WO2005030570A1

WO2005030570A1 - A device for connecting a pusher tug to a barge

Info

Publication number: WO2005030570A1
Application number: PCT/FI2004/000570
Authority: WO
Inventors: Mika Laiho
Original assignee: ACOMARIN ENGINEERING Ltd Oy
Current assignee: ACOMARIN ENGINEERING Ltd Oy
Priority date: 2003-09-30
Filing date: 2004-09-30
Publication date: 2005-04-07
Anticipated expiration: 2006-03-30
Also published as: FI20031406A7; FI20031406L; FI20031406A0

Abstract

An apparatus (10) for connecting a pusher tub to a barge with connecting pin mechanisms (10), which connecting pin mechanisms are shaft mechanisms to be located in pairs on both sides of the pusher tub. Each shaft mechanism has a cylinder-like bush (12), inside of which bush there is an axially movable, cylinder-like connecting pin (11), which connecting pin can be hydraulically moved in axially opposite directions and can be locked into a slot in a side structure (30) of the barge. Connecting pins (11) locked in the slots in the side structure (30) of the barge act as shafts that rotate in the slots, around which shafts the pusher boat can pitch relative to the barge. The bush (12) attached in the connection mechanism (10) to the side structure (30) of the pusher tug is laterally suppported so that a protrusion (24) is formed at the outer end of the bush and that, when a lateral force is exerted on the end of the connecting pin (11), both the end of the connecting pin and the protrusion (24) at the end of the bush (11) around the connecting pin can bend.

Description

A DEVICE FOR CONNECTING A PUSHER TUG TO A BARGE

The present invention relates to an apparatus for connecting a pusher tug to a barge, which apparatus is a connecting pin mechanism to be located at a side of the pusher tug, - which connecting pin mechanisms are shaft mechanisms to be located in pairs on both sides of the pusher tug,

- both of which shaft mechanisms most preferably comprise a cylinder-like bush, inside of which bush there is an axially movable, cylinder-like connecting pin, which connecting pin can be hydraulically moved in axially opposite directions and locked in a slot in a side structure of the barge,

- which connecting pins locked in slots in the side structure of the barge act as shafts that rotate in the slots, around which shafts the pusher boat is able to pitch relative to the barge.

The use of a pusher tug for barge shipping has become widespread in maritime transportation. There are several known apparatuses for connecting a tug and a barge. The principal types of these apparatuses are so-called integrated tug and barge (ITB) and so- called articulated tug and barge (ATB) combinations. In an ITB combination, a pusher vessel is rigidly connected to a barge, i.e. the pusher vessel moves along with the barge due to the effect of waves. In such an apparatus, the pusher tug is driven for almost its entire length into a deep well formed in the stern portion of the barge, in which well there are no less than three connecting points at which the pusher boat and the barge are rigidly connected. In an ATB combination, a pusher boat is connected to a barge, for example, by means of cylinders located on both sides of the pusher boat so that the piston of a cylinder forms a cylinder-like pin that is connected to a matching slot in the barge. Because there is only one connecting pin on each side of the pusher boat, the pins act as articulated joints, about which the pusher boat can pitch relative to the barge.

In known articulated connecting mechanisms, however, there have been problems, for example, with the durability of the connecting pins. The cause of problems is often the very great momentary strain exerted on the connecting pin while it is being locked. The bending force exerted on the connecting pin may cause the pin to bend, flatten or even break. Also the clearance between the pusher boat and the barge is often too great, and very high torques are thus exerted on the connecting pins and in rough seas, such a joint may become damaged. The purpose of the present invention is to create a new connection mechanism between a pusher boat and a barge. It is characteristic for a connection pin mechanism according to the invention

- that the bush attached in the connection mechanism to the side structure of the pusher tug is laterally supported so that a protrusion is formed at the outer end of the bush,

- when a lateral force is exerted on the end of the connecting pin, both the end of the connecting pin and the protrusion at the end of the bush around the connecting pin can bend.

A perforated plate or a similar structure is arranged in the steel structures of the barge to be pushed, to which perforated plate the connecting pins may be locked in a slot or a hole at a desired height. The flexibility in movement required in the connecting pin at the moment of connection is created, for example, by means of a pressure accumulator.

According to one preferable embodiment of a connecting pin mechanism according to the invention, the external bush in the connecting pin mechanism is supported at a point at a certain distance from the outer end of the external bush, so that the outer end of the external bush can bend in the lateral direction.

What is accomplished by using a support solution of this kind is that the external bush provides the connecting pin with a more even support over a longer distance. In this way, no excessive peak of bending force is formed at any point of the connecting pin that could damage the pin.

In the following, the invention is described by means of examples referring to the accompanying drawings, in which

Figure 1 represents an embodiment of a connecting pin mechanism of a pusher vessel as a sectional view and in a situation where the connecting pin is at the starting phase of the connective motion.

Figure 2 is equivalent to Fig. 1 and represents the connecting pin mechanism in a situation where the connecting pin is at the midway position of the connective motion. Figure 3 is equivalent to Fig. 1 and represents the connecting pin mechanism in a situation where the connecting pin is extended, whereby the connecting pin mechanism is connected to the push barge.

Figure 4 represents another embodiment of the connecting pin mechanism as a schematic, sectional view in a situation where the connecting pin is extended. Figure 5 represents a schematic view of the connecting pin mechanism in Fig. 4 in a situation where a lateral force is exerted on the end of the connecting pin.

Fig. 1 represents a sectional view of a connecting pin mechanism 10 in a pusher vessel. The figure shows that the connecting pin mechanism 10 comprises an external bush 12, inside of which bush there is a connecting pin 11 axially movable in opposite directions. Between the external bush 12 and the connecting pin 11 there is a bearing bush 13. Inside the connecting pin 11 there is a hydraulic cylinder cavity 14, in which cavity there is a stationary or fixed piston 15. Furthermore, the connecting pin 11 is made lighter by providing a hollow space 16 inside the pin. Between the hydraulic cylinder cavity 14 and the hollow space 16 there is a partition 17.

In Fig. 1, the connecting pin 11 is in a retracted position, i.e. in a situation where the pusher tug is not connected to a barge. In Fig. 1 , connecting pin 11 in its extreme position on the left, so that the wall 17 of the connecting pin 11, i.e. the partition of the hydraulic cylinder cavity 14 located at the side of the hollow space 16, is pressed against the stationary or fixed piston 15. A protrusion 27 located at the end of a bar 19 attached to the connecting pin 11 acts as a position indicator so that in a position represented in Fig. 1 , it touches a limit switch 1 indicated by the reference number 28a.

The connecting pin 11 is moved outwards, i.e. to the right in Fig. 1, by conveying hydraulic fluid via a channel 20 passing via a piston rod 18 to the hydraulic cylinder cavity 14, between the stationary piston 15 and the partition 17.

In Fig. 2, the connecting pin 11 has proceeded to a midway position between its extreme positions. It can be seen in Fig. 2 that the protrusion 27 located at the end of a bar 19 attached to the connecting pin 11 is between the limit switches 1 and 2, i.e. between the limit switches indicated by the reference numbers 28a and 28b, without touching either of them.

In Fig. 3, the connecting pin 11 has proceeded to its extreme position on the right, i.e. it is extended as far out as its path of motion allows. In this position, the connecting pin mechanism 10 of a pusher tug is locked to a barge. The protrusion 27 located at the end of a bar 19 generates a corresponding position indication signal in that it is located at the limit switch 2, i.e. at the limit switch indicated with the reference number 28b. Fig. 3 shows that the outermost support point of the external bush 12 supported by the hull of the pusher tug is in a position 21. The outermost end of the external bush 12 thus remains a non-fixed protrusion, allowing it to slightly bend in a lateral direction due to the effect of any lateral forces. Similarly, the connecting pin 11 located inside the external bush 12 can also bend in a similar fashion, and therefore no excessive peak of bending force will be exerted on the connecting pin 11.

It is also an essential feature of the structure represented in Figures 1-3 that the end of the connecting pin 11 is narrower in the vicinity of the non-fixed end. Due to this, impacts exerted on the end portion of the connecting pin 11 while the pin is being locked will not damage the surface of the connecting pin 11 lying against the bearing bush 13. Thus also gaskets 22 at the reduced part of the connecting pin 11 remain undamaged.

Fig. 4 represents a schematically simplified view of another embodiment of the connecting pin mechanism 10 so that the connecting pin 11 is represented as a cylinder-like pin of equal thickness throughout its length. The bush 12 of the connecting pin mechanism is also cylinder-like in form and is represented in a simplified manner without any bearings or gaskets. Thus the figure more clearly demonstrates the support structure of the bush 12 and the behaviour of the support structure when the connecting pin 11 is laterally loaded, as represented in Fig. 5.

In the example represented in Fig. 4, the cylinder-like bush 12 has three, most preferably round flanges 23a, 23b and 23c, by which flanges the bush 12 is attached to the side structure 30 of a pusher tug. It is essential to the structure of the bush 12 that the outermost flange 23c is connected to the bush 12 at a certain distance from the outer end 24 of the bush 12. Thus a kind of protruding beam that supports the connecting pin 11 laterally, is formed at the outer end 24 of the bush 12.

Fig. 5 represents the connecting pin mechanism 10 of Fig. 4 in a situation where a lateral force F is exerted on the end of the connecting pin 11, which force is further exerted on the side structure 30 of the pusher tug via the bush 12. In Fig. 5, the force F is represented so that it is directed upwards from below. The oppositely directed, i.e. downwards from above in Fig. 5, supporting forces in the side structure 30 of the pusher tug are designated N1, N2 and N3.

Because of the form of the outermost flange 23c of the bush 12, this flange 23c will slightly yield due to effect of the lateral load of the bush 12 and bend to a curved shape, as seen in the cross section. In Fig. 5, this part of the flange 23c is shown above the bush 12. Thus also the protruding beam formed at the outer end 24 of the bush 12 and the connecting pin 11 therewithin similarly bend to a curved shape. Due to the deformation of the flange 23c of the bush 12, the portion of the flange 23c on the opposite side of the connecting pin 11 , i.e. the portion below the bush 12 in Fig. 5, is also deformed so that the portion which in the cross section is shown as curved is straightened.

The resilient structure of the connecting pin mechanism 10 represented in Fig. 5 results in the advantageous feature that the non-fixed ends forming the bush 12 and the protruding beam of the connecting pin 11 can bend until the support point 23b in the middle of the bush 12. Bending and deformation of the bush 12 and connecting pin 11 are represented by broken lines and, for the sake of clarity, in an exaggerated way in Fig. 5. In reality, the bending of the connecting pin 11 and bush 12 and deformations of the flange 23c are so minor that they cannot be seen as clearly as here. However, the resilience of the structure is a substantial advantage, which makes it possible to render the structure lighter, but nevertheless more durable. In known rigid solutions, the components have to be dimensioned to be substantially more massive for safety's sake, and even so, uncontrollable load peaks may break the structure.

It is obvious that, when the bush 12 and connecting pin 11 in a solution according to the invention bend for a considerable distance, i.e. from the protruding end 24 of the bush 12 to the support flange 23b in the middle, these will not be subjected to great shear forces exerted on a single point, as in known connecting pin mechanisms.

LIST OF REFERENCE NUMBERS

10 connecting pin mechanism

11 connecting pin 12 bush

13 bearing bush

14 hydraulic cylinder cavity

15 stationary piston

16 hollow space 17 partition

18 piston rod

19 bar

20 hydraulic fluid channel

21 support point 22 gasket of the reduction

23 flange of the bush 4 outermost end of the bush

27 protrusion 8 limit switch 0 side structure of the pusher tug

Claims

1. An apparatus (10) for connecting a pusher tug to a barge, which apparatus is a connecting pin mechanism to be located at a side of the pusher tug, s - which connecting pin mechanisms (10) are shaft mechanisms to be located in pairs on both sides of the pusher tug, - both of which shaft mechanisms most preferably comprise a cylinder-like bush (12), inside of which bush there is an axially movable, cylinder-like connecting pin (11), which connecting pin may be hydraulically moved in axially opposite directions and mayo be locked into a slot provided in the side structure (30) of the barge, - which connecting pins (11) locked in slots in the side structure (30) of the barge act as shafts that rotate in the slots, around which shafts the pusher vessel can pitch relative to the barge, c h a r a c t e r i s e d in that5 - the bush (12) attached in the connection mechanism (10) to the side structure (30) of the pusher tug is laterally supported so that a protrusion (24) is formed at the outer end of the bush, - and when a lateral force is exerted on the end of the connecting pin (1 1), both the end of the connecting pin and the protrusion (24) at the end of the bush (11) around the0 connecting pin can bend.

2. An apparatus (10) as claimed in claim 1, c h a r a c t e r i s e d in that - the bush (12) is supported on the side structure (30) of the pusher tug most preferably by no less than two lateral flanges (23),5 - the outermost lateral flange (23c) is supported on the protrusion (24) of the bush (12) and, in cross section, is most preferably curved in form so that it yields when the connecting pin (1 1) inside the bush bends due to the effect of a lateral load.

3. An apparatus (10) as claimed in any of the claims 1 or 2, c h a r a c t e r i s e d in that0 - the bush (12) is supported on the side structure (30) of the pusher tug by three lateral flanges (23), - between the two innermost lateral flanges (23a, 23b), the bush (12) is supported so as to render it mainly unbending, - between the midway lateral flange (23b) and the outermost lateral flange (23c), the5 bush (12) supported so that its head forms a resilient protrusion (24).

4. An apparatus (10) as claimed in any of the claims 1,2 or 3, characterised in that there is a gasket (22) at the end of the protrusion (24) of the bush (1 ), which gasket seals the clearance between the bush and the connecting pin (11).

5. An apparatus (10) as claimed in any of the claims 1-4, characterised in that the non-fixed end of the connecting pin (11) is narrower than the rest of the connecting pin.

6. An apparatus (10) as claimed in any of the claims 1-5, characterised in that the - the connecting pin (11) is hollow, - and the hollow space (16) inside the connecting pin (11) is divided by a partition (17) into two portions, one of which portions makes up a hydraulic cylinder cavity (14), which cavity axially moves the connecting pin.