US Patent 9091324 Power transmission belt and method of making same

A method of making a belt including the steps of: (a) helically wrapping a fabric strip of predetermined width on a mandrel at a first helix angle; (b) helically winding a tensile cord onto the mandrel over the fabric at a second helix angle less than the first helix angle; (c) wrapping a sheet or a strip of elastomer material around the mandrel over the tensile cord; and (d) curing the elastomer material under pressure to form a belt sleeve. The mandrel may be grooved for making toothed belts. The fabric strip may be preformed. A resulting toothed belt has a fabric seam spanning several teeth and having a helix angle. The seam may be joined.