The specific value for the capacity of each fifth wheel kingpin is the D-
value that can be read on the bottom of the kingpin Fig. 1. The weight of
a vehicle alone is no equivalent for the forces that occur in the coupling
devices. First, the sum of the influencing factors or their relation
determines the force that acts upon the coupling device. This strength
(called shaft strength or D-value for short) is connected to the fifth wheel
vertical load, the weight of the fifth wheel tractor and the weight of the
semi-trailer and will also be disclosed in the type testing.
Calculation according to ECE-R55 chapter 2.11.1
The D-value can be calculated using the
following formula Fig. 4.
D-value calculation formula
Formula symbol, Fig. 4
Definition of terms
D
D-value in kN
g
Gravity; g = 9.81 m/s
2
T
Maximum permissible laden weight of
the tractor in t
R
Permitted total weight of the
articulated trailer in t
U
Permitted fifth wheel vertical load in t
t
Ton = 1000 kg
The permitted load data for products from SAF-HOLLAND are given in the
engraved product information Page 4 or can be found in the applicable
type approvals or on our home page www.safholland.com. They apply to
the operation on sealed, tarred roads and road conditions that are
customary in West Europe. In the case of operational conditions which
KP-0007
Fig. 4
· D-value calculation formula
5 Installation
18
XL-KP11695BM-en-DE Rev. A · 02.2015 · Errors and changes excluded · © SAF–HOLLAND
en
Summary of Contents for 50S15
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