Street to the sky

5 June 2012

Street Crane has equipped an aircraft wing manufacturing facility in Belfast, Northern Ireland with two overhead cranes for accurate positioning in three dimensions. Cristina Brooks reports

The 'moonbeam' cranes will produce composite wings and components for Bombardier's CSeries commercial aircraft family and a Learjet 85 business jet, filling orders for 138 CSeries airliners.

They have four suspension points and a pin-jointed system for flexing the crane beam along with the movable roof. Street Crane's 'moonbeam' technology has been in development for the last 25 years, and it says it has installed similar designs for British Aerospace and Princess Yachts.

The Bombardier cranes span 20 and 25m respectively between the crane rails. The rails are integrated with the roof structure, and equipped with cantilevered extensions to give the system greater reach.

Street Crane said that when installing the crane beams, it took care to reduce overall crane depth and give maximum working height. The beams are underslung from the travel rails while hoists are underslung from the crane bridge.

Street Crane supplied ZX64 hoists giving a 6m height of lift for all of the cranes.

It equipped the primary production area with a four-axis, 20t single girder crane, with a radically different design from what is typical in the market, Street Crane says.

Street Crane explained that the 20t 'jiggle' crane uses its 15t and 10t hoists for precise positioning.

"On the jiggle crane, the first hoist takes most of the weight of the wing and the second hoist ┬║provides lateral adjustment allowing the wing to be rotated by 600mm and an additional plus or minus 300mm rotation around the beam axis," it said.

"This multi-span crane has four suspension points and an overall span of 64m with a cantilever at each end. The box beam design gives the strength and rigidity required, and is pin-jointed to give flexibility of movement to the crane beam so that it can flex with movements in the roof."

In the assembly area, an 8t underslung double girder crane can rotate wings just over half a revolution (200 degrees) on twin rotating hoists.

Street Crane said that the remote controlled positioning system could move at variable speeds.

"Hoist and travel motion travel speeds are variable from 400mm per minute to 20m per minute with sensorless current vector control for accurate positioning with smooth movement," the company said. Radio remote control was included with the order to provide safety and ease of use, along with push button pendant as a back up control."

Load capacity restrictors, audible alarms and amber flashing warning lights are included for added safety.

The Bombardier's system ensures wings can be moved along the 52m pin jointed crane bridge. "The turntable is equivalent to a small 5m crane running on a circular track between the main crane beams," Street Crane said.

Andrew Pimblett, Street Crane's managing director said, "This is a highly unusual crane design that is probably unique in the UK, if not the world.

"We have a similar set up at Heathrow Airport with an 80m span double girder underslung crane, but not of the same level of sophistication as the technology at Bombardier."

Crane rails are an integral part of the roof structure, rather than being attached to the building columns or supported on gantries.
Hinged, multi-span cranes are unusual but essential in aircraft production where wide bays are common.