US Patent 9770836 Blade assembly having entrapped spring

A blade assembly for a hair cutting apparatus is provided having a first blade having teeth extending along a first blade edge, a second blade positioned proximate the first blade and having teeth extending along a second blade edge parallel to the first blade edge and offset from the first blade edge by a blade gap, a yoke adapted to convert motion of a drive mechanism into reciprocation of the second blade with respect to the first blade, a spring having a spring base and at least one spring arm coupled to one of the yoke and second blade, the spring arm reciprocating with the second blade with respect to the first blade, wherein the spring arm applies a biasing force on the second blade toward the first blade to maintain the first and second blades in an operational condition when separated from the hair cutting apparatus.