The present disclosure relates to mechanical braking mechanisms used in electric motor applications. The present braking mechanisms may be configured as non-back-drivable mechanical brakes and provide immediate braking of the motors. According to one embodiment, a mechanical brake assembly for an electric motor may include a female disk having a curved groove and an abutment. The mechanical brake assembly further includes a male disk having a projection, the male disk being attached to a rotor of the electric motor. When the electric motor is energized, the projection of the male disk is allowed to rotate uninterrupted with the rotation of the rotor. However, when the electric motor is de-energized, the projection of the male disk travels within the curved groove of the female disk and abuts the abutment of the female disk, thereby stopping the rotation of the rotor of the electric motor.