Pump dispensers

A pump dispenser has a pump body and a reciprocable plunger with a lock-down mechanism, including internal or external lock formations of the plunger and body, such as thread formations, by which the plunger can be locked down for shipping and released subsequently by a rotational release movement. To supplement security for demanding shipping conditions the dispenser also has a supplementary catch mechanism in which respective catch formations of the plunger and body engage selectively in the locked-down position to inhibit the rotational release movement. The catch formations may have circumferentially-directed surfaces which engage between the underside of a plunger head having a shroud and a nozzle and the top of the body beneath the plunger head. They can be released by resilient deformation of one or more of the catch formations.