WO2010110743A1

WO2010110743A1 - Safety guard for a syringe needle

Info

Publication number: WO2010110743A1
Application number: PCT/SG2010/000096
Authority: WO
Inventors: Ge Chen; Fei Min Chong; Ming Shyan John Yong; Mun Wai Lee
Original assignee: Agency For Science, Technology And Research
Priority date: 2009-03-25
Filing date: 2010-03-17
Publication date: 2010-09-30

Abstract

A safety guard for a syringe needle. The safety guard comprises a barrel for releasably attaching the safety guard to a syringe; a sleeve for encasing the needle, the sleeve being configured for slidable, rotatable and lockable engagement with the barrel; a resilient element for biasing the sleeve distally and rotationally with respect to the barrel; and a stopper to prevent locking of the sleeve with the barrel prior to use of the needle, wherein the sleeve is configured to rotate to a return state in anticipation of locking with the barrel after use of the needle.

Description

SAFETY GUARD FOR A SYRINGE NEEDLE

Field of the Invention

The invention relates to a safety guard for a syringe needle and particularly, though not exclusively, relates to a safety guard for a syringe needle used with a pre- filled cartridge.

Background

Medical care of individuals requires the widespread use of needles with syringes for injecting or removing a fluid. The use of a hypodermic needle typically includes inserting a needle into the patient, injecting a substance or withdrawing the fluid as required, and then removing the needle from the patient, hi most applications, the withdrawn needle must be handled very carefully during disposal to avoid needle stick injury and possible risk of contamination of a healthcare worker using the needle and syringe on a patient.

To help prevent healthcare workers from being injured, guards have been developed to block the tips of syringe needles after use. Such guards fall into three basic categories: those that withdraw the needle into the barrel of the syringe after use; those with a hinged needle guard which rotates into position over the needle; and those with a sliding shield which moves along the needle shaft and covers its tip. The guards may be manually moved into position by the user or given mechanical assistance such as, for example, by the use of springs or suction. A problem with manually activated designs is that they require the user to either slide or apply the needle shield to the tip of the needle by hand, significantly raising the risk of unintentional contact with the needle tip. There is also a danger of the user forgetting to activate the device. In addition, many of these needle guards interfere with the ability to use the syringe with single hand.

Some designs have been proposed to provide protection before and after use. These are generally operated manually or are spring biased to extend a tubular shield and enclose the needle. These systems mainly include spiral or complicated channels cut into the shield to guide it during extension and lock it in the extended position. A problem with these designs is that the track systems may not always be reliable.

Furthermore, it often happens that a first needle is required to load the syringe with a substance for injection while a second needle is used to inject the substance into a patient. Changing of needles necessarily increases risk of needle stick injury.

Summary of the Invention

According to a first exemplary aspect, there is provided a safety guard for a syringe needle. The safety guard comprises a barrel for releasably attaching the safety guard to a syringe; a sleeve for encasing the needle, the sleeve being configured for slidable, rotatable and lockable engagement with the barrel; a resilient element for biasing the sleeve distally and rotationally with respect to the barrel; and a stopper to prevent locking of the sleeve with the barrel prior to use of the needle, wherein the sleeve is configured to rotate to a return state in anticipation of locking with the barrel after use of the needle. The syringe preferably comprises a pre-loaded cartridge and the safety guard preferably further comprises the needle, the needle being attached to the barrel and having a free proximal end for insertion into the pre-loaded cartridge when the barrel is attached to the syringe, the needle further being stationary with respect to the syringe when inserted into the preloaded cartridge.

According to a second exemplary aspect, there is provided a syringe assembly comprising a syringe, a needle and a safety guard. The safety guard of the syringe assembly comprises a barrel for releasably attaching the safety guard to the syringe; a sleeve for encasing the needle, the sleeve being configured for slidable, rotatable and lockable engagement with the barrel; a resilient element for biasing the sleeve distally and rotationally with respect to the barrel; and a stopper to prevent locking of the sleeve with the barrel prior to use of the needle, wherein the sleeve is configured to rotate to a return state in anticipation of locking with the barrel after use of the needle. The syringe preferably comprises a pre-loaded cartridge and the needle is preferably attached to the barrel, wherein the needle has a free proximal end for insertion into the pre-loaded . cartridge when the barrel is attached to the syringe, the needle further being stationary with respect to the syringe when inserted into the preloaded cartridge.

For both aspects, the safety guard preferably comprises snap fit provisions on the sleeve and the barrel such that the sleeve locks with the barrel by engagement of the snap fit provisions to prevent proximal movement of the sleeve with respect to the barrel. The snap fit provisions may comprise at least one cantilever snap on the sleeve and a corresponding hole in the barrel. The stopper preferably comprises a projection on the barrel and a projection on the sleeve configured to act against each other to prevent movement of the sleeve with respect to the barrel, thereby preventing engagement of the snap fit provisions. The projection on the sleeve and the projection on the barrel preferably comprise a ring and a tab. The ring preferably comprises a slot for allowing passage of the tab therethrough to allow engagement of the snap fit provisions, the slot being positioned on the ring such that the tab axially aligns with the slot only after rotation of the sleeve to the return state.

One of the projection on the sleeve and the projection on the barrel preferably include a notch for rotationally acting against the other of the projection on the sleeve and the projection on the barrel, so as to prevent rotation of the sleeve prior to use of the needle.

The barrel preferably comprises a first section for engaging the sleeve and a second section for attachment to the syringe, the first section and second section being separable.

Brief Description of the Drawings

In order that the invention may be fully understood and readily put into practical effect there shall now be described by way of non-limitative example only exemplary embodiments of the present invention, the description being with reference to the accompanying illustrative drawings.

Li the drawings: FIG. 1 is a schematic perspective view of an exemplary embodiment of a safety guard for a syringe needle in assembly with a syringe; FIG. 2 is an exploded view of the assembly of FIG. 1; FIG. 3 is a schematic cross-sectional side view of the safety guard of FIG. 1 in an initial state 100;

FIG. 4 is a schematic perspective view of a sleeve of the safety guard of FIG. 1; FIG. 5 is a schematic side view of a stopper of the safety guard of FIG. 1 in the initial state 100 of FIG. 3; FIG. 6 is a schematic cross-sectional side view of the safety guard of FIG. 1 after use of the needle before a return state 300;

FIG. 7 is a schematic side view of a stopper of the safety guard of FIG. 6 FIG. 8 is a schematic cross-sectional side view of the safety guard of FIG. 1 in a return state 300;

FIG. 9 is a schematic side view of a stopper of the safety guard of FIG. 8; FIG. 10 is a schematic cross-sectional side view of the safety guard of FIG. 1 in an end and locked state 400; and FIG. 11 is a schematic side view of a stopper of the safety guard of FIG. 10.

Detailed Description of the Exemplary Embodiments

An exemplary embodiment of a safety guard 10 for a syringe needle 92 will be described with reference to FIGS. 1 to 11.

As shown in FIGS. 1 to 3, the safety guard 10 comprises a sleeve 20 and a barrel 30 that are both preferably co-axial with a longitudinal axis 8 of the needle 92. The sleeve 20 is configured for slidable, rotatable and lockable engagement with the barrel 30. A portion of the sleeve 20 extends distally beyond the barrel 30. The sleeve 20 is generally cylindrical. The sleeve 20 is generally hollow for encasing the needle 92 and is provided with an opening 22 at a distal end 21 of the sleeve 20 for passage of the needle 92 therethrough. A narrowed canula 23 may be provided adjacent the distal end 21 of the sleeve 20 to provide a sliding fit with the needle 92 so as to support and guide movement of the needle 92 through the safety guard 10.

The barrel 30 is configured for releasably attaching the safety guard 10 to a syringe 90, and may comprise a first section 32 and a second section 34. Preferably, the first section 32 connects with the second section 34 via snap fit provisions 36 as shown in FIG. 2. The snap fit provisions 36 may comprise annular or cantilever snaps 37 on the second section 34 for fitting in a corresponding annular recess 38 on the first section. The second section 34 preferably comprises an internally threaded hole 39 for screwing a proximal portion 65 of the barrel 30 onto a corresponding threaded distal end 95 of the syringe 90. Alternatively, a standard attachment mechanism such as, for example, a Luer-type connector, may be used by providing appropriate Luer lock formations on the barrel 30 and syringe 90.

The safety guard 10 includes a resilient element 40 such as a compression spring 40 for biasing the sleeve 20 rotationally about the longitudinal axis 8, as indicated by the arrow 7, and also distally along the longitudinal axis 8 with respect to the barrel 30, as indicated by the arrow 2. The compression spring 40 is preferably mounted on a centrally disposed mounting boss 42 in the second section 34 of the barrel. The compression spring 40 preferably engages the sleeve 20 by fitting in a centrally disposed spring mounting recess 24 at a proximal end 25 of the sleeve 20 as shown in FIG. 3. Proximal sliding of the sleeve 20 with respect to the barrel 30 as indicated by the arrow 4 along the longitudinal axis 8 therefore requires compression of the compression spring 40.

The sleeve 20 includes a projection 50 comprising preferably a radially extending ring 50 around the sleeve 20. The barrel 30 includes a projection 60 comprising preferably a tab 60 that may be located at a distal end 61 of the barrel 30. The projection 60 on the barrel 30 and the projection 50 on the sleeve 20 are configured to act against each other to prevent movement such as rotation 7 of the sleeve 20 or sliding of the sleeve 20 distally 2, despite the bias introduced by the compression spring 40 on the sleeve 20.

To prevent the sleeve 20 from sliding distally 2, as shown in FIG. 5, the tab 60 and the ring 50 are located such that the tab 60 is distal to the ring 50 when the barrel 30 and the sleeve 20 are assembled. However, the ring 50 may be provided with a slot 51 as shown in FIG. 4 to allow passage of the tab 60 therethrough, so that after use of the needle 92, the sleeve 20 is displaced distally 2 when compared to an initial state 100 prior to use of the needle 92. The slot 51 should be located in the ring 50 such that it is axially misaligned with the tab 60 when the sleeve 20 and the barrel 30 are first assembled into the initial state 100, as shown in FIG. 5. The slot 51 should only axially align with the tab 60 after use of the needle 92 as shown in FIG. 9, due to relative rotation of the sleeve 20 with respect to the barrel 30 after use of the needle 92. To prevent rotation 7 of the sleeve 20 about the longitudinal axis 8, the ring 50 preferably includes a notch 52 into which the tab 60 fits when the sleeve 20 and the barrel 30 are in the initial state 100, as shown in FIG. 5. The notch 52 acts rotationally against the tab 60 so that the sleeve 20 may not rotate relative to the barrel 30.

To lock the sleeve 20 with the barrel 30 in an end state 400 after use of the needle 92, the sleeve 20 and the barrel 30 are preferably provided with snap fit provisions 53,63 comprising at least one cantilever snap 53 and a corresponding hole 63, such that engagement of the snap fit provisions 53,63 prevents the sleeve 20 from sliding proximally with respect to the barrel 30, i.e. along the longitudinal axis 8 in the direction as indicated by the arrow 4 in FIG. 2. By preventing proximal 4 movement of the sleeve 20, the sleeve 20 cannot be pushed into the barrel 30 to expose the needle 92, thereby preventing accidental needle stick injury.

hi the preferred embodiment, a pair of diametrically opposite cantilever snaps or flanges 53 are provided on the sleeve 20 at the proximal end 25 of the sleeve 20 while a pair of diametrically opposite corresponding holes 63 are provided on the barrel 30 in the first section 32. The snap fit provisions 53,63 are located on the sleeve 20 and the barrel 30 such that at the initial state 100 as shown hi FIGS. 3 and 5, the snap fit provisions 53,63 are misaligned and cannot engage each other. In the initial state 100, the sleeve 20 is thus not locked with the barrel 30 and the sleeve 20 may move only proximally 4 upon application of a force against the distal end 21 of the sleeve 20. However, the snap fit provisions 53,63 are positioned on the sleeve 20 and the barrel 30 such that the snap fit provisions 53,63 become axially aligned with one another when the sleeve 20 has rotated 7 to a return state 300 shown in FIG. 8 and FIG. 9, in anticipation of locking with the barrel 30 at the end state 400.

In use, when the sleeve 20 and the barrel 30 are first assembled to be at the initial state 100 as shown in FIG. 3 and FIG. 5, the compression spring 40 is compressed so that the sleeve 20 is biased distally 2. However, distal movement 2 of the sleeve 20 is prevented by the ring 50 engaging the tab 60 as described above. A torque is also introduced into the compression spring 40 so that the sleeve 20 is biased to rotate with respect to the barrel 30. However, rotation of the sleeve 20 is prevented by the tab 60 engaging the notch 52 in the ring 50 as described above. In the initial state 100, the needle 92 is entirely encased by the sleeve 20 and does not extend beyond the distal end 82 of the sleeve 20. Also, in the initial state 100, snap fit provisions 53,63 are misaligned as described above, so that the sleeve 20 may move proximally 4 with respect to the barrel 30. The projection 60 on the barrel 30 and the projection 50 on the sleeve 20 together form a stopper 70 in the safety guard 10 to prevent locking of the sleeve 20 with the barrel 30 prior to use of the needle 92.

During use of the needle 92 as shown in FIG. 6, the distal end 21 of the sleeve 20 is pressed against a patient's skin 99. Pressure 6 of the skin on the distal end 21 causes the sleeve 20 to slide proximally 4 with respect to the barrel 30. This exposes the needle 92 which pierces the patient's skin 99 to inject or withdraw a substance as required. Proximal sliding 4 of the sleeve 20 compresses the compression spring 40 and disengages the ring 50 from the tab 60, such that the tab 60 no longer fits in the notch 52 in the ring 50, as shown in FIG. 7. For greater patient comfort, when the sleeve 20 is in a folly depressed state 200 as shown in FIG. 7 and the needle 92 is in the patient, even though the notch 52 no longer acts against the tab 60 to prevent rotation of the sleeve 20, nevertheless, contact of the distal end 21 of the sleeve 20 with the patient's skin preferably provides sufficient frictional force to resist the torque of the compression spring 40 and prevent rotation of the sleeve 20. The torque introduced in the compression spring 40 during assembly of the safety guard 10 should preferably be small enough such that the sleeve 20 rotates to the return state 300 only upon withdrawal of the needle 92 and there is reduced or no frictional contact of the sleeve 20 with the patient's skin, as shown in FIGS. 8 and 9. Preferably, the torque is configured to rotate the sleeve 20 by an angle of about 10° in the return state 300. When the sleeve 20 is in the return state 300 after use of the needle 92, the tab 60 and the slot 51 become axially aligned as shown in FIG. 9. The snap fit provisions 53,63 also become axially aligned.

When the needle 92 is withdrawn from the patient, as shown in the return state 300 in FIGS. 8 and 9, the sleeve 20 slides distally 2 as a result of the bias in the compression spring 40. During distal sliding 2of the sleeve 20, the tab 60 and the slot 51 remain axially aligned until the end state 400 is reached, as shown in FIGS. 10 and 11. In the end state 400, the needle 92 is once more folly encased by the sleeve 20. hi the end state 400, the tab 60 is in the slot 51, thereby allowing the sleeve 20 to be displaced distally 2 with respect to the proximal portion 65 of the barrel 30 when compared to the initial state 100. When the sleeve 20 is displaced distally 2, the snap fit provisions 53, 63 are able to engage, thereby locking the sleeve 20 with the barrel 30. In a preferred embodiment, the syringe 90 comprises a pre-loaded cartridge 96 filled with a substance for injection and the safety guard 10 further comprises the needle 92. The needle 92 is attached to the barrel 30 and has a free proximal end 94 for insertion into the pre-loaded cartridge 96 when the barrel 30 is attached to the syringe 90, such that the needle 92 is stationary with respect to the syringe 90 once it is inserted into the pre-loaded cartridge 96. By providing a pre-loaded cartridge 96 and a fixed needle 92, changing of needles between loading the syringe 90 and injecting the patient is thus avoided, thereby reducing needle stick risk.

Whilst there has been described in the foregoing description exemplary embodiments of the present invention, it will be understood by those skilled in the technology concerned that many variations in details of design, construction and/or operation may be made without departing from the present invention. For example, the barrel 30 may be of a single piece instead of comprising two separable sections. The barrel 30 may be at least partially disposed in the sleeve 20 instead of the sleeve 20 being disposed in the barrel 30 as shown in the figures. To prevent locking of the sleeve 20 with the barrel 30 prior to use of the needle 92, the stopper 70 may comprise the projection 50 on the sleeve 20 being a tab while the projection 60 on the barrel 30 is a ring. Moreover, instead of a ring and a tab, the projection 50 on the sleeve 20 and the projection 60 on the barrel 30 could both be tabs initially aligned to act against each other before use of the needle 92, whereby rotation of the sleeve 20 to the return state 300 results in the tabs no longer being aligned to act against each other, thereby allowing rotation 7 or distal 2 sliding of the sleeve 20 with respect to the barrel 30 until the snap fit provisions 53,63 engage and lock the sleeve 20 with the barrel 30. The stopper 70 may comprise more than one projection 50 on the sleeve 20 and more than one projection 60 on the barrel 30. The snap fit provisions 53,63 could be disposed on the sleeve 20 and the barrel 30 such that in the end state 400, the sleeve 20 is not more distal 2 with respect to the barrel 30 than when in the initial state 100 in order for the snap fit provisions 53,63 to engage and lock the sleeve 20 with the barrel 30.

Claims

The Claims

1. A safety guard for a syringe needle, the safety guard comprising: a barrel for releasably attaching the safety guard to a syringe; a sleeve for encasing the needle, the sleeve being configured for slidable, rotatable and lockable engagement with the barrel; a resilient element for biasing the sleeve distally and rotationally with respect to the barrel; and a stopper to prevent locking of the sleeve with the barrel prior to use of the needle, wherein the sleeve is configured to rotate to a return state in anticipation of locking with the barrel after use of the needle.

2. The safety guard of claim 1, further comprising snap fit provisions on the sleeve and the barrel such that the sleeve locks with the barrel by engagement of the snap fit provisions to prevent proximal movement of the sleeve with respect to the barrel.

3. The safety guard of claim 2, wherein the snap fit provisions comprise at least one cantilever snap on the sleeve and a corresponding hole in the barrel.

4. The safety guard of claim 2 or claim 3, wherein the stopper comprises a projection on the barrel and a projection on the sleeve configured to act against each other to prevent movement of the sleeve with respect to the barrel, thereby preventing engagement of the snap fit provisions.

5. The safety guard of claim 4, wherein the projection on the sleeve and the projection on the barrel comprise a ring and a tab.

6. The safety guard of claim 5, wherein the ring comprises a slot for allowing passage of the tab therethrough to allow engagement of the snap fit provisions, the slot being positioned on the ring such that the tab axially aligns with the slot only after rotation of the sleeve to the return state.

7. The safety guard of any one of claims 4 to 6, wherein one of the projection on the sleeve and the projection on the barrel include a notch for rotationally acting against the other of the projection on the sleeve and the projection on the barrel, so as to prevent rotation of the sleeve prior to use of the needle.

8. The safety guard of any one of the preceding claims, wherein the barrel comprises a first section for engaging the sleeve and a second section for attachment to the syringe, the first section and second section being separable.

9. The safety guard of any one of the preceding claims, wherein the syringe comprises a pre-loaded cartridge and the safety guard further comprises the needle, the needle being attached to the barrel and having a free proximal end for insertion into the preloaded cartridge when the barrel is attached to the syringe, the needle further being stationary with respect to the syringe when inserted into the preloaded cartridge.

10. A syringe assembly comprising a syringe, a needle and a safety guard, the safety guard comprising: a barrel for releasably attaching the safety guard to the syringe; a sleeve for encasing the needle, the sleeve being configured for slidable, rotatable and lockable engagement with the barrel; a resilient element for biasing the sleeve distally and rotationally with respect to the barrel; and a stopper to prevent locking of the sleeve with the barrel prior to use of the needle, wherein the sleeve is configured to rotate to a return state in anticipation of locking with the barrel after use of the needle.

11. The syringe assembly of claim 10, further comprising snap fit provisions on the sleeve and the barrel such that the sleeve locks with the barrel by engagement of the snap fit provisions to prevent proximal movement of the sleeve with respect to the barrel.

12. The syringe assembly of claim 11, wherein the snap fit provisions comprise at least one cantilever snap on the sleeve and a corresponding hole in the barrel.

13. The syringe assembly of claim 11 or claim 12, wherein the stopper comprises a projection on the barrel and a projection on the sleeve configured to act against each other to prevent movement of the sleeve with respect to the barrel, thereby preventing engagement of the snap fit provisions.

14. The syringe assembly of claim 13, wherein the projection on the sleeve and the projection on the barrel comprise a ring and a tab.

15. The syringe assembly of claim 14, wherein the ring comprises a slot for allowing passage of the tab therethrough to allow engagement of the snap fit provisions, the slot being positioned on the ring such that the tab axially aligns with the slot only after rotation of the sleeve to the return state.

16. The syringe assembly of any one of claims 13 to 15, wherein one of the projection on the sleeve and the projection on the barrel include a notch for rotationally acting against the other of the projection on the sleeve and the projection on the barrel, so as to prevent rotation of the sleeve prior to use of the needle.

17. The syringe assembly of any one of claims 10 to 16, wherein the barrel comprises a first section for engaging the sleeve and a second section for attachment to the syringe, the first section and second section being separable.

18. The syringe assembly of any one of claims 10 to 17, wherein the syringe comprises a pre-loaded cartridge and the needle is attached to the barrel, and wherein the needle has a free proximal end for insertion into the pre-loaded cartridge when the barrel is attached to the syringe, the needle further being stationary with respect to the syringe when inserted into the preloaded cartridge.