Compact ratchet type hoisting gear - good mechanical advantage from eccentric pinion and double roller system

摘要

A compact ratchet type hoisting gear includes a U section crown (1) secured inside the winding drum (2) and around which travels a set of double rollers, their common spindles (4) projecting to roll around the arms of the U section, one of the rollers (6) of each pair travelling around a track (6) on a collar attached to the winding spindle (3) carrying the crank arm (11). The other roller (5) of each pair progressively engages the teeth of an eccentric pinion (9) forming the end of a bush (10) rotating on the spindle (3), supported also by a set of four rollers (14) projecting from it to travel also around the collar on the winding spindle.