PLUNGER FOR PNEUMATIC DISPENSER

摘要

The present invention is a plunger (10) for a pneumatic dispenser having a first portion (80) having a solid structure, and a second portion (82) having a hollow structure, wherein the external peripheral surface of the first portion (80) has a first ring groove (92) and a first land (94), the second portion (82) has an internal peripheral surface (86) that is a tapered surface, and has an inner wall part (84) in which the thickness is reduced in commensurate fashion to the distance in the axial direction from the first portion (80), the external peripheral surface of the second portion (82) furthermore has a second ring groove (102) and a second land (104), and the outside diameter of the first land (94) is less than the outside diameter of the second land (104) in a free state in which external force does not act on the plunger (10). In accordance with this configuration, air is allowed to escape and a viscous material can be prevented from leaking when the viscous material is loaded into the dispenser; and compressed air can be prevented from leaking to the viscous material side when the viscous material is discharged from the dispenser.