Sprag solenoid brake

Claim 1

An electrically operated brake comprising: a. a housing having a cylindrical chamber provided therein defined by an inner surface, b. a rotary member carried within said cylindrical chamber for rotation about a longitudinal axis of said cylindrical chamber; c. circumferentially spaced sockets disposed in an outer surface of said rotary member; d. at least one pair of sprags each having a rounded end portion and an opposite wedging end portion; e. said end portions being respectively disposed in said sockets of said surface of said rotary member and in engagement with said inner surface of said cylindrical chamber; f. spring means urging the sprags of each pair in opposite directions in the sockets thereof for wedging engagement with said inner surface of said cylindrical chamber; g. a control member coaxially disposed on said rotary member; h. means coupling said control member to said rotary member for rotation therewith while permitting said control member to be shifted longitudinally thereto, i. electrically operated means for urging said control member to a first longitudinal position on said rotary member when energized; j. means for urging said control member to a second longitudinal position on said rotary member when said electrically operated means is de-energized; k. inclined means carried adjacent one end of said control member for permitting said spring means to force said sprags into wedging engagement with said inner surface of said housing when said control member in in one of said longitudinal positions and for spreading said sprags out of wedging engagement with said inner surface when said control member is in the other longitudinal position; whereby said rotary member can be maintained in a fixed or freely rotating position relatiVe to said housing.