Abstract: A syringe (10) has a plunger (20), a barrel (11) and a collar (40, 50) with two pawls (42A, 42B). The plunger has two opposed ratchets (23A, 23B) that align with the one each of the pawls and thereby or impede, withdrawal of the plunger during or following depression of the plunger. The barrel has a collar with an inner (50) and an outer member (40) that are incapable of rotation relative with respect to each other. The outer member has the two pawls (42A, 42B) and two fingers that slidably engage opposed guide slots (28) on the plunger to thereby prevent or minimize rotation of the plunger relative to the collar. The inner member of the collar is operable to prevent engagement of the plunger ratchet by the two pawls until the plunger is depressed.

Abstract: A syringe is provided which comprises a barrel (11) and a needle sheath (30) slidably located within the barrel, a plunger (20) with a plunger seal (23), a needle, a needle sheath (30) and a sheath seal (50), arranged so that depression of the plunger forces the needle sheath to move into a position where it covers or at least partly encloses the needle after delivery of fluid contents of the syringe. The needle sheath may be manually actuated or may be actuated by decompression of a spring. The syringe may further comprise a plunger disabling means operable to impede, prevent or otherwise hinder withdrawal of the plunger during or following depression of the plunger. The syringe may be a pre-filled syringe or a syringe which is filled by a user.

Abstract: A single use retractable syringe (1) comprises a hollow barrel (2), a needle (3) engaged with a first end (4) of the hollow barrel (2) and a plunger (5) slideably disposed in the hollow barrel (2). Corresponding interlocking portions (6,7) are provided on the plunger (5) and needle (3) and are engageable only when radially aligned. The syringe (1) is provided with means for rotating the plunger (5) relative to the needle (3) from an orientation where the corresponding interlocking portions (6,7) are radially non-aligned on an initial depression of the plunger (5) toward the hollow barrel first end (4) to expel air to an orientation where the corresponding interlocking portions (6,7) are radially aligned on a subsequent depression of the plunger (5) to dispense fluid from the hollow barrel (2), thereby enabling the corresponding interlocking portions (6,7) to engage and retract the needle (3) into the hollow barrel (2) on a subsequent retraction of the plunger (5) away from the first end (4) following use.