Torque limiter for standard applications

A torque limiter, also known as a safety clutch, is a mechanical safety device for drive systems. If the transmitted torque exceeds a specified limit, the limiter engages automatically and prevents damage to machinery and components. This helps to prevent component failure, plant downtime, costly repairs and losses in productivity.

If the permissible torque is exceeded, components may break, machinery may fail and unplanned production stoppages may occur. This often leads to high maintenance and repair costs, as well as reduced productivity.

During normal operation, the system operates at a defined torque. If a fault occurs – for example, due to blockages or load peaks – the torque increases. Without protection, the overload is transmitted directly to the components until the weakest element fails. A torque limiter limits or interrupts the power transmission in good time, thereby preventing damage.

Depending on the design, the function can be achieved in different ways:

• Slip principle (slip clutch): The transmitted torque is limited by allowing a controlled amount of slip between the drive and output sides.
• Disengagement (ball or roller limiters): Power transmission is completely interrupted.
• Continuous control (pneumatic limiters): The torque is dynamically adjusted to the prevailing operating conditions.

The use of a torque limiter offers numerous advantages:

• Greater mechanical safety through protection against damage
• Improved system reliability
• Fewer unplanned machine downtimes
• Lower maintenance and repair costs
• Higher productivity and operational continuity
• Increased machine value through improved overall performance

Torque limiters are used wherever mechanical drives need to be protected against overloads.

Typical areas of application include:

• Industrial automation
• Packaging and printing machinery
• Wood and sheet metal working
• Mining and shredding plants
• Conveyor technology
• Pumps, compressors and blowers
• Test benches
• Food and textile industries

The incorporation of a torque limiter is not only good engineering practice, but also complies with the essential safety requirements laid down at European level. The Machinery Directive 2006/42/EG requires manufacturers to carry out a risk assessment and to incorporate protective measures to eliminate or reduce hazards.

In particular, Annex I of the Directive sets out clear principles:

1.1.2. Principles for the integration of safety: The Directive stipulates that ‘risks must be eliminated or reduced as far as possible (integration of safety into the design)’. The torque limiter is a perfect embodiment of this principle.

1.3.2. Risk of failure during operation: ‘Machine parts […] must be able to withstand the stresses to which they are subjected’. A torque limiter ensures that these stresses never exceed the design limits.

1.3.7. Risks from moving parts: ‘All necessary precautions must be taken to prevent the unintended jamming of moving working parts’. The limiter prevents the consequences of such jamming.

Furthermore, the use of reliable components such as torque limiters helps to increase the Performance Level (PL) of a safety function in accordance with the EN ISO 13849-1 standard, thereby reducing the likelihood of dangerous failures and enhancing the machine’s overall safety level.

Yes. In addition to standard solutions, torque limiters can be adapted to specific requirements in terms of torque range, dimensions and installation space. This allows them to be integrated seamlessly into existing systems and ensures a high level of reliability and functionality.