Abstract: A half wave and full wave energization system for permanent magnet D.C. motors employing a hand trigger operated switch which commutates terminals of a full wave rectifier bridge when connected to a source of A.C. supply to provide selectively half wave and full wave energization of such motors when the trigger is depressed from an extended "off" position.

Abstract: A manual switch for portable electric tools having minimum parts and ease of assembly. The switch is of the trigger actuated type and includes a single-piece molded housing, single-piece stationary contact-terminals, single-piece movable contact-terminals, and a snap-in assembled trigger. The double-pole stationary and movable contact-terminals are placed in slots in the single-piece molded housing member, this molded member is folded to form a switch housing, the return spring is inserted into the groove in the trigger, the cam end of the trigger along with the spring is inserted into the housing, the housing is closed by the rivet, and the trigger is snap-in assembled fully into its hole in the housing to complete assembly of the switch. The switch is connected to a tool motor circuit by pressing electrical conductors into holes in the bottom of the housing. These connections can be released by inserting a release tool alongside the lead, or by depressing built-in release buttons in an alternate design.

Abstract: Trigger operated snap-action switches having selectable and adjustable cam inserts in the trigger arranged for engaging the plunger of a snap-action mechanism to afford selection and adjustment of the pre-travel, and in the case of a double pole switch, to afford simultaneous or sequential closing of the contacts as desired.

Abstract: A trigger switch for a portable electric tool providing substantial pretravel of the trigger before closing force is applied to the contacts. This is a safety measure to prevent the motor from starting if the trigger should be accidentally pressed in handling a circular saw or the like. The pretravel is provided by a telescopic joint between the trigger and contact carrier, each of which is biased independently by a return spring to insure immediate reopening of the contacts upon release of the trigger.

Abstract: A portable tool double-pole trigger switch enclosing a speed control circuit that includes a plastic pack SCR (semi-conductor controlled rectifier) of the sensitive gate type, a capacitor and a variable resistor. In a first version, the mounting tab of the SCR is soldered to a connector that is contacted by the resistor slider. A ceramic capacitor may be used by soldering its leads between the cathode and gate terminals of the SCR, the mounting tab serving as the anode terminal. A chip capacitor may be used by soldering it to bridge the cathode and gate terminals. In another version, the mounting tab may be arranged to be contacted directly by the resistor slider, thus eliminating the aforesaid connector.