For children who cannot pedal a conventional bicycle a US company decided to develop an alternative called ‘Step'n Go’, a three-wheeled bike that can be ridden by an up-and-down stepping action rather than the more conventional circular pedalling motion. Physical therapists were also involved at the design stage, and one suggested tilting the steering column back towards the rider, allowing him or her to fit the cycle more easily. However, there was a problem with the original flanged nylon bearing, which formed part of the steering column assembly. This was located on a pin, welded to the front axle, but because it had no self-aligning feature, it just fractured when the steering column was tilted.
Spyraflo came up with the answer - an oil-impregnated bronze, self-clinching, self-aligning bearing offering a ±5o self-alignment capability. This bearing was chosen for its rugged construction, but the self-lubricating feature offered an additional bonus as it also prevented corrosion of the carbon steel alignment pin. With the Spyraflo bearing in place, the steering column can be positioned where the rider needs the handlebars, without inhibiting rotation of the column. Most children probably will not use the full 5o self-aligning feature but in tests it was used to its maximum and the steering column continued to work flawlessly.
The self-clinching feature of the Spyraflo bearing also helped simplify assembly. As the bearing is pressed into the bore, the tapered sides force material up into an undercut below the flange. The serrations act as multiple cutting edges that increase the flow of material into the undercut. When finished, the flange of the bearing is flush with the surface, and becomes an integral part of the assembly.
Micromech distributes Spyraflo bearings throughout the UK and Eire.