Ventilating skylight with two simultaneously operated closures

Claim 1

A SKYLIGHT CONSTRUCTION COMPRISING A DUCT HAVING A CLOSED UPPER END AND A CLOSED LOWER END, AN UPPER APERTURE IN SAID UPPER END AND A LOWER APERTURE IN SAID LOWER END, AN UPPER CLOSURE MEMBER MOVABLE INTO AND OUT OF CLOSED POSITION AGAINST SAID UPPER APERTURE, A LOWER CLOSSURE MEMBER MOVABLE IN A STRAIGHT VERTICAL DIRECTION INTO AND OUT OF CLOSED POSITION AGAINST SAID LOWER APERTURE, MEANS TO MOVE AND UPPER AND LOWER CLOSURE MEMBERS SIMULTANEOUSLY INTO CORRESPONDING OPEN AND CLOSED POSITIONS, SAID MEANS COMPRISING AN ELECTRIC MOTOR FIXEDLY MOUNTED WITHIN SAID DUCT, A VERTICAL ROD HAVING A LOWER END PIVOTALLY CONNECTED TO SAID LOWER CLOSURE MEMBER AND HAVING ITS UPPER END PIVOTALLY CONNECTED TO A FIRST LINK, SAID FIRST LINK BEING OPERATIVELY CONNECTED TO THE DRIVE SHAFT OF SAID MOTOR, A SECOND LINK OPERATIVELY CONNECTED TO THE DRIVE SHAFT OF SAID MOTOR FOR SYNCHRONOUS OPERATION WITH SAID FIRST LINK, AN OPERATING ARM HAVING ONE END PIVOTALLY CONNECTED TO SAID SECON LINK AND AN OPPOSITE END PIVOTALLY CONNECTED TO SAID MOTOR TO MEMBER, AND MEANS OPERATIVELY CONNECTING SAID MOTOR TO A SOURCE OF ELECTRICAL ENERGY, AND A SCREEN PROVIDED AROUND THE LOWER APERTURE, SAID SCREEN HAVING A VERTICAL PORTION EXTENDING UPWARDLY FROM THE LOWER APERTURE AND A HORIZONTAL PORTION EXTENDING RADIALLY INWARD FROM THE UPPER EDGE OF THE VERTICAL PORTION, SAID HORIZONTAL PORTION FORMING A STOP MEANS FOR THE OPENING MOVEMENT OF SAID LOWER CLOSURE MEMBER.