Ski lifts represent one of the most demanding environments for power transmission. Passenger safety relies on a kinematic chain where each component must guarantee absolute reliability under extreme cyclic stresses. Drawing on its long-standing expertise in mechanical engineering, MERGER supports ski resort operators, such as Val Thorens, in ensuring the reliability and maintenance of these strategic equipment systems and provides further insight into the workings of this unique mechanism.
How a ski lift works and the role of the gearbox
The fundamental principle of a ski lift rests on a simple but demanding physical equation. An electric motor, to be efficient and compact, must rotate at a high speed, generally between 1000 and 1500 revolutions per minute. Conversely, to ensure comfortable and safe transport, the cable of a chair lift or cable car must move at a stabilized speed, often between 3 and 6 meters per second. This constraint imposes a rotational speed of the pulley driving force slow, rarely exceeding 20 revolutions per minute.
This is where the speed reducer, the true heart of the driving station. Its role is twofold: it ensures the speed reduction while performing an inverse multiplication of the torque. Without this component, the electric motor would never have the strength rotational torque required to pull the charge of the line when stopped or to compensate for the effect of gravity on vehicles going uphill. In installations such as chairlifts, the reducer is the guarantor of this quiet strength which allows us to maintain a cadence constant regardless of seat occupancy.
Typology and location of transmission components
The architecture of a drive station is structured around two main axes: the high-speed shaft and the low-speed shaft. reducer is invariably located between these two segments. The service brake is generally found on the high-speed shaft, at the motor output. The service brake is fixed on the low-speed shaft, at the gearbox output. drive pulley, often equipped with its own safety brakes known as "pulley brakes".
Several noise reduction technologies exist, adapted to the specific characteristics of the devices. parallel shaft reducers Orthogonal or orthogonal shafts are classic mechanical shafts, valued for their robustness and ease of maintenance on medium-power equipment. However, for high-stress installations such as cable cars, the following are preferred: epicycloidal reducers (or planetary gear trains). This technology allows the transmission of couples massive components are achieved within a limited volume thanks to a load distribution across several satellites rotating around a central pinion. This compactness is an asset for integration into modern drive stations where space is limited.
Emergency motor: the Merger mechanical gearbox allows coupling to the reduction gear
The regulation of transportation Cabled operation imposes absolute safety, meaning that the installation must be able to be evacuated even in the event of a total failure of the main system (power outage or motor failure). To meet this requirement, each device is equipped with a backup enginesometimes a combustion engine or sometimes a hydraulic one.
gearboxes ou transfer boxes MERGER intervene precisely in this redundancy scheme. Unlike the main reducer, which operates continuously, the first aid kit is an organ of couplingIt allows you to engage the auxiliary engine on the kinematic chain. In some cases, this box This allows bypassing the main gearbox if it fails, by acting directly on a toothed ring attached to the pulley. This equipment is critical: it must be able to remain stationary for months, then... function instantly under maximum load to bring users back to the station.
Maintenance and vigilance: the life of the mechanism in an extreme environment
The longevity of a legacy design At high altitudes, this depends not only on its initial robustness, but also on the rigor of the technical monitoring. interventions de MERGER in high-altitude resorts such as Val Thorens They highlight specific areas of concern. The primary enemy of the transmission is condensation. Temperature fluctuations between day and night cause water to form inside the casings, which degrades the properties of the oil and can lead to bearing corrosion.
A maintenance Precision rests on several pillars. MERGER carries out on-site inspections in this context.
The vibration analysis is the most revealing: it allows you to listen to the "signature" of the gears and bearings. A change in this signature often indicates a phenomenon of pitting (micro-tearing of material on the teeth) or the beginning of bearing fatigue.
Le control of backlash, or play between teeth, is also crucial to avoid shocks during reversing or sudden stops.
Finally MERGER provides a solution to obsolescence: through the reverse engineeringIt is possible to remanufacture identical gears or shafts for equipment whose original manufacturers have disappeared, thus extending the lifespan of the installations while guaranteeing their compliance with current safety standards. The company still has the cried original who made the moving for Strasbourg up to today's workshop at Corbas.
For a manager of lifts mechanicalPower transmission is a major economic and safety issue. A failure of the main gearbox results in a complete shutdown of the equipment, directly impacting commercial operations. The need for reliability leads to a preference for robust equipment capable of withstanding continuous operation throughout the winter season.
Sources: remontes-mecaniques.net