Rotary cutter for mowers

Abstract

A rotary cutter head for use with a rotating filament trimmer in which a reel for winding cords or filaments is held between a housing covering a lower portion thereof and a retainer or hub fixed on the driven rotating shaft of the trimmer unit and is rotatably disposed within the housing. Within the bore of the reel, an axially movable slider is normally biased toward the retainer by the elastic force of a spring so that meshing engagement occurs between a peripheral array of axially projecting tongues formed on one end of the slider and a plurality of radial teeth-like ribs formed on the inner side of the retainer and establishes a driving connection to rotate the reels. By applying an axial impact against the housing, the slider is moved axially by inertial forces against the biasing force of the spring to release that engagement, and axially projecting detent fingers formed around the other end of the slider press against the opposed slopes of a circular rib formed on the inner side of the housing and bring about both positive relative rotation of the reel and fix a limit to such rotation to a predetermined amount thereby to play out a limited length of fresh cords. In order that the reel may rotate in an opposite direction to rewind the cords, moreover, the radial ribs formed on the retainer and the tongues of the slider are formed with opposed cooperating cam slopes which force the slider axially until the tongues are clear of the ribs during backward rotation.