Toothed belt manufacture

Claim 1

For use with a toothed pulley wherein the confronting flank surfaces of successive teeth are planar defining a groove having an included angle of 2θ and opening radially outwardly to a pulley circumferential surface, said groove further defining a flat bottom surface at the inner end of said flank surfaces, an improved toothed belt comprising a body portion provided with a longitudinal outer tensile member at the belt pitch line, and a plurality of longitudinally spaced teeth arranged to be successively received in the grooves of the pulley, each of said teeth being defined by transverse planar leading and trailing flank surfaces defining an included angle of substantially 2θ and having an inner end, and a tip surface extending between said inner ends of said belt flank surfaces of the tooth, said inner end of each of the planar flank surfaces in cross section being located at a point of intersection of a line perpendicular to the flank surfaces and crossing the radial centerline of the groove in the portion thereof defined radially outwardly by an outer point at the tooth root and radially inwardly by an inner point spaced inwardly from said outer point by a distance 0.5Btanθ, where B is the width of the belt tooth at the tooth root, each of the leading and trailing portions of said tip surface in cross section defining a circular segment centered on said intersection point and having a radius equal to the length of said line perpendicular to said flank surface whereby said teeth have improved engagement and disengagement relative to the pulley groove surfaces in drive operation thereof.