WO2006086825A1

WO2006086825A1 - Improved needle assembly

Info

Publication number: WO2006086825A1
Application number: PCT/AU2006/000046
Authority: WO
Inventors: Frank Popovsky
Original assignee: Biomd Ltd
Current assignee: Biomd Ltd
Priority date: 2005-01-17
Filing date: 2006-01-17
Publication date: 2006-08-24
Anticipated expiration: 2007-07-17

Abstract

An improved needle assembly (8) includes an elongate needle mount (10), a needle (12), and a sheath (14) mounted on the elongate needle mount (10) for reciprocal axial movement between a forward position whereat the sheath (14) covers the needle (12) and a rearward position whereat the needle (12) is exposed. The needle assembly (8) can be mounted on a conventional syringe.

Description

"IMPROVED NEEDLE ASSEMBLY"

Technical field

This invention relates to an improved needle assembly suitable for use with a conventional syringe.

Background of Invention

It is desirable to protect a needle with a sheath after use in order to prevent needle-stick injuries, and also to ensure that the. needle cannot be re-used. To this end, the prior art is crowded with a multitude of syringes having sheaths mounted thereon which can be locked in a post-use position in which the needle is covered by the sheath.

The present invention is an improvement of the invention disclosed in International Patent Application PCT/AU2003/000617 published on 4 March 2004 under Publication Number WO 2004/018024. The invention disclosed in PCT/AU2003/000617 involved a needle assembly in which the protective sheath was mounted for reciprocation on the needle assembly, rather than on the barrel of the syringe. As such, it enabled the continued use of conventional syringes. PCT/AU2003/000617 is hereby incorporated in its entirety by cross reference.

Summary of Invention

The present invention provides an improved needle assembly as defined in the following claims. Preferred features of the improved needle assembly will be apparent from the following description of a preferred embodiment of the invention. Description of Drawings

In order that this invention may be more easily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention, wherein -

FIG 1 is an exploded perspective view of an improved needle assembly according to the present invention,

FIG 1 A is an enlarged view of a portion of FIG 1 ,

FIG 2A is a perspective view of the improved needle assembly with the sheath in the pre-use, needle-protected position,

FIG 2B is a perspective view of the improved needle assembly with the sheath in the ready-for-use, needle-exposed position,

FIG 2C is a perspective view of the improved needle assembly in the post-use, sheath- released/needle-exposed position,

FIG 2D is a perspective view of the improved needle assembly in the post-use, needle- protected position,

FIG 3A is a section view taken along line 3A-3A in FIG 2A,

FIG 3B is a section view taken along line 3B-3B in FIG 2B, FIG 3C is a section view taken along line 3C-3C in FIG 2C;

FIG 3D is a section view taken along line 3D-3D in FIG 2D;

FIG 4A is a section view taken along line 4A-4A in FIG 2A;

FIG 4B is a section view taken along line 4B-4B in FiG 2B;

FIG 4C is a section view taken along line 4C-4C in FIG 2C;

FIG 4D is a section view taken along line 4D-4D in FIG 2D;

FIG 5 is a section view of a second embodiment of an improved needle assembly according to the present invention;

FIG 6 is a section view of the sheath of the second embodiment, together with a left hand side elevation of the sheath;

FIG 7 is a partly sectioned view of the needle mount of the second embodiment; and

FIG 8 is another partly sectioned view of the needle mount of FIG 7 rotated through 90 degrees about its longitudinal axis.

Description of Preferred Embodiment of Invention With reference firstly to FIG 1 , there is illustrated an exploded perspective view of a needle assembly 8 according to the present invention The needle assembly 8 includes an elongate needle mount 10, a needle 12 extending forwardly in an axial direction from the needle mount 10 and a sheath 14 which in use is mounted for axial reciprocation on the needle mount 10 A compression spring 15 is disposed intermediate the sheath 14 and needle mount 10, the compression spring biasing the sheath 14 in a forward direction

Typically, the components of the needle assembly, with the exception of needle 12 and compression spring 15, will be manufactured from plastics material Needle 12 and compression spring 15 will typically be manufactured from a metal material

The needle mount 10 has a rearward frusto-conical portion 16 which terminates in a flange 17 The rearward frusto-conical portion 16 is adapted to receive the forward frusto-conical end of a conventional syringe (not illustrated) which will typically consist of a barrel and plunger assembly The needle 12 may extend rearwardly into the interior of the frusto-conical portion 16 such that the forward end of a pre-filled and sealed syringe may be punctured during assembly of the needle assembly 8 with the syringe

Forward of the frusto-conica) portion 16 is a circular-cross-section portion 18 Immediately forward of the circular-cross-section portion 18 is a rectangular-cross- section portion 20 Forward of rectangular-cross-section portion 20 is a generally cylindrical portion 22, with the needle 12 and compression spring 15 extending from the forward end of the generally cylindrical portion 22

The rectangular-cross-section portion 20 defines four sides comprising a pair of lateral sides (also referred to herein as a "first pair of opposed sides"), and upper and lower sides (also referred to herein as a "second pair of opposed sides"). The lateral or first pair of opposed sides are spaced apart by an amount greater than the spacing between the upper and lower or second pair of opposed sides.

Still referring to FIG 1 , the sheath 14 includes opposed tabs 28 for engagement by the fingers of the person using the needle assembly, and the rearward end of the sheath 14 terminates in a bifurcated arrangement which defines a pair of laterally flexible resilient members 30. Each resilient member 30 includes a forwardly-facing surface 31 , an inwardly-facing surface 32 which in use engages the sides of square-cross-section axial portion 20. and a rearwardly-facing surface 33 (not directly visible in FIG 1 ). The rear end of each resilient member 30 also includes a radially-extending recess or slot 29 which co-operates with projections provided of the needle mount as will be described hereunder.

Turning again to the needle mount 10, the complex contours intermediate the rectangular-cross section portion 20 and cylindrical portion 22 will now be described with reference to FIG 1 A.

The forward end of each of the lateral or first pair of opposed sides of the rectangular- cross-section portion 20 includes a radially-extending projection 38 straddled on either side by a convex ramp 39. The lower of the two convex ramps is not visible in FIG 1A. With additional reference to FIG 2A, the needle assembly is shown in the pre-use, needle-protected position. In this position, the sheath 14 is biased in a forward direction relative to the needle mount 10 by compression spring 15. The sheath 14 is prevented from disengaging from the needle mount 10 in the forward direction by virtue of the engagement of the forwardly-facing surface 31 of the sheath 14 with the rearwardly- facing surface 42 of the needle mount 10 which is not directly visible in FIG 1A. When the sheath is in the pre-use, needle-protected position illustrated in FIG 2A, the radially-extending projections 38 on the needle mount 10 are engaged with the radially- extending recesses 29 on the sheath 14, such that it is impossible to rotate the sheath 14 relative to the needle mount 10 about the axis Additionally, the engagement of the convex ramps 39 of the needle mount 10 with at least the edges of the rearwardly- facing surfaces 33 on the sheath 14 means that rearward movement of the sheath 14 relative to the needle mount 10 is releasably resisted in this regard, if sufficient rearward force is applied to the sheath 14, then the opposed resilient members 30 of the sheath 14 will resiliency spread apart as the edges of the rearwardly-facing surfaces 33 travel over the convex ramps 39

In summary, when the sheath is in the pre-use, needle-protected position shown in FIG 2A rotation of the sheath 14 relative to the needle mount 10 is not possible, and rearward movement of the sheath 14 relative to the needle mount 10 is only possible in response to application of sufficient force to cause the sheath 14 to travel rearwardly over the convex ramps 39 It is not essential that the ramps be convex, but it is preferred as this arrangement increases initial resistance to rearward movement of the sheath, compared to an equivalent linear ramp

Turning now to FIG 2B, the sheath 14 has moved rearwardly relative to the needle mount 10 to a position whereat the needle 12 is exposed and ready for use During the rearward travel of the sheath 14 relative to the needle mount 10, the compression spring 15 has been compressed and the inwardly-facing surfaces 32 have slid along the lateral or first pair of opposed sides of the rectangular-cross-section portion 20 Once the inwardly-facing surfaces 32 of the resilient members 30 have passed over the rearward ends of the lateral or first pair of opposed sides of the rectangular-cross- section axial portion 20, they snap inwardly to a position whereat the inwardly-facing surfaces 32 engage the circular-cross-section portion 18 of the needle mount 10 Concurrently, the forwardly-facing surfaces 31 of sheath 14 engage the rearward-facing surfaces 27 (not directly visible in FIG 1A) of the rectangular-cross-section portion 20 such that the sheath 14 cannot move in the forward direction relative to the needle mount 10

In the position shown in FIG 2B, the radially-extending recesses or slots 29 provided in the rear end of sheath 14 also releasably engage with detents 40 provided at the rearward end of each of the lateral or first pair of opposed sides As can be seen, each detent 40 consists of a small projection which extends in the rearward direction from the rear-facing surface 27 The engagement of the detents 40 with the recesses 29 causes the sheath 14 to be releasably retained in the position shown in FIG 2B It is however possible to rotate the sheath 14 through 90 degrees relative to the needle mount 10 in order to arrive at the orientation shown in FIG 2C However, rotation from the orientation shown in FIG 2B is releasably resisted by the inter-engagement of detents 40 and recesses 29 Application of sufficient rotative force to the sheath 14 will cause the sheath 14 to move slightly rearwardiy relative to the needle mount 10 such that the detents 40 and slots or recesses 29 dis-engage and the sheath may then rotate to the orientation shown in FIG 2C

The shield 14 can be rotated in either direction relative to the needle mount 10 in the illustrated embodiment In other embodiments the circular-cross-section portion 18 may be only partially circular in cross-section (eg two opposed quadrants are circular) such that the shield 14 can only rotate in one direction relative to the needle mount 10 When the sheath 14 reaches the rotative position shown in FIG 2C₁ it is then free to move in the forward direction under the influence of the compression spring 15 to the position shown in FIG 2D

During forward travel of the sheath 14 relative to the needle mount 10, the compression spring 15 expands and the inwardly-facing surfaces 32 of the needle mount 14 slide along the upper and lower or second pair of opposed sides of the rectangular-cross- section portion 20 of the needle mount 10 As the sheath 14 reaches the forward position illustrated in FIG 2D, the resilient members 30 are spread apart as the inwardly- facing surfaces 32 pass over ramps 26 Of course, the compression spring 15 must be strong enough to ensure that the resilient members 30 pass over ramps 26

After passing over the ramps 26, the resilient members 30 snap inwardly such that inwardly-facing surfaces 32 engage outwardly-facing surfaces 36 provided on the needle mount 10 Subsequent rearward movement of the sheath 14 relative to the needle mount 10 is prevented by virtue of engagement of the rearward-facing surfaces 33 of the sheath 14 with the forwardly-facing surfaces 35 of the ramps 26 Further forward movement of the sheath 14 relative to the needle mount is prevented by the engagement of forwardly-facing surfaces 31 of the sheath 14 with rearwardly-facing surfaces 34 of the needle mount 10

In the orientation shown in FIG 2D, the sheath 14 cannot rotate relative to needle mount 10 by virtue of the engagement of radially-extending projections 37 with slots or recesses 29 It will be noted that the rearward end of projections 37 are tapered to facilitate engagement of projections 37 with slots or recesses 29 during forward movement of the sheath 14 In summary, once the sheath reaches the post-use, needle-protected position shown in FIG 2D, it cannot move forwardly, nor backwardly, nor can it be rotated This ensures that the needle cannot be accidentally or deliberately re-exposed

FIGS 3A-3D and 4A-4D are section views of FIGS 2A-2D and show further detail of the invention

In use, the needle assembly is provided to the user in sterile packaging and in the configuration shown in FIG 2A The user removes the packaging and mounts the needle assembly on the forward end of a conventional syringe Typically, mounting of the needle assembly on the conventional syringe involves pushing and twisting the syringe and needle assembly together In cases where the syringe is pre-filled and sealed, the mounting action also has the effect of puncturing the forward end of the barrel of the syringe such that the interior of the syringe is then in fluid communication with the needle Whilst it is desirable that the needle assembly be held by the needle mount 10 during the mounting operation, in circumstances where the needle assembly is held by the sheath 14 the presence of recesses 29 and projections 38, together with the convex ramps 39 ensures that twisting and pushing forces applied to the sheath 14 are effective in mounting the needle assembly on the conventional syringe and do not result in inadvertent movement of the sheath 14 to the orientation illustrated in FIG 2B

Once the needle assembly is mounted on the syringe, the sheath may be moved rearwardly to the configuration shown in FIG 2B The injection can then be made

After the injection is completed, the sheath is rotated by 90 degrees to the configuration shown in FIG 2C As discussed above, rotation of the sheath is releasably resisted such that accidental rotation should not occur Upon reaching the position shown in FIG 2C, the sheath is free to move forward under the influence of the compression spring to the final locked position shown in FIG 2D.

Upon reaching the configuration shown in FIG 2D₁ the sheath is locked and cannot move forwardly, or rearwardly, and nor can it be rotated by virtue of the engagement of recesses 29 with projections 37. This ensures that the needle is no longer a risk of needle-stick injuries, nor can it be re-used either accidentally or deliberately.

The needle assembly can then be dismounted from the forward end of the syringe and disposed of in a sharps container or the like.

Whilst the first embodiment of the invention has been described with reference to an example in which the projections are provided on the needle mount and the recesses are provided on the sheath, a person of skill in the art would appreciate that these can be reversed.

Whilst the first embodiment of the invention has been described with reference to an example in which the projections and recesses are provided in pairs, a person of skill in the art would appreciate that this number could be varied.

Whilst the first embodiment of the invention has been described with reference to an example in which projections are provided at the forward end of both the first pair of opposed sides and the second pair of opposed sides, projections could be provided at the forward end of only one of the pairs of sides, although this would remove some of the benefits of the preferred embodiment. Turning now to the second embodiment illustrated in FIGS 5 to 8, the same reference numerals have been used to denote the same features wherever possible

The elongate needle mount 10 continues to include a rearward frusto-conical portion 16 which terminates in a flange 17 The frusto-conical portion 16 is adapted to receive the forward end of a conventional syringe Forward of the frusto-conical portion 16 is circular-cross-section portion 18, and forward of the circular-cross-section portion 18 is a further circular-cross-section portion of slightly greater diameter This greater- diameter portion includes a first pair of opposed axial slots 50 and a second pair of opposed axial slots 56 The first and second pairs of opposed axial slots 50, 56 correspond to the opposed sides of the previous rectangular-cross-section embodiment

The first pair of opposed axial slots 50 include rearwardly inclined ramps 52 at the rearward end thereof, and further rearwardly inclined ramps 54 at a forward end thereof

The second pair of opposed axial slots 56 include forwardly inclined ramps 58 at the forward end thereof Further forward of forwardly inclined ramps 58 are recesses 62

With brief reference to FIG 6, the sheath 14 continues to be bifurcated in shape and includes opposed tabs 28 However, rather than having recesses in the sheath as in the previous embodiment, the bifurcated sheath 14 now includes inwardly-directed projections 60 which at various times engage the first slots 50, rearwardly inclined ramps 52, 54 second slots 56, forwardly inclined ramps 58, and recesses 62 as will now be described

It will be noted that the first pair of opposed axial slots 50 extend forwardly of the further rearwardly inclined ramp 54 These extensions facilitate assembly of the invention as follows After the compression spring 15 is located within the elongate needle mount, the sheath 14 is pressed onto the front end of the elongate needle mount 10 with the projections 60 aligned with the first pair of opposed axial slots 50 As the sheath 14 is pressed onto the needle mount 10, the projections 60 engage the forward extensions of the first pair of opposed axial slots 50, and the bifurcated sheath 14 thereafter resiliency deforms as the projections 60 pass over the further rearwardly inclined ramps 54 Once the projections have passed over the ramps 54, the projections snap inwardly and the invention is fully assembled and ready for either packaging or immediate use

The user will typically receive the needle assembly of the present invention in sterile packaging After removing the packaging, the needle assembly is mounted on the forward end of a conventional syringe In the event that the syringe is pre-filled with medicament, the mounting of the needle assembly on the syringe may also advantageously result in the rear end of the needle piercing the forward end of the pre- filled syringe such that the needle is in immediate fluid communication with the syringe

During use, the sheath is moved rearwardly in response to the user applying manual force to the tabs 28 As the sheath 14 travels rearwardly, the projections traverse the length of the first pair of opposed axial slots 50 and as the sheath reaches the rearward position, the projections are again urged apart as the projections 60 travel over the rearwardly inclined ramps 52 After passing over ramps 52, the projections snap inwardly and the sheath is retained in the rearward position In the event that the syringe is not of the pre-filled variety, then the medicament can be aspirated into the syringe at this point in time The injection can then proceed

After the injection is made, the sheath is rotated through 90 degrees relative to the needle mount 10 and the projections 60 travel circumferentiaily around the circular- cross-section portion 18 until the projections align with the second pair of opposed axial slots. Once aligned, the sheath springs forward under the influence of the compression spring 15. As the sheath reaches the forward position, the projections pass over forwardly inclined ramps 58. After passing over ramps 58, the projections 60 snap inwardly and engage recesses 62. Once the projections are engaged in recesses 62, the sheath 14 cannot move forwardly or rearwardly, nor can it be rotated relative to the needle mount 10.

It will of course be realised that whilst the above has been given by way of an illustrative example of this invention, all such and other modifications and variations hereto, as would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of this invention as is herein set forth.

Claims

The claims defining the invention are as follows:-

1 An improved needle assembly including - an elongate needle mount having a forward end and a rearward end spaced along an axis, and having first and second pairs of opposed sides extending parallel to said axis, a needle extending axially from the forward end of the elongate needle mount, a sheath mounted on the elongate needle mount for reciprocal axial movement between a forward position whereat the sheath covers the needle and a rearward position whereat the needle is exposed, the sheath including opposed resilient members which are adapted to engage a pair of the opposed sides of the elongate needle mount, and characterised in that - at least one of said pair of opposed resilient members includes one of a projection thereon or a recess therein, and at least one of said first pair or said second pair of opposed sides of the needle mount includes the other of a projection thereon or a recess therein at a forward end thereof, said recess and projection cooperating to prevent rotation of the sheath relative to the needle mount about the axis when said recess and projection are engaged in a forward position

2 An improved needle assembly as claimed in claim 1 , wherein the elongate needle mount includes a rectangular cross-section portion which defines the first and second pairs of opposed sides

3 An improved needle assembly as claimed in claim 1 , wherein a projection is at the forward end of at least one of said first pair of opposed sides of the needle mount and the projection cooperates with a recess in at least one of the opposed resilient members to prevent rotation of the sheath relative to the needle mount prior to use

4 An improved needle assembly as claimed in claim 3, wherein a rearwardly inclined ramp is disposed proximate the projection to releasably resist rearward movement of the sheath relative to the needle mount prior to use

5 An improved needle assembly as claimed in claim 3, wherein a projection is at the forward end of both of said first pair of opposed sides of the needle mount, and wherein recesses are provided in both of the opposed resilient members

6 An improved needle assembly as claimed in claim 1 , wherein a projection is at the forward end of at least one of said second pair of opposed sides of the needle mount and the projection cooperates with a recess in at least one of the opposed resilient members to prevent rotation of the sheath relative to the needle mount about the axis after use

7 An improved needle assembly as claimed in claim 6, wherein an abutment is disposed proximate the projection such that the sheath cannot be moved rearwardly relative to the needle mount after use

8 An improved needle assembly as claimed in claim 6, wherein the projection is rearwardly tapered to facilitate engagement of the projection with the recess

9 An improved needle assembly as claimed in claim 6, wherein a projection is at the forward end of both of said second pair of opposed sides of the needle mount, and wherein recesses are provided in both of the opposed resilient members

10. An improved needle assembly as claimed in claim 1 , wherein a projection is at the forward end of at least one of said first pair of opposed sides of the needle mount, and another projection is at the forward end of at least one of the second pair of opposed sides of the needle mount, and a recess is provided in at least one of the opposed resilient members.

1 1 . An improved needle assembly as claimed in claim 10, wherein a projection is at the forward end of both of said first pair of opposed sides of the needle mount and at the forward end of both of said second pair of opposed sides of the needle mount, and wherein recesses are provided in both of the opposed resilient members,

12. An improved needle assembly as claimed in claim 1 , wherein the elongate needle mount is generally rectangular in cross-section such that the first pair of opposed sides are more spaced apart than the second pair of opposed sides.

13. An improved needle assembly as claimed in claim 1 , wherein the rearward end of at least one of said first pair of opposed sides includes a detent which cooperates with a recess provided in at least one of the opposed resilient members for releasably resisting rotation of the sheath relative to the elongate needle mount about the axis.

14. An improved needle assembly as claimed in claim 13, wherein the rearward ends of both of the first pair of opposed sides includes a detent which co-operates with a recess provided in each of the opposed resilient members for releasably resisting rotation of the sheath relative to the elongate needle mount about the axis. 15 An improved needle assembly as claimed in claim 1 , wherein the elongate needle mount is circular in cross-section, and wherein said first and second pairs of opposed sides are defined by first and second pairs of opposed axial slots formed in the elongate needle mount, and wherein said pair of opposed resilient members each include projections adapted to engage the first or second pair of opposed slots

16 An improved needle assembly as claimed in claim 15, wherein a forwardly inclined ramp is disposed at the forward end of each of the second pair of opposed axial slots

17 An improved needle assembly as claimed in claim 16, wherein said recess is located forwardly of the forwardly inclined ramp

18 An improved needle assembly as claimed in claim 15, wherein a rearwardly inclined ramp is disposed at the rearward end of each of the first pair of opposed axial slots

19 An improved needle assembly as claimed in claim 18, wherein a circular cross section portion of the needle mount is provided rearwardly of the rearwardly inclined ramps such that the sheath can rotated relative to the needle mount such that the projections become aligned with the second pair of opposed axial slots

20 An improved needle assembly as claimed in claim 18, wherein a further rearwardly inclined ramp is disposed at the forward end of each of the first pair of opposed axial slots 21. An improved needle assembly as claimed in claim 20, wherein the first pair of opposed axial slots extend forwardly of the further rearwardly inclined ramp to facilitate mounting of the sheath on the elongate needle mount.