Drill hammer

摘要

An electric hand tool, preferably a drill hammer with an air-cushioned percussion mechanism (6), is proposed, in which the rotary drive, controllable via switching means (50, 60, 100, 110, 120) actuable from outside, is imparted to the tool via a safety coupling (33, 34', 37, 39; 62, 69, 70; 63, 68; 72, 79, 80; 73, 77, 78). In order that this safety coupling provides the desired safety, it must not be set too high in terms of torque. This has the disadvantage, however, that the safety coupling comes into action almost constantly when drilling with tools requiring a large torque. For this reason, according to the invention the moment of release of the safety coupling can be adjusted, preferably increased, from outside via actuating means (50, 60, 100, 110, 120).