Don-Bur launches expanding roof trailer

UK-based trailer and rigid body OEM, Don-Bur, has manufactured a lifting deck tri-axle trailer design with an expanding roof for a parcel company.

The new product is reported to provide 7.8 per cent more head room on the lower deck during loading but keeps overall height to 4.5m when in transit to avoid low bridge restrictions and retain a more idealistic aerodynamic profile; expected to result in a 5.0 per cent fuel saving.

Don-Bur claims to have invented lifting deck trailers in the late 1980s which continue to 'rise' in popularity due to high payload volume and rapid turnaround at the bay without additional specialist bay equipment.

“The simple premise is a secondary deck that, when loaded in its lowered position to suit bay height, then raises via hydraulics to a second height allowing another full payload to be loaded underneath it,” said Don-Bur Group Marketing Manager, Richard Owens.

“However, straight-frame lifting decks in particular have their aperture heights limited between the height of the fifth wheel and overall height and this restriction can cause challenges with head height for loading operatives.

“The new expanding roof overcomes this by allowing the loaded second deck to raise much higher than normal during lower deck loading. After loading and before transit, the roof and deck lower again to a position where gaps over the load are minimal,” he said.

Don-Bur also commented on the aerodynamics of the new trailer design. By keeping the roof 350mm lower than a full height double deck it is reported to reduce drag force by an estimated 661 Newtons. Don-Bur referred to a case study which measured at a speed of 56mph (90kph) – a comparison made between base trailer at 4,850mm high and a test trailer at 4,500mm high assuming all other proportions are the same; coefficient drag was calculated to reduce due to improved drag profile. Case studies studying multiple fuel trials relative to drag force have indicated that drag force represents approximately 33 per cent of all other resistant forces including surface friction, tyre deformation and drive line resistance.

The roof attachment system, according to Owens, is one of the most ingenious parts of the design.

“During part of the loading operation, the second deck has to move up and down freely and independently of the roof – however, as the deck over-extends upwards to generate more head height, so too does the roof to prevent the upper load being crushed.” said Owens. “Not only that, but the roof then has to forcibly clamp back down onto the body structure, to ensure the correct lower height and prevent water ingress.  Don-Bur has developed and innovative solution to this challenge and, for this reason, has applied for patent.”

The new trailer design, Owens said, is ideal for businesses that operate with lower cage heights, pallets or loose loads.

“It could also be applied to companies that switch between operation in Northern Ireland (that has a 4,650mm overall height restriction) and the UK mainland; the latter having a 250mm potential height benefit equivalent to an 8.6m³ volume increase,” he said.

“This development was in response to a customer's needs as many of our innovations are,” said Don-Bur Chairman, David Burton. “We were very proud to deliver a unique, simple and robust mechanism that gives the client greater flexibility, improved safety, enhanced aerodynamics and optimum value.”

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