The Conidrive Series of timing-belt drives from Stock Drive Products, New Hyde Park, N.Y. (sdp-si.com), features offset conical projections on the bearing surfaces that match with depressions on the bottom of the belts.
These ensure a positive fit without guides such as pulley flanges, even for narrow belts. The 10-mm pitch belts are bidirectional and polygon free, so they roll smoothly around pulleys. And uniform force distribution on the belts eliminates lateral forces. The belts, made of polyurethane with steel tensile-cord reinforcements, move quietly and without vibration.