Patent ID: 7306124
Filing Date: 2007-12-11
Classification: B05B,B65D,G01F

Abstract:
1. A piston configured to be engaged inside a cylindrical container, constituted by an elastic member comprising: a sliding member having an upper fluidtight portion and a lower fluidtight portion, both of which fluidtightly and slidably contact an inner wall of the cylindrical container; and a support member connected to the sliding member and having concentric flexions for urging the sliding member against the inner wall of the cylindrical container, wherein the sliding member extends upward and downward from a position where the support member is connected to the sliding member, wherein a portion of the sliding member extending upward has the upper fluidtight portion which is constituted by at least one annular convex bump portion having a thickness which is the greatest at a point where the annular convex bump portion is in contact with the inner wall of the cylinder, wherein a portion of the sliding member extending downward has the lower fluidtight portion which is constituted by at least one annular convex bump portion having a thickness which is the greatest at a point where the annular convex bump portion is in contact with the inner wall of the cylinder, wherein the position where the support member is connected to the sliding member is located nearly halfway between the upper end and the lower end of the sliding member.