Safe and reliable couplings and brakes for ropeway systems – precise, durable, low-maintenance

Ropeway systems combine sophisticated mechanics with a special responsibility: they transport people safely, reliably and often for many hours at a time. Gondolas, cabins, chairlifts and maintenance equipment must be accelerated, braked and held in defined positions in a controlled manner.

However, a ropeway system does not always operate under consistent conditions. Outside temperatures, snow, ice, moisture, wind and fluctuating passenger numbers all affect its operation.

Added to this are high load cycles, frequent switching operations and the need to ensure a safe state even in the event of faults.

For couplings and brakes, this means they must do more than just perform well. They must function predictably, achieve a long service life and integrate reliably into the safety architecture of the entire system. When it comes to safety-critical movements, every function – and every defined state – counts.

Smooth engagement, secure hold

Mönninghoff develops clutch and brake systems that are tailored to the torque, speed, load profile, switching frequency, safety functions and installation space of the respective cable car system.

Electromagnetic multi-disc clutches

Electromagnetic multi-disc clutches are suitable for the smooth engagement and disengagement of drives under high loads. They combine high repeatability with a compact design and are a viable option when a drive needs to be engaged or disengaged regularly.

Possible applications include

• engaging and disengaging main or auxiliary drives
• engaging maintenance and service drives
• connecting the motor, gearbox and output shaft
• frequent engagement and disengagement under varying operating conditions
• Applications with high requirements for low heat generation

A suitably designed multi-disc clutch can help to transmit loads in a controlled manner and relieve the mechanical components of the system. It is important to match the clutch to the torque, speed, engagement time and thermal load.

Electromagnetic toothed clutches

Electromagnetic toothed clutches enable defined, positive-engagement switching operations. They can be used where drive stages need to be precisely connected or disconnected and movements need to be transmitted with as little play as possible.

Typical applications include

• the engagement and disengagement of travel or lifting drives
• defined switching operations in maintenance and positioning systems

In cableway systems, brakes do more than simply slow down movement. They can hold shafts, drums, lifting mechanisms or other assemblies in a defined position and, where necessary, assist in bringing the system to a safe standstill.

When selecting and designing brakes, the following tasks, amongst others, may be taken into account

• Holding drive and working shafts
• Securing gondolas, cabins or chair positions
• Deceleration of moving masses
• Emergency stops and controlled shutdowns
• Holding lifting, tensioning and locking devices
• Securing during maintenance and inspection
• Support for redundant braking and safety concepts

The suitability of a braking solution depends on the specific system and the intended safety function. Key factors include braking torque, holding torque, rotational speed, braking distance, switching time

Safety is a systemic issue

In a ropeway system, the clutch or brake must not be considered in isolation. What is crucial is the interaction with the motor, gearbox, rope, shafts, bearings, control system, sensors and the mechanical safety functions.

The following parameters, amongst others, may be taken into account for the design

• Torque and speed
• Acceleration and deceleration behaviour
• Mass and inertia of the moving assemblies
• Weight of gondola, cabin or chair
• Possible passenger and load ranges
• Cable length, drive concept and operating mode
• Switching frequency and daily operating time
• Number of expected operating cycles
• Desired stopping and braking positions
• Behaviour in the event of a power failure and emergency stop
• Wind, snow, ice, humidity and temperature
• Vibrations, impacts and potential oscillations
• Available installation space and connection geometry
• Requirements for monitoring, diagnostics and documentation

Mönninghoff develops bespoke solutions that can be tailored to these parameters and integrated into the overall system. The focus is not on the individual component, but on the safe and reliable operation of the entire system.

Defined states for critical situations

Safety-critical applications require a detailed analysis of potential fault scenarios. What happens in the event of a power cut? How is a moving assembly brought to a safe stop? How is a position maintained when the drive is at a standstill? How can a maintenance state be safely established?

A suitable clutch and brake solution can help to establish clear operating states. Depending on the application, the following points may be relevant

• mechanical holding independent of the running drive
• safe disengagement or limitation of the force flow
• controlled deceleration in the event of faults
• defined positioning of assemblies
• Monitoring of switching and holding states
• Integration into redundant safety concepts
• Safe reset and restart
• Plannable testing and maintenance

The specific safety function must always be assessed and validated in conjunction with the overall system concept. This applies particularly to cable cars: trust travels with you – technical verification ensures that it is in the right place.

From development to a tested production solution

Components can be tailored to their intended function as early as the development and prototyping phase. Particularly in dynamic and safety-critical applications, it makes sense to test switching behaviour, load-bearing capacity and holding function at an early stage.

Possible test criteria include

• Holding torque and holding accuracy
• Braking torque and braking distance
• Switching time and switching reliability
• Behaviour under varying loads and speeds
• Function during emergency stops and power failures
• Behaviour in cold, damp conditions and other environmental influences
• Behaviour under vibrations and dynamic shocks
• Continuous operation and wear
• Thermal stress
• Integration into mechanical, control and sensor systems
• Performance of individual components and the overall system

The results can be used to optimise the solution in a targeted manner and tailor it to the specific cable car design. In this way, a technical requirement is transformed into a robust production-ready solution.