ROBA-topstop brake systems protect gravity-loaded axes

Whether construction machines, rail vehicles or in the energy, automotive or agricultural sectors - Carl Cloos Schweißtechnik GmbH realises production systems for numerous branches. The company's strength lies in particular in its wide-ranging competencies, as at Cloos it is possible to obtain welding technology, robot mechanics and controls as well as positioning, software and sensors all from a single source. This year, the company is to celebrate its 100-year anniversary.

Dipl.-Ing. Dirk Haubrich, Head of Mechanical Design at CLOOS explains: "mayr brakes are used in our large, automated robot welding systems, meaning everywhere where thick steel plates are welded together - for example for construction machines, railways or tractors. Amongst other things, these brakes are installed in our gravity-loaded stroke axes. From a certain size or a certain weight, a redundant system simply is required. The ROBA-topstop brakes act as a second brake in the safety system and ensure that the 2 to 2.5-tonne loads do not drop. They allow us to guarantee the safety of people and machines."

In addition to the stroke axes, which come in both toothed rack and ball screw drive designs, the ROBA-topstop brakes can also be used for eccentrically-loaded axes of rotation. The brakes are generally integrated into the motor adapter of STBER gear units. STBER Antriebstechnik GmbH & Co. KG in Pforzheim is a long-standing cooperation partner of mayr.

mayr supplies STBER with the ROBA-topstop brakes in modified form so that the brake with plug-in coupling replaces the motor adapter otherwise used. STBER has designated this modified product ServoStop. Gear units with integrated ServoStop brakes can be combined with almost all gear units.

Dirk Haubrich emphasises: "As we use the motor gear units in all installation positions, we place particularly high requirements on the tightness of the motor adapter. We have applications on which more than 20 litres of gear oil press down on the motor adapter seal from above. No oil may leak from the gear unit into the brake, as the consequences would be disastrous." For this reason, mayr power transmission supplies specially-adapted and designed safety brakes to STBER Antriebstechnik GmbH & Co. KG.

The valid standards specify a dual brake system design for gravity-loaded axes. Stephan Pittner, Head of Automation at CLOOS explains: "As experts for positioning axes of up to 60 tonnes, we test both systems for function independently of each other in the control system especially developed by CLOOS."

Final inspection: 100 per cent quality controls

As ROBA-topstop brake systems guarantee the safety of people and materials in gravity-loaded axes, they have to work particularly reliably. mayr power transmission has therefore voluntarily subjected the ROBA-topstop safety brakes to a type examination by the Deutsche Gesetzliche Unfallversicherung (German Statutory Accident Insurance; DGUV). This examination confirms that the brake equipment is a "tried and tested component" in terms of Category 1 in accordance with DIN EN ISO 13849-1. Over and above this, the company executes a comprehensive final inspection in addition to numerous quality assurance measures. Every single safety brake which leaves the plant must have passed a 100 per cent inspection after full assembly and adjustment. mayr power transmission has developed a final inspection test stand especially for ROBA-topstop safety brakes. On this stand, function-relevant parameters such as pull-in and drop-out voltage, coil resistance, the dieletric strength of the coil and the proper function of the switching condition monitoring system are determined.

Regarding the testing possibilities, Rudolf Rdel, Design Engineer at mayr power transmission in Mauerstetten explains: "In addition, the brake is tested at high voltages for shorted coils. We also measure the braking torque in clockwise and counter-clockwise direction. The nominal values for this come from the system, meaning that the system knows what the brake should be able to withstand. We have here consistent, standardised measurement conditions. On safety-critical applications, it is important that the braking torque is correct. We would be able to recognise any deviations immediately during the braking torque measurements and are able to make reliable statements. These brakes fulfil their guaranteed characteristics."

All the measurement values determined are archived together with the associated serial number of the brake in an electronic database. This guarantees 100 per cent traceability. The company focuses on clear processes, comprehensive testing possibilities, years of experience and highly-qualified employees so that the brakes by mayr power transmission permanently provide the required standard of safety. Rudolf Rdel adds: "As reliable partners, we have to offer products people can trust in. Safety does not allow for compromises."

Learn more at www.mayr.co.uk.