Sound and slide synchronizing arrangement

Claim 1

IN A PICTURE SLIDE CHANGER, AN ARRANGEMENT FOR ADVANCING A PICTURE SLIDE ADVANCE SHAFT STEP BY STEP COMPRISING A STAR WHEEL AND A SPROCKET WHEEL KEYED TO SAID SLIDE ADVANCE SHAFT, A DRIVE WHEEL HAVING A DRIVE TOOTH FOR INTERMITTENTLY ENGAGING SAID SPROCKET WHEEL TO DRIVE SAID SPROCKET WHEEL, MEANS FOR LOCKING SAID STAR WHEEL AUTOMATICALLY AGAINST ROTATION WHEN SAID DRIVE TOOTH MOVES OUT OF ENGAGEMENT WITH SAID SPROCKET WHEEL, SAID DRIVE WHEEL HAVING A CAMMING SURFACE, SAID LOCKING MEANS COMPRISING A FIRST ARM RESILIENTLY URGED TO FOLLOW SAID CAMMING SURFACE AND A SECOND ARM RESILIENTLY URGED TO ENGAGE SAID STAR WHEEL FOR LOCKING SAID STAR WHEEL, SAID FIRST ARM RESPONSIVE TO A FIRST CAMMING ACTION OF SAID CAMMING SURFACE TO MOVE SAID SECOND ARM OUT OF LOCKING ENGAGEMENT WITH SAID STAR WHEEL AUTOMATICALLY WHEN SAID DRIVE TOOTH MOVES INTO DRIVING ENGAGEMENT WITH SAID SPROCKET WHEEL AND FOR MAINTAINING SAID SECOND ARM OUT OF LOCKING ENGAGEMENT WITH SAID STAR WHEEL DURING THE PERIOD WHEN SAID DRIVE TOOTH IS DRIVING SAID SPROCKET WHEEL, SAID FIRST ARM RESPONSIVE TO A SECOND CAMMING ACTION OF SAID CAMMING SURFACE FOR RETURING SAID SECOND ARM INTO LOCKING ENGAGMENT WITH SAID STAR WHEEL AUTOMATICALLY WHEN SAID TOOTH MOVES OUT OF DRIVING ENGAGEMENT WITH SAID SPROCKET WHEEL.