Light responsive non-contact shielding device

Claim 1

IN APPARATUS FOR DETECTING HOLES IN MOVING STRIP, SAID APPARATUS COMPRISING A LIGHT SOURCE POSITIONED ON ONE SIDE OF SAID STRIP AND LIGHT-SENSITIVE MEANS SUBSTANTIALLY ALIGNED WITH SAID SOURCE AND POSITIONED ON THE OTHER SIDE OF SAID STRIP, MEANS FOR PREVENTING LIGHT FROM PASSING AROUND AN EDGE OF SAID STRIP AND IMPINGING UPON SAID LIGHT-SENSITIVE MEANS, COMPRISING: (A) A LIGHT-SHIELDING DEVICE POSITIONED ADJACENT, BUT OUT OF CONTACT WITH, AND EDGE OF SAID STRIP, (B) SAID DEVICE COMPRISING A SHUTTER ADAPTED TO BE DRIVEN IN A DIRECTION TRANSVERSE TO THE PATH OF THE MOVING STRIP, (C) SAID SHUTTER COMPRISING A FIRST SHIELDING ELEMENT HAVING AN INNER EDGE EXTENDING BEYOND SAID EDGE OF THE STRIP BETWEEN SAID STRIP AND SAID LIGHT-SENSITIVE MEANS, AND A SECOND SHIELDING ELEMENT, MOUNTED ON SAID FIRST SHIELDING ELEMENT AND HAVING AN INNER EDGE IN CLOSE PROXIMITY TO SAID EDGE OF THE STRIP, (D) A SLOT IN SAID FIRST SHIELDING ELEMENT EXTENDING FROM THE INNER EDGE OF SAID FIRST SHIELDING ELEMENT TO A POINT DISPOSED SLIGHTLY INWARDLY FROM A POINT SUBSTANTIALLY VERTICALLY ALIGNED WITH THE INNER EDGE OF SAID SECOND SHIELDING ELEMENT, (E) LIGHT-SENSING MEANS, MOUNTED ON SAID FIRST SHIELDING ELEMENT IN SUBSTANTIALLY VERTICAL ALIGNMENT WITH THE INNER EDGE OF SAID SECOND SHIELDING ELEMENT, TO RECEIVE LIGHT FROM SAID SOURCE WHICH PASSES BETWEEN THE INNER EDGE OF SAID SECOND SHIELDING ELEMENT AND SAID EDGE OF SAID STRIP, (F) DRIVE MEANS IN OPERATIVE CONNECTION WITH SAID SHUTTER FOR DRIVING SAID SHUTTER, (G) REVERSIBLE MOTIVE POWER MEANS IN OPERATIVE CONNECTION WITH SAID DRIVE MEANS AND ADAPTED TO ACTUATE SAID DRIVE MEANS, AND (H) CONTROL MEANS, CONNECTING SAID LIGHT-SENSING MEANS TO SAID REVERSIBLE MOTIVE POWER MEANS, FOR ENERGIZING SAID REVERSIBLE MOTIVE POWER MEANS IN REPSONSE TO THE QUANTITY OF LIGHT STRIKING SAID LIGHT-SENSING< MEANS TO MAINTAIN THE POSITION OF SAID SHUTTER IN RELATION TO SAID EDGE OF SAID STRIP.