Dispensers for fluent masses

Claim 1

In a dispenser for a fluent mass: a pliant, elastic container for the mass and having a discharge outlet, said container being adapted to be deformed by squeezing at all locations throughout its length; pliant, elastic laterally deformable piston follower means in said container movable toward the outlet and against the mass in the container, said follower means having seal means thereon slidably and sealingly engaging the inner wall of said container to prevent rearward leakage of fluid past said seal means and forward leakage of air past said seal means; said follower means including one-way latch means engageable with the container wall for preventing substantially all movement of said follower means in said container in a rearward direction away from said outlet while permitting movement of said follower means in the container in the forward direction; squeezing of any portion of said container forwardly of said follower means reducing the volume of said container forwardly of the follower means to dispense a portion of the mass through the discharge outlet, said container portion then returning to its initial shape to create a partial vacuum in said container forwardly of said follower means, whereby said one-way latch means releases and said follower means is moved by air at atmospheric pressure forwardly in said container toward said outlet, squeezing of said container in the region of said follower means and rearwardly of said follower means deflecting said follower means and latch means and causing said latch means to move said follower means in a forward direction within said container; and means for closing said outlet against flow of fluid therethrough into said container.