Guide bar oiling system for chain saw

Claim 1

In a chain saw having a power head with a support surface to receive a guide bar, a guide bar having an inboard end portion, means for removably securing the inboard end portion of said guide bar to the power head of the chain saw in a position overlying said support surface, said guide bar having at its periphery two peripherally extending side flanges defining betweem them a peripherally extending groove, a saw chain running on said guide bar and comprising links having support surfaces sliding on outer edges of said side flanges to support the chain on the guide bar and links with tangs extending into said peripheral groove of the guide bar a distance less than the depth of said groove and slidably engageable with an area of the inner surface of each said side flange extending in from the outer edge of said flange a distance equal to the inward extent of said tangs, said guide bar having in its inboard end portion an oil hole extending through one said side flange and opening into said peripheral groove, the inner end of said oil hole opening in the inner face of the respective side flange wholly within the area thereof engageable by said tangs and the diameter of the inner end of said oil hole where it opens into the groove of the guide bar being between one thirty-second inch and one-eight inch, and means on said power head for supplying lubricating oil under pressure to said oil hole to lubricate said chain, including a recess in said supporting surface in position to communicate with said oil hole and an oil supply passage communicatIng with said recess, the cross sectional area of said oil hole varying within the thickness of the respective side flange so as to have a larger cross sectional area at the outer face of said side flange for communication with said recess than at the inner face of said side flange, said tangs sweeping the inner end of said oil hole to inhibit clogging of said oil hole by sawdust or other particles.