Introduction

Disc bearings have now been in use for nearly 40 years. Originally, disc bearings were a patented product produced by only one manufacturer. But in the last few years, Cosmec began to offer disc bearings to all of our bearing customers. Cosmec disc bearings are presently in use in many varied bridge structures throughout the USA.

Disc bearings offer lower profiles than other multi-rotational bearings, such as pot bearings. This is due to the use of a polyurethane disc to accommodate rotation instead of a confined elastomer, a pot, and a piston.

Figure 1 illustrates the complete disc bearing system. However, unlike pot bearings, disc bearings do exhibit compression in varying amounts under load and are, therefore, not as well suited for use where differential compression (vertical deflection) from bearing to bearing may be of some concern.

Disc bearings can be confidently used where all anticipated rotations of the bearings do not exceed 0.030 radians. In addition, disc bearings may be the product of choice when large vertical load-carrying capacity is needed, but the available room is at a premium. Also, due to their simplicity, durability, and minimum number of parts, disc bearings are very low maintenance.

Expansion disc bearings feature slide interfaces of PTFE/stainless steel. This sliding interface offers a low coefficient of friction and thus the ease of movement for the structure. Guided expansion disc bearings use guides, also employing slide interfaces of PTFE and stainless steel.