A coupling is an element of a drive line that primarily serves the purpose of transmitting power from one shaft to another, thereby providing for the connection of the driving and driven machine. At the same time, shaft misalignments, e.g. caused by assembly inaccuracies, should be compensated by the coupling while generating minimum reaction forces.
The distinction is made between angular, radial and axial shaft misalignments which may also occur simultaneously. Depending on the coupling type you choose, the dynamic behavior of the entire drive line, and consequently of the machine and its production process, can often be influenced by adjusting the torsional stiffness of the coupling.
The term ATEX is derived from the French denomination "Atmosphères Explosibles" (explosive atmospheres): The ATEX Standard comprises the Equipment Directive 2014/34/EU as well as the Workplace Directive 1999/92/EC. In a previous article about the ATEX Directive we put more emphasis on general issues and theory. In this article we use the example of a flexible claw coupling to explain in more detail how this standard is implemented in practice.
Designers of plants and machines strive for the optimal selection of a coupling for the complete system with many variables requiring consideration. In most cases the main focus is not how maintenance-friendly the product is. Yet – one might say. For a sustainable improvement of the longevity and efficiency of plants, a stronger involvement of maintenance is a must.
Engineers need to consider several aspects for selecting the appropriate coupling such as the type of installation, primary and secondary connection, available space of installation, ease of mounting and dismounting as well as maximum rotational speed and resilience of the coupling. To compensate physical parameters or changes that are not obvious the safety factor, also known as safety multiple or safety coefficient, is taken into account.
Especially in narrow spaces, couplings can only be inspected visually, because the coupling is hardly accessible with conventional measuring devices. Atypical operation noise or vibrations are generally the first signals that there is something wrong with the coupling.
Maintenance and repair: Characteristics of gear couplings, steel disc couplings and (highly) flexible couplings
Couplings are not the most critical part of plants but they have to meet continuously changing requirements. Being reliable, efficient and robust is no longer enough – they should be easy to maintain in order to reduce costs and to avoid downtime. So for choosing the right coupling its characteristics in regard to maintenance and repair are playing a more important role.
Couplings in drive lines are of particular importance because they transmit power between the input and output side, and compensate for inevitably occurring misalignments of the units. Like other machinery elements, couplings need to be serviced at regular intervals. Only if the coupling is optimally tailored to the requirements of the operating conditions and subject to regular maintenance, can it contribute to ensuring the operating reliability and efficiency of a machine or plant.
Every vibratory system consists of an exciter and a mass with a force-transmitting medium in-between. Resonance is caused if this system is periodically excited with its natural frequency. In the field of mechanical engineering, resonance is an undesired phenomenon.