NZ260359A - Vaccinator for delivery of a continuously variable amount of fluid - Google Patents

Description

Patents Form # 5 260359 NEW ZEALAND Patents Act 1953 COMPLETE SPECIFICATION TITLE: Vaccinator APPLICATION#: 260359 FILING DATE: 20 April 1994 I/We,: Simcro Tech Limited Address: 23 Bandon Street, Hamilton, New Zealand Nationality: New Zealand hereby declare the invention, for which I/we pray that a patent may be granted to me/us, and the method by which it is to be performed, to be particularly described in and by the following statement: .JWP FEE CODE - 1050 FIELD OF THE INVENTION This invention relates to the field of devices for repeated delivery of preset volumes of fluid and more particularly to syringes or vaccinators adapted for repeated injection of controlled doses of fluids into humans or animals. A61M-005/20, A61M-005/315.

BACKGROUND A number of syringes or vaccinators adapted for the injection of controlled amounts of" > fluids or suspensions, which may for example be suspensions of killed bacterial cells or other proteins for vaccination, or antibiotics or anthelmintics, have been in existence for many years.

In general one of these syringes is used by a person who moves along a race filled with animals and injects each one in a preferred site with a preferred volume of fluid, often marking each of the injected animals with a marking raddle or chalk as it is done. Usually one has to hold or pluck up the skin of the animal with one hand so that the needle on the end of the vaccinator can be introduced into a subcutaneous site with the other hand. Often one has to change hands to reach awkwardly placed animals. (By "animals" we refer to mammals, birds, reptiles, fish and the like which are managed in some way by people). A supply of liquid pharmaceutical is generally a bottle or plastic bag carried by the person, through it may be suspended from a holder above or near the animals.

An ideal syringe or vaccinator is (a) reliable in terms of fluid delivery volume, (b) easy to hold and use, (c) durable, (d) easy to clean and maintain in a sterile condition (at least internally), and (e) easy to set for a particular delivered dose, although some of these conditions may be relaxed if a vaccinator can be produced cheaply enough to regard as disposable rather than reusable over long periods.

Commercial products available to date have fallen short of these requirements particularly in terms of (a) and there is accordingly a need for an improved syringe or vaccinator.

OBJECT It is an object of the present invention to provide an improved repeating syringe, vaccinating gun, or vaccinator or one which will at least provide the public with a 260359 73B3HAM.498 INTELLECTUAL PROPERTY OFFICE OF N2. 2 3 APR 1998 RECEIVED useful choice. 260359 STATEMENT OF THE INVENTION In one aspect the invention provides a syringe or vaccinator capable of being set to deliver a continuously variable amount of fluid wherein the means to control the dose is adjustment of a setting ring affecting the position of a stop within a threaded sleeve, wherein the syringe includes a handle coupled to a piston which may travel between an extended and a retracted position, and includes means to limit the extent of the retracted motion of the piston with a stop or stops, the position of which can be adjusted so that in use the piston is capable of only a limited range of travel which in combination with the barrel in place determines the delivered dose, and wherein the handle is permitted to rotate by up to 30 degrees each side of a central position and thereby adapt the configuration of the vaccinator to the shape of a left hand when the handle is twisted anticlockwise, or a right hand when twisted clockwise.

Preferably the vaccinator is made of moulded plastics parts and preferably the plastics material is polypropylene or nylon.

In a related aspect the provision of internal engaging components substantially prevents its handle from rotation and accidental alteration of the volume of fluid ejected.

In a related aspect the continuously variable dose is between one and ten millilitres (ml).

In a further related aspect the vaccinating gun may be provided with one of a range of 25 barrel sizes in order to optimise the control over the delivered dose.

Preferably these sizes are one, two, five, and ten ml barrels.

Preferably the rear assembly of the vaccinator, comprising the rear handle, compression spring, body, hose barb, adjusting ring and threaded sleeve are common to all sizes.

In a second aspect the vaccinator includes a handle coupled to a piston which may travel between an extended and a retracted position, and includes means to limit the extent of the retracted motion of the piston with a stop or stops, the position of which can be adjusted so that in use the piston is capable of only a limited range of travel 35 which in combination with the barrel in place determines the delivered dose.

"INTELLECTUAL WUVtHI i UllM-| 1' OF N.Z. 7383KAH.498 2 3 APR 1998 RECEIVED 26 0 3 59 Preferably a handle is coupled to a p:ston by internal engaging components which in use substantially prevent the handle from rotation and accidental alteration of the volume of fluid ejected.

In another aspect the invention provides a syringe or vaccinator, having a body, a barrel having an end capable of receiving a hollow needle, a handle coupled to a piston, and means for adjusting the limit of travel of the piston within the barrel, and a needle nut attached to one end of the barrel wherein the needle nut has a cutaway portion allowing 10 a hollow needle to be positioned in use in the cutaway portion without fully removing the needle nut from the barrel and movement of the needle nut relative to the barrel allows the needle to be secured to the end of the barrel.

Preferably the barrel is removably attached to the body.

In a related aspect the invention provides means for converting a rotational movement into a translational movement using moulded plastics components, the rotational movement being imparted to an rotatable adjusting ring prevented from making translational movements, which ring includes an internal thread slidably engaging with 20 a threaded member which can slide but is prevented from rotation.

Preferably the threaded member is a sleeve about the shaft of the piston, which sleeve carries one or more internal stops against which projections or splines on the shaft of the piston will engage when in its retracted position.

Preferably the projections or splinrs on the shaft of the piston engage slidably with blind grooves along the internal aspect of the threaded sleeve.

Preferably the threaded sleeve is itself prevented from rotation.

Optionally the prevention of rotation may be by means of one or more flats or keys formed on the outer surface of the sleeve which slidably engage with a conforming aperture.

Preferably there is some slop or looseness of fit between the flats or keys, and the conforming aperture, and preferably this is sufficient to provide rotation of the sleeve 7383JC1 795 26 0 3 5 9 within the aperture of the order of IS to 30 degrees either side of the centre; hence providing the rear handle of the vaccinator with an ability to twist into a left and or a right hand.

In a further aspect the invention provides a vaccinator or part thereof and any novel feature of either of them individually or collectively or any combination thereof.

DRAWINGS The following is a description of a preferred form of the invention, given by way of example only, with reference to the accompanying diagrams.

Fig 1: is an illustration in perspective view of the vaccinator.

Fig 2: is an illustration of several configurations of the vaccinator.

Fig 3: is an illustration in plan view from below of the vaccinator.

Fig 4: is an illustration of a valve seat or retainer for the vaccinator.

Fig 5: shows the piston of the vaccinator.

Fig 6: shows the worm or threaded sleeve for the vaccinator.

Fig 7: is an illustration of the hose barb of the vaccinator.

Fig 8: is another view of the valve seat or retainer.

Fig 9: shows the piston of the vaccinator in another view.

Fig 10: also shows the threaded insert for the vaccinator.

Fig 11: is a further illustration of the hose barb of the vaccinator.

Fig 12: shows details of the valve of the vaccinator. 7383JC1.795 26 0 359 Fig 13: illustrates the band, or barrel clamp ring of the vaccinator. Fig 14: shows aspects of the 5 ml barrel used in the vaccinator. Fig 15: shows the nut or needle clamp of the vaccinator.

Fig 16: illustrates the adjusting ring (for control of volume) of the vaccinator.

Fig 17: illustrates the body of the vaccinator including parts to cooperate with the threaded sleeve and the adjusting ring.

Fig 18: shows the rear grip and tube of the vaccinator with its compression spring.

PREFERRED EMBODIMENT Fig 1 shows a perspective view of the vaccinator 100. A needle nut 102 with a "cutaway" nose portion is screwed onto a barrel 103. It is described in more detail with reference to Fig 15. The "cutaway" portion allows the attachment of a needle (not shown) without fully removing the needle nut. The nut can be partly unscrewed until 20 the Luer connector 101 is flush with the base of the cutaway portion and then a Luer-lock hypodermic needle suitable for the injection procedure to be undertaken can be attached by placing its base in the cutaway portion and screwing the nut back onto the barrel so that the tapered Luer connector 101 is forced into contact with the interior of the base of the needle in order to hold the needle in place.

The barrel 103 contains a plunger moulded onto the head of a shaft 114 which taken together is called the piston; the point of contact of a resilient sealing washer 111 ([preferably made of a synthetic rubber ring) is evident inside the transparent barrel. All other parts of this vaccinator are usually made of an opaque coloured plastics 30 material, preferably polypropylene or alternatively nylon, and the instrument is assembled from injection-moulded components. The lower bulk strength of polypropylene gives a larger more "chunky" shape than if the instrument was made of (for example) nylon. Furthermore polypropylene is cheaper. Assembly of the instrument is by push fits wherein local distorting force is briefly applied to have a part 35 rise over a land and then enter a mating site or socket, as with barbs or grooves and corresponding reliefs, or by screwing together. No other fasteners are used. With 7383JC1.795 26 0 3 5 9 preferred tolerances the assembled instrument remains intact during use.

The barrel is held onto the body 105 of the instrument by a band or retaining ring 104 5 which is screwed into place. The body has projecting grips 106 and 107. Preferably these project radially and preferably one is substantially longer than the other so that the orientation of the instrument and hence the bevel of the needle can be sensed easily by a busy user. Preferably the grips have a rounded surface for contact with the user's hand.

Towards th-. rear of the body is a dose-setting ring 108 which may be rotated in order to determine the volume of fluid to be delivered from the vaccinator at each full depression of the handle 110. The handle or rear grip 110 is also preferably asymmetrical and is inclined slightly from the perpendicular in order to fit a human hand more closely.

In use, the first finger is generally placed over grip 106, the other three fingers over grip 107, and the rear grip 110 nestles naturally in the groove between the palm and the forwards-directed thumb (against the adductor pollicis muscle). As left-handed and right-handed users should be catered for equally (as often a normally right-handed 20 person will hold the gun in his/her left hand and manipulate an animal with the right hand) the rear grip can rotate about the body of the instrument by about 15 to 30 degrees in either direction (but not much more) in order to suit either hand. When the rear grip is squeezed towards the front grip, the tubular shaft 109 moves inside the body of the instrument and the piston moves towards the front of the barrel until its front is 25 reached, limiting the delivered dose. A compression spring 1804 concealed inside the shaft 109 provides a return force to press against a dose-delimiting stop. The user's thumb tends to lie along the body of the vaccinator during use.

A recess 112 under the rear grip 110 provides access for a tube carrying the fluid to be 30 injected through the connector aperture 113. Usually a fanner would carry with him a tough plastics bag containing the pharmaceutical to be used, which is sold along with a pre-inserted delivery tube. Sometimes a separate tube with a hypodermic needle on its far end is inserted immediately prior to use through a seal into a bag or bottle of pharmaceutical.

Fig 2 is an illustration of several configurations of the vaccinator, in which 200 is a 7J03JC1.7*3 ;26 0 35 9 ;-8- ;vaccinator with a 2 ml barrel 203 and piston, 201 is vaccinator with a 5 ml barrel 204, and 202 is a vaccinator with a 10 ml barrel 205 and plunger. Note that th*, 1 ml and the 2 ml barrels are externally identical. It will be appreciated that the rear sections of these 5 vaccinators 206,207, and 208 are substantially identical, thus saving in the number of parts required to provide an instrument capable of delivering a repeated series of equal doses in a continuous range of from 1 to 10 ml.

Fig 3: is an illustration in plan view from below of a 5 ml version of the vaccinator. 10 The dimensions given are from a single sample of a 5 ml vaccinator and thus are representative only. The endpiece 301 is 20 mm diameter and 25.5 mm long. The barrel 302 is 20 mm diameter at the lead line and 82 mm long - this including the distance from the Luer connector (see 101) to the wider interface to the body of the vaccinator. The retaining ring 303 is 26.5 mm long and 30 mm diameter. The visible, 15 cylindrical portion of the body 304 is 33 mm long and 30 mm diameter. The longer grip 305 (corresponding to 107) is 63 mm long; the shorter grip (not visible but like 106) is 23 mm long. The visible part of the adjusting ring at the rear is 18 mm long and it is 30 mm (max) diameter. The diameter of the tubular shaft 109 is 19.5 mm. Its visible length varies according to the dose setting chosen, since it is linked directly to 20 the piston, and the total length of the rear grip is 56 mm. The total length of the instrument, again a function of its setting, is about 192 mm. Fig 3 also shows the position of the inlet 308 for the liquid to be injected.

The liquid flows through the hose barb part shown in Figs 7 and 11, through the middle 25 of the piston shaft of Figs 5 and 9, through a one-way valve assembly (see Figs 4, 8 and 12) and into the lumen of the barrel from where it may be delivered under pressure through the needle.

Figs 4 and 8 are illustrations of a spring retainer of the vaccinator, which is inserted as 30 a friction fit into a dilated opening at the end of the piston and the barrel as seen in Fig 9. The valve comprises three components; a compression spring, a valve, and a spring retainer. Referring to Fig 12, the valve is a ball-ended plastics insert 1201,1202, 1203, 1204 and 1205 (the section 1205 being along lines A-A of 1204 .) This complex shape has been found functionally preferable to a more conventional simple ball acting as a 35 valve. The spring retainer (Figs 4 and 8) includes an external retaining rib 402, 801 and locating ribs 403. The right-hand end of 400 faces the cavity of the barrel and 7383JL. .795 26 0 3 5 9 forwards. During assembly the valve 1201 is inserted first into the piston cavity, with the spring forced and held over its stem 1206. (Dimensions given for 1205 are preferred dimensions). The spring retainer 400 is inserted last, and keeps the valve 5 against its seat (moulded into the cavity of the piston as a shaped narrowing of its lumen).

In a similar manner to that of a conventional hypodermic syringe the piston of the vaccinator is moved to and fro within the barrel during use. In the course of this it also 10 moves to and fro inside the threaded adjusting member 600, 1000 • going backwards to the limit set by the internal stop - the blind end 603 of the spline or groove 1001,1002 inside it. The adjusting member can also be moved to and fro for adjustment purposes by rotation of the dose-setting ring of Fig 16 which internally engages with the thread on the outside of the adjustment member, but if the dose-setting ring is not being turned 15 then the adjusting member can only tilt by about 15 to 30 degrees each side of centre.

Figs 5 and 9: show the piston assembly of the vaccinator; for which various sizes of piston or plunger head are provided in order to slide sealably within the corresponding barrel. 500, 900 is the piston head. It preferably incorporates one or more radial 20 grooves into a first of which 501, 901 may be inserted a resilient washer, preferably a type of "O" ring of a synthetic rubber. Optionally a felt wiping washer may be placed in a second groove. The shaft of the piston 502,902 carries the force of the operator's hand from the rear grip to the fluid to be injected, and includes an axial passage for fluid (entering at 505). The spline 503,903 and a corresponding spline on the opposite 25 side of the shaft travel along corresponding spaces inside the adjusting member shown in Figs 6 and 10, and prevent the piston from retraction, after a delivery of fluid any further than thai set by the current position of the blind ends inside the adjusting member 600, 1000 which is held by its external threads 1003 at a position determined by adjustment of the adjusting ring 108.

The valve permits refilling of the barrel, but prevents the fluid, when put under pressure, from flowing backwards along the supply pipe.

A further constraint that we have imposed on the adjusting member is prevention of its 35 own rotation. This is enforced by the rectangular slot 1703 in the body of the vaccinator, shown in Fig 17. The rectangular slot conforms to the shape of and admits 73B3JC1 795 26 0^ the opposing "flats" 1005 and 1006 of the adjusting member and allows it to slide through the slot, but not to rotate. The "flats" are not actually single flat surfaces but resemble flattened "V" shapes in cross section. This improvement provides the rear 5 grip of the vaccinator with the freedom to rotate about 15 to 30 degrees in either direction in relation to the body, but not much more (under normal amounts of force).

Figs 6 and 10 show the threaded sleeve for the vaccinator. This is used with the blind end 603 of the internal grooves or splines 1001,1002 towards the rear of the vaccinator. 10 The internal splines engage with the piston shaft, which is engaged with the rear grip, and so limit rotation of the rear grip with relation to the body. The label 603 indicates the blind end of one of two paraxial grooves which extend throughout most of the length of the threaded sleeve. The splines or projections 503 of the piston will slide within these grooves.

Figs 7 and 11 show the hose barb of the vaccinator.

As shown in Figs 3 and particularly in Fig 1 at 113, the connector to the flexible plastics pipe from a source of pharmaceutical is brought out at a protected place beneath the rear grip, where a connected pipe is unlikely to be dislodged by accidental 20 contact thus allowing the pharmaceutical (which may be hazardous to operators through having antigenic or allergenic materials, or living organisms within it) to be released.

An amply barbed (three circumferential barbs ate shown) connection spigot 704 with an orifice 705 at its tip projects radially from the axis of the vaccinator, and may be fitted 25 into a plastic tube from a supply of fluid. The central cavity of the hose barb emerges into the at 701, whe>w this part is mated in a substantially watertight manner optionally with O-ring sealing using an O-ring in the groove 507 close to the end 505 of the piston assembly, and this part also transmits the hand pressure applied to the vaccinator onwards to the piston and so to the fluid. The side wings 706 fit into recesses moulded 30 within the base of the rear handle. Interlocking of the fluid connector and the shaft is provided for by barbs 504 and corresponding sockets 702. At the time of installation, this hose barb, pushed into place on a piston, is inserted towards the rear of the rear grip inside the tube. The hose barb and piston are distorted (bent) as the barb approaches the aperture 112 and pops out into the aperture when in place. The barb held in its aperture 35 largely comprises the coupling between the piston and the rear grip. 7383JC1.795 26 0 3 5 & Fig 13: illustrates the barrel clamp ring 1300 of the vaccinator. This part is made in three sizes. Although there are four barrel sizes (one, two, five and ten millilitres) the one and two millilitre sizes are externally identical. Internally the barrel clamp ring is 5 provided with a spiral relief forming a thread 1301, but as the width of the spiral relief is only about 20% of the pitch of the thread (as shown in the section 1302) it is possible to provide without conflict a semicircular raised lip 1608 on the end of the 10 ml barrel, extending for 180 degrees around the preferably 25 mm diameter circumference, which provides a locking formation for the barrel. The semicircular lip engages with the 10 locking ring while the remainder of the barrel, which has a lesser diameter of typically 22.5 mm, dives beneath the body 105. (In the case of the smaller barrels the entire barrel increases in diameter in a truncated cone or taper and so can be securely locked in place because the locking ring for these is designed to engage with the tapering portion. (If the 10 ml barrel was also given a taper section then the diameter of the 15 entire vaccinator would be unduly large).

Fig 14 shows aspects of the 5 m! barrel used in the vaccinator. The body of the preferably transparent barrel 1404 tapers out at 1403 to a wider body connection 1401: this section fits within the body part 105 of the vaccinator. An orientating groove is 20 provided at 1402, which mates with a raised line inside the body. This maintains the calibration marks at a preferred site around the vaccinator. At the delivery end, 1406 is a Luer taper to fit inside the hub of a Luer type hypodermic needle. The barrel carries a screw thread at 1407 (the thread is not shown in detail in the drawing), onto which the nut or needle clamping ring is screwed. Other diameters of barrel include similar 25 mating components so that the same rear end can be used with a variety of barrels.

Fig 15: shows the nut or needle clamp ring of the vaccinator. The internal thread is shown at 1503: the needle retaining lip is at 1502, and the body of the ring is at 1501. The semicircular cutaway is provided so that needles can be replaced without entirely 30 unscrewing the needle clamp ring.

The "cutaway" portion allows the attachment of a needle (not shown) without fully removing the needle nut from the barrel. In use the nut can be partly unscrewed until the Luer connector 1406 of Fig 14 is flush with the base of the cutaway portion and 35 then a Luer-lock hypodermic needle (not shown) can be attached by placing its base in the cutaway portion and screwing the nut back onto the barrel so that the tapered Luer 7383JC1.795 26 0 3 5 connector 1406 is forced into contact with the interior of the base of the needle in order to hold the needle in place.

The internal thread (not drawn) 1503 fits onto the thread of the barrel. The drawing shows a "cutaway" portion of 180' but we have found that by reducing the "cutaway" portion to slightly less than 180' we can still allow the needle to be inserted from the side but at the same time provide greater support for the base of the needle as it is 10 clamped onto the delivery end by rotation of the needle nut.

Fig 16: illustrates the adjusting ring of the vaccinator. This part has the function of setting the dose to be administered, or, of limiting the retraction of the piston so that 15 only a certain (preset) dose can be administered. 1601 is an external knurled ring attached to a wide-bore tubular section 1602. The other end of this tube is provided with a small radial groove (preferably continuous). This is press-fitted into a corresponding rib 1704 within the body. This fixing means has the result of allowing the adjusting ring 1601 to turn but not to move along the axis of the vaccinator. At the 20 time of installation (preferably) the adjusting device or threaded sleeve of Figs 6 and 10 is threaded into the thread 1604 of the adjusting ring. After assembly the threaded sleeve is held in place along the axis of the instrument by this thread and by the mating groove 1603 and its radial ridge 1704. The threaded sleeve itself cannot rotate substantially within this threaded aperture because it is held on the outside by a 25 rectangular slot in the bcdy of the vaccinator, at 1703.

Fig 17: illustrates the body 1700 of the vaccinator including means to cooperate with the threaded sleeve and the adjusting ring. The threaded sleeve passes through the body within a rectangular aperture 1703, which restricts the rotation of the threaded sleeve to 30 only a predetermined amount of play, which is about 15 to 30 degrees each side of centre and which is intended to allow the instrument to be used comfortably in either the left or the right hand. At the same time the body provides within its inner aspect a circumferential ridge 1704 which holds the adjusting ring in place and limits it lo only rotational movement relative to the body. Holding the body and turning the adjusting 35 ring causes the threaded sleeve to move either into or out of the body, which, in an assembled instrument, causes the resting, rearmost position of the piston to move 7383JC1.795 £6 0 35 9 forwards or backwards.

An advantage of this adjustment method is that rotation of the rear grip or handle cannot affect the dose delivered because the handle cannot rotate, and another advantage is that the spring is not compressed any more by adjustment than it is by use over the same range. In other words, adjustment itself does not provide a differently compressed spring.

The rear grip comprises a wide tube portion 1800 with a hand grip 1801 at one end and an aperture for the hose barb at 1802. It is designed to accommodate the piston shaft and a compression spring within it, and it internally holds ths hose barb of Fig 11 by its side wings 706. The preferred compression spring 1804 is 95 mm long, 15 mm diameter, (with one end larger and the other smaller) and is made of 1.3 mm steel wire.

As the compression spring is concealed the instrument is less easily dirtied or damaged, and the wide diameter tube attached to the rear grip is inherently stiff.

Many variations may be made to this construction of a vaccinator gun. For example, different plastics may be used. The castellated appearance of the inner border represents an option to cause the knurled adjusting knob to move in defined steps or be held in an exaggerated kind of friction lock. Other valve arrangements, or other piston seals may be used. A hose clamp may be provided to provide for tying the hose to the rear grip in some way to improve the security of its attachment.

Finally, it will be appreciated that various alterations and modifications may be made to the foregoing without departing from the scope of this invention as set forth. 7383JC1.795 26035

Claims (14)

WHAT WE CLAIM IS:

1. A syringe or vaccinator capable of being set to deliver a continuously variable amount of fluid wherein the means to control the dose is adjustment of a setting ring affecting the position of a stop within a threaded sleeve, wherein the syringe includes a handle coupled to a piston slidable in a barrel which may travel between an extended and a retracted position, and includes means to limit the extent of the retracted motion ^ of the piston with a stop or stops, the position of which can be adjusted so that in use the piston is capable of only a limited range of travel which in combination with the barrel in place determir.es the delivered dose, and wherein the handle is permitted to rotate by up to 30 degrees each side of a central position and thereby adapt the 15 configuration of the vaccinator to the shape of a left hand when the handle is twisted anticlockwise, or a right hand when twisted clockwise.

2. A syringe or vaccinator as claimed in claim 1, wherein the syringe is made of 2Q moulded plastics.

3. A syringe or vaccinator as claimed in claim 1 or 2, wherein the setting ring is a rotatable adjusting ring which is prevented from making translational movements, which ring includes an internal thread slidably engaging with the threaded sleeve which 25 can slide but is prevented from rotation.

4. A syringe or vaccinator as claimed in claim 3, wherein the threaded sleeve is around the shaft oi the piston, which sleeve carries internally one or more of said stops 30 against which projections or splines on the shaft of the piston will engage when in its retracted position.

5. A syringe or vaccinator as claimed in claim 4, wherein the projections or splines 35 on > • shaft of the piston engage slidably with blind grooves along the internal aspect of the threaded sleeve. 7 393HAM.690 INTELLECTUAL PR';?ERTV office OF N.2. 1 8 JUN 1998 RECEIVED - 15- 260359

6. A syringe or vaccinator as claimed in claim 5, wherein there is means to prevent substantial rotation of the threaded sleeve. 5

7. A syringe or vaccinator as claimed in claim 6, wherein the means to prevent substantial rotation comprises one or more flats or keys formed on the outer surface of the sleeve which slidably engage with a conforming aperture.

^ 8. A syringe or vaccinator as claimed in claim 7, wherein there is some slop or looseness of fit between the flats or keys, and the conforming aperture to allow limited rotation of the sleeve within the aperture of the order oi" 15 to 30 degrees either side of the centre; so that in use the handle of the syringe can be twisted into a left hand or a 15 right hand position.

9. A multi-dose syringe or vaccinator as claimed in claim 1, wherein the handle is coupled to the piston by internal engaging components which in use substantially 7q prevent the handle from rotation and accidental alteration of the volume of fluid ejected.

10. A syringe or vaccinator, as claimed in claim 1, the barrel having an end capable of receiving a hollow needle, and a needle nut attached to one end of the barrel wherein 25 the needle nut has a cutaway portion allowing a hollow needle to be positioned in use in the cutaway portion without fully removing the needle nut from the barrel and movement of the needle nut relative to the barrel allows the needle to be secured to the end of the barrel. 30

11. A syringe or vaccinator as claimed in claim 10, wherein the barrel is removably attached to the body. 35

12. A syringe or vaccinator as claimed in claim 11, wherein the syringe is provided with one of a range of barrel sizes in order to optimise the cK®IIc3e5w5l 73B3HAK.699 OF N.Z. 1 8 JUN 1998 RECEIVED 5 10 -16- 260359 dose.

13. A syringe or vaccinator as claimed in claim 12, wherein these sizes are one, two, five, and ten ml barrels.

14. A syringe or vaccinator as claimed in claim 1, substantially as hereinbefore described with reference to any one of the accompanying drawings. JAMES W PIPER & CO. Attorneys tor the Applicant Simcro Tech Limited 15 1^76^ 35 73B3KAM.698 INitutcrUAL^PHurEflTY OFFICE J 8 JUN 1998 | - RECEIvrn