Electric venetian blind

Claim 1

IN AN ELECTRICALLY OPERATED VENETIAN BLIND HAVING A HEADRAIL, AT LEAST TWO LADDER TAPES DEPENDING FROM SAID HEADRAIL NEAR OPPOSITE ENDS THEREOF, A PLURALITY OF VERTICALLY SPACED, HORIZONTALLY EXTENDING SLATS SUPPORTED BY SAID LADDER TAPES, A BOTTOMRAIL ATTACHED TO THE BOTTOM ENDS OF SAID LADDER TAPES, AND AT LEAST TWO LIFT CORDS EXTENDING DOWNWARDLY FROM SAID HEADRAIL THROUGH ALIGNED CORD HOLES IN SAID SLATS TO POINTS OF ATTACHMENT WITH SAID BOTTOMRAIL, THE IMPROVEMENT COMPRISING: A DRIVE SHAFT EXTENDING LENGTHWISE OF SAID HEADRAIL AND SUPPORTED THEREON FOR ROTATION; A PAIR OF TAPE DRUMS ROTATABLY SUPPORTED ON SAID HEADRAIL IN LINE WITH SAID LADDER TAPES, THE UPPER ENDS OF SAID LADDER TAPES PASSING ON OPPOSITE SIDES OF SAID TAPE DRUMS AND BEING ATTACHED THERETO; A PAIR OF LIFT CORD DRUMS ROTATABLY SUPPORTED ON SAID HEADRAIL IN LINE WITH SAID LIFT CORDS, THE UPPER ENDS OF SAID LIFT CORDS BEING ATTACHED TO SAID LIFT CORD DRUMS AND BEING WOUND THEREON WHEN THE DRUM IS TURNED; AN ELECTRIC MOTOR CONNECTED TO SAID DRIVE SHAFT TO DRIVE THE SAME; MEANS FOR DRIVING EACH OF SAID LIFT CORD DRUMS FROM SAID DRIVE SHAFT; AND OTHER MEANS FOR DRIVING EACH OF SAID TAPE DRUMS FROM SAID DRIVE SHAFT, INCLUDING SPEED-REDUCTION GEARS AND A CLUTCH; SAID CLUTCH BEING OPERABLE TO DRIVE SAID TAPE DRUM THROUGH A PREDETERMINED ANGULAR DISTANCE BETWEEN A FIRST EXTREMITY OF TILT IN ONE DIRECTION AND A SECOND EXTREMITY OF TILT IN THE OTHER DIRECTION, SAID CLUTCH DISENGAGING THE DRIVE TO SAID TAPE DRUM WHEN THE LATTER REACHES EITHER OF SAID EXTREMITIES AND SAID DRIVE SHAFT CONTINUES TO TURN; SAID TAPE DRUM THEREAFTER REMAINING STATIONARY WHILE SAID LIFT CORD DRUM CONTINUES TO TURN WITH SAID DRIVE SHAFT TO RAISE OR LOWER THE BLIND.