Activated changeable advertising sign

Claim 1

IN AN ADVERTISING SIGN; COMPRISING A CASING HAVING A DISPLAY OPENING; SAID CASING HAVING UPPER AND LOWER APERTURED METAL MOUNTING BARS; A PLURALITY OF UPWARDLY EXTENDING SPACED APART TRIANGULARLY FACED SIGN-BEARING UNITS, EACH OF SAID SIGN-BEARING UNITS HAVING MOUNTED THEREON A JOURNALLED UPPER SHAFT AND A DEPENDING PARALLEL LOWER SHAFT; SAID SHAFTS ROTATABLY MOUNTING SAID SIGN UNITS RELATIVE TO SAID BARS; A PLURALITY OF HUB MEMBERS OPERATIVELY MOUNTED ON SAID LOWER SHAFTS RESPECTIVELY, EACH OF SAID HUB MEMBERS HAVING A PLURALITY OF RADIAL STUDS MOUNTED IN DIFFERENT VERTICAL PLANES; A TRANSVERSE POWER DRIVEN SHAFT JOURNALLED IN THE LOWER PORTION OF SAID CASING; A PLURALITY OF DRIVING SPROCKETS MOUNTED IN TRANSVERSELY SPACED APART RELATION ON SAID DRIVEN SHAFT, EACH OF SAID SPROCKETS HAVING A PLURALITY OF RADIAL ARMS OF VARYING LENGTHS THEREON; SAID ARMS WHEN ROTATED, BEING ADAPTED TO ENGAGE AND PUSH SAID STUDS OF SAID HUBS RESPECTIVELY TO CAUSE INTERMITTENT PARTIAL ROTATION OF SAID SIGN-BEARING UNITS; TO THEREBY SUCCESSIVELY PRESENT TO VIEW THE CORRESPONDINGLY MATCHING FACES OF SAID SIGN UNITS; EACH ONE OF SAID ARMS BEING ADAPTED TO ENGAGE ONLY ONE OF SAID STUDS WHEREBY OBSTRUCTED STOPPAGE OF ROTATION OF ANY ONE OR MORE OF SAID SIGN UNITS WILL CAUSE ONE OF SAID ARMS TO UPWARDLY ELEVATE SAID OBSTRUCTED SIGN UNIT INTO UPPER NON-OPERATING POSITION WHEREIN STUDS CONNECTED TO SAID OBSTRUCTED UNIT WILL NOT BE CONTACTED BY THE ARMS OF THE ADJACENT SPROCKET.