WO2007121505A1

WO2007121505A1 - A needle assembly

Info

Publication number: WO2007121505A1
Application number: PCT/AU2007/000473
Authority: WO
Inventors: Geoffrey Daniel Daly; Paul Joseph Fabre
Original assignee: Analytica Limited
Priority date: 2006-04-24
Filing date: 2007-04-24
Publication date: 2007-11-01

Abstract

A needle assembly (10) to be mounted on the forward end of a hypodermic syringe (11). The assembly (10) includes a needle (51) that is to be covered by a cover (58). The cover (58) is movable between a retracted position exposing the needle (51), and an extended position covering the needle (51). The cover (58) is urged to the extended position by a spring (75). A catch member (68) is operable to release the cover (58) for movement to the extended position.

Description

A NEEDLE ASSEMBLY

Technical Field

The present invention relates to needle assemblies for hypodermic syringes and more particularly to needle assemblies for a hypodermic syringe to reduce the occurrence of needlestick injuries.

Background of the Invention

The safe disposable of sharp medical instruments is of a prime concern to healthcare professionals such as doctors and nurses. For example, a particular problem is the safe disposal of needles (hypodermic syringes). An accidental puncture can result in the healthcare professional becoming infected with a serious disease such as Acquired Immune Deficiency Syndrome and Hepatitis.

A wide variety of methods are proposed to inhibit accidental needlestick injuries, with such methods including withdrawing the needle to the interior of the syringe after use. An example of such a method is disclosed in International Application PCT/AU2204/001793 (WO 2005/058399).

The devices involved in the above discussed methods have a number of disadvantages including the devices being relatively intricate and relatively expensive to manufacture.

Most of the needles and syringes designed to prevent needlestick injuries have the problem that the syringe plunger cannot be fully depressed (zero syringe volume) without activating the mechanism. This is not usually a problem with drug delivery, where zero- volume occurs in the syringe after it has done it's job. It is a problem with the extraction of venous blood though, where the zero volume condition in the syringe is required prior to use to prevent air bubbles being accidentally inserted into the patient. Given that the zero- volume condition is the usual trigger for most 'automatic' safety needles and syringes, they are not suitable for blood sample collection.

Another problem with safety needle designs is the motion of the needle into a protected cavity on activation. The volume required for this displacement of the needle (and associated components) adds to the amount of fluid retained in the device on disposal. This may mean excess blood is taken from a patient, or excess expensive medicine is required in addition to that delivered to the patient. The large volume of fluid inside the device and the relative movement of the needle and other 'wet' parts adds to the risk of blood or other infectious fluid being ejected from the device on activation, or leaking from the device before disposal.

Object of the Invention It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages.

Summary of the Invention

There is disclosed herein a needle assembly for a hypodermic syringe having a hollow body within which there is located a plunger, the body having a forward end, to receive the needle assembly, and a rear end through which the plunger projects to enable a user to move the plunger relative to the body, said assembly including: a needle having a longitudinal axis; a base supporting the needle and to be mounted at said forward end so that the needle projects forwardly therefrom; a needle tip cover mounted on the base for relative movement with respect to the needle between a retracted position at which a length of the needle, including the tip, is exposed, and an extended position covering at least the needle tip; a biasing part urging the cover to the extended position thereof; and a catch device retaining the cover in the retracted position but operable by a user to release the cover for movement to the extended position.

Preferably, the biasing part is a spring.

Preferably, the catch device is a catch member mounted on the base for pivoting movement about an axis generally transverse of said axis so as to be pivotable to release the catch member. In an alternative preferred form, said catch device is a catch member slidably mounted on said base for transverse movement relative to said axis and to release the catch member.

Preferably, said base includes a mounting portion to engage said forward end, and a housing portion within which said cover is located when in the retracted position. Preferably, said cover is slidably mounted in the base for linear movement between the retracted and extended positions thereof.

Preferably, the assembly includes a lock member that engages the cover to retain the cover in the extended position. Preferably, said base includes a stop that is engaged by the cover when located in the extended position.

Preferably, the assembly includes a cap covering the needle when the tip is exposed, the cap being operatively associated with the catch member to retain the catch member in a position retaining the cover in a retracted position, with removal of the cap thereby permitting operation of the catch member for movement to release the cover.

Preferably, the cap covers said tip.

Preferably, said cover has at least one radially outwardly extending projection that is engaged by the catch member to retain the cover in the retracted position.

Brief Description of the Drawings

A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings wherein:

Figure 1 is a schematic isometric view of a needle assembly mounted on the forward end of a hypodermic syringe; Figure 2 is a schematic sectioned side elevation of the assembly of Figure 1 in an unactivated configuration;

Figure 3 is a further schematic sectioned side elevation of the assembly of Figure 1 in an activated configuration;

Figure 4 is a schematic isometric view of a further needle assembly; Figure 5 is a schematic longitudinally sectioned isometric view of the assembly of

Figure 4 in an unactivated configuration;

Figures 6 to 8 are schematic sectioned side elevations of the assembly of Figure 4;

Figure 9 is a schematic sectioned side elevation of the assembly of Figure 4 in an activated configuration; Figure 10 is a schematic isometric view of portion of the assembly of Figure 4; and

Figure 11 is a schematic isometric view of a needle cover employed in the assembly of Figure 4.

Detailed Description of the Preferred Embodiments In Figures 1 to 3 of the accompanying drawings there is schematically depicted a needle assembly 10 to be mounted on a hypodermic syringe 11. The syringe 11 has a cylindrical hollow body 13 with a forward end 12 upon which the assembly 10 is mounted. The body 13 is hollow and slidably receives a plunger (piston) 14 that projects outwardly of the rear of the body 13 and is engaged by a user to cause longitudinal movement of the piston 14 to draw liquid in and to expel liquid from the syringe 11 via the assembly 10. The body 13 has a longitudinal axis 15 that is also the longitudinal axis of the needle 16.

The assembly 10 includes the needle 16 as well as a needle base 17 to which the needle 16 is fixed. The base 17 includes a socket 18 (preferably a female luer-lock fitting) that engages the forward end 12 of the body 13 so as to be securely engaged therewith. The end 12 will usually be a luer-slip fitting or a luer lock male fitting. Extending forwardly from the socket 18 is a housing 19. A transverse wall 20 joins the socket 18 with the housing 19. The wall 20 has a central passage 21 in which the needle 16 is located and via which the needle 16 is fixed to the base 17. The needle 16 projects from the wall 20 so as to be located internally of the forward end 12 of the body 13 so that liquid located on the interior of the syringe 11 can be forced out through the needle 16 by operation of the plunger 14.

The housing 19 surrounds a portion of the needle 16 and provides a cavity 22 within which there is located a needle tip cover 23. The cover 23 is movable from a retracted position located at least substantially within the cavity 22 (Figure 2) and an extended position covering at least the needle tip 24, and more preferably covering the entire length of the needle 16 that is exposed when the cover 23 is in the retracted position. Accordingly the cover 23 is movable slidably movable longitudinally of the needle 16 along a linear path. The cover 23 moves through a central aperture 25 in the forward end of the housing 19.

A spring 26 is located internally of the housing 19 and surrounds the needle 16 and is compressed between the wall 20 and a flanged end 27 of the cover 23. Accordingly the spring 26 urges (biases) the cover 23 to move from the retracted position as shown in Figure 2 to the extended position as shown in Figure 3.

A catch member 28 is pivotally mounted on the body 13 for pivoting movement about a transverse axis 29 between a retaining position (as shown in Figure 2) retaining the cover 23 in the retracted position, and a release position permitting movement of the cover 23 to the extended position. More particularly the member 28 has an end portion 30 that is engaged by a finger or thumb of the user to cause movement of the portion 30 in the direction of the arrow 31 to thereby move the catch end 32 of the member 28 from the position shown in Figure 2 to the position shown in Figure 3 thereby releasing the cover 23. More particularly the catch end 23 projects across the end 33 of the cover 23 to retain it in the retracted position. When the cover 23 is in the extended position the tip 24 is covered thereby reducing the risk of a needlestick injury.

In Figures 4 to 11 there is schematically depicted a modification of the assembly

10. In this embodiment the assembly 50 has a needle 51 fixed to the transverse wall 52 of the base 53 by means of an insert 75. The needle 51 terminates internally of the wall 52 but communicates with the cavity 54 of the socket 55. Again the socket 55 is configured to securely engage the forward end 12 of the syringe 11.

The base 53 also includes a housing 56 that provides a cavity 57 within which the cover 58 is located. The housing 56 includes one or more resilient lock members 59 that are urged radially inwardly relative to the axis 60 so as to engage the rear of the cover 58 when the cover 58 is in the extended position. This is best seen in Figure 9, where the forward end of each lock member 59 is illustrated as located behind the rear 61 of the cover 58, therefore retaining the cover 58 in the extended position covering the needle tip 62. Extending between the forward end of the cover 58, and a projection 63 is a spring 75, urging the cover 58 to the extended position, that is the position covering the tip 62. In that respect it should be appreciated the cover 58 has a central aperture 64 through which the needle passes when the cover 58 is retracted. The cover 58 generally surrounds the needle 51 and moves longitudinally relative thereto between the extended and retracted positions of the cover 58.

Preferably the housing 56 has longitudinally extending grooves 65 within which radial projections 71 of the cover 58 are slidably located so as to be movable longitudinally thereof. Preferably the cover 58 has a longitudinally extending depression 67 within which the member 59 is located when the cover 58 is retracted. Slidably mounted on the base 53 is a catch member 68 that is movable in a direction 69 that is generally normal (transverse) of the longitudinal axis 60. The catch member 68 is of a "loop" configuration so as to generally surround the base 53 adjacent the wall 52, and is engaged by guide projections 70 so as to be movable in the direction 69, that is a linear path generally perpendicular to the axis 60. The catch member 68, when retaining the cover 58 in the retracted position, engages one or more of the radial projections 71 at the rear of the cover 58, while when sufficiently displaced in the direction 69 the catch member 68 clears the projection 71 and permits the cover 58 to move to the extended position. More particularly the catch member 68 has a lip 72 to engage an associated one of the projections 71, when the cover 58 is in the retracted position.

It should be appreciated the abutting surfaces of the member 68 and lip 67 are inclined to inhibit the catch member 68 being urged to the release position by action of the spring 64 on the cover 58. More particularly (as best seen in Figure 8) the abutting surfaces of the projection 71 and lip 72 are inclined by an acute angle to the longitudinal axis 60 so that the spring 75 urges the projections 71 to actually urge the member 68 to the retaining position. When the catch member 68 is moved in the direction of the arrow 69, the lip 72 is moved from engagement with the associated projection 71. Accordingly under the influence of the spring 64, the cover 58 moves to the extended position covering the tip 62 and therefore reducing the risk of a needlestick injury. The projections 71 also engage the end 72 of the base 53 when the cover 58 is in the extended position. The projections 71 slide longitudinally of the grooves 65.

The cover 58 also has longitudinally extending slots 76 providing arms 77 (having the projection 71). The arms 77 are resilient deformable aiding assembly of the assembly 10 by radial inward deflection of the arms 77.

Each lock member 59 is resiliently deflected radially outward as the cover 58 moves to the extended position, and then moves radially inward after the rear 61 moves past the members 59 to thereby retain the cover 58 in the extended position. If so required an outer sheath 73 may be provided enclosing substantially the entire length of the assembly 50 including the tip 62. The sheath 73 also aids use of the assembly 50 when attaching the assembly to a male luer-lock syringe. The sheath 73 also protects the assembly 50 during transportation. The sheath 73 has an annular flange 74 that projects between the catch member 58 and the sheath 73, to prevent accidental actuation of the member 68. The member 68 becomes operable when the sheath 73 is removed.

The majority of the parts of the assembly 10 and assembly 50 are moulded from plastics material (particularly not including the needle 16). In that respect the depression/s 67 provide for location of the lock members 59 (when the assembly 50 is unactivated) to inhibit "creep", thereby prolonging shelf life.

Claims

CLAIMS:

1. A needle assembly for a hypodermic syringe having a hollow body within which there is located a plunger, the body having a forward end, to receive the needle assembly, and a rear end through which the plunger projects to enable a user to 5 move the plunger relative to the body, said assembly including: a needle having a longitudinal axis; a base supporting the needle and to be mounted at said forward end so that the needle projects forwardly therefrom; a needle tip cover mounted on the base for relative movement with respect to the I₀ needle between a retracted position at which a length of the needle, including the tip, is exposed, and an extended position covering at least the needle tip; a biasing part urging the cover to the extended position thereof; and a catch device retaining the cover in the retracted position but operable by a user to release the cover for movement to the extended position. 15

2. The assembly of claim 1, wherein the biasing part is a spring.

3. The assembly of claim 1 or 2, wherein the catch device is a catch member mounted on the base for pivoting movement about an axis generally transverse of said axis so as to be pivotable to release the catch member.

4. The assembly of claim 1 or 2, wherein said catch device is a catch 0 member slidably mounted on said base for transverse movement relative to said axis and to release the catch member.

5. The assembly of anyone of claims 1 to 4, wherein said base includes a mounting portion to engage said forward end, and a housing portion within which said cover is located when in the retracted position. 5

6. The assembly of any one of claims 1 to 5, wherein said cover is slidably mounted in the base for linear movement between the retracted and extended positions thereof.

7. The assembly of any one of claims 1 to 6, wherein the assembly includes a lock member that engages the cover to retain the cover in the extended position. 0

8. The assembly of any one of claims 1 to 7, wherein said base includes a stop that is engaged by the cover when located in the extended position.

9. The assembly of claim 4, wherein the assembly includes a cap covering the needle when the tip is exposed, the cap being operatively associated with the catch member to retain the catch member in a position retaining the cover in a retracted position, with removal of the cap thereby permitting operation of the catch member for movement to release the cover.

10. The assembly of claim 8, wherein the cap covers said tip.

11. The assembly of claim 9, wherein said cover has at least one radially outwardly extending projection that is engaged by the catch member to retain the cover in the retracted position.

12. A needle assembly for a hypodermic syringe, the assembly being substantially as hereinbefore described with reference to Figures 1 to 3 or Figures 4 to 11.