Engineers at Reliance Precision Ltd. of Huddersfield, UK were unable to find a one piece flexible coupling with high torsional stiffness, low transmission of error and excellent flexibility characteristics and so set out to fill this gap in the market themselves.

The result was the new Reli-a-Flex® couplings (patent pending)which have been developed and manufactured in-house at Reliance to perform in increasingly demanding applications. The range consists of a precision and a compact coupling, both of which are made from low inertia grade 7075-T6 aluminium which is alocromed for superior corrosion protection.

In certain applications where a three piece bellows coupling has previously been the only choice, engineers will now be able to use the one piece Reli-a-Flex®, due to its unique slit beam which gives higher torsional stiffness than other similar one piece couplings.

Reli-a-Flex’s slit pattern gives very good kinematic transfer of motion. It has radial rather than spiral slits and therefore introduces negligible axial and radial bearing loads, vital for both increased bearing life and accuracy.

The shorter, compact coupling differs from many one piece couplings of its size in that it has two sets of slits. The second set introduces an equal and opposite angle that allows it to cater for parallel as well as angular offsets (Double Hooke's joint principle).

The coupling has been extensively tested at Reliance and has completed 50,000,000 test cycles at 2.0 Nm and 0.2 mm offset without failure (RCL20).

http://www.reliaflex.co.uk/products/couplings.htm