The development of wheelchair lifts03 July 2023

coach PSVR requirements PLS

Richard Simpson hears how engineering practices from motorsport transformed coach wheelchair-lift design at PLS

Many coach operators appear to regard the wheelchair lifts required for PSVR requirements with a degree of trepidation. They add weight, expense and complexity to a coach, are another system requiring inspection and maintenance, and the perception among the cynical is that they will rarely be needed and probably won’t work when they are.

Like many stereotypes, there is perhaps a grain of truth in this, but one man who is out to tackle it head-on is Adam Beck, managing director of PLS (Passenger Lift Solutions), the West Midlands coach and minibus passenger lift maker.

Beck recalls his early days in the industry, when he watched a lift being deployed by a coach while the engine was running. He says: “I could see the nuts and bolts rotating with the vibration,” he remembers. “Threaded fasteners became the bane of my life, whether we are talking conventional nuts and bolts, or bolts and threaded components.”

Another worry was the failure of lifts when they were needed. He saw the designs of the 1990s as being easy to build but difficult to maintain or repair. This was anathema to him: with a background in racing karts at British Championship level, he knew that success or failure could be determined by the ability to rapidly change components between races – and he sought to bring the same philosophy to the design of passenger lifts.

“A failure in use is serious and needs to be put right fast. So I set out to produce lifts where there was no single component that couldn’t be replaced in an hour, tops. Lifts are built from above, but are usually serviced or maintained from underneath, so every component has to be easily reached and quickly detached and replaced.”

Threaded fasteners seem to occupy many of his waking hours. “You can move from nuts and bolts that are a fiddle to fit and remove, to tapping bolt holes into components, but that actually entails drilling a hole, countersinking it, tapping it, then re-tapping it and cleaning up after the component has had its finish applied. With 150 threaded fasteners on each lift, that’s immensely time consuming.”

Welding, too, has its drawbacks. He continues: “Skilled welders can demand high salaries, and are difficult to recruit and retain. Even the best welders can be inconsistent, and the energy cost of electrical welding is now highly significant. Robot welders are available, but not really suited to the varied product runs we produce, and the warranty and service backup offer is generally not good.”

PLS made its first coach lift in 1997, but was already making passenger lifts for the minibus market. “I’d say that the minibus market refutes the allegation that wheelchair lifts are unreliable. On a dial-a-ride minibus, they can do between 20 and 70 lifts a day: the minibuses are carrying six wheelchairs at a time. Our whole-life test is 55,000 cycles. In contrast, the wheelchair lift on a coach might be used once a month!”

So, is the perceived problem caused by lack of use?

Beck replies: “No, I’d say that it’s caused by lack of practice and training among drivers. They might not know where the remote control has been put, or it might have been dropped or otherwise damaged. They might not be able to remember how to fold the passenger handles or the floor away manually before the lift is stowed.

“Regulations dictate that we use pictograms instead of written instructions as some users may not understand written English… the trouble is, not all users understand pictograms,” he smiles.

“You have to be trained to operate the lift, but not everybody is. National Express checks the operation of the lifts on its coaches every day, so the drivers are well-practised, but I get the impression that some operators specify lifts because they have to, and hope they will never have to use them.

“Most of the calls we get to our helpline are not for failures in the lifts themselves. They are for lost control units, or from drivers who just don’t know how to use the lift. Minibus drivers who have graduated to coaches generally do far better, and we are also working on a series of ‘how to’ instructional videos.

“In terms of actual problems, most are electrical and result from failures of sensors that operate interlocks in the coach itself. For instance, the parking-brake must be applied and the prop-shaft must be stationary before the lift can be deployed. If the prop-shaft sensor is defective, then the lift won’t work, but it’s not a fault in the lift,” according to the MD.

Do coach lifts fail because they become dirty or corroded? He responds: “It’s not a problem for most coach lifts because they are situated in the ski locker to the rear of the vehicle or other enclosed spaces, and are protected from dirt and water. On the minibuses, on the other hand, they are under the rear floor of the vehicle, where the spare wheel would be on a van. They get plastered!

“Coach lifts at the front entrance are more exposed, and we can protect these against corrosion by using zinc-plating instead of powder-coating.”

PLS has another counter to corrosion: ACF-50. This is an anti-corrosion and electrical system protectant and lubricant developed by Lear Chemicals in Canada for the aerospace industry, which is widely used by the UK’s motorcyclists to protect their mounts from winter corrosion. “It’s an absolute gamechanger,” reports Beck, a motorcyclist who discovered its when maintaining his own bikes.

Using ACF-50 virtually eliminates corrosion, making components easy to change in service. This ease of maintenance also extends to the use of proper aircraft-quality wiring plugs, with every wire numbered as well as being identified by colour-coding. Hydraulic rams are secured using pins and R-clips, making them easy to remove and replace. Microchip use is minimised, hydraulic and electrical/mechanical systems being easier to diagnose and fix. Screwed fittings are marked with paint to identify loosening parts.

PLS has also done its best to streamline maintenance processes. “LOLER inspections are compulsory on all lifting equipment, every six months. It’s a non-invasive inspection by a competent person to ensure that the lift will be safe to use for another six months. We combine that with a lift service and a weight test. The weight test is only compulsory on new installations, and it really covers the structural interface of the lift with the coach itself, but we do it every six months anyway. The whole exercise takes the coach out of service for only half a day, so I don’t think you can say the lift is particularly maintenance-intensive.”

Richard Simpson

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