Flyweight actuated clutch

Abstract

The clutch is adapted forum& in starting-and restarting aircraft turbine engines with a pneumatically operated starter turbine. The clutch assembly has one clutch member which is driven by the starter turbine and another clutch member which is connected to and drives the turbine engine. The starter turbine clutch member is translationally moveable toward and away from the turbine engine clutch member. Centrifugally operated flyweights are used to induce the translational movement of the clutch member. Proengagement flyweights are operable when the starter turbine is rotating to urge the starter turbine clutch member toward the turbine engine clutch member; and disengagement flyweights are operable when the turbine engine is rotating to urge the starter turbine clutch member away from the turbine engine clutch member. The mass of the proengagement flyweights is preferably twice that of the disengagement flyweights to provide increased proengagement forces so that the starter turbine clutch member will be forced into extended ratcheting engagement with the turbine engine clutch member during turbine engine restart. Angled splines are used to positively twist the starter turbine clutch member into full engagement with the turbine engine clutch member once the rotational speed of both starter turbine and turbine engine are essentially equal during restart. A rotating stop surface is provided to resist axial forces imposed on the engaged clutch members during driving engagement to allow the higher proengagement forces without incurring bearing damage.