PURPOSE: To miniaturize a bushing while preventing its breakage by the impact at the time of closing a vacuum valve, and miniaturize the whole device.
CONSTITUTION: When a pressing element is energized on the side of a movable lead 52b, and the movable lead 52b is driven at once toward a fixed lead 52a, two electrodes are collided to each other, and the fixed lead 52a is moved in the direction opposite to the movable lead 52b. After the fixed lead 52a pushes an inner cylinder 56a in a dumper spring mechanism 56 toward a small diameter part 50b, then, it is pushed back by the restoring force of the spring 56c and returned to about the initial state. Although an outer cylinder 56b is pressed through the spring 56c, the impact received by the fixed lead 52a is sufficiently dumped, and the impact received by a lead bushing 50 with which the outer cylinder 56b makes contact is small.
NAGASAKA HIROMI
HATTORI TAKASHI
