Well into the second half of the last century, vehicles belonging to the middle and even upper class were still equipped with coil springs and rigid axles (fig. 1). Still today this combination emerges with heavy jeeps. It is further developed than the rigid axle combined with leaf springs (fig. 2), but the clear disadvantage of both are the large non-spring mounted masses.
How it works
The picture shows a simple wheel suspension. The diagonal shock-mounts make a deeper floor or small wheel housings possible. At the connection points of the shock-mounts and the axle, the two lower semi-trailing arms are mounted. More above, somewhat more centered, the - usually shorter - upper semi-trailing arms are mounted to the axle. The axle is no longer twisted while braking or accelerating. A Panhard rod is used for side guidance, stretching from the down left with a little slope to the right, towards the floor of the car. It exposes a relatively long spring travel, because during middle load it stands horizontal, and during full load in reverse angle, thus downwards at the right side. The picture displays also the simplified guidance of the brake hose with rigid axles. There is just a hose to the rear. From the distributor there are rigid lines to the visible drum brakes. Another feature of the brake is theload-sensitive brake pressure regulator. Via a tracer to the left a shaft is twisted, and thereby, with little weight on the rear axle, the brake pressure in the back is diminished. Vehicles with anti-lock braking system do not need this device, naturally.
Undercarriage 1
Rigid Axle (driven)
