FAIL-SAFE SYSTEM, ACTUATOR, ACCUMULATOR USED IN THIS SYSTEM, MACHINE TOOL USING THIS SYSTEM, FAIL-SAFE TABLE, AND FAIL-SAFE HOLDER

摘要

PURPOSE:To prevent a mechanical member from being damaged, and to prevent failure of an entire production and process system or the like by stopping the motion of an actuating element when it is detected that a moving element which is moved by a force greater than a set value, applied by the actuating element is moved by a predetermined displacement. CONSTITUTION:Force applied to pistons 5, 6 as moving elements from an external actuating element acts upon a compression spring 9 between an end wall 3 and a flange 7 and a compression spring 10 between a partition wall 2 and a flange 8 in series, and only one of the pistons 5, 6 is moved when the force exceeds a predetermined value. When this force becomes greater than a set value with respect to both normal and reverse directions, the pistons 5, 6 serve as an actuator 47 which performs retraction. Further, when the end-to-end distance between both pistons 5, 6 varies exceeding a predetermined value, microswitches or the like detects this matter so as to stop the motion of the actuating member or the motion of the machine. Thus, it is possible to surely prevent damage of mechanical parts, failures of an entire production and process system and the like.