Patent ID: 7240597

Claim:
A circular saw comprising: an annular disk-shaped base adapted to be driven about an axis of rotation and having a central hole disposed centrally about the axis of rotation; a plurality of tip supports formed along an outer circumference of said base integrally so that a gullet is defined between adjacent ones of said tip supports; a plurality of tip inserts respectively fixed to said tip supports; a plurality of openings formed through said base on substantially the same circumference of a circle so as to be equally spaced apart from each other in the circumferential direction of said base, each opening defined by an opening wall surface forming a closed, continuous loop and disposed between and apart from the outer circumference of said base and the central hole, the opening wall surface having a first straight portion, a second straight portion facially opposing the first straight portion in a generally parallel manner with the first straight portion being shorter than the second straight portion, a pair of short straight portions disposed opposite one another with the first and second straight portions disposed therebetween and a pair of generally semicircular portions disposed opposite one another, respective ones of the pair of short straight portions interconnecting the second straight portion at opposing ends and respective ones of the pair of generally semicircular portions, the first straight portion interconnecting the pair of generally semicircular portions; and a plurality of wiper tips respectively fixed to respective ones of the first straight portions on the downstream side of a rotational direction of said base; wherein each of said wiper tips having a front surface formed as a concave surface in cross section.