Air circuit breaker

Claim 1

A CIRCUIT BREAKER HAVING AN ENCLOSURE OF MOLDED INSULATION, A RELATIVELY STATIONARY CONTACT ELEMENT, A MOVABLE CONTACT ELEMENT, SPRING MEANS BIASING SAID RELATIVELY STATIONARY ELEMENT TOWARDS SAID MOVABLE CONTACT ELEMENT, SAID ENCLOSURE HAVING A FORMATION PROVIDING A PASSAGE WITH A CONTACT-SURROUNDING SHOULDER AGANST WHICH SAID RELATIVELY STATIONARY CONTACT ELEMENT IS SEATED AND SEALED WHEN THE CIRCUIT BREAKER IS OPEN, AN ADDITIONAL CONTACT ELEMENT MOVABLY INTERPOSED BETWEEN THE AFOREMENTIONED CONTACT ELEMENTS SO AS TO CONSTITUE TWO CONTACT PAIRS IN SERIES ELECTRICALLY AND MECHANICALLY, SAID ENCLOSURE HAVING A FURTHER FORMATION PROVIDING A FURTHER PASSAGE BETWEEN SAID MOVABLE CONTACT ELEMENT AND SAID ADDITIONAL CONTACT ELEMENT AND PROVIDING A FURTHER CONTACT-SURROUNDING SHOULDER, RESILIENT MEANS FOR BIASING SAID ADDITIONAL CONTACT ELEMENT TOWARD SAID MOVABLE CONTACT ELEMENT, SO THAT SAID ADDITIONAL CONTACT ELEMENT IS SEATED AND SEALED AGAINST SAID FURTHER SHOULDER WHEN THE CIRCUIT BREAKER IS OPEN, AND CIRCUIT BREAKER OPERATING MECHANISM INCLUDING A POSITIVE-ACTING LINKAGE FOR DRIVING SAID MOVABLE CONTACT ELEMENT AGAINST SAID ADDITIONAL CONTACT ELEMENT AND THEREAFTER FOR DRIVING SAID MOVABLE CONTACT ELEMENT TOGETHER WITH SAID ADDITIONAL CONTACT ELEMENT AGAINST SAID RESILIENTLY MOUNTED CONTACT ELEMENT.