Radical new hitch sets latest standard for manufacturers
'Roller-Hitch' design boosts lift capacities
Published 03/08/2010 | 05:00
Meath engineering firm, Dromone Engineering, has unveiled a new design of pick-up hitch for tractors, adding to its already extensive range of hitches supplied to both tractor manufacturers and farmer users.
The 'Roller-Hitch' design is a departure from traditional units that employ lift rods attached to the tractor's three-point linkage top arms to lower and raise the hitch in hooking up to a trailer.
The new design had to meet several criteria. Firstly, it had to be link-less (no lift rods), visible from the driver's seat when hooking up, have effective ground clearance, be capable of meeting lifting requirements and, of course, be reliable.
This is achieved by using an integrated double-acting ram, heavy-duty chains similar to a forklift mast and a sliding cartridge mechanism. As the hitch's hydraulic ram moves the cartridge mechanism outwards, it is guided in a slot at the hinge point of the hitch, keeping the cartridge captive. At the hook end of the cartridge, the heavy-duty chains on each side of the hitch are guided over two rollers on each side, which are attached to the fixed part of the hitch bolted to the tractor and the cartridge hinge point.
It is the rearwards (outwards) movement of the cartridge that feeds the chain out over the rollers and allows the hook or ball to be lowered and extended rearwards at the same time. In one motion, the hydraulic ram lowers and extends the hitch rearwards, ready to attach to a trailer or trailed implement.
Lifting capacity of the design is in the region of five tonnes, which is well in excess of the carrying capacity at the hook of around three tonnes. This extra capacity allows some reserve for the unit to lift when fully extended, but not enough to do any damage to the keeper if the trailer is hooked up incorrectly.
Dromone Engineering's Patrick Duffy says that the Roller-Hitch design came about because of difficulties in fitting the traditional design of hitch to the Fendt 900 series.