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DRAWBAR
Page 42
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COUPLINGS • Drawbars are enjoying a new period of popularity, according to Tom Dee, sales manager for Marcar Steel and Engineering which imports Italian-made Orlandi couplings. "Power-assisted couplings have helped," he says. "They reduce driver effort, increase safety and slash turn-round times," Orlandit main product for the UK is the E50 50mm coupling which features manual or remote-air operation and in-cab indication of coupling status. The air-operated coupling is small enough to fit between the rear-axle air bags on the towq vehicle, minimising the gap between trailer and prime mover.
The majority of UK drawbar trailers are centre-axle rather than steer-axle designs, says Dee: "They're easier to learn to handle and
reverse and the gap between truck and trailer can be smaller, increasing payload capacity."
However, loads must be evenly distributed; otherwise a see-saw action is created, placing great strain on the coupling.
Although other EU states oper
ate maximum-weight drawbars with a 50mm pin, most UK drawbar trailers use a 57.5mm coupling.
This was originally developed to suit the higher loads encountered in the Swedish forestry sector; it was popularised in the UK by market leader Fontaine V8G.
The 57.5mm pin is said to be better able to withstand the forces imposed by centre-axle drawbars, but this equipment is not interchangeable: trucks with a 5/.5mm couplings cannot be hooked up to trailers with 50mm pins. This could be important if you are mixing old and new vehicles on the same job.
Fontaine VBG's 795 57.5mm coupling has a replaceable bush which takes all the wear, and a one-piece housing that protects the pin from road dirt.
The German-made Cramer couplings, now imported by Holland Europe. also come with a 57.5mm pin size. Cramer couplings have freely rotating rather than fixed pins to even out wear. There are two locking pins to prevent shocks on the lifting mechanism.
Jost is developing a 57.5mm Rockinger pin and expects it to go into production early next year complete with optional air-operated remote control.