Washers & Bushings

Washers & Bushings

Washers and Bushings are used to isolate or insulate bolts and anchors

Rubber pads such as Bellcell or reinforced rubber materials like Bellpad are commonly used as vibration isolators under machinery and equipment.  In many cases, the equipment or machine is anchored to the floor or bolted to a structure.  Vibration isolation washers and bushings are used in these connections to avoid any vibration from being transmitted through the bolted connection.  If vibration passes through the bolt, it reduces the effectiveness of the vibration isolation material.

Vibration isolation washers and bushings work together with the vibration isolation material to provide a greater overall degree of vibration isolation.  Isolation washers are used under the steel washer in the connection preventing metal to metal contact and breaking the vibration path.  Isolation bushings (sometimes called bolt bushings) are installed around the bolt or anchor for the same purpose.

Isolation washers and isolation bushings made from rubber and PTFE can also be used as bolt insulators.  The electrical properties of these materials such as dielectric strength, allow for them to be used as electrical insulating sleeves and insulating washers around bolted connections. 

Washers can be made integral to bushings and sleeves as one unit.  When supplied this way, they are also called flat headed sleeves or flange washers.  In addition to being used for vibration isolation and electrical insulation, these materials are also used to prevent galvanic corrosion between dissimilar metals in structural connections.