(57) An anchor in a chain saw guide bar digs into the sidewall of a kerf as soon as kickback
begins, to stop kickback of the guide bar while it is in the kerf. The anchor does
this with a laterally projecting, impaling fluke mounted to the bar and biased towards
its projecting position through a torsion spring contained completely within the bar.
Bends in the torsion spring about longitudinal axes increase the bias angle of the
fluke relative the kerf. Bumper faces of the fluke permit entrance of the fluke into
the kerf and movement within the kerf in the longitudinal and downward directions
by the fluke displacing towards the bar. A stop pivot adjacent the side of the guide
bar opposite that from which the fluke extends, engages the fluke, prevents downward
deflection of the fluke when it experiences kickback forces, and provides an off-center
pivot for the spring to force it to resist deflection by torsion. A lateral limit
stop applies a preload torque to the fluke to torsionally load the spring so that
the spring urges the fluke outwardly. A retractor cam adjacent the fluke, when operated,
draws the fluke within the guide bar for unusual cuts.
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