Chain saw safety method and apparatus

Claim 2

A chain saw adapted to be held by an operator using both hands comprising: a frame having, a frame handle and a control handle; a guide rail connected to said frame; a cutting chain operably carried by said guide rail; power means mounted on said frame and operably connected to said cutting chain for driving said cutting chain on said guide rail; self-locking brake means operably connected to said cutting chain for stopping movement of said cutting chain on said guide rail, said brake means including, a generally cylindrical brake drum operably connected to said cutting chain; at least one arcuately wedge-shaped brake shoe operably carried adjacent the periphery of said drum and normally held away from engagement therewith; and at least one stationary frame lug fixedly connected to said frame and positioned adjacent said at least one brake shoe; and brake actuation means connected to said brake means and having a portion thereof operably positioned adjacent to said frame handle for actuating said brake means and stopping cutting movement of said cutter chain in the event an operator''s hand accidentally slips from said frame handle toward said cutting chain.

Claim 3

A chain saw as defined in claim 1 wherein: said at least one arcuately wedge-shaped brake shoe comprises: a pair of diametrically shaped brake shoes, pivotally supported upon a yoke connected therebetween; and said at least one stationary fRame comprises: a pair of frame lugs each one positioned on said frame adjacent a corresponding one of said pair of brake shoes.

Claim 4

A chain saw safety device, adapted to be attached to a chain saw of the type having a frame with a frame handle and a control handle, a guide rail, a cutting chain and power means mounted on the frame and operably connected to the cutting chain for driving the cutting chain on the guide rail, comprising: a brake system including, a generally cylindrical brake drum operably connected to the cutting chain, at least one arcuately wedge-shaped brake shoe operably positioned adjacent to but normally spaced from the outer periphery of said drum, and at least one stationary frame lug fixedly connected with the frame and positioned adjacent said at least one brake shoe to serve as an abutment when said shoe is actuated against said drum; a brake casing connected to the chain saw frame; and a yoke pivotally mounted within said brake casing and lying adjacent to said brake drum, said yoke being operable to carry said at least one arcuately wedge-shaped brake shoe; and an actuation system including, a bail handle pivotally mounted adjacent the frame handle and having a safety bar portion disposed generally parallel with the frame handle and positioned between the frame handle and the cutting chain; and a push rod connected at one end to said bail hand and connected at the other end to said yoke, whereby actuation of said push rod pivots said yoke within said brake casing for actuating said at least one arcuately wedge-shaped brake shoe between said at least one stationary frame lug and the outer periphery of said generally cylindrical brake drum to immediately stop rotation of said drum and movement of the cutting chain.

Claim 5

A chain saw safety device, adapted to be attached to a chain saw of the type having a frame with a frame handle and a control handle, a guide rail, a cutting chain and power means mounted on the frame and operably connected to the cutting chain for driving the cutting chain on the guide rail, comprising: a brake system including, a generally cylindrical brake drum operably connected to the cutting chain, at least one arcuately wedge-shaped brake shoe operably positioned adjacent to but normally spaced from the outer periphery of said drum, and at least one stationary frame lug fixedly connected with the frame and positioned adjacent said at least one brake shoe to serve as an abutment when said shoe is actuated against said drum; a brake casing connected to the chain saw frame; and a yoke pivotally mounted within said brake casing and lying adjacent to said brake drum, said yoke being operable to carry said at least one arcuately wedge-shaped brake shoe; and an actuation system including, a bail handle pivotally mounted adjacent the frame handle and having a safety bar portion disposed generally parallel with the frame handle and positioned between the frame handle and the cutting chain; and a push rod connected at one end to said bail hand and connected at the other end to said yoke, whereby actuation of said push rod pivots said yoke within said brake casing for actuating said at least one arcuately wedge-shaped brake shoe between said at least one stationary frame lug and the outer periphery of said generally cylindrical brake drum to immediately stop rotation of said drum and movement of the cutting chain.