Load weighing devices play a vital role in the safety and traffic management of lift installations. The initial set up, on-going maintenance and adjustment is important for many reasons.
The primary function is to ensure that an overloaded lift is prevented from travelling. In most instances audible and visual indication highlights that the safe working load has been exceeded. This means that until the load has been reduced the lift will not move from floor level. A poorly adjusted device may result in the lift moving with excess weight.
EN 81 states that if a load of 125% engages the safety gear it may be necessary to remove some or all of the load before the safety gear may be reset. If the load weighing device was out of calibration and the lift was allowed to move it could be a major problem if the lift is stuck between floors with passengers in the lift car.
Load weighing devices are used to detect car loads and will bypass active landing calls to avoid unnecessary stops where passengers will not be able to enter the lift. In addition load weighing devices will activate up peak control algorithms to enable traffic performance to be realised.
All too often we discover during audits of site investigations that load weighing devices are not calibrated and do not provide the safety back up or allow the lifts to perform to provide good passenger service.
