Big cranes quickly lift materials up to the top storey of a building under construction. But even the best operator can struggle to place a load with great accuracy, especially when the load is heavy. Employing two cranes to tandem lift the load doubles the cost and increases the risk.
Enerpac’s SyncHoist system enables a single crane to place a load much more precisely than the crane would be able to. The system consists of four bi-directional hydraulic cylinders with stroke sensors connected to ropes that hang from a crane hook. Once the load is near its destination, the cylinders are connected to a hydraulic pump. Then, the system can push and pull on the cylinders, tilting and moving the load for exact placement, up to a maximum of 1,500mm, the end of the cylinders’ stroke.
The standard package of four cylinders is available in three capacities: pull forces (each) of 60, 80 and 110t at a pressure of 700 bar. Push capacities are 10.5t, 14t and 22t respectively at 90 bar. Internal stroke sensors give the system a minimum error of 1mm. Oil flow at 700 bar is 4 litres/min. A parachute valve will shut off the cylinder in case of an abnormal speed increase if for example a hydraulic hose were broken.
The 80t capacity cylinders weigh 385kg each, or a total of 1.5t for a four-point pick. The cylinders’ side-on impact strength has not been tested, according to the company.
Enerpac offers three ways to control the SyncHoist system. With manual mode, users can control the stroke and also receive oil level, filter and motor overheating warnings. Extended manual mode includes a display showing the cylinders and their loads. Most sophisticated is the PLC control, which has a wireless remote control, touch screen, pre-programmable motions, data recording and all the features of the extended manual mode. In addition, it can calculate the centre of gravity of the load.
A system of four 80t cylinders costs around Euro 60,000 for the manual version, Euro 75,000 for the extended manual system and Euro 88,000 for the PLC-controlled system, though Enerpac expects many people to upgrade their systems rather than buy the most sophisticated version from new. ‘Our idea is the systems can be extended like a LEGO toy, you can buy a simple system and afterwards you can extend some capabilities depending on the base platform you have bought,’ a spokesperson said.
A total of five units have been sold since the first one was sold late last year. Jesus Gonzales, technical director of Enerpac Spain, invented the device in response to a customer request.
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The SyncHoist system was used for positioning of roof elements prior to welding in construction of the Palace of the Arts in Valencia, Spain, designed by Santiago Calatrava
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A SyncHoist system was also used for roof positioning of the Auditorium at Tenerife, in Santa Cruz de Tenerife in the Canary Island of the same name. The 60t capacity unit was used in this job
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The SyncHoist system relies on the crane only for rough positioning, and for load suspension. Once the load is close to its final position, hydraulic hoses are connected to a pump and the SyncHoist cylinders push and pull the load into the exact final location
