This European Standard deals with the requirements for the design and manufacture of spherical and cylindrical PTFE bearings. The requirements and properties of the curved sliding surfaces are included in EN 1337-2.
Spherical and cylindrical bearings with an included angle 2 ? > 60° and 2 ? > 75° respectively are beyond the scope of this European Standard. (see Figure 6).
For the purpose of controlling the degree of freedom the bearings may be combined with flat sliding elements and guides according to EN 1337-2:2004 and restraining rings as per 6.3.4.
Cylindrical bearings are susceptible to unexpected moments about the transverse axis of the cylindrical surface.
Additional limitation of application to be taken into consideration is given in clause 1 of EN 1337-2:2004.