Racking mechanism including a differential pulley system

Claim 1

IN SWITCHGEAR APPARATUS: A RELATIVELY STATIONARY ENCLOSURE UNIT INCLUDING A PAIR OF SPACED SIDEWALLS; A MOVABLE UNIT DISPOSED BETWEEN THE SIDEWALLS OF SAID ENCLOSURE UNIT AND ADAPTED TO SUPPORT AN ELECTRIC CIRCUIT INTERRUPTER; AND A RACKING MECHANISM FOR MOVING SAID MOVABLE UNIT RELATIVE TO THE ENCLOSURE UNIT BETWEEN DIFFERENT PREDETERMINED POSITIONS, THE RCKING MECHANISM COMPRISING: (A) A PAIR OF INTERENGAGEABLE CAMMING ELEMENTS MOUNTED ON SAID ENCLOSURE AND MOVABLE UNITS, RESPECTIVELY, WITH ONE OF THE ELEMENTS BEING SO MOVABLE RELATIVE TO THE OTHER THAT THE COACTION THEREBETWEEN WILL DRIVE SAID MOVABLE UNIT BETWEEN ITS PREDETERMINED POSITIONS, (B) A RATCHET WHEEL FOR MOVING SAID ONE ELEMENT UPON ANGULAR ADVANCEMENT OF THE WHEEL, (C) A RATCHET OPERATING PAWL DISPOSED ADJACENT TO SAID WHEEL FOR ADVANCEMENT OF THE WHEEL, THE PAWL IN A PREDETERMINED DIRECTION, (D) MEANS FOR BIASING SAID PAWL IN A DIRECTION OPPOSITE TO SAID PREDETERMINED DIRECTION, (E) A DIFFERENTIAL PULLEY SYSTEM FOR MOVING SAID PAWL IN SAID PREDETERMINED DIRECTION, SAID DIFFERENTIAL SYSTEM INCLUDING (I) AN OUTPUT PULLEY CONNECTED TO SAID PAWL (II) A DOUBLE PULLEY DISPOSED FOR LIMITED ROTATION ABOUT AN AXIS WHICH IS FIXED RELATIVE TO THE AXIS OF SAID RATCHET WHEEL, THE DOUBLE PULLEY HAVING GREATER AND LESSER RIMS OF DIFFERENT DIAMETERS, AND (III) A FLEXIBLE CABLE ATTACHED AT ONE END TO SAID GREATER RIM, LOOPED TAUTLY OVER THE OUTPUT PULLEY AND WRAPPED AROUND SAID LESSER RIM TO WHICH ITS OTHER END IS ATTACHED, WHEREBY THE OUTPUT PULLEY MOVES SAID PAWL IN SAID PREDETERMINED DIRECTION IN RESPONSE TO CONSTRICTION OF THE CABLE LOOP UPON ROTATION OF THE DOUBLE PULLEY IN A PREDETERMINED FORWARD DIRECTION TO UNWIND THE CABLE WRAPPED AROUND SAID LESSER RIM, (F) A DRIVING PULLEY DISPOSED ADJACENT TO SAID DOUBLE PULLEY FOR ROTATION ABOUT THE SAME AXIS, SAID DRIVING PULLEY BEING OPERATIVELY COUPLED TO THE DOUBLE PULLEY WHICH IS THEREBY ROTATED IN SAID FORWARD DIRECTION IN RESPONSE TO ROTATION OF THE DRIVING PULLEY IN A CORRESPONDING DIRECTION, (G) COIL SPRING MEANS FOR NORMALLY BIASING BOTH SAID DRIVING PULLEY AND SAID DOUBLE PULLEY IN A REVERSE DIRECTION, (H) A MANUALLY OPERATIVE HANDLE, AND (I) A FLEXIBLE CONNECTING MEMBER ANCHORED TO SAID HANDLE AND WRAPPED AROUND SAID DRIVING PULLEY FOR ROTATING THE DRIVING PULLEY IN ITS FORWARD DIRECTION, THEREBY MOVING SAID PAWL AND HENCE INCREMENTALLY ADVANCING SAID RATCHET WHEEL, UPON OPERATION OF THE HANDLE.