Pump and over-center snap link

摘要

A pump is disclosed which includes a snap-over mechanism useful for small floats with little buoyancy. The snap-over mechanism has a geometry in which the distance between the float or compression arm pivot point and the pivot for the portion of the spring connected to a first arm or toggle link is greater than the distance from the float or compression arm pivot point and the pivot for the portion of the spring connected to the float or compression arm. This geometry allows the magnification of buoyancy by the main arm which is transmitted to the first toggle link to be large and the magnification of buoyancy by the first toggle link which is transmitted to the change-over valve to be large.