The company mayr® power transmission, the leading supplier of application-specific safety brakes, is presenting its unsurpassed wide range of electromagnetic, pneumatic and hydraulic vertical axis brakes at this year's EMO in Hall 7 / Booth D30. These systems safeguard against all hazardous situations that can occur during the operation of gravity-loaded axes. Furthermore, the company provides a checklist to support the validation of the safety brakes.
Gravity-loaded axes in machine tools must be safe. Ensuring this is the responsibility of the design engeineer. Based on the risk assessment, a safety function must be defined and each component in the chain must be validated. To consolidate the flood of information and thus make the work of design engineers easier, mayr® power transmission provides a smart validation aid for its safety brakes. A well-structured checklist based on DIN EN ISO 13849-2 can be used to easily and reliably check the correct selection of brakes. Following the risk assessment and validation of the individual components, any hazards that might arise must be identified and reduced to a minimum.
Reliable brakes for vertical axes
Safety brakes according to the fail-safe principle are the first choice for applications with vertical axes, as these brakes generate the braking force through thrust springs, are closed in de-energized condition and thus fulfil the basic safety principle of energy separation. Reliable motor drives are also able to decelerate vertically-moved loads to a standstill even in case of power supply failure (SS1 operation), however, they cannot subsequently hold loads suspended without a supply of power. Depending on the design, there are different possibilities for integrating or retrofitting safety brakes.
“The safety brakes of the ROBA®-topstop®, ROBA®-guidestop and ROBA®-linearstop series meet the requirements for a safe holding or braking system,” explains Bernd Kees, Product Manager at mayr® power transmission, describing the function: “All our series operate according to the fail-safe principle. Depending on the series, the brakes are released either electromagnetically, pneumatically or hydraulically.” These brakes are used both as single brakes or in combination with a second brake as two-channel or redundant systems providing protection against high hazards.
ROBA®-topstop® – Independent module between motor and spindle
With the ROBA®-topstop® brake system, mayr® power transmission has an independent module in its product range which holds the vertical axis safely in any position – even if the motor is disassembled for maintenance or transport. The axis does not have to be additionally supported, which considerably accelerates the replacement of the drive motor, for example. This reduces costs, and also downtimes for repairs are considerably shorter. Thanks to its adapted flange dimensions, the brake can also be easily integrated into existing constructions. The safety brake meets high IP standards and is currently available up to Protection IP66.
Wide range of linear brakes
Two additional proven safety braking systems that are frequently used to safeguard linear movements are brakes that act either on separate round rods or on guide rails. These include, for example, the ROBA®-linearstop brakes (piston rod) and the ROBA®-guidestop brakes (guide rail) by mayr® power transmission. These linear brakes are particularly suitable for use in gravity loaded axes, as they are mounted directly on the masses which are to be braked or held. Drive elements such as toothed belts, couplings or spindle nuts, which are included in the power flow in other braking systems and could have an influence on safety, can be disregarded. If linear brakes are also used as a second brake unit, for example in addition to a motor brake, their operating principle – on a rod or rail – also ensures diversitary redundancy with an increased Common Cause Failure value (CCF value). Linear brakes can be used in many different application fields. That is the reason why mayr® power transmission offers a wide range of linear brakes in pneumatic, hydraulic and electromagnetic designs. “We are the only manufacturer to offer electrically opening linear brakes which are also safety brakes,” Bernd Kees explains. “Users looking for solutions can turn to us for systems with both round rods and guide rails.”
mayr® power transmission at the EMO 2023: Hall 7, Booth D30