be evenly spaced around the circumference of the bore.

Adjacent groups of splines are preferably separated by a resiliently deformable wall portion and wherein the 8 circumferential spacing separating adjacent groups is preferably larger than the circumferential space occupied by a group of splines. For example, in the preferred embodiment the bore may include two opposing pairs of splines and wherein the circumferential spacing separating each pair of splines is greater than the circumferential space occupied by either pair of splines.

The shield may also include external gripping means which persons may use to assist them to hold the shield, particularly when attempting to position the shield in an operative position. The gripping means may include a roughened surface, such as a knurled surface. Alternatively, the gripping means may include one or more ribs which may extend around at least part of the external side wall of the shield. Futhermore, the gripping means may be located in the vicinity of the discontinuities. For example, in the preferred embodiment the shield includes two external annular ribs or flanges located on either side of the apertures formed in said shield. in another aspect, this invention relates to a method of manufacturing a shield of the type having an internal through bore which is capable of receiving the barrel of a syringe, said bore including a spline which extends along at least a portion of the shield and wherein the spline includes a discontinuity, the discontinuity being adapted to receive a portion of a locking member associated with the syringe, said method 9 including: providing two blocks each having an abutment surface in which there is formed a cavity which complements the external shape of the shield to be produced and wherein the discontinuity is formed by a projection extending outwardly from one of said cavities; providing a primary core which compliments the internal shape of the shield to be produced, said primary core having a channel which complements the shape of the spline; placing the two blocks together such that the two abutting surfaces abut and wherein the cavities cooperate to form a bore and the primary core is supported within said bore and a free end portion of the projection is received within and engages the surfaces of the channel of the primary core; injecting a settable plastics material into the bore via a runner communicating with the bore; parting the two blocks, and stripping the plastics shield from the core. in still yet another aspect, this invention relates to a method of manufacturing a shield of the type having an internal through bore which is capable of receiving the barrel of a syringe, said bore including a spline which extends along at least a portion of the shield and wherein the spline includes a discontinuity, the discontinuity being adapted to receive a portion of a locking member mounted on the 10 syringe, said method including: providing two blocks each having an abutment surface in which there is formed a cavity which complements the external shape of the shield to be produced; providing a primary core which compliments the internal shape of the shield to be produced, said primary core having a channel which complements the shape of the spline and a pin which may be selectively extended into said channel so as to form a discontinuity in the spline; placing the two blocks together such that the two abutting surfaces abut and wherein the cavities cooperate to form a bore and the primary core is supported within said bore and the pin blocks off a portion of the channel; injecting a settable plastics material into the bore via a runner communicating with the bore; parting the two blocks; retracting the pin, and stripping the plastics shield from the core. in yet another aspect, this invention relates to a needle stick protection apparatus which when assembled can be mounted on a syringe of the type which includes a tubular body or barrel having a cylindrically shaped side wall and a narrow opening formed in an end wall which fluidly communicates with an externally located nozzle to which a hypodermic needle may be selectively operatively connected, said 11 needle stick protection apparatus including: a sleeve like shield mountable on the barrel portion of the syringe such that it can move between an inoperative position wherein the exposed pointed end of the hypodermic needle may be used to pierce a person's skin and an operative position wherein accidental contact of the pointed end of the hypodermic needle with a person's skin is obstructed by said shield, said shield being provided with an internal discontinuity located intermediate it's opposing end portions; a locking member located inside said shield and which is capable of movement relative to said shield, said locking member being provided with mounting means for mounting the locking member on the syringe, said locking member having an edge portion which when located in said discontinuity assists with the retention of said shield in an operative position, said edge portion being adapted to extend outwardly from the syringe in a generally lateral direction beyond the cylindrical side wall of the syringe, and retaining means located inside said shield for retaining said locking member on the syringe.

The shield is preferably manufactured from a resiliently deformable plastics material and is generally of the type previously described above. Preferably the discontinuity is a break formed in a spline that extends along at least part of the internal bore of the shield. Preferably the discontinuity is aligned with an aperture formed in a side wall of the 12 shield. Preferably the discontinuity is formed during a moulding process by a member that is subsequently retracted through an aperture in a side wall of said shield. The shield preferably includes locating means associated with one end thereof which is adapted to receive or abut against the locking member during the process of mounting the locking member on the syringe. For example, the locating means may include a seat or annular flange associated possibly with a constriction formed in one end portion of the shield. Alternatively, the locating means may include a plurality of abutments, which may be evenly spaced around the internal wall of the shield, against which the locking member may abut.

The locking member preferably includes an aperture or bore through which a part of the syringe may extend such as the barrel or the nozzle. For example, the locking member may be a washer and wherein the washer may be manufactured from a resiliently deformable material and includes a mounting aperture to receive the nozzle. Alternatively the washer may be a split washer thereby allowing the compression and expansion of same as may be required in order that it may pass over any internal restrictions associated with the interior of the shield and to expand into the discontinuity.

Preferably the washer when mounted on the nozzle leaves a substantial portion of the nozzle exposed and 13 free for engagement with a hub of a hypodermic needle, in an alternative embodiment the locking member may include a body having an outwardly, laterally extending portion adapted to engage the discontinuity in the shield, such as an outwardly directed annular flange, and a bore adapted to receive the nozzle of the syringe.

The body may also include securing means for securing the hub of a needle to the locking member, in one embodiment the securing means may be adapted to selectively releasably attach the hypodermic needle to the locking member. However in other embodiments the securing means may be adapted to engage the hypodermic needle in a manner whereby considerable force would need to be used so as to separate the hypodermic needle from the locking member. For example, the securing means may include a recess adapted to receive the hub of the needle and attachment means associated with said recess for maintaining the hub of the needle attached to the recess. The attachment means may include a plurality of inwardly directed projections, such as a plurality of barbs, flanges or a threaded portion, behind which a flange or edge portion of the hub may be operatively retained. in some embodiments the locking member may also include a connecting portion adapted to fluidly connect, or assist with the fluid connection of, the nozzle of the syringe to the hub of the needle. For example, the connecting portion may be surrounded by 14 the aforementioned recess and may be adapted to frictionally locate within the hub of the needle. The connecting portion preferably communicates with the bore in which the nozzle of the syringe is located. in one embodiment the retaining means may be integral with or attached to the locking member and may be adapted to engage an adjacent portion of the syringe such as the barrel or the nozzle. For example the retaining means may include one or more barb like projections associated with the interior of the aperture or bore. in another embodiment the retaining means may include a portion of the locking member which is adapted to threadably engage a threaded portion of the syringe. in still yet another embodiment the retaining means may include a portion of the locking member which is adapted to we wedged between opposing portions of the syringe. However it will also be appreciated that in other embodiments the retaining means may include various combinations of features referred to above. For example, the portion of the locking member to be wedged between opposing portions of the syringe may further include one or more barbs which shall engage a surface of the syringe.

Alternatively, the retaining means may include a retaining washer which may by way of example be mounted on the nozzle and wherein the washer includes an 15 aperture having one or more inwardly directed barbs or such like which are adapted to engage the nozzle when the nozzle extends through said aperture.

Preferably, the forces required to displace or overcome the retaining means such that the locking member may be separated from the syringe are greater than the forces exerted by the shield on the locking member when moving the shield between an inoperative position and an operative position. in yet another aspect this invention relates to a method of attaching needle stick protection apparatus of the type described above to the nozzle of a syringe including: providing an assembled needle stick protection apparatus, inserting the barrel of the syringe into the shield such that the locking member is located on the syringe and is retained on the syringe by engagement of the syringe with the retaining means. in yet another aspect this invention relates to a method of using needle stick protection apparatus of the type described above so as to avoid needle stick injuries, the needle stick protection apparatus being mounted on a syringe which is operatively connected to a hypodermic needle, said method including: shielding the pointed end of the hypodermic needle by movement of the shield relative to the needle such that the needle is enclosed by the shield and is retained in an operative shielding position by the 16 engagement of a portion of the locking member with the discontinuity in the shield. in will be appreciated that a user may shield the hypodermic needle by moving the shield towards the needle.

Alternatively, in order to shield the needle, the user may elect to hold the shield stationary in their hand while drawing the syringe and the attached needle towards the shield. However preferably while the pointed end of the needle is embedded below a person's skin, the shield is moved towards the needle such that the end of the shields abuts against the person's skin. Then, while holding the shield against the person's skin, the needle is drawn into the shield. As consequence the pointed end of the needle is not exposed and wherein the potential for accidental contact with same is avoi ded . in yet another aspect this invention relates to a locking member which may be mounted on a syringe, said locking member including: an outwardly directed side portion which extends beyond the barrel of the syringe when the locking member is mounted on the syringe; mounting means for mounting the locking member on the syringe; retaining means associated with the locking member which inhibits separation of the locking member from the syringe, and 17 securing means for securing a hub of a hypodermic needle to the locking member characterised in that the hub of the needle while secured to the locking member is able to communicate with a nozzle of the syringe. Preferably the mounting means includes a through bore which is adapted to receive a portion of the syringe such as either the barrel or the nozzle.

The retaining means may include an internal threaded portion of the bore which may be adapted to engage a complementary threaded portion of the syringe, such as a threaded nozzle or a threaded barrel. Alternatively the retaining means may include one or more barbs associated with the bore and which in use shall engage either the barrel or the nozzle of the syringe.

The securing means may include a recess adapted to receive the hub of the needle. The recess may include an internal threaded portion which is adapted to threadably engage an edge portion of the needle hub. Alternatively the recess may include one or more projections which extend into the interior of the recess and which can be displaced by the hub of the hypodermic needle during the location of the hub within said recess and behind said projections. However it is preferred that the projections will resist attempts by persons to remove the hub from the recess, in other embodiments the recess may include one or more abutments which extend into the interior of the recess and behind which an edge portion of the hub may be 18 retained. The recess may further include guides and stops to assist with the operative location of the edge portion behind the flanges. in some embodiments the locking member may also include connecting means adapted to fluidly connect the nozzle to the hub of the needle. For example, the connecting means may include a connecting portion surrounded by the aforementioned recess and which is adapted to frictionally locate within the hub of the needle. The connecting portion preferably communicates with the bore in which the nozzle of the syringe is located.

The locking member is preferably used in conjunction with a shield of the type described above. For example, shields containing the locking member may be provided for subsequent attachment to a syringe of the type consisting of a cylindrically shaped, tubular body or barrel having a narrow outlet associated with one end thereof which fluidly communicates with an externally located nozzle to which a hypodermic needle may be selectively attached. in still yet another aspect this invention relates to a needle stick protection apparatus which may be used in conjunction with a syringe of the type which includes a tubular body having a narrow outlet associated with one end thereof which fluidly communicates with a nozzle to which a hypodermic needle is or may be selectively connected, a finger abutment associated with the other end of the body and a piston, 19 said needle stick protection apparatus including: a tubular shield mountable on the body of the syringe and moveable between an inoperative position, wherein the pointed end of the needle is exposed, and an operative position, whereby the pointed end of the needle is surrounded by the free end of the shield, and finger engagement means associated with said shield, characterised in that, while the body is supported between two fingers of a user's hand that bear against the finger abutment, movement of said shield between an inoperative position and an operative position may be effected by applying pressure to said finger engagement means using the user's thumb of the same hand. The finger engagement means may be located on or near a portion of the shield which lies adjacent the finger abutment of the syringe when the shield is mounted on the syringe. in one embodiment the finger engagement means may simply include a surface of the shield which is roughened, such as a knurled surface, or a portion of the shield which includes one or more surface irregularities, such as a tread pattern or a plurality of ribs. in an alternative embodiment the finger engagement means may include a depression formed in a wall portion of the shield and wherein the depression may be adapted to receive a portion of the user's thumb. As a consequence the shape of the depression 20 may compliment the shape of the user's thumb. in yet another embodiment the shield may include a flange or guard which extends outwardly from the shield and possibly toward the finger abutment of the syringe. The shield may also include locating means or guide means which enable the user when mounting the shield on the syringe to position the finger engagement means such that it lies to one side of the finger abutment. For example, the locating means may include an abutment on the shield against which the finger abutment abuts when correctly positioned relative to the shield. in another aspect, this invention relates to a method of using needle stick protection apparatus of the type described above so as to avoid needle stick injuries, the needle stick protection apparatus being mounted on a syringe which includes a tubular body having a narrow outlet associated with one end thereof which fluidly communicates with a nozzle to which a hypodermic needle is or may be selectively connected, a finger abutment associated with the other end of the body and a piston, said method including: supporting the syringe between two fingers of a user's hand such that the fingers bear against the finger abutment; placing the user's thumb of the same hand against the engagement means, and moving the shield relative to the syringe such that the pointed end of the needle is surrounded by the 21 shield, said movement being effected by pressure applied to the engagement means and the finger abutment by the thumb and fingers respectively. in order that this invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherein:

Figure 1 is a side view of a typical syringe; Figure 2 is a side view of a typical hypodermic needle;

Figure 2a is a schematic plan view of the hub of the hypodermic needle illustrated in figure 2;

Figure 3 is a side view of the syringe illustrated in figure 1 and wherein the figure also shows the hypodermic needle illustrated in figure 2 attached to said syringe;

Figure 4 is a side view of a shield constructed in accordance with the present invention; Figure 5 is an end view of the shield illustrated in figure 4;

Figure 6 is another end view of the shield illustrated in figure 4;

Figure 6a is a pictorial view of one end of the shield illustrated in figure 4;

Figure 7 is a cross-sectional side view of the shield illustrated in figure 4;

Figure 8 is a plan view of a locking member constructed in accordance with the present 22 invention;

Figure 9 is a side cross-sectional view of the locking member illustrated in figure 8; Figure 10 is a side cross-sectional view of the needle stick protection apparatus illustrated in figure 4;

Figure 11 is a side cross-sectional view of the needle stick protection apparatus illustrated in figure 4 when mounted on the syringe illustrated in figure 3, said protection apparatus being shown in its inoperative position; Figure 12 is a side cross-sectional view of the needle stick protection apparatus illustrated in figure 4 when mounted on the syringe illustrated in figure 3, said protection apparatus being shown in its operative shielding position; Figure 13 is a schematic side view showing the needle stick protection apparatus illustrated in figure 4 prior to mounting said protection apparatus on a syringe;

Figure 14a is a schematic side view showing the needle stick protection apparatus illustrated in figure 4 mounted on the syringe; Figure 14b is a schematic end view showing the needle stick protection apparatus illustrated in figure 4 mounted on the syringe; Figure 15 is a schematic side view showing the needle stick protection apparatus illustrated in figure 4 mounted on the syringe prior to the 23 attachment thereto of a hypodermic needle; Figure 16 is a schematic side view showing the needle stick protection apparatus illustrated in figure 4 mounted on the syringe with the needle attached;

Figure 17 is a schematic side view showing the needle stick protection apparatus illustrated in figure 4 mounted on the syringe with the needle attached and the cap removed; Figure 18 is a schematic side view showing the needle stick protection apparatus illustrated in figure 4 mounted on the syringe with the needle attached; Figure 19 is a schematic side view showing the needle stick protection apparatus illustrated in figure 4 mounted on the syringe with the needle attached and showing the shield in an operative shielding position; Figures 20 and 21 each show a schematic side view showing the needle stick protection apparatus illustrated in figure 4 mounted on the syringe, with the needle attached, the syringe being loaded ready for use; Figure 22 is a schematic side view showing the needle stick protection apparatus illustrated in figure 4 mounted on the syringe, with the needle attached, and the contents of the syringe having been dispensed; Figures 23 and 24 each show a schematic side view 24 showing the needle stick protection apparatus illustrated in figure 4 mounted on the syringe, with the needle attached, the shield having been moved from an inoperative position (figure 23) to an operative position (figure 24);

Figure 25 is a schematic side view of the locking member operatively retained within discontinuities associated with the shield;

Figure 26 is a schematic side view showing the syringe having been separated from the needle stick protection apparatus illustrated in figure

4 and the hypodermic needle retained within said protection apparatus;

Figure 27 is a plan view of an alternative locking member constructed in accordance with the present invention;

Figure 28 is a side cross-sectional view of the locking member illustrated in figure 27;

Figure 29 is a side view of another syringe; Figure 30 is an enlarged side cross-sectional view of the nozzle of the syringe illustrated in figure 29;

Figure 31 is a side view of a typical hypodermic needle; Figure 32 is a side cross-sectional view of a locking member constructed in accordance with the present invention;

Figure 33 is a plan view of the locking member illustrated in figure 32; 25 Figure 34 is a side cross-sectional view of the locking member shown mounted on an end portion of the syringe;

Figure 35 is a side view of a shield constructed in accordance with the present invention;

Figure 36 is an end view of the shield illustrated in figure 35;

Figure 37 is another end view of the shield illustrated in figure 35; Figure 38 is a side cross-sectional view of the shield illustrated in figure 35; Figure 39 is a side cross-sectional view of a needle stick protection apparatus constructed in accordance with the present invention; Figure 40 is a side cross-sectional view of the needle stick protection apparatus illustrated in figure 39 when mounted on the syringe illustrated in figure 29, said protection apparatus being shown in its noperative position, and Figure 41 is a side cross-sectional view of the needle stick protection apparatus illustrated in figure 39 when mounted on the syringe illustrated in figure 29, said protection apparatus being shown in its operative shielding position. Figure 1 shows a typical syringe 10 manufactured from a clear plastics material. The syringe 10 includes a cylindrically shaped, tubular body or barrel 11 having a narrow outlet associated with one end 12 thereof which fluidly communicates with an externally 26 located nozzle 13 to which a hypodermic needle 14 may be selectively attached. The external surface of the nozzle is tapered and wherein the taper is commonly referred to as a uer taper. The other end of the barrel 11 includes a finger abutment 9 consisting of two opposing, outwardly directed flanges 8.

The syringe 10 also includes a piston 15 having a head portion 16 which is seal ably located within the barrel 11 and wherein the piston 15 is used to force fluids which are stored in the barrel 11 through the nozzle 13.

The hypodermic needle 14 illustrated in figure 2 includes a hollow, substantially conically shaped, hub 17 surrounding a lower or basal portion 18 of a tubular needle 19 having a pointed end 20. The hub 17 typically includes a substantially conically shaped recess 21 which is adapted to receive the nozzle 13 and to frictionally engage therewith, as illustrated in figures 3 and 9. The hub 17 also includes a substantially ell ipti cally shaped flange 5 having opposed end portions 6.

The syringe 10 and the hypodermic needle 14 are typically provided in separate packages and wherein the pointed end 20 of the needle 14 is usually protected by a removable sheath or cap, not shown.

Figures 4 to 7 show a substantially cylindrical shield 30 which is mountable on the barrel 11 of the syringe 10. The shield 30 s preferably manufactured 27 from a clear plastics material which is resiliently deformable, such as a high density polypropylene material .

The shield 30 incudes an internal bore 31 which is open at both ends. The bore 31 includes a main or body portion 44 having an internal diameter which is slightly larger than the external diameter of the barrel 11 of the syringe 10.

The bore 31 includes two pairs of parallel splines 32 which extend longitudinally along much of the length of the body portion 44 and wherein the pairs of splines are equally spaced from one another. Furthermore, it is preferred that the two splines 32 which make up each pair of splines 32 are closely spaced together and that the circumferential space occupied by any one of the pairs of splines is much smaller than the circumferential distance separating the pairs of splines. AS a consequence the wall portion 45 separating the pairs of splines 32 is easily deformed. It is also preferred that the distance separating diametrically opposing splines 32 is preferably slightly greater than the external diameter of the barrel 11 of the syringe 10.

The splines 32 are broken part way along their length by a discontinuity 33 and wherein the aligned discontinuities form in affect an internal annular groove 33a. Each discontinuity 33 in the splines 32 also communicates with an aperture 34 formed in a side wall 35 of the shield. 28

The apertures 34 are surrounded by two external , lateral ly extending, annular ribs 36 and 37. Opposite each rib 36 and 37 there exists an internal , shal l ow, depression 38 and 39 respectively formed in the splines 32.

The shield 30 also includes a cylindrical end portion 40 having an internal diameter which is smaller than the internal diameter of the opposing end portion

41 and the external diameter of the barrel 11. The end portion 40 includes four internal, evenly spaced, ribs

42 which help strengthen said end portion as well as eight adjacent ribs 43 which extend longitudinally along a small portion of the body portion 44 of the shield. The shield 30 also includes finger engagement means 100 including a flange 101 which extends outwardly therefrom as illustrated in figure 6a. The rear edge 102 of the flange 101 forms an abutment against which the finger abutment 9 of the syringe may abut.

The shield 30 is preferably manufactured by an injection moulding process and wherein the mould preferably includes two blocks in which there are each formed a cavity having a shape which compliments the external shape of the shield 30. The mould also includes a substantially cylindrical core located intermediate the cavities of the assembled blocks and wherein the shape of the core compliments the internal shape of the shield 30. Each of the apertures 34 and 29 the communicating discontinuity 33 are formed by a respective projection associated with one or other of the cavities and which is configured so as to engage the core. A runner communicating with one or other of the cavities is used to supply the interior of the mould with sufficient molten plastics material to construct the shield and wherein when the plastics material has set, the resulting shield 30 is stripped from the core. The depressions 38 and 39 are formed as a consequence of the slow rate by which the plastics material comprising the ribs 36 and 37 cool when compared with adjacent thinner wall portions.

Figures 8 and 9 show a locking member 50 manufactured from a plastics material. The locking member 50 includes a substantially cylindrical body portion 51 and an external annular flange 57 having an external diameter which is slightly larger than both the external diameter of the barrel 11 and the distance separating diametrically opposing splines 32. it is also preferred that the height of the locking member generally indicated by arrows 58 is less than the distance separating diametrically opposing splines 32.

The locking member 50 also includes a centrally located internal bore 52 defined by a continuous wall 53 having a taper which corresponds to the taper of the nozzle 13 of the syringe 10. The wall 53 includes a plurality of inwardly directed barbs 54. The bore 52 communicates with a centrally located recess 55 which includes a plurality of inwardly and downwardly 30 directed projections 56.

It is envisaged that the shield 30 and the locking member 50 will be provided to prospective users in an assembled state ready for use as a needle stick protection apparatus 60, as illustrated in figure 10, which can be selectively mounted on an existing syringe 10 prior to the attachment thereto of a hypodermic needle 14. The locking member 50 is preferably placed in the bore 31 of the body portion 41 of the shield 30 and wherein a tool is used to push it along the shield until it lies adjacent the restricted end portion 40, as illustrated in figure 10. Preferably the annular flange 57 abuts against the end portions 61 of the ribs 43. in use, the needle stick protection apparatus 60 shall be mounted on the barrel 11 of a syringe 10 by inserting the barrel 11, nozzle first, into the bore 31, as illustrated in figure 13. The nozzle 13 is preferably driven into the bore 52 of the locking member 50 such that the tapered wall 53 and the external wall of the nozzle frictionally engage one another, as illustrated in figure 14a. The locking member 50 is further retained on the nozzle 13 by the engagement of the barbs 54 and the external wall of the nozzle.

Preferably the finger abutment 9 lies adjacent the finger flange 101 and wherein a side edge portion 7 of the finger abutment and the abutment 102 abut, as illustrated in figures 14a and 14b. 31

The hub 17 of the hypodermic needle 14 in turn may be pushed against the projections 56 so as to temporarily displace same and may be secured to the nozzle 13 by the frictional engagement of the external wall of the nozzle and the tapered side wall of the conically shaped recess 21, as illustrated in figure 15.The cap 90 covering the needle may then be removed, as illustrated in figure 17.

The resulting syringe and needle assembly preferably resembles the assembly 70 illustrated in figures 11 and 17.

It will be noted that the shield 30 is in it's inoperative position and wherein a significant portion of the needle 19 including the pointed end 20 is exposed.

Fluid may be drawn into the barrel of the syringe via the hypodermic needle 19 by immersing the pointed end 20 in the fluid and drawing the piston 15 back, as illustrated in figure 18. If the needle is not to be used immediately to inject a person with the fluid contained in the barrel 11, the shield 30 may be moved between its extreme inoperative and operative positions such that the pointed end of the needle 20 is surrounded by the end portion 40, as illustrated in figure 19. However, the shield 30 can still be retracted or returned to its extreme inoperative position as illustrated in figure 20 so that the user may inject the contents of the syringe into a patient when desired. 32 Fluid contained in the barrel 11 may be injected into a person's bloodstream by piercing a person's skin with the pointed end 20 of the needle 14 and by pushing against the free end 6 of the piston 15 with the user's thumb 120 while supporting the syringe 10 between the user's two fingers 121 which bear against the finger abutments 8.

Having administered the injection, the shield 30 may be slid along the barrel 11 such that the end portion 40 of the shield bears against the person's skin. Then, while holding the end portion 40 against the person's skin, the needle 19 may be removed from beneath the person's skin and subsequently housed within the shield 30. Due to the frictional engagement of the annular flange 57 with the splines 32, movement of the shield 30 relative to the barrel 11 shall cause some localised deformation of the shield but wherein it is believed that some of the resistance to said movement is at least partially overcome by the flexibility of the wall portions 45. when the annular flange 57 is aligned with the depressions 38, the flange 57 shall engage the depressions 38 and wherein an audible sound signifying said engagement may be heard. Because the depressions 38 are rather shallow the flange 57 and the depressions 38 may be easily disengaged thereby allowing the user to extend the pointed end 20 of the needle beyond the confines of the shield thereby enabling the assembly to 33 be used a second time to inject or extract fluids if so desired. This may be important where for example it is proposed to use the syringe to inject a person with small amounts of the fluid housed therein at different stages during a medical procedure but wherein it is desirous that the pointed end 20 of the needle is temporarily shielded by the end portion 40 when the assembly 70 is not being used.

However if the syringe 10 is not be to used again, the shield 30 may be placed in it's operative shielding position by aligning the annular flange 57 with the discontinuities 33 such that the flange 57 may be retained therein by the obstacles posed by the opposing edges 75 of the respective splines 32, as illustrated in figure 12. A second audible sound signifying engagement of the annular flange 57 in the discontinuities may also be heard. The sighting of the annular flange 57 through the apertures 34 will also provide a visual means of ascertaining whether the flange 57 is retained in the discontinuities 33.

Relative movement of the shield 30 and the syringe 10 is preferably effected using one hand, namely by supporting the syringe 10 between the two fingers 121 such that the fingers 121 bear against the finger abutment 8 while placing the thumb 120 against the finger flange 101, and by applying pressure to the finger flange 101 and the finger abutment 8 by the thumb 120 and fingers 121 respectively, as illustrated in figures 23 and 24. 34 This then allows the person performing the injection to use the fingers of their other hand to hold the patient's skin that surrounds the point of entry of the needle 14. it is believed that the constricted end portion 40 of the shield is narrow enough to prevent needle stick injuries brought about in the main by the insertion of a persons finger into the bore 31. However, in addition to the aforementioned procedures, the user may elect to invert the cap supplied with the hypodermic needle and insert said cap into the bore 31 such that the enlarged basal portion of the cap may be used to further narrow the opening in the end portion 40. If as a consequence of a willful act, the locking member 50 is separated from the syringe 10, it will be appreciated that the locking member 50 and the hypodermic needle 14 shall be retained within the shield 30, as illustrated in figure 26. It also believed that the barbs 54 will cause sufficient damage to the external surface of the nozzle 13 that the syringe 10 could not be re-used.

Figures 27 and 28 illustrate an alternative locking member 200 to the locking member 50 illustrated in figures 8 and 9. The locking member 200, like the locking member 50, is manufactured from a plastics material. The locking member 200 includes a substantially cylindrical body portion 201 and an external annular flange 202 having an external diameter 35 which is slightly larger than both the external diameter of the barrel 11 and the distance separating diametrically opposing splines 32. it is also preferred that the height of the locking member generally indicated by arrows 203 is less than the distance separating diametrically opposing splines 32. The locking member 200 also includes a centrally located internal bore 204 defined by a continuous wall 205 having a taper which corresponds to the taper of the nozzle 13 of the syringe 10. in use, the wall 205 is adapted to frictionally engage the external surface of the nozzle 13.

The bore 204 communicates with a centrally located recess 206 which is defined by a continuous side wall 207. The recess 206 includes a downwardly and inwardly inclined upper peripheral edge 208 and two diametrically opposed ramps 209 which extend both inwardly and downwardly from said upper peripheral edge 208 and outwardly from the wall 207. The ramps 209 each include a lower guide surface 210 and a lower or trailing edge portion 211 which lies adjacent a horizontally disposed flange 212 having a lower abutment surface 213.

The recess 206 also includes two vertically orientated abutments 214 which extend downwardly from the trailing edge portion 211. The recess 206 also includes two diametrically opposed ramps 215 which extend inwardly and upwardly from the floor 220 of the recess and outwardly from the wall 207. The ramps 215 36 each include an upper guide surface 216; an upper leading portion 217 that is spaced approximately 90° from the leading portion 218 of an adjacent ramp 209, and a lower trailing portion 219 that lies almost below the leading portion 218 of the other ramp 209.

The locking member 200 also includes two diametrically opposed, externally located vertically orientated abutments 250 which extend outwardly from the side wall 201. The locking member 200 in use allows a user to releasably attach a hypodermic needle 14 directly thereto. This is achieved by firstly placing the flange 5 of the hub 17 within the recess 206 such that the end portions 6 each lie intermediate the opposing ramps 209 and rests upon the leading portion 217 of a respective ramp 215. This may also necessitate a slight urging apart of the portions of side wall 207 that lightly grip the end portions 6. Next, the hub 17 is rotated through an angle of approximately 90° such that the end portions 6 move across guide surfaces 210 and 216 until the ends 4 of the hub 17 bear against respective abutments 214; the flanges 212 overlie the end portions 6, and the surfaces 213 that bear against the end portions 6 assist in maintaining the hub 17 in operative engagement with the nozzle 13 of the syringe 10 as previously described. Rotation of the locking member 200 relative to the shield 30 and/or the syringe 10 is prevented during the process of securing the 37 hypodermic needle thereto by the abutting engagement of abutments 250 with respective ribs 43.

The hypodermic needle 14 can be easily removed from the locking member 200 by rotating the hub 17 of the needle 13 relative to the locking member 200 in the opposite direction to that when attaching the needle 14 to said locking member 200.

The hypodermic needle 14 may be attached, or separated from, the locking member 200 while shrouded by the protective cap often supplied with the needle. it will also be appreciated that use of the locking member 200 is particularly advantageous where a hypodermic needle 14 having a large external diameter is used to break the seal on a vial and to extract the contents of same. Then, if desired, the "large" hypodermic needle 14 may be replaced with a "finer" hypodermic needle 14 having a smaller external diameter for piercing a patient's skin.

Figure 29 shows another typical syringe 310 manufactured from a clear plastics material. The syringe 310 includes a cylindrically shaped, tubular body or barrel 311 having a narrow outlet associated with one end 312 thereof which fluidly communicates with an externally located nozzle 313 in the shape of a truncated cone. The external surface of the nozzle 313 is tapered and wherein the taper is commonly referred to as a Luer taper.

The nozzle 313 is surrounded by a cylindrical wall 314 which includes an internal threaded portion 38 315 .

The syringe 310 also includes a piston 316 having a head portion 317 which is sealably located within the barrel 311 and wherein the piston 316 is used to force fluids which are stored in the barrel 311 through the nozzle 313.

Figure 31 shows a hypodermic needle 320 which may be selectively attached to the nozzle 313 if so desired. The hypodermic needle 320 includes a hollow, substantially conically shaped, hub 321 surrounding a lower or basal portion 322 of a tubular needle 323 having a pointed end 324.

The hub 321 typically includes a substantially conically shaped recess 325 which is adapted to frictionally engage the nozzle 313 and an annular flange 326 which is adapted to threadably engage the internal threaded portion 315 of the cylindrical wall 314.

The syringe 310 and the hypodermic needle 320 are typically provided in separate packages and wherein the pointed end 324 of the needle 320 is usually protected by a removable sheath or cap, not shown.

Hitherto, those wishing to inject either themselves or others with a fluid were required to securely fit the hypodermic needle 314 to the nozzle 313 of the syringe 310.

Figures 35 to 38 show a substantially cylindrical shield 330 which is mountable on the barrel 311 of the syringe 310. The shield 330 is preferably manufactured 39 from a clear plastics material which is resiliently deformable, such as a high density polypropylene material .

The shield 330 incudes an internal bore 331 which is open at both ends. The bore 331 includes a main or body portion 344 having an internal diameter which is slightly larger than the external diameter of the barrel 311 of the syringe 310.

The bore 331 includes two pairs of parallel splines 332 which extend longitudinally along much of the length of the body portion 344 and wherein the pairs of splines are equally spaced from one another.

Furthermore, it is preferred that the two splines 332 which make up each pair of splines 332 are closely spaced together and that the circumferential space occupied by any one of the pairs of splines is much smaller than the circumferential distance separating the pairs of splines. As a consequence the wall portion 345 separating the pairs of splines 332 is easily deformed. it is also preferred that the distance separating diametrically opposing splines 332 is preferably slightly greater than the external diameter of the barrel 311 of the syringe 310.

The splines 332 are broken part way along their length by a discontinuity 333 and wherein the aligned discontinuities form in effect an internal annular groove 333a. Each discontinuity 333 in the splines 332 also communicates with an aligned aperture 334 formed in a side wall 335 of the shield. 40

The apertures 334 are surrounded by two external, laterally extending, annular ribs 336 and 337. Opposite each rib 336 and 337 there exists an internal, shallow, depression 338 and 339 formed in each of the splines 332.

The shield 330 also includes a cylindrical end portion 340 having an internal diameter which is smaller than the internal diameter of the opposing end portion 341 and the external diameter of the barrel 311. The end portion 340 includes four internal, evenly spaced, ribs 342 which help strengthen said end portion as well as eight adjacent ribs 343 which extend longitudinally along a small portion of they body portion 344 of the shield. The shield 330 is preferably manufactured by an injection moulding process and wherein the mould preferably includes two blocks in which there are each formed a cavity having a shape which compliments the external shape of the shield 330. The mould also includes a substantially cylindrical core located intermediate the cavities of the assembled blocks and wherein the shape of the core compliments the internal shape of the shield 330. Each of the apertures 334 and the communicating discontinuity 333 are formed by a respective projection associated with one or other of the cavities and which is configured so as to engage the core. A runner communicating with one or other of the cavities is used to supply the interior of the mould with sufficient molten plastics material to 41 construct the shield and wherein when the plastics material has set, the resulting shield 330 is stripped from the core, it is believed that the depressions 338 and 339 are formed as a consequence of the slow rate by which the plastics material comprising the ribs 336 and 337 cool when compared with adjacent thinner wall portions.

Figures 32 and 33 show a locking member 350 manufactured from a plastics material. The locking member 350 includes a body 351 having an axially located through bore 352.

The locking member 350 also includes an axially located connecting portion 353 in the shape of a truncated cone and having a continuous tapered side wall 354, (Luer taper). The connecting portion 353 is surrounded by a cylindrical wall 355 having an internal threaded portion 356.

The locking member 350 also includes an outwardly directed annular edge portion 357 having a dependent skirt 358 which is resiliently biassed toward retaining means 359 adapted to engage with the nozzle 313 of the syringe 310 and the surrounding cylindrical wall 314.

The retaining means 359 includes a downwardly directed, axially located, truncated conical portion 360 having a tapered outer continuous side wall 361 and a tapered inner continuous side wall 362, (Luer taper).

The locking member 350 also includes eight circumferentially equally spaced recesses 363 formed in an upper wall of the annular edge portion 357. The 42 recesses 363 are each adapted to receive an end portion 364 of a respective rib 343.

It is envisaged that the shield 330 and the locking member 350 will be provided to prospective users in an assembled state ready for use as a needle stick protection apparatus 370, as illustrated in figure 39, which can be selectively mounted on an existing syringe 310 prior to the attachment thereto of a hypodermic needle 320. The locking member 350 is preferably introduced to the bore 331 such that the connecting portion 353 points toward the constricted end of the shield 330. The resilience of the edge portion 357 allows the locking member to be pushed along the length of the shield using a suitable tool such that the end portion 364 of each of the ribs 343 is subsequently located in a respective recess 363 and thus provides some support for the locking member 350 when located within the shield 330. it will also be noted that a small annular band of the edge portion 357 frictionally bears against the splines 332 and thereby assist in the retention of the locking member 350 within the shield 330. in use, the needle stick protection apparatus 370 shall be mounted on the barrel 311 of a syringe 310 by inserting the barrel 311, nozzle first, into the bore 331. The nozzle 313 is preferably driven into the bore 352 of the locking member 350 such that the tapered surface (Luer taper) of the nozzle 313 frictionally engages the internal tapered wall 362 of the conical 43 section 360 which is wedged between the threaded portion 315 of the cylindrical wall 314 and the tapered surface of the nozzle 313.

An upper portion 366 of the cylindrical wall 314 also frictionally engages the skirt 358 of the edge portion 357, the skirt having been outwardly displaced by the contact with the upper portion 366 as illustrated in figure 34.

It will also be appreciated that the bore of the nozzle 313 is hence seal ably in fluid communication with the portion of the bore 352 that extends through the connecting portion 353 of the locking member.

The annular flange 326 of the hub 321 of the hypodermic needle 320 in turn may be threadably engaged with the threaded portion 356 of the locking member 350 such that the hub 321 is retained in a sealing fluid engagement with the connecting portion 353 as illustrated in figures 40 and 41.

The resulting syringe and needle assembly preferably resembles the assembly 390 illustrated in figure 40 and wherein the chamber of the syringe may be filled with a fluid to be injected into a person in the usual manner. It will be noted that the shield 330 is in it's inoperative position and wherein a significant portion of the needle 323 including the pointed end 324 is exposed.

The pointed end 324 of the needle 313 may be inserted below the person's skin and wherein the fluid contained in the chamber may be expelled from the 44 needle by movement of the piston 316 generally in the direction of the nozzle 313. Alternatively, the assembly 390 may be used to extract fluids from the person's body by moving the piston 316 generally away from the nozzle 313.

Having completed the injection or extraction of fluids, the shield 330 may be slid along the barrel 311 such that the end portion 340 of the shield bears against the person's skin. Then the pointed end 320 of the needle 319 may be removed from beneath the person's skin by pulling the barrel away from the end portion 340 with one hand while holding the shield 330 stationary in the other hand, preferably using the ribs 336 and 337 as a grip. Due to the frictional engagement of the annular edge portion 357 with the splines 332, movement of the shield 330 relative to the barrel 311 shall cause some localised deformation of the shield but wherein it is believed that some of the resistance to said movement is at least partially overcome by the flexibility of the wall portions 345. when the annular edge portion 357 is aligned with the internal depressions 338, the flange 357 shall engage the depressions 338 and wherein an audible sound signifying said engagement may be heard. Because the depressions are rather shallow the edge portion 357 and the depressions 338 may be easily disengaged thereby allowing the user to extend the pointed end 324 of the needle beyond the confines of the shield thereby 45 enabling the assembly to be used a second time to inject or extract fluids. This may be important where for example it is proposed to use the syringe to inject a person with small amounts of the fluid housed therein at different stages during a medical procedure but wherein it is desirous that the pointed end 324 of the needle is temporarily shielded by the end portion 340 when the assembly 390 is not being used.

However if the syringe 310 is not be to used again, the shield 330 may be placed in it's operative shielding position by aligning the annular edge portion 357 with the discontinuities 333 such that the edge portion 357 may be retained therein by the obstacles posed by the opposing edges 375 of the respective splines 332, as illustrated in figure 41. A second audible sound signifying engagement of the annular edge portion 357 in the discontinuities may also be heard. in addition, the sighting of the annular edge portion

357 through the apertures 334 will provide a visual means of ascertaining whether the edge portion 357 is retained in the discontinuities 333. it is believed that the constricted end portion 340 of the shield is narrow enough to prevent needle stick injuries brought about in the main by the insertion of a persons finger into the bore 331. However, in addition to the aforementioned procedures, the user may elect to invert the cap supplied with hypodermic needle and insert said cap into the bore 331 such that the enlarged basal portion of the cap may be 46 used to further narrow the opening in the end portion 340. if as a consequence of a willful act, the locking member 350 is separated from the syringe 310, it will be appreciated that the locking member 350 and the hypodermic needle 320 shall be retained within the shield 330. it will of course be realized that while the above has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is herein defined in the appended claims.

Claims

47 THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A needle stick protection apparatus including: a shield having an internal through bore which is capable of receiving the barrel of a syringe, said bore including a spline or rib in which there is formed a discontinuity which is adapted to receive a portion of a locking member associated with the syringe and which extends laterally beyond the barrel.

2. A needle stick protection apparatus including: a shield having an internal through bore which is capable of receiving the barrel of a syringe, said bore including a spline or rib which extends along part of the length of said bore and wherein there is provided a discontinuity in said spline which is adapted to receive a portion of a locking member that is associated with the syringe and which extends laterally beyond the barrel, said discontinuity being aligned with an aperture formed in a side wall of said shield.

3. A needle stick protection apparatus as claimed in claim 2, wherein said discontinuity is formed during a moulding process by a member which is retracted through said aperture.

4. A needle stick protection apparatus as claimed in claim 2 or claim 3, wherein said shield includes a plurality of circumferentially spaced splines in which there are each formed a discontinuity, said discontinuities being laterally aligned within said shield. 48

5. A needle stick protection apparatus as claimed in any one of the preceding claims, wherein said spline or said splines are each adapted to frictionally engage the locking member and wherein resistance to the sliding motion of the locking member relative to said shield is at least partly eased by the ability of selected portions of said shield to change shape.

6. A needle stick protection apparatus as claimed in claim 4, wherein at least some of said splines are separated by a resiliently deformable wall portion of said shield.

7. A needle stick protection apparatus as claimed in any one of the preceding claims, wherein said shield is manufactured from a resiliently deformable plastics material.

8. A method of manufacturing a shield of the type having an internal through bore which is capable of receiving the barrel of a syringe, said bore including a spline which extends along at least a portion of the shield and wherein the spline includes a discontinuity, the discontinuity being adapted to receive a portion of a locking member associated with the syringe, said method including: providing two blocks each having an abutment surface in which there is formed a cavity which complements the external shape of the shield to be produced and wherein the discontinuity is formed by a projection extending outwardly from one of said cavities ; providing a primary core which compliments the internal shape of the shield to be produced, said primary core having a 49 channel which complements the shape of the spline; placing the two blocks together such that the two abutting surfaces abut and wherein the cavities co-operate to form a bore and the primary core is supported within said bore and a free end portion of the projection is received within and engages the surfaces of the channel of the primary core; njecting a settable plastics material into the bore via a runner communicating with the bore; parting the two blocks, and stripping the plastics shield from the core.

9. A method of manufacturing a shield of the type having an internal through bore which is capable of receiving the barrel of a syringe, said bore including a spline which extends along at least a portion of the shield and wherein the spline includes a discontinuity, the discontinuity being adapted to receive a portion of a locking member mounted on the syringe, said method including: providing two blocks each having an abutment surface in which there is formed a cavity which complements the external shape of the shield to be produced; providing a primary core which compliments the internal shape of the shield to be produced, said primary core having a channel which complements the shape of the spline and a pin which may be selectively extended into said channel so as to form a discontinuity in the spline; placing the two blocks together such that the two abutting surfaces abut and wherein the cavities co-operate to form a bore and the primary core is supported within said bore and the pin 50 blocks off a portion of the channel; injecting a settable plastics material into the bore via a runner communicating with the bore; parting the two blocks; retracting the pin, and stripping the plastics shield from the core.

10. A needle stick protection apparatus which when assembled can be mounted on a syringe of the type which includes a tubular body or barrel having a cylindrically shaped side wall and a narrow opening formed in an end wall which fluidly communicates with an externally located nozzle to which a hypodermic needle may be selectively operatively connected, said needle stick protection apparatus including: a sleeve like shield mountable on the barrel portion of the syringe such that it can move between an inoperative position wherein the exposed pointed end of the hypodermic needle may be used to pierce a person's skin and an operative position wherein accidental contact of the pointed end of the hypodermic needle with a person's skin is obstructed by said shield, said shield being provided with an internal discontinuity located intermediate it's opposing end portions, said discontinuity being aligned with an aperture formed in a side wall of said shield; a locking member located inside said shield and which is capable of movement relative to said shield, said locking member being provided with mounting means for mounting the locking member on the syringe, said locking member having an edge portion which when located in said discontinuity assists with the retention of said shield in an operative position, said edge 51 portion being adapted to extend outwardly from the syringe in a generally lateral direction beyond the cylindrical side wall of the syringe, and retaining means located inside said shield for retaining said locking member on the syringe.

11. A needle stick protection apparatus as claimed in claim 10, wherein said discontinuity is formed during a moulding process by a member which is retracted through said aperture.

12. A needle stick protection apparatus as claimed in claim 10 or claim 11, wherein said shield includes locating means associated with one end thereof which is adapted to receive and provide support for said locking member during the process of mounting said locking member on the syringe.

13. A needle stick protection apparatus as claimed in claim 12, wherein said locating means includes a plurality of abutments against which said edge portion of said locking member may abut.

14. A needle stick protection apparatus as claimed any one of the preceding claims 10 to 13, wherein said locking member includes an aperture through which the nozzle of the syringe extends.

15. A needle stick protection apparatus as claimed in claim 14, wherein said locking member includes securing means for securing the hub of a hypodermic needle to said locking member.

52 16. A needle stick protection apparatus as claimed any one of the preceding claims 10 to 15, wherein said locking member includes retaining means which is adapted to engage an adjacent portion of the syringe.

17 A method of attaching needle stick protection apparatus of the type defined in any one of the preceding claims 10 to 16 to the nozzle of a syringe including: providing an assembled needle stick protection apparatus, and inserting the barrel of the syringe into the shield such that the locking member is located on the syringe and is retained on the syringe by engagement of the syringe with the retaining means.

18. A locking member which may be mounted on a syringe, said locking member including: an outwardly directed side portion which extends beyond the barrel of the syringe when the locking member is mounted on the syringe; mounting means for mounting the locking member on the syringe; retaining means associated with the locking member which inhibits separation of the locking member from the syringe, and securing means for securing a hub of a hypodermic needle to the locking member characterised in that the hub of the needle while secured to the locking member is able to communicate with a nozzle of the syringe. 53

19. A method of using needle stick protection apparatus of the type described in any one of the claims 1 to 7 or 10 to 17 so as to avoid needle stick injuries, the needle stick protection apparatus being mounted on a syringe which is operatively connected to a hypodermic needle, said method including: shielding the pointed end of the hypodermic needle by movement of the shield relative to the needle such that the needle is enclosed by the shield and is retained in an operative shielding position by the engagement of a portion of the locking member with the discontinuity in the shield.

20. A needle stick protection apparatus which may be used in conjunction with a syringe of the type which includes a tubular body having a narrow outlet associated with one end thereof which fluidly communicates with a nozzle to which a hypodermic needle is or may be selectively connected, a finger abutment associated with the other end of the body and a piston, said needle stick protection apparatus including: a tubular shield mountable on the body of the syringe and moveable between an inoperative position, wherein the pointed end of the needle is exposed, and an operative position, whereby the pointed end of the needle is surrounded by the free end of the shield, and finger engagement means associated with said shield, characterised in that, while the body is supported between two fingers of a user's hand that bear against the finger abutment, movement of said shield between an inoperative position and an operative position may be effected by applying pressure to said finger engagement means using the user's thumb of the same hand. 54

21. A method of using needle stick protection apparatus as claimed in claim 20 so as to avoid needle stick injuries, the needle stick protection apparatus being mounted on a syringe which includes a tubular body having a narrow outlet associated with one end thereof which fluidly communicates with a nozzle to which a hypodermic needle is or may be selectively connected, a finger abutment associated with the other end of the body and a piston, said method including: supporting the syringe between two fingers of a user's hand such that the fingers bear against the finger abutment; placing the user's thumb of the same hand against the engagement means, and moving the shield relative to the syringe such that the pointed end of the needle is surrounded by the shield, said movement being effected by pressure applied to the engagement means and the finger abutment by the thumb and fingers respectively.

22. A needle stick protection apparatus substantially as herein before described with reference to the drawings.

23. A locking member substantially as herein before described with reference to the drawings.