Bend Pulley

A bend pulley redirects the conveyor belt within the system structure — typically used to change the belt path direction at corners, transitions, or take-up arrangements. Unlike drive or tail pulleys, bend pulleys transmit no torque and carry no material load; they exist purely to guide the belt along a defined geometric path. Common applications include redirecting the return strand around a gravity take-up frame, guiding the belt around a conveyor structure corner, or routing the belt through a multi-directional system layout.

Minimum bend pulley diameter depends on the belt carcass type (EP, NN, or Steel Cord), strength class, and whether the bend introduces a standard or reverse bend to the belt. Standard bends — where the belt curves in the same direction as the carrying side — have a lower minimum diameter requirement than reverse bends, which stress the carcass in the opposite direction. The minimum diameter is read from ISO/DIN lookup tables based on belt type and rating, then confirmed against the geometric requirements of the installation.

Bend pulleys contact either the belt's carrying surface or its return face, depending on their position in the system. In either case, adding lagging would increase the friction force on the belt surface without providing any functional benefit — bend pulleys do not need traction. A smooth machined steel shell is preferred, as it minimises resistance to belt movement and reduces wear on the belt surface at the contact point. Lagging also increases the effective pulley diameter, which must then be recalculated against the minimum diameter requirements.

Both are non-driven deflection pulleys, but they serve different purposes. A snub pulley is positioned specifically near the drive pulley to increase the belt wrap angle and improve drive traction — its position and angle are calculated to achieve a target wrap angle at the drive pulley. A bend pulley is used anywhere else in the conveyor circuit where the belt path must change direction, such as at take-up arrangements or geometric routing constraints. Snub pulleys are typically smaller and positioned to maximise wrap angle; bend pulleys are sized for the deflection angle and belt tension at their specific location.

The radial load on a bend pulley shaft is determined by the vector sum of the belt tensions on both the incoming and outgoing belt strands. For a small deflection angle, the resultant load is low relative to the belt tension. As the deflection angle increases toward 180°, the resultant load approaches twice the belt tension. This means that bend pulleys placed at sharp direction changes carry very high bearing loads relative to their size, and bearing selection must explicitly account for the deflection angle rather than using a simplified approximation.

Bend pulleys require periodic inspection of the shell surface for wear or material buildup, bearing regreasing at recommended intervals, seal condition checks, and verification that the pulley remains correctly aligned with the belt path. Because bend pulleys are often located in less accessible parts of the conveyor structure — inside take-up frames or at structure transitions — they are frequently overlooked during routine maintenance. Bearing failure at a bend pulley can cause belt misalignment and unexpected downtime, so including them in a structured preventive maintenance programme is important.