Finger Steering

Assignment

At the time when no-one considered the steering being important in relation to accident consequences, a relatively simple steering was possible. Even in famous old-timers, like the Mercedes SSK there was, next to the relatively large in-line six-cylinder engine, not much space. Thus the steering wheel was connected by a shaft to the steering gear, mounted right up front, which then transferred the steering movements (with a rigid front axle) to a one-piece tie-rod. Repairing was also very difficult because the shaft had to be completely dismounted, this was typical for vehicles with a steering column without a flexible-joint disc.

Function

The steering shaft is more-or-less an extension of the steering column. Now distinctly increased in diameter, it carries a few curves of trapezoid threading which, in each case, end abruptly in a curve. A cone, which itself, is held by tapered roller bearings in the steering arm, meshes into the threading. Should the steering shaft be turned, the steering arm also turns, indeed, with a considerable amount of reduction ratio, in the area of approx. 20:1.An adjusting screw, working axially on the steering shaft screw, allows the setting of the amount of play between cone and trapezoid threading. However, this only functions well as long as the cone is actually travelling in the threading. If it is flattened through external influence on the steering, it develops, instead of rolling, a sliding friction, and this is normally the beginning of the end.

To check this, the connection to the steering linkage should be loosened, and then the steering wheel turned from lock-to-lock. In this case, no points of increased resistance should be apparent. Sometimes, after loosening the lock-nut (on the far right in the above figure), adjusting helps, whereby, the whole steering range should once again be checked. Generally, a compromise is necessary, between some play in the center position, and a certain amount of stiffness in the steering operation. If nevertheless, noticeable points still remain, the disassembly and repair are inevitable. 09/09