Patent ID: 9561329
Date: 2017-02-07
CPC Classifications: A61M

Claim:
1. A piston for a micro-volume syringe having a syringe barrel with a space defined therein, said piston comprising a leading member and a trailing member and being slidable on and along a wall of the space, wherein the leading member is arranged on a first side of the piston where the piston comes into contact with a solution filled in the space, the leading member includes a side wall and a top wall that forms an entire top surface of the leading member facing the solution filled in the space, and the top wall has no openings therein, the trailing member is arranged on a second side of the piston where a plunger rod is to be connected, the second side being opposite to a solution side of the leading member, the leading member comprises a first recess formed on a bottom surface of the leading member located on the second side, the trailing member comprises the leading member has an outermost diameter that is greater than the outermost diameter of the main body, the protrusion is welded with the first recess in a state in which the protrusion is fitted in the first recess, a distance from the innermost surface of the second recess to the bottom end surface being smaller than a distance from the forward end surface to the bottom end surface, and the trailing member has a higher hardness than the leading member.