WO1991016096A1

WO1991016096A1 - Single-use syringe

Info

Publication number: WO1991016096A1
Application number: PCT/AU1991/000158
Authority: WO
Inventors: Gilbert Henry Banks
Original assignee: Isb (R&D) Pty. Limited
Priority date: 1990-04-19
Filing date: 1991-04-19
Publication date: 1991-10-31

Abstract

A single use syringe having a control device (see fig. 8) and a control mechanism, one of each attached to the syringe body and the other attached to the plunger, whereby, in use, firstly, a single withdrawal stroke (28) is enabled allowing supply of injection fluid to within the syringe, secondly, the plunger is rotated (29) relative to the syringe body, and, finaly, a single injection stroke (32) is enabled whereby the plunger is pushed into the syringe body to consequently eject the injecting fluid. The control device is preferably of x-shaped configuration, and the control mechanism is preferably a u-shaped path (about the longitudinal axis of the syringe) of a saw-tooth shape.

Description

SINGLE-USE SYRINGE

The present invention relates to a single-use syringe, and in particular, to a syringe which has improved tamper proof qualities, such that forceful use beyond an initial use of the syringe is obviated.

Hypodermic needles for injecting fluids into the human body are extensively used in hospitals and throughout the medical profession in order to administer drugs. Unfortunately, such hypodermic needles are additionally used by drug addicts to administer illicit drugs.

In all instances, it is intended that hypodermic syringe needles be utilised only once. A hypodermic needle is supplied in a sterile condition from the manufacturer, and after a single-use, this sterile condition no longer exists. The hypodermic needle should then be discarded.

In recent years, the AIDS epidemic amongst homosexuals, and now the community in general, has caused Governments to look seriously into the problem of drug addicts re-using hypodermic needles and thereby spreading the AIDS disease. The major problem which allows the spread of the AIDS disease is that previously used syringes are utilised for the administration of the illicit drugs. The needle, having been previously infected by the AIDS virus, consequently passes the disease on to the subsequent user of the needle.

The present invention seeks to provide a single-use syringe, which consequently eliminates the possibility of transfer of the AIDS virus from person to person.

The present invention also seeks to provide a single-use syringe, which, due to its unique design characteristics, prevents a user from tampering with the needle and/or syringe components such that the possibility of reuse of the needle/syringe is obviated.

The present invention also seeks to provide a single-use syringe, whereby a single withdrawal and then insertion stroke is enabled for the supply of an injecting fluid into the syringe, and ejection of the injecting fluid from the syringe, respectively.

In one broad form the present invention provides a single-use syringe, comprising: a syringe body, adapted to receive a hypodermic needle at a first end thereof; a plunger, adapted to be received within said syringe body; a control device adapted to be contained either within said syringe body or on said plunger, intermediate the ends thereof; a control mechanism, provided either on said plunger or within said syringe body, respectively, adapted to cooperate with said control device; whereby, in use: a single withdrawal stroke is enabled, whereby said plunger is withdrawn from said body, allowing supply of injection fluid to within said syringe; said plunger is then rotated relative to said syringe body; and, a single injection stroke is enabled whereby said plunger is reinserted within said syringe body, ejecting said injecting fluid from said syringe body.

Preferably, the single-use syringe as hereinabove defined is embodied wherein said control mechanism is a moulded path provided either on the exterior surface of said plunger or the interior surface of said body, said path being substantially U or V shaped about the longitudinal axis of said plunger; said control device being adapted to engage with said control mechanism, such that said device is permitted to travel along said U or V-shaped path in one direction only.

Also preferably, the single-use syringe is embodied wherein said path is moulded with a plurality of shaped protrusions or steps therealong, to permit said control device to travel therealong in one direction only.

The control device is preferably embodied as a resilient member adapted to selectively cooperate with said shaped protrusion or steps, whereby said resilient member is adapted to traverse said shaped protrusions or steps in one direction but impedes the movement over said shaped protrusions or steps in the opposite direction along said path.

The shaped protrusions of the control mechanism as hereinbefore defined preferably have a first edge thereof which is substantially normal to the longitudinal axis of the syringe preventing movement, and a second edge which is provided at an inclined angle to the longitudinal axis of the syringe, enabling said resilient member to ride up and pass over said protrusions.

A preferred embodiment of the present invention also provides a single-use syringe wherein a substantially small amount of movement in the reverse direction is enabled for blood show within said syringe.

Also, in another preferred embodiment of the present invention a single-use syringe is provided wherein a piercing member is provided to pierce a membrane provided on said plunger, disallowing further withdrawal of said plunger after a single injection step.

In an optionally preferred embodiment, the single-use syringe is constructed wherein said hypodermic needle is adapted to be provided for storage within a rear end of said plunger.

In a preferred but non-limiting embodiment, said control device is substantially x-shaped.

This perferred x-shaped control device is preferably embodied wherein a first and second arms of said x-shaped control device are adapted to be retained in a shaped recess provided within said syringe body or said plunger, and a third and fourth arms of said x-shaped control device are adapted to cooperate with said control mechanism.

Also preferably, whilst said control device is in a first path protion of said control mechanism, said third and fourth arms of said x-shaped control device are adapted to ride over shaped protrusions of said control mechanism allowing said withdrawal stroke to be performed, whilst said fourth arm prevents movement in the reverse direction thereto; and whilst said control device is in a second path portion of said control mechanism, said third and fourth arms of said x-shaped control device are adapted to ride over shaped protrusions of said control mechanism allowing said injection stroke to be performed, whilst said third arm prevents movement in the reverse direction thereto.

In a preferred embodiment, said shaped protrusions are saw-tooth in shape, whereby a first inclined edge allows movement of the control device in a first direction and a second edge substantially normal to the longitudinal axis of the syringe prevents movement of the control device in a second direction.

Also preferably, whilst said withdrawal stroke is being performed, said fourth arm of said x-shaped device prevents reverse movement and, whilst said injection stroke is being performed, said third arm of said x-shaped device prevents reverse movement.

In a further broad form, the present invention also provides a method of using a single-use syringe, comprising the steps of: withdrawing said plunger from said body, allowing supply of injecting fluid within said syringe; rotating said plunger relative to said syringe body; and, reinserting said plunger within said syringe body to eject said injecting fluid from said syringe body; wherein, after said reinserting step, further movement of said plunger relative to said syringe body is substantially prevented.

Preferably, the method as hereinbefore defined is implemented wherein said rotating step may be carried out either simultaneously or separately to said withdrawing and/or reinserting steps.

The present invention will become more fully understood from the following detailed description thereof, in connection with the accompanying drawings wherein:

Fig. 1 illustrates an exploded view of a single-use syringe in accordance with the present invention;

Fig. 2 illustrates a cross-sectional view of the syringe body of Fig. 1;

Fig. 3 illustrates a first cross-sectional view of the syringe plunger, showing the fill portion of the control mechanism;

Fig. 4 illustrates a second cross-sectional view of the syringe plunger in a direction normal to the view of Fig. 3, showing the inject portion of the control mechanism;

Fig. 5 illustrates a laid-flat view of the control mechanism, and the associated fill and inject cams;

Fig. 6 illustrates various views of the control device which is utilised in conjunction with the control mechanism of Fig. 5;

Fig. 7 illustrates a sectional view through the syringe, showing the location of the control device;

Fig. 8 illustrates an alternative embodiment of a control device;

Fig. 9 illustrates the alternative control device of Fig. 8 in use, showing the functional engagement thereof with the syringe body and plunger;

Fig. 10 illustrates a laid-flat view of the control mechanism utilised in the control device of Figs. 8 and 9; and.

Fig. 11 illustrates a destructable syringe plunger in accordance with a further preferred embodiment of the present invention.

In Fig. 1, is shown a single-use syringe, comprising a body 1, a plunger 2 which is adapted to be inserted within the body 1, having a fluid tight membrane 6 disposed at a first end thereof. A needle 3 is adapted to be provided to a first end 16 of the syringe body 1. Also shown in Fig. 1 is the ability for the needle to be provided at a second end of the plunger 2, for storage thereof prior to use of the hypodermic needle syringe.

Intermediate the ends of the body 1, is provided a control device 5, which is adapted to cooperate with a control mechanism 4 provided intermediate the ends of the plunger 2. The operation of the control device and its cooperation with the control mechanism will be described in more detail hereinafter. It will however be appreciated that an alternative arrangement would be to have the control device in engagement with the plunger 2 and the control mechanism provided on the syringe body 1.

In Fig. 2 is shown a first cross-sectional view of the body 1 of the syringe, sectioned along the longitudinal axis of the syringe body 1. The cross-sectional view illustrates the end 16 to which the needle 3 is to be adapted, and the control mechanism 5 provided intermediate the ends of the body 1.

In Fig. 3 is illustrated a cross-sectional view of the plunger 2 , also shown along the longitudinal axis thereof. The plunger 2 is adapted to be provided within the body 1, shown in Fig. 2. The end of the plunger 2 is provided with a fluid tight membrane 6, which is impervious to the injecting fluid which is to be supplied within the syringe for injection to a human body or the like. Intermediate the ends of the plunger 2 is shown the control mechanism 4, and in particular, the figure illustrates the portion of the control mechanism 4 wherein the control device 5 is adapted to cooperate therewith during the filling operation of the syringe, called hereinafter, the "fill portion".

In Fig. 4 is shown a further cross-sectional view of the plunger 2, similar to that shown in Fig. 3, but in this case showing the "inject portion" of the control mechanism 4. This view is in a direction normal to the cross-sectional view of Fig. 3. It is the inject portion of t e control mechanism 4 which cooperates with the control device 5 shown in Fig. 2, such that the injection fluid may be injected into the human body or the like from the syringe .

In Fig. 5(a) is shown a laid-flat drawing of the control mechanism shown in Figs. 3 and 4. The laid-flat illustration of the control mechanism provides for an easy understanding of the operation of the control mechanism. Side views of the control mechanism are illustrated in Figs. 5(b) and 5(c). Fig. 5(a) shows how the control mechanism is a substantially U or V shaped path, through which the control device 5 may travel. That is, the control device 5 would initially start its path at the end 7 of the path. Relative to the control mechanism path, the control device then travels in the direction shown by arrow 8, until it reaches the bottom of the substantially horizontal path 9. At this point, the syringe will be filled with the injecting fluid. Then, by rotation of the syringe plunger 2 relative to the syringe body 1, the control device 5 is adapted to traverse a further portion of the path shown by arrow 10 to arrive at the portion 11 of the path. At this point, the syringe is ready for the injecting operation. Once the hypodermic needle is placed in the correct position within the human body or the like, the plunger 2 may then be pushed into the syringe body 1, the control device 5 travelling in the direction shown by arrow 12, to arrive in the final position of the path 13.

The control device 5 is only permitted to travel along one direction of the path illustrated by arrows 8, 10 and 12. Reverse travel is not permitted. This may be achieved by means of the provision of a plurality of projections, shaped as shown in Figs. 5(b) and 5(c), which may be described as saw-tooth shaped with a first inclined edge and a second edge normal to the longitudinal axis of the syringe. The projections allow a resilient member to pass in one direction, but not in the other.

In Fig. 6(a) is illustrated a plan view a suitable control device 5, which is adapted to cooperate with the control mechanism detailed in Fig. 5. The control device 5, illustrated in Fig. 6(a) is shown to be a plate like member with the ends thereof angled, as best illustrated in the sectional views shown in Fig. 6 (b) , (c) and (d) . It will be understood that the end portions 14 of the control device 5 are adapted to cooperate with the projections 15 shown in Fig. 5.

In Fig. 7 is illustrated a sectional view taken through the syringe body and plunger at a direction normal to the longitudinal axis of the syringe body and plunger, the control device location being illustrated in the diagram for ease of understanding.

In Fig. 8 is shown an alternative embodiment of such a control device, which has the advantage that it is simpler to manufacture, and has improved operational characteristics in preventing persons from tampering with the syringe.

This alternative control device, to that shown in Fig. 6 is preferably formed of an acetyl copolymer or other resilient material, preferably but not limited to plastics. The device 17 is shown to be of X-shaped cross-section. It will be understood that the end portions 18 of the control device 1 are adapted to cooperate with the projections 15 of the control mechanism.

Fig. 9 illustrates a sectional view through the syringe body and plunger, with the alternative control device 17 therein. As will be understood, referring to Fig. 8, if the control device 17 is attempted to be moved in a first direction indicated by arrow 11, then the end 9 of the control device 17 is adapted to be deformed such that the control device 17 can travel in the direction of the arrow 19. If however, the syringe plunger and the syringe body are attempted to be moved in a direction such as indicated by arrow 20, then the end 21 abuts the projection 22 such that movement is prevented.

The utilisation of this simpler control device 17 also allows for a simpler control mechanism to be utilised. The laid-flat illustration of the control mechanism, shown in Fig. 10(a), provides for an easy understanding of the operation thereof. Side views of the control mechanism are illustrated in Figs. 10(b) and 10(c). From Fig. 10, it will become understood that the control mechanism is a substantially U or V-shaped path, through which the control device (shown in Figs. 8 and 9) may travel. That is, the control device would initially start its path at the end 27 of the path. Relative to the control mechanism path, the control device 17 then travels in the direction shown by arrow 28 until it reaches the bottom of the substantially horizontal path 29. At this point, the syringe will be full of injecting fluid. Then, by rotation of the syringe plunger relative to the syringe body*, the control device 17 is adapted to transverse a further portion of the path shown by arrow 30 to arrive at the portion 31 of the path. At this point, the syringe is ready for the injecting operation. Once the hypodermic needle is placed into the correct position within the human body, or the like, the plunger may be pushed into the syringe body, the control device 17 travelling in the direction shown by arrow 32 to arrive at the final position 33.

Therefore, the control device 17 is only permitted to travel in one direction along the path 28, 30, 32. Reverse travel is not permitted. This is achieved by means of a plurality of projections 15, shaped as shown in the side views 10(b) and 10(c). These projections 15 allow a resilient control device 17 to pass in one direction, but not in the other.

It will be appreciated that the control device 17 described hereinabove has advantages over the previously described control device, in that, it is more simply manufactured, the tolerances thereof being less critical, and it is cheaper to manufacture, particularly from acetyl copolymer. Furthermore, less jagged movement is enabled between the syringe plunger and syringe body by easy deformation of the resilient member 17.

A further preferred option of the present invention is to provide a destructable portion. Fig. 11 illustrates a side elevational view of a plunger 23 having a handle portion 24 at one end thereof and a piston portion 25 at an adjacent end thereof. Intermediate the ends is provided a weakened portion 26 which, if the handle 24 of the plunger 23 is attempted to be forcably pulled relative to the fixed piston end of the plunger 25, the handle portion 24 is adapted to tear away from the piston portion 25. This may be enabled by, at the position indicated by arrow 26, providing perforations or some other weakened portion in the plunger. That is, if a person attempts to overcome the force required to move the plunger outwardly of the syringe body, then the handle portion 24 is torn away preventing further forcable removal. Obviously, the weakened portion is provided such that it will not tear away"upon normal withdrawal of the plunger travelling along its path, but only when extra force is provided as would be required to withdraw the plunger from the body along its path in the opposite direction thereto.

Various other alterations and modifications may be incorporated with the single use syringe as previously described. For example, a piercing spigot 16 (see Fig. 1) may be optionally provided, adapted to pierce the membrane 6 after a single injection. This is a feature which may additionally be provided to ensure complete destruction of the syringe, consequently preventing further use.

It will be understood that, by the unique provision of the control device and control mechanism provided at intermediate points of the body 1 and plunger 2, even full withdrawal of the plunger from the body, in at least as much as full withdrawal is allowed, will not enable the control mechanism nor the control device 5 to be accessed by an operator. Consequently, this avoids the possibility that the control mechanism 4 or control device 5 could be tampered with, such as a person scraping or filing the projections 15, such that direction in the reverse path illustrated by numerals 8, 10 and 12 is permitted.

Another feature of the present invention is that a small amount of free movement, for example one millimetre, is permitted for blood show. - li ¬ lt will be understood to persons skilled in the art that other embodiments of the control mechanism and control device will become obvious. Such embodiment should however be considered to fall within the spirit and scope of the present invention.

For instance, rather than providing a U-shaged path as shown by arrows 8, 10 and 12, a V-shaped path may be provided wherein, during the fill and inject operations, a small amount of rotation between the body and the plunger is enabled.

It will become obvious to persons skilled in the art that numerous other variations and modifications are also envisaged to the present invention. Such variations and modifications should be considered to fall within the scope of the present invention as broadly described hereinbefore and as claimed hereinafter.

Claims

THE CLAIMS :

1. A single-use syringe, comprising: a syringe body, adapted to receive a hypodermic needle at a first end thereof; a plunger, adapted to be received within said syringe body; a control device adapted to be contained either within said syringe body or on said plunger, intermediate the ends thereof; a control mechanism, provided either on said plunger or within said syringe body, respectively, adapted to cooperate with said control device; whereby, in use: a single withdrawal stroke is enabled, whereby said plunger is withdrawn from said body, allowing supply of injection fluid to within said syringe; said plunger is then rotated relative to said syringe body; and, a single injection stroke is enabled whereby said plunger is reinserted within said syringe body, ejecting said injecting fluid from said syringe body.

2. A single-use syringe as claimed in claim 1, wherein: said control mechanism is a moulded path provided on the exterior surface of said plunger or the interior surface of said body, said path being substantially U or V shaped about the longitudinal axis of said plunger; said control device being adapted to engage with said control mechanism such that said device is permitted to travel along said U or V shaped path in one direction only.

3. A single-use syringe as claimed in claims 1 or 2, wherein said path is moulded with a plurality of shaped protrusions or steps therealong, to permit said control device to travel therealong in one direction only.

4. As single-use syringe as claimed in claim 3, wherein said control device is a resilient member adapted to selectively cooperate engage with said shaped protrusions or steps, whereby said resilient member is adapted to traverse said shaped protrusions or steps in one direction but is impeded from movement over said shaped protrusions or steps in the opposite direction along said path.

5. A single-use syringe as claimed in claim 4, wherein said shaped protrusions have a first edge thereof which is substantially normal to the longitudinal axis of the syringe preventing movement, and a second edge which is provided at an inclined angle to the longitudinal axis of the syringe, enabling said resilient member to ride up and pass over said protrusions.

6. A single-use syringe as claimed in any one of claims 1 to 5, wherein a substantially small amount of movement in the reverse direction is enabled for blood show within said syringe.

7. A single-use syringe as claimed in any one of claims 1 to 6, wherein a piercing member is provided to pierce a membrane provided on said plunger, disallowing further withdrawal of said plunger after a single injection step.

8. A single-use syringe as claimed in any one of claims 1 to_β 7, wherein said hypodermic needle is adapted to be provided for storage within a rear end of said plunger.

9. A single-use syringe as claimed in any one of claims 1 to 8, wherein said control device is substantially x-shaped.

10. A single-use syringe as claimed in claim 9, wherein, the first and second arms of said x-shaped control device are adapted to be retained in a shaped recess provided within said syringe body or said plunger, and the third and fourth arms of said x-shaped control device are adapted to cooperate with said control mechanism.

11. A single use syringe as claimed in claim 10, wherein: whilst said control device is in a first path protion of said control mechanism, said third and fourth arms of said x-shaped control device are adapted to ride over shaped protrusions of said control mechanism allowing said withdrawal stroke to be performed, whilst said fourth arm prevents movement in the reverse direction thereto; and whilst said control device is in a second path portion of said control mechanism, said third and fourth arms of said x-shaped control device are adapted to ride over shaped protrusions of said control mechanism allowing said injection stroke to be performed, whilst said third arm prevents movement in the reverse direction thereto.

12. A single use syringe as claimed in claim 11, wherein said shaped protrusions are saw-tooth in shape, whereby a first inclined edge allows movement of the control device in a first direction and a second edge substantially normal to the longitudinal axis of the syringe prevents movement of the control device in a second direction.

13. A single use syringe as claimed in claim 12, wherein: whilst said withdrawal stroke is being performed, said fourth arm of said x-shaped device prevents reverse movement; and, whilst said injection stroke is being performed, said third arm of said x-shaped device prevents reverse movement.

14. A method of using a single-use syringe, comprising the steps of: withdrawing said plunger from said body, allowing supply of injecting fluid within said syringe;

.rotating said plunger relative to said syringe body; and reinserting said plunger within said syringe body to eject said injecting fluid from said syringe body; wherein, after said reinserting step, further movement of said plunger relative to said syringe body is substantially prevented.

15. A method as claimed in claim 9, wherein said rotating step may be carried out either simultaneously or separately to said withdrawing and/or reinserting steps.