Iveco NEW DAILY, Instructions Manual

Page: 47 / 240

NEW DAILY
–
CHASSIS INTERVENTIONS
CHASSIS INTERVENTIONS
2.6 INSTALLING THE TOW HOOK
23
–
Printed 603.95.789
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1 Ed. - Base 02/2014
Types of hook
The following types of hook are available:
1. ball-joint
2. automatic
Hooks with pins can only be installed on the truck version and require the use of a suitable cross member.
Both types, if not supplied directly by IVECO, must be type-approved in compliance with current legislation.
Table 2.11 lists certain data for the tow couplings available from the production line.
Table 2.11 - Type-approved hooks
Type Class D [kN] DC [kN] V [kN] N˚ ECE type approval
GS500 A50-X 22.5
–
25 E11 55R-010533 ext 02
GA381 S 22.5
–
25 E11 55R-011613
Drawbar couplings for centre axle trailers
Centre axle trailers are defined as those that have the drawbar rigidly connected to the frame and the axle (or more close axles)
placed at half the length of the same chassis.
Compared to the articulated drawbars, the rigid drawbar acts on the drawbar coupling with the increase of the static vertical loads
and, in the braking phase or in the oscillations caused by the road surface, the increase of the dynamic vertical loads. By means of
the hook, these loads lead to increases in the torsion of the rear crossbar of the vehicle, as well as push-ups on the overhang.
The use of centre axle trailers therefore requires the use of suitable towing hooks.
The values of the towed weights and vertical loads allowed are listed on the technical documents of the drawbar coupling manufac-
turer and on the part manufacture plate (see DIN 74051 and 74052).
Towing hooks that bear special approvals and with values greater than those listed in the above standards may be used. However,
these towing hooks may pose restrictions in relation to the type of trailer used (e.g. drawbar length); In addition, the drawbar may
require reinforcement for the towing vehicle as well as larger counter chassis profile section.
For mechanical coupling devices for trailers with a central axle, refer to the following formulas:
D
C
= g (T • C) / (T + C)
V = a • C (X
2
/ L
2
)
D
C
= representative value of drawbar class [kN]. This is defined as the determination of the theoretical reference value for hori-
zontal load between tractor
g = acceleration of gravity [m/s
2
]
T = maximum weight of tractor
R = maximum weight of trailer
S = value of vertical static load that, in static conditions, is transmitted to the coupling point. S must be
≤
0.1 x R
≤
1000 kg of the
trailer
C = sum of maximum axial loads of the centre axle trailer at full load. It is equal to the maximum mass of the trailer decreased by
the vertical static load (C = R - S)
V = value of the theoretical dynamic vertical load [kN]
a = vertical acceleration in the area of the drawbar coupling/hook. in function of the rear tractor suspension, use the following
values:
●
a = 1.8 m/s
2
of air suspensions
●
a = 2.4 m/s
2
for other types of suspensions