Variable speed trigger switch

A variable speed trigger switch for a power tool that is adapted to be connected to the power lines and to the motor of the tool for controlling the application of power to the motor, comprising

• a printed circuit board having first and second sides thereof and including a pair of stationary contacts one of which is electrically connected to one of the power lines and disposed on said first side of said printed circuit board, a strip of electrical resistance material also disposed on said first side of said printed circuit board, and an electronic motor speed control circuit disposed on said second side of said printed circuit board and including a semiconductor control device connected in series with said motor across the power lines for controlling the application of power to said motor and control circuit means for controlling the firing of said semiconductor control device in accordance with the position of the trigger;
• a generally rectangular-shaped clamshell-type housing having first and second halves thereof which when assembled are adapted to capture and locate said printed circuit board therebetween and further defining a trigger aperture adjacent said first side of said printed circuit board;
• and a spring return trigger slidably mounted in said housing through said trigger aperture such that the movement of said trigger parallels said printed circuit board adjacent said first side of said printed circuit board, a bridging contact carried by said trigger so as to slide over and electrically interconnect said pair of stationary contacts on said first side of said printed circuit board as said trigger is retracted and a wiper contact carried by said trigger so as to contact along said strip of electrical resistance material on said first side of said printed circuit board as said trigger is retracted.