Design The Safety Couplings Correctly

2023 Author: Hannah Pearcy | [email protected]. Last modified: 2023-05-24 11:12

If errors occur during the operation of a machine or system, very high torques can occur in the drive train, which can damage various drive components. In the worst case, the machine stops afterwards. Safety clutches can prevent this scenario. Because when a defined torque value is exceeded, they separate the input and output of a drive train - in just a few milliseconds. This disengagement can minimize damage and at best even prevent it.

Coupling with safe overload function

The requirements for safety couplings are therefore extremely high. Reliability comes first. "A safe overload function with a high repeatability of the release torque, even at high speeds and in both directions of rotation, is required," says Roland Arnold, design manager at Jakob Antriebstechnik. The release torque is the defined value at which the clutch triggers the uncoupling. It is therefore important "The most important criterion is that safety clutches must trigger safely and reliably. Otherwise, a safety clutch makes no sense," confirms Ralf Epple, product manager at von Mayr power transmission. Sven Karpstein, Managing Director of KBK Antriebstechnik, adds:“The trigger torque required must be estimated as precisely as possible from the outset. All of our overload clutches can be infinitely adjusted, but first you have to choose an overload range that the customer can no longer modify.”

Picture gallery

Safety clutches are used in a wide variety of industries. But especially when machine downtimes have drastic consequences and cause high costs. “Our safety couplings are traditionally used in highly productive machines such as machine tools or packaging machines. In addition, automation has also found its way into many other areas, which makes overload protection necessary to protect people and machines, especially in the case of expensive or safety-related processes,”explains Sven Karpstein.

Who or what should be protected?

Securing people and machines is an important point. Because who or what you want to protect plays an important role. Not all safety couplings are suitable for use in personal safety. When selecting a coupling, care should be taken or this should be clarified with the manufacturers. Most manufacturers have a wide standard portfolio of safety couplings. Some use modular systems to make this more flexible and adaptable to special applications. If the standard offer is not sufficient, many providers are open to customer-specific adaptations and new developments.

Safety clutch

Mechanical engineering student develops new safety clutch

The trend towards ever more efficient processes also requires solutions that are as light and compact as possible. R + W Antriebstechnik has taken up these requirements, for example, in its SL series. According to the manufacturer, this coupling combines higher power densities, lower weight and lower costs compared to the classic standard series. The model series is made from high-tech materials and combined with new surface coatings. The special materials ensure that the weight of the coupling is reduced. In conjunction with special disc springs and an optimized ball detent mechanism, the couplings should enable a torque increase of up to 50% while reducing the weight by 60% compared to the standard coupling.

Additional information on the checklist: Your way to the right safety coupling

With the range of safety clutches, it is important to be structured when choosing. The experts from Mayr power transmission have drawn up a checklist that designers can use as a guide:

• Define coupling requirements as precisely as possible based on the technical data of the drive and the drive constellation.
• Keep an eye on important parameters such as torque, speed, transmission behavior in the event of an overload and clutch design (friction clutch, locking body clutch, permanent slip clutch).
• With positive-locking couplings, ensure that the torque is transmitted without play. Clutches with play tend to wear, particularly in reverse operation and alternating torques, and thus to early failure.
• Pay attention to ease of assembly, operation and adjustment. Easy handling avoids application errors and increases functional and operational safety.
• Get advice from manufacturers with development, manufacturing and application experience as well as a wide range of products. Worldwide on-site service from suppliers can also be an advantage.

New coupling series and sizes

Sven Karpstein, on the other hand, refers to the half-shell construction that was developed at KBK Antriebstechnik. It is intended to enable radial installation of the overload clutches with metal bellows or elastomer, thus making assembly easier and increasing operational safety. The company also continues to expand the miniature sizes.

Mayr power transmission also has new sizes to offer. For the EAS-HSE high-speed clutches with speeds up to 25,000 min ^-1. The company also has safety clutches in its range that automatically engage again by slowly turning backwards, without the use of pneumatics or hydraulics.

Jakob Antriebstechnik also has a clutch that engages automatically. The re-engagement takes place automatically when the direction of rotation is reversed at low speed. Downtimes should be reduced effectively.

Enabler of construction

These technologies have game-changing potential

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