GB2508490A

GB2508490A - A sharps retraction device

Info

Publication number: GB2508490A
Application number: GB1317381.0A
Authority: GB
Inventors: Philip Arnold Brown; Allen John Pearson; James Terence Collins
Original assignee: C Major Ltd
Current assignee: C Major Ltd
Priority date: 2011-12-06
Filing date: 2011-12-06
Publication date: 2014-06-04
Anticipated expiration: 2031-12-06
Also published as: GB2508490B; GB201317381D0

Abstract

A device 10 for retaining a medical sharp 18 having a hollow housing with proximal and distal ends, a connector 16 in the distal end for receiving a medical sharp 18, and a retraction mechanism. The retraction mechanism is movable between a first position in which the sharp 18 protrudes from the distal end of the housing and is available for use and a second position in which the connector 16 and any sharp 18 received therein are completely retracted into the housing. The device 10 further comprises an actuator to operate the retraction mechanism and allow movement from the first position to the second position. A port is located in the housing and a closure device 64 is operable upon retraction of the connector 16 into the housing to close the port. An accessory 84 connects a fluid conduit 82 to the port for supplying or receiving fluids.

Description

A SHARPS RETRACTION DEVICE

The present invention relates to an apparatus for retracting medical sharps after use in medical procedures.

The term "sharps" is well known in the medical field, and is used herein, to mean needles and any other instruments with points, blades, cutting edges etc. which are potentially hazardous.

In the often high pressure conditions of medical and nursing work, the accidental puncture or scratch with a needle, or other sharp object, and the consequent risk of infection with, for example, HIV or hepatitis, is becoming increasingly hazardous to the professions and potentially more costly to health authorities. Therefore there is the need to provide a means for isolating sharps after use such to minimise subsequent injury or infection.

An attempt to address this problem is shown in GB 2341804 which discloses an example mechanism which uses a spring for retracting a needle into the syringe barrel.

Numerous other examples are also known.

Other prior art uses complex setups in specific

applications to provide retractable needles. These setups however, as well as being fiddly to use, are expensive and therefore unsuitable in the context of single use disposable s.

According to the present invention there is provided a device for retaining a medical sharp comprising a hollow housing with proximal and distal ends, a connector in the distal end of the housing for receiving a medical sharp, a retraction mechanism movable between a first position in which the sharp protrudes from the distal end of the housing and is available for use and a second position in which the connector and any sharp received therein are completely retracted into the housing, and an actuator to operate the retraction mechanism and allow movement from the first position to the second position, wherein a port is located in the housing and the connector includes a fluid channel for communicating between the port and a sharp connected to the connector, and further comprising an accessory connectable to the housing and operable to pass fluid through the port into the fluid channel or to receive fluid through the port from the fluid channel, the device further comprising a closure device operable upon retraction of the connector into the housing to close the port.

Thus the present invention provides a simple device for automatically retracting a sharp after use which has reduced complexity and cost and is simple to operate.

In one embodiment, the accessory defines a fluid chamber connectable to the port and a plunger moveable in the chamber to drive fluid from the chamber to the port or to suck fluid from the port into the chamber, wherein the plunger is co-operable with the actuator to cause retraction of the connector into the housing.

In an alternative embodiment, the accessory comprises a fluid conduit having a first end connectable to the port in the housing and a second end connectable to a means to deliver fluid through the conduit to the port or to withdraw fluid from the port through the conduit.

Thus the device may be combined with an accessory to create a delivery or aspiration device. In one form the combination forms a syringe. In this case accessories of different sizes, to provide different volumes of medicament, can be provided, each of which can be combined with the same device for retaining the sharp. Therefore an inventory of parts for forming syringes of differing sizes can be maintained at reduced cost. In another form the device can be connected to other fluid delivery or removal systems, such as dialysis equipment.

The retraction mechanism may comprise a detent to hold the connector in the first position and spring means biased into an energy-storing state, wherein the actuator is operable to release the detent and the spring means, whereby the spring means releases energy to move the connector into the housing.

The detent may comprise a projection releasably engageable in a corresponding recess in the housing.

The spring means may be a torsion spring located between the connector and the retraction mechanism.

The actuator may comprise a hollow cylinder slideably received over the housing, having an open distal end within which the housing is located and a closed proximal end, wherein the actuator is slidable over the housing in order to release the detent.

The internal wall of the hollow housing may define a helical path for the retraction mechanism to engage with.

The retraction mechanism may also be rotatably mounted on the connector.

The internal wall of the housing may also define an axial slot and the connector may further comprise a projection, such that as the retraction mechanism moves along the helical path it rotates relative to the connector and the connector moves axially but does not rotate.

The pitch of the helical path may vary along its length.

The pitch may also be smaller at each end of the path and larger therebetween.

The helical path may also comprise a helical groove.

The connector may be in particular a Luer lock connector.

The invention will now be described in detail, by way of example only, with reference to the accompanying drawings, in which: Figures 1A -1D show views of a medical instrument comprising a sharps retraction device according to a first embodiment of the present invention connected to a fluid dispensing device wherein: Figure 1A shows a side view of the medical instrument in an unused state; Figure lB shows a side view of the medical instrument in the used state; Figure lC shows an exploded perspective view of the sharps retraction device and the fluid dispensing device; Figure 1D shows a perspective view of the sharps retraction device and the fluid dispensing device as assembled.

Figures 2A-2D show cross section views of the sharps retraction device according to the present invention at different stages of its operation.

Figures 3A -3D show views of a medical instrument comprising the sharps retraction device according to the present invention connected to an alternative fluid dispensing device wherein: Figure 3A shows a side view of the medical instrument in an unused state; Figure 3B shows a side view of the medical instrument in the used state; Figure 3C shows an exploded perspective view of the sharps retraction device and the alternative fluid dispensing device; Figure 3D shows a perspective view of the sharps retraction device and the alternative fluid dispensing device as assembled.

Figures 4A and 4B show isometric views of the sharps retraction device according to the present invention when used with alternative ancillary equipment such a connector tube, in both unconnected and connected states respectively.

Figure 5 is a perspective view of an alternative medical instrument comprising a sharps retraction device in accordance with a second embodiment of the present invention and connected to a fluid dispensing device.

Figures 6A-6D show cross section views of the sharps retraction device of figure 5 at different stages of its operation.

Figures 7A -7C show cross section views of the sharps retraction device of figure 5 when connected to fluid dispensing devices of different volumes.

Figures SA and SB show perspective views of an alternative medical instrument comprising a sharps retraction device of the present invention also housing a safety feature to prevent accidental triggering. Figure 8A shows the instrument in the locked position and figure SB in the unlocked position.

Figures 1A -1C show a first embodiment of a sharps retraction device 10 of the present invention in combination with a fluid dispensing device 12. The sharps retraction device 10 includes a casing 11, an actuation mechanism 14, a Luer lock assembly 16 and a sharp 18, in particular a needle. The fluid dispensing device 12 defines a fluid chamber 22, a fluid delivery channel 24 located at the proximal end, and a plunger 26 together with a plunger cap 28. The purpose of the fluid channel 24 is to allow fluid transfer between the fluid chamber 22 and the sharp 18.

Although not visible in the figures, for reference purposes, the fluid delivery channel 24 has been shown in figure 1C as a dotted line.

Together the sharps retraction device 10 and fluid dispensing device 12 form a syringe 30 for administering medicament to a patient.

In the following description and figures, the distal end shall refer to the end of the retraction device 10 which houses the sharp 18 and is shown in the figures on the left hand side. The proximal end is remote from the sharp 18, and is the end closest to the operator and is on the right hand side in the figures.

Figure 2A-2D show cross sections of the sharps retraction device 10. The casing 11 of the retraction device is a hollow, generally cylindrical, casing open at both proximal and distal ends. A spiral groove 36 is formed in the inner surface of the proximal portion of the casing 11.

The pitch of the spiral groove 36 is varied along the length of the casing 11.

Also inside the cylindrical casing 11 is an anti rotation feature 38 which comprises an axial slot which extends between the proximal and distal ends of the casing 11 but not along its full length.

A radial side channel 40 near the distal end 34 of the casing 11 forms an opening into the interior of the casing 11. A further opening 44 passes through the casing 11 at the distal end of the spiral groove 36.

A hollow retraction sleeve 46 is slidably received over the proximal end of the casing 11. The retraction sleeve 46 comprises a closed proximal end 48, thus forming an actuation surface 50. The distal end 52 of the retraction sleeve 46 is open to receive the casing 11.

The Luer lock assembly 16 is slidably received in the distal end 34 of the casing 11. The Luer lock assembly 16 has at its distal end a standard Luer lock connector 54 to receive a hollow needle or other medical sharp. The Luer lock assembly 16 contains a radial channel 55 and an axial channel 56. when the Luer lock assembly 16 is mounted in the casing 11, the channels 55 and 56 form a fluid path which connects the casing side channel 40 with the needle. 0-rings 58;60 isolate the fluid path 56 to prevent fluid leakage into the casing 11.

Toward the proximal end of the assembly 16 is a radially protruding shoulder 62 which is configured to sit in the slot of the anti rotation feature 38.

Inside the distal end of the casing 11 and surrounding part of the Luer lock assembly 16 is a circumferential collar 64, which is held in place by a raised ridge 66 formed on the Luer lock assembly 16. The collar 64 comprises a rim 68 at its distal end, which extends radially outwardly.

A retraction rate controller 70 is located at the proximal end of the Luer lock assembly 16. The controller 70 is essentially a disc rotatably mounted on a shaft protruding from the proximal end of the casing 11. The controller 70 has at its proximal end a pin 72 for engagement with the spiral groove 36 of the casing 11. A rotation lock 74, with head 76, is connected to the retraction rate controller 70. The lock 74 is movable radially and biased outwardly so that initially it locates in opening 44, thereby preventing rotation of the controller 70.

Connecting the Luer lock assembly 16 to retraction rate controller 70 is a torsion spring 78. The spring 78 connects to the proximal face of the Luer lock assembly 16 and also to the distal face of the retraction rate controller 70. The spring 78 is held in torsion by the lock 74, which is initially located in opening 44.

In a starting position of the sharps retraction device 10, the Luer lock assembly 16 rests at the distal end of casing 11 as shown in figure 2A, locked in place by the engagement of rotation lock 74 in the opening 44. A sharp 18 such as a needle as shown may be attached to the standard Luer lock connector by medical personnel when required. In this position, the head 76 of the rotation lock 74 extends beyond the outer diameter of the casing 11. By pushing the retraction sleeve 46 towards the distal end of the retraction device 10, the sleeve 46 comes into contact with the head 76 of the rotation lock 74, causing the rotation lock 74 to be depressed radially inwardly inside the casing 11, as shown in figure 2B. Once the rotation lock 74 is -10 -depressed radially inwardly, the tension in torsion spring 78 is released, causing the retraction rate controller 70 to rotate. As pin 72 engages in groove 36, rotation of controller 70 causes pin 72 to travel along the spiral groove 36 towards the proximal end of the casing 11, as shown in figure 2C.

Movement of the retraction rate controller 70 along the spiral groove 36 also causes the entire Luer lock assembly 16 to move, due to the physical connection of the Luer lock assembly 16 with the retraction rate controller 70. As the Luer lock assembly 16 retracts, it does not rotate. Instead, the Luer lock assembly 16 is guided without rotation towards the proximal end of the casing 11 by engagement of shoulder 62 in the slot of the anti rotation feature 38. As the Luer lock assembly 16 is connected to the sharp 18, the retraction of the Luer lock assembly 16 also causes the sharp 18 to be retracted into the casing 11.

Progression of the Luer lock assembly 16 and retraction rate controller 70 towards the proximal end of casing 11 continues until either the tension in torsion spring 78 is relieved (due to the relative twisting motion of the retraction rate controller with the Luer lock assembly), or until the shoulder 62 has progressed along the total length of the anti rotation feature 38. As shown in figure 2D, the retraction range must be enough to ensure that the sharp 18 is completely within the casing 11.

The retraction rate of the Luer-lock assembly 16 into the casing 11 is controlled by the interaction between the pin 72 of the retraction rate controller 70 and the spiral -11 -groove 36. During the retraction motion, the pin 72 is forced to follow the profile dictated by the spiral groove 36. In situations where a rapid retraction rate is required, a pitch L of the spiral 36 may be made large. Conversely, in situations where a slower retraction rate is required, the pitch L of spiral 36 may be decreased. By varying the pitch L over the working range of the retraction device 10, a retraction rate withdrawal profile can be generated, wherein the retraction rate of the Luer lock assembly 16 can vary depending on its position along the spiral 36.

By being able to control the retraction speed of the Luer lock assembly 16, this allows better control over how the sharp 18 is removed from a patient. Specifically, by reducing jerk in the sharp's removal, this eliminates spluttering, that is the escape of fluid from the sharp during its retraction and minimises the risk of injury to the patient caused by the sharp's removal.

In use, the fluid dispensing device 12 is connected to the sharps retraction device 10 to create a syringe 30 by passing the proximal end of the sharps retraction device 10 through the distal end of the fluid dispensing device 12. A suitable snap fit between the two devices causes them to lock together in a piggy back style arrangement, as shown in figures 1A -1D. In the located position, the side channels 24;40 from both devices 12;l0 communicate to form a passage for fluid transfer between the fluid chamber 22 and the sharp 18. Further, in the located position, the plunger cap 28 from plunger 26 overlaps with the actuation surface 50 at the distal end of sleeve 46.

-12 -To administer fluid from the fluid chamber 22 to the sharp 18, initially the plunger 26 is positioned in an extended proximal position, as shown in figure 1A. On depression of the plunger 26 towards the distal end of the fluid dispensing device 12, fluid in the fluid chamber 22 is forced through the connected passages 24;40;55;56 into the sharp 18.

Towards end of plunger stroke, the overlapping portion of plunger cap 28 comes into contact with the actuation surface 50. Continued depresGion of the plunger 26 causes movement of the retraction sleeve 46 in the distal direction over casing 11 and ultimately causes release of the rotation lock 74 and retraction of the Luer lock assembly 16 as detailed above.

To prevent further fluid escape from the fluid chamber 22 and channel 24 after retraction, the collar 64 is provided to block side channel 40.

In use, as the Luer lock assembly 16 is retracted into the casing 11, the ridge 66 formed on the Luer lock assembly 16 comes into contact with the collar 64. This forces the collar 64 to move proximally together with the Luer lock assembly 16. The collar 64 moves with the Luer lock assembly 16 until the rim 68 comes into contact with casing 11. Once the rim 68 abuts the casing 11 the collar 64 seals off passage 40 to prevent any remaining fluid from escaping from channel 24 and chamber 22. Once the collar 64 has abutted casing 11, the ridge 66, forced by the restoring force in the spring 78, deforms underneath rim 68. Having deformed -13 -round rim 68, the Luer lock assembly 16 then continues to move unobstructed into the retraction casing 11.

In some applications, a user may wish to retract the Luer lock assembly 16 before the plunger 26 has proceeded fully through its working range to contact actuation surface 50. Alternatively, in situations where the instrument is used for aspiration as opposed to injection, as the plunger 26 is pulled proximally it will never engage with the actuation surface 50. In these cases, a separate means to initiate retraction of the Luer lock assembly 16 and sharp 18 is required. In this case, the retraction device 10 may be designed to allow manual engagement of the rotation lock 74 by the user such to trigger the retraction motion.

It will be seen that the advantage of the above setup is that it allows sharps to be isolated after use. This helps to minimise any subsequent injury or infection caused by exposed sharps. Furthermore, by controlling how the sharp is retracted using a helical path, fluid escape during retraction of any sharp can be eliminated.

Figures 3A -3C show an alternative fluid dispensing device 80, comprising a larger fluid chamber 22. It will be appreciated therefore that the same retraction device 10 can be combined with different fluid dispensing devices 12;80 to provide syringes 30 for delivering different amounts of medicament.

In any of the fluid dispensing devices 12;80, it is apparent that the device need not be opaque. In some instances, the fluid dispensing device l2;80 may be -14 -transparent to allow viewing of the fluid chamber 22 located in the device. Markings may be also present on the device so as to allow volumetric measurement of the fluid located inside the fluid chamber 22.

As shown in figures 4A and 4B, in other embodiments the retraction device 10 may be connected to ancillary equipment other than a fluid dispensing device l2;80. For example, a detachable connector tube 82 may be provided. This configuration may be used in situations where the retraction device 10 is used for aspiration, as opposed to injection.

Alternatively, this setup may be used where fluid is required to be delivered or extracted by a medical machine, for example a dialysis machine. The tube 82 comprises two ends, the first end being suitable for attachment to the retraction device 10 and the second end suitable for attachment to medical fluid containers or delivery systems.

A guide collar 84 is located at the first end of the tube 82. The collar 84 attaches with the retraction device 10 e.g. by snap fit engagement around casing 11, to provide a sealed fluid connection between the tube 82 and the side channel 40 of the retraction device 10, as shown in figure 4B. Any suitable connection means may be provided at the second end of the tube to allow connection of the tube with any medical fluid containers or delivery systems. Fluid may be delivered to the needle 18 via the tube 82, or fluid may be withdrawn from the patient through the needle 18 and passed into the tube 82. Thereafter, the retraction device 14 may be operated, for example by manual pressure on the actuation surface 50, to retract the needle 18 and the Luer lock assembly 16 in the casing 11.

-15 -Figure 5 shows another medical instrument comprising a second embodiment of a sharps retraction device 110 in combination with a fluid dispensing device 112. As with the first embodiment, the sharps retraction device includes a casing 111, a Luer lock assembly 116 including a standard Luer lock connector for attaching a sharp 118, such as a needle. The fluid dispensing device 112 includes a body defining a fluid chamber 122, and a plunger 126.

Together the sharps retraction device 110 and fluid dispensing device 112 form a syringe 130 for administering medicament to a patient.

Figures GA -GD show cross sections of the sharps retraction device 110 at various stages of operation. The body of the retraction device 110 is a hollow, generally cylindrical casing 111, open at both proximal and distal ends.

A side channel 140 near the distal end of the casing 111 forms an opening into the interior of the retraction device 110.

A hollow retraction housing 190 is slidably received in the casing 111 and protrudes from the proximal end of the casing 111. The retraction housing 190 comprises a closed proximal end, thereon forming an actuation surface 191. The distal end of the retraction housing 190 is open.

The Luer lock assembly 116 is slidably received in the distal end of the main casing 111. The Luer lock assembly 116 has at its distal end a standard Luer lock connector to -16 -receive a hollow needle or other medical sharp 118. When the Luer lock assembly 116 is mounted in the casing 111, a fluid path 156 connects the casing side channel 140 with the sharp 118. The proximal portion of the Luer lock assembly 116 is generally cylindrical but split into a plurality of resilient short and long legs l92;193. Short legs 192 extend substantially parallel to the axial direction of the retraction device 110 and further comprise, at their proximal ends, a radially outward extending flange 194. Long legs 193 are biased in a radially inward direction and further comprise, at their proximal ends, a radially outward and radially inward extending flange 194A.

Circumferentially around the legs 192;193 is a spring 195, which is held in compression axially between a shoulder 196 in the casing 111 and the radially outward flange 194 of the short legs 192.

A bridging member 197 is located between the retraction housing 190 and the Luer lock assembly 116. The bridging member 197 comprises a head 198 comprising a frusto-conical portion 199 and a cylindrical portion 200, a reduced diameter neck 201 and a plurality of resilient arms 202.

Each arm 202 has a shoulder 203 which engages with the open end of the retraction housing 190.

In a starting position of the sharps retraction device 110, as shown in figure GA, the radially outward portion of the flange 194A of long legs 193 rest against the cylindrical portion 200 of the enlarged head 198. Thus the long legs 193 are deflected radially outwardly by the head 198 of the bridging member 197 to extend substantially -17 -parallel to the short legs 192. The radially outward portion of the flange 194A of long legs 193 engages with holes 204 spaced around the circumference of casing 111. Thus the Luer lock connector 116 is locked in position at the distal end of the casing 111.

By pushing the actuation surface 191, the retraction housing 190 moves distally into the casing 111. The bridging member 197 is also moved distally relative to the Luer lock assembly 116. This relative motion causes the head 198 of bridging member 197 to move past the flange 194A of long legs 193, causing the long legs 193 to snap inwardly onto the neck portion 201 of the bridging member 197 as shown in figure GB. Thus the radially outward portions of the flange 194A from long legs 193 disengage from holes 204 in casing 111. Continued pushing of the retraction housing 190 causes the arms 202 of bridging member 197 to deflect inwardly as shown in figure GC, due to contact with projection 205 which extends in the proximal direction from short legs 192. This inward deflection causes the bridging member 197 to disengage from the distal end of the retraction housing 190.

The spring 195 is then free to extend. In extending, the spring 195 pushes the connected Luer lock assembly 116 and bridging member 197 proximally into the retraction housing 190. As the Luer lock assembly 116 is connected to the sharp 118, the extension of the spring also causes the sharp 118 to be retracted into the retraction housing 190 to the final position as shown in figure GD.

Figure 7 shows in more detail the cross section of the fluid dispensing device 112 and how it interconnects with the sharps retraction device 110 to form a syringe. At its -18 -distal end, the fluid dispensing device 112 has a side channel 124 which connects the fluid chamber 122 to the Luer lock assembly 116 in use. A flange 207 is formed at the proximal end of plunger 126.

In use, the fluid dispensing device 112 is connected to the sharps retraction device 110 by passing the proximal end of the fluid dispensing device 112 over the distal end of the sharps retraction device 110. Wings 208 from the fluid dispensing device 112 snap fit on to casing 111 to lock both devices 1l0;112 together.

In the located position, the side channels 140;124 of both devices l10;112 communicate to form a passage for fluid transfer between the fluid chamber 122 and the sharp 118.

Further, in the located position, the flange 207 of the plunger 126 overlaps with the actuation surface 191 of the retraction device 110.

To administer fluid from the fluid chamber 122 to the sharp 118, initially the plunger 126 is positioned in an extended proximal position. On depression of the plunger 126 towards the distal end of the fluid dispensing device 112, fluid in the fluid chamber 122 is forced through the connected channels 124;140 into the sharp 118. Towards the end of plunger the stroke, the overlapping portion of plunger flange 207 comes into contact with the actuation surface 191. Continued depression of the plunger 126 thereby forces the retraction housing 190 in the distal direction into the casing 111, and ultimately, causes release of the -19 -spring 195 and retraction of the Luer lock assembly 116 as detailed above.

In some applications, a user may wish to retract the Luer lock assembly 116 before the plunger 126 has proceeded fully through its working range to contact actuation surface 191. Alternatively, in situations where the instrument is used for aspiration as opposed to injection, as the plunger 26 is pulled proximally it will never engage with the actuation surface 191. In these cases, a separate means to initiate retraction of the Luer lock assembly 116 and sharp 118 is required. In this case, the user may manually depress the actuation surface 191 such to trigger the retraction motion -To prevent accidental triggering of the retraction mechanism, the retraction housing 190 may be provided with a radially extending button 209, which locates in a slot 210 formed in the casing 111. As shown in Figures GA-GD this may be part-way along the casing 111, but preferably is at the proximal end of the casing 111 as shown in figures BA and 8B. The slot 210 may be substantially L shaped. In the locked position the button 209 resides at one end of the slot 210. To unlock the device, the retraction housing 190 must be twisted relative to the casing 111 so that the button 209 is moved to the junction of the two arms of the slot 210. Thereafter the retraction housing 190 can be pushed axially into the casing 111 as the button 209 is able to move along the other arm of the slot 210 as shown in figure SB.

-20 -Although the above can be used as an illustrative guide to the present invention, it will be appreciated by those skilled in the art that variations and modifications can be made without departing from the scope of the invention as set out in the claims.

Claims

-21 -Claims 1. A device for retaining a medical sharp comprising a hollow housing with proximal and distal ends, a connector in the distal end of the housing for receiving a medical sharp, a retraction mechanism movable between a first position in which the sharp protrudes from the distal end of the housing and is available for use and a second position in which the connector and any sharp received therein are completely retracted into the housing, and an actuator to operate the retraction mechanism and allow movement from the first position to the second position, wherein a port is located in the housing and the connector includes a fluid channel for communicating between the port and a sharp connected to the connector, and further comprising an accessory connectable to the housing and operable to pass fluid through the port into the fluid channel or to receive fluid through the port from the fluid channel, the device further comprising a closure device operable upon retraction of the connector into the housing to close the port.
2. A device as claimed in claim 1, wherein the accessory comprises a fluid chamber connectable to the port and a plunger moveable in the chamber to drive fluid from the chamber to the port or to suck fluid from the port into the chamber, wherein the plunger is co-operable with the actuator to cause retraction of the connector into the housing.

-22 -
3. A device as claimed in claim 1, wherein the accessory comprises a fluid conduit having a first end connectable to the port in the housing and a second end connectable to a means to deliver fluid through the conduit to the port or to withdraw fluid from the port through the conduit.
4. A device as claimed in any preceding claim, wherein the retraction mechanism comprises a detent to hold the connector in the first position and spring means biased into an energy-storing state, wherein the actuator is operable to release the detent and the spring means, whereby the spring means releases energy to move the connector into the housing.
5. A device as claimed in claim 4, wherein the detent comprises a projection releasably engageable in a corresponding recess in the housing.
6. A device as claimed in claim 5, wherein the spring means is a torsion spring located between the connector and the retraction mechanism.
7. A device as claimed in any of claims 4-6, wherein the actuator comprises a hollow cylinder slideably received over the housing, having an open distal end within which the housing is isolated and a closed proximal end, wherein the actuator is slidable over the housing in order to release the detent.
8. A device as claimed in any preceding claim, wherein an internal wall of the hollow housing defines a helical path -23 -and the retraction mechanism engages with the helical path, and is movable along it.
9. A device as claimed in claim 8, wherein the retraction mechanism is rotatably mounted on the connector.
10. A device as claimed in claim 9, wherein the internal wall of housing also defines an axial slot and the connector further comprises a projection, such that as the retraction mechanism moves along the helical path it rotates relative to the connector and the connector moves axially but does not rotate.
11. A device as claimed in any of claim 8-10 wherein the pitch of the helical path varies along its length.
12. A device as claimed in claim 11 wherein the pitch is smaller at each end of the path and larger therebetween.
13. A device as claimed in any of claims 8-12 where the helical path comprises a helical groove.