Control for electric hoists

Claim 1

A CONTROL CIRCUIT FOR ELECTRIC HOIST MECHANISMS COMPRISING AN ELECTRIC POWER SOURCE, AN ELECTRIC HOIST MOTOR, RELAY MEANS FOR SELECTIVELY CONNECTING SAID POWER SOURCE TO SAID MOTOR FOR OPERATION OF THE MOTOR SELECTIVELY IN BOTH DIRECTIONS OF ITS ROTATION TO IMPART EITHER A LIFTING OR A LOWERING MOTION TO AN ASSOCIATED LOAD, AN OVERLOAD RELAY, A PAIR OF MANUALLY CONTROLLED SWITCHES, ONE FOR OPERATING THE HOIST MOTOR IN THE LIFTING DIRECTION AND THE OTHER FOR OPERATING THE HOIST MOTOR IN THE LOWERING DIRECTION, EACH OF SAID MANUALLY CONTROLLED SWITCHES BEING CONNECTED TO SAID RELAY MEANS AND SAID OVERLOAD RELAY, SAID OVERLOAD RELAY INCLUDING A NORMALLY OPEN SWITCH THROUGH WHICH SAID ONE MANUAL SWITCH IS CONNECTED TO SAID RELAY MEANS WHEREBY A LOAD MAY BE LIFTED ONLY WHEN SAID OVERLOAD RELAY IS ENERGIZED, THE CONNECTION BETWEEN SAID OTHER MANUAL SWITCH AND SAID OVERLOAD RELAY BEING EFFECTIVE TO ENERGIZE SAID OVERLOAD RELAY UPON CLOSING OF SUCH OTHER SWITCH WHEREBY THE INITIATION OF ENERGIZATION OF THE OVERLOAD RELAY IS ACCOMPLISHED BY CLOSING SAID OTHER MANUAL SWITCH TO LOWER AN ASSOCIATED LOAD, AND A HOLDING CIRCUIT FOR SAID OVERLOAD RELAY INCLUDING OVERLOAD RESPONSIVE MEANS FOR OPEN CIRCUITING THE HOLDING CIRCUIT TO DEENERGIZE SAID OVERLOAD RELAY.