WO1997039786A1

WO1997039786A1 - A safety hypodermic needle

Info

Publication number: WO1997039786A1
Application number: PCT/AU1997/000239
Authority: WO
Inventors: Luigi Luke Pisaniello; Marcel Paul Stephan
Original assignee: Luigi Luke Pisaniello; Marcel Paul Stephan
Priority date: 1996-04-22
Filing date: 1997-04-17
Publication date: 1997-10-30
Also published as: AUPN941296A0

Abstract

A safety hypodermic needle which has a blunt inner tube and a sharp outer tube (7) slideable on the inner tube (2) and a retention means (10) between a boss (1) on the inner tube (2) and the outer tube (7). The retention means (10) in a rest position retains the outer tube (7) in a safety position and in an activated position extends the outer tube so that the hypodermic needle can be used to puncture the skin of a patient. The retention means can be resilient. The system can also be used with vacuum blood withdrawal systems.

Description

TITLE A SAFETY HYPODERMIC NEEDLE

TECHNICAL FIELD

This invention relates to a hypodermic needle suitable for either human or veterinary use.

BACKGROUND ART

A serious problem exists with what are termed needle stick injuries relating to the use of hypodermic needles. A hypodermic needle is necessarily sharpened so that it may be pushed through the skin but once used it is desirable that the hypodermic needle can not cause injury. Many previous proposals have been made for systems whereby the needle of a hypodermic syringe is rendered safe after use but most of these systems have been complicated and require a specific operator function to render them safe.

The object of this invention is to provide a needle for a hypodermic syringe which is essentially fail safe.

DISCLOSURE OF THE INVENTION

In one form therefore, the invention is said to reside in a safety hypodermic needle compπsing a boss, an inner tube extending from the boss, the inner tube having a blunt end remote from the boss, an outer tube concentric with and slidably engaged onto the inner tube, the outer tube having a boss end and a remote end, the remote end being sharpened so as to enable it to puncture the skin of a patient in use, and a retention means between the boss of the inner tube and the boss end of the outer tube, the retention means adapted in its rest position to retain the outer tube in a position such that the blunt end of the inner tube extends beyond the sharpened remote end of the outer tube, the retention means being able to be activated such that in an activated position the remote end of the outer tube extends beyond the blunt end of the inner tube such that the hypodermic needle can be used to puncture the skin of a patient.

It will be seen that by this means there is provided an arrangement where the hypodermic needle is of a fail safe construction because in its rest position the blunt end of the inner tube extends beyond the sharpened end of the outer tube and even when the sharp end extends beyond the inner tube pressure on the needle which is not specifically resisted will push the outer tube back behind the blunt end making the needle essentially safe.

In a preferred embodiment the retention means comprises a resilient means between the boss of the inner tube and the boss end of the outer tube, the resilient means adapted in its rest position to retract the outer tube into a position such that the blunt end of the inner tube extends beyond the sharpened remote end of the outer tube, the resilient means being able to be activated such that in an activated position the remote end of the outer tube extends beyond the blunt end of the inner tube such that the hypodermic needle can be used to puncture the skin of a patient.

The resilient means may comprise at least one arcuate band connected at one end to the boss of the inner tube and at the other end to the boss end of the outer tube and wherein the activation of the resilient means is achieved by flattening out of the arcuate band.

The arcuate band, the boss of the inner tube and the boss end of the outer tube may be integrally moulded.

There may be a plurality of resilient arcuate bands which form a cage between the boss of the inner tube and the boss end of the outer tube.

Alternatively the resilient means may comprise at least one helical shaped band connected at one end thereof to the boss of the inner tube and at the other end to the boss end of the outer tube.

Alternatively the resilient means comprises an extension spring connected at one end to the boss of the inner tube and at the other end to the boss end of the outer tube.

The outer diameter of the inner tube may be substantially the same as the inner diameter of the outer tube such that the outer tube is a close fit on the inner tube.

In a preferred embodiment there may be further including a finger engagement means on the boss end of the outer tube such that finger pressure in use onto the finger engagement means can extend the outer tube to the use position. There may also be including a groove in the boss into which may be resiliently retained a detent on the finger engagement means when the outer tube is in the activated position.

The boss of the inner tube may include a tapered connection of the Luer lock type or a screw type connection for connection of the needle to a hypodermic syringe.

The safety hypodermic needle of the present invention may be adapted to be used with a vacuum blood withdrawal arrangement, the boss having a first screw thread thereon adapted to be received into a corresponding screw thread in a needle holder and a vacuum tube piercing needle extending from the boss in a direction diametrically opposite to that of the inner tube.

In this embodiment the retention means between the boss of the inner tube and the boss end of the outer tube comprises an arcuate band extending from the needle holder and a second screw threaded portion on the band co-axial with the first screw threaded portion on the needle holder and adapted upon insertion of the needle into the needle holder to engage with a corresponding screw threaded portion on the boss end of the outer tube, the arcuate band being able to be activated to move the outer tube over the inner tube from a needle protected position to a needle extended position.

Generally it will be seen that by this invention with the outer tube being the sharpened tube and being able to slide along the inner tube it can retract over the inner tube so that the sharpened end does not provide a danger to users or patients. When it is desired to use the needle then simple finger pressure can push the outer tube far enough forward either against the resilient means or the retention means to enable the needle to pierce the skin.

BRIEF DESCRIPTION OF THE DRAWINGS

This generally describes the invention but t. assist with understanding of the invention reference will now be made to the accompanying drawings in which:

FIG 1 shows a cross-sectional view of one embodiment of safety hypodermic needle according to this invention;

FIG 2 shows the embodiment of Figure 1 in the extended position;

FIG 3 shows a side view of the embodiment of Figure 1 ;

FIG 4 shows a side view of the embodiment of Figure 2;

FIG 5 shows an alternative embodiment of safety hypodermic needle with a cage of resilient bands;

FIG 6 shows the embodiment as shown in Figure 5 with the needle extended;

FIG 7 shows an alternative embodiment of hypodermic needle according to this invention with a non-resilient retention means between the fixed and moving parts of the needle;

FIG 8 shows the embodiment of Figure 7 with the moving part in the extended position;

FIG 9 shows a cross-sectional view of the embodiment shown in Figure 7;

FIG 10 shows a further embodiment of the invention using an extension spring as the resilient means;

FIG 11 shows the embodiment of Figure 10 in the extended position;

FIG 12 A and B show an alternative embodiment of hypodermic needle according to this invention with separate parts for the fixed tube and moving needle which can be assembled together;

FIG 13 shows a perspective view of the alternative embodiment of hypodermic needle according to this invention of FIG 12;

FIG 14 shows the embodiment of Figure 12 with the moving part in the extended position; and FIGS 15A, B, C and D show various stages in the assembly and use of an alternative embodiment of a safety hypodermic needle of the present invention which is particularly adapted for the extraction of a patient's blood using a vacuum tube system.

BEST MODE FOR CARRYING OUT THE INVENTION

Now looking more closely at the drawings and in particular the embodiment shown in FIGS 1 to 4 it will be seen that the safety hypodermic needle according to this embodiment invention comprises a boss section 1 with a elongate inner tube 2 which terminates in a blunt end 3. The boss includes a gripping shoulder 4 and a Luer lock taper arrangement for connecting on to the tube of a hypodermic syringe (not shown). An outer tube 7 has a boss end 8 and a sharpened remote end 9. It will be noted that in the embodiment shown in FIG 1 the sharpened remote end is withdrawn over the blunt end so that it can not injure someone.

Between the boss 1 and the boss end 8 of the outer tube two resilient bands

10 extend.

When pressure is directly applied on the resilient bands 10 to flatten them out or the boss end 8 of the outer tube is slid forward the arrangement as shown in FIG 2 occurs. Here the sharpened remote end 9 extends beyond the blunt end 3 so that the needle may be inserted through the skin of a patient. Once inserted the sharpened end 9 may be again retracted beyond the blunt end for injection purposes which occurs through the inner tube.

In an alternative embodiment of the invention as shown in FIGS 5 and 6 there is a cage of resilient bands 20 extending between the boss 21 and the boss end 22 of the outer tube 23. The resilient bands 20 are formed in such a way that in there rest position the sharpened end 24 of the outer tube is retracted to expose the blunt end 25 of the inner tube 26.

In this embodiment the cage 20 may have direct pressure placed upon it to move the outer tube forward to the insertion position.

In the embodiment shown in FIGS 7, 8 and 9 the retention means generally shown as 30 comprise a plurality of rods 31 extending from a shoulder 32 on the boss 33 of the outer tube 34. The inner tube 35 has a boss 36 which includes a flange 37 which has apertures through which the rods 31 pass. The rods have enlargements 38 at their terminal ends so that they cannot be pulled through the apertures 39 in the flange 37 to enable the outer tube to come off the inner tube.

The embodiment shown in FIGS 10 and 11 has an extension spring 40 between the boss 41 of the inner tube 42 and the boss 43 of the outer tube 44. A finger engagement shoulder 46 enables a finger to push the boss 43 and the outer tube 44 forward so that the sharpened part 45 extends beyond the blunt end of the inner tube 42 to enable the needle to pierce the skin. When pressure is removed from the shoulder 46 the sharpened outer tube will retract so that again the blunt end of the inner tube 42 is exposed and the needle is in a fail safe position.

FIGS 12A and B, 13 and 14 show an embodiment of the invention in which the resilient retaining means is a helical shaped band resilient 50 which is at one end connected to a finger engagement extension 51 of the which is mounted to the boss 52 on the moveable sharpened needle 53. At the other end of the helical shaped band 50 is a moulded ring 54 which when the two parts shown in FIGS 12A and B are assembled fits into a groove 55 in the boss 56 of the fixed blunt tube 57. The boss 56 also includes a pair of shoulders 58 which act as guides for the finger engagement extension 51 as it is moved forward so as to move the sharpened needle 53 over the blunted tube 57. The finger engagement extension also includes a detent 58A on its underside which when the finger engagement extension is in the extended position is received into a groove 59 in the boss 52 so that transverse pressure on the finger engagement extension assists with retaining the sharpened needle in the forward position. Removal of finger pressure on the finger engagement extension 51 causes the detent 58A to come out of the groove 59 and then the helical shaped resilient band tracts the sharpened needle to expose the blunted tube and render the needle safe.

The aperture 60 is of a standard LUER taper so as to receive the spout of a syringe.

FIGS 15A, B, C and D show various stages in the assembly and use of an alternative embodiment of a safety hypodermic needle of the present invention which is particularly adapted for the extraction of a patient's blood using a vacuum tube.

The assembly consists of a reusable needle holder 61 , a disposable needle assembly 62 of the present invention and a vacuum tube 63 of known construction.

The reusable needle holder 61 has a body 65 of generally cylindrical shape and an end wall 66 at one end in the centre of which is a first threaded aperture 67 aligned with the longitudinal axis of the cylindrical body 65. Extending from one side of the end wall 66 is a resilient band 68. On the end of the band 68 is an enlargement 69 which has a second threaded aperture 70 which is co-axial with the first threaded aperture 67 and the cylindrical body 65.

The disposable needle assembly 62 comprises an inner boss 71 approximately in the centre of an elongate tube 73 of which the end 74 is sharpened and the end 75 is blunt. The inner boss 71 has a male thread 76 corresponding to the thread of the first threaded aperture 67. Over the elongate tube and on the blunt end side of the boss 71 is a needle 77 with an outer boss 78. The outer boss 78 has a male thread 79 corresponding to the thread of the second threaded aperture 70. The sizes of the threaded portions are such that the threaded boss 71 will pass through the threaded aperture 70 without engaging that thread.

Extensions 84 on the inner boss 71 extend parallel to the tube 73 towards the outer boss 78 and are received in slots 85 in the outer boss 78 so that at least in the retracted position of the sharpened needle rotation of one of the bosses also rotates the other boss.

A cap 81 fits over the needle 77 and engages onto a taper 82 on the boss 78.

The process of use of the vacuum blood extraction needle according to this embodiment of the invention is as follows.

The needle assembly 62 is inserted into the needle holder 61 so that the first and second threads mate into their respective threaded apertures so that the needle assembly is retained in the needle holder as shown in FIG 15B. To enable the insertion of the needle into a patient the resilient band 68 is depressed or the enlargement 69 is pushed forward so that the needle 77 is propelled forward to extend beyond the blunt end 75. Once the needle is inside a patient the band 68 or the enlargement 69 is released and the sharpened needle retracts. A vacuum tube 63 is then inserted into the needle holder as shown in FIG 15D. The needle 74 pierces the seal 86 and the vacuum within the tube 63 withdraws blood through the tube 73.

It will be seen that by this invention there is provided a safety system where except when the needle is to be used for piercing the skin only a blunt end of the hypodermic needle is exposed and therefore the needle is much less likely to cause needle stick injuries.

It will be realised that the hypodermic needle according to this invention may be placed onto existing syringes. The inner and outer tubes may as conventionally be made from stainless steel and the bosses of each of the tubes may be from injection moulded plastic or the like. Alternatively at least the inner tube may be manufactured from plastics material.

Throughout this specification and the claims that follow unless the context requires otherwise, the words 'comprise' and 'include' and variations such as 'comprising' and 'including' will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

1. A safety hypodermic needle comprising a boss, an inner tube extending from the boss, the inner tube having a blunt end remote from the boss, an outer tube concentric with and slidably engaged onto the inner tube, the outer tube having a boss end and a remote end, the remote end being sharpened so as to enable it to puncture the skin of a patient in use, and a retention means between the boss of the inner tube and the boss end of the outer tube, the retention means adapted in its rest position to retain the outer tube in a position such that the blunt end of the inner tube extends beyond the sharpened remote end of the outer tube, the retention means being able to be activated such that in an activated position the remote end of the outer tube extends beyond the blunt end of the inner tube such that the hypodermic needle can be used to puncture the skin of a patient.

2. A safety hypodermic needle as in Claim 1 wherein the retention means comprises a resilient means between the boss of the inner tube and the boss end of the outer tube, the resilient means adapted in its rest position to retract the outer tube into a position such that the blunt end of the inner tube extends beyond the sharpened remote end of the outer tube, the resilient means being able to be activated such that in an activated position the remote end of the outer tube extends beyond the blunt end of the inner tube such that the hypodermic needle can be used to puncture the skin of a patient.

3. A safety hypodermic needle as in Claim 2 wherein the resilient means comprises at least one arcuate band connected at one end to the boss of the inner tube and at the other end to the boss end of the outer tube and wherein the activation of the resilient means is achieved by flattening out of the arcuate band.

4. A safety hypodermic needle as in Claim 3 wherein the arcuate band, the boss of the inner tube and the boss end of the outer tube are integrally moulded.

5. A safety hypodermic needle as in Claim 3 wherein there is a plurality of resilient arcuate bands which form a cage between the boss of the inner tube and the boss end of the outer tube.

6. A safety hypodermic needle as in Claim 2 wherein the resilient means comprises at least one helical shaped band connected at one end thereof to the boss of the inner tube and at the other end to the boss end of the outer tube.

7. A safety hypodermic needle as in Claim 2 wherein the resilient means comprises an extension spring connected at one end to the boss of the inner tube and at the other end to the boss end of the outer tube.

8. A safety hypodermic needle as in Claim 1 wherein an outer diameter of the inner tube is substantially the same as the inner diameter of the outer tube such that the outer tube is a close fit on the inner tube.

9. A safety hypodermic needle as in claim 1 further including a finger engagement means on the boss end of the outer tube such that finger pressure in use onto the finger engagement means can extend the outer tube to the use position.

10. A safety hypodermic needle as in claim 9 further including a groove in the boss into which may be resiliently retained a detent on the finger engagement means when the outer tube is in the activated position.

11. A safety hypodermic needle as in any one preceding claim wherein the boss of the inner tube includes a tapered connection of the Luer lock type or a screw type connection for connection of the needle to a hypodermic syringe.

12. A safety hypodermic needle as in any one preceding claim adapted to be used with a vacuum blood withdrawal arrangement, the boss having a first screw thread thereon adapted to be received into a corresponding screw thread in a needle holder and a vacuum tube piercing needle extending from the boss in a direction diametrically opposite to that of the inner tube.

13. A safety hypodermic needle as in Claim 12 wherein the retention means between the boss of the inner tube and the boss end of the outer tube comprises an arcuate band extending from the needle holder and a second screw threaded portion on the band co-axial with the first screw threaded portion on the needle holder and adapted upon insertion of the needle into the needle holder to engage with a corresponding screw threaded portion on the boss end of the outer tube, the arcuate band being able to be activated to move the outer tube over the inner tube from a needle protected position to a needle extended position.