Patent Description:
Container gantry cranes, also called STS (Ship to Shore) cranes, are known in the prior art. They consist of infrastructures for loading and unloading containers at transport terminals and usually comprise:.

Spreaders are devices by way of a grip frame, which usually hang from a carriage that can be moved by the beam rails, and whose height is controlled by cables with pulleys, driven by a motor. The spreader is attachable to the four upper corners of the containers by anchoring means, which are usually electro-mechanical elements known as twistlocks. They can also have centering means, such as the fins known as flippers, actuated by the crane operator and which allow the spreader to be centred when placed on the container.

The gantry cranes carry out the transfer of the containers between, for example, the dock and the container vessel. By law, cranes must be handled manually by at least one operator. The operator who manages the crane is usually located in a cabin arranged at the top of the gantry; when the gantry is at the height of the ship, the operator performs a maneuver so that the crane with the spreader moves and descends to the container to be loaded or unloaded, actuates the twistlocks to lock them to the container, hoists it, moves it horizontally and deposits it in the dock. When already on the ground, containers are placed on another means of transport (usually a container truck) or stacked.

It should be noted that in the most modern "semi-automatic" cranes the cabin is virtualized in an attached control building and the operator manages loading and unloading remotely.

Gantry cranes are structures that can measure up to <NUM> meters in height and load more than <NUM>,<NUM> tons. It is obvious that the loading and unloading times of a given container are long, and the amount of energy to operate a gantry crane is high.

To reduce energy consumption and loading and unloading times, the gantry cranes disclosed in documents <CIT> and <CIT> have a beam with spreaders on the side of the ship (ship-side spreaders, hereinafter), spreaders on the land-side (land-side spreaders, hereinafter), and horizontal transport carriages, which offer the possibility of moving a container from the ship-side to the land-side while the ship-side spreader descends to take another container and the land-side spreader ascends to unload the container from the carriage, and then make the runs in reverse.

In turn, document <CIT> shows a crane bridge that extends between two banks of a canal, capable of unloading or loading a container ship that is in the canal. The crane bridge has two groups of spreaders and a trolley for each group, which can work at the same time. For its part, the crane of document <CIT> discloses a trolley with a platform for two containers and with a rotation system to exchange the position of the containers, thanks to which the crane allows unloading a container from the ship in a direction of operation of the spreaders and loading another container on the ship in the opposite direction, but always in parallel to the port line. Another document describing a gantry crane handling containers is known from <CIT>. The crane described in this document discloses the features of the preamble of claim <NUM>.

However, it is appropriate to provide improvements to existing cranes to further facilitate the handling of containers and reduce loading and unloading time.

The aim of the present invention is to provide a gantry crane presenting the advantages described below.

The present invention can be found in claims <NUM> and <NUM> respectively.

As mentioned in the previous section, spreaders are devices that act as a gripping frame, and whose height is controlled by a cable pulley system driven by a motor. The spreaders can be anchored in a dissociable way to the four upper corners of the containers by anchoring means, which are usually electro-mechanical elements known as twistlocks.

Thanks to the present crane configuration, it is possible to lift containers in one section of the beam while simultaneously lowering other containers in another section, preferably at opposite sections of the beam. This technical effect has the advantage of a more time-efficient use the crane by the operators, lifting some spreaders while lowering others while moving the horizontal transport carriage from one side to the other.

Preferably, the crane comprises at least one support carriage, arranged to travel along the first section of the horizontal beam and to support at least one of the ship-side spreaders. Likewise, the crane may comprise a support carriage arranged to travel along the second section of the horizontal beam and to support at least one of the land-side spreaders. In this way, it is possible to load and/or unload containers in different lateral positions.

In a preferred embodiment, the horizontal beam comprises two sets of rails, while the support carriages of the spreaders comprise a set of wheels arranged to move in one of said two sets of rails, while the horizontal transport carriage comprises another set of wheels arranged to move in the other one of said two sets of rails. Preferably, the horizontal beam has a double configuration and one of said two sets of rails is located on the inner faces of the horizontal beam, wherein the set of wheels of the support carriages is arranged to move on said one of the two sets of rails, while the other one of said two sets of rails is located on the upper surface of the horizontal beam and the set of wheels of the horizontal transport carriage is arranged to move on said other one of the two sets of rails.

Another differential aspect of the present crane is that it comprises actuating means arranged to simultaneously actuate the vertical displacement of at least one ship-side spreader and a land-side spreader, said spreaders being operatively linked to each other so that the potential gravitational energy and/or kinetic energy available in the containers lowered with the land-side spreaders can be exploited by the actuating means to lift other containers with the ship-side spreaders. The advantages obtained thanks to this feature consist of:.

In a first embodiment dependent on the foregoing, said actuating means comprise a cable system with at least one cable that operatively links said spreaders to each other, said cable system being susceptible to be actuated by a transmission system. In relation to the transmission system, it may comprise, for example, a gear system, a winch and/or an equivalent system operable by a motor. In a second embodiment, said actuating means comprise an independent cable system for each spreader, wherein a transmission system is arranged to connect to said cable systems in a dissociable way and operatively link them at will. In this latter embodiment, the actuating means can be actuated by a single motor or by independent motors for each spreader.

In turn, optionally, the gantry crane can comprise a regenerative brake in the spreaders and/or in the horizontal transport carriages, so that the kinetic energy available when moving the containers can be recovered by said regenerative brake.

In an optional embodiment of the present gantry crane, it comprises one or more parallel beams under said horizontal beam, at different working heights, with their corresponding horizontal transport carriages. In this way, the alternative use of several ship-side spreaders and descent at the same time is favoured.

As mentioned above, the horizontal transport carriage comprises one or more anchoring assemblies to the containers, which preferably consist of twistlocks, as well as those of the present spreaders.

Preferably, for greater automation of the crane, the ship-side spreaders, the land-side spreaders and/or the horizontal transport carriage comprise speed sensors, position sensors with respect to the containers and/or coupling sensors of the anchoring means and anchoring assemblies.

A complementary aspect of this gantry crane consists of the arrangement of one or more additional horizontal beams in a series configuration to said horizontal beam, which comprise their respective horizontal transport carriages or their respective spreaders, with anchoring means and anchoring assemblies for anchoring to containers either above or under them, to receive them and move them through said additional horizontal beams.

To facilitate the operation of the present gantry crane, said horizontal transport carriage may have a platform for access by an operator, for example, for the control of the anchoring of the containers to the horizontal transport carriage and/or to the land-side spreaders.

According to the invention each anchoring assembly of the horizontal transport carriage comprises a rotation mechanism suitable for rotating the anchoring assembly <NUM>° about its axis of vertical symmetry. As an option, the rotation mechanism consists of a rotating crown (disc-shaped mechanism, widely used to support and rotate the booms of tower cranes of building constructions). The turning crown would be positioned on the vertical symmetry axis of the anchoring assembly, so that its center would be the pivot point. Each rotation mechanism comprises a control system configured to rotate <NUM>° its respective anchoring assembly during the horizontal translation of the carriage, so that each container arrives rotated <NUM>° from one end to the other of the beam. The container goes from being on the ship-side in a position parallel to the port line (which is the position in which it arrives on the ship) to being on the land-side in a position perpendicular to the port line, which is a more suitable position for loading by land vehicles. In a possible subembodiment, the land-side spreaders are positioned perpendicular to the beam. In another possible subembodiment, the land-side spreaders have rotation means, so that they can anchor the containers both in a parallel position and in a position perpendicular to the beam, and thus can unload the containers on the ground in any of the positions. There are several advantages implemented in this preferred embodiment.

Another aspect of the present invention consists of a method of unloading containers by means of a gantry crane as described above. This method is characterized by comprising a first step including simultaneously lifting one or more ship-side spreaders and lowering one or more land-side spreaders. The simultaneous execution of the steps mentioned in this step is what allows to obtain the benefits and advantages described by the present gantry crane.

For greater time efficiency, said step preferably includes simultaneously moving at least one horizontal transport carriage closer to the ship-side spreaders. This step is considered as optional due to the fact that, in certain situations, the horizontal transport carriage may already be adjacent to the ship-side spreaders, for example at the beginning of the unloading of a cargo.

Following any of the previous steps, preferably the method of operation comprises placing at least one horizontal transport carriage under the containers already hoisted by the ship-side spreaders, anchoring the horizontal transport carriage to said containers and undocking the ship-side spreaders from them, while at the same time undocking the land-side spreaders from the containers lowered therewith. As is usual in container unloading, there are operators who control the anchoring of the spreaders to the containers both in the loading area and in the unloading area. Thanks to this step, the time spent by these operators during the unloading of a shipment with several containers is optimized.

Subsequent to the preceding step, the method may comprise a step including simultaneously lifting one or more land-side spreaders, lowering one or more ship-side spreaders, and moving the loaded horizontal transport carriage closer to the land-side spreaders.

Following the preceding step, the method may comprise a step of positioning the containers displaced by the horizontal transport carriages under the land-side spreaders, anchoring the land-side spreaders to said containers, and undocking the horizontal transport carriages of said containers, while anchoring the ship-side spreaders to new containers.

After more than half a century since the development of the first gantry crane and after major innovations applied to the sector, no crane has yet been made public that includes the aforementioned characteristics, works according to the method described here, or provides the valuable advantages mentioned.

For a better understanding of the description made herein, a set of drawings has been provided wherein, schematically, and solely by way of a non-limiting example, a practical case of an embodiment of the gantry crane for containers of the present invention is represented.

An embodiment of the container gantry crane and the method of operation claimed is described below, with reference to <FIG>.

A preferred embodiment of the gantry crane of the present invention is shown in <FIG>, wherein the following can be seen:.

For reasons of clarity, <FIG> does not show the rails or the operator's cab of the gantry crane.

<FIG> shows an enlarged view of inset I in <FIG>. It shows in detail the land-side spreader (<NUM>), the corresponding support carriage (<NUM>), the corresponding cable system (<NUM>) and the corresponding anchoring means (<NUM>) to the container (<NUM>), as well as the horizontal transport carriage (<NUM>), which comprises an anchoring assembly (<NUM>). For sake of clarity, the container (<NUM>) of <FIG> has been depicted with transparent walls.

<FIG> shows a schematic embodiment of the present crane where the cable systems (<NUM>, <NUM>) that maneuver the ship-side spreaders (<NUM>) and the descent land-side spreaders (<NUM>) are linked by a winch (<NUM>), so that the gravitational potential energy and the kinetic energy available when lowering the containers (<NUM>) with the land-side spreaders (<NUM>) is used for the lifting of the containers (<NUM>) by the ship-side spreaders (<NUM>).

<FIG> schematically depicts a gantry crane that has two additional horizontal beams (<NUM>', <NUM>") in a configuration in series with said horizontal beam (<NUM>), which comprise their respective horizontal transport carriages (not shown in the figure) and their respective spreaders (<NUM>'), with means for anchoring to containers (<NUM>), either above or under them, to receive them and move them through said additional horizontal beams (<NUM>', <NUM>").

As regards the method of operation, exemplary steps of unloading a container with the crane depicted in <FIG> have been depicted in <FIG>. In this example, the method comprises a first step (A) including simultaneously lifting the ship-side spreader (<NUM>) with a container (<NUM>) and lowering the land-side spreader (<NUM>) with another container (<NUM>), while moving the horizontal transport carriage (<NUM>) closer to the ship-side spreader (<NUM>).

Next, the method of operation shown comprises a second step (B) which includes placing the horizontal transport carriage (<NUM>) under the container (<NUM>) already hoisted by the ship-side spreader (<NUM>), anchoring the horizontal transport carriage (<NUM>) to said container (<NUM>) and undocking the ship-side spreader (<NUM>), while at the same time undocking the land-side spreader (<NUM>) from the lowered container.

Subsequently, the method of <FIG> shows a third step (C) comprising simultaneously lowering the ship-side spreader (<NUM>), lifting the land-side spreader (<NUM>), and moving the horizontal transport carriage (<NUM>) loaded with a container (<NUM>) closer to the land-side spreader (<NUM>).

To complete the cycle, the method shown in <FIG> comprises a fourth step (D) comprising placing the container (<NUM>) displaced by the horizontal transport carriage (<NUM>) under the land-side spreader (<NUM>), anchoring the land-side spreader (<NUM>) to said container, and undocking the horizontal transport carriage (<NUM>), while anchoring the ship-side spreader (<NUM>) to a new container.

<FIG> shows a second preferred embodiment of the gantry crane of the present invention, where the following can be seen:.

<FIG> illustrates in detail the horizontal transport carriage (<NUM>') under the ship-side spreader (<NUM>), where the anchoring assembly (<NUM>') is supported by the rotation mechanism (<NUM>') for its rotation about its vertical axis (<NUM>') of symmetry.

<FIG> shows an example of the method for unloading containers stored on a ship (not shown for clarity) by means of the crane shown in <FIG>. In this example, the method comprises a first step (A') that includes simultaneously anchoring the ship-side spreader (<NUM>) to one of the containers (<NUM>) of the ship, undocking the container already carried by the horizontal transport carriage (<NUM>') with respect to the anchoring assembly (<NUM>') thereof, and anchoring the land-side spreader (<NUM>') to the said latter container (<NUM>).

Next, the method of operation of <FIG> comprises a second step (B') which includes simultaneously lifting the container (<NUM>) of the ship with the ship-side spreader (<NUM>) while the horizontal transport carriage (<NUM>') is being moved closer to it until it is placed under said container (<NUM>), while the other container (<NUM>) is being lowered with the land-side spreader (<NUM>'). As can be seen, the position of the container <NUM> on the ship-side is perpendicular to the horizontal beam <NUM>, while the position of the container <NUM> on the land-side is parallel to the horizontal beam <NUM>.

Next, the method of operation of <FIG> comprises a third step (C') which includes simultaneously anchoring the horizontal transport carriage (<NUM>') to said container (<NUM>) of the ship and undocking the ship-side spreader (<NUM>), while at the same time undocking the land-side spreader (<NUM>') from the lowered container.

Subsequently, the method of <FIG> shows a fourth stage (D') that includes simultaneously lowering the ship-side spreader (<NUM>), lifting the land-side spreader (<NUM>') and rotating <NUM>° the anchoring assembly (<NUM>') of the horizontal transport carriage (<NUM>'), which is loaded with the container (<NUM>) of the ship, while displacing it until it is located under the land-side spreader (<NUM>').

Finally, the method of operation of <FIG> comprises a fifth stage (E') consisting of repeating the steps of the first stage (A'), but with other containers (<NUM>), as well as repeating successively the remaining stages, such as a sixth stage in which the container (<NUM>) is lowered with the land-side spreader (<NUM>'), etc..

<FIG> shows an example of the method for loading containers from land to the ship with the crane shown in <FIG>. In this example, the method comprises a first step (A") that includes simultaneously anchoring the land-side spreader (<NUM>') to one of the containers (<NUM>) that are on the ground, undocking the container already transported by the horizontal transport carriage (<NUM>') of the anchoring assembly (<NUM>') thereof and anchoring the ship-side spreader (<NUM>) to said latter container (<NUM>).

Next, the method of operation of <FIG> comprises a second step (B") which includes simultaneously lifting the ground container (<NUM>) with the land-side spreader (<NUM>') while the horizontal transport carriage (<NUM>') is moved closer to it until it is placed under said container (<NUM>), while the other container (<NUM>) is lowered with the ship-side spreader (<NUM>). As can be seen, the position of the container <NUM> on the ship-side is perpendicular to the horizontal beam <NUM>, while the position of the container <NUM> on the land-side is parallel to the horizontal beam <NUM>.

Next, the method of operation of <FIG> comprises a third step (C") that simultaneously includes anchoring the horizontal transport carriage (<NUM>') to said ground container (<NUM>) and undocking from it the land-side spreader (<NUM>'), while at the same time undocking the ship-side spreader (<NUM>) from the lowered container.

Subsequently, the method of <FIG> shows a fourth stage (D") that includes simultaneously lowering the land-side spreader (<NUM>'), lifting the ship-side spreader (<NUM>) and rotating <NUM>° the anchoring assembly (<NUM>') of the horizontal transport carriage (<NUM>'), which is loaded with the ground container (<NUM>), while displacing it until it is located below the ship-side spreader (<NUM>).

Finally, the method of operation of <FIG> comprises a fifth stage (E") consisting of repeating the steps of the first stage (A"), but with other containers (<NUM>), as well as repeating successively the rest of the stages, such as a sixth stage in which the container (<NUM>) is lowered with the ship-side spreader (<NUM>), etc..

Claim 1:
Gantry crane for containers having an elevated horizontal beam (<NUM>), comprising:
- one or more ship-side spreaders (<NUM>) arranged to lift one or more containers (<NUM>) and supported on a first section (<NUM>) of said horizontal beam (<NUM>),
- one or more land-side spreaders (<NUM>') arranged to lower one or more containers (<NUM>) and supported on a second section (<NUM>) of said horizontal beam (<NUM>), and
- a horizontal transport carriage (<NUM>') mounted displaceably along the beam so as to be capable of being positioned under the containers (<NUM>) lifted by the ship-side spreaders (<NUM>), and arranged to support said containers and displace them to a position under the land-side spreaders (<NUM>'), said horizontal transport carriage (<NUM>') comprising one or more anchoring assemblies (<NUM>') for anchoring the containers (<NUM>) in a dissociable way,
characterized in that each anchoring assembly (<NUM>') comprises a rotation mechanism (<NUM>') suitable for rotating the anchoring assembly (<NUM>') <NUM>° about its vertical axis (<NUM>') of symmetry.