An internal expanding shoe brake comprises expansion pistons (17) for forcing opposing brake shoes (2) apart. In each expansion piston (17) one adjusting pin (30) is axially movably arranged and presses against a brake shoe web (4) by means of a pressure piece (34). Said pressure piece (34) is supported on the adjusting pin by means of a ball joint so as to pivot in any direction. In order to prevent the adjusting pin (30) from being twisted inside the expansion piston (17), an anti-rotation element is provided and comprises a pressure piece projection (39) which projects over the ball joint surface (36) of the pressure piece (34), said projection interlockingly engaging in a receiving opening (40) of the adjusting pin (30) with lateral play and forming a rotational coupling connection.

An actuating device for an internal expanding brake has a restoring device for manual adjusting and restoring of an adjusting pin relative to an expanding piston. The restoring device includes an actuating pin which is mounted rotatably in a housing and is configured for transmitting a torque which is applied manually to the actuating pin, and a restoring gear mechanism which has a first gearwheel which is coupled to the actuating pin and a second gearwheel which is coupled to an adjusting nut. The first gearwheel of the restoring gear mechanism which is coupled to the actuating pin can be displaced in the axial direction of the actuating pin and can be brought into and out of torque-proof engagement with the actuating pin by means of a coupling device in a manner which is dependent on the transmitted torque.

The invention relates to an actuating device for an internal shoe brake, including an automatic adjusting device with an adjusting lever which includes a guide track in the form of a guiding slot with two opposing track surfaces which cooperate with opposing sides of a housing-fixed guide element in order to convert a displacement of the adjusting lever relative to the housing-fixed guide element into pivoting movements of the adjusting lever.

The proposal is for an improved expansion device for a drum brake having an integrated readjustment unit having a readjusting screw which can be locked therein by a spring-loaded latching unit which, for a reliable readjustment function with a reduced level of force, provides for the latching unit to allow a defined idle rotation of the readjusting screw, which is defined structurally by a first stop acting in a first direction of revolution and a second stop acting in the opposite direction of revolution.

A drum brake, in particular for a utility vehicle, has a brake drum, which is rotatably mounted about a rotational axis, and multiple brake shoes, which are mounted in a receiving area of the brake drum and each of which has a friction lining support and a friction lining arranged thereon. The brake shoes can be pressed against a brake drum casing inner surface, which is designed as a friction surface, in a radial direction relative to a rotational axis of the brake drum. The interior of the drum brake is equipped with a brake cylinder assembly which is rotationally fixed to an armature housing for actuating the brake shoes. A respective pressing wedge is arranged on the friction lining support face facing away from the friction lining. The pressing wedge lies on a wedge mechanism which can be moved in a parallel manner relative to the rotational axis of the brake drum. The wedge mechanism can be moved from a non-braking position into a braking position by moving the service brake piston of the brake cylinder assembly in a parallel manner relative to the rotational axis of the brake drum.

An expanding device for actuating one of the brake shoes of a drum brake includes a body of revolution and transmission bodies actuated by the body of revolution via ball track ramps. A spacer body is located between two partial bodies of the body of revolution, the spacer body guided by an adjustment spring keeping the partial bodies at the respectively reached distance. The spacer body is screwed onto a pin on the first partial body. A readjustment nut ensures that, when the two partial bodies are pushed apart, the spacer body rotates on the pin and moves away from a supporting surface on a partition of the second partial body. Upon renewed actuation of the brakes, the readjustment nut is guided such that the spacer body bears against the second partial body, but takes up a different position on the pin, the position corresponding to the air clearance readjustment.

An electromechanical spreader device for a drum brake of a vehicle, comprising an electric motor with an output, a cam disc connected to the output so as to transmit torque and is arranged between two actuating elements for simultaneously actuating the two actuating elements during a braking action. The cam disc is connected to an actuating disc of a stepping gear so as to transmit torque. The stepping gear is connected to a second of the two actuating elements so as to transmit force, such that the second actuating element is adjustable via rotation of the cam disc in an engagement angle of rotation range, in which the actuating disc is in torque-transmitting engagement with a remaining part of the stepping gear, and is adjustable away from the brake shoe in the opposite direction in the engagement angle of rotation range via rotation of the cam disc.

An apparatus for a drum brake assembly having first and second brake shoes includes a motor and a gear train for receiving torque from the motor and having a pinion gear. First and second ball ramp assemblies receive torque from the pinion gear and have ends aligned with the respective first and second brake shoes. The motor is actuatable for lengthening each ball ramp assembly to move the brake shoes and apply braking force to the brake drum.