Safety syringe

A safety syringe apparatus for use with a syringe comprising a barrel having an opening at an end thereof and a bung positioned in the barrel and creating a volume between the opening and the bung, the syringe apparatus comprising:

• a handle portion, having an aperture, for securing to the barrel;
• a syringe plunger slidably engaged with the handle portion and configured, when the handle portion is secured to the barrel, to be moveable within the barrel on an inward stroke to drive the bung forwards within the barrel to cause a substance within the volume to be expelled from the opening;
• a rotation mechanism configured to rotate the syringe plunger within the barrel at a point during the inward stroke when the syringe plunger is in contact with the bung, such that a rotational force is applied to the barrel;
• and
• a brake comprising a compressible material connected to the handle portion and configured to provide a frictional force to resist the rotational force applied to the barrel,
• wherein the handle portion is configured to hold the compressible material of the brake in compression directly against an outer portion of the barrel, where the brake is an elastomeric grommet arranged around the barrel;
• wherein the brake is an elastomeric grommet arranged around a sidewall of the barrel;
• wherein an inner diameter of the elastomeric grommet is larger than an outer diameter of the sidewall of the barrel;
• wherein the grommet rests against a reaction surface at a forward end of the grommet, wherein the reaction surface is transverse to an axial direction of the safety syringe;
• wherein a portion of the grommet stands proud of the aperture, extends longitudinally away from the aperture in a rearward direction, and is configured to interact with a flange of the barrel and the handle portion to engage the brake by compression of the portion of the grommet standing proud of the aperture between the flange of the barrel and the handle portion;
• and
• wherein a clearance exists between the sidewall of the barrel and an inner sidewall of the grommet during insertion of the barrel into the handle portion.

A kit of parts for forming a safety syringe apparatus for use with a syringe comprising a barrel having an opening at an end thereof and a bung positioned in the barrel and creating a volume between the opening and the bung, the kit of parts comprising:

• a handle portion, having an aperture, for securing to the barrel;
• a syringe plunger for slidable engagement with the handle portion and configured, when the handle portion is secured to the barrel, to be moveable within the barrel on an inward stroke to drive the bung forwards within the barrel to cause a substance within the volume to be expelled from the opening;
• a rotation mechanism configured to rotate the syringe plunger within the barrel at a point during the inward stroke when the syringe plunger is in contact with the bung, such that a rotational force is applied to the barrel;
• and
• a brake comprising a compressible material connectable to the handle portion and configured to provide a frictional force to resist the rotational force applied to the barrel wherein the handle portion is configured, when secured to the barrel, to hold the compressible material of the brake in compression directly against an outer portion of the barrel, where the brake is an elastomeric grommet arranged around the barrel
• wherein the brake is an elastomeric grommet arranged around a sidewall of the barrel;
• wherein an inner diameter of the elastomeric grommet is larger than an outer diameter of the sidewall of the barrel;
• wherein the grommet rests against a reaction surface at a forward end of the grommet, wherein the reaction surface is transverse to an axial direction of the safety syringe;
• wherein a portion of the grommet stands proud of the aperture, extends longitudinally away from the aperture in a rearward direction, and is configured to interact with a flange of the barrel and the handle portion to engage the brake by compression of the portion of the grommet standing proud of the aperture between the flange of the barrel and the handle portion;
• and
• wherein a clearance exists between the sidewall of the barrel and an inner sidewall of the grommet during insertion of the barrel into the handle portion.