Dynamic braking system for industrial trucks

Claim 1

IN AN INDUSTRIAL TRUCK HAVING AN ELECTRIC VEHICLE PROPULSION MOTOR, DRIVE TORQUE TRANSMITTING MEANS BETWEEN THE MOTOR ARMATURE AND VEHICLE DRIVE WHEELS, A SERVICE BRAKE PEDAL, AND PROPULSION MOTOR ELECTRICAL CONTROL MEAN INCLUDING A MANUALLY OPERATED DIRECTION CONTROLLER AND SOLENOIDAL SWITCHES CONTROLLED THEREBY FOR CONNECTING THE MOTOR ARMATURE AND FIELD SELECTIVELY IN EACH OF TWO MUTUALLY REVERSED POLARITIES FOR OPPOSITE DIRECTIONS OF PROPULSION BY RESPECTIVE DIRECTION SETTINGS OF SAID CONTROLLER, AN ELECTRO-DYNAMIC BRAKING SYSTEM COMPRISING: ELECTRO-DYNAMIC MOTOR BRAKING CIRCUIT MEANS INCLUDING SAID SOLENOIDAL SWITCHES AND A MOTOR SHUNTING RESISTANCE CIRCUIT BRANCH HAVING A SHUNTING SWITCH THEREIN; AND DYNAMIC BRAKING CONTROL MEANS INCLUDING A SWITCH UNIT HAVING A NORMALLY CLOSED FIRST SWITCH AND NORMALLY OPEN SECOND SWITCH, SAID UNIT BEING ACTUATED TO NON-NORMAL SWITCH SETTINGS BY DEPRESSION OF SAID BRAKE PEDAL, SAID FIRST SWITCH WHEN OPEN CUTTING OFF POWER THROUGH SAID CONTROLLER AND THEREBY TO SOLENOIDS OF SAID SOLENOIDAL SWITCHES CONTROLLED THEREBY, A DYNAMIC BRAKING POLARITY SELECTOR CIRCUIT INCLUDING SAID SECOND SWITCH AND SELECTOR SWITCH MEANS MECHANICALLY CONNECTED TO SAID CONTROLLER TO SELECTIVELY ENERGIZE THE SOLENOIDS OF SAID SOLENOIDS SWITCHES UPON CLOSURE OF SAID SECOND SWITCH FOR A MOTOR POLARITY OPPOSITE THAT ATTAINED FOR PROPULSION BY A PREVAILING CONTROLLER SETTING, AND MEANS CONTROLLED BY SAID SWITCH UNIT FOR OPENING SAID SHUNTING SWITCH WHEN POWER IS SUPPLIED TO SAID CONTROLLER AND FOR CLOSING SAID SHUNTING SWITCH UPON ACTUATION OF THE UNIT.