Patent ID: 6053892
Filing Date: 2000-04-25
Classification: A61M

Abstract:
A hypodermic syringe head with a tamper-evident closure for a syringe barrel (14), which has a barrel neck that is provided with an axial fluid outlet conduit and a circumferential bead (13) for anchoring the hypodermic syringe head, having an injection cannula (4), which is mounted in a cannula carrier (5) from which it protrudes on both axial ends and which is disposed in a cannula carrier guide (6) so as to be movable relative thereto, and a cannula guard cap (1) which is adjoined, via a rated breaking point, by an anchoring element (3) that solidly holds the cannula carrier guide (6) and can be affixed with elastic deformation to the circumferential bead (12) of the barrel neck, wherein the cannula guard cap (1) has axially extending ribs (1') on its inside circumference which engage corresponding ribs (8) of the cannula carrier (5) for rotationally driving it, wherein embodied on the circumference of the cannula carrier (5) are two axially symmetrical guide grooves (15) for a guide peg (16), provided in the interior of the cannula carrier guide (6), which extend with a predetermined inclination substantially in a V and open into one another on their end oriented toward the sealing disk (7), and the guide peg, in the unactuated state of the hypodermic syringe head, engages the orifice region (15'), oriented toward the sealing disk (7), of the guide grooves (15) and upon a rotation of the cannula guard cap (1) in each of the two directions of rotation slides relative to one of the two guide grooves, destroying the rated breaking point (2), so that the cannula carrier is rotated and moved together with the cannula (4) relative to the sealing disk (7), wherein an axial introduction groove (17), open at the bottom, for the guide peg (16) adjoins the orifice region (15'), oriented toward the sealing disk (7), of the guide grooves (15) and widens in the radial direction towards its inlet end, wherein the end (9) of the injection cannula (4) oriented toward the sealing disk (7) is closed and is provided with a lateral opening (11), through which the medication can enter the cannula, after the syringe head has been activated, and wherein the sealing disk (7') is pre-perforated, and in the unactuated state of the hypodermic syringe head the injection cannula (4) closes the hole.