Even the heavy machinery is more compact, the drives are increasingly more difficult to achieve. Because a reliable overload protection is also necessary here, has Mayr Antriebstechnik with the "EAS reverse"A new free-type safety coupling developed: When you all functional processes on the drive can be automated, it is easy to handle, allowing long down times and snapped by slowly rotating backwards again automatically. A housing protects against dust and splash water.
Where stones break, hot steel steams or machines eat through rock, only robust and solidly dimensioned safety couplings withstand the extreme loads. Because the often harsh operating and environmental conditions in heavy machinery such as dust, spray, heat or cold not only burden the workers at the plants, but also the individual components of the powertrain.
Precisely because of these harsh environmental conditions, the drive trains are often encapsulated in these machines and thus difficult to access. The drive specialist has therefore developed a robust safety coupling with EAS-reverse, which withstands both high loads and automatically re-engages - suitable for drives without access to re-engagement. It protects the large machines permanently and reliably from damage caused by overload, thus ensuring operational safety and the highest productivity of large systems.
Patented functional principle"With the new safety coupling EAS-reverse, all functional sequences can be automated via the drive," explains Norbert Vogl, developer at Mayr. "It is a disconnecting clutch, which automatically engages again only by slow reverse rotation, without the use of pneumatics or hydraulics."
The torque transmission elements used in EAS reverse are double cylindrical rollers. These ensure extremely robust torque transmission and favorable contact conditions. Thus, the double rollers are characterized by high Wälzanteile when disengaging and thus by low friction components. "Due to the low friction components, the clutch has a favorable service factor," explains Norbert Vogl. "This service factor is also positively influenced by the fact that the EAS-reverse works with a direct high-stiffness torque transmission mechanism that does not require an additional release mechanism." The torque transmission is extremely low in play (<0,05 °). All functional parts of the coupling are hardened.
Immediate drop in torqueIn case of overload, when the torque exceeds the value set on the clutch, the EAS reverse input and output disconnects in fractions of a second almost free of residual torque with high switch-off and repeat accuracy. The kinetic energy of the rotating masses stored in the system can run out freely. The use of disc springs with a negative characteristic results in an immediate drop in torque. A so-called pumping or breathing of the clutch is thus excluded. The wear of the Ausrastmechanismus is thus low. This safety coupling can cope with long run-out times of the drive after the response.
For the definition of the permissible flow time, only the robust double bearing of the coupling should be considered. Although the drive must be switched off promptly after disengaging the clutch, targeted braking of the engine is not required. The overload signal provides, for example, a non-contact limit switch, which permanently monitors the operating state of the clutch. Due to the complete separation of drive and output no detent impacts occur during the follow-up time, which could have a negative effect on the drive train. The clutch is engaged again by reversing the direction of rotation at a speed <10 min-1.
Easy to handle and flexible to useThe new EAS-reverse is easy to handle and with its numerous variants and additional features stands for adapted, industry-optimized solutions. For example, the combination with an elastomer coupling allows easy separation of the drive train by loosening a few screws, without having to move the engine or transmission. In addition, the combination with a brake disc on the output side can be implemented for applications with load-sustaining output.
The coupling can also be easily integrated into a solid housing with standard IEC or Nema dimensions. It is thus dust and splash-proof, adverse environmental conditions can not affect the clutch. By default, the EAS-reverse can withstand a temperature range from -20 ° to + 40 ° C, and extensions to temperatures from -30 ° to + 80 ° C are also possible.
Since the safety coupling with the first three sizes has hitherto covered a torque range from 80 to 2500 Nm, the extension now includes a fourth size up to 5000 Nm and a bore diameter up to 100 mm. Before a clutch leaves the plant of the drive specialist in Mauerstetten, it is thoroughly tested and set exactly to the required value. For this purpose, the company has a variety of modern testing options and can draw on decades of experience. An electronic database, in which the measured values are archived together with the associated serial numbers of a product, guarantees an 100-percent traceability.