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Couplings – What Is A Coupling?
There are five main parts involved in the coupling: the tow bar, the tow ball and the ball mount or tongue that all attach to the tow vehicle plus the coupling body and the trailer ‘A’ Frame or trailer draw bar that form the attachment points on the trailer.
Some caravan and camper trailer manufacturers will provide an option for the type of coupling. There are various types but the most common is the on-road ball coupling.
Standard Quick Release Plunger Coupling
Most caravans and trailers come with a standard plunger ball mount coupling. These quick release plunger couplings are not considered to be strong enough to withstand the rigors of off-road use.
Some of the imported European caravans have a coupling that incorporates a stabilizer (See article on Sway Control Devices)
To avoid damage to the back bumper of the tow vehicle there are devices such as the Couplemate Hitchup Guide and Lock
What Is A Hyland Hitch?
The Hyland hitch, manufactured by Darren Hyland, is made to give the ball full articulation and it has full 360 degree sideway swivel so it is often favoured for off-road caravans and trailers. Proper setting up using a 3.5 tonne ball with a higher stem is required. The Hyland hitch head can be padlocked to prevent theft of your RV.
Camper trailers can be taken over much rougher terrain and the ‘up and down’ movement can be harsh and result in the bottoming out on the coupling and break either the tow bar, coupling or tow ball. Options are to use other types of couplings such as the ‘Treg’ or ‘Orac” .
The Treg, Trigg and Orac hitches are often used for camper trailers and not caravans due to the difficulties experienced in lining up the hitch pin to the rear of the tow vehicle. Camper trailers are more likely to be able to be physically moved to line up the hitch than say the heavier caravans.
What Is A Treg Hitch/Coupling?
The ‘Treg’ hitch has a polyurethane block which has some shock absorbing properties and stops noise and vibration from the trailer to the vehicle.
What Is A Trigg Poly Block Coupling?
The Trigg hitch is manufactured to ADR by Trigg Bros Pty Ltd of South Australia, for up to 2 and 3 ton use is similar to but should not be confused with the Treg Hitch.
What Is An AT35 Coupling?
Although now discontinued, the AT35 hitch coupling is rated to 3,500 kg and provides high articulation (70 degree min) in all combinations of movement. The AT35 coupling is often used by 4WD owners with a camper trailer or all terrain/off-road caravans.
Hitchmaster ® DO45
For caravans up to 4.5 tonne you also have the choice of the sturdier DO45 heavy duty off-road weight distribution hitch (WDH) compatable coupling. The DO45 incorporates a double automatic locking mechanism, plenty of simultaneous articulation in all directions and a patented self-aligning pin. New features are the dust cover which also ensures the coupling is correctly locked when fitted and a front cushion to prevent damage to the tow vehicle.
What Is An Orac Coupling?
The ‘Orac” type hitch allows full vertical movement and full 360 degree sideways movement as well.
What Is A Hitchmaster DO35 Coupling?
Vehicle Components of Geebung, Queensland, Australia have released their DO35 3.5T drop on coupling which provides plenty of articulation for off-road use. Vehicle Components also provide a number of option kits to suit use with weight distribution hitches (WDH). The Hitchmaster DO35 coupling meets all the Australian Design Rules (ADR) specifications and also has twin ADR compliant stainless steel locking mechanisms.
What Is A McHitch Uniglide Trailer Coupling?
The McHitch Uniglide Trailer Coupling has been invented by an Australian, Joe McGinnes, as an all purpose coupler for all types of trailers such as caravans, horse trailers and off road campers. Currently there are the 3.5 tonne and 6 tonne models with a 10 tonne version on the way. An important feature of the coupling is the use of a universal joint to handle all the vertical/horizontal movements with twisting movements being handled in the rear body by shock absorbing urethane bushes. The full body and the universal are both fully greaseable. McHitch adaptors are available for use with some existing market couplings.
What Is An OzHitch?
The OzHitch (or 50 second hitch) is an Australian Design Rule (ADR) and ISO 9001 approved off-road 3.5 ton hitch designed by Norm Hudson. It is designed with a tolerance for easy connection of the two halves of the hitch into the cradle. The OzHitch is made from steel and there is a choice of zinc plated or galvanised. The zinc plated OzHitch more suitable for painting. The designer states it has a very simple self locking system, lockable pin for security and a low profile to you’re your vehicle rear doors from damage. Maintenance involves a pump of grease in the grease nipple for the joints about every 1,000 km especially if travelling in duty conditions and some silicone spray on the pin.
What Is A Hitch-Ezy?
The Hitch-Ezy is a 5 tonne coupling designed by John Allsop and ADR compliant for the heavy-duty off-road caravan and trailer market.
Hitch-Ezy utilises a patented locking on method and the designer states this mechanism is easier to operate as the sleeve neither jams going on or coming off. Hitch-Ezy tows on a tow-pillar not a tow-ball and therefore does not have ‘slop’ and associated noise or the need for adjusting screws to remove any ‘slop’. The tow pillar is case hardened and chromed ball bearings are used. The designer’s opinion is that having the horizontal axis of rotation of the coupling pass through the axis of the tow-pillar is an important design feature that improves the ease of coupling. With Hitch-Ezy you can back the head of the tow-pillar into the open forward-facing mouth of the coupling’s sleeve and it will roll on ready for descent and full engagement. Subsequent downward forces from a lowered jockey wheel then act to self align the sleeve to the pillar rather than fighting against achieving this required alignment.
For off-road use the Hitch-Ezy uses O-ring seals to keep out dust and water and , when not in use, also comes with an aluminium dust cover and plug to protect the mechanism. Other features include grease nipples at the rear (to prevent any stone damage) and a coupling height of 117mm that will allow for rear door opening on 4WD vehicles whilst coupled to a caravan or trailer.
