Syringe for medical use - in which unauthorised further use is automatically prevented e.g. by blade which penetrates syringe wall during first use etc.

摘要

A syringe has a cylinder (2) in side which is a plunger (3) whose shaft (5) projects from the end (4) of the cylinder. An opening (9) at the other end of the cylinder is provided for the fitting of an injection needle etc.. At least one cutting or blocking element (11) is located at the rear (12) of the plunger shaft, and is brought into action during or after use of the syringe in order to prevent it being used again. The cutting element (11) is moved radially outwards by the plunger shaft during operation of the syringe and penetrates the wall (13) of the cylinder. The cutting element is carried in a sliding spool (14) so that it is kept free of the cylinder wall during a suction movement of the plunger but is pressed into the wall during a delivery movement by a contact surface (16) on the plunger shaft. This contact surface is conical in shape. The forward surface (17) of the sliding spool is flat, while its rear surface (18) is at least partly tapered to correspond with the contact surface of the plunger shaft. USE/ADVANTAGE - Used in the design of syringes, esp. for medical use. The proposed design provides a disposable syringe which automatically damages itself during its first use, so that unauthorised further use is made impossible. (20pp Dwg.No.1/39)