Abstract: An overload protector is provided which is secured to a robot arm and a tool to protect the tool form being overloaded or forced into an abnormal position. A rocker assembly is located within the cavity in the protector and the cavity is pressurized in order to force a wall of the rocker assembly into a sealing relationship with a wall of the cavity. The rocker assembly has a peripheral wall in which a number of semi-conical detents are formed in the wall of the cavity. The detents are accommodated in the recesses when the rocker assembly is in a sealing relationship with the cavity wall. When the tool is overloaded or forced into an abnormal position the rocker assembly rocks in the cavity with resulting leakage of fluid from the cavity and a drop of pressure. A pressure switch detects that drop and signals the robot to stop.