System for controlling electric motors in power tools and the like

Claim 1

IN AN ELECTRICAL CONTROL SYSTEM, THE COMBINATION WITH AN ELECTRIC MOTOR HAVING SERIES CONNECTED ARMATURE AND FIELD WINDINGS, WHICH MOTOR IS MOUNTED IN A TOOL HOUSING HAVING A HANDLE PORTION, OF A SILICON CONTROLLED RECTIFIER IN SERIES CIRCUIT RELATION WITH SAID MOTOR AND THE SERIES COMBINATION ARRANGED AND ADAPTED FOR ENERIGIZATION FROM AN ALTERNATING CURRENT SOURCE; SAID RECTIFIER INCLUDING AN ANODE, A CATHODE AND A GATE; A SERIES CONNECTED VARIABLE RESISTOR AND CAPACITOR CONNECTED RESPECTIVELY TO SAID ANODE AND CATHODE, A CONNECTION INTERCONNECTING SAID GATE AND THE COMMON CONNECTION BETWEEN SAID RESISTOR AND SAID CAPACITOR, VARIATION IN THE RESISTANCE OF SAID RESISTOR IN SERIES WITH SAID CAPACITOR EFFECTING A CORRESPONDING CHANGE IN THE VOLTAGE AND CURRENT APPLIED TO SAID MOTOR, SAID DEVICES CONNECTED IN SERIES WITH SAID MOTOR BEING MOUNTED IN SAID HANDLE PORTION, AND A TRIGGER ON SAID PORTION CONNECTED TO SAID VARIABLE RESISTOR FOR CHANGING THE RESISTANCE IN SERIES WITH SAID CAPACITOR, MANIPULATION OF SAID TRIGGER SERVING AS THE SOLE MEANS FOR CONTROLLING THE SPEED OF SAID MOTOR.