Sliding Sheet PTFE Spherical Bearings

VHC spherical Bearings are capable of with standing the high loads and movements suitable for structures requiring the rotary angle equal   or bigger than 0.015 rad in all directions. VHC spherical bearings are designed and manufac- tured according to current standards such as: TCVN 11823, AASHTO LRFD, ASTM D5977, EN1337 To ensure the long-life durability, VHC spherical bearings are protected against corrosion by the following methods: coating with two-component epoxy, PU-based painting (Polyurethane), hot dip galvani zation according to ASTM A123 standards and especially the Al –Mg spray coating method (at the ratio of 5% Al and95% Mg) which ensure the anti-corrosion durability of upto 100 years, this method is proved by the salt-spraying test in6000 hours (8-hour dry-wet cycle) according to ASTM B117   VHC spherical bearings possess a concave lower part (6) which has a PTFE sliding sheet (4) on it is upper curved surface. A convex calotte (5) is placed on top of this, which, thanks to it is polished hard-chromium plated surface, can slide within the lower part with low friction, thus facilitating rotations about every axis A second sliding sheet of PTFE (4) is recessed into the upper surface of the calotte. Together with the top plate (2) above it, this accommodates longitudinal and/or transverse sliding movements of the superstructure, if required. To reduce sliding resistance to a minimum, the lower surface of the top plate features a polished stainless steel sheet In the case of bearings which should allow movement along one axis only, the direction of movement is controlled by guide bars (3). In the case of fixed bearings, the top plate do not have stainless steel sheet. The bearing is connected to the superstructure and the substructure by means of anchor dowels (1)   or threaded sleeves (depending on design), or alternatively by means of separate anchor plates with shear studs