GB2208604A - Medical syringe - Google Patents

Abstract

There is disclosed a medical syringe (10) having a protective sleeve (11) and adapted to have a sterilised needle (12) coupled therewith. The syringe (10) comprises a cylindrical barrel (13) in which a plunger (14) is linearly reciprocable. The protective sleeve (11) is capable of fitting over a used needle (12) when the latter is coupled with the syringe, and of making snap-locking engagement with the syringe barrel (13) when the needle (12) is wholly enclosed by the sleeve (11). <IMAGE>

Description

MEDICAL SYRINGE This invention relates to a medical syringe for use in withdrawing a body fluid from a patient, or for injecting a medical fluid into a patient.

It is known to supply syringes in sealed protective sleeves, and to arrange for a seal to be broken (and for this to be visibly evident) before the syringe can be used.

Usually, a needle is also supplied in a similar packaging of a "tamper evident" sleeve, so that the person using a syringe and needle taken from sealed sleeves can be assured of a satisfactory level of sterility and the absence of unauthorised handling of the components prior to use.

The syringe and needle are manufactured on a single use basis, and are intended to be disposed of after use.

Safe disposal can be a problem, both during initial handling by the person who used the components, and also by any further personnel involved in the handling of the components during final disposal.

The advent of the Aids virus has brought about a recognition of how vital it is to ensure that the virus does not become passed-on from a patient to any medical personnel involved in treating and looking after the patient, but it is just as important that other highly dangerous diseases should not be passed-on from a patient by any medical equipment, and particularly syringe needles, which have been used in the treatment of the patient.

However, as is now widely recognised, the Aids virus can apparently be transmitted from a blood sample taken from an infected patient, and it is therefore particularly important that the risk should be avoided of passing the virus from a needle which has been used for injecting a patient, or withdrawing fluid from a patient.

Used disposable needles can be inserted into protective sleeves for disposal purposes, but this requires manual manipulation of the needles, with consequent risk of the handler scratching his skin with the tip of the needle, which may be carrying an infected blood sample.

There is therefore a clear need to provide a protective device which enables the needle to be safely enclosed after use in a manner which avoids the necessity for the user to make any direct manipulation of the needle.

According to the invention there is provided a medical syringe having a protective sleeve, the syringe being adapted to have a sterilised needle coupled therewith; in which the syringe comprises a cylindrical barrel in which a plunger is linearly reciprocable, and the protective sleeve is capable of fitting over a used needle when the latter is coupled with the syringe, and of making snap-locking engagement with the syringe barrel when the needle is enclosed by the sleeve.

Therefore, following coupling-up of a needle to the syringe, and use thereof (to withdraw a sample of body fluid from a patient, or to inject a medical treatment fluid into the patient), the protective sleeve can be fitted over the needle without the need for any direct manual manipulation of the needle to take place, and can then be locked to the syringe barrel with the needle tip completely housed therein against risk of possible contact with anyone involved in the subsequent disposal of the used syringe and needle.

In one preferred embodiment, the syringe barrel is slidably mounted in the protective sleeve, and after use the barrel and the sleeve can be moved longitudinally relative to each other (without any direct finger engagement with the needle being required) so as to extend the sleeve over the needle and a sufficient safe distance beyond the needle tip to avoid any possibility of inadvertent flesh contact being made with the tip subsequently.

Preferably, a lock cap may be provided for application to the free end of the protective sleeve, when the needle is enclosed therein, and advantageously this is by means of a snap-lock fitting which cannot readily be, or become uncoupled.

Preferably, a first locking component is provided on the barrel and a corresponding second locking component is provided on the sleeve at a suitable position to achieve snap-locking engagement when the sleeve is advanced (by relative movement of the sleeve and barrel) so as to completely enclose the needle.

The snap-locking engagement between the first and second locking components should be such that they also cannot readily be, or become uncoupled.

The first locking component may comprise a circumferential projection on the barrel, in which case the second locking component may comprise a corresponding receiving recess provided at a suitable position on the internal surface of the protective sleeve. However, evidently the first locking component may comprise the receiving recess and the second locking component may comprise the projection.

In a particularly convenient arrangement, the projection comprises an annular ridge arranged at the "needle end" of the barrel, and the recess comprises an annular groove in the inner wall of the sleeve and which is located at or near an end of the sleeve which is near the opposite. end of the barrel, prior to relative advance of the sleeve over the needle.

In another preferred embodiment of the invention, the protective sleeve takes the form of a rigid or semi-rigid protective sheath having an enlarged mouth through which the used needle can be guided relatively safely (with the sheath being held at a position considerably removed from the mouth of the sheath to avoid any risk of penetrating the skin by careless presentation of the needle to the sheath). Following complete enclosure of the needle within the sheath, suitable snap-locking can then take place between the barrel and the sheath.

In one preferred arrangement of this further embodiment, a radially outwardly extending projection may be slidably mounted on the barrel for movement to a position of locked engagement on the barrel, and this position will be arranged such that, upon complete enclosure of the needle within the sheath, the projection can make locking engagement with a locking recess in the mouth of the sheath.

This further embodiment is particularly advantageous, in that the sheath provides complete enclosure of the used needle without the need for any further closure component to be fitted, and it is of course advisable for handling operations to be kept to a minimum so as to reduce the risk of any physical contact occurring between the user and the tip of a used needle.

Furthermore, the protective sheath may also serve as a syringe cover in which the syringe can be stored in a sterile condition ready for use, in which case preferably a disposable end cap is provided which fits over the mouth of the cover (sheath) and which has a seal which must be broken before the syringe is removed.

Accordingly, both of the embodiments disclosed herein provide the following advantages: 1. both the syringe and the needle are encapsulated in a rigid cover (normally only the needle is covered); 2. the rigid cover offers protection against any pricking by the needle and spillage of any residuals in the syringe (this latter is an additional safety feature not included in syringe systems presently available); 3. the rigid cover is fixedly secured in position and cannot be removed without breaking the syringe using force, and it is therefore tamper-proof. It may also have value in avoiding re-use in a drug addiction situation; 4. the act of applying the cover over the needle provides a safe "disarming" action.

Embodiments of syringe according to the invention will now be described in detail, by way of example only, with reference to the accompanying drawings, in which: Fig 1 is a side view of a first embodiment of syringe according to the invention, having a needle coupled therewith ready for treating a patient; Fig 2 is a side view showing a protective sleeve extended to a position of enclosure with respect to a used needle; Fig 3 is a side view of a second embodiment of syringe according to the invention, enclosed within a protective sleeve intended for subsequent enclosure of a used needle while attached to the syringe; and Fig 4 is a view of the second embodiment, showing the used needle wholly enclosed within the protective sleeve.

Referring now to Figs 1 and 2 of the drawings, a first embodiment of medical syringe according to the invention is designated generally by reference 10 and has a protective sleeve 11, the syringe being adapted to have a sterilised needle 12 coupled therewith in any well known or convenient manner. The syringe 10 comprises a cylindrical barrel 13 in which a plunger 14 is linearly reciprocable in order to inject a medical treatment fluid into a patient, or to withdraw a body fluid sample from a patient.

As will be described in more detail below, the protective sleeve 11 is capable of fitting over the needle 12, after use, while the latter remains coupled with the syringe, and is also able to make snap-locking engagement with the syringe barrel 13 when the needle 12 is wholly enclosed by the sleeve 11, as shown in Fig 2.

The syringe barrel 13 is slidably mounted in the protective sleeve 11, and after use the barrel 13 and the sleeve 11 can be moved longitudinally relative to each other so as to extend the sleeve 11 over the needle 12 and a sufficient safe distance beyond the needle tip 15 to avoid any possibility of inadvertent flesh contact being made with the tip subsequently. A lock cap 16 is provided for application to the free end 17 of the sleeve 11 so as to completely enclose the needle 12 and form a protective sheath with the sleeve 11. A snap-lock type fitting may be provided between the cap 16 and the free end 17 so as to prevent the cap from becoming uncoupled.

Snap-locking engagement is provided between the barrel 13 and the sleeve 11, when the sleeve is in the enclosure position with respect to the needle 12, and this is provided by a first locking component 18 on the barrel 13 and a second locking component 19 formed in the inner wall of the sleeve 11. The first locking component 18 comprises an annular ridge extending around the circumference of the barrel 13, adjacent the needle end thereof, whereas the second locking component 19 comprises an internal annular groove at the end of the sleeve 11 remote from the needle end. The engagement between the first and second locking components 18,19 is such that the sleeve 11 is maintained reliably locked in position shielding anyone from coming into contact with the needle 12.

A twist lock cap 20 may be provided which shields the non-needle end of the barrel 13, and forms a protective enclosure for the syringe 10 prior to use.

Referring now to Figs 3 and 4, a further embodiment of the invention is designated generally by reference 21, and parts corresponding with those already described are designated by the same reference numerals, and will not be described in detail again. In this embodiment, the protective sleeve takes the form of a rigid or semi-rigid protective sheath 22 which has an enlarged mouth 23 through which the used needle 12 can be guided relatively safely, with the sheath 22 being held between the fingers at a position considerably removed from the mouth 23, to avoid any risk of penetrating the skin by careless presentation of the needle 12 to the sheath. Following complete enclosure of the needle 12, as shown in Fig 4, suitable snap-locking takes place between the barrel 13 and the sheath 22.

To this end, a radially outwardly extending projection, in the form of an interference fit disc 24, is slidably mounted on the barrel 13 for movement to a position of locked engagement on the barrel, this position being arranged so that, upon complete enclosure of the needle 12 within the sheath 22 as shown in Fig 4, the projection 24 makes locking engagement with a locking recess in the mouth 23 of the sheath 22, and taking the form of an annular fitting groove 25.

A further feature of this embodiment is that the sheath 22 provides complete enclosure of the used needle 12 without the need for any further closure component to be fitted. Furthermore, the sheath 22 also serves as a syringe cover in which the syringe can be stored in a sterile condition ready for use, and therefore a disposable end cap 26 is provided which fits over the mouth 23 of the cover (sheath) and which has a seal (not shown) which must be broken before the syringe is removed.

When long needles are to be used with either embodiment, such as a 2.5 inch needle, it may be desirable for the protective sleeve to be telescopic so as to be able to be extended completely over and beyond the tip of the needle.

Claims (10)

1. A medical syringe having a protective sleeve, the syringe being adapted to have a sterilised needle coupled therewith; in which the syringe comprises a cylindrical barrel in which a plunger is linearly reciprocable, and the protective sleeve is capable of fitting over a used needle when the latter is couled with the syringe, and of making snap-locking engagement with the syringe barrel when the needle is enclosed by the sleeve.

2. A medical syringe according to Claim 1, in which the syringe barrel is slidably mounted in the protective sleeve, whereby the barrel and the sleeve can be moved longitudinally relative to each other after use so as to extend the sleeve over the needle and a sufficiently safe distance beyond the needle tip to avoid any possibility of inadvertent flesh contact being made with the tip subsequently.

3. A medical syringe according to Claim 1 or 2, in which a lock cap is provided for application to the free end of the protective sleeve, when the needle is enclosed therein.

4. A medical syringe according to any one of the preceding claims, in which a first locking component is provided on the barrel and a corresponding second locking component is provided on the sleeve at a suitable position to achieve snap-locking engagement when the sleeve is advanced so as to completely enclose the needle.

5. A medical syringe according to Claim 4. in which the first locking component comprises a circumferential projection on the barrel, and the second locking component comprises a corresponding receiving recess provided at a suitable position on the internal surface of the protective sleeve.

6. A medical syringe according to Claim 5, in which the projection comprises an annular ridge arranged at the needle end of the barrel, and the recess comprises an annular groove in the inner wall of the sleeve and which is located at or near an end of the sleeve which is near the opposite end of the barrel, prior to relative advance of the sleeve over the needle.

7. A medical syringe according to Claim 1, in which the protective sleeve takes the form of a rigid or semirigid protective sheath having an enlarged mouth through which the used needle can be guided.

8. A medical syringe according to Claim 7, in which a radially outwardly extending projection is slidable mounted on the barrel for movement to a position of locked engagement on the barrel, and this position is arranged such that, upon complete enclosure of the needle within the sheath, the projection can make locking engagement with a locking recess in the mouth of the sheath.

9. A medical syringe according to Claim 8, in which the protective sheath serves as a syringe cover in which the syringe can be stored in a sterile condition ready for use, and a disposable end cap is provided for fitting over the mouth of the sheath and has a seal which must be broken before the syringe can be removed.

10. A medical syringe according to Claim 1 and substantially as hereinbefore described with reference to, and as shown in any one of the embodiments illustrated in the accompanying drawings.