Hydraulic rings and propeller nuts

Time-saving SKF technology.
Traditionally, marine propellers are mounted on a tapered shaft end using a nut and key. Torque is transmitted by friction between the mating surfaces, with the key serving as a backup if the friction is insufficient.
 
During mounting, the propeller is driven up the taper by heating the propeller hub and driving wedges between the nut and the hub, by using a hydraulic press, or even by hammering the nut to achieve the required axial drive-up.
 
All these methods are time-consuming and difficult to control because of the large forces involved. For large propellers, these methods are unacceptable.
 
These conventional methods are particularly troublesome when dismounting propellers from shafts.
 
Withdrawal forces are high and damage often occurs on the contact surfaces. Because of the high forces, removal tools are often bulky, expensive and difficult to handle. The dismounting process is therefore very time-consuming.