Derrick ballast for the LR 1400.1 SX debuts at Conexpo with VarioTray and position monitoring
Liebherr showed the LR 1400.1 SX crawler crane with derrick equipment and suspended counterweight for the first time at Conexpo. The addition targets heavy lifts on long boom and luffing jib combinations, with VarioTray handling the fine adjustment.
What the derrick adds
The design brief for the derrick equipment was to widen the LR 1400.1 SX’s range of applications rather than simply raise a headline figure. The gain shows up where it usually does: on heavy lifts with the crawler crane configured with long main booms and luffing jibs, where the derrick ballast lifts the available capacities and opens up boom combinations that would otherwise be out of reach.
The suspended counterweight is made up of a main and an additional counterweight and is adjusted by an infinitely variable hydraulic extension device. With VarioTray, the additional counterweight can be increased or reduced in slabs of 22,250 lb each without an auxiliary crane – a practical point on sites where bringing in a second machine is the expensive part of the job.
Position monitoring of the suspended counterweight is part of the package. If the ballast is set down on the ground, the crane cannot slew, travel or move the counterweight until it is picked up again.
Assistance systems on the machine
Liebherr has grouped several operator aids around the crane’s safety concept. A gradient travel aid supports work on slopes: the control system calculates the centre of gravity automatically and warns before the crane leaves the safe envelope. While travelling, the operator is shown the permissible and actual gradient together with the overall centre of gravity, and the boom angle can be adjusted to bring the machine back inside limits.
Ground pressure visualisation calculates the current ground pressure in real time and compares it against limits defined for the site, with the result displayed in the cab so the operator can see when the machine is approaching a critical area. Ground pressure reduction plates can be lowered during lifting work to enlarge the contact area, cutting ground pressure by more than half – useful in particular when lifting long booms off the ground.
The boom up-and-down assistant covers erecting and lowering. It flags the approach to the tipping border and stops the movement before the operator enters an unsafe zone. Controlled folding of the jib starts at the press of a button and the speed of laying down is governed with a single joystick, with the system selecting the safest sequence rather than leaving the operator to work the main boom and jib winches separately.
Planning the configuration
As a multipurpose machine the LR 1400.1 SX turns up on bridge and tunnel work, stadium and factory construction with steel or precast elements, energy sector projects, lifting on tall buildings and barge applications. Liebherr’s Crane Planner 2.0 software is used to settle on the boom combination for a given jobsite and to simulate the lift beforehand.
Source: Liebherr — Photos: Liebherr