Safety brake system for robot arm joints

Abstract

The invention relates to a safety brake system comprising a round rotatable shaft locked with a constant-on braking device activated by a spring and a switch-off device for the braking device that counteracts the spring, so that the shaft is unlocked and can rotate when the switch-off device is active. According to the invention the constant-on brake device comprises a brake shoe pushed against the shaft by the spring and the switch-off device is a piezo actuator that counteracts the spring. The brake system is normally constant on since the spring pushes the brake shoe against the shaft. When the shaft needs to rotate the piezo actuator counteracts the spring, thus releasing the brake shoe from the shaft. In case of an emergency or when the shaft needs to be locked, the power to the piezo activator is shut off and the spring pushes the brake shoe against the shaft to stop any rotation.

Dependencies are inferred from the claim text.