 Utility Vehicles
Today's coaches, after all, double-decker with large engines and much equipment need trailing axles due to the high weight and the by law limited axle load. They are available in different versions, rigid or as
independent suspension, active or passive steerable, always permanently on the road or liftable e.g. when reversing. At the shown above, you can recognize the track rod and the hydraulic element for steering.
They have, already for reasons of rationalization great similarity with front axles, however, those of city buses, and create like this also in the coach place for a deep floor. The big theme, except the weight
distribution, is of course the reduction of tire wear. Anyone who has ever experienced, how a truck tire is drawn half crosswise under load on the road, can better understand this technique here.
Perhaps you have not spent yet so much time on the technique of trailers. They are said to be indeed handier, e.g. when reversing in spite of its length as vehicles with two-axle trailers, if there are not two
axles with a small distance. Puzzles with possible scenarios are performed as well by manufacturers as in conception of something narrower plants.
We wonder how actually a steerable trailing axle works. For trailers with less payload, it may be the only rear axle, well suited in supplying supermarkets, e.g. near the town center, if such a thing still exists.
Easy to imagine is a purely hydraulic or electro-hydraulic system, as it is visible in the picture below and already been described in this book.
There are also simpler systems, e.g. those in which the wheels of the axle run after as case of the shopping cart. Of course, the must be fixed when driving backwards. Or a rod of the fifth wheel clutch runs to
the rear and steers so mechanically the wheels. Then is more effort necessary when connecting such a semitrailer than when reversing.
Almost aesthetically beautiful is this steered and via double universal joints driven axle. The hydraulic of the dampers can be influenced from the outside.
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