13.5.7 Operating Access/Clearance

When considering the type of jack to be selected, account must be taken of the access and clearances available to the operative. Jacks which operate from the back allow the jack to be placed further under the load than those with side operation. Jacks with tommy-bar operation may necessitate the operative reaching under the load, a practice which must be avoided, or large clearances to enable the bar to be turned freely. In order to keep operator effort to an acceptable level, the operating levers of ratchet jacks tend to be longer than those of other types of jack, requiring greater clearances to allow full movement. It is a feature of ratchet jacks that in order to allow the holding pawl to engage, the operating lever must make a full stroke, which is not the case with other types of jack.