AU2012101441A4 - Syringe Safety Prefillable - Google Patents

Syringe Safety Prefillable Download PDF

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Publication number
AU2012101441A4
AU2012101441A4 AU2012101441A AU2012101441A AU2012101441A4 AU 2012101441 A4 AU2012101441 A4 AU 2012101441A4 AU 2012101441 A AU2012101441 A AU 2012101441A AU 2012101441 A AU2012101441 A AU 2012101441A AU 2012101441 A4 AU2012101441 A4 AU 2012101441A4
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AU
Australia
Prior art keywords
plunger
syringe
barrel
needle
extension
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AU2012101441A
Inventor
Jose O. Cota
Lucio O. Cotta
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Cota Jose
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Cota Jose
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Priority to AU2012101441A priority Critical patent/AU2012101441A4/en
Application granted granted Critical
Publication of AU2012101441A4 publication Critical patent/AU2012101441A4/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Abstract

Abstract prepared by Examiner A syringe comprising: a barrel (24) for holding a fluid for injection; a needle holder (14) within the barrel (24) and located adjacent a first end of the barrel (24), said needle holder (14) being configured to hold a needle (16) extending from a first end thereof and including a first locking arrangement (54) accessible from a second end thereof; a plunger (18) located within the barrel (24) such that it forms a seal with an inside surface of the barrel (24) to enable the plunger (18) to force fluid from the barrel (24) via a needle (16) as the plunger (18) is pushed towards the first end of the barrel (24) in use, the plunger (18) including a first locking arrangement (54) that is configured to cooperate with the first locking arrangement (54) of the needle holder (14) to lock the plunger (18) to the needle holder (14); the plunger (18) further including a second locking arrangement (60) accessible via a second end thereof; a plunger extension (20), received within the barrel (24), said plunger extension (20) being configured to enable the plunger (18) to be pushed towards the first end of the barrel (24) by applying a pushing force to the plunger extension (20); the plunger extension (20) including a locking arrangement that is configured to cooperate with the second locking arrangement (60) of the plunger (18) to lock the plunger extension (20) to the plunger (18). "46 ) 4

Description

2012101441 21 Sep 2012 ι
AUSTRALIA
Patents Act 1990
PROVISIONAL SPECIFICATION FOR THE INVENTION ENTITLED: Syringe, safety prefillable
Applicant:
Jose O Cota and Lucio Oolvic Cotta
The invention is described in the following statement: 10350174 2012101441 21 Sep 2012 2
Syringe
Field of the invention
The present invention generally relates to a syringe with safety features.
Background of the invention 5 The administration of therapeutic drugs via injection is an indispensable delivery method for numerous drugs critical to patient health and well-being. Prefilled syringes are gaining popularity due to their many perceived advantages including greater medication safety and increased convenience compared to a conventional syringe.
The availability of an increasing number of drugs in pre-filled insertable and disposable 10 cartridges are also propelling the growth of prefilled syringes. Moreover, the cost of expensive biologicals, such as recombinant proteins, has created interest in prefilled syringes to reduce cost and waste associated with the handling of vial-packaged drugs.
Needle stick injuries are among the most common injuries to healthcare professionals all over the world and therefore injection safety is a high priority when prefilled syringes are 15 developed. Healthcare workers may experience a needlestick injury while administering a vaccine or a curative injection, recapping a needle, disassembling a syringe or during a process of handling and disposing of medical waste. The World Health Organisation (WHO) reported, in its 2002 World Health Report, that of the 35 million health workers in the world, two million experience a percutaneous exposure to infectious diseases every year. WHO regional reports 20 suggest that, on average, a health worker receives four needle stick injuries per year. The scale of the problem has prompted some governments to respond with policies to protect healthcare workers from this occupational hazard.
Hence, preventing accidental injury and infection from used hypodermic needles has attracted considerable interest in recent years and has created a need for technological advances 25 in medical equipment.
In order to minimize the risk of needle stick injuries, retractable syringes have been developed which enable retraction of the needle into the barrel of the syringe following use and 10350174 2012101441 21 Sep 2012 3 prior to disposal. Retraction and retention of the possibly contaminated needle into the barrel protectively isolates the needle and keeps it out of further human contact. US patent number 7988675, titled, “Automatic injection and retraction devices for use with pre-filled syringe cartridges”, describes an automatic injection and retraction device. The 5 retraction and injection assemblies are configured so that, upon application of a twisting torque to the injection and retraction assemblies, the activation-prevention feature moves from an on position to the off position simultaneous with applying the removal force to the needle guard.
These syringes described above have workable mechanisms to retract the needle so that any untoward exposure to the contaminated needle and or the syringes could be successfully 10 avoided. However, most of these syringes which retract the needle into the barrel of the syringe have inconvenient, complicated locking or disengagement steps and multiple components including spring mechanisms to release the needle from its injecting position so as to allow it to be withdrawn into the barrel. Because of the complexities of the retracting mechanism and the technology involved the retractable syringes tend to become complicated and costly as compared 15 to conventional syringes
Accordingly there is a need to simplify such mechanisms in order to reduce cost, or at least to provide a useful alternative to existing syringes.
Reference to any prior art in the specification is not, and should not be taken as, an acknowledgment or any form of suggestion that this prior art forms part of the common general 20 knowledge in Australia or any other jurisdiction or that this prior art could reasonably be expected to be ascertained, understood and regarded as relevant by a person skilled in the art.
Summary of the invention
In broad concept the present invention provides a syringe in which a plunger of the syringe is not coupled to its actuating mechanism during the ordinary process of ejecting fluid 25 from the syringe. Advantageously because the plunger of the syringe is not coupled to its actuating mechanism during the ordinary process of ejecting fluid from the syringe cannot be used to draw fluid.
After the end of the stroke, the plunger may be locked at the end of its stoke to disable the syringe. 10350174 2012101441 21 Sep 2012 4
Preferably the plunger is locked to a component carrying the needle. The plunger can also be engaged with the actuator and this engagement can be customised to make the prefilled syringe, company and/or product specific, to allow the retraction of the needle into the syringe rendering it safe for further handling. 5 The option of facilitating the needle retraction by using a compression spring which is activated by the engagement of the plunger tip to the needle holder can provide an alternate fail safe mechanism. Further disabling can be provided by facilitating the breaking of the actuating mechanism to prevent accidental reversal of the needle retraction process.
In a first aspect, the present invention provides a syringe. The syringe comprises, a barrel 10 for holding a fluid for injection; a needle holder within the barrel and located adjacent a first end of the barrel, said needle holder being configured to hold a needle extending from a first end thereof and including a first locking arrangement accessible from a second end thereof; a plunger located within the barrel such that it forms a seal with an inside surface of the barrel to enable the plunger to force fluid from the barrel via a needle as the plunger is pushed towards the first end 15 of the barrel in use, the plunger including a first locking arrangement that is configured to cooperate with the first locking arrangement of the needle holder to lock the plunger to the needle holder; the plunger further including a second locking arrangement accessible via a second end thereof; and a plunger extension, received within the barrel, said plunger extension being configured to enable the plunger to be pushed towards the first end of the barrel by 20 applying a pushing force to the plunger extension; the plunger extension including locking arrangements, preferably using a lock and key design which is company and/or product specific that is configured to cooperate with the second locking arrangement of the plunger to lock the plunger extension to the plunger.
Preferably, in use the plunger is locked to the needle holder before the plunger extension 25 is locked to the plunger, to render the plunger inoperable to dispense or draw fluid with the syringe. By locking the plunger to the needle holder first, the plunger cannot be drawn back by the as yet unattached plunger extension, thus preventing the plunger from being used to draw fluids into the barrel. Then, when the plunger extension is locked to the plunger the needle holder may be withdrawn into the barrel to thereby withdraw a needle held thereon to be 30 withdrawn into the barrel. 10350174 2012101441 21 Sep 2012 5
The locking arrangements between the plunger and needle holder, and/or the plunger extension and plunger can include a pin located on one of the parts that is received into a correspondingly shaped recess in the mating part. The pin can have one or more barbs, or flanges formed on it that engages with a corresponding groove or rib on the other part. Other 5 mechanical engagements may also be used. Preferably the locking arrangements engage with the application of a pushing force to the end of the plunger extension.
Preferably, the first locking arrangement of the plunger is configured to lock with the first locking arrangement of the needle holder by a first action; and the locking arrangement of the plunger extension is configured to lock with the second locking arrangement of the plunger by a 10 second action, wherein the second action cannot occur before the first action. The actions can both be a pushing action or application of a force. For example, the first action is the application of a first force to the plunger in a direction towards the first end of the barrel; and the second action is the application of a second force to the plunger extension in a direction towards the first end of the barrel. 15 Preferably, the first force is less than the second force and both the first force and second force are applied by a pushing force on the plunger extension. In this way, the natural pressing action of the user of the syringe will engage the locking arrangements.
As noted above it is preferable that a force required to dispense fluid from the needle in use is insufficient to cause locking of the plunger extension to the plunger. In this case, because 20 the plunger extension will not lock to the plunger until after the plunger is fully depressed the plunger extension can be pulled away from the plunger without retracting the plunger. This enables the user to cease dispensing fluid immediately, but prevents the user from using the syringe to draw fluid into the barrel.
The plunger extension preferably includes a frangible portion to enable the plunger 25 extension to be disabled after the withdrawal of the needle into the barrel. For example, the plunger extension can be provided with a line or weakness or other user-breakable feature that enable the plunger extension to be snapped off once the syringe has been used. The frangible portion is preferably placed along the plunger extension at such a distance that the plunger extension needs to be drawn up the barrel sufficiently far that the needle is fully retracted into the 30 barrel before the frangible portion is free of the barrel. 10350174 2012101441 21 Sep 2012 6
The syringe can include a capture mechanism arranged to capture at least the locking arrangement of the plunger within the barrel. Most preferably this is integrally formed with the barrel. Advantageously, this can prevent access to the plunger and needle and thereby prevents disassembly of the syringe, which may enable disengagement of the locking arrangements. 5 The capture mechanism can form part of a plunger extension guide arranged in use to guide the plunger extension within the barrel.
The needle holder can includes a fitting thereon arranged to receive a hypodermic needle mounted to a needle connection. For example, the needle holder can include a luer taper fitting to enable needles to be mounted using luer-lock or luer-slip fittings. Other fittings can also be used. 10 Alternatively, the needle holder can have a hypodermic needle mounted directly therein.
The syringe can include a seal to prevent leakage of fluid from the syringe prior to use. The seal can be in the form of a cap or plug or the like.
The syringe can include a cap mounted adjacent the first end of the barrel to protect a needle mounted to the needle holder. 15 Most preferably, the syringe is prefilled with a fluid to be injected.
Preferably, the barrel of the syringe is dimensioned to allow the plunger to be pushed a predetermined stroke distance along its length to enable dispensing of a predetermined dose of fluid. The locking of the needle holder to the plunger preferably occurs at the end of said stroke. Preferably when continued pressure is applied to the plunger extension, the second locking 20 arrangement is engaged and the plunger extension and plunger become locked.
As used herein, except where the context requires otherwise, the term "comprise" and variations of the term, such as "comprising", "comprises" and "comprised", are not intended to exclude further additives, components, integers or steps.
Further aspects of the present invention and further embodiments of the aspects described 25 in the preceding paragraphs will become apparent from the following description, given by way of example and with reference to the accompanying drawings. 10350174 2012101441 21 Sep 2012 7
Brief description of the drawings
Preferred forms of the present invention will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:
Figure 1 is a perspective exploded view of a syringe according to an embodiment of the 5 present invention;
Figures 2A and 2B illustrate a cross sectional and perspective views respectively of a barrel component of the syringe of figure 1;
Figures 3A and 3B illustrate a cross sectional and perspective views respectively of a plunger extension of the syringe of figure 1; 10 Figures 4A and 4B illustrate a cross sectional and perspective views respectively of a plunger of the syringe of figure 1;
Figures 5A and 5B illustrate a cross sectional and perspective views respectively of a needle holder of the syringe of figure 1;
Figure 6 illustrates a cross sectional view of a cap that can be used on the syringe of 15 figure 1;
Figure 7 is a perspective cut-away view illustrating a prefilled syringe according to an embodiment of the present invention prior to use;
Figure 8 is a perspective cut-away view illustrating the syringe of figure 7 when an initial force is applied to the plunger extension to dispense fluid from the needle; 20 Figure 9 is a perspective cut-away view illustrating the syringe of figure 7 when the force on the plunger extension is reversed and it is pulled away from the needle, as if to draw fluid into the syringe;
Figure 10 is a perspective cut-away view illustrating the syringe of figure 7 at the end of its dispensing stroke, with the plunger engaged with the needle holder; 25 Figure 11 is a perspective cut-away view illustrating the syringe of figure 7 after further pressure is applied to the plunger extension and it has become locked with the plunger; and 10350174 2012101441 21 Sep 2012 8
Figure 12 is a perspective cut-away view illustrating the syringe of figure 7 after the plunger extension has been pulled back and the plunger, needle holder and needle have been retracted into the barrel.
Detailed description of the embodiments 5 Figure 1 illustrates a preferred embodiment of a syringe of the present invention in a perspective exploded-view. As can be seen the syringe 10 includes four main components as follows: A body, 12; A needle holder 14 with a needle 16; 10 A plunger 18; A plunger extension 20.
When assembled the needle holder 14 is received into a first end 22 of the barrel 24 of the body 12, such that the needle 16 extends from the first end of the barrel in a manner similar to a conventional syringe. However, unlike conventional syringes the needle holder 14 is slideable 15 within the barrel 24 to enable the needle 16 to be retracted into the barrel 24 after use. The needle holder 14 is fitted in the barrel 24 such that is seals with the insider surface of the barrel. To aid sealing it can be provided with an o-ring or other seal (not shown). Next the plunger 18 is inserted into the barrel 24 of the body 12. The barrel 24 may first be filled with fluid to be dispensed if the syringe 10 is to be pre-filled (or it may be filled later via the needle). Behind the 20 plunger 18, there is provided a plunger extension 20. In use, the plunger extension is pressed by a user and it in turn pushes the plunger 18 along the barrel to push fluid from the needle 16. As can the plunger extension 20 includes a pad 26 to which pressure can be conveniently applied by a user to push the plunger 18.
The body 12 also includes a mechanism 28 for capturing at least part of the plunger 25 extension 20 and plunger 18 within the barrel. In this case, the mechanism 28 both closes off the barrel 24 and provides a cross-shaped guide 30 in which keeps the plunger extension 20 aligned along the centre line of the barrel. The mechanism 28 is formed in this case by a pair of flaps 32 and 34 that extend from the finger grip tabs 36 and 38 of the body 10. The tabs 32 and 34 each 10350174 2012101441 21 Sep 2012 9 have half of the cross -shaped guide 30 formed in them. During manufacture the body is formed from a single piece of suitable plastics material and after assembly of the other components the flaps 32 and 34 are folded to capture the plunger extension 20. They 32, 34 are held in place by bonding them to the finger grip tabs 36 and 38, e.g. by gluing or welding. 5 Details of each of the components will now be provided.
Figures 2A and 2B illustrate a cross sectional and perspective views respectively of a barrel component of the syringe of figure 1. The body 12 has a generally cylindrical barrel 24 which is used to hold a liquid to be dispensed. At a first end 22 of the barrel 24 the body has a means to retain the needle holder 14 within the barrel. The means for holding the needle holder 10 could be or more ribs or a stepped bode profile as in this example. The stepped profile at the end 22 prevents the needle holder 14 from being pushed out of the front of the body, but allows the needle holder 24 to be retracted into the barrel 24 after injection. The first end 22 of the barrel 24 has an opening 40 through which the needle 16 (and possibly part of the needle holder 14) extend. The size of the opening 40 is sufficiently large that any protruding component of the 15 needle 16 or needle holder 14 can be retracted back into the barrel 24 through the opening.
The other end of the body has a finger grip formed form a set of tabs 36 and 38. The end of the barrel 24 is closed off after assembly of the components of the syringe into the barrel 24 by a capturing mechanism 28. The capture mechanism is formed by a pair of tabs 32 and 34 that are bonded to the tabs 36 and 38. The capture mechanism 28 includes a cross shaped guide hole 20 30 through it, which guides the stem 42 of the plunger extension 20 in use.
Figures 3A and 3B illustrate a cross sectional and perspective views respectively of a plunger extension 20 of the syringe of figure 1. The plunger extension 20 operates as an actuator and is used during operation of the syringe to apply a force to the plunger 18. The plunger extension 20 comprises an elongate stem 42. On a front end of the stem there is located a locking 25 mechanism 44, that is arranged to cooperate with a locking mechanism of the plunger 18 to enable them to be locked together. The locking mechanism 46 comprises a pin 46 that terminates in a head 48. the head 48 is wider than the pin and when engaged into a receiving recess of the locking mechanism of the plunger 18 forms a positive lock with it. The head 48 and pin 46 have a groove 50 formed in them to allow them to be compressed so that they can be received into the 30 constricted opening to the receiving recess of the locking mechanism of the plunger 18. Part 10350174 2012101441 21 Sep 2012 10 way along the stem 42 there is a waist 52. This waist 52 forms a frangible section in the plunger extension 20 that is renders the stem 42 breakable by a user after retraction of the needle into the barrel 24.
On the rear end of the stem 42 there is pad 26 which can be pushed or pulled by a user to 5 actuate the syringe.
Figures 4A and 4B illustrate a cross sectional and perspective views respectively of a plunger of the syringe of figure 1. The plunger 18 has three main features: a first locking mechanism 54 at a front end 56 of the plunger 18 for engaging with the needle holder 14; 10 a sealing region 58 around a periphery of the plunger, for forming a sealing engagement with an inside surface of the barrel 24 so that fluid can be pushed through the syringe; a second locking mechanism 60 at a rear end 62 of the plunger 18 for engaging with the locking mechanism 44 of the plunger extension 20.
In this example,the first locking mechanism 54 is generally the same as the locking 15 mechanism 44 of the plunger extension, although it may be different in other embodiments of the present invention. The first locking mechanism 54 comprises a pin 58 that terminates in a generally frustoconical head 60. In the plunger the groove 62 performs the additional function of allowing all fluid behind the head to pass by the head and be injected through the needle 16.
The seal 58 comprises a rib 68 that is sized to seal with the inside of the barrel 24 to push 20 fluid through the syringe 10. The seal may additionally include one or more an o-rings or other separate sealing members. The plunger 18 also includes a cylindrical guide surface 66 to maintain the plane of the seal 64 perpendicular to axis the barrel 24 to maintain the seal.
The second locking mechanism 66, at the rear of the plunger 18 includes a recess 68 for receiving the locking mechanism 44 of the plunger extension 20. The recess 68 has a first 25 constricted entry way in the form of the narrow bore section 70. This entry that leads into a generally frustoconically tapered bore 72. The base of the tapered bore is larger that the entryway. 10350174 2012101441 21 Sep 2012 11
In use, when the head 48 of the plunger extension 20 is inserted into the bore 68. The head is compressed through the entry way and expands into the tapered bore 72. Once inserted the head 48 of the plunger extension 20 returns to its ordinary dimension and locking into place in the recess 68. The head 48 of the plunger extension 20 is held against removal by the shoulder 5 74 formed between the base of the tapered bore 72 and the narrow entry way 70.
Figures 5A and 5B illustrate a cross sectional and perspective views respectively of a needle holder of the syringe of figure 1. The construction of the needled holder 14 is somewhat similar to the plunger 18 in that is has a locking mechanism 80 accessible via its rear end 82 and a peripheral sealing surface 84. The fit of the needle mount 14 within the barrel 24 should be 10 sufficiently snug that the needle mount 14 is not moved by the insertion of the needle 16 into the patient. This can be achieved by using one or more ribs or other formations on the engaging surfaces of one or both of the needle mount 14 and the barrel 24. However, the locking force provided by this mechanism must be able to be overcome to allow the needle mount 14 to be retracted using the plunger extension in the manner described below. 15 The locking mechanism 80 is of generally the same construction as the second locking mechanism 66 of the plunger 18. In this regard the locking mechanism 80, includes a recess 86 for receiving the locking mechanism 54 of the plunger 18. The recess 86 has a first constricted entry way in the form of the narrow bore section 88. This entry that leads into a generally frustoconically tapered bore 90. The base of the tapered bore is larger that the entryway 88. 20 Importantly, the locking mechanism that locks the plunger 18 to the needle mount 14 differs from the locking mechanism that locks the plunger extension 20 to the plunger 18, namely the force required to engage the locks is different. More specifically the force required to lock the plunger 18 to the needle mount 14 is less than the force required to lock the plunger extension 20 to the plunger 18. This can be achieved by having slightly different relative sizes 25 for the locking mechanism components or by using components with different mechanical properties, e.g. different deformation properties etc. The difference in locking force means that in ordinary use the user should not lock the plunger extension 20 to plunger 18 before the plunger 18 is locked to the needle mount 14.
The recess 86 needle mount 14 has a through hole in it 92 through which fluid id 30 dispensed. In this case the through hole 92, directly receives a needle 16 and forms a seal 10350174 2012101441 21 Sep 2012 12 therewith. Alternatively the tip region 94 of the needle mount 14 can be provided with a needle connection fitting e.g. a luer taper (with a luer lock or luer slip fitting) to receive a needle.
Figure 6 illustrates a cross sectional view of a cap that can be used on the syringe of figure 1. The cap 100 is generally a conventional syringe cap 100, and can be arranged to form 5 either a friction or sealing fit with the body 12 of the syringe or tip region 94 of the needle holder 14. In this way the cap can either seal the fluid to be dispensed in a pre-filled syringe or simply be used to protect the needle from soiling or damage prior to use.
Figures 7 to 12 will now be used to describe how a syringe of the type illustrated herein may be used. Figure 7 is a perspective cut-away view illustrating a prefilled syringe according to 10 an embodiment of the present invention prior to use. As can be seen the syringe 10 is assembled with the plunder 18 retracted and disengaged from the plunger extension 20 and needle holder 14. The volume with the barrel 24 between the plunger seal 64 and the needle mount 14 is prefilled with a specified dose of a fluid 102 to be injected. The syringe is also sealed with cap 100. The barrel can be marked, in a conventional fashion, with graduations and other 15 measurement indicia to enable a smaller dose to also be accurately administered. To use the syringe the cap 100 is removed and the plunger extension 20 is pushed. Figure 8 is a perspective cut-away view illustrating the syringe of figure 7 when an initial force is applied to the plunger extension 20 to dispense fluid from the needle. In this state the plunger extension 20 is pushed forward and pushes on the plunger to move it forward and dispense fluid. Although the locking 20 mechanism 44 of the plunger extension 20 touches the corresponding locking mechanism 66 of the plunger 18, the force required to push the plunger 18 along the barrel 24 is insufficient to engage the lock between the plunger 18 and plunger extension 20. If an attempt is made to draw fluid into the syringe 10 by pulling the plunger 18 backward using the plunger extension 20 the plunger extension 20 will simply pull away from the plunger 18 without withdrawing it. Figure 25 9 is a perspective cut-away view illustrating the syringe of figure 7 when the force on the plunger extension is reversed and it is pulled away from the needle, as if to draw fluid into the syringe. This mechanism renders the syringe a “one way” device that cannot be re-filled via the needle or re-used.
Figure 10 is a perspective cut-away view illustrating the syringe of figure 7 at the end of 30 its dispensing stroke. In this state the whole dose has been dispensed and the plunger 18 is locked to the needle holder 14. Because the force required to lock the plunger 18 to the needle 10350174 2012101441 21 Sep 2012 13 mount 14 is less than the force required to lock the plunger extension 20 to the plunger 18 initially, at the end of the dispensing stroke, application of a first force engages only the first locking mechanism 54/80 between the plunger 18 the needle holder 14, rendering the syringe disabled. The plunger extension 20 can be pulled and withdrawn but this does not act upon the 5 plunger 18.
Application of a second force (stronger than the first force) engages the second locking mechanism 44/66 between the plunger extension 20 and the plunger 18. Figure 11 is a perspective cut-away view illustrating the syringe of figure 7 with the plunger extension 20 locked with the plunger 18. Now when the plunger extension 20 is pulled it withdraws the locked 10 plunger 18, locked needled holder 14 and needle 16 back into the barrel 24. By pulling the plunger extension to its fully retracted state the needle may be fully retracted into the barrel 24 to thereby prevent the needle from being exposed. At this fully retracted state the waist 52 on the step 42 of the plunger extension 20 is exposed beyond the capturing mechanism 28 of the body 10. This allows the stem of the plunger extension 20 to be broken off to completely disable the 15 syringe with the needle safely retracted. Figure 12 is a perspective cut-away view illustrating the syringe of figure 7 after the plunger extension 20 has been pulled back and the plunger 18, needle holder 14 and needle 16 have been retracted into the barrel. The stem 42 of the plunger extension 20 has also been snapped off.
Components of a syringe made according to the present invention can be made of any 20 suitable material. For example all components could be made from a suitable thermoplastic, such as polypropylene. However in some circumstances it might be preferably to make one or more components from glass, or rubber or other medically suitable materials. If the needle mount 14 is configured to receive a needle connection fitting the end of the needle mount 14 can be capped prior to use, e.g. using a plug or the like. 25 It should be noted that the locking mechanisms described here are illustrative only and other locking mechanisms could be used with embodiments of the present invention. The examples given use a linear force (along the direction of stroke of the syringe) to engage both locking mechanisms. This is believed to be advantageous since a movement in this direction is an extension of the injecting motion already applied by a user. In fact, if the force required to 30 engage the locks is sufficiently low the user may disable the syringe without naturally at the end of the stroke without having to take any special additional action. In other embodiments one or 2012101441 21 Sep 2012 10350174 14 both of the locking mechanisms may be activated by a different force or motion, e.g. a rotating action.
It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident 5 from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

Claims (18)

1. A syringe comprising: a barrel for holding a fluid for injection; a needle holder within the barrel and located adjacent a first end of the barrel, said needle holder being configured to hold a needle extending from a first end thereof and including a first locking arrangement accessible from a second end thereof; a plunger located within the barrel such that it forms a seal with an inside surface of the barrel to enable the plunger to force fluid from the barrel via a needle as the plunger is pushed towards the first end of the barrel in use, the plunger including a first locking arrangement that is configured to cooperate with the first locking arrangement of the needle holder to lock the plunger to the needle holder; the plunger further including a second locking arrangement accessible via a second end thereof; a plunger extension, received within the barrel, said plunger extension being configured to enable the plunger to be pushed towards the first end of the barrel by applying a pushing force to the plunger extension; the plunger extension including a locking arrangement that is configured to cooperate with the second locking arrangement of the plunger to lock the plunger extension to the plunger.
2. A syringe as claimed in claim 1 wherein in use the plunger is locked to the needle holder before the plunger extension is locked to the plunger, to render the plunger inoperable to dispense or draw fluid with the syringe.
3. A syringe as claimed in any one of the preceding claims wherein, in use, when the plunger extension is locked to the plunger the needle holder may be withdrawn into the barrel to thereby withdraw a needle held thereon to be withdrawn into the barrel.
4. A syringe as claimed in any one of the preceding claims wherein the the first locking arrangement of the plunger is configured to lock with the first locking arrangement of the needle holder by a first action; and the locking arrangement of the plunger extension is configured to lock with the second locking arrangement of the plunger by a second action, wherein the second action cannot occur before the first action.
5. A syringe as claimed in claim 4 wherein the first action is the application of a first force to the plunger in a direction towards the first end of the barrel; and the second action is the application of a second force to the plunger extension in a direction towards the first end of the barrel.
6. A syringe as claimed in claim 5 wherein the first force is less than the second force and both the first force and second force are applied by a pushing force on the plunger extension.
7. A syringe as claimed in any one of the preceding claims wherein prior to the plunger extension being locked to the plunger, the plunger extension can be pulled away from the plunger without retracting the plunger.
8. A syringe as claimed in any one of the preceding clams wherein the plunger extension includes a frangible portion to enable the plunger extension to be disabled after the withdrawal of the needle into the barrel.
9. A syringe as claimed in any one of the preceding claims wherein a force required to dispense fluid from the needle in use is insufficient to cause locking of the plunger extension to the plunger.
10. A syringe as claimed in any one of the preceding claims which further includes a capture mechanism arranged to capture at least the locking arrangement of the plunger within the barrel.
11. A syringe as claimed in claim 10 wherein the capture mechanism forms part of a plunger extension guide arranged in use to guide the plunger extension within the barrel.
12. A syringe as claimed in any one of the preceding claims wherein the needle holder includes a fitting thereon arranged to receive a hypodermic needle mounted to a needle connection.
13. A syringe as claimed in any one claims 1 to 11 wherein the needle holder has a hypodermic needle mounted directly therein.
14. A syringe as claimed in any one of the preceding claims which further includes a seal to prevent leakage of fluid from the syringe prior to use.
15. A syringe as claimed in any one of the preceding claims which further includes a cap mounted adjacent the first end of the barrel to protect a needle mounted to the needle holder.
16. A syringe as claimed in any one of the preceding claims wherein the which further includes a seal to prevent leakage of fluid from the syringe prior to use.
17. A syringe as claimed in any one of the preceding claims wherein the syringe is pre-filled with a fluid to be injected.
18. A syringe as claimed in any one of the preceding claims wherein the barrel is dimensioned to allow the plunger to be pushed a predetermined stroke distance along its length to enable dispensing of a predetermined dose of fluid, and wherein the locking of the needle holder to the plunger occurs at the end of said stroke.
AU2012101441A 2012-10-25 2012-10-25 Syringe Safety Prefillable Ceased AU2012101441A4 (en)

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Application Number Priority Date Filing Date Title
AU2012101441A AU2012101441A4 (en) 2012-10-25 2012-10-25 Syringe Safety Prefillable

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