In the field of Steel Fabrication Teflon®, PTFE and Fluorogold® are most often bonded to steel backing plates to form Slide Bearings. This type of assembly works very well when the anticipated movement will only be horizontal, such as expansion or contraction. Occasionally the application requires the bearing to also allow for some movement or cushioning vertically. In cases like these, the bearing design can have a standard thickness, sliding surface bonded to a commercial rubber cushion.
What is commonly referred to as deflection in Slide Bearing construction, is actually called “Rotation.” It is the action created when any member of the assembly moves or flexes vertically. See drawing below:
In this configuration, the Slide Bearing is constructed with a sizable thickness rubber pad bonded to the lower element. This provides for the rotation, while the mated Teflon® or Fluorogold® surfaces can still allow for horizontal expansion and contraction. It is important to note that, at moments of rotation, the two sliding surfaces always remain parallel to one another and the load of the structure remains evenly distributed.
As mentioned above the commercial grade neoprene can be any thickness desired. It can also be bonded to itself for added thickness and cushioning options. The photos below show 70 Durometer Neoprene layers, each 1” thick bonded together to form a 4” thick Neoprene bearing.
What should be considered in these cases is that typical Commercial Grade Neoprene has a maximum load capacity of 800 psi. Beyond this, it will begin to lose its shape by bulging out at the sides. As well, it will be prone to premature failure. An option for if greater maximum loads are anticipated is to use Viblon® material in place of the Neoprene.
Shown in the photo below, Viblon® is made of many layers of cotton-polyester fabric which are completely infused with nitrile rubber. This construction allows for flexibility and rotation, while developing a maximum load of 1,500 psi, almost double that of Commercial Grade Neoprene.
Viblon® is manufactured in sheets 48” wide, similar to neoprene. Standard thicknesses are 1/8”, 5/64”, 11/32”, 1/2”, 3/4”, and 1”. These can also be bonded to form thicker pads or layers of steel backing plates can be added. In each of these cases, the horizontal stability is greatly increased over standard neoprene.
