WO2012045812A1

WO2012045812A1 - Stabilising leg

Info

Publication number: WO2012045812A1
Application number: PCT/EP2011/067462
Authority: WO
Inventors: Bengt-Olof Hammar
Original assignee: Bengt-Olof Hammar
Priority date: 2010-10-06
Filing date: 2011-10-06
Publication date: 2012-04-12

Abstract

The present application relates to a support structure for a trailer provided with a cargo crane, said support structure having a first leg connected to said trailer, a pivotable leg, a pivot between said first leg and said pivotable leg, and a piston for pivoting said pivotable leg relative to said first leg. Said pivotable leg has a first shank and a second shank in fixed essentially perpendicular relationship to each other, wherein said first shank is pivotably connected to said pivot and a first end of said piston is arranged to said first leg and a second end of said piston is arranged to the pivotable leg such that said first shank gives rise to a lever for said piston in relation to said pivot.

Description

STABILISING LEG

Technical field

The present invention relates to a support structure for a trailer provided with a cargo crane. Said support structure has a first leg connected to said trailer, a pivotable leg, a pivot between said first leg and said pivotable leg, and a piston for pivoting said pivotable leg relative to said first leg. Said pivotable leg has a first shank and a second shank in fixed essentially perpendicular relationship to each other, wherein said first shank is pivotably connected to said pivot and a first end of said piston is arranged to said first leg and a second end of said piston is arranged to the pivotable leg.

Background of the invention

It is common to transport freight containers at least a part of a distance on roads using trucks having trailers specifically designed for this purpose. The containers are also called ISO containers or intermodal containers. The term "trailer" in and throughout this application is meant either one of full trailer, semi-trailer or on the truck itself. These trailers usually have hydrauli- cally powered lifting cranes to load and unload the containers from the ground, from another trailer or else. These are often referred to as "sidelift- ers". In order to stabilise the trailer and container during a loading and unload- ing situation the trailer is also provided with hydraulically powered, foldable stabilising legs, which may be stored in a folded position in front of and behind the container when loaded onto the trailer. These stabilising legs are when unfolded located on the same side of the trailer as the crane is. Similarly are the crane arms stored in front of and behind the container on the trailer when not in use. Usually a trailer may be loaded with two 20 ft long containers or with a 40 ft long container. In order to achieve this at least one of the support legs and the crane arms are movable along the length of the trailer.

Certain types of stabilising legs are positioned on the ground such that a second trailer may be positioned adjacent the first trailer to receive a con- tainer from the first one without touching the second trailer with the stabilising leg. In this position the stabilising leg also stands clear of the second trailer.

Other types of stabilising legs exist. Such legs may be a type which in a folded position on the trailer is stored swung backwards such that the foot of the leg is pointing slightly upwards or at least located horizontally. When using the leg, it is tilted around a hinge on the same side as the container is to be lifted resulting in a leg located inclined at an angle approx. 45 deg. from the ground towards the trailer. Such a stabilising leg intervenes with the area in which another trailer may be located and may thus not always be used.

The present invention relates in general to the first type of stabilising leg. A trailer according to the invention may be either a semi-trailer or a full trailer. The cargo transported by the trailers and handled by the cranes may naturally be other than of freight container type.

There is a need to improve safety when handling these stabilising legs. For instance there have been accidents when folding the stabilising leg in which the operator has been clamped between the leg parts. There is also a need to improve the general design such that manoeuvrability is maintained or even improved while the stabilising leg is better adapted for its purpose. Summary of the invention

The object of the present invention is to at least to a certain extent overcome the above mentioned disadvantages. These and other objectives will become apparent by the following description.

According to one aspect of the invention a support structure for a trailer provided with a cargo crane, said support structure having a first leg connected to said trailer, a pivotable leg, a pivot between said first leg and said pivotable leg, and a piston for pivoting said pivotable leg relative to said first leg, said pivotable leg having a first shank and a second shank in fixed essentially perpendicular relationship to each other, wherein said first shank is pivo- tably connected to said pivot and a first end of said piston is arranged to said first leg and a second end of said piston is arranged to the pivotable leg such that said first shank gives rise to a lever for said piston in relation to said pivot. One major advantage is that the piston is located such that its lever is close to or at its maximum resulting in an optimal utilisation of the piston force during advancing and folding of the support structure. Especially when the pivotable leg is close to its folded position this is advantageous since the weight of the pivotable leg otherwise might have resulted in a "guillotine effect", i.e. that the folding might be uncontrollable and too quick, resulting in a dangerous situation for the user or any other person standing within the range of the support structure. Another advantage is that the height of the support structure when positioned either on the ground next to the trailer, or on an- other adjacent trailer or train may be better controlled and opens for a wider range of usage of the cargo cranes. The support structure may also be used when the pivotable leg is still folded, but the first leg is advanced. In this position the second shank of the pivotable leg may be located on top of an adjacent trailer for relocation of a container from one trailer to the other. The loca- tion of the piston and the resulting lever achieves a strong support structure and the position of the second shank on top of the other trailer may thus be chosen freely and not as in prior art legs in one single position close to the first shank. It also achieves a wide lifting range away from the trailer although a prior art cargo crane may be used. The cargo cranes may also be used to stack two containers on top of each other. The support structure becomes stronger or at least as strong in all positions in comparison to prior art legs. The support structure may also be swung freely in relation to the cargo cranes in its whole range of motion and is located next to the cranes without intervening with one another. Both the support structure and the cargo cranes may thus be designed to fulfil their own purposes better.

According to another aspect of the invention said lever has a maximum length, and in a folded position of the support structure has a length which is within a range of 75 - 100 % of said maximum length, preferably within a range of 85 - 100 %, and more preferably within a range of 95 - 100 %.

According to another aspect of the invention said lever has a maximum length of at least 500 mm, preferably of at least 600 mm, and more preferably of at least 700 mm. According to another aspect of the invention said second end is arranged to said pivotable leg between said first shank and said second shank.

According to another aspect of the invention said first shank is connected to said second shank directly.

According to another aspect of the invention said second end is arranged to the pivotable leg essentially in an intersection between said first shank and said second shank.

According to another aspect of the invention said first shank has a length of at least approx. 500 mm.

According to another aspect of the invention said first leg has an external profile which widens seen in a direction away from said pivot.

According to another aspect of the invention said first shank has an external profile which widens as seen in a direction away from said pivot.

According to another aspect of the said piston is located outside said first leg. Hereby said first leg me be designed based upon its own conditions without influence from other properties. A first leg according to prior art is designed such that the piston is located within the first leg and the length of the lever is consequently limited to the width of the leg.

According to another aspect of the invention said first leg is pivotably connected to said trailer via a second pivot located on a cross beam arranged to said trailer.

According to another aspect of the said cross beam is arranged to a longitudinal girder on said trailer, which longitudinal girder forms an under- body for said trailer.

According to another aspect of the invention a second piston is arranged between said first leg and said cross beam for advancing of said support structure.

According to another aspect of the invention a first end of said second piston is pivotably arranged to said first leg such that a second lever is achieved for said second piston in relation to said second pivot.

According to another aspect of the invention said second pivot is located at a first end of said cross beam, and a second end of said second piston is arranged to a second end of said cross beam. Brief description of the drawings

The invention will now be described with the aid of the accompanying drawings, in which

Fig. 1 a shows in perspective view a semi-trailer having a support arrangement according to the invention,

Fig. 1 b shows the invention as in Fig. 1 a loaded with a freight container,

Fig. 2a shows in a view from behind the semi-trailer with support ar- rangement from Fig. 1 a in which the support arrangement is slightly launched, Fig. 2b shows the invention as in Fig. 2a in which the support arrangement is further launched,

Fig. 2c shows the invention as in Fig. 2b in which the support arrangement is further launched,

Fig. 2d shows the invention as in Fig. 2a-c in which the support arrangement is fully launched,

Fig. 3 shows in perspective view the invention as in Fig. 2d during lifting of a freight container,

Fig. 4 shows schematically shows a movement of a piston of the inven- tion, and

Fig. 5 shows in perspective view a semi-trailer having a support arrangement according to the invention during unloading of a freight container onto a second semi-trailer positioned adjacent the first one. Detailed description of a preferred embodiment of the invention

In the following a presently preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. According to Fig. 1 a semi-trailer 1 is carrying two cargo cranes 3a, 3b (a fore one and an aft one) and two stabilising legs 2a, 2b (a fore one and an aft one) according to the present invention. There is generally no difference between the fore and aft one except for the location on the trailer 1 . However, it may be that the fore and aft stabilising legs 2a, 2b are not similar. In one embodiment one cargo crane is of the kind presented in this application, and the other is of another type. Also, one stabilising leg may be of a kind described in this application, and the other of another kind. The two stabilising legs 2a, 2b are located on the outside of the two cargo cranes 3a, 3b. Both the stabilising legs 2a, 2b and the cargo cranes 3a, 3b are separately slidable along the extension of the trailer 1 . A stabilising leg 2a, 2b is moveable along the trailer 1 and swingable irrespective of the location of or design of the cargo crane 3a, 3b. A semi-trailer 1 equipped this way is often referred to as a "side- lifter" 1 . The semi-trailer 1 may as well be a full trailer 1 or a truck 1 without altering anything essential to the invention or without leaving the intention of the claim scope. The two stabilising legs 2a, 2b are one embodiment of a support arrangement according to the claims. The position of the stabilising leg 2 on the trailer 1 in Fig. 1 a is a so called folded position.

In Fig. 1 b the trailer 1 is loaded with a 20 ft freight container 4 between the stabilising legs 2a, 2b and the cargo cranes 3a, 3b. The trailer 1 and the stabilising legs 2a, 2b may also be used to lift a 40 ft freight container 4, thus utilising more of the length of the trailer 1 .

Fig. 2a shows a trailer 1 from behind having a cargo crane 3 folded to its maximum. The stabilising leg 2 is partially advanced. The stabilising leg 2 comprises a first leg 10 and a pivotable leg 1 1. The pivotable leg is divided into a first shank 1 1 a and a second shank 1 1 b. The first shank 1 1 a is shorter than the second shank 1 1 b and they form an almost right angle (90 °) to one another. The outer profile of the corner may be pointed. The corner formed this way is rigid. The second shank 1 1 b is at its end away from the first shank 1 1 a provided with a foot support 16 for load bearing on the ground.

The pivotable leg 1 1 is pivotably connected to the first leg 10 by a first pivot 22. The first leg 10 is pivotably connected to the trailer 1 by a second pivot 19. Two pistons 12, 13 actuate the movements of the stabilising leg 2. A first piston 13 actuates the pivotable leg 1 1 in relation to the first leg 10 and is connected to the stabilising leg 2 by two pivots 17, 18. One pivot 17 is located between the first and second shank 1 1 a, 1 1 b in the corner formed there between. The other pivot 18 is located at the end of the first leg 10 which is opposite to the first pivot 22. This pivot 18 is connected to a cross beam 14, which in turn is connected to the trailer 1 transversely to longitudinal axis of the trailer 1 via two longitudinal girders 15a, 15b. A second piston 12 actuates the first leg in relation to the trailer 1 and is pivotably connected to the first leg 10 by two pivots 20, 21 . One pivot 20 is located a short distance away from the second pivot 19 at one end of the second piston 12, and another pivot 21 is located at the end of the cross beam 14 opposite the end comprising the second pivot 19.

The outer dimensions of the stabilising leg 2 are such that they are generally smallest close to the first pivot 22 and generally widest away from said pivot. Between these extremes they widen continuously in a straight manner, creating a box-like rectangular and hollow steel structure.

When launching the stabilising leg 2, the first and second pistons 12, 13 may be actuated either simultaneously or one after the other. In Fig. 2a both pistons 12, 13 are slightly actuated. Another manner would consequently be to first actuate the second piston 12 such that the first leg 10 is actuated whilst the pivotable leg 1 1 remains in its folded position until - and if - it is later actuated. Fig. 5 shows a situation when the pivotable leg 1 1 still folded.

In Fig. 2b the stabilising leg 2 is lightly more launched than in Fig. 2a. Both the first and second piston 12, 13 are further actuated. In Fig. 2c the first and second pistons 12, 13 are even more launched unfolding the first leg 10 and the pivotable leg 1 1 . Finally, in Fig. 2d the stabilising leg 2 has been launched such that the foot support 16 has reached ground and the side lifter is ready to load or unload containers. This is shown in Fig. 3 in which a container 4 is underway of loading or unloading by the cargo cranes 3a, 3b. The container 4 is coupled to the container 4 by steel chains.

Fig. 4 schematically shows the movements of the first piston 13 and the pivot 17 in relation to the second pivot 22. Between the first piston 13 and the second pivot 22 is a lever H created having a right angle (90 °) to the first piston 13. The movement results in a circular C movement of the pivot 17 having the second pivot 22 at its centre. The maximum lever H_m is created when the first piston 13_m is located such that it forms a tangent to the circle C. In the figure four positions of the first piston (13i, 13₂, 13₃, 13₄) and the pivot (17-1 , 17₂, 17₃, 17₄) are illustrated in which for each position a lever is created (H-i, H₂, H₃, H₄). The positions correspond generally to the positions according to the present invention. It is clearly visible that when the pivotable leg 1 1 is fully folded the first piston 1 3i is positioned such that the lever Hi is very close to the maximum value of the lever H_m. In the present invention the maximum lever H_m is approximately more than 750 mm and the first shank 1 1 a of the pivotable leg 1 1 is approximately more than 500 mm. When fully folded the lever H becomes approximately 95 % of the maximum length of the lever H_m.

It should be noted that when the pivotable leg 1 1 and the whole stabilising leg 2 is in its generally most launched position, such as in Figs. 2d and 3, the lever H is at its generally minimum value. In this position the pivotable leg 1 1 is not subjected to high loads and therefore the lever H is enough to absorb the loading situation.

Fig. 5 shows a situation in which the stabilising leg 2 is launched and the trailer 1 is located adjacent a second trailer 1 onto which a freight container 4 is under way of transfer. The second trailer 1 is in this case a trailer 1 having the same height as the first trailer 1 . This is however not necessary thanks to the flexibility of the present invention and the second trailer 1 may be lower and the stabilising leg 2 may still function properly. It is noted from this figure that the second shank 1 1 b of the pivotable leg 1 1 may come in contact with the girders 15a, 15b of the second trailer 1 at any location along the second shank 1 1 b, from the pointed rigid corner to the foot support 16. This is possible due to the strength of the stabilising leg 2 thanks to the i.a. the location of the piston 13 and pivot 17 creating a lever between the piston 13 and the first pivot 22. The stabilising leg 2 may also reach further out in comparison to many prior art legs thanks to the design of the pointed corner.

Many ways of altering the present invention may be made without leaving the intention and the scope of the claims. Such alterations may be the length of the first shank 1 1 a which may be less than the stated length. The pivot 17 may be located somewhere along the first shank 1 1 a, i.e. closer to the first pivot 22. It is however advantageous that the lever H created is within a range of 75 - 100 % of its maximum value H_m, or preferably within 85 - 100 %. The movement of the stabilising leg 2 according to Fig. 4 is such that the stabilising leg 2 passes its maximum lever H_m at one point. This is not necessary, and the stabilising leg 2 still fulfils the feature to be located within the specified range of the maximum value of the lever H_m when folded. In the folded position of the pivotable leg 1 1 in relation to the first leg 10 the preferred embodiment exhibits an angle of less than 90 ° of its outer periphery (can be seen i.a. in Fig. 1 a).

If the first shank 1 1 a is made longer than in the shown figures, the first leg 10 may be made shorter and the total height in the folded position as seen in Fig. 1 a of the stabilising leg 2 may be made less. Furthermore, if doing so, the maximum length of the lever H_m may be made longer. If instead for some reason replacing the location of the pivot 17 along the first shank 1 1 a, a maximum lever H_m is still long and within the claims range even though the pivot 17 is not located in the corner between the first and second shanks 1 1 a, 1 1 b.

Claims

1 . A support structure for a trailer provided with a cargo crane, said support structure having a first leg connected to said trailer, a pivotable leg, a pivot between said first leg and said pivotable leg, and a piston for pivoting said pivotable leg relative to said first leg, said pivotable leg having a first shank and a second shank in fixed essentially perpendicular relationship to each other, wherein said first shank is pivotably connected to said pivot and a first end of said piston is arranged to said first leg and a second end of said piston is arranged to the pivotable leg such that said first shank gives rise to a lever for said piston in relation to said pivot.

2. A support structure according to claim 1 , wherein said lever has a maximum length, and in a folded position of the support structure has a length which is within a range of 75 - 100 % of said maximum length, pref- erably within a range of 85 - 100 %, and more preferably within a range of 95 - 100 %.

3. A support structure according to claim 2, wherein said lever has a maximum length of at least 500 mm, preferably of at least 600 mm, and more preferably of at least 700 mm.

4. A support structure according to any one of the preceding claims, wherein said second end is arranged to said pivotable leg between said first shank and said second shank.

5. A support structure according to any one of the preceding claims, wherein said first shank is connected to said second shank directly.

6. A support structure according to any one of the preceding claims, wherein said second end is arranged to the pivotable leg essentially in an intersection between said first shank and said second shank.

7. A support structure according to any one of the preceding claims, wherein said first shank has a length of at least approx. 500 mm.

8. A support structure according to any one of the preceding claims, wherein said first leg has an external profile which widens seen in a direction away from said pivot.

9. A support structure according to any one of the preceding claims, wherein said first shank has an external profile which widens as seen in a direction away from said pivot.

10. A support structure according to any one of the preceding claims, wherein said piston is located outside said first leg.

1 1 . A support structure according to any one of the preceding claims, wherein said first leg is pivotably connected to said trailer via a second pivot located on a cross beam arranged to said trailer.

12. A support structure according to claim 1 1 , wherein said cross beam is arranged to a longitudinal girder on said trailer, which longitudinal girder forms an underbody for said trailer.

13. A support structure according to any one of claims 1 1 to 12, wherein a second piston is arranged between said first leg and said cross beam for advancing of said support structure.

14. A support structure according to claim 13, wherein a first end of said second piston is pivotably arranged to said first leg such that a second lever is achieved for said second piston in relation to said second pivot.

15. A support structure according to claim 14, wherein said second pivot is located at a first end of said cross beam, and a second end of said second piston is arranged to a second end of said cross beam.

16. A trailer having a support structure according to any one of claims 1 to 15.