Currently the typical pulley system used in the bulk materials handling industry features pillow block bearings and a rotating shaft. These pulleys are referred to as “live shaft” pulleys and are typically utilised on all driven pulleys – that is, those pulleys directly connected to the powering system.

Every component of this assembly, with the exception of the pillow block housing, rotates during conveyor operation. According to Continental Conveyor and Equipment this constant rotation can cause material fatigue – complicating both design and manufacture of the product.

Dead-shaft pulleys, such as Continental’s product, are preferred by some operators and are an alternative for non-driven pulley applications.

Dead-shaft pulleys have all moving parts internal to the pulley. The spherical bearings are located in the end discs between the hubs and the shaft – allowing rotation between the hubs and the shaft. The shaft can be held or “fixed” and no longer rotates.

“Material fatigue in the shaft is no longer an issue so design and manufacture of the shaft is somewhat simplified,” Continental said.

By virtue of their design, dead-shaft pulleys are lighter and, for comparable pulleys, their overall size is reduced. This makes them a good fit for applications such as belt storage units or tail loading sections where weight or available space is an issue.

Because the bearings are internal to the pulley, they have a shorter moment arm which translates to a smaller diameter shaft, a major cost and weight item found in typical pulleys, Continental said.

The locking assemblies and the pillow block housing are eliminated, but a bearing cover with a sealing apparatus must be added. According to the company, with a good sealing system, bearings see less exposure to the elements since they are inside the pulley.