Patent ID: 6049460
Filing Date: 2000-04-11
Classification: H01H

Abstract:
A trigger actuated control for controlling rotational speed of an electric motor of a portable tool, said control having:an electrically insulating housing;a manually displaceable trigger mounted to said housing;an electric circuit in said housing comprising a variable resistor operably connected to said trigger and a thyristor connected in circuit with said variable resistance and the electric motor of said portable tool for varying rotational speed of said motor as a function of displacement of said trigger; anda primary heat sink in said housing thermally coupled with at least said thyristor;wherein the improvement comprises:an opening in said housing;a supplemental heat sink disposed externally of said housing and having a projection extending through said opening into thermally coupled relationship with said primary heat sink; andcomplemental attachment means on said housing and said supplemental heat sink for attaching said supplemental heat sink to said housing.