US Patent 7954243 Hair cutting apparatus

Hair cutting apparatus having at least one cutting unit (2) with a stationary cutting member (3) and reciprocable movable cutting member (4) each having cooperating bearing surfaces (7,8) with cutting edges (9,10). To minimize the friction between the bearing surfaces a visco-elastic element is provided between the coupling element (14) and the movable cutting member (4) resulting in a small cutting gap between the bearing surfaces. During cutting of hairs the visco-elastic element behaves as a stiff element whereas during periods in which no hairs are cut the element behaves relatively soft so that the cutting gaps between the cutting edges are closed.