Tractor vehicle provided with a fifth-wheel plate

A tractor vehicle provided with a fifth-wheel plate (4) supported by a beam (3) mounted on the chassis of the vehicle vertically pivotably in the longitudinal direction of the vehicle on two fulcrums (5) spaced-apart in the transverse direction of the vehicle. The fulcrums of the beam are selectively together or separately displaceable in the longitudinal direction of said vehicle. In this way the fifth-wheel plate is displaceable not only in the longitudinal direction (A) of the chassis by displacing both fulcrums simultaneously but also in the transverse direction (B) of the chassis by displacing only one fulcrum (FIG. 4).

The present invention relates to a tractor vehicle provided with a 
fifth-wheel plate, comprising a chassis, a beam mounted on said chassis 
vertically pivotably on two fulcrums spaced-apart in the transverse 
direction of said vehicle, and a fifth-wheel plate supported by said beam. 
Such a tractor vehicle is used, for example, in harbours for transporting 
semitrailers, ferry cars and similar vehicles. 
It is previously known to mount a fifth-wheel plate on horizontal slide 
bars mounted in the upper end of a beam so that the fifth-wheel plate, by 
means of power-driven displacing means, is displaceable in the 
longitudinal direction of the vehicle closer to the centre of gravity of 
the vehicle. The aim is to displace in this way the point of support 
between the fifth-wheel plate and a load connected to the vehicle to a 
more advantageous position as far as the stability of the vehicle is 
concerned and at the same time to shorten the total length of the vehicle 
assembly. The beam is in this case mounted at its lower end on the chassis 
by means of two pivot shafts which are fixed in relation to the chassis. 
However, a drawback in the fifth-wheel plate construction described above 
is that the displacing means to be arranged in the upper end of the beam 
require a certain space under the fifth-wheel plate, which necessitates 
the arrangement of a corresponding free space on the chassis in order to 
be able to turn down the beam and the fifth-wheel plate to a sufficient 
extent. In addition, pressure-medium tubes required by the displacing 
means must be provided underneath the fifth-wheel plate. 
An object of the present invention is to provide a tractor vehicle provided 
with a fifth-wheel plate which eliminates the above-mentioned drawbacks 
and permits the displacement of the fifth-wheel plate in relation to the 
chassis in a more versatile manner. This object is achieved by means of a 
tractor vehicle according to the invention, which is characterized in that 
said fulcrums of said beam are jointly and separately displaceable in the 
longitudinal direction of said vehicle. 
The invention is based on the idea that, by making the beam displaceable in 
relation to the chassis instead of making the fifth-wheel plate 
displaceable in relation to the beam, not only a possibility of 
longitudinally displacing the fifth-wheel plate is obtained but also a 
possibility of transversally displacing the fifth-wheel plate. At the 
lower end of the beam, considerably more space is available to mount on 
the chassis the most suitable means for the longitudinal displacement of 
the beam, and these means require no space under the fifth-wheel plate. 
Similarly, no pressure medium tubes need be provided along the beam. 
By displacing both fulcrums of the beam simultaneously in the same 
direction, the fifth-wheel plate can be displaced in the longitudinal 
direction of the chassis, while displacement of only one of the fulcrums 
of the beam will displace the fifth-wheel plate in the transverse 
direction of the chassis. Owing to such a possibility of transverse 
displacement, the load can be laterally positioned more precisely in 
place, for example, when loading a ship in which connection the disposal 
of space is important. Similarly, it is possible to displace to load 
laterally, which facilitates backing with a vehicle because the driver has 
an unobstructed view backwards past the load. In addition, the stability 
of an articulated vehicle can be improved by means of lateral displacement 
of the load, for example, when driving in a curve, on ship's ramps, etc.

The tractor vehicle shown in the drawings comprises a chassis 1 which is 
movable on wheels. A fifth-wheel means 2 is mounted on the rear part of 
the chassis. 
The fifth-wheel means comprises a lifting beam 3 on the upper end of which 
is articulately mounted a fifth-wheel plate 4 known per se. The beam is 
bifurcate in its lower part, each leg being mounted for support on the 
chassis in two fulcrums 5 spaced-apart in the transverse direction A of 
the chassis. Each fulcrum comprises a lever 6 which in its lower end is 
mounted on a transverse pivot pin 7 supported by the chassis and which in 
its upper end is likewise provided with a transverse pivot pin 8 on which 
the leg of the beam is pivotably journalled. The pivot pin 8 of the lever 
is connected with a hydraulic cylinder 9 which, in turn, is mounted on the 
chassis. 
The fulcrum 5 of the second leg of the beam comprises the same parts, 
whereby the pivot pins 7 are located coaxially and the pivot pins 8 are 
also located coaxially in the embodiments shown in FIGS. 2 and 3. By 
operating the hydraulic cylinders the lever 6 can be pivoted in a vertical 
plane in the longitudinal direction B of the chassis between a retracted 
position shown in FIG. 2 and a protruding position shown in FIG. 3. For 
pivoting the beam in the vertical plane, a lifting cylinder 10 known per 
se is mounted between the beam and the chassis. 
The tractor vehicle is backed in front of a semitrailer, ferry car or 
similar vehicle to be transported, while the beam 3 is lowered down into 
the position shown by broken lines in FIG. 1. When the fifth-wheel plate 
has been connected to the load to be hauled, the beam is by means of the 
lifting cylinder 10 raised into the position shown by solid lines in FIG. 
1. Thereafter, the levers 6 are pivoted into the protruding positions 
shown in FIG. 3 so as to displace the fifth-wheel plate forwards to the 
raised position indicated by broken lines. This improves the stability of 
the vehicle because the support point between the plate and the load will 
in this way be displaced closer to the centre of gravity of the vehicle. 
It will be noted that plenty of space is available at the lower end of the 
beam for the displacing means required for displacing the fulcrums of the 
beam. 
In order to facilitate the backing of the vehicle or in order to pack the 
load more tightly in the cargo space of a ship etc. or in order to improve 
the stability of the vehicle, the lever 6 or one fulcrum of the beam is 
turned into the retracted position by means of the corresponding hydraulic 
cylinder, whereby the fifth-wheel plate will be displaced in the 
transverse direction of the chassis into the position indicated by solid 
lines in FIG. 4. The mounting of the beam legs on the pivot shafts 8 has 
naturally been carried out so as to permit such a small angular movement 
of the beam in relation to the pivot pins. 
The drawings and the related specification are only intended to illustrate 
the idea of the invention. In its details the tractor vehicle may vary 
considerably within the scope of the claims. This concerns especially the 
mounting of the beam on the chassis, which may be carried into effect in a 
number of different ways, for example, by means of slides, which are 
longitudinally displaceably mounted on the chassis and are displaced by 
means of hydraulic cylinders and which replace the levers described above. 
Alternatively, the legs of the beam may be journalled on a common pivot 
pin which in its ends is supported by bearings which are displaceable 
together or separately longitudinally of the vehicle. Instead of hydraulic 
cylinders, various mechanical displacing means may be contemplated.