Search

EP-3405239-B1 - SAFETY SYRINGE APPARATUS

EP3405239B1EP 3405239 B1EP3405239 B1EP 3405239B1EP-3405239-B1

Inventors

  • HOLLAND, Damian Alexander

Dates

Publication Date
20260513
Application Date
20170119

Claims (12)

  1. An apparatus for use with a syringe for providing a safety syringe, the apparatus comprising: a sheath (500) deployable for at least partially covering a needle of the syringe; a sheath deployment mechanism (508); and a sheath actuator (502) for deploying the sheath (500) by interaction with the sheath deployment mechanism (508), and the sheath actuator comprising a safety plunger (550) that is coupled to a syringe plunger (516) and configured to decouple from the syringe plunger at a sheath release point on the inward stroke, the sheath deployment mechanism further comprising a rotatable linkage (508) comprising a first thread configured to translate rotation of the linkage into linear motion of the sheath for deployment thereof, and wherein the sheath actuator (502) is configured to rotate the rotatable linkage on movement of the sheath actuator, under a force applied by the user onto the safety plunger (550) after the sheath release point, and wherein the sheath deployment mechanism comprises a second thread on the sheath (500), opposed to the first thread, and configured to interact with the first thread to translate rotational motion of the linkage (508) into linear motion of the sheath (500), wherein the sheath (500) is configured to be stationary in relation to the needle until the syringe plunger (516) reaches the sheath release point on its inward stroke, and wherein the sheath actuator (502) is configured for deployment of the sheath (500) to at least partially cover the needle on movement of the sheath actuator (502) relative to the syringe plunger (516) after the sheath release point.
  2. An apparatus according to claim 1, wherein the sheath deployment mechanism (508) comprises a threaded rod (551) extending from the safety plunger (550), wherein the second thread is located on threaded rod (551) and is configured to rotate the linkage on a continued syringe operation action by the user after the sheath release point.
  3. An apparatus according to claim 2, further comprising the syringe plunger (516), wherein the threaded rod (551) is configured to be received in a corresponding recess of the syringe plunger (516) for rotation thereof, and wherein the syringe plunger (516) is rotationally coupled to the rotatable linkage (508).
  4. An apparatus according to claim 3, and further comprising a rotation restrictor configured to prevent rotation of the syringe plunger (516) until after the sheath release point.
  5. An apparatus according to claim 4, wherein the rotation restrictor comprises features of one or more legs (552) of the safety plunger configured to interact with corresponding features of the linkage (508) for preventing rotation thereof.
  6. An apparatus according to claim 5, wherein the features of the one or more legs (552) of the safety plunger comprise a rib (553), and wherein the corresponding feature of the linkage comprises a slot configured to receive the rib.
  7. An apparatus according to claim 5, the rotation restrictor comprises a keyed guide configured to interact with the syringe plunger (516) to prevent rotation thereof.
  8. An apparatus according to claim 7, wherein the keyed guide comprises a keyed aperture through which the syringe plunger (516) passes, wherein at least part of the syringe plunger has a cross section configured not to be rotatable within the keyed aperture.
  9. A safety syringe comprising an apparatus according to any preceding claim.
  10. A kit of parts for use with a syringe for providing a safety syringe, the kit of parts comprising: the sheath, the sheath actuator, and the sheath deployment mechanism all of claim 1.
  11. A kit of parts according to claim 10 and further comprising a syringe to which the sheath, sheath deployment mechanism and sheath actuator are configured to be fitted.
  12. A kit of parts according to claim 11, wherein the syringe is prefilled with a medicament.

Description

Technical field The invention relates to safety syringes and apparatus for fitting to syringes to convert them to safety syringes. In particular embodiments, the invention relates to, but need not be limited to, passive safety syringes and associated apparatus. Background Broadly, syringes for medical use comprise a barrel having a hypodermic needle at one end and a plunger configured to move within the barrel such that an inward stroke of the plunger causes a substance contained within the barrel to be expelled from an aperture in the needle. Safety syringes typically include some form of safety mechanism to protect healthcare workers from the hypodermic needle after it has been injected into a patient. Exemplary safety syringes may include a sheath for covering the needle, or may cause the needle to retract within the barrel of the syringe. Safety syringes may be broadly split into 'active' and 'passive'. Active safety syringes typically require some action by a user of the syringe to engage the safety mechanism. Such action may be taken after removal of the needle from the patient, or may be taken during removal of the needle from the patient. Typically, the action required to engage the safety mechanism is separate from the action required to cause the inward stroke of the plunger. Passive safety syringes typically engage the safety mechanism without any specific action by the user, that is, without any action other than that usually taken to use the syringe. Document US 5562626 discloses a safety syringe having a sheath that automatically extends over the needle of the syringe after the syringe is used to administer an injection. Summary The inventors have appreciated that a safety syringe may comprise a spring-loaded safety mechanism that may be engaged by a healthcare worker after, and separate to, the inward stroke of the plunger. That is, the healthcare worker takes a separate action to engage the spring-loaded mechanism. The spring force urges a surface against the skin of the patient, thereby extracting the needle and simultaneously engaging a safety mechanism, such as a sheath. Such devices are prone to misuse as healthcare workers are known to remove the needle from the patient before engaging the safety mechanism. This exposes the healthcare worker to the needle after use and the spring-loaded action of the safety mechanism may lead to blood splatter from the needle. Other known safety syringes require the needle to be removed from the patient before the safety mechanism may be engaged. This exposes the healthcare worker to the needle after use. The invention provides an apparatus, a safety syringe and a kit of parts as set out in the accompanying claims. Brief description of drawings Figure 1 is a perspective view of an exemplary apparatus fitted to a syringe;Figures 2a-d show stages of operation of an exemplary apparatus fitted to a syringe for providing a safety syringe;Figure 3 is a perspective view of an exemplary apparatus fitted to a syringe;Figures 4a-d show stages of operation of an exemplary apparatus fitted to a syringe for providing a safety syringe;Figures 5a and 5b are perspective views of an exemplary apparatus fitted to a syringe; andFigures 6a-d show stages of operation of an exemplary apparatus fitted to a syringe for providing a safety syringe. Detailed description Generally, disclosed herein are safety syringes and apparatus for providing safety syringes, in which a sheath is deployed by a mechanism actuated by a sheath actuator. In exemplary apparatus, the sheath is extended along a length of a barrel of a syringe to cover at least partially a needle of the syringe. The sheath may be urged over the needle by a force applied by the user, typically during a syringe operation action, which involves action for normal use of the syringe. In exemplary apparatus, a force applied by the user after a sheath release point may move the sheath actuator relative to a syringe plunger and that relative movement is translated into a corresponding movement of the sheath. Accordingly, there is a continuous relationship between the relative movement of the sheath actuator and the syringe plunger and the movement of the sheath. This is distinct from an apparatus in which a sheath is deployed by release of a self-operating mechanism, e.g. by a biasing member. A sheath actuator interacts with a sheath deployment mechanism to deploy the sheath. In some arrangements, the movement of the sheath is ratioed with respect to movement of the sheath actuator such that a magnitude of movement of the sheath is greater than a magnitude of movement of the sheath actuator. The ratioed movement may be provided by the sheath deployment mechanism. Further, the sheath actuator may be configured to cause deployment of the sheath from in-line movement thereof. The term "in-line" is used to encompass longitudinal movement aligned with a longitudinal axis of the safety syringe. In-line movement may be caused by a sy