The individually equipped car, one's own home or, most appropriate in the literal sense to this article's heading, the tailor made suit: all things that are designed according to one's own, quite special ideas. What does this have to do with coupling technology A whole bundle. Indeed, the solutions and processes in industry are becoming more and more individual – driven by the increasingly varied requirements of users. The coupling manufacturers react and provide an active impetus with their own innovations.

"Industrial production is characterised by a high level of customisation of the products under the conditions of highly flexibilised (large series) production", according to the declaration of the Federal Ministry for Research and Education on the subject of "Industry 4.0". Individualisation and flexibility need freedom. Coupling technology is very closely intermeshed with the numerous industries for which it delivers solutions and opens up perspectives for future development. For the R+W Antriebselemente GmbH this means: One is pleased that one has access to the numerous technological possibilities that the company has acquired over the past decades, and at the same time is aware of the growing challenges as well as the rising expense that these requirements mean. Thus the standard product range is constantly expanding and more and more special solutions are being developed.

Efficiency stands in the foreground
The starting point is the request from the design engineers: One considers the overall context at first in order to understand what the user requires. What is the requirement How can the couplings meet this Coupling manufacturers must find and work out solutions for the existing demand. Wealth of ideas, seeing the big picture and practical experience play and important role here. Over the years, R+W has developed a wide range of standard solutions for precision and industrial drive couplings, enabling it to cover different applications directly.

R+W offers various solutions in the area of precision safety couplings, e.g. the proven SK series (Fig 1), suitable for torques between 0.1 and 2,800 Nm. It is available for direct and indirect mounting by clamping hub, conical clamping ring or keyway mounting and in a torsionally stiff metal bellows version as well as in a vibration-damping elastomer version (ES). The different models are available in each case with different operating principles: single-position, multi-position, load locking and with full disengagement.

To do justice to the constantly changing requirements of the market, for example for lower mass moment of inertia, higher operating speeds or more efficient processes, R+W already developed in 2010 lightweight safety couplings of the SL TORQLIGHT® series (Fig. 2) and thus set standards on the market. TORQLIGHT® has higher power density, lower weight and costs less than the models of the standard series. R+W achieves this by intelligent lightweight design in combination with high-tech materials using the latest manufacturing techniques. Such examples show how further or completely new developments are constantly being added to the product range – responding to the needs of users with a view to functions, equipment and material used in production.

Solutions for production and automation
Apart from the actual production processes, material flow and handling also profit from suitable coupling solutions. Torsionally stiff or vibration-damping zero backlash servo couplings are predestined for use in automation, since they fulfil the main requirements on highly dynamic servo-axes. Over the years, solutions from R+W have proven themselves a thousand times over in this area. The role in automation of metal bellows (Fig. 3), elastomer (Fig. 4) and safety couplings as well as universal shafts (Fig. 5) for safe and in the final analysis efficient processes is small in a physical sense, but significant as far as functions are concerned.

Applications that R+W cannot cover directly with a standard product require a special solution. The motto in the development department here is: as efficient as possible and as individual as necessary, to keep the investment and life cycle costs within bounds for the customer. For example, in a comparatively short development time of a few weeks, the company developed a metal bellows coupling of press fit design for the largest machine in the world, the CERN research project, and a safety coupling for the ISS space station. A metal bellows coupling suitable for peak torques of up to 850,000 Nm was developed for wind turbines (Fig. 6) – clearly more than is possible with standard products.

Mechanical safety couplings fit for the future
These practical examples demonstrate the relevance of coupling technology for numerous applications in different industries. To prevent damage to machinery, one also uses electrical versions, for example in machine and plant construction, apart from these mechanically functioning elements – from current-dependent overload protection through voltage and power monitoring components up to torque control devices. If one considers the two operating principles in detail, it becomes clear that mechanical elements have clear advantages compared with electronic control systems.

This is particularly evident in the response time of both versions: Here mechanical safety couplings are a few milliseconds faster and thus clearly better. Finally, speed is the decisive factor in safety systems. The faster the control shuts off, or the component interrupts torque transmission, the less consequential is the damage to the components or even to the entire machine. When it comes to protecting investments and avoiding downtimes, fractions of a second are decisive. Mechanical safety couplings give users a valuable advantage.

A further advantage of the mechanical alternative is the number of possible sources of error. In order to equip plants with electronic controls, a multitude of sensors is necessary to ensure optimal protection. In addition to the sensors, torque measuring instruments are fitted at important places within the system. This arrangement of several safety devices accounts for sources of error. The system must be maintained on a regular basis. In addition, sensors offer no absolute guarantee of safety, for correct operation cannot be guaranteed due to dirt, deflection of infra-red rays or masking of the sensors, for example.

Mechanical safety couplings also win due to their ease of use and easy adjustment. If, for example, the mass moments of inertia in the entire drive line are too high, so that the safety coupling would respond regularly when decelerating and accelerating the drive line, then the disengagement torque can be adapted to the circumstances without difficulty, thanks to the large adjustment range. Thanks to the variable installation possibilities, design engineers can use the coupling exactly at the place in the drive line where the probability of an overload is the greatest.

Safety through Quality
Against the background of the subject of "safety", the requirements on quality are correspondingly high. R+W responds to this challenge by employing in-house test stands (Fig. 7) - so that there is speedy feedback between quality assurance and development. On this basis, quality and functionality can be assessed, documented, and, if necessary, improved on. The test stands offer testing capacities for different applications to obtain the wanted data as quickly as possible. R+W operates a total of four types of test stands: a vibration test stand, one for universal shafts, one for special applications and a heavy duty test stand. The test stands deliver reliable results in the shortest time under the company's own roof.

The couplings are designed in a dialogue with customers according to their specific requirements. In close contact with the engineers of the user companies, R+W develops its products continuously, in order to offer specific solutions to meet the requirements in each case. The company's own R&D department and prototyping and co-operation with universities and colleges of applied science also make their contribution. It is a question of solutions that provide a secure investment in the efficiency and reliability of equipment. Technological competence in the field of couplings and consideration of the customer's application form the basis for the correct and best solution.

Freedom for Innovations
In the so called "Internet of Things" objects like machines and robots exchange information among one another and make it available to mankind. Numerous new opportunities are opened up with a view to further developments and innovations. With regard to the demand for increasingly strong individualisation of products and flexibility of production capacities, networked and highly automated production assures companies competitiveness in high-wage environments. Whether standard or special solutions, couplings play an important role today, and in the future, for flexible, efficient, and intelligent processes.

Author: Frank Kronmüller
Prokurist Executive Vice President


R+W America

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Bensenville, IL 60106


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