THE DEFINITIVE TRUCKING SITE

September 2008

Drawbar trailers are gaining in popularity across a number of applications as are pup trailers. While some transporters opt for hinged drawbars on longer trailers, a pup trailer is usually equipped with a rigid drawbar which needs a ball-hitch coupling system to manage the downward force exerted by the drawbar. There is much room for improvement as far as maintenance of these couplings is concerned, says Avmark’s Les Austin. 

As suppliers of tow hitches, road safety is uppermost in our minds and driver ability along with correct maintenance practices are always areas needing attention,” says Austin. 

“The attitude towards vehicle maintenance does not appear to have changed  over the years. In general, fleets have become larger and operators are under increasing pressure to retain margins due to capital equipment and fuel price increases and as a result, maintenance has suffered, only being carried out when CoF time comes around.” 

Good lubrication does not equate to good maintenance. This hitch is well greased but the very important “gap” between the dome cap and the locking stud has been “adjusted” with the help of a welding machine, instead of replacing the cup (a plastic insert)	Hard labour in the forestry industry. The level of punishment exacted on hitches in this industry is severe, and jackknifing, as shown on both sides of this hitch, is common. Maintenance in this industry is different. Don’t worry about on-going maintenance, but have the unit reconditioned before it becomes unsafe !
A “veteran” of service in Zambia--- this hitch has been reconditioned and is now back in use. Avmark has documented proof of hitches in well maintained highway operations covering four years, and 1.25 million km, before reconditioning.	The bush in the swivel lock has long since disintegrated resulting in the locking stud floating about freely and no longer vertical, or effective.

The ball section of the SAF-T-BALL coupling, fitted to the drawing vehicle, of which some 2500 are now in operation in Southern Africa. The mounting hole size and spacing are the same as most heavy duty imported hitches.

Adapting for safety 

As a local manufacturer of tow hitches, Avmark has the ability to meet market needs swiftly and Austin cites his new ball joint coupling system as an example. 

“We have done away with the adjustment of the swivel lock stud and welded it to the swivel lock body. In the two years since the introduction of the replaceable (longer) stud to compensate for cup wear, only six have been sold, which suggests some serious maintenance oversight.” The release of the longer stud did coincide with the introduction of a plastic composite cup as an option over the more expensive bronze version, says Austin. 

“It’s cheaper and this is no doubt the reason why they have outsold the bronze cup. However, ball hitches are inherently low maintenance products and with only a few wearing/replaceable parts in the whole assembly now, there is little or no excuse for not doing basic maintenance, particularly because only minimal skill is required for basic parts replacement.” 

To reach all users of Avmark products is a difficult task says Austin, especially because many are sold via the ‘trade’, be that trailer builders or parts suppliers. “Trying to educate the entire industry can feel like we’re doing the unmentionable into the wind and therefore, we prefer to make changes to our products to suit market conditions and practices.” 

Some of the maintenance practices Austin has seen are quite frightening. One he refers to skeptically as the ‘African locknut’.

“This tool is more commonly known as the welding machine. We actually came across an operator who welded the jaws of a 5th wheel together in the hopes of extending its working life!”

By way of a solution to such horrific practices, Austin contends that “whether it’s insurance companies coming down harder on negligent operators or more stringent examination at truck checkpoints, no amount of officialdom will ever solve this problem. The answer lies within the industry itself.” 

Roll on self regulation. It really is the way to go.