| 摘要 |
PROBLEM TO BE SOLVED: To provide a syringe having a gasket superior in adhesion to the inner wall of an outer cylinder, reduced in total length and easily manufacture able. SOLUTION: This syringe includes the gasket 6 sliding in close contact with the inner wall 4a of the outer cylinder 4. The gasket 6 is a substantially disc- like body in which the whole side is a curved surface having a projected circular arc in the direction of the inner wall 4a along a plunger 5, and closely adheres to the inner wall 4a at a part of the curved surface. The gasket is jointed to a pedestal 10 through a hole part with a bendable space on the forward end side of the plunger 5. The surface on the plunger 5 side is provided with an annular groove part having a large diameter than the pedestal 10, and a bent part is provided on the outer peripheral side of the annular groove part. The bent part is bent in the axial direction of the plunger 5 taking the base of the annular groove part as a fulcrum when the gasket 6 slides in the axial direction of the outer cylinder 4. In the bent part, the distance between the base of the annular groove part and a peak P of the curved surface is smaller than the radius of curvature of the curved surface. The gasket 6 is formed of a synthetic resin having Shore (A) hardness of 20 to 70. |
