Background of invention

The invention relates to a coupling device according to the preamble of claim 1, which is used for coupling containers to each other, and particularly for coupling containers used in cargo ships to each other. In addition to sea transport, containers are used for land transport.

Conventionally when aboard ships, stacks formed by containers are able to tilt sideways, depending on the degree of the list of the ship. This means that at least two corners i.e. those of one or the other side of the container are under pressure induced by the mass of containers above them.

On the other hand, when lifting containers, they are lifted such that all four corners are lifted up at the same time. For this reason, it is possible to distinguish clearly when the coupling devices of the containers have to be brought to the locking mode or the unlocking mode. In known arrangements, vertical force, i.e. lifting force, is converted in the coupling device into lateral (horizontal) force which compels the container being lifted, the upper and the lower one, to move sideways in relation to each other.

Prior art

Various arrangements are known from prior art for coupling containers to each other. Such arrangements are known in which containers are coupled to each other by coupling devices which operate totally manually i.e., when using them, the coupling occurs in both the locking stage and the unlocking stage totally by hand. Also semi-automatic and fully-automatic coupling arrangements are known. This now described coupling device relates to such a coupling device which operates fully- automatically.

From specification EP1810938 is known a coupling arrangement for coupling containers, which arrangement describes a fully-automatic coupling piece, which coupling piece includes a cam-like part for receiving the weight of the container being lifted and one rotatable locking piece for enabling the locking mode and the unlocking mode. The locking piece is arranged movable on the opposite side of the camlike part.

A fully-automatically operating coupling arrangement is described in specification WO2006/137759 Al. The coupling device according to the specification depicts an arrangement for coupling containers to each other, which coupling device includes a body in which is connected a locking part which operates by rotating around a vertical shaft for locking and unlocking. The locking part thus includes asymmetrical guide surfaces by means of which the locking mode and the unlocking mode are provided. From specification WO2005054086 is known a coupling device for coupling containers, which is particularly used for coupling containers used in ships to each other, and which coupling device includes a fastening piece formed on the upper part of its body part, by which piece the body part is fastenable in a corner piece of a container corner by rotating the body part around its vertical shaft, whereby the fastening piece is fastened in the corner piece of the container, and a planar coupling plate is further formed in the body part between its upper part and lower part, and the body part also includes a cam part which controls the motion of the body part, which can receive substantially vertical forces between the containers. The body part is also fitted with a first rotatable lever-like locking part for preventing and/or releasing the motion of the body part, and the body part further includes a second rotatable lever-like locking part for enabling or preventing the lateral motion of the body part and for receiving substantially vertical forces between the containers.

Arrangements according to prior art include some disadvantages. The arrangements according to known prior art operate asymmetrically i .e., in other words, only the couplings (lockings) of one side operate in lower containers. Because of this, their operation can be unreliable and even cause dangerous situations, because the locking of the coupling devices can fail due to forces induced by the asymmetric lockings. This is possible particularly when there are unwanted deviations from set dimensional tolerances in the containers. Already with safe loads, the lockings induce permanent changes in the corner pieces of the containers due to one-sided load distribution, and this is extremely disadvantageous. The coupling arrangements are part of a larger entity which includes also other parts (such as locking bars etc.), and these parts have to receive great loads which are generated when the containers are coupled in the ship and when the ship moves, and the parts have to be able to lock the containers fast in each other and in the ship. If displacements in the coupling arrangements, i.e. the displacement of coupling arrangements when they are being fitted in the corner pieces of the containers, grow too great, there is then a risk of other than the coupling pieces, such as locking bars etc., receiving too great forces and the system overloading.

The object of this invention is thus to provide a novel kind of a coupling device for coupling containers to each other, by which coupling arrangement, it is possible to eliminate or minimise the disadvantages of known arrangements and to achieve a well and reliably operating coupling device arrangement.

Brief description of invention

The coupling device according to the invention is characterised by what is stated in the characterising part of claim 1. The arrangement according to the invention is further characterised by what is stated in claims 2-10. The now described arrangement according to the invention provides some considerable advantages when compared to known arrangements.

By means of this now described invention, a novel kind of a coupling device is provided for coupling containers to each other, by which problems of known arrangements can be eliminated, and by which is indeed achieved a coupling device which is easy to use and reliable in use. The coupling device can couple the containers to each other such that they cannot unlock from each other unintentionally and it operates effectively for receiving substantially vertical forces between the containers (and also forces in other directions) and, the containers being coupled, the coupling device well endures stresses applied to it. Furthermore, the arrangement according to the invention is relatively simple and inexpensive to manufacture.

Brief description of figures

The invention will next be described in more detail by means of examples with reference to drawings 1-7 in which

Figs, la, lb and lc show a coupling device according to the invention.

Figs. 2a-2c show the coupling of two containers to each other by the coupling device according to the invention. Figs. 3a-3c show the unlocking of the coupling between two containers.

Fig. 4 shows a situation of two containers being coupled to each other and a rotational motion between them i .e. the rotation of one container around a vertical shaft in a lifting situation.

Fig. 5 shows a corner piece in container corners. Fig. 6 shows vertical forces which occur in the coupling of the container.

Fig. 7 shows the coupling device in a situation of a corner of one container trying to lift upwards as the container stack is tilting.

Detailed description of invention According to Figs, la, lb and lc, a coupling device according to the invention includes a fastening piece 2 in its body part 48, formed in the upper part of the body part, by which the body part is fastenable in a corner piece 26 (see Figs. 2a, 6) in the corner of a container 40 by rotating the body part 48 around its vertical shaft, whereby the fastening piece fastens in the corner piece of the container such that horizontal surfaces 10, 11 in the body part receive vertical forces and vertical surfaces 4, 12 in the body part receive horizontal forces. In the body part is formed between its upper part and lower part a planar coupling plate 3 which coupling plate sets between containers 40, 41 being lifted (according to Fig. 2c) and receives forces between the containers, mostly the weight of the upper container 40, and the coupling plate further receives and transfers friction forces which are generated by the weight of the containers when the containers 40, 41 set on top of each other try to move horizontally in relation to each other.

The body part employs an (elongated) cam part 6 for controlling the motion of the body part, and the body part is fitted with a first rotatable lever-like locking part 5 for preventing and/or releasing the motion of the body part.

In the body part is also formed a second rotatable lever-like locking part 8 for enabling the lateral motion of the body part. For receiving vertical forces, in the second lever-like locking part 8 is formed a projection 34, and the second locking part is directly or indirectly in contact with the first lever-like locking part 5 such that, as the first lever-like locking part rotates, the second lever-like locking part is also able to rotate for enabling the locking mode and the unlocking mode (shown in Figs. 2a-2c). The second lever-like locking part is fitted with a spring-like piece (not shown in the figures when being fitted within the body part) which is arranged to push (or pull) the second locking part within (or out of) the body part, into a slot 20 in the body part. The spring-like piece can also be connected to the first locking part. The second locking part thus presses the first locking part outwards of the body part, it being directly or indirectly in contact with the first locking part. When the second locking part is not loaded in any way, it is in the position shown by Fig. lc i.e. it includes surfaces which protrude from the cam part 6. The first locking part is pressable within the cam part partially or totally and it is then loaded by pressing a surface 14, whereby it rotates around a shaft 25, moving within the cam part 6, into the slot 20. The second locking part 8 includes the projection 34 which projection has a surface 42 which prevents the vertical motion, such as shown e.g. in Fig. 7. In Fig. lb, reference numbers 31, 32, 33, 35 show bevels in the coupling device.

Figs. 2a-2c show the coupling of two containers 40, 41 to each other by the coupling device 1 according to the invention, in which situation of Fig. 2a, the coupling device is fastened in the corner piece 26 of the upper container 40 by means of the fastening piece 2 in the body part such that the horizontal and vertical surfaces 4, 10, 11 and 12 (shown in Fig. 1) of the fastening piece 2 are in contact with mating surfaces 21, 22, 23 and 24 of the corner piece, keeping the coupling device in place in the corner piece, whereby the coupling device cannot move in the corner piece in the horizontal or vertical direction. According to the figure, a lower corner piece 27 stays in place and the upper corner piece

26 moves downwards, in which upper corner piece the coupling device 1 is fastened.

When the upper container where the coupling device is fastened has been lowered downwards (according to Fig. 2a), a contact is created between surfaces 36, 37 of the lower corner piece 27 and surfaces 42, 18 of the first locking part 5 and the second locking part 8.

According to Fig. 2b, when the upper container 40 is further lowered, a contact is created as the second locking part 8 contacts the corner piece

27 such that a contact takes place as a surface 39 of the corner of the lower corner piece 27 contacts a (curved) surface 17 Of a projection 13 of the second locking part. The first locking part equivalently contacts a surface 38 of the second (opposite) corner of the corner piece. Furthermore, the second locking part 8 'presses' the first locking part 5 (is coupled to it), because surfaces 15, 16 of the first and the second locking part are in contact with each other. Additionally when lowering the upper corner piece 26, the second locking part 8 rotates such that it rotates counter clockwise and equivalently the first locking part 5 rotates clockwise. Then, the upper corner piece is able to move to the right. Equivalently, the second projection-like protrusion 13 in the second locking part 8 contacts by its surface 17 ^' the surface 39 of the corner piece and controls the lateral motion (i.e. pushes the first locking part in the locking position).

According to Fig. 2c, when the upper container is lowered so much that the upper container rests on top of the lower container, and its weight presses the lower container via the coupling plate 3 and friction forces are induced between them, because the lower surface 40 of the coupling plate 3 contacts a surface 44 of the corner piece 27 of the lower container.

According to the figure, the corner pieces 26, 27 are thus in incidence. Then, the first and the second locking part are rotated such into their extreme positions that the second locking part 8 is within the body part and contacts by the surface 17 ^' only the surface 39, and the second locking part is again equivalently rotated such that it is in contact by its surface with the surface 37 of the corner piece.

Figs. 3a-3c show the unlocking of the coupling between two containers when the upper container is lifted with a lifter or some other lifting device.

According to Fig. 3a, as the upper container 40 is on top of the lower container 41, its weight induces friction force between the containers such that the coupling plate 3 presses the lower corner piece 27 and friction force is thus generated between them. The friction prevents the motion of the containers 40, 41 in relation to each other. According to the figure, the corner pieces 26, 27 are in incidence. The first and the second locking part are rotated such that the second locking part 8 is within the body part and contacts by the surface 17 only a vertical surface 45 of the corner piece, and the second locking part is again equivalently rotated such that it is in contact by its surface 19 with the surface 37 of the corner piece.

According to Fig. 3b, when the lifting of the upper container is started, the friction force prevailing between the containers exits, and a horizontal motion induced by the coupling device 1 (coupling devices) between the containers is generated, and the surface 18 of the first locking part and the surface 42 of the second locking part control the horizontal motion. The first and the second locking part 5, 8 are then able to rotate controllably (freely) when being in contact with the surfaces of the corner piece 27.

According to Fig. 3c, when the upper container is further lifted, the horizontal motion still continues until the surface 42 of the second locking part no longer contacts the corner piece 27.

According to Fig. 3c, the coupling device 1 can be lifted up from the lower corner piece 27, when the first locking part 5 and the cam 34 do not prevent the vertical motion. Then, the first locking part 5 is totally or almost totally rotated within, into the slot 20 shown in Fig. 1.

Fig. 4 shows a situation of two containers 40, 41 being coupled to each other, whereby the corners (corner pieces 26, 27) of the containers are in incidence. The upper container 40 is fastened from each corner by means of the coupling device (not shown in Fig. 4) to the lower container 41 from the corner pieces in the containers. The figure shows a rotational direction i.e. the direction in which the upper container is able to rotate when the lifting of the upper container is started. Then when lifting the upper container, friction forces between the containers induced by the weight of the upper container when being on top of the lower container exit, and the coupling devices are further able to unlock as shown in Figs. 3a-3c, at the same time a small rotational motion, i.e. a motion occurring around the vertical shaft of the containers, is generated between the containers. The coupling devices set at one end of the container are, in a situation in which the lifting of the upper container is started, able to move in the opposite direction than the ones set at the other end, and this enables the operation of the coupling device.

Fig. 5 shows a corner piece in container corners. According to the figure, the corner piece is a rectangular piece and a coupling opening 28 is formed in it on its above surface 44. The sides of the corner piece further include openings 29, 30 for lifting with a lifting hook or some other and for fastening support means etc.

According to Fig. 6, when the containers are coupled to each other in the corner pieces 26, 27 by the coupling devices 1, the containers coupled to each other tilting on the left, pressing (shown with an arrow) is created in a left corner 47 of the lower container which is induced by the weight of the upper container 40, and this pressing force further presses the left side of the lower container 41, its corner 47, inducing friction forces between the corner pieces of the container and the coupling plate, whereby the horizontal motion is prevented. The horizontal motion being prevented, the vertical motion is also prevented by means of the coupling device. Equivalently, in a corner 46 on the right side is generated pulling force which tries to pull the corner 46 separate from the equivalent corner of the lower container. The coupling devices 1 fitted in the right corner of the containers thus fall under tensile stress when the containers coupled to each other tilt to the left.

Between the containers, horizontal forces are also generated when the containers are tilting as the upper container 40 tries to move (slide) to the left, it being on top of the lower container 41.

Fig. 7 shows the operation of the coupling device (in a situation according to Fig. 6) in which the corner 46 tries to lift upwards as the container stack is tilting (in the corner 47 the weight of the upper container induces friction force between the containers). When the upper container 40 is on top of the lower container 41, and then its weight induces friction force between the containers such that the coupling plate 3 presses the lower corner piece 27 and, thus, friction force is generated between them. The friction prevents the horizontal motion of the containers 40, 41 in relation to each other and, at the same time, the corner pieces 26, 27 are not able to move in relation to each other horizontally. When the corner piece 26 of the upper container in the corner 46 tries to lift upwards, the vertical motion between the corner pieces is prevented by means of the first locking part 5 and the second locking part 8, because the surface 18 of the first locking part 5 contacts the surface 38 of the corner piece and the surface 42 of the projection 34 of the second locking part 8 contacts the lower surface 36 of the corner piece, due to which the coupling device 1 cannot lift upwards from the second, i.e. lower, corner piece because, said surfaces contacting each other, the motion upwards is prevented. It is well known by those skilled in the art that the different embodiments of the invention are not solely limited to the examples described above, and thus they can vary within the scope of the appended claims.