In many cases the rolling bearings are not able to match the requirements  that are demanded  from  them, despite wide variety of types, versions and sizes. Some features of rolling bearings disqualify them from being taken into account  in the phase of defining construction principles. This features are, among others, big weight, large cross-section (bearing-closed pair size), dimension limitations (dimension series), relatively  difficult mounting  and  dismounting  and  housing onditions  (interacting  parts),  necessity  for  continuous  or periodical  supervision  –  additional  lubrication,  and  relatively high price, especially of bearings with more complex construction.  In  the  last  years  another  branch  of  bearing mounting has been considerably developed, namely plain bearings, which find even more application in all branches of modern industry.

One can divide them into two essential groups:

•  spherical plain bearings –  this group  is represented by GE-type spherical plain bearings and  rod ends of SA- and SI-type – load is carried by the pair of own friction surfaces of these bearings
•  slide bearings – one of the friction surfaces always belongs to the device interacting with the bearing – many variants are available, beginning with TUP and TUF sliding sleeves through to TUW sliding washers and sliding lates of various shapes and sizes.