A level-luffing crane is a crane mechanism where the hook remains at the same level whilst luffing; moving the jib up and down, so as to move the hook inwards and outwards relative to the base. Usually the description is only applied to those with a luffing jib that have some additional mechanism applied to keep the hook level when luffing.
Level-luffing is most important when careful movement of a load near ground level is required, such as in construction or shipbuilding. This partially explains the popularity of fixed horizontal jibs in these fields.
Level-luffing is most important when careful movement of a load near ground level is required, such as in construction or shipbuilding. This partially explains the popularity of fixed horizontal jibs in these fields.
Types Level Luffing Crane
Toplis cable luffing
The crane's hook is kept level by automatically paying out enough extra cable to compensate for this.
Powered level-luffing
The first of these systems used mechanical clutches between luffing and hoist drums, giving simplicity and a "near level" result.
Horse-head jibs
By careful design of the geometry, this keeps level merely by the linked action of the pivots.
Luffing cabs
Used for tasks such as ship unloading, the view from driver's cab is greatly improved by cantilevering it forwards and over the ship.
