Safety switch device for power operated tools

Claim 1

IN COMBINATION WITH AN ELECTRICALLY POWERED TOOL HAVING AN ADJUSTABLE DRIVEN ELEMENT AND A KEY FABRICATED OF FERROUS METAL FOR ADJUSTING SAID DRIVEN ELEMENT, THE IMPROVEMENT COMPRISING SWITCH MEANS FOR CONTROLLING ELECTRIC POWER INPUT TO SAID TOOL INCLUDING A BOX HAVING A FACE PLATE FABRICATED OF A NON-MAGNETIC MATERIAL, SAID FACE PLATE PROVIDING AN EXPOSED SURFACE EXTERNALLY OF SAID BOX, A SUPPORT MEMBER FABRICATED OF A FERROUS METAL DISPOSED WITHIN SAID BOX, FIRST AND SECOND MAGNETS SUPPORTED BY SAID SUPPORT MEMBER WITH THE NORTH POLE OF SAID FIRST MAGNET AND THE SOUTH POLE OF SAID SECOND MAGNET ADJACENT SAID SUPPORT MEMBER, SPRING MEANS FOR SUPPORTING SAID SUPPORT MEMBER AND MAGNETS FOR MOVEMENT FROM A POSITION NEARER SAID FACE PLATE TO A POSITION MORE REMOTE FROM SAID FACE PLATE AND YIELDABLY FORCING SAID SUPPORT MEMBER AND MAGNETS TO THE POSITION MORE REMOTE FROM SAID FACE PLATE, A PAIR OF ELECTRICAL CONTACTS RESPONSIVE TO MOVEMENT OF SAID SUPPOORT MEMBER WHEREBY SAID CONTACTS ARE CLOSED WHEN SAID SUPPORT MEMBER IS IN SAID NEARER POSITION, BUT NOT OTHERWISE, WHEREBY WHEN SAID KEY IS PLACED AGAINST SAID EXPOSED SURFACE OF SAID FACE PLATE SAID MAGNETS AND SUPPORT MEMBER ADVANCE TOWARD SAID FACE PLATE, SAID CONTACTS CLOSE, AND SAID MAGNETS, SUPPORT MEMBER, AND KEY TOGETHER FORM A SINGLE CLOSED SERIES MAGNETIC CIRCUIT TO HOLD SAID KEY SECURELY AGAINST SAID FACE PLATE.