Design and Materials

PTFE is the now-familiar, low-friction material used in the slip plane in many designs of structural bearings. This material possesses the attractive feature of a reduced coefficient of friction with increasing loads. But in sheet form, the tensile strength of 2800 psi limits the loading allowed.

Bearings designed with this material, therefore, must achieve a compromise between high unit loading and cold flow. Fillers can reduce cold flow, but they increase cost and the coefficient of friction, both of which are undesirable.

“TeXLon™” is the trade name for Cosmec’s 100% PTFE matting. PTFE fiber has a tensile strength nearly 16 times that of pure PTFE sheet material, and therefore, TeXLon™ can sustain far greater working loads without cold flow. The higher strength is inherent in the spun yarn and does not depend on any filler material. TeXLon™ is pure PTFE, not a woven composite.

TeXLon™ has a minimum thickness of 0.05” after compression and is mechanically interlocked to a rigid substrate. The interlock pattern is equally distributed over no less than 25% of the bearing area and is of sufficient profile and strength to withstand 10% to 20% of the vertical unit load applied horizontally without consideration of the effect of supplemental adhesive. The PTFE resin from which the fabric material is produced is virgin material that meets the requirements of ASTM D4894.

Stainless steel is 16 ga. minimum thickness conforming to ASTM A240 Type 304 or Type 316 with a maximum surface finish of 20 RMS. Major carbon steel components are ASTM A709 Grade 50 (AASHTO M270 Grade 50) steel, and ASTM A709 Grade 50W (AASHTO M270 Grade 50W) weathering steel, or ASTM A709 Grade 36 (M270 Grade 36) will be considered on demand.

All materials for all US bearings will be certified domestic material, manufactured and fabricated in the USA in accordance with the “Buy American” requirements for all federally funded work.

Testing can be undertaken to fulfill all requirements of the AASHTO Specifications and any other specialized testing as may be required. Most testing can be performed in our own testing facilities.

Coating on the bearings can be the latest high-performance paints, including high-solids zinc primers, or the bearing assemblies can be metallized (zinc or zinc/aluminum thermal spray coatings). Galvanizing of the carbon steel components can be considered on demand. Coating recommendations can be made to ensure a long-lasting product, no matter the environment.