A variable resistance brake clutch facilitates a rotational coupling of electronic device components, and can include a rotatable shaft, a brake disposed proximate the rotatable shaft, and an actuator coupled to and configured to actuate the brake. The brake applies a braking force against a rotational motion of the shaft, and release of the brake results in low to no frictional resistance against the rotational motion. The braking force can be provided by default, and a capacitive touch sensor or other input component can allow a user to actuate the actuator manually to release the brake when desired. The release can be maintained as long as the sensor detects the touch event or other user input. A processor and solenoid can facilitate actuation by on a touch event, which sensor can be located at a back corner of a laptop upper component.

A brake assembly including a rotor defining an aperture. An axis of rotation of the brake assembly extends through a center of the aperture. A spindle is within the aperture. The spindle is in cooperation with the rotor to restrict independent rotation of the rotor and the spindle about the axis of rotation, restrict axial movement of the rotor relative to the spindle along the axis of rotation, and accommodate radial expansion of the rotor in a plane perpendicular to the axis of rotation.

In some examples a piston-bushing assembly includes a bushing with an opening and a piston slidably disposed within the bushing. The piston includes a bottom end disposed within the bushing and an exterior end extending a distance outward from the opening of the bushing. The exterior end of the piston is configured to engage with a disc stack of a brake assembly. The piston-bushing assembly also includes an adjuster tube including a first end of the adjuster tube, wherein, when the piston-bushing assembly is in an unactuated state, a length between the first end of the adjuster tube and the bottom end of the piston defines a step-back gap.