DE69810075T2 - CRANE - Google Patents

Description

The invention relates to a crane, more precisely not only to a crane suitable for loading and unloading vehicles, conveyor belts or a watercraft such as a ship, but also to the method for operating such a crane.

The invention is described below in connection with the loading and unloading of cargo ships. However, it should be understood that the invention can also be used for the movement of goods and products under all circumstances and within any facility, e.g. for loading or unloading other cargo loading equipment such as motor vehicles or conveyor belts.

Cargo ships form the backbone of global trade, carrying all types of cargo around the world, from bulk materials to freight containers. This cargo can be loaded inside the cargo holds, which are usually covered by movable roof hatches, or externally on deck - which is very common on cargo ships.

Economically, the cargo ship must be unloaded and reloaded as quickly as possible when it is anchored in the port. Currently, these operations are normally carried out by a series of gantry cranes located in the port, each of these gantry cranes being directed at the corresponding ship's roof hatch for access to the cargo holds or, for example, to special containers placed on deck. For this purpose and in conjunction with the cargo ship, the gantry cranes can move along the port.

Each crane (gantry crane) has a rigging (lifting device) that is raised by wires (ropes) from the trolley (carriage or carriage). The trolley (in the sense of a carriage) moves on a raised, horizontal track, which consists of two rails supported by a crane boom (crane arm) or a gantry, and extends between the rails. During an unloading process, it moves back and forth between two points, one of these points being intended for unloading the goods from the ship and the other for depositing these goods in the port. The goods can, for example, be placed in a vehicle, truck or train, or on a conveyor belt that transports the goods to another location. The loading process naturally consists of the same steps, only in reverse order.

A series or group of several cranes operating simultaneously or in parallel allows a faster handling of the load than the continuous operation of a single crane in reaching different points on the vessel. However, there is a speed limit determined by the time it takes for each trolley to be pushed between the two points mentioned above. Consequently, the crane boom remains useless on the vessel for a significant period of the entire operation, waiting for the trolley to return before further cargo can be lifted and unloaded or loaded onto the vessel.

Attempts to speed up the process by providing more than one crane for each hold or point along the vessel are impracticable. Any loading crane is invariably bulky when required to carry significant loads. For this reason, there is insufficient space to operate two such loading cranes side by side without causing mutual interference, even if they are still properly aligned with respect to the vessel and its cargo.

The application is based on the finding that the speed limit of the loading and unloading process could be increased significantly if a single crane could have two or more riggings operating simultaneously and preferably independently of each other. This would have the same effect as if two or more cranes were operating simultaneously and at the same location. It could also be expected that the speed of the process would be multiplied according to the number of riggings used.

In order for the two or more riggings to work along the same gantry and thus take over the work of two or more cranes in the same place, it is essential that the riggings and their loads or hoists are able to pass each other without interference each time. Of course, the structure of the crane itself must also be suitable to ensure safe operation with the force, weights and vibrations caused by the simultaneous operation of multiple hoists.

The applicant found publications of earlier old crane models in various fields of technology, where more than one rigging is provided. These multiple riggings operate on one load and are incapable of accelerating a loading or unloading process consisting of multiple discrete loads. Accordingly, these publications do not lead to this invention, which provides for the simultaneous movement of discrete loads to accelerate the transfer process.

For example, UK patent 1,223,379 was published by Krupp in 1971. It discloses an overhead crane suitable for use in the shipbuilding industry and particularly for moving individual large prefabricated parts of a ship that can weigh several thousand tons. The crane is of gigantic dimensions: it has the shape of a bridge and is supported by columns that are placed at each end, and this crane is mounted on rails on the opposite sides of a dry dock [a shipyard] where a ship is being built.

The Krupp crane is provided with either a horizontal or vertical axis for rotating a single heavy load, as is necessary to rotate a fore-built part of a ship by 90º from its orientation when delivered to the shipyard to that for installation on the ship being built. This is achieved by installing two winches on each side of the bridge, for a total of 4 winches - 2 upper and 2 lower - with the upper pair of winches installed on each side of the bridge and the lower pair of winches installed on each side of the bridge. Cables are provided on each winch to carry the load.

There are various means whereby the upper and lower winch pairs can move past each other without the winches, their cables and tackle or the lifted load interfering with each other's operation. This relative movement between the winch pairs causes the load to rotate as desired, in conjunction with the variation of the cable lengths and optionally with the removal and re-attachment of the cables to different locations on the load during the rotation process.

While the individual winches and the winch pairs are independently movable, their movements are actually always linked to each other. This is because the winch always carries one and the same load; therefore, the winch must move in a constantly coordinated manner within a range of motion that is limited by the total size of the load.

In addition, the Krupp crane was designed for careful and precise orientation of individual, very large loads, making it possible to remove and reconnect cables as the winches match each other. In the present invention, such steps are not necessary. In general, there is no information in the patent for the Krupp crane about the winch movement, which is suitable for large, fast, repetitive and preferably independent movements when loading and unloading a ship. It was also noted that the Krupp crane is not suitable for use on the port side, even when scaled down, as it requires supports at both ends of the bridge.

Patents GB 907,399 and GB 972,477, both by Creusot, predate Krupp's by ten years. They describe cranes for lifting and tipping moving loads in a steelworks. The cranes employ three riggings - two installed on an upper trolley which supports the weight of the scoop, and one installed on a lower trolley which controls the tilting of the scoop. The trolleys travel back and forth on the respective tracks, with the lower trolley travelling on a track which is narrower and lies below the other trolley. In this way, the inner trolley and its rigging can travel inside the riggings during tipping, lifted by the outer trolley, without disturbing the outer trolley or its rigging.

As with Krupp, the Creusot documents deal with the position and orientation of a single load that must be moved slowly and precisely. Therefore, the movements of the various rigging and the range of these movements are constrained. It was also noted that the Creusot cranes would not be suitable for use in port, even in the unlikely event that a person attempting to load and unload a ship would resort to the art of steelmaking for a solution.

In summary, therefore, neither the Krupp nor the Creusot cranes transport separate loads or cargoes quickly and efficiently using a single crane equipped with more than one rigging.

FR-A 2 196 288 to Conrad-Stork B. V. described a crane operating method, which involves the transfer of goods or merchandise in a variety of loads, according to which: each load is carried by a respective carriage which travels reciprocally with respect to the crane along the respective path to transfer the load and return for the next load; the carriages pass each other as they travel back and forth along their respective path; and the configuration of at least one carriage is modified to prevent collision with the other carriage or its load as the carriages pass each other.

FR-A 2 196 288 also described a crane adapted to move goods or merchandise in a variety of loads. The crane consists of a variety of carriages which travel alternately with respect to the crane along the respective path to move the load and return for the next load; the carriages pass each other as they travel back and forth along its respective path; it provides for the modification of the configuration of at least one carriage to avoid collision with the other carriage or its load as the wagons pass each other.

Viewed from both aspects, the invention is characterized in that the change in configuration to prevent a collision involves the movement of one carriage within another carriage.

Preferably, the invention is used in the loading and/or unloading of a cargo conveyance, such as a ship, where the cargo to be moved consists of a variety of loads.

The invention also lies in optional features as set out in the dependent claims.

The invention will now be explained in more detail with reference to the drawings and examples:

Fig. 1 is a simplified perspective view of a gantry crane with two riggings moving past each other without interference throughout a facility;

Fig. 2 is a cross-section of the gantry crane shown in Fig. 1 with tracks arranged in a stepped configuration where the trolleys extend across the track width.

Fig. 3 shows the lateral lifting of the gantry crane shown in Fig. 1 and shows a collision prevention zone;

Fig. 4 is a schematic view below the gantry crane shown in Fig. 1, Fig. 2 and Fig. 3;

In Fig. 5 is a cross-section of a gantry crane having an inner track, a carriage extending across the width of the inner track, and an outer track, the inner and outer tracks forming two parallel rails, each rail carrying a separate half-carriage or winch; and

In Fig. 6 is a cross-section of a gantry crane shown in Figs. 1 to 4, but showing a wire device adapted to unify adapted lifts, such as containers.

Referring to Figures 1 to 4, a gantry crane consists of a raised, extended boom or gantry 15 extending horizontally from a support lift to one end by a boom. The support includes two pairs of beams 16, the beams of each pair separately bending outward, towards the ground, for stability. The gantry 15 forms a frame portion of tubular components made of steel for stability and lightness.

As best shown in Fig. 2, the gantry carries an upper pair of rails 17 and a lower pair of rails 18, respectively; these pairs define the upper and lower tracks in a stepped relationship. Each track supports and guides a respective trolley; the upper track has a relatively wide upper trolley 19 thereon, and the lower track in turn has a relatively narrower lower trolley 20 thereon. Each trolley 19, 20 carries a respective pair of wires 21 which converge downward from the pulley 22 to the rigging 23 and 24, respectively.

The tracks and trolleys 19, 20 are structured so that the lower track and trolley 20 can pass within the wires 21 which depend from the upper trolley 19, thus they are connected to each other. As shown in Figs. 1 to 3, it is also necessary that the tackle 23 be raised above the tackle 24, to a height which allows any load carried by the tackle 23 to safely pass the tackle 24 and its connected wires. However, it is not necessary to remove the load from either the tackle 23 or 24, since the trolleys 19, 20 move past each other.

Safety is of course the most important consideration in any crane system. The primary safety point to be considered when applying this invention is the risk of collision between both loads, rigging and wires, as the rigging moves in concert with each other. This can be prevented by electromechanical sensors and breakers, microprocessor controlled brakes or other logical, equally effective circuit systems.

With reference to Fig. 3, these safety measures can be used to form a 'collision prevention zone' shown in the dashed lines, thus ensuring that the rigging 23 and any load carried by it are progressively lifted from the lower trolley 20 when it reaches a minimum distance from the approaching rigging 24, so that the rigging 23 is at all times sufficiently high to prevent collision. If this does not happen, the safety measures mentioned above should control the situation or stop the movements of the trolleys 19, 20.

Fig. 4 shows the movement of the trolleys 19, 20 as they pass each other and also the way in which the box structure of the portal 15 itself can fix the rails 17, 18. In this arrangement the rails 17, 18 form four parallel longitudinal components connected at their end by transverse components 25. The beams 16 are attached to the upper rails 17, which are also outer rails according to Fig. 4.

In this arrangement, the vertical gap between the upper rails 17 and the lower rails 18 increases the beam stiffness of the structure as a whole. This particular aspect enables the invention to be used to construct jib cranes suitable for use in ports for loading and unloading ships. Of course, this increased stiffness will be beneficial for all cranes, including bridge cranes.

Whilst the embodiment in Figs. 1 to 4 allows the use of trolleys of conventional design, it will be apparent that the lower pair of rails 18 - defining the lower track - can only be supported beyond the desired extremities of movement of the upper trolley 19. This is because any supports attached to the length of the lower track will interfere with either the movement of the lower trolley 19 if they normally extend vertically, or the movement of the tackle 24 and wires 21 of the upper trolley 19 if they normally extend horizontally. Consequently, the application of this embodiment in practice may be limited to lighter loads due to the tilting loads on the lower track.

Referring to Fig. 5, an alternative embodiment of the inventive device employs an inner trolley 26 which rides on an inner pair of rails 27 which forms an inner track similar to the lower track of Figs. 2 and 3. A pair of winches 28 - effectively two halves of an outer trolley - ride outside the tracks 27 on an outer pair of rails 29. However, the device is substantially adapted as can be seen in Figs. 1 to 4. Like numbers refer to like parts.

It will be noted that the removal of the lower trolley of Figs. 2 and 3 enables the inner pair of rails 27 to be supported from above by a gantry at any or all points along its length - e.g., by raising the rails by vertical supports suspended from a gantry frame above (not shown) - without interfering with the movement of the winches 28.

Preferably, the pair of winches should move in precise coordination with one another. This operation could be achieved, for example, by using microprocessor-controlled synchronous motors with electrical gearing. It would also be possible for one winch 28 to inform the other winch 28 of its position, for example by sending infrared signals to the other winch 28, which signals can be interpreted and used to synchronize the movement of the other winches 28. Other electromechanical devices can be incorporated to achieve the same effect.

Finally, in Fig. 6 it is shown that another embodiment of the inventive device corresponds in broad terms to the stepped and boxed embodiment shown in Figs. 1 to 4, like numbers being used again for like parts. This embodiment is adapted to be used with unified elements of standard dimensions, such as 12.19 m (40 ft) long containers; the tackle must usually be sunk under gaps between adjacent stacked containers and into the cell guides in the hold - only as wide as the container itself. In this case a reduction means for the wires to the tackles is required to accommodate [minimize] the space restrictions, e.g. by using wire spatulas and collectors as components of the outer/upper trolley tackle.

An example is the loading and unloading of a container ship as shown in Fig. 6. In this case the loads or lifts are standard containers. Accordingly, the max. transverse dimension of the narrower internal/lower carriage 30 and its tackle 31 is limited to 12.19 m (40 ft).

Of course, the upper/outer trolley 32 must be wider than 12.19 m (40 ft) if its wires are to pass the lower/inner trolley 30; but the tackle 33 of the upper/outer trolley 32 must be brought down to a maximum of 12.19 m (40 ft) width if it is to reach between the adjacent containers 34 and be locked to another container 35. To achieve this, the frame 36 of the wire collection device is lifted by wires 37 below the point where the narrower lower/inner trolley 30 passes its lift by the wider tackle 33.

Many variations are possible without departing from the inventive concept.

For example, the half-cart or winch arrangement shown in Fig. 5 could be applied to the embodiment shown in Fig. 6, which is adapted to work with unified loads.

The above safety measures can be made more effective by automatically controlling the path made by the tackle and consequently any load carried by it. This movement could be programmed in advance according to a stored and possibly padronised movement pattern suitable for the loads in question and/or controlled by sensors that control the traffic of the moving tackle, wires and loads, thus allowing a microprocessor to determine a safe path.

The cranes proposed in the invention can also be controlled manually. In this case, a cabin for the driver could be attached to the relevant trolley or winch or otherwise connected to control the movement of the relevant rigging. If the traffic situation is critical, then it may be the case, e.g. with unified elevators, that the cabins are separated from the trolleys or winches and travel on additional rails which are independent of the rails on which the trolleys travel. In this case, it would be advantageous to synchronize the movement of the cabin with the trolley which controls the cabin. The means of synchronizing the movement of the cabin could be, e.g. as in the above illustration with reference to the embodiment shown in Fig. 5, for synchronizing the movement of the winches 28.

While the above embodiments have two tackles, i.e. one installed inside the other, it would be possible and preferred to have three or more tackles operating in an adapted setup if there is enough space for it.

Of course, it would also be possible to have all the trolleys, including the innermost one, formed by two winches or half trolleys. In addition, the pairs of rails could be arranged at different levels, one above the other, in a stepped structure, while the embodiment of Fig. 5 is shown with the inner and outer pairs of rails substantially at the same level.

Claims (41)

1. A method of operating a crane (14) comprising moving goods or goods in a variety of loads, each load being carried by a corresponding carriage traveling reciprocally with respect to the crane (14) along a respective path to transport the load and return for a next load; the carriages traveling past each other while traveling back and forth along their respective path, and at least one carriage changing configuration to avoid collision with another carriage or its load as the carriages travel past each other, characterized in that the change to avoid collision is related to a carriage passing within another carriage. 2. Method according to claim 1, characterized in that each carriage has a movable lifting device, a lifting means for taking the load from the lifting device and lifting it, and a means for setting up the load. 3. Method according to claim 2, characterized in that the loading means is a tackle (23, 24), a portal or a means for setting up a container. 4. A method according to claim 2, characterized in that the length of the lifting means varies to change the configuration of a carriage. 5. A method according to claim 4, characterized in that the configuration of the carriage is changed during collision avoidance by the lifting means raising or lowering the means for loading. 6. A method according to claim 5, characterized in that the lifting means comprises a first and second strand - one on each side of the load setting means - both strands being extended or shortened together to raise or lower the load. 7. A method according to claim 4, characterized in that the configuration of the carriage is changed during collision avoidance when the lifting means transports the means to the loading device transversely with respect to the general direction of the carriage travel. 8. Method according to one of the preceding claims, characterized in that the carriages travel independently of each other. 9. Method according to one of the preceding claims, characterized in that the carriages travel back and forth over a range of movement which is substantially longer than the distance over which the load is carried. 10. A method according to any preceding claim, characterized in that the carriage configuration for collision prevention is automatically controlled, the configuration being carried out according to a stored, predefined pattern as the carriages travel back and forth. 11. Method according to one of the preceding claims, characterized in that the control of the carriage configuration to avoid collisions also involves the automatic control of the travel of the carriages passing each other, including any load carried by them. 12. Method according to one of the preceding claims, characterized in that the loads are carried by their respective wagons during the entire transport process of the wagons. 13. A crane (14) for moving goods or merchandise in a variety of loads, comprising a plurality of carriages each reciprocally movable with respect to the crane (14) along a respective path to transfer a load and return for a next load; the carriages passing each other and traveling back and forth along their respective path; and means for changing the configuration of at least one carriage to prevent collision with another carriage or its load when the carriages pass each other, characterized in that the configuration change to prevent collisions relates to a carriage passing within another carriage. 14. Crane (14) according to claim 13, characterized in that each carriage has a movable lifting device, a lifting means for taking the load from the lifting device and lifting it, and a means for setting up the load. 15. Crane (14) according to claim 14, characterized in that the means for varying the length of the lifting means is provided in order to change the configuration of a carriage. 16. A crane (14) according to claim 15, characterized in that the lifting means comprises a first and second strand, one on each side of the load arranging means. 17. Crane (14) according to claim 16, characterized in that a means for varying the length of the first and second strands which are connected to each other is provided. 18. Crane (14) according to claim 16, characterized in that a means for varying the relative lengths of the first and second strands is provided. 19. Crane (14) according to one of claims 13 to 18, characterized in that the loading arrangement means is a rigging (23, 24), a portal or a means for arranging a container. 20. Crane (14) according to one of claims 13 to 19, characterized in that the carriages can be moved onto the corresponding tracks, whereby these tracks are connected to one another. 21. Crane (14) according to claim 20, characterized in that the carriages can be moved onto the corresponding tracks, these tracks being in a stepped relationship. 22. Crane (14) according to one of claims 13 to 21, characterized in that an automatically controlled means for collision prevention is provided, which is connected to a storage means for storing a predefined pattern of the carriage design. 23. A crane (14) according to any one of claims 13 to 22, characterized in that an automatic control means is provided for controlling the travel of the carriages passing each other, including any load carried by them. 24. Crane (14) according to one of claims 13 to 23, characterized in that a collision prevention means is provided which is adapted to ensure that the carriage configuration is changed so that the collision is prevented when that carriage reaches a minimum distance from the other approaching carriage. 25. Crane (14) according to one of claims 13 to 24, characterized in that a raised extended crane boom [crane arm] or a portal (15) is provided which extends horizontally from a vertical support lift to one end through a boom. 26. Crane (14) according to claim 25, characterized in that the crane boom [crane arm] or the portal (15) is a frame of structural elements, including upper (17) and lower (18) rails, wherein the rails form the upper and lower tracks which are in a stepped relationship and a carriage can be driven onto the corresponding track. 27. Crane (14) according to claim 25 or 26, characterized in that the rails are parallel longitudinal elements which are connected at their ends by transverse elements (25). 28. Crane (14) according to one of claims 25 to 27, characterized in that the supports are connected to the rails which are constructed on the outermost side. 29. Crane (14) according to one of claims 13 to 28, characterized in that the tracks support and extend over a corresponding movable lifting device; that an upper track has an upper relatively wide conveyor trolley (19) on it, and a lower track in turn has a lower relatively narrow conveyor trolley (20) on it. 30. Crane (14) according to claim 29, characterized in that the lower track and the lower lifting device run within the lifting means which depends from the upper lifting device. 31. Crane (14) according to one of claims 13 to 30, characterized in that a pair of winches (28) running on a pair of outer rails installed externally and each side of an inner track, a winch (28) running on a corresponding outer rail are provided. 32. Crane (14) according to claim 31, characterized in that a means for transporting the winches (28) in mutual coordination is provided. 33. Crane (14) according to claim 31 or 32, characterized in that the inner track has at least one rail which is supported from above at one or all points of its functional length. 34. Crane (14) according to one of claims 13 to 33, characterized in that the crane is adapted for use with standardized objects of standard dimensions. 35. Crane (14) according to claim 34, characterized in that the standardized items are standard containers. 36. A crane (14) according to claim 35, characterized in that the means for loading equipment is capable of being lowered into a gap between adjacent stacked containers or cell leaders, being substantially as wide as the container itself. 37. Crane (14) according to claim 36, characterized in that a reducing means operates on a lifting means which lifts the means to the loading device. 38. Crane (14) according to one of claims 13 to 37, characterized in that a cabin for the driver is attached or otherwise connected to the corresponding carriage in order to follow the movement of the corresponding carriage. 39. Crane (14) according to claim 38, characterized in that the cabins are separated from the cars and travel on reserved tracks. 40. Crane (14) according to claim 39, characterized in that a means for synchronizing the movements of the cabins with the movements of the carriage controlled by the cabin is provided. 41. Crane (14) according to one of claims 13 to 40, characterized in that three or more tackles functioning in a complete device are provided.