Loop sensing switch

Claim 1

IN AN APPARATUS FOR AUTOMATICALLY SCANNING PROCESSED FILM, A LOOP SENSING SWITCH COMPRISING: A SCANNING SLIT; A STRIP OF PROCESSED FILM; A FIRST SPROCKET ROTATING AT A CONSTANT SPEED FOR FEEDING FILM INTO A LOOP; A SECOND SPROCKET; DRIVE MEANS FOR PULLING SAID FILM FROM SAID LOOP, OVER SAID SECOND SPROCKET, AND OVER SAID SCANNING SLIT, THEREBY ROTATING SAID SECOND SPROCKET; A CAM SHAFT; A CYLINDRICAL CAM FIXEDLY MOUNTED ON SAID SHAFT AND HAVING A CAM FACE ON ONE END THEREOF; A SECOND SHAFT; A CYLINDRICAL MEMBER HAVING A CAM FOLLOWER ON ONE END THEREOF, SAID CYLINDRICAL MEMBER BEING SLIDABLY MOUNTED ON SAID SECOND SHAFT WITH ITS FOLLOWER END ADJACENT SAID CAM FACE; SPRINGS MOUNTED ON SAID SECOND SHAFT FOR BIASING SAID FOLLOWER ONTO SAID CAM FACE; SWITCH MEANS POSITIONED ADJACENT THE END OF SAID CYLINDRICAL MEMBER OPPOSITE SAID CAM FOLLOWER END FOR ENERGIZING SAID DRIVE MEANS; FIRST GEAR MEANS CONNECTED BETWEEN SAID FIRST SPROCKET AND SAID CYLINDRICAL MEMBER; AND SECOND GEAR SPROCKET AND NECTED BETWEEN SAID SECOND SPROCKET AND SAID CYLINDRICAL CAM, SO THAT THE RELATIVE MOVEMENT OF SAID FIRST AND SECOND SPROCKETS IS TRANSMITTED TO SAID CAM AND FOLLOWER CAUSING SAID CYLINDRICAL MEMBER TO ACTUATE SAID SWITCH WHEN SAID LOOP REACHES A PREDETERMINED SIZE.