Spanish tower crane company Jaso has announced the second crane in its new high capacity ‘Low Top’ range - the 48 tonne J800.48 – which follows the 64 tonne J1400 which was unveiled earlier this year.
The J800 can take its 48 tonne maximum capacity out to a radius of 23 metres or handle 5.1 tonnes at its 80 metre jib tip. Jaso has dubbed the new models as ‘Low Top’ cranes, as they are clearly not a flat tops, however the tower head is a great deal shorter than a typical hammerhead crane, being just 4.7 metres high and protruding just over 2.2 metres above the top chords of the jib. The heavy duty pendants are also very short running from the tower head to an attachment point at the end of the second jib section just under 23 metres from the front of the tower.
The company claims that as such it is dimensionally similar to a true flat top, and said: “When you compare like with like there is actually no difference in the clearance heights of flat tops and our Low-Top, because flat top designs need deeper jibs to compensate for the pendant height in order to maintain the same strength. Maintaining the separate pendants provides improved performance and less deflection thanks to the extremely short but strong pendants.”
The rest of the jib can be built up with a variety of sections as short as 2.5 metres, for a wide range of jib lengths. The counter jib is of four modules for a variety of possible configurations with lengths from 18.6 to 28 metres.
The maximum free standing height with the standard 2.16 x 2.16 metre tower system is 73.6 metres, with the tower built in 5.6 metre sections. The stronger TSP20-5.6 tower can also be used, it has the same cross section but can be built to a free standing height of 101.7 metres for jib lengths up to 23 metres or 90.5 metres with the full 80 metres of jib.
The J800 trolley can be single reeved - for a maximum capacity of 24 tonnes and 4.1 tonnes at 80 metres - or double reeved for the maximum 48 tonnes and 3.3 tonnes at 80 metres. A special single reeved trolley is used for the maximum jib tip capacity of 5.1 tonnes at 80 metres.
A choice of 150hp or 180hp motors offer line speeds up 150 metres a minute, while the Lebus grooved hoist drum can store enough cable for 455 metre hook heights with single reeving or 277 metres when double reeved.