Single operating lever elevating work platform
The Queensland Electrical Safety Office has received advice from an electricity industry contractor that the design and operation of a particular elevating work platform is such that inadvertent movements are possible which could cause an unsafe situation to arise.
The Versalift truck mounted boom lift is able to perform up to three different movements simultaneously. In particular it is possible to retract the boom telescopically while raising the boom arm angle.
This possibility may be exacerbated by the arrangement of the deadman switch which is incorporated into the operating handle. As the 'deadman' button is under the operating handle, pressure to engage this button is in the same direction as that necessary to raise the boom.
If these two functions are engaged while the basket is at normal working height the net direction of movement is upwards. If an operator intended only to retract the boom, and visually checked that this function was occurring, it may not be noticed that the boom arm angle was simultaneously being raised if this function was unintentional.
Such an occurrence may place a person in a dangerous situation.
At this time it is not known whether other machines exhibit similar design or operational characteristics.
It may be appropriate that suitable examination of EWPs is carried out to determine their operational characteristics and that operators are advised of precautions where appropriate.
Last updated October 17, 2005
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