PTC SPHERICAL BEARINGS

Bearings are the most advanced and sophisticated support bearings available, providing
complete structural freedom in rotation and horizontal sliding.
All PTC bearings are manufactured in accordance with BS 5400: Section 9.2:1983.

Material specifications

The PTC spherical bearing bases and rockers use maintenance-free aluminium alloy.
Sliding plates are made of structural steel, faced with high quality stainless steel.
Sliding surfaces are lined with pure PTFE to BS 6564.
Pins for side restraints are special spring steel with minimum yield strength 1100 N/mm².
All permanently exposed steel parts are fully corrosion protected. Several different treatments are available, full technical data on request.
Full details of material specifications are available on request.

Design

Sliding friction
The friction coefficient for PTFE is not constant but decreases with increasing direct stress. PTC bearings are permanently lubricated to reduce the static coefficient of friction.

Lateral restraint
It is emphasised that only one PTC spherical bearing at a support should be provided to resist a full transverse force, because it is not possible to position two bearings in a rigid structure to guarantee that such a force will be shared equally between them. Also, adequate vertical load must be present to ensure stability. We recommend consultation with our Engineer.

High rotation
± 3° (0.052 radians) in any plane. More than adequate for most structural purposes.

Removeability
All bearings are designed to be removable with minimum jacking of the structure.

Contact stress
The average base contact stress of the bearings illustrated approaches 17.5N/mm2. Direct contact between the aluminium parts of the bearings and dissimilar metals must be avoided.