Overload clutches, torque limiters, safety couplings

Reliable protection for your machine and machine parts

Collisions in the drive train lead to sudden torque peaks which can damage or even destroy downstream components. In order to prevent this, safety couplings / overload clutches / torque limiters (used synonymously in the following) are installed in the drive train. This guarantees maximum safety and protects against long standstill times.

Operating principle

Overload clutches are mechanical devices which separate the input and output from each other when a specific torque is reached.

For torque transmitters, a principle distinction is made between friction-fit and form-fit torque transmission.

Friction-fit safety couplings are load-holding – the torque transmission is not interrupted in the event of an overload and the load is held with the torque set. Typical representatives of this category are sliding hubs.

Form-fit safety couplings generally perform a mechanical separation of the input and output, and are hence load-separating. Torque transmission is interrupted upon an overload. These couplings are subdivided into ratcheting, synchronous, disengaging, and inhibited couplings according to their engagement and disengagement behaviour. The inhibited coupling is an exception here, as it is load-holding.

As a ratcheting coupling, the overload clutch disengages in the event of an overload, and re-engages in the subsequent depression every 15 °. It is automatically ready for operation again once the overload has been eliminated.

As a synchronous coupling, the overload clutch disengages in the event of an overload and only re-engages again after one revolution (360 °). It is automatically ready for operation again once the overload has been eliminated.

As a disengaging coupling, the overload clutch disengages in the event of an overload and separates the input from the output. It remains disengaged and must be re-engaged manually or via a device during machine standstill.

For the inhibited form-fit torque limiter, the torque transmission is not interrupted and the load is held with the torque set. It serves purely as a torque determiner - in the event of an overload, the drive is shut down via a limit switch.

The benefits

• Friction or positive-fit depending on the application case
• Safety for your drive train
• Protection against long standstill periods