AU780560B2

AU780560B2 - Hypodermic needle protective cover

Info

Publication number: AU780560B2
Application number: AU10072/01A
Authority: AU
Inventors: Dennis F. Burley; Peter D. Burley
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-10-15
Filing date: 2000-10-16
Publication date: 2005-04-07
Anticipated expiration: 2020-10-16
Also published as: AU1007201A

Description

PCT/AUOO/0 1252 Received on 23 January 2002 Title of Invention: Hypodermic Needle Protective cover.

Field of invention: This invention relates to safety devices for medical or veterinary use, In particular, the invention relates to a protective cover for a hypodermic needle and to a method for the manufacture of the cover.

Background of the Invention: In the clinical uses of hypodermic needles there are several hazards and issues of concern regarding public health.

Needle-stick injuries are a major cause of morbidity in health-care workers, refuse handlers and, to a lesser extent the general public. In this context, needle-stick injuries may be defined as the sharp of a needle penetrating or tearing a victim's skin.

In a needle-stick injury there may or may not be an added hazard of contaminated blood or body fluid present in or on the needle that may then be transferred to the victim.

In addition, even if there is no needle-stick injury per se, contarninants on the needle may still be transferred to a victim through an existing open wound or through contact with the mucous membranes (such as by wiping the eye or mouth with acontaminated hand).

A major public health concern with hypodermic needles is the re-use of the needle by multiple users. Such re-use or sharing of needles is believed to be the AMENDED SHEET

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PCT/AU00/01252 Received on 23 January 2002 predominant means of transfer of diseases such as HIV, Hepatitis B, Hepatitis C and similar blood-borne viruses.

Thus, there is a need for a reliable device that can protect the sharp tip of a hypodermic needle after use, contain body fluids after use and prevent or discourage the re-use of the needle.

Advantageously, the device would be robust and impact resistant and ideally would be economical to manufacture and fit to existing designs of needle.

The present invention seeks to satisfy this need.

Summary of the Invention: This invention accordingly provides a protective cover for a hypodermic needle comprising: a flexible, fluid impermeable sheath encasing a needle; biasing means comprising a coil-spring arranged so that the shaft of the needle passes through a lumen formed by the coils and in which the end of the spring that is disposed towards the tip end of the needle is a tightly wound cone of suitable dimensions to enclose and provide protection to the needle tip; and latching means; in which the sheath is compressed against the biasing means down the shaft of the needle thereby exposing the needle ready for use and the sheath is latched into that compressed position by the latching means; and whereas, in use, the needle is inserted into a patient, blood drawn or medication injected, then the latching means is released allowing the sheath to move in response to the biasing means so that, as the needle is withdrawn from the patient, -2- AMENDED SHEET

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PCT/AUOO/0 1252 Received on 23 January 2002 the sheath extends along the needle shaft to a point substantially against the patient's skin and, as the withdrawal of the needle continues, the sheath further extends substantially against the patient's skin until it completely encases the needle and the sheath is re-closed.

The invention also provides a method for the manufacture of a protective cover for a hypodermic needle comprising: providing a dipping mould and a coiled spring, said spring having a tight coilspring cone at its outer end; attaching the spring to the dipping mould; providing a medical grade latex medium of selected appropriate conditions of viscosity and gelling strength; and dipping the mould and attached spring into the latex medium in such a manner that the latex flows under and over the spring thereby forming a tube with the spring embedded in its wall.

Preferred Aspects of the invention: It is Preferred that the sheath is composed of neoprene latex.

In particular, it is further preferred that the coil-spring is embedded within the wall of the sheath.

Advantageously, the protective cover is configured so that a safety cap, such as is known in the art, can be fitted over the needle and cover. It is preferred that the cover is designed so that the safety cap can be fitted over the needle with the sheath in either its compressed or extended position.

-3 AMENDEDO

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PCT/AUOO/01252 Received on 23 January 2002 In addition, it is further preferred that the tip of the dipping mould is designed such that, in the dipping step, the latex is not able to flow within the cone but covers the outside only.

It is particularly preferred that the medical grade latex is neoprene latex and that the spring is composed of World Health Organisation-approved stainless steel.

Brief Description of the Drawings: Figure 1 illustrates a protective cover mounted in place on a hypodermic needle. In this view the sheath is in its compressed and latched position.

Figure 2 shows the protective cover of Figure 1 in which the sheath is unlatched and is encasing the needle.

Figure 3 illustrates a dipping mould that is used for forming a neoprene latex sheath.

Figure 4 shows the mould of Figure 3 with a coil-spring mounted in position ready for dipping.

Figure 5 illustrates the configuration of a preferred stainless steel coil-spring for use in the invention.

-4- AMENDED SHED IP '^AU PCT/AUJOO/O 1252 Received on 23 January 2002 Detailed Description with Respect to the Drawings: A hypodermic needle with a protective cover in a compressed, ready for use position is shown in association with a syringe in Figure 1. A similar needle is shown after use, encased by the cover in Figure 2.

In Figure I can be seen a needle having a hub for attachment to a syringe (8) as is known in the art. The protective cover is latched into a compressed position by a cone section latching means having finger tabs to aid in unlatching and a frangible snap seal the breaking of which unlatches the cover.

After use, as shown in Figure 2, pressure is applied to the finger tabs to break the seal and the two halves of the latching means swing away from the cover on hinges By the action of the released coil-spring the sheath of the cover extends until it completely encases the needle shaft Protection for the sharp tip of the needle is provided by the tightly wound conical tip (12) of the coil-spring During assembly of the needle and cover, the neoprene-dipped spring is compressed and housed within the latching means That construction is then fixed to the hub of the needle by the engagement of three "tight" coils located at the open end of the spring with a narrowed shoulder on the hub.

A preferred configuration of a spring (15) is shown in Figure 5 in which can be seen a tightly wound conical tip (12) of about 10 rnu in length and having a tip opening of about 3.2 nmm in diameter. The body of the spring has a 2.36 nm pitch and is of about 35 mm in length and from 5.35 to 5.85 in diameter, At the base end of the spning are three contiguous tightly wound coils (16).

Shown in Figures 3 and 4, is a specially designed dipping mould for use in manufacturing a protective cover according to the invention. The mould is constructed fromn standard stock 316 stainless steel rod. The base of the rod is provided with a drilled and tapped thread (19) to allow the mould to be attached to a AMAENDED) SHEST

IPEAIAU

PCT/AUOO/O 1252 Received on 23 January 2002 holder (not shown). At its tip end, the mould has a conical section (18) that is complementary with the conical tip (12) of the spring Located at a point about 3 5 nmm from the shoulders of the conical section is a rounded rise (17) adapted to engage the tight coils (16) of the spring A conical tipped spring is loaded onto the dipping mould and held in place by the rounded rise (17) as indi cated in Figure 4.

The mould is dipped into a neoprene latex medium of controlled viscosity and gelling strength. The latex viscosity is controlled by the use of a standard efflux tube or by zhan cup timed in various degrees of seconds Whilst gelling strength is controlled by varying the amount by weight of added calcium nitrate.

The neoprene latex is allowed to flow under and over the spring creating a tube sheath of approximately 0.5mm in thickness between the outer side of the spring and the dipping mould. The tight coil-spring cone, in conjunction with the design of the mould, does not allow latex to flow within the cone. The latex covers the outer side only.

After curing, the sheath with its embedded spring is removed from the mould and mounted on a hypodermic needle by a suitable adhesive process, as is known in the art. The sheath is compressed against the bias of the spring, piercing the tapered end of the sheath and allowing the needle to protrude. The sheath is held in this position by the conical latching means.

After use of the needle, when the latching means is disengaged and the sheath is extended, as the sheath passes over the tip of the needle the hole in the latex closes over thus totally encasing the needle and preventing the escape of any contaminating material. In this extended position, because of the structure and configuration of the stainless steel coil-spring, the protective cover has an impact resistance of approximately 15PS1. Other devices in the prior art are only able to withstand pressures of 5PSI or less.

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Claims

Claims:

1 A protective cover for a hypodermic needle comprising:

a flexible, fluid impermeable sheath encasing a needle;

biasing means; and

latching means;

in which the sheath is compressed against the biasing means down the shaft of the needle thereby exposing the needle ready for use and the sheath is latched into that compressed position by the latching means; and

whereas, in use, the needle is inserted into a patient, blood drawn or medication injected, then the latching means is released allowing the sheath to move in response to the biasing means so that, as the needle is withdrawn from the patient, the sheath extends along the needle shaft to a point substantially against the patient's skin and, as the withdrawal of the needle continues, the sheath further extends substantially against the patient's skin until it completely encases the needle.

2 A cover as defined in claim 1 in which the sheath is composed of neoprene latex.

3 A cover as defined in claim 1 in which the biasing means comprises a coil-spring arranged so that the shaft of the needle passes through a lumen formed by the coils.

4 A cover as defined in claim 3 in which the end of the spring that is disposed towards the tip end of the needle is a tightly wound cone of suitable dimensions to enclose and provide protection to the needle tip.

5 A cover as defined in claims 3 or 4 in which the coil-spring is embedded within the wall of the sheath. A cover as defined in claims 1 or 3 in which the protective cover is configured so that a safety cap, such as is known in the art, can be fitted over the needle and cover.

A cover as defined in claim 6 in which the cover is designed so that the safety cap can be fitted over the needle with the sheath in either its compressed or extended position.

A method for the manufacture of a protective cover for a hypodermic needle comprising:

providing a dipping mould and a coiled spring;

attaching the spring to the dipping mould;

providing a medical grade latex medium of selected appropriate conditions of viscosity and gelling strength; and

dipping the mould and attached spring into the latex medium in such a manner that the latex flows under and over the spring thereby forming a tube with the spring embedded in its wall.

A method as defined in claim 8 in which the coil-spring is provided with a tight coil-spring cone at its outer end.

A method as defined in claims 8 or 9 in which the tip of the dipping mould is designed such that, in the dipping step, the latex is not able to flow within the cone but covers the outside only.

A method as defined in claims 8 or 9 in which the medical grade latex is neoprene latex and the spring is composed of World Health Organisation-approved stainless steel.