The happy hook-up

  • Retired engineer John Abel’s new trailer hitch invention not only takes the hassles out of towing, but makes it much safer, too. Image credit: Sean Woods
  • A hydraulic cylinder diagonally links the mechanism’s two pivoting pipes (situated beneath the trailer) together. When receiving current from the solenoid, the cylinder locks, forcing the two pipes into position, thus preventing the trailer from contra-articulating or jack knifing. Image credit: Sean Woods
  • Abel made Meccano models to visualise his design. Below: The new tow hitch makes the old “ball and chain” redundant. Bottom: Reversing with the new trailer hitch is a non-issue. Image credit: Sean Woods
Date:28 October 2012 Tags:, , ,

Towing can be nerve-wracking, particularly when reversing. A new trailer hitch design aims to change all that. By Sean Woods

Faced with a charging elephant, John Abel knew his only realistic shot at getting his family to safety involved slamming into reverse gear and beating an extremely hasty retreat. Problem: a trailer was hitched up to the rear of their car. There was no escape.

Fortunately, the angry jumbo was all trumpet and no tusk. Shaken but safe, the Abels could continue their Kruger National Park journey.

But a seed had been sown…

Yet it took years before things fell into place. The scene: mid-intersection. A hapless driver becomes increasingly tangled up in a trailer. Gauteng’s take-no-prisoners rush hour traffic bears down on her. Abel looks on, thinking: “There has to be a better way.”

After about eight years of work, this retired engineer reckons he has found the better way. If he is right, legions of drivers will be in his debt.

Unless you get plenty of practice, chances are the mere thought of reversing a trailer is enough to make you break out in a sweat. Abel believes his breathtakingly simple invention could make all of that history. It makes trailer handling as stress-free, he says, as driving an unhitched car.

Not being the kind of man to take retirement lying down, he started puzzling over various designs several years ago. “I was convinced that a simple concept would work,” he says. But he was aware of the need to ensure it made financial sense. “As I’d already patented a number of designs over the years that had all faded away into obscurity because they weren’t economically viable, I knew I had to take this aspect into consideration, too.”

Considering that countless inventive minds have tried – with varying degrees of success – to solve the trailer reversing conundrum, it’s astonishing that Abel took just a week to crystallise his design. But hard work lay ahead. “Although the concept came to me quickly, it then took two years of me trying to prove myself wrong before I truly realised that it was feasible.”

Using basic Meccano models to visualise his design, he worked out the fundamental flaw in conventional trailer hitches: the articulation point is located between the towing vehicle’s rear wheels and the trailer’s wheels. When reversing, this means the trailer gets pushed from behind its wheels, so it turns in the opposite direction to the towing vehicle.

Abel reasoned that temporarily locking this articulation point in place when necessary would stop the trailer contra-articulating while being pushed in reverse. Instead, it would follow the same path as the towing vehicle. Another benefit would be no jackknifing under hard braking. Towing would be much safer and stress-free.

Link rethink
The concept involves a totally new tow hitch mechanism. A cylindrical bar connects the trailer to the tow vehicle, with two parallel pipes (capable of pivoting at the tow hitch) connected to it perpendicularly. These pipes in turn run underneath the trailer and are attached to the chassis behind its axle.

A hydraulic cylinder (acting as a brake, not a pump) diagonally links both pipes together. Finally, the hydraulic cylinder is connected to a solenoid that draws power from the vehicle’s brake and reverse lights via its trailer plug.

When travelling forward, Abel’s new tow hitch operates just like its conventional cousin. However, as soon as the tow vehicle is put into reverse or the brakes are applied, things change. Current is sent via the vehicle’s trailer plug to the solenoid, causing the hydraulic cylinder to lock. This, in turn, pulls both parallel rods into position behind the tow vehicle and fixes them firmly in place. Besides preventing the trailer from contra-articulating while reversing, this prevents any chance of jackknifing during an emergency.

“The irony of it is that it’s such a simple design,” Abel says. “There’s not much one can say to describe it, really.”

Simplicity aside, what makes Abel’s invention truly amazing is that it works on all trailer sizes and types: from your small garden-refuse variety, to large 4×4 and boat trailers and caravans. Heavy-duty truck and trailer (fifth wheel) units with pneumatic or hydraulic couplings can also be accommodated, but require some extra engineering input.

Taking on the world
At first, Abel was interested in securing a local patent only. That was soon to change, though. On his first visit to his patent attorneys, when he described his design, they liked the idea in principle but remained sceptical. They wanted to see a prototype before taking anything seriously. “I completely understood where they were coming from,” he says. “About 280 patents have been lodged – all of them attempting to reverse trailers – since 1940. Once they saw my prototype in action, they immediately suggested I patent it internationally.”

That meant approaching the Belgium-based Patent Co-operation Treaty (the world patenting authority) for assessment. Their final verdict was a resounding yes, giving him the highest possible scores for novelty, inventiveness and industrial applicability.

Now that Abel has secured his international patents, he’s looking for partners to help bring his product to market. “Ideally, I would like to sell licences to companies that are prepared to refine a few aspects of the design to make it marketable, as I can’t do it all on my own,” he explains.

To find out more, contact Abel via e-mail at
Video: Retroline’s auto-sensing, anti-jackknife trailer

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