The new double-cardanic coupling design compensates for not only a greater range of shaft angle offsets, but also a considerably greater radial offset so that shaft ends can be connected in a manner that offers the drive greater protection.

With this two-joint version, compensation for radial offset that occurs between the shaft ends is enabled by a corresponding angle of inclination in the elastomer joints. This increases the range of possible radial offset by more than a multiple of four. Shaft ends that are not 100% in alignment present a significant problem especially in pump applications. In such cases the N-EUPEX DK provides a solution for many problems. Depending on the coupling length and size, it enables compensation for a radial offset of up to 3 mm.

In contrast to the previous N-EUPEX, the new coupling type "DK" makes use of not just one, but two series of elastomer elements, which guarantees increased damping over the entire drive train. Significantly lower restoring forces are generated due to the double-cardanic design. The high ratio of shaft and joint clearance also decreases the restoring forces. Depending on size, offset and installation dimensions, the restoring forces decrease by more than half. The result is a lower load on the shafts and the bearings. This is advantageous especially with thinner shafts, which can be damaged due to the wrong coupling design or improper installation, even up to the breakage point. The spacer, made of aluminium with a joined pocket part made of grey cast iron, comes in standard increments for shaft spacing from 100 mm to 250 mm, therefore length can be adapted to the application requirements.

A further design feature is the complete encapsulation of the elastomer elements. The covering prevents the sleeve from flying off if components break due to improper overload. In contrast to other solutions on the market, the elastomer elements are located outside of the shaft diameter instead of within it. Greater distance from the axis of rotation means lower load on the outer wall therefore less wear. This clearance plus the decreased tendency of the 90 Shore A elements to undergo working in case of shaft offset means the elements have a longer service life.

Good compromise between damping and rigidity is achieved with the use of 90 Shore A elastomer elements. Two springs connected in a series significantly reduce torsion spring rigidity.

The N-EUPEX DK has a plastic cover on both sides of the spacer to prevent steel-to-steel contact in case of axial displacement. The cover also provides dust protection.

Type DK couplings in the size range from 68 to 225 are appropriate for long and trouble-free operation, particularly for pump applications, because they enable compensation for large shaft offsets as a consequence of thermal expansion, for example. Due to very low restoring forces, the coupling provides a smooth solution in difficult and demanding cases.

Suitable for use in potentially explosive areas.  ATEX certification on request.

Link to technical specification catalogue: https://www.jbj.co.uk/e-publications/N-Eupex-torsionally-flexible-couplings-available-from-jbj-Techniques-Limited/34/index.html

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