US Patent 6868919 Switching device for multifunctional hand-held machine tool

The object of the invention is a device, intended for a multifunctional, hand-held tool machine, for example, an electric combination hammer, for the ON/OFF switching or changeover of individual system functions when changing the processing mode, for example, from “hammer drilling” to “chiseling”. Pursuant to the invention, the changeover device, which is to be actuated by the user, is coupled with a mechanical driving mechanism, by which a bistable switch, comprising two mutually oppositely movable elements, is actuated. In a combination hammer, the invention guarantees that, when the chiseling operation is selected, certain functions of the system, such as a monitoring of the reaction moment, are interrupted or changed over.