The U-clip shaft collar from Amacoil Inc., Aston, Pa. (amacoil.com), slides easily in one direction onto hardened (minimum of 50 HRc) and unhardened shafts, but will not slide the other direction until users pull on the clamping ring.
Friction between the shaft and clamping ring keeps the collar in place. Typical applications include holding reels and tools in place on shafts. Holding force varies from 55 to 80 lb, depending on collar size. Collars come in six metric sizes with diameters of 19, 12, 15, 16, 20, and 22 mm. They resist corrosion and can be installed and removed without tools.