Lift brakes: safety knows no compromises

Safety-relevant components such as lift brakes have to meet the highest quality requirements. Nevertheless, due to intense global competition in the lift sector, price repeatedly plays a decisive role even when it comes to safety-relevant components.

But a well-founded selection for reliable products still has to be made since there can be no compromises when it comes to safety.

By Alexander Hutler

Selecting the right products is becoming increasingly difficult when it comes to lift brakes. Up to about ten years ago, there were only a few brake manufacturers in the market, for the most part SME companies with extensive experience. Their expertise guaranteed quality and reliability. However, the globalisation of the market for lift drives, the enormous competitive intensity and associated problems with copies has also resulted in huge competitive pressure in recent years when it comes to safety-critical components such as lift brakes.

While in the past a clear commitment to reliability and top quality represented the consensus in the sector, market participants today repeatedly mention price as the most important decision criterion in discussions. But the rapid developments here represent a great potential risk. Young, newly established market participants are now offering products on the world market at low prices, putting them at an advantage in such negotiations.

But this is counterbalanced by the lack of experience of these providers. They rely to a great extent on the latest gearless technology but many of them have little experience with it. But budget brakes that have to cut corners in regard to the materials used and safety involve an incalculable risk.

Specify and test brakes

The cooperation with large, globally operating lift manufacturers continues to show that these companies are relying to an increased extent on quality components and adhere strictly to the European lift standard EN 81 – even where it is not mandatory. In addition, the leading manufacturers are going to considerable lengths to specify safety-relevant parts precisely and verify them in extensive test procedures.

Moreover, due to daily field experience, these companies have corresponding input from the market. This makes it straightforward for them to continually specify their products or product requirements in greater detail and include critical points in the qualification process.

No feedback from field data

Photo: © mayr Antriebstechnik

However, this cannot be applied in full to the subcontractor industry. For example, smaller lift companies and motor manufacturers get no corresponding feedback from field data. They do not have the resources to employ a large engineering team and usually work with simpler methods to specify and test brakes. They do not have the bandwidth either and often only supply regional areas of deployment in which particular problems may not occur very often.

As a result, if such a drive manufacturer needs reliable brakes, it will orient itself according to points with which it is already familiar. But what criteria can a manufacturer of lift motors – especially in gearless technology – apply to find a reliable brake?

Certified quality process

As in the purchasing area in general, the potential supplier should first undergo close examination here. A company does not qualify itself simply by the fact that it can produce brakes. Corresponding manufacturing competence and a certified quality process are indispensable preconditions, just like well-founded experience with brakes for lift drives.

In addition, the company must have had a large number of lift brakes on the market for many years. This is the only way it can know the risks and supply reliable products. This is because prototype tests in which lifts have their functionality tested once do not say anything about the quality of the brakes in large unit numbers.

Every single brake has to be supplied in the quality required. This requires a corresponding test routine. The reason for this is that manufacturers with little experience do not know what gaps exist in their knowledge. To guarantee the safety needed on a permanent basis, clear processes, comprehensive test options, many years of experience and highly qualified employees are indispensable. This costs money but only in this way is safety guaranteed.

100 percent traceability

Consequently, all mayr safety brakes are subject to meticulous quality control. These include quality assurance measures during the construction process and a comprehensive final test. Before delivery, all brakes undergo exhaustive testing on test rigs and the functionally relevant values are documented.

An electronic database in which the measurement values are archived with the associated serial numbers of a product guarantees 100 percent traceability. The same quality standards as in Germany also apply to other production plants in China and Poland. For example, the operational quality management system in Zhangjiagang is certified according to ISO 9001 as in Mauerstetten.

Painstaking service life design

When selecting a brake supplier, the product specification and its comparison with the criteria required are also very important. Special attention must be paid here to consideration of the lift brakes under critical conditions as well, such as high outdoor temperatures or high humidity, which can also occur in actual deployment.

Care should also be taken that specified values are not just achieved in new condition. Behaviour should instead be considered across the entire service life. The many years of experience and countless experiments of our development and testing department form the basis for conscientious service life design, taking realistic and verified brake torque tolerances into account. All brake components have safe dimensions and are only made from high quality, known and proven materials. The brakes are designed to reliably achieve the rated torque required under all operational conditions that occur irrespective e.g. of the ambient temperature or humidity.

For smaller manufacturers, prescribing corresponding brakes from established manufacturers in their specifications makes sense as well as making sure that these are also used. Checking type plates is a potential measure for ensuring this. This guarantees that these components provide the reliability required since when it comes to safety there can be no compromises.

The author is key account manager in the lift brake task force at Mayr Antriebstechnik, a safety brake manufacturer based in Germany.

More information: mayr.de