Patent ID: 7658237

Claim:
A power tool comprising a motor for driving a tool; at least one switching element; a controller coupled with said at least one switching element for activating said motor, the controller controlling said motor so as to allow an activation of said motor for driving the tool only when said at least one switching element is activated several times in a predetermined way; wherein said controller is configured for generating at least three operating modes of said motor, a first inoperative mode, in which said motor is out of operation, a second working mode in which said motor is driven for driving a tool, and a third intermediate mode, in which further activation of a switching element is needed for transferring said motor into said working mode; said controller being configured for supplying periodic voltage pulses of a certain duration and a certain repetition frequency to said motor, when being in said intermediate mode, said duration and repetition frequency being selected so as to effect a periodic power-on and power-off of said motor, each power-on followed by an idle time and each idle time followed by a power-on of said motor; each power-on and each idle time within said intermediate mode being long enough to be perceived by a user of the power tool; said periodic power-on and power-off of said motor effecting a repetitive sequence of short movements of said power tool, without any manipulation of any switching element, for the duration that said motor is in said intermediate mode for signaling to the user that said power tool is within said intermediate mode.