2.2 - Rollers, technical design and data Roller body Consists of a steel tube of adequate thickness and diameter to match the required use, machined at either end to allow maximum precision in the assembly of the roller. Bearing housings are positioned at either end by welding or by deep swaging. The design of the housings, of strong and rigid construction, has been developed using a computerised system that determines their thickness in relation to the maximum load required for various types of rollers. The housing for the bearing has been studied and designed in a way that reduces the angle between the bearing and spindle caused by the deflection of the spindle under load. The positioning of the bearing in all the housings has been calibrated to the tolerance “M7” which is an optimum fit for the bearing in all working conditions. The precision bearings of radial rigidity with a spherical ball race, have a maximum play of C3 fit, which is the most suitable class of fit to guarantee perfect function under serious load conditions or where the spindle is deflected a lot. Fig. 2 This type of bearing is today the most utilised in conveyor rollers, because it has a high tolerance to axial load and a low resistance to movement and rotation. In all, together with lubrication, permanent and for life, a long working life results.

Spindle The spindle is the load carrying component of the roller and must be sized in relation to the load and the roller length. It is important not to overload the roller due to the resultant excessive deflection of the spindle which in turn places irregular pressure on the bearing, and reduces, as a consequence, the roller life. Fig. 4 - Deflection of spindle under load y = Angle of bearing deflection The high quality end machining of the roller and of the roller body, the numerically controlled welding machine, the accuracy of assembly and the live testing, are all guarantees of the optimum...

^ Rollers Rulmeca has prepared over many years a laboratory test room, with specially designed machines that permit testing to verify the designs and developments of rollers for belt conveyors. These machines allow the examination of the following characteristics for each roller type: - load capacity and life; - hermetic sealing of rollers: stationary and in rotation; In the following photos we may show some of the more important machines and equipment that are situated in the test room. - Computerised machines for load and life testing, in which load cells, digitised by signals from a personal...

Machine for the dynamic hermetic test against water or dust ingress. The seal is immersed in water or dust and the subsequent test with the roller inclined simulates the real situation of the working transom. Machines that test the resistance to rotation. Here a load cell is utilised that feeds an electronic display where the resistance values are shown, at differing speeds or with different loads applied to the roller. Tests are carried out periodically on all types of rollers bringing together all the gained experience of testing, that allow us to constantly control our production quality and...