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When it comes to trailer couplings, kingpins and fifth wheels invariably steal the limelight but what of the other form of coupling, the ball hitch? FleetWatch asked Les Austin, managing director of Avmark, suppliers of ball hitches to the local truck and trailer industry to spell out the history and benefits of this type of coupling. 

"Tow hitches have probably been around since the first time August Fruehauf transported a boat to the nearest sea-port atop his first self-made semi-trailer, towed by a converted Model T Ford in 1914. Despite being used extensively in light duty trailer transport, ball type hitches only really made an entrance into the South African heavy duty transport arena some 18 years ago. Surprisingly, European trailer manufacturers are only now starting to realize the advantages of this type of hitch, when we already have about 4000 in operation on our roads today. 

Making sense
"Recent changes in the SA Road Ordinance, designed to favour the use of interlinks and single truck/semi-trailer combinations, have caused considerable shrinkage in the overall hitch market, but ball hitches continue to rapidly increase their market share in this country, where there are two distinct types of ball hitches: the first, where the 'ball' is mounted on the drawn vehicle, or pup trailer, and secondly, where the 'ball' is mounted on the drawing vehicle, or the semi-trailer, in the case of a combination of three vehicles.

"The 'Cimex' Pup Hitch has the ball mounted on the pup trailer (where the kingpin of the semi-trailer would normally be). This hitch was introduced in 1988 and is by far the leader in the tanker pup field. All road tanker operators of note have a high proportion of Cimex hitches in their fleet. These locally designed and manufactured hitches are known for their safety and reliability and are remanufactured and reconditioned as part of an ongoing service exchange operation.

"With the change in the SA Road Ordinance, increasing overall combination length of a truck/tractor and semi-trailer to 18.5 meters, a number of transport operators began fitting pup trailers behind their tridems, where there was now some space, but not enough for a drawbar trailer. There was, however, no hitch on the market that could accommodate the downward loads imposed by the rigid drawbar design of the pup trailer. Avmark met the demand by introducing the 'Saf-T-Ball' hitch, where the ball is mounted on the drawing vehicle. 

"This hitch was originally designed for use in the forestry industry, where it continues to be extremely successful. It has since been adopted for general road transport pup trailers because it is capable of withstanding considerable loads in both vertical and horizontal planes (many pup and centre pivot bogie trailers are still seen every day on our roads with types of imported hitches that were never designed for vertically imposed loads). Furthermore, the hitch is now popular in drawbar trailer operations, including tipping drawbar combinations and three and four axle drawbar combinations in on/off highway applications.

"Tests have been carried out on these products by a leading scientific research institute (in the absence of any current SABS specification ) to more than twice the load required for a drawbar or pup trailer application, since DIN ratings, given for imported hitches, do not accurately reflect the situation in SA, where our road ordinance allows nearly 50% higher GCM. The thousands of ball hitches now in daily operation in South Africa and neighbouring countries cover an estimated 80 000 km every working day.
 

From this...

...to as good as new

Easy to see the wear and tear on this Cimex hitch (top) to as good as new - a fully overhauled Cimex hitch won’t break the bank.

Ball advantages
"Ball hitches allow for smooth coupling and eliminate much of the backlash which causes drivetrain damage. The degree of articulation of this hitch makes it extremely suitable for off-highway applications, as well as enabling easier coupling on uneven terrain. 

"All components and wearing parts of this hitch are 'visible', making it easy to spot any parts in need of attention. What's more, the relatively low initial cost of the hitch, as well as the low cost of the few wearing parts and its long working life, makes it a viable economic proposition for heavy transport.

"A more recent addition to the range is the 'Auto-locking ball hitch', designed primarily for drawbar trailers. Currently available in two sizes, 80mm ball for trailer GVW up to 22 000Kg and 90mm ball for GVW up to 45 000Kg, this hitch has a 'gravity operated' locking mechanism, few wearing parts and no springs or enclosed components, making maintenance very simple and cost effective.

Home-brewed ball
"In these times of mass production and global marketing by multinational corporations, it is probably a little unusual to find, in a developing country, an industrial product of local design and manufacture being competitively marketed.

"These ball hitches however, effectively service a niche market in the absence of any other suitable product designed to withstand the harsh South African and sub-Saharan operating conditions."