A numerous designs and types of pulleys are proposed, to meet the great variety of uses. To meet the duties of the severest working conditions they may be supplied rubber lagged. Lagging prevents belt slippage (in particular when water is present) and increases the drive traction of the pulley. For Drive pulleys a friction lagging should always be used.

Taper friction lock assemblies allow compression shaft locking, using a system of screws and tapered sleeves, eliminating play and eccentricity ensuring the power transmission at the end disc/hub of the pulley.

Pulleys using this method of shaft locking are the most utilized today for their strength, simplicity of construction, assembly and maintenance.

Dimensioning pulleys

According to the position that they occupy in a belt conveyor, the pulleys must withstand the forces imposed by both belt tension and conveyed load. To be as efficient as possible both for replacement and for new installation, proper selection of pulleys requires the following data that allows the determination of the construction characteristics and dimension.
The principal data necessary to design a pulley comprises the following:

– belt width;

– diameter of drum in relation to the belt type and characteristics;
– locking arrangement of the shaft to the pulley (friction locking, welding);
– position of pulley (drive, return, snub, etc…);
– wrap angle of belt on pulley;
– belt tension T1, T2 or T3;
– distance between the supports and flange of the pulley “A”;
– type of lagging as required..