Patent ID: 6082504
Filing Date: 2000-07-04
Classification: F16D

Abstract:
A friction brake comprising:a housing having a cavity formed therein;a shaft rotatable relative to said housing;a brake surface extending from said housing;a primary ball ramp mechanism disposed within said cavity comprising:an activation ring disposed adjacent to said brake surface where axial movement of said activation ring results in a frictional loading and unloading of said activation ring against said brake surface; a control ring disposed opposing said activation ring, said control ring and said activation ring having opposed faces provided with circumferentially extending grooves, said grooves comprised of at least three opposed pairs of grooves having portions of varying depth with a maximum depth at a center and a minimum depth at either of two ends; rolling members disposed one in each opposed pair of said grooves; said grooves in said control ring and said activation ring being arranged so that relative angular movement of said control ring relative to said activation ring in either a clockwise or counterclockwise direction from a starting position thereof, causes said rolling members to roll along each opposed pair of said grooves thereby causing axial movement of said activation ring away from said control ring to axially load said activation ring against said brake surface thereby providing a braking torque on said shaft relative to said housing;a clamp ring attached to said control ring;a secondary ball ramp mechanism activated by the movement of a control lever creating a clamping force on said clamp ring to activate said primary ball ramp mechanism, said secondary ball ramp mechanism including at least one pair of opposed grooves formed in said secondary ball ramp mechanism, said grooves having a variable depth along their length and a rolling member disposed between said opposed grooves and wherein said secondary ball ramp mechanism further comprises a control plate axially slidingly supported by said housing and acted upon by said rolling member wherein the first of said pair of opposed grooves is formed in said control lever and the second of said pair of opposed grooves is formed in said control plate.