Kickback-free saw chain

Claim 1

A saw chain comprising a series of center links and pairs of side links pivotally joined to form an articulated chain; certain of said pairs of side links being cutter pairs comprising a non-cutting tie link on one side of the chain and a cutter link bearing an upstanding depth gauge at the front of the link and a cutter tooth comprising an upstanding shank portion and a laterally projecting toe portion rearward of the depth gauge; the pair of side links immediately preceding each cutter pair being a safety pair comprising a non-cutting tie link on the same side of the chain as the following cutter link and a non-cutting safety link on the opposite side of the chain from the following cutter link; said safety link comprising an upstanding cam portion having an upwardly and rearwardly inclinded leading edge and a rearwardly projecting tail, said tail being configured to pivot outwardly as the chain traverses the rounded nose of a saw bar to reduce the effective depth gauge setting of the following cutter to a value less than one-half the normal depth gauge setting when the chain is travelling along the straight portion of the saw bar, the upper surface of the tail of the safety link being a continuous, smooth curve having a radius of curvature from 1.7 to 2.2 times the pitch length of the safety link, the length of the tail of the safety link being at least approximately equal to the pitch length of the following center link.