Patent ID: 8550884

Claim:
A device for sharpening the cutting teeth of a chain saw while the chain is in place on the guide bar of the chain saw, the device comprising: a frame having an upper web and first and second parallel side walls for overlying the chain and guide bar of the chain saw; an open area adjacent the center of the upper web defining a sharpening area; clamp means associated with the first side wall to secure the frame to the guide bar; second clamp means associated with the first side wall for lightly engaging the chain saw tooth to be sharpened in order to fix its position with respect to the sharpening area; a tooth stop pawl for adjusting the position of the tooth within the sharpening area, the tooth stop pawl being mounted in a sliding block received in a keyway in the upper web of the frame, the keyway being aligned with the guide bar of the chain saw and permitting only a single degree of freedom in the direction of the guide bar; a pawl member pivotally attached to the sliding block extending into the open sharpening area; an adjustment bolt associated with the tooth stop pawl and rotatably captured with respect to the frame for adjusting the position of the sliding block along the length of the keyway; first and second channels formed in the frame at an angle relative to the guide bar of the chain saw; and first and second guide means being independently removable from the first and second channels, and having bores for receiving therein a rotary burr for sharpening the teeth of the chain saw, wherein the first and second guide means comprise a tapered configuration, wherein the first and second channels comprise a tapered configuration corresponding to the tapered configuration of the first and second guide means to provide a wedge fit, wherein interfacing portions of the guide means and the channels are configured to maintain a collinear relationship of center axes of the guide means and the respective channels under operating loads upon rotation of the rotary burr to sharpen the teeth of the chain saw, and wherein each of the bores comprise an angle that combines with the angle of the respective channels to provide a specific cut angle on the tooth, and wherein each of the first and second guide means are fixedly positionable in a first position or a second position to alter the position of the rotary burr relative to the cutting teeth of the chain saw.