Modern electrical tools require special safety mechanisms in order to protect the operator of the electrical tool in the case of an unforeseen circumstance. This circumstance can, for example, consist of a blocking or a jamming of the tool. (Such a case is known to professionals in the field as “kickback.”) If no safety mechanism is present, serious injury to the operator can occur from such a circumstance. On the other hand, the intended safety mechanisms should be cost effective and easy to implement.
An approach to protecting an operator has already been disclosed in the German patent publication DE 10 2004 004 170 A1/Aug. 18, 2005 with the title “Method for Switching Off an Electrical Power Tool in the Case of a Blockage and Electrical Power Tool”. According to this approach, the detecting of the “kickback” case is, however, limited to an evaluation of the rotational speed. This merely offers a limited safety function because an evaluation of this type cannot be flexibly applied to different usage environments and furthermore is also cost intensive as a result of many parts being needed for detecting the rotational speed.
USPTO Backgrounds
USPTO Backgrounds