Keyless shaft to hub connections are known as locking bushes, locking assemblies, locking elements, bushings and friction joints. All use friction to connect from a shaft to a hub, sprocket, pulley, gear, etc, without the need for keyways, steps, splines & collars. The main advantages are ease of setting, easy dismantling, lower machining costs and a backlash free connection without fretting. Locking bushes transmit torque and also radial & axial loads within rated limits.
Mechanical locking bushes are manufactured by the specialist Tollok. A number of axial bolts are tightened to expand tapered cones which grip the shaft and hub. The market for mechanical locking bushes has diversified and there are now many different designs to suit niche applications. Shaft diameters are 6 to 900mm and compared to hydromechanical bushes, these designs tend to be lower in cost but slower to fit. In addition Tollok manufacture shrink disc locking bushes (compression couplings) which are ideal to connect hollow to male shafts. These are available for shafts 12 to 620mm.
ETP are specialists in the design and manufacture of locking bushes with hydromechanical principles, for example the ETP classic bush which was inverted 40 years ago. The products now suit shafts from 6 to 220mm, mostly using the principle of compressing a pressure medium that expands the inner and outer walls of the bush. The advantages are easy setting, particularly with the single screw versions such as ETP-Express, and reliable fast disassembly.