Chain saw safety structure
OwnerGerry A. Laidlawinventor
Life of this patent
Estimating the term…
Abstract
An anti-kickback safety structure comprising both a pivoting guard over the cutting chain and a pivotable, lockable support lever projecting to the rear from the chain saw housing, having a strap and belt for securing the support lever to the forearm of the operator. The support lever automatically provides a counter-torque to restrain a kickback when the cutting chain encounters a knot or other hard object when cutting wood, and also facilitates one-handed support of the chain saw by automatically countering the torque exerted by the weight of the chain saw.
Claims13
Chain saw safety structure, for use by an operator of a chain saw having a chain saw housing containing a chain saw motor means for driving a cutting chain mounted upon the perimeter of a chain guide projecting from the forward end of said chain saw housing, for allowing said operator to readily and safely hold and operate said chain saw with one arm of said operator and for retarding kickback of said chain saw, said chain saw safety structure being hereinbelow described with reference to operation of said chain saw in a horizontal configuration of said chain guide although operation in said horizontal configuration is not necessary, comprising:
- (a) support lever means, pivotally connected to said chain saw housing, having a principal longitudinal axis and having a length just slightly less than the length of the forearm of a typical operator of said chain saw, for allowing the forearm of said operator to exert leverage for retarding kickback of said chain saw;
- (b) lock means, connected to said support lever means and to said chain saw housing, for locking said support lever means in a fixed orientation when said support lever means is rotated to the rear of said chain saw housing to an orientation in which the principal longitudinal axis of said support lever means is at least substantially parallel to said chain guide;
- (c) securing means, connected to said support lever means, for securing said support lever means to the forearm of said operator.
The chain saw safety structure as in any one of the preceding claims, wherein said lock means comprises at least one latch hook attached to said support lever means, said latch hook having a top which is tapered in a direction substantially parallel to the principal longitudinal axis of said support lever means, said latch hook having a recess below the short end of said latch hook adapted to receive a latch pin;
- a latch pin, connected to said chain saw housing within said chain saw housing by an anchor block means for holding said latch pin in a substantially horizontal position and for allowing said latch pin to move horizontally within a limited range, said latch pin having an end portion which projects at right angles through a slot in the side of said chain saw housing, said latch pin and anchor block means being so positioned on the side of said latch hook toward which said latch hook tapers, that said end portion of said latch pin may move into said recess of said latch hook when said support lever means is extended to a substantially horizontal position to the rear of said chain saw housing;
- and a spring means, surrounding the principal portion of said latch pin, for urging said latch pin to the fully extended position.
Dependencies are inferred from the claim text.