Patent ID: 6796217
Filing Date: 2004-09-28
Classification: A61C,A61M

Abstract:
A plunger for being inserted in a tubular barrel in an axially movable manner, the barrel having a distal end forming a discharge port and a proximal end forming an inlet opening, the plunger comprising:a plunger body having a distal end positioned within said barrel and a proximal end positioned outside of the barrel, and a seal member disposed on said distal end of the plunger body, wherein said seal member has a base portion extending from the plunger body towards the distal end of the barrel, and a flange portion radially outwardly extending from said base portion and having a peripheral edge contacting an inner circumference of said barrel so as to define an accommodation space within the barrel, said peripheral edge being formed into a spherical shape; and said flange portion is elastically deformed to be brought into an elastically deformed state by means of reaction force from a material accommodated within said accommodation space when the seal member is slid towards the distal end of the barrel by means of pressing force applied onto the plunger body so as to force the material out of the accommodation space, and presses the plunger body back towards the proximal end of the barrel by means of self-restoring force of the flange portion when the pressing force is released from the plunger body.