US Patent 9961839 Vegetation cutting device

A vegetation cutting device having a housing and a motor mounted in the housing to drive a drive gear. A rotatable eccentric cam mounted on the drive gear. A reciprocating blade assembly having a first blade and a second blade, wherein the first blade is coupled to the rotatable eccentric cam and is arranged to reciprocally move when driven by the rotatable eccentric cam. A cam adjustment mechanism for varying the eccentricity of the rotatable eccentric cam with respect to the drive gear to thereby vary the distance through which the first blade moves.