WO1998031410A1

WO1998031410A1 - Syringe

Info

Publication number: WO1998031410A1
Application number: PCT/GB1998/000020
Authority: WO
Inventors: Edward Butters
Original assignee: Phoenix Medical Limited
Priority date: 1997-01-16
Filing date: 1998-01-13
Publication date: 1998-07-23
Also published as: AU5490298A; GB9700789D0

Abstract

A syringe (310) comprises a barrel (312), a plunger (314) having a seal (316), a needle stem (318) which is moulded with the barrel (312) and a needle (320) mounted on the stem (318). The needle (320) can be removed from the stem (318) so that it is contained within the plunger (314).

Description

Syringe

The present invention relates to syringes. In particular the present invention relates to hypodermic syringes of the disposable variety. This type of syringe is now common place and is widely used throughout the world. It has many advantages. It can be supplied ready sterilised and in sterile packaging. It is relatively cheap. It is easy to use and does not require re- sterilising since it is disposed of after use.

However it does have a number of disadvantages. The needles themselves (or 'sharps' as they are known) can still cause a wound, accidentally or otherwise. If the sharp is contaminated, a wound caused by a sharp can result in infection. It is still possible to re-use the syringe with all the consequent dangers, and the syringe can leak with the possibility again of causing infection.

A number of proposals have been made for the safe and effective disposal of sharps. These include the provision of a box which enables the sharp to be safely detached from the body of the syringe so that the sharp falls into the box which is otherwise sealed. Another approach has been to withdraw the sharp into the barrel of the syringe after use.

Whilst another proposal has been to accommodate the sharp within the syringe plunger by removing the plunger from the barrel and locating and securing the sharp in a lateral opening in the plunger enabling the sharp to be detached from the syringe barrel, and the plunger and retained sharp reinserted into the syringe barrel.

All these proposals have apparent advantages but suffer from disadvantages as well. In most if not all cases it is still possible to re-use the syringe and the syringe is not sealed thereby allowing the possibility of leakage of blood and contaminated liquids which may cause infection. Also it may still be possible for the sharp to cause an injury whilst it is being detached from the barrel of the syringe.

The present invention seeks to provide a disposable syringe which enables the sharps to be safely disposed, which can not be reused, and which provides a safe containment for blood and other contaminated liquids.

According to the present invention there is provided a disposable syringe comprising, a barrel, a plunger located in and movable within the barrel, a needle removably located at an extremity of the barrel, the plunger having an open end and gripping means in the open end, the plunger being removable from the barrel and locatable longitudinally over the needle enabling the gripping means to retain the needle within the plunger upon relative movement of the plunger and barrel, the plunger and retained needle being reinsertable within the barrel, the plunger having a detachable seal and the plunger and the seal having means to engage one another enabling the plunger and seal to be attached together in a first mode of operation and for the seal to be detached from the plunger and retained in the barrel, in a second mode of operation.

The plunger can have a shoulder engagable by flexible gripping means on the seal to retain the seal on the plunger in the first mode of operation and means to release the gripping means to detach the seal from the plunger in the second mode of operation.

The release means can comprise a collar slidably mounted on the plunger which can displace the flexible gripping means to an open position releasing the seal from the plunger in the second mode of operation.

The collar can be forced into and retained by the flexible gripping means in the second mode of operation.

The barrel of the syringe can be provided with a slidable sleeve, the sleeve having attachment means at one end enabling the plunger to be removed from the barrel and to be attached to the sleeve, the plunger having gripping means engagable with the needle to detach the needle from the barrel by relative movement of the sleeve and plunger assembly and the barrel so that the needle is retained within the plunger.

The present invention will now be more particularly described with reference to the accompanying drawings in which

Figures 1, 2 and 3 show diagrammatic elevations of a disposable syringe according to the present invention, and

Figures 4, 5 6, 7 and 8 show diagrammatic elevations of a modification to the syringe shown in Figures 1, 2 and 3.

Referring to Figures 1 , 2 and 3 , there is shown a disposable syringe (310) comprising a barrel (312) , a plunger (314) having a seal (316) , a needle stem (318) which is moulded with the barrel, and a needle (320) mounted on the stem (318) .

The seal (316) is removably retained upon the plunger (314) in the following way. The plunger (314) is provided with a spigot (330) having a shoulder (332) at its upper end and an enlarged circular pointed head (334) at its lower end. A collar (336) is loosely mounted on the spigot (330). A collar has an internal diameter which is larger than the outer diameter of the head (334) but is smaller than the diameter of the shoulder (332) .

The seal (316) is provided with a retaining means in the form of a number of equispaced radially extending flexible fingers (338) which are engagable by the head (334) and the collar (336) as will be described below.

Referring particularly to Figure 1 it will be seen that the plunger (314) and seal (316) are attached together by means of the head (334) on the spigot (330) being inserted through the flexible fingers (338) whilst the collar (336) is loosely held on the spigot (330) between the fingers (338) and the shoulder (332) .

In a first mode of operation with the components of the syringe being attached together as shown in Figure 1 and in the position shown in Figure 1 the plunger (314) and seal (316) are withdrawn in direction of the arrow in Figure 1 enabling medication to be drawn through the needle (320) into the barrel (312) of the syringe. The plunger (314) and the seal (316) are attached together in this mode of operation by the underside of the head (334) engaging the fingers (338) .

In order to dispense the medication, referring to Figure 2, the plunger (314) is depressed in the direction of the arrow in Figure 2 and the collar (336) is forced through the fingers (338) of the retaining means, displacing the flexible fingers permanently into an open position. With the lower end of the plunger engaging the upper surface of the seal (316) , the seal is forced downwardly through the barrel (312) enabling the medication within the barrel to be dispensed through the needle (320) . Referring particularly to Figure 3, as the fingers (338) of the retaining means are held in the open position by means of the collar (336) the plunger can be withdrawn in the direction of the arrow in Figure 3 through the barrel (312) leaving the seal (316) in position in the barrel because the head (334) is smaller in diameter than the internal diameter of the collar (336) .

As with the corresponding arrangements in application number 9611986.2 the seal (316) is secured in position and prevents leakage of liquids from the barrel.

Figures 4 to 8 inclusive show a means of safely removing the needle from the barrel and to retain the removed needle within the plunger.

Referring to Figures 4 to 8 inclusive and in particular to Figure 4 there is shown a disposable syringe (410) comprising a barrel (412) , a plunger (414) having a seal (416) , a needle stem (418) which is moulded with the barrel and a needle (420) mounted on the stem (418) . The seal (416) is removably retained upon the plunger 414) in an identical manner to that described with reference to Figures 1, 2 and 3 by means of the spigot (430) which corresponds to the spigot (330) .

The syringe (410) is also provided with a sleeve (440) which can slide axially on the barrel and preferably is prevented from rotating on the barrel and being removed from the barrel by a suitable means e.g. locating lugs and a retaining collar. The lower end of the sleeve is provided with retaining means in the form of two part-circumferential slots (442) the function of which is to enable the plunger (414) to be attached to the sleeve

(440) as will be described below.

The overall purpose of the provision of the sleeve (440) is to enable the needle (420) to be removed from the barrel (412) in a safe manner.

Referring particularly to Figures 4 and 5, the sleeve (440) is moved axially on the barrel from the position shown in Figure 4 to that shown in Figure 5. The plunger (414) is withdrawn from the barrel (412) and is attached to the end of the sleeve (440) by means of the rim (414a) of the plunger (414) engaging in the slots (442) .

The assembly of the sleeve (440) and the plunger (414) can then be moved on the barrel (412) so that the needle passes through the flexible fingers (414c) to the position shown in Figure 6 where the fingers (414c) are located behind the base of the needle (420) . It will be appreciated that once the sleeve (440) is moved to its extremity at the end of the barrel (412) the needle (420) will be covered. As soon as the plunger (414) is attached to the sleeve (440) and the assembly is moved towards the position shown in Figure 4, the needle (420) will be enclosed within the assembly.

When the position of the assembly as shown in Figure 6 is reached the assembly can be moved to the position shown in Figure 7 and the needle (420) will be removed from the stem (418) by the engagement of the fingers (414c) with the base of the needle and the needle (420) will fall to the bottom of the plunger (414) as shown in Figure 7.

The plunger (414) can then be removed from the sleeve (440) and inserted within the barrel (412) and the sleeve (440) can be restored to its original position as shown in Figure 8.

The needle has thus safely been removed from the stem (418) and is safely retained within the plunger (414) .

It will be appreciated that not only has the syringe been used in a safe manner but also that the needle has been removed in a safe manner. The needle cannot be removed without breaking the plunger and the plunger and seal (416) cannot be attached together again without the collar (316) having to be removed from the flexible fingers (338) .

For all practical purposes this means that the syringe cannot be used again because it is not possible to reassemble the syringe to the state shown in Figure 1 without compromising the integrity of at least one of the components of the syringe.

Claims

1. A disposable syringe comprising, a barrel, a plunger located in and movable within the barrel, a needle removably located at an extremity of the barrel, the plunger having an open end and gripping means in the open end, the plunger being removable from the barrel and locatable longitudinally over the needle enabling the gripping means to retain the needle within the plunger upon relative movement of the plunger and barrel, the plunger and retained needle being reinsertable within the barrel, the plunger having a detachable seal and the plunger and the seal having means to engage one another enabling the plunger and seal to be attached together in a first mode of operation and for the seal to be detached from the plunger and retained within the barrel in a second mode of operation.

2. A syringe as claimed in claim 1 in which the plunger has a shoulder engagable by flexible gripping means on the seal to retain the seal on the plunger in the first mode of operation and means to release the gripping means to detach the seal from the plunger in the second mode of operation.

3. A syringe as claimed in 2 in which the release means comprises a collar slidably mounted on the plunger, the flexible gripping means being displaceable to an open position by movement of the collar to release the seal from the plunger in the second mode of operation.

4. A syringe as claimed in claim 3 in which the collar is forced into and retained by the flexible gripping means in the second mode of operation.

5. A syringe as claimed in any one of the preceding claims in which the barrel of the syringe includes a slidable sleeve, the sleeve having attachment means at one end enabling the plunger to be removed from the barrel and to be attached to the sleeve, the plunger gripping means being engagable with the needle to detach the needle from the barrel by relative movement of the sleeve and plunger assembly and the barrel so that the needle is retained within the plunger.

6. A syringe as claimed in claim 5 in which the plunger is detachable from the sleeve and reinsertable within the barrel of the syringe.

7. A disposable syringe constructed and arranged for use and operation substantially as herein described and with reference to the accompanying drawings.