Barge transport system

A barge transport system comprises one or several barges and at least one powered push vessel connectable to each of said barges for the transport thereof by pushing. The push vessel as well as each of the barges are provided with means for connecting the push vessel rigidly to a selected barge. The connecting means comprise connection members in the front portion of the push vessel as well as in its stern portion. The connection members in the stern portion of the push vessel are movable in the transverse direction of the push vessel into a mechanically positively locking connection position. The connection members and their counterparts are formed to exert a wedge effect on the connection, thereby minimizing any movement inducing connection clearance between the push vessel and the associated barge.

The invention relates to a barge transport system comprising one or several 
barges and at least one powered push vessel connectable to the barge or 
each of the barges for the transport thereof by pushing. The push vessel 
as well as each barge are provided with means for connecting the push 
vessel rigidly to any selected barge. 
Several different barge transport systems are known including a push vessel 
connectable to the stern portion of a number of barges. The connection 
between the push vessel and the barge gives rise to problems, firstly, 
because the floating level of the barge varies according to its load and 
secondly because open sea conditions require an extremely rigid connetion. 
Attempts to solve these problems have been made based on the use of 
different vertically adjustable connection devices. Both friction and 
mechanical clutch devices have been used to provide locking between the 
push vessel and the barge. Also longitudinal slide members and cable or 
chain attachments have also been used. Friction locking is generally not 
seaworthy. Connection means comprising long slide surfaces can neither be 
connected nor disconnected in rough water. Other known connection means 
are so complicated or bulky, that their use is impractical. 
The object of the invention is to solve the problem of connecting firmly a 
push vessel to a barge in a simple manner applicable and reliable also in 
open sea. 
According to the present invention there is provided a barge transport 
system comprising at least one barge and at least one powered push vessel 
connectable to said barge for propelling the barge by pushing, said push 
vessel and said barge being provided with means for connecting the push 
vessel to the barge, said connecting means comprising at least one 
connecting member in the front portion of the push vessel, at least two 
connecting members in the stern portion of the push vessel at opposite 
respective sides thereof, counterpart means in the barge for engagement by 
the connecting members, and means for moving the two connecting members in 
the stern portion of the push vessel into a mechanically positive locking 
relationship with the counterpart means, said connecting members and the 
counterpart means therefor being formed to exert a wedge effect when the 
two connecting members in the stern portion of the push vessel are so 
moved, thereby minimizing connection clearance between the push vessel and 
the barge. 
In an embodiment of the invention the push vessel is completely firmly 
connected to the barge by using connection means both in the front and in 
the stern portion of the push vessel, thereby forming a mechanically 
positively locking connection having a tightening wedge-effect and 
including adjustment possibilities to meet changes in the floating level 
of the barge. The expression "stern portion of the push vessel" means a 
portion of the push vessel being at a distance from the fore end of the 
push vessel of at least one half, preferably at least 3/4 of the length of 
the push vessel. The expression "mechanically positively locking" means 
mechanical locking by means of distinct support surfaces, not pure 
friction locking. 
In a preferred embodiment of the invention, the barge comprises a number of 
wedge-formed depressions or protrusions at different height levels, to 
which corresponding connection members of the push vessel can be connected 
for locking the push vessel firmly to the barge. The push vessel may have, 
at each connection position, a single connection protrusion and the barge 
corresponding connection depressions so arranged in vertical rows, that 
the push vessel can be connected to the barge at a desired level. It is 
preferred that the connection members in the stern portion of the push 
vessel are arranged to provide mechanical locking and a wedge effect also 
in the longitudinal direction of the push vessel and the barge. This can 
be arranged by providing the push vessel with transversely movable 
wedge-formed connection members having at their rear side a greater wedge 
angle than at their front side. 
Special care has to be taken regarding the strength and the operational 
reliability in open sea of the movable connection elements used in the 
push vessel. Connection elements movable by means of slide surfaces are 
usually not quite reliable in practice. It is preferred to use rotatably 
journalled connection members. Shaft bearings are easier to protect 
against moisture and dirt than slide surfaces. 
Since the realization of a connection system being infinitely variable in 
the vertical direction and at the same time mechanically very firm, is 
complicated, it is recommended to use a connection system having a 
plurality of fixed vertical connection positions arranged stepwise with a 
given pitch. In order to be able to always obtain, in spite of the pitch, 
a quick and reliable connection, it is practical to provide the push 
vessel with a trim arrangement, by means of which the draught and the trim 
of the push vessel can be adjusted as known per se. Thereby, the necessary 
fine adjustment of the vertical position of the push vessel relative to 
the barge is easy to carry out. 
Not only a strong connection between the push vessel and the barge is 
important, the connection must also be accomplished quickly and securely 
under difficult conditions. Since the connection is based on mechanical 
locking, and not on friction locking, the shape of the notch in the barge 
arranged to receive the push vessel can be made diverging over its total 
length, or at least substantially its total length in the backwards 
direction of the barge. Such a shape is considerably more difficult to use 
in known constructions having parallel slide surfaces in the barge. A 
diverging shape of the barge notch very essentially facilitates the 
connection of the push vessel to the barge. The hull of the push vessel is 
preferably shaped to correspond to the shape of the barge notch. Further, 
it is preferrd that the length of the notch is at least 80% of the length 
of the push vessel.

In the drawing, 1 refers to a push vessel and 2 to a barge. The bow of the 
push vessel has a wedge-formed connection protrusion 3 and the stern 
portion of the push vessel has wedge-formed connection members 4 at both 
sides. Protrusion 3 fits into a corresponding depressions 5 in the barge 
and connection member 4 into a corresponding depressions 6 in the barge. 
The water level is indicated by numeral 7. The position of the water level 
relative to the barge may vary considerably depending on the weight of the 
cargo carried by the barge. Push vessel 1 is connected to depressions 5 
and 6 at a suitable level by means of its connection members 3 and 4, 
respectively. If members 3 and 4 do not directly enter into a suitable 
depression, the connection can be assisted by using a trim system provided 
in the push vessel for adjusting its draught and trim position. Trim 
systems of this kind are well known. They usually comprise water tanks 
which are filled or emptied for changing the location of the center of 
gravity of the vessel and/or the weight of the vessel. 
An alternative method for the connection at the bow of the push vessel is 
shown in FIG. 3. In this embodiment, connection depressions 5a in barge 2 
are arranged in close relationship. There are correspondingly shaped 
connection members 3a in the bow of the push vessel. A greater number of 
connection members 3a provides a better connection grip. By means of the 
push vessel's own thrust force or any other longitudinal connection force 
system provided, connection protrusions 3a are forced to penetrate in a 
self-adjusting manner into a suitable connection depressions 5a, without 
any need of using a trim system of the push vessel. The principle shown in 
FIG. 3 can also be applied, but is less favourable with respect to the 
connection members in the stern portion of the push vessel and the 
corresponding connection surfaces of the barge. 
FIG. 4 shows how connection protrusion 3 in the bow of the push vessel 
provides support and a wedge effect also in the transverse direction of 
the vessel. Connection members 4 in the stern portion of the push vessel 
are movable in the tranverse direction, whereby they exert a wedge effect 
and lock push vessel 1 to barge 2 in a longitudinal direction as well. By 
this means an extremely firm connection between the push vessel and the 
barge is achieved and both units form together a rigid seaworthy unity. 
The connection of the push vessel to the barge is essentially facilitated 
by having a small clearance 8 between them where there are no connection 
members. Further, the push vessel and the corresponding notch in the stern 
end of the barge both have a backwards diverging form over the total 
length of the notch, as shown in FIG. 4. 
FIG. 4 also shows that the width of the notch is greater than the width of 
any portion of the push vessel that could contact the sides of the notch 
when the push vessel enters the notch. 
The swingable connection members 4 in the stern portion of push vessel 1 
are powered by means of hydraulic cylinders 9. FIG. 5 shows how members 4 
swing on a fixed shaft 10. Each connection member 4 is provided with two 
hydraulic power cylinders 9 to obtain a high connection force. When the 
push vessel is connected to the barge, a hydraulic pressure is 
continuously maintained in the power cylinders. Thereby continuously 
eliminating all connection clearances that could give rise to undesired 
movement between the push vessel and the barge. The retracted position of 
connection members 4 is shown in FIG. 5 by dashed lines. 
The push vessel 1 has a central plane about which its hull is substantially 
symmetrical, and the connection devices in the stern portion of push 
vessel 1 are symmetrically arranged at with respect to this central plane. 
When the connection members 4 are moved between their retracted positions 
and their projecting positions, they move substantially perpendicular to 
this plane. Since the extension downwards of the back portion of barge 2, 
as shown in FIG. 2, is relatively small at the position of connection 
openings 6, it is of advantage to have the corresponding connection 
members of the push vessel at a relatively high level. For this reason the 
connection head of each connection member 4 is at a higher level than the 
fixed shaft of the connection member. 
It is also possible to make the connection device of the stern portion of 
the push vessel vertically adjustable. Then there is no need for a 
plurality of connection depressions 6 in the barge. Only one at each side 
is sufficient. FIG. 6 shows schematically how such a vertically adjustable 
connection device could be constructed. Only the principle of the 
construction is shown, by no means its proper dimensioning. As in FIG. 5, 
swingable connection members 4 are journalled on a shaft 10 and their 
swinging motion is provided by hydraulic power cylinders 9. The shafts 10 
and the cylinders 9 are attached to the ends of support beams 11, the 
opposite ends of which are swingably journalled at a fixed point 12 in the 
push vessel. Second power cylinders 13 are connected to raise and lower 
the movable ends of support beams 11, whereby the connection level of 
connection members 4 is adjusted. 
The invention is not limited to the embodiments shown, but several 
modifications thereof are feasible within the scope of the attached claims 
.