Vent-sealing, down-locked pump dispenser

摘要

The plunger may be locked down after a full depression stroke so that the overall height of the pump assembly and the container with which it is associated can be significantly reduced. A special valve component loosely encircling the plunger and slidable with friction along the interior surface of the barrel is initially positioned during factory assembly in a closed position covering vents in the sidewall of the barrel, thereby blocking the undesirable ingress of liquid into the barrel above the piston should the container be laid on its side during shipment or other handling. Upon the first unlocking upstroke of the plunger to its extended position, a shoulder on the plunger lifts the valve to an open position so the vents can function properly to introduce ambient air into the container replacing pumped-out product. The valve remains stored in its open position until such time as the plunger is once again locked down beyond the limit of its normal depression stroke, this action causing a second shoulder on the plunger to push the valve back down to its closed position.