| 摘要 |
The plunger may be releasably locked in a fully extended condition against depression by an annular locking disc which receives the plunger and has a series of radially inwardly projecting, circumferentially spaced, plunger-engaging teeth snapped into a notch on the plunger. The teeth are slightly outwardly inclined in the direction of plunger extension, and stationary structure on the pump adjacent the plunger cooperates with the teeth to prevent them from being reversely flexed when depression of the plunger is attempted, thereby securely locking the same in its upwardly extended position. By gripping a tab on the disc and flexing it upwardly so as to reversely flex at least certain of the teeth, attempted depression of the plunger while the teeth are in that condition will release the plunger so that full depression may continue. The disc becomes stored on the plunger on the first lock-releasing stroke and remains snugly against the underside of the dispensing head unless the disc is once again intentionally slid downwardly from its unlocked position along the plunger into locking engagement with the notch.
|
