Trimmer Head with Automatic Trimmer Line Feed Mechanism

A trimmer head assembly, comprising:

• a housing having a base and a peripheral wall that extends from said base, wherein said housing defines an interior, and wherein string line openings are disposed in said peripheral wall;
• a spool positioned within said interior of said housing, said spool having a top flange and a bottom flange;
• a cam guide formation disposed atop said top flange of said spool, wherein said cam guide formation defines a pathway of a complex shape;
• a cam arm mounted to said housing at a pivot connection, said cam arm having a cam projection extending therefrom that extends into said pathway of said cam guide formation;
• and
• a spring for biasing said cam arm about said pivot connection and into a first orientation, wherein said complex shape of said pathway enables said cam projection to move only in a first direction along said pathway when said cam arm is in said first orientation;
• wherein said cam arm moves about said pivot connection from said first orientation to a second orientation when said trimmer head assembly is rotated above a predetermined rotational speed, wherein when in said second orientation, said complex shape of said pathway enables said cam projection to move only in a second direction along said pathway that is opposite said first direction.