WO1991012039A1

WO1991012039A1 - Non-reusable syringe

Info

Publication number: WO1991012039A1
Application number: PCT/AU1991/000054
Authority: WO
Inventors: Alan Henry Polyblank; Alexander Stewart Richardson
Original assignee: Alan Henry Polyblank
Priority date: 1990-02-15
Filing date: 1991-02-15
Publication date: 1991-08-22

Abstract

A syringe device (10) which is not reusable after the first delivery stroke. The syringe has a hollow body (11) slidably containing a plunger (12) in fluid sealing relationship. The plunger (12) has a plunger rod (13) which includes a guide arrangement (17) receiving and guiding a locking member (18). The guide arrangement (17) is adapted to maintain the locking member (18) in an unengaged position relative to the body (11) when the plunger (12) is moved in the direction of a first intake stroke and in a first delivery stroke, and enables relative sliding movement of the locking member (18) therealong such that, upon commencement of a second intake stroke, the locking member (18) snaggingly engages the inside surface of the body (11) to resist further movement of the plunger (12) in the intake stroke direction. Accordingly, in use, the locking member (18) interacts with the guide arrangement (17) of the plunger (12) and the inside surface of the body (11) so as to allow a first intake stroke and a delivery stroke, but to prevent a second stroke of the plunger (12). The syringe device (10) may also allow for aspiration testing.

Description

NON-REUSABLE SYRINGE Field of Invention

The present invention relates to a non-reusable syringe. Description of Prior Art ϊt is well known in the art to provide a syringe having a substantially cylindrical hollow body with one end open to receive a plunger and piston arrangement, and the other end adapted to receive a hypodermic needle, cannular or the like. In such syringes, the plunger and piston are normally formed as one piece and act in sealing relationship with the inside surface of the syringe body. When a medicament or the like is to be drawn into a syringe of this known type, the plunger and piston arrangement is withdrawn in an intake stroke, and to expel the medicament the plunger and piston arrangement is moved in a delivery stroke back towards the other end of the syringe body so that the medicament is delivered via the hypodermic needle or cannular into the desired place such as a vein, organ etc.

It is nowadays desirable to prevent reuse of a syringe in certain circumstances so as to prevent communicating highly infectious diseases. The heretofore known syringes have the disadvantage that they may be refilled by subsequent withdrawal of the plunger and piston arrangement by the user, or, by pressure within a vial into which the needle of the syringe is inserted.

There have been many attempts to provide a syringe which is designed to prevent a second intake stroke and thereby render the syringe useless after the first delivery stroke. Most of the prior art devices have required a sleeve member or the like which cooperates with the plunger at least during a first intake stroke, and which prevents its operation when a second intake stroke is attempted. Although such devices can work effectively, it would be desirable, for example, to eliminate the need for the sleeve member and thereby simplify the locking mechanism. The construction of the device could also be simplified and may reduce the manufacturing cost of the syringe. Further, the syringe should preferably be able to be operated in the same manner as heretofore known syringes, and should allow techniques such as aspiration testing which allows the user to ensure, depending on what is being injected and where, that he has, or has not, found a vein or artery. Summary of the Invention

One broad form of the present invention provides a syringe device comprising: a generally hollow body slidably containing a plunger end of a plunger in fluid sealing relationship; the plunger further comprising a plunger rod attached at one end to the plunger end for slidably moving the plunger end along and within the hollow body; wherein the plunger rod comprises guide means receiving and guiding a locking member; and wherein, in use, the guide means functions to maintain the locking member in an unengaged position when the plunger is moved in the direction of a first intake stroke and in a first delivery stroke, and enables relative sliding movement of the locking member therealong such that, upon commencement of a second intake stroke, the locking member snaggingly engages the inside surface of the body to resist further movement of the plunger in the intake stroke direction. Preferably, the locking member is in frictional sliding engagement with the inside surface of the body and comprises at least one snag projection.

Preferably, the guide means has a first stop means against which the locking member bears during the first intake stroke, a second stop means spaced from said first stop means and against which the locking member bears during the delivery stroke, and a slide means extending between the stop means along which the locking member slides during use of the syringe device Furthermore, it is preferable that the first stop means causes the locking member to be orientated at a first angle with respect to a longitudinal axis of the plunger rod during the first intake stroke, the second stop means causes the locking member to be orientated at a second angle with respect to the longitudinal axis which is greater than said first angle, and wherein the guide means has an interference portion which causes the locking member to pivot further away from the longitudinal axis and thereby snaggingly engage the inside surface of the hollow body when a second intake stroke is started. Preferably the interference portion is spaced from the second stop means so as to allow for aspiration testing of the syringe device.

Alternatively, in the above defined broad form of the invention, the guide means may comprise: a sleeve member which retains the locking member adjacent a first stop means during the first intake stroke, with the locking member bearing against the first stop means during the delivery stroke; a sliding means which has a contoured portion along which the locking member slides and is caused to snaggingly engage the inside surface of the body during the second intake stroke; and a second stop face against which the locking member bears when snaggingly engaged with the inside surface for preventing the further movement of the plunger in the intake stroke direction.

Preferably, the sleeve member is caused to move in unison with the plunger and to retain the locking member during the first intake stroke, and wherein the sleeve member is caused, due to its frictional engagement with the inside surface of the body, to move along the plunger and release the locking member when the plunger is moved in a delivery stroke. Preferably, the guide means allows for a predetermined amount of movement in the second intake stroke direction before the locking member snaggingly engages the inside surface of the body for aspiration testing of the syringe device. Brief Description of the Drawings Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings, wherein:

Fig. 1 is a longitudinal-sectional view of the syringe of a first embodiment of the present invention with the plunger in the ready-for-intake position;

Fig. 2 is a longitudinal-sectional view of the syringe of Fig. 1 during the delivery stroke;

Fig. 3 is a longitudinal-sectional view of the syringe of Figs. 1 or 2 when the plunger has been returned to the ready-for-intake position after the delivery stroke;

Fig. 4 is a longitudinal-sectional view of the syringe of Figs. 1, 2 or 3 where a second intake stroke of the plunger has been started;

Fig. 5 is a cross-sectional view of the syringe of Fig. 1;

Fig. 6 is a cross sectional view of the syringe of Fig. 4;

Fig. 7 is a longitudinal sectional view of the syringe of a second embodiment of the present invention with the plunger in the ready-for-intake position;

Fig. 8 is a longitudinal sectional view of the syringe of Fig. 7 during the delivery stroke;

Fig. 9 is a longitudinal sectional view of the syringe of Figs. 7 or 8 when the plunger has been returned to the ready-for-intake position after the delivery stroke; Fig. 10 is a longitudinal sectional view of the syringe of Figs. 7, 8 or 9 where a second intake stroke of the plunger has been started; and

Fig. 11 is a cross-sectional view of the syringe of Fig. 7.

Preferred Embodiments of the Invention

There is shown in the Figs. 1-6 a syringe 10 comprising a cylindrical body 11, a plunger 12 having a plunger rod 13 and a piston member 14 which is in fluid sealing relationship with the inside surface of the body 11. A needle or cannula or the like (not shown) may be mounted or attached to a forward end of the body 11, and which fluidly communicates with the space 16 defined by the internal recess of the body 11 and the piston member 14.

The piston member 14 and the plunger shaft 13 may be separate pieces secured together on assembly of the syringe 10, or alternatively may be a single integral member. The needle may be permanently attached to the body 11 or may be detachable therewith.

The plunger rod 13 is specially formed to provide a guide arrangement 17 for a locking member 18 which is movably mounted in the guide arrangement 17.

The locking member 18 is generally planar with a lower central recess 19, upper snag projections 20 and side edges 21.

The guide arrangement 17 comprises a first stop face 22 at the piston end of the guide arrangement 17, a second stop face 26 at the opposite end 27 of the guide arrangement 17, and a guide rail 28 extending between the two faces 22, 26. There is also provided a step 29 extending from the first stop face 22, generally parallel to, and below the upper surface of the guide rail 28. The end face 31 of the step 29 is located between the two stop faces 22, 26 in the longitudinal direction of the plunger shaft 13, and extends transversally downwards with respect to the longitudinal axis 1 of the plunger rod 13.

The first stop face 22 extends at a first angle 'A' with respect to the axis 1, and the second stop face 26 extends at a second angle 'B' with respect to the axis 1. The recess 19 of the locking member 18 receives the guide rail 28, and the upper edge 30 of the recess 19 is caused to rest on the rail 28. The side edges 21 are curved and are in frictional contact with the inside surface of the cylinder 11. This arrangement allows the locking member 18 to pivot about an axis 2 generally normal to the longitudinal axis 1 of the plunger rod 13

The angle 'A' of the first stop face 22 is less than the angle *B' of the second stop face 26. The locking member 18 is configured such that at a predetermined snag angle 'C, the snag projections 20 snaggingly engage the inside surface of the cylinder 11. The snag angle 'C is greater than angle 'B' .

The locking member 18 is movable in the guide arrangement 17 between a first unengaged position adjacent the first stop face 22 (refer Fig. 1), a second unengaged position adjacent the second stop face 26 (refer Fig. 2) and a third engaged position when the end face 31 of the step 29 engages the bottom edges 32 of the locking member 18 when a second intake stroke is attempted. (Refer Fig. 4).

For the syringe 10 to be useful as a non-reusable device, it is essential that the plunger cannot be fully withdrawn and separated from the cylinder 11 as this would allow removal of the locking member 18. Accordingly, there is provided stops (not shown) which prevent full withdrawal of the plunger 12 from the cylinder 11. These stops are formed after insertion of the plunger 12.

In use, the syringe 10 is assembled such that the plunger 12 is in the ready-for-intake position and the locking member 18 is positioned adjacent the first stop face 22. In this position, the bottom edges 32 of the locking member 18 are adjacent the step 29, the curved side edges 21 of the locking member contact the inside surface of the cylinder 11, and the locking member 18 lies generally parallel to the first stop face 22. In this first position, the snag projections 20 are spaced from the inside surface of the cylinder 11. The locking member 18 retains this position relative to the guide arrangements 17 during the first intake stroke.

When the plunger 12 is moved in a delivery stroke back towards to ready-for-intake position, the locking member 18 slides along the guide rail 28 by virtue of its frictional engagement with the inside surface of the cylinder 11, and retains its orientation (i.e. angle 'A') with respect to the plunger axis 1 until it hits the second stop face 26. When it reaches the second stop face 26, the locking member 18 is caused to pivot and lie against the second stop face 26 at the second orientation angle 'B'. In this position, the snag projections 20 are still spaced from the inside surface of the cylinder 11, but the bottom edges 32 of the locking member 18 are now spaced, in the same radial direction further from the axis 1 than is the step 29. When the plunger 12 is moved in a second intake stroke back towards the ready-for-delivery position, a short movement of the plunger 12 brings the end face 31 of the step 29 into engagement with the bottom edges 32 of the locking member 18, which causes further pivotal movement of the locking member 18 about its pivot axis 2, and which brings the snag projections 20 into snagging engagement with the inside surface of the cylinder 11 thereby preventing further movement of the plunger 12 with respect to the cylinder 11. That is, the locking member 18, when it engages the inside surface of the cylinder 11, is caused to bear against the top of the rail guide 28 which forces the plunger 13 to also bear against the inside surface of the cylinder 11 opposite the snag projections 20. When the snag projections 20 engage the inside surface of the cylinder 11, this renders the syringe 10 useless. That is, any further force applied to move the plunger 12 in the second intake stroke is translated into a moment force on the locking member 18 which in turn causes the snag projections 20 to bear more forcefully against the inside surface of the cylinder 11. This arrangement allows for normal techniques generally employed during the use of a syringe as, for example, a hypodermic device. That is, medical staff, when using the syringe as a hypodermic device, first intake a medicament through the needle by withdrawing the plunger 12 from the cylinder 11 in the first intake stroke. Alternatively, the needle is inserted into a pressurized source of medicament which in turn pressurizes the space 16 of the cylinder 11 and forces the plunger 12 to withdraw in an intake stroke. When the desired dosage of medicament is within the space 16 of the syringe 10, the user may then remove any air from the syringe 10 by holding the needle end upwards, tapping the syringe to cause the air to move towards the needle and pushing the plunger 12 a short distance (i.e. a short delivery stroke) to expel the air. The person may then insert the needle hypodermically into a vein or tissue of the patient depending on what is being injected. To test whether the needle is in fact located within a vein or, alternatively, is not in a vein or an artery, the user may withdraw the plunger a short distance enough to sight blood in the syringe 10 (i.e. a short intake stroke) commonly called aspiration testing. The medicament would then be delivered into the desired location by pushing the plunger 13 in a delivery stroke. The fact that the locking member 18, in the initial movement of the plunger 13 in the first delivery stroke, may generally retain its first orientation angle 'A' before it hits the second stop face 26, allows for such techniques and specifically the combination of removing the air from the syringe followed by aspiration testing.

That is, a short delivery stroke for removing any air from the syringe 10 will move the locking member 18 away from the first stop face 22 to a position near or against the second stop face 26. Aspiration testing will then cause relative 10 movement of the locking member 18 away from the second stop 26 with the guide means allowing relative movement at least back to the front face 31 of the step 29, and if the locking member remains in the first orientation angle 'A' , may also allow movement back to the first stop face 22 15 without the step 29 causing the locking member 18 to rotate and snaggingly engage the inside surface of the cylinder. The distance 'x' between the second stop face 26 and the front face 31 of the step 29 will normally be greater than the length of the short intake stroke for aspiration testing. Accordingly, even if the locking member 18 hits the second stop face 26 and pivots into the second orientation angle 'B' when air is expelled during a short delivery stroke, the distance 'x' will be greater than the relative movement of the locking member during aspiration testing.

There is shown in Figs. 7-11 a syringe 40 comprising a cylindrical body 41, a plunger 42 having a plunger rod 43 and a piston member 44 which is in fluid sealing relationship with the inside surface of the body 41. A needle or cannular or the like (not shown) may be mounted or attached to a forward end of body 41 and which fluidly communicates with the space 46 defined by the internal recess of the body 41 and the piston member 44. The piston member 44 and the plunger rod 43 may be separate pieces secured together on assembly of the syringe 40, or alternatively may be a single integral member. The needle or mounting arrangement for the cannular may be permanently attached to the body 41 or may be detachable therewith.

The plunger rod 43 is specially formed to provide a guide arrangement 47 which extends longitudinally of the plunger rod 43. A locking member 48 is movably mounted in the guide arrangement 47. The locking member 48 has a zig zag shape in the longitudinal section which, in use, cooperates with the guide arrangement 47. The locking member 48 also has snag projections 50 at one end which project transversely away from the longitudinal axis of the plunger 42, and rearwardly of the syringe 40.

The guide arrangement 47 comprises a sliding face 62, a first stop face 51 at one end of the sliding face 62 distal from the piston member 44, a second stop face 53 at the other end of the sliding face 62, and a contoured portion 52 on the sliding face 62 intermediate of the stop faces 51, 53.

The plunger rod 43 further comprises a projection 54 on an opposite side of the guide arrangement 47. The syringe 40 further comprises a sleeve member 55 which is slidably received in the body 41, but which is in frictional contact with the inside surface thereof.

The syringe 40 is assembled such that the plunger 42 is in a ready-for-intake position with the piston member 44 adjacent the forward end of the body 41. In that position, the locking member 48 is in a non-engaged position on the sliding face 62 adjacent the first stop face 51 and straddling the contoured portion 52. The sleeve member 55 is adjacent the projection 54 and has a tab means 56 which bears against the snag projections 50 of the locking member 48 thereby preventing their engagement with the inside surface of the body 41.

In use, the plunger 42 may be withdrawn from the body 41 so as to induct a fluid such as, for example, a medicament into the space 46. During the intake stroke, the sleeve member 55 is caused to remain in the same relative position with respect to the plunger rod 43 by bearing against the projection 54, and the locking member 48 is also caused to remain in the same relative position with respect to the guide arrangement 47 by the tab means 56 on the sleeve member 55.

In this position, the sleeve member 55 keeps the projection 54 of the plunger rod 42 spaced from the inside surface, and also serves to position and align the plunger rod 43 with the longitudinal axis of the body 41 during the first intake stroke.

When the plunger 42 has been withdrawn so as to intake the desired amount of fluid into the space 46, it is then in the ready-for-delivery position. The plunger 42 can then be pushed back into the body 41 in a delivery stroke so as to expel the fluid through the syringe, cannular or the like.

Due to its frictional engagement with the inside surface of the body 41, the sleeve member 55 is caused to remain in the same position relative to the body 41 during the delivery stroke. However, the locking member 48 is caused to remain in the same relative position with respect to the guide arrangement 47 since it bears against the first stop face 51 during the delivery stroke. Accordingly, when the plunger 42 has been moved in the delivery stroke, the locking member 48 moves relative to and away from the sleeve member 55 so as to be released from the tab means 56. When the locking member 48 is sufficiently spaced from the sleeve member 55, the snag projections 50 face the inside surface of the body 41. Further, when the plunger 42 is moved in the delivery stroke, the bottom edge 60 of the plunger rod 42, which is slightly curved towards the longitudinal axis of the plunger rod, is spaced from the inside surface 61 of the sleeve member 55 thereby allowing slight misalignment of the longitudinal axis of the plunger rod 42 and the body 41 such that the projection 54 also bears against the inside surface of the body 41.

When the plunger 42 is then moved in a second intake stroke, the locking member 48 will slide along the sliding face 62 a predetermined distance A before riding up the inclined face 58 of the contoured portion 52 whereupon the snag projections 50 will be moved into snagging engagement with the inside surface of the body 41. The locking member 48 bears against the inclined face 58 whilst the projection 54 bears against the inside surface generally opposite from the snag projections 50 thereby preventing further movement of the plunger 42 in the second intake stroke direction.

The guide arrangement 47 is designed to allow the locking member 48 to move therealong the predetermined distance A (defined by the distance between the stop face 50 and the inclined face 58 of the contoured portion 52) during the second intake stroke before the locking member 48 engages the inside surface. This allows the user to perform aspiration testing to ensure, for example, that the needle is/is not within a vein or artery.

It will be recognized by persons skilled in the art that numerous variations and modifications may be made to the invention as described above without departing from the scope or spirit of the invention as broadly described.

Claims

1. A syringe device comprising: a generally hollow body slidably containing a plunger end of a plunger in fluid sealing relationship; the plunger further comprising a plunger rod attached at one end to the plunger end for slidably moving the plunger end along and within the hollow body; wherein the plunger rod comprises guide means receiving and guiding a locking member; and wherein, in use, the guide means functions to maintain the locking member in an unengaged position when the plunger is moved in the direction of a first intake stroke and in a first delivery stroke, and enables relative sliding movement of the locking member therealong such that, upon commencement of a second intake stroke, the locking member snaggingly engages the inside surface of the body to resist further movement of the plunger in the intake stroke direction.

2. The syringe device of claim 1 wherein the locking member is in frictional sliding engagement with the inside surface of the body and comprises at least one snag projection.

3. The syringe device of claim 1 or 2 wherein the guide means has a first stop means against which the locking member bears during the first intake stroke, a second stop means spaced from said first stop means and against which the locking member bears during the delivery stroke, and a slide means extending between the stop means along which the locking member slides during.use of the syringe device.

4. The syringe device of claim 3 wherein the first stop means of the guide means causes the locking member to be orientated at a first angle with respect to a longitudinal axis of the plunger rod, the second stop means causes the locking member to be orientated at a second angle with respect to the longitudinal axis which is greater than said first angle, and wherein the guide means further comprises an interference portion which causes the locking member to pivot further away from the longitudinal axis and thereby snaggingly engage the inside surface of the body during a second intake stroke.

5. The syringe device of claim 4 wherein the interference portion is spaced from the second stop means so as to allow for aspiration testing of the syringe device.

6. The syringe device of claims 1 or 2 wherein the guide means comprises: a sleeve member which retains the locking member adjacent a first stop means during the first intake stroke, with the locking member bearing against the first stop means during the delivery stroke; a sliding means which has a contoured portion along which the lock member slides and is caused to snaggingly engage the inside surface of the body during the second intake stroke; and wherein the contoured portion defines a second stop face against which the locking member bears when snaggingly engaged with the inside surface for preventing the further movement of the plunger in the intake stroke direction.

7. The syringe device of claim 6 wherein the sleeve member is caused to move in unison with the plunger and to retain the locking member during the first intake stroke, and, due to a frictional engagement with the inside surface, is caused to move along the plunger rod and release the locking member when the plunger is moved in the delivery stroke.

8. The syringe device of claims 6 or 7 wherein the contoured portion has an inclined surface which guides the locking member into the snagging engagement with the inside surface, the inclined surface having a leading edge which is spaced from the first stop means so as to allow for aspiration testing of the syringe device.