RUBBERFIX pulleys have been developed using a high degree of security in the dimensioning of the flanges, in the sizing and penetration of the welding and in the assembly between the shell and pulley end disc. The conveyor pulley shells are one-piece rolled with a single seam weld. The fabrication is accurate in concentricity. All of the shells are static balanced or can be dynamic balanced if required.
All conveyor pulley shells are seam welded by MIG process. Continuous wire feeds are employed during the welding process, utilizing an inert gas atmosphere, which guarantees the maximum uniformity and resistance of weld. Well equipped workshops with advanced machining facilities ensure high quality finishing of all conveyor pulley components.

Pulleys may be cylindrical or machine crowned to aid belt tracking. If required all components can be normalized after machining or welding, for internal stresses to be eliminated and to facilitate assembly and in turn disassembly, and also to eliminate reasons for cracking or deforming under load. Shafts are normally manufactured from high strength steel bar K1045 or 4140. Rubberfix Conveyor Engineering Pty. Ltd. also fabricates pulleys from a cylindrical shell with extra strong wall and end discs which are fully welded according to AS 1554 Part1-SP. The shell is attached to a continuous shaft using locking elements and the completed assembly is mounted in external bearing housings.

The locking element used for disc to shaft attachment provides a demountable shrink fit ideal for maintenance purposes. Due to accurate control of the fit, coupled with the absence of any notch effect, the resulting stress concentration produced by the locking element is very low.

The pulley shell and shaft assembly is designed as an integral unit, where the stresses imposed in each component as a result of the belt tension, angle of wrap, pulley rotation and overall pulley dimensions (diameter, face length and bearing centres) are all assessed. The permissible stress levels are restricted within the pulley, in order to provide a satisfactory fatigue life based on Rubberfix design and manufacturing techniques.

To avoid stress raisers at the hub connections, each end disc is fabricated from a single plate, such that the thickness of the disc is at least equal to the width of the locking element. The outer edge of the disc is bevelled as a weld preparation at approximately 40-45 degrees from either one or both sides, depending upon the plate thickness.

Shafts are designed for an infinite life in accordance with Rubberfix standard design procedure, taking into account bending and torsion as applicable. All shaft calculations exclude any strengthening effect from the pulley end discs.Where there is a change in section on the pulley shaft between the locking element and the bearing seats, the shaft diameter at the bearing will not be less than 60% of that at the locking element and a large swept radius of approximately 3 times the half difference in shaft diameters will be employed to avoid stress concentration. The drive side locking element is sized to transmit the appropriate motor torque at start-up according to the drive configuration.