A telescopic handler, or telehandler, is a machine widely used in agriculture and industry. It is similar in appearance and function to a forklift but is more a crane than forklift, with the increased versatility of a single telescopic boom that can extend forwards and upwards from the vehicle. On the end of the boom the operator can fit one of several attachments, such as a bucket, pallet forks, muck grab, or lift table.
The most common attachment for a tele-handler is pallet forks and the most common application is to move loads to and from places unreachable for a conventional forklift. For example, telehandlers have the ability to remove palletized cargo from within a trailer and to place loads on rooftops and other high places. The latter application would otherwise require a crane, which is not always practical or time-efficient.
The advantage of the telehandler is also its biggest limitation: as the boom extends or raises while bearing a load, it acts as a lever and causes the vehicle to become increasingly unstable, despite counterweights in the rear. This means that the lifting capacity quickly decreases as the working radius (distance between the front of the wheels and the centre of the load) increases. A vehicle with a 5,000lb capacity with the boom retracted may be able to safely lift as little as 400lb with it fully extended at a low boom angle. The same machine with a 5,000lb lift capacity with the boom retracted may be able to support as much as 10,000lb with the boom raised to 70°. The operator is equipped with a load chart which helps him determine whether a given task is possible, taking into account weight, boom angle and height. Failing this, most telehandlers utilize a computer which uses sensors to monitor the vehicle, and will warn the operator and/or cut off further control input if the limits of the vehicle are exceeded. Some machines are also equipped with front outriggers and can be called mobile cranes, which extend the lifting capability of the equipment while stationary.
Telehandlers were pioneered by the Matbro company at Horley in Surrey, England who developed them from their articulated cross country forestry forklifts. At first they had a centrally mounted boom on the front section, with the driver's cab on the rear section, as in the Teleram 40, but the rigid chassis design with a rear mounted boom and cab to the side has become more popular.
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