Power Transmission Engineering Magazine
www.powertransmission.com/articles/4911

Ringfeder Develops Ring-flex Coupling

February 5, 2014
Whether in test stands, pumps or machining centres – more and more users are relying on torsion-proof multiple-disc couplings for the backlash-free and precise transmission of torques; and for compensating for axial, lateral and angular misalignments. Differing industries also have quite different requirements regarding the components used. In order to meet these diverse requirements, Ringfeder Power Transmission offers a wide range of Ring-flex multiple-disc couplings for use in diverse situations.

When developing the Ring-flex multiple-disc couplings, Ringfeder not only attached high importance to typical parameters such as torsional stiffness and high true-running accuracy, but also to compact dimensions and multiple connection options. Depending on customer requirements, the hubs can be attached to the shafts by means of keys, clamping hubs, shrink discs or locking assemblies. All models are available as single or double Cardan types. For double Cardan couplings, in addition to the standard length, Ringfeder also offers a version with a short spacer. For special customer requirements, customized solutions with a freely determinable spacer length are also possible.

Ring-flex couplings particularly prove their strengths in drives where the positioning accuracy in both directions is of high importance, e.g. in machines with frequent start/stop or reverse operation. Small manufacturing tolerances ensure a high level of true-running accuracy, enabling the use of the couplings even at high speeds and with irregular operating torques.

As usual, Ringfeder attaches great importance to high quality when it comes to the materials chosen. All Ring-flex couplings are made of high-strength steel. The disc pack has been developed with the help of FEM analyses and is made of stainless spring steel. It is connected to the hubs by means of precise sleeves and highly resilient bolts. Per disc pack, a misalignment of up to 1° can be compensated. In addition to the 6-bolt-model, a version with 8 bolts is available for higher torque requirements. Two compact aluminium models are available for low to medium torques.

The couplings have proven successful even under harsh conditions thanks to their high power performance and temperature resistance. With nominal torques of up to 260,000 newton metres and shaft diameters of up to 250 millimetres, Ring-flex multi-disc couplings cover a large range of applications. In addition, they can be used at temperatures of up to 240 degree Celsius, enabling their installation in high-temperature fluid pumps.

When installed horizontally, Ring-flex multiple-disc couplings are also suitable for use in potentially explosive atmospheres. In accordance with EU Directive 94/9/EG (ATEX 95), the couplings in the HS, HD and HC series are complient with and classified as equipment in Group II, Categories 2G/2D. They are approved for use in zones G1, G2, D21 and D22.