2-28 CHASSIS MODIFICATIONS E UROCARGO Euro 4/5 Computational example of the class of the connection device for centre-axle trailers We consider a new vehicle with maximum mass 10 t that has to haul a centre-axle trailer of 9 t with load surface length 8 m and theoretical drawbar length 7 m. Therefore from the data 1. S is equal to 0.9 t that is the lesser of the values 0.1· R = 0.9 t and 1 t 2. x 2 / l 2 = 64 / 49 = 1.3 we obtain:
D C = 9.81 · (18 · 16) / (18 + 16) = 84 KN V = 1.8 · 1.3 · 16 = 37.5 KN Centre-axle trailer Towed vehicle equipped with a towing device which cannot move vertically (in relation to the trailer), and in which the axle(s) is (are) positioned close to the centre of gravity of the vehicle (when uniformly loaded) such that only a small static vertical load, not exceeding 10 % of the maximum mass of the trailer or 1000 kg (whichever is the lesser) is transmitted to the drawing vehicle. Centre-axle trailers are therefore subgroups of trailers with a rigid drawbar.
Figure 2.10 116774 Length of the load surface of the trailer and theoretical length of the drawbar TBD-110 2.6.4 Centre-axle trailers (with rigid drawbar) Using centre-axle trailers (towing with a rigid drawbar with one or more axles brought closer) compared to towing with articu- lated drawbars causes an increase in the bending stresses on the rear chassis frame overhang and torsion strain on the rear drawing tie, because of the static and dynamic vertical loads that the drawbar exerts on the hook (for instance in the phase of braking and for the oscillations determined by the road surface).
On vehicles for which trailer towing is permissible and in compliance with the values defined by IVECO for each model, it is possible to define the towable masses with centre-axle trailers and the vertical loads on the towing tie according to the dimensions of the existing jig on the rear tie of the vehicle (see Table 2.10). In addition, when there are long rear overhangs, depending on the towable masses, it can be necessary to uselarger subframesections (see Table 2.10) than those normally required.
When using centre-axle trailers, make the connection between the chassis frame and subframe, from the rear end of the overhang to the front support of the rear suspension, with longitudinal and transversal plates (see Figure 2.13). Installing a towing device Base - January 2008 Print 603.93.431