Calculation of the behaviour of rubber-covered pressure rollers

Data are given which enable the properties of nips between metal and rubber-covered pressure rollers to be calculated from the parameters of the system. The properties with which the calculation is primarily concerned are the nip width and the mean pressure in the nip, but the principle can be extended to include the peak pressure and the distribution of pressure through the nip. The calculation is based on the well-known Hertzian formula and on empirical relations, which express the important effects of the rubber-cover thickness. The data refer not only to roller systems in which the loading is uniform, but also to non-uniform nips, in particular to those which show what is probably the commonest cause of non-uniformity, roller deflection. Although the calculations refer primarily to nips between one hard roller and one relatively soft, covered, roller, they are directly applicable to nips between two identical covered rollers and may be applied, within limits, to systems in which the rollers are dissimilar in properties.