Patent attributes
A parking brake for a wheel rotor having a brake pad associated therewith includes a housing defining first and second passages. First and second pistons are provided in the respective first and second passages. Spindles are threadably connected with each piston. A clutch unit is connected to the spindles. The clutch unit has a first condition allowing relative rotation between the spindles and the pistons such that the pistons are axially movable within the passages and into engagement with the brake pad in response to hydraulic pressure applied to the pistons. The clutch unit has a second condition preventing relative rotation between the spindles and the pistons such that pistons remains engaged with the brake pad when hydraulic fluid pressure is removed from the pistons.