The present invention relates to a saw chain and particularly to a saw chain having improved operating safety features.
An important aspect of saw chain design relates to ease and safety of operation. Saw chains may be provided with safety links or guard links adapted to avoid "kick back" and roughness of operation encountered when the upper part of the saw engages branches or brush, or when a cutter link becomes seized in the saw kerf. A chain of this general type is illustrated in Carlton U.S. Pat. No. 3,180,378 wherein a guard or camming surface is provided on a drive link or on a side link preceding a chain cutter link. More recently, a guard link has been suggested having a tail extending in overlapping relation to the depth gauge on the following cutter link wherein the guard link pivots outwardly as the saw chain rounds the curved end of the saw bar. This type of link is illustrated in Goldblatt U.S. Pat. No. 4,133,239. While reducing problems associated with kick back to a degree, this type of configuration has the disadvantage of deleteriously affecting the cutting ability of the chain, particularly in boring with the nose end of the bar of a chain saw. Moreover, because of the overall sloping or cammed surface of a long tail guard link, energy must be expended in camming wood chips towards the bottom of a kerf being cut and undesired angular movement of the guard link may result.
USPTO Backgrounds
USPTO Backgrounds