Safety syringe

1 . A safety syringe comprising:

a barrel having an opening at an end thereof;

a bung positioned in the barrel and creating a volume between the opening and the bung;

a handle portion, having an aperture, secured to the barrel;

a syringe plunger slidably engaged with the handle portion and 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,

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; and

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,

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.

2 . The safety syringe according to claim 1 , wherein the brake forms at least part of the aperture in the handle portion in which the barrel is received.

3 . The safety syringe according to claim 2 , wherein the brake forms at least part of an inner circumference of the aperture.

4 . The safety syringe according to claim 2 , wherein the barrel is received within the aperture such that an interference fit is formed between the barrel and the brake.

5 . The safety syringe according to claim 4 , wherein before the barrel is received within the aperture, a diameter of the aperture is greater than a diameter of the barrel of the syringe,

and wherein the brake is engageable upon receipt of the barrel within the aperture.

6 . The safety syringe according to claim 5 , wherein the handle portion is operable to open the aperture,

and is further operable to close the aperture after insertion of the barrel within the aperture to engage the brake wherein the handle portion comprises two portions, separable to open the aperture wherein the two portions are connected by a hinge.

7 . The safety syringe according to claim 1 , wherein the handle portion comprises the reaction surface which is configured to compress and/or laterally move the grommet on application of an axial force on the grommet with respect to the handle portion wherein the reaction surface is angled to displace the grommet laterally inwards on axial movement of the grommet with respect to the handle portion wherein the reaction surface is configured to resist axial movement of the grommet with respect to the handle portion, such that the axial force on the grommet compresses and/or laterally expands the grommet.

8 . The safety syringe according to claim 7 , wherein a rearward surface of the grommet is configured to contact a flange of the barrel when the barrel is received in the aperture wherein the rearward surface extends from a rearward end of the aperture.

9 . The safety syringe according to claim 8 , wherein the handle portion comprises a bottom out face configured to contact the flange of the barrel upon receipt of the barrel within the aperture for preventing forward movement of the barrel.

10 . The safety syringe according to claim 1 , further comprising an insert fittable to the handle portion and configured to engage the brake.

11 . The safety syringe according to claim 10 , wherein the insert comprises one or more lateral displacement features configured to interact with the grommet to displace the grommet laterally inwards.

12 . The safety syringe according to claim 10 , wherein the brake is in contact with a rearward surface of the barrel.

13 . The safety syringe according to claim 12 , wherein the insert is configured to hold the brake in compression against the rearward surface of the barrel.

14 . The safety syringe according to claim 1 , further comprising:

a safety plunger longitudinally coupled to the syringe plunger such that an inward stroke of the safety plunger causes the inward stroke of the syringe plunger; and

a sheath directly or indirectly slidably engaged with the handle portion and configured to cover at least partially the opening in the barrel,

wherein the safety plunger is configured to longitudinally couple to the sheath at a first point on the inward stroke and is configured to longitudinally decouple from the syringe plunger at a second point on the inward stroke such that the safety plunger is longitudinally moveable independently of the syringe plunger,

and wherein further movement of the safety plunger after longitudinally decoupling causes the sheath to at least partially cover the opening in the barrel wherein, prior to operation of the safety syringe, the safety plunger is longitudinally decoupled from the sheath and configured to longitudinally couple to the sheath at the first point on the inward stroke wherein the rotational force is applied to the barrel after longitudinal decoupling of the safety plunger and the syringe plunger wherein the rotation mechanism comprises a first screw thread on the safety plunger and a second screw thread on the syringe plunger and configured to engaged with the first screw thread to rotate the syringe plunger on movement of the safety plunger after longitudinal decoupling wherein the rotation mechanism is further configured to control a rate of travel of the safety plunger after longitudinal decoupling.

15 . The safety syringe of claim 1 , wherein the reaction surface is a first reaction surface, and

wherein an outer sidewall of the grommet rests against a second reaction surface, transverse to the first reaction surface, inhibiting radially outward movement of the grommet, such that the grommet is configured to contact the sidewall of the barrel.

16 . 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.

17 . 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.

18 . The kit of parts according to claim 17 , further comprising:

a safety plunger configured to be longitudinally coupled to the syringe plunger such that an inward stroke of the safety plunger causes the inward stroke of the syringe plunger; and

a sheath configured to cover at least partially the opening in the barrel,

wherein the safety plunger is configured to longitudinally couple to the sheath at a first point on the inward stroke and is configured to longitudinally decouple from the syringe plunger at a second point on the inward stroke such that the safety plunger is longitudinally moveable independently of the syringe plunger, and

wherein further movement of the safety plunger after longitudinal decoupling causes the sheath to at least partially cover the opening in the barrel.