Mayr Antriebstechnik takes into account fundamental and proven safety principles in the development and production of "Roba-stop brakes" long before they have been defined in the EN ISO 13849-2 standard. All components are safely dimensioned and manufactured exclusively from high-quality, well-known and proven materials.
The standard EN ISO 13849-1 requires that safety concepts be implemented in machines. This obliges plant and machine manufacturers to check their products for compliance with the new standard and, if necessary, to adapt them to avoid endangering people. Dangers arise, for example, when vertical axes fall unintentionally.
Basically, there are several ways to achieve the required performance level for such axes. An extremely effective variant is an additional, redundant safety brake. But not every brake is suitable for it. It must have the following characteristics to meet the requirements of the new standard:
The basic requirement is that it works according to the fail-safe principle, ie it is closed in the de-energized state. But that alone says little about the quality and reliability of a brake. Roba-stop brakes, for example, have been tested using the helical compression springs used to generate the braking force of stainless steel and the durability of 10 millions of load cycles.
The use of proven springs made of known materials pays off. In 40 years of field experience, the springs have proven that they will not break. Additional security results from the application of the proven safety principle "multiplication of parts". In general, more than 5 springs work in a brake. This reduces the error effect. In addition, Mayr has long-established design principles that have now been defined in the standard, and uses in its brakes sufficiently guided springs with a wire diameter greater than the distance between two turns. Should a spring break, the two fragments can not screw together. The original spring length and the spring force are largely retained. What applies to the springs, of course, applies to all other components, namely the consistent consideration of proven safety principles.
The safe function of the brake also requires safe control. Pinch contactors, welded contacts or other faults must not impair safety. With redundant, series-connected control elements in conjunction with fault detection and fault feedback, safe controls can be established. This ensures that the brake is always safely de-energized, for example, in the event of an emergency stop and brakes reliably.