Mines Rely on British Couplings

11th Feb 2008

British couplings manufactured in the Yorkshire town of Halifax, by Renold Hi-Tec, are providing failsafe operation and protecting men and equipment in mining applications around the world. Fitted to the pit-head winder, hoisting men and coal, the inherent failsafe nature of Hi-Tec's rubber-in-compression couplings ensures that whatever the circumstances the winder will still be able to operate.


Rubber-in-compression couplings are comprised of two round, metal sections fitting one inside the other with what looks like the paddles of a paddle steamer projecting inwards from the outer section and outwards from the inner. Rubber blocks are placed in the spaces in-between the paddles, and, as the outer section is turned by the engine, it drives the inner section through the rubber blocks. As this happens the rubber is compressed, hence the term 'rubber-in-compression.'

When rubber is loaded in compression it behaves as an incompressible fluid and is inherently much stronger than the alternative technology of rubber-in-shear, or tension, where the slightest scratch in the rubber can lead to catastrophic tears and complete coupling failure. RHC's rubber-in-compression couplings are intrinsically failsafe because even if the impossible happened and the rubber blocks vaporized, the strong metal paddles would come together to provide the drive. In many applications coupling failure is not an option and rubber-in-compression couplings are often specified because of their failsafe qualities.

This type of coupling is also maintenance free and does not require lubrication or adjustment of any kind, which means that it provides the lowest lifetime cost on all applications. The only serviceable items are the rubber blocks which in most cases are good for over 10 years of service. They are also very robust and ideally suited to more arduous applications where the rubber blocks in the coupling dampen the shock loads and reduce the vibratory torque in the drive train.

For reasons of safety and reliability Renold's rubber-in-compression couplings are also fitted on key capital plant such as longwall shearers, armoured face conveyors and dint headers where reliability is essential to maintain high levels of production.