Injection syringe
AssigneeMedi Plus Tec Medizinisch-Technische Handelgesellschaft mbH
InventorMatthias Wirtz
Life of this patent
Estimating the term…
Abstract
A tubular barrel having an inner surface with threads at a front end ther receives a chuck having corresponding threads for engaging the chuck to the barrel, the chuck having additional threads in an opposite sense for engaging a needle hub thereto. A piston received slidably in the barrel engages the rear of the chuck and is fixed against rotation relative to the hub, whereby a piston stem protruding from the rear of the barrel can be used to engage the chuck to the front end of said barrel. Cams provided on the inside surface cooperate with flexible cam followers on the chuck to make disengagement of the chuck from the barrel more difficult than engagement. A circumferential rib provided on the inside surface at the rear of the barrel impedes withdrawal of the piston, the stem being frangible to prevent the reuse.
Claims11
Injection syringe comprising
- a tubular barrel having a first end, a second end, a cylindrical inner surface extending between said ends, and first thread means on said inner surface adjacent said first end,
- a chuck received slidably in said tubular barrel and having second thread means rotationally engagable with said first thread means,
- locking means between said inner surface of said tubular barrel and said chuck, said locking means being effective to make disengagement of said second thread means from said first thread means more difficult than engagement of said second thread means on said chuck to said first thread means,
- piston means comprising a piston received slidably in said tubular barrel and a piston stem protruding from said second end of said tubular barrel, and
- antirotation means for engaging said piston to said chuck so that said piston cannot be rotated relative to said chuck.
Dependencies are inferred from the claim text.