Power tool inertia brake

Abstract

An intertial-manual actuating chain brake for a chain saw in which a mechanical integrator distinguishes between relatively long duration accelerations developed by a "kickback" producing impulse and normal operating accelerations associated with operational and vibratory forces. Occurrence of a "kickback" impulse, developing a force of required magnitude, direction, and duration causes a spring-mass accelerometer to change from a brake released to a brake applied condition, applying a braking torque to the saw chain. The accelerometer utilizes a pivotable hand guard as the actuating means. The hand guard also provides for manual operation. The hand guard is comprised of a housing and an inertia weight that is connected to the housing. The weight and type of inertia weight can be selected to provide the brake applied condition for a predetermined movement of the chain saw or for a predetermined type of chain saw. The inertia weight can be adjusted to adjust the accelerometer.

Dependencies are inferred from the claim text.