London, Ontario - After putting in eight years of work and $60 000 (R680 000) of his own money, Canadian commercial driver-turned inventor William Liddiard posted this Youtube video under the simple headline: "It works!" These, he claims, are the first omni-directional wheels that can be fitted to a conventional car, without building the car around the wheels.
As the video shows, the Toyota Echo that's wearing his proof-of-concept prototypes can literally dance its way into and out of any tight spot - and then be driven just like any conventional car on the highway.
How'd he do that?
The principle is actually quite simple: each rim has two deep grooves, each holding a tyre shaped like a doughnut - or a giant O-ring, if you want to get technical about it.
Lock the tyres in place on the rims, and the Echo drives like any normal car - but rotating the tyres sideways in their grooves, inwards or outwards as the case may be, provides the sideways component, and a combination of the two allows the car to move in literally any direction. Or, indeed, just stand there and rotate as if it was on a turntable.
Sceptics have pointed out that the car could tend to drift sideways at highway speeds, but a design error by Liddiard has had the side-effect of making that impossible.
He grossly overestimated the power needed to move the car sideways, and so geared the motors to supply a total of almost 33 000Nm of torque, which makes the car move sideways very slowly but firmly holds the tyres in place, without any need for mechanical locks, when the system is switched off.
Wear issue
These are only prototypes, he acknowledges; in order to rotate in their grooves the rubber compound has to be softer than on conventional tyres, so tread wear becomes an issue. Tyre pressure monitoring, or indeed pumping, also becomes a problem on tyres that have no sidewalls.
But this genie is now out of the bottle; it's too late for anybody to say that Liddiard's idea doesn't work. He's now looking to partner with one of the big tyre companies to production-engineer his omni-direction wheels, but says he will continue development work himself, with or without corporate investors. Respect.