Dome-bottomed container

Claim 1

In a container for paste, and the like, comprising a hollow base member and a main chamber member, said main chamber member having a substantially flexible resilient annular wall member comprising a continuous helical bellows in the form of a helical thread having a central axis and biased to an extended position by the inherent resiliency of said wall member, said wall member including a short cylindrical wall portion which terminates downwardly at an annular bottom edge portion which is situated in a plane substantially perpendicular to said axis, said thread terminating downwardly at said substantially cylindrical wall portion, said main chamber member having a closed bottom and having a discharge opening at the top, said wall member thread being adapted to be screwed directly into and collapsed within said hollow base member; said hollow base member having a threaded opening at the top thereof for threadingly engaging said thread, and chamber member stop means spaced from said threaded opening a sufficient distance to receive said wall member in collapsed condition within said base member, the improvement in which: the closed bottom of the chamber consists of a smoothly curving flexible bottom member which begins radially outwardly at said annular bottom edge portion of said wall member, angles abruptly radially inwardly toward the central axis of the container, then curves smoothly away from said plane of said edge portion, and inwardly with respect to the central axis of the container, and thereupon terminates in a smoothly rounded, closed central portion, said flexible bottom member being of sufficient flexibility to permit involution to a position within said wall member.