[0001] The present invention relates to a lifting device for pulp units.

BACKGROUND [0002] This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.

[0003] Lifting devices are used for moving pulp units from a source load handling area and a target load handling area. A lifting device comprises pairs of claw wagons that are connected to a hydraulic system of a crane. Claws of the claw wagons are operated together by the hydraulic system for gripping and releasing pulp units by their binding wires.

[0004] When the lifting device is fully loaded at the source load handling area and all claw wagons of the lifting device are gripping pulp units, releasing the pulp units at the target load handling area may not be possible due to the target load handling area lacking enough space for the pulp units carried by the lifting device. Even if the target load handling area would have enough space for the pulp units, a configuration for storing pulp units at the target load handling area may not have available space for the pulp unit loaded to the lifting device. For example, it may be that the pulp units cannot be released to a single location at the target load handling area or the released pulp units would use space reserved for passageways of load handling machinery and personnel. Therefore, if the pulp units would be released at the target load handling area, the released pulp units could cause a risk to safety for load handling machinery and personnel at the target load handling area.

SUMMARY

[0005] The scope of protection sought for various embodiments of the invention is set out by the independent claims. The embodiments, examples and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various embodiments of the invention.

[0006] According to a first aspect there is provided a lifting device for pulp units comprising: one or more claw wagons, said claw wagons comprising gripping means operatively connected to electric actuators for gripping and releasing pulp units by the gripping means; a controller unit configured to connect to a control bus of a crane and said controller unit being connected to the electric actuators of the claw wagons, and the controller unit is arranged to: in response to receiving at least one control command from the control bus of the crane, to control at least one claw wagon, more than one claw wagon, at least one pair of the claw wagons, a part of the claw wagons or all of the claw wagons for gripping or releasing pulp units by the gripping means of the controlled at least one claw wagon, more than one claw wagon, at least one pair of the claw wagons, part of the claw wagons or all of the claw wagons.

[0007] According to a second aspect there is provided a method for lifting pulp units comprising: receiving, by a controller unit of a lifting device for pulp units, said lifting device comprising one or more claw wagons and said claw wagons comprising gripping means operatively connected to electric actuators for gripping and releasing pulp units by the gripping means, said controller unit configured to connect to a control bus of a crane and said controller unit being connected to the electric actuators of the claw wagons, at least one control command from the control bus of the crane; and controlling, by the controller unit, in response to receiving said at least one control command from the control bus of the crane, at least one claw wagon, more than one claw wagon, at least one pair of the claw wagons, a part of the claw wagons or all of the claw wagons for gripping or releasing pulp units by the gripping means of the controlled at least one claw wagon, more than one claw wagon, at least one pair of the claw wagons, part of the claw wagons or all of the claw wagons. [0008] According to a third aspect there is provided a crane comprising a crane control bus connected to a lifting device according to an aspect.

BRIEF DESCRIPTION OF THE DRAWINGS [0009] For a more complete understanding of example embodiments of the present invention, reference is now made to the following descriptions taken in connection with the accompanying drawings in which:

[0010] Figs. 1a and 1b illustrate a lifting device for pulp units in accordance with at least some embodiments of the present invention; [0011] Fig. 2 illustrates configurations for storing pulp units in a load handling area in accordance with at least some embodiments of the present invention; [0012] Figs. 3 to 6 illustrate an example of a lifting device in accordance with at least some embodiments of the present invention;

[0013] Fig. 7 illustrates an example of a lifting device for pulp units in accordance with at least some embodiments of the present invention;

[0014] Figs. 8-10 illustrate examples of methods for a lifting device in accordance with at least some embodiments of the present invention;

[0015] Fig. 11 illustrates an example of a block diagram of a lifting device in accordance with at least some embodiments of the present invention; [0016] Fig. 12 illustrates an example of gripping position and release position of gripping means of a claw wagon in accordance with at least some embodiments of the present invention; and

[0017] Fig. 13 illustrates an example of a method for a lifting device in accordance with at least some embodiments of the present invention.

DETAILED DESCRIPTON OF SOME EXAMPLE EMBODIMENTS

[0018] The following embodiments are exemplary. Although the specification may refer to "an", "one", or "some" embodiment(s) in several locations, this does not necessarily mean that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. [0019] There is provided a lifting device for pulp units comprising one or more claw wagons, said claw wagons comprising gripping means operatively connected to electric actuators for gripping and releasing pulp units by the gripping means, a controller unit configured to connect to a control bus of a crane and said controller unit being connected to the electric actuators of the claw wagons, and the controller unit is arranged to: in response to receiving at least one control command from the control bus of the crane, to control at least one claw wagon for gripping or releasing pulp units by the gripping means of the at least one claw wagon. The lifting device provides a reduced risk of contaminating the pulp units and selective control of claw wagons. The lifting device can handle the pulp units without a hydraulic system driving the gripping means, whereby a risk of contaminating the pulp units by spillage of hydraulic oil on the pulp units may be reduced. The claw wagons can be controlled as needed and it is not necessary to control all the claw wagons to grip or release pulp units. This is advantageous since a fewer pulp units than a total capacity of the lifting device for carrying pulp units may be gripped or released at a time. The pulp units handled by the lifting device may be of various qualities.

[0020] It should be noted that some examples are described herein in the context of controlling at least one claw wagon of a lifting device in response to receiving at least one control command. However, the examples may also be applied in the context of controlling more than one claw wagon, at least one pair of the claw wagons, a part of the claw wagons of the lifting device or all of the claw wagons of the lifting device in response to the at least one control command. Accordingly, the examples described herein provide a lifting device, corresponding method and a crane for adaptively controlling claw wagons of the lifting device. [0021] It should be noted that some examples are described herein in the context of a lifting device for example a control unit of the lifting device performing one or more functionalities in response to a control command or at least one control command. However, the examples may also be applied, when the number of control commands is higher. For example, each functionality may be caused by a single/dedicated control command. On the other hand, a single/dedicated control command may cause more than one or even all functionalities described in an example.

[0022] A lifting device provides handling of one or more pulp units by gripping to the pulp units at a source load handling area and releasing the pulp units at a target load handling area. The lifting device may comprise gripping means for gripping and releasing the pulp units. The gripping means may be configured to attach to the pulp units by gripping the binding wires of the pulp units. The gripping means may be configured to detach from the pulp units by releasing the binding wires of the pulp units. The gripping means may be operatively connected to electric actuators for driving the gripping means between a gripping position and a release position. The pulp units may be gripped by the gripping means, when the gripping means are driven by the electric actuators to a gripping position. The pulp units may be released by the gripping means, when the gripping means are driven by the electric actuators to a release position.

[0023] Binding wires are used to bind pulp bales into pulp units for transportation of the pulp units by conveyors or by lifting the pulp units by the binding wires. The binding wires may be of steel or other material that provides sufficient strength for lifting the pulp units by the binding wires.

[0024] A pulp unit may comprise a plural number of pulp bales bound into pulp units by binding or unit wires. A commonly used pulp unit consists of eight pulp bales. A lifting device may be capable of lifting a plural number of pulp units, even 20 units at a time, provided that a crane connected to the lifting device has enough lifting capacity. Typically, one or more binding wires are wound around each pulp unit. The binding wires are typically gripped by gripping means of two claw wagons. [0025] A crane is a load handling device for moving load from one location to another by lifting the load. Examples of cranes comprise at least bridge cranes, gantry cranes and hoisting cranes. The crane may be fixed to a location in an area or the crane may be movable between locations. Examples of movable cranes comprise cranes movable on rails, such as rail-mounted gantry crane, and tires, such as tire-mounted gantry cranes. The crane comprises a crane control bus for controlling load handling operations such as gripping and releasing pulp units by a lifting device. Cranes are used for example in harbors and warehouses for transferring load between one or more forms of transportation. Forms of the transportation may comprise at least maritime, land and air transportation. Accordingly, the cranes may transfer loads between the same or different forms of transportation.

[0026] A load handling area may comprise a harbor, a warehouse, a terminal, a vehicle, or a part thereof. The load handling area may have a surface, e.g. the ground or a floor, on which pulp units may be stored. Examples of the vehicles comprise ships, river barges, trucks, trailers, carriages and railroad cars. The load handling area may comprise one or more of storage areas for pulp units and/or passageways for personnel and/or machinery. The pulp units may be stored in the load handling area in a configuration for storing pulp units. A load handling area where pulp units are loaded to a lifting device by the lifting device gripping the pulp units may be referred to a source load handling area. A load handling area where pulp units are unloaded to a lifting device by the lifting device releasing the pulp units may be referred to a target load handling area. The source load handling area and the target load handling area may have different configurations for storing pulp units.

[0027] A configuration for storing of pulp units may define locations for storing the pulp units within a load handling area. The locations may be defined by positions in a coordinate system e.g. by a two-dimensional or a three-dimensional coordinate system within the load handling area. Outdoor positioning systems and/or indoor positioning systems may be used for defining the positions. The configuration provides that the pulp units are located out of passageways of machinery and/or personnel in the load handling area, whereby safety in load handling may be supported. Examples of the configurations comprise at least rows of pulp units. The configuration may comprise one or more rows of pulp units, whereby each row may have different numbers of pulp units, or at least some or all of the rows may have the same number of pulp units. The rows may be stacked on top of each other. Pulp units that are arranged in the configuration may be gripped by a lifting device and moved to a target load handling area.

[0028] An electric actuator comprises at least an electric motor that converts electrical energy into mechanical energy. The mechanical energy may be kinetic energy of a mechanical movement, for example a rotational movement or linear movement, of an output member, e.g. an axis, of the electric actuator. The electric actuator may comprise an axis that is rotated by the electrical energy, whereby the electrical energy is converted into a mechanical torque of the axis. The mechanical torque of the axis may be communicated by gear(s) to gripping means for driving the gripping means. An example of the electric motor is an AC motor driven by Alternating Current (AC). The electric actuator may comprise an adjustable speed drive or a variable-frequency drive connected to the AC motor to control speed and torque by varying input frequency and voltage of the AC motor.

[0029] Gripping means comprises a claw, a claw-like structure or a claw-like member. A claw wagon may comprise a pair of gripping means or claws, where the gripping means or claws may be moved towards each other for gripping pulp units and away from each other for releasing pulp units. The claws in a pair of claws may be arranged opposite to each other in a horizontal direction. The claw may be made of steel or other material of sufficient strength. The claw has an elongated shape such that a binding wire may be securely supported by the claw in a gripping position of the claw, when the binding wire runs in a direction that is transverse to a longitudinal direction of the claw and the width of the binding wire is substantially less than a length of the claw. Examples of the claw and claw-like structures for gripping pulp units are well-known to the skilled person from lifting devices that are commercially available by Stevenel Oy.

[0030] Figs. 1a and 1 b illustrate a lifting device for pulp units in accordance with at least some embodiments of the present invention. The lifting device 104 may be connected to a crane 102, when handling pulp units within a load handling area 112. Views ‘1a-T and ‘1 b-1 ’ show the lifting device as seen from an end side and views and ‘1a-2’ and ‘1 b-2’ show the lifting device as seen from an elongated side that connects opposite end sides of the lifting device. The lifting device 104 comprises one or more claw wagons 110. The claw wagons comprise gripping means operatively connected to electric actuators for gripping and releasing pulp units 106 by the gripping means. The gripping means attach to the pulp units by gripping the binding wires 108 of the pulp units. Fig. 1a shows pulp units attached to all claw wagons and gripping means 107 of the claw wagons in gripping positions. The lifting device comprises a controller unit 114 configured to connect to a control bus of the crane and said controller unit being connected to the electric actuators of the claw wagons. When the lifting device is connected to the crane the controller unit is connected to the control bus of the crane. Flowever, it should be appreciated that the lifting device may be at least temporarily disconnected from the crane. [0031] Referring to Fig. 1a, the lifting device is illustrated 104, when fully loaded with pulp units. The lifting device may have been loaded with pulp units at a source load handling area, whereby all the claw wagons are gripped to pulp units. Since all the claw wagons are gripped to pulp units, the capacity of the lifting device in terms of the number of pulp units is fully utilized. In this way pulp units may be efficiently moved from a source load handling area to a target load handling area. [0032] Referring to Fig. 1 b, the lifting device is illustrated 104, when at least a part of the claw wagons is free from pulp units. The claw wagons that are free from pulp units are not gripped to pulp units. At least part of the claw wagons may be free from pulp units, when the lifting device has released one or more pulp units to a target load handling area. The pulp units may be released for example after the lifting device 104 has been loaded with pulp units at a source load handling area and the pulp units are gripped to all the claw wagons in accordance with the illustration of Fig. 1 A. It should be appreciated that when at least a part of the claw wagons is free from pulp units, the lifting device may be loaded with one or more further pulp units to improve utilization of or fully utilize the capacity of the lifting device in terms of the number of pulp units. Further pulp units may be loaded for example from the target load handling area. In this way the pulp units at the target load handling area may be picked up by the lifting device for arranging the pulp units in accordance with a configuration for storing pulp units at the target load handling area.

[0033] Fig. 2 illustrates configurations for storing pulp units in a load handling area in accordance with at least some embodiments of the present invention. The load handling area 202 comprises cargo space of a ship. The cargo space comprises a configuration for storing pulp units within the cargo space. The configuration comprises rows 204, 206, 208, 210 of pulp units. The rows may comprise different numbers of pulp units. It should be appreciated that also other configurations that define locations for storing the pulp units within a load handling area such as the cargo space are feasible.

[0034] Figs. 3 to 6 illustrate an example of a lifting device in accordance with at least some embodiments of the present invention. The lifting device 304 comprises one or more claw wagons 306, the claw wagons comprise gripping means 314 operatively connected to electric actuators 308 for gripping and releasing pulp units by the gripping means.

[0035] Examples of the gripping means comprise claws, claw-like members or elongated members. The gripping means may be arranged to the claw wagons 306 in pairs, whereby a pair of gripping means comprises a pair of claws that may be moved by at least one electric actuator 308 towards each other for gripping pulp units and away from each other for releasing pulp units.

[0036] In an example in accordance with at least some embodiments of the present invention, the lifting device 304 may comprise claw wagons 306 attached side-by-side on both sides of a main beam 310 of a beam framework. Fig. 3 is a perspective view of the lifting device from an elevated viewpoint and showing adjacent sides of the lifting device. Fig. 4 is a view of the lifting device from an elongated side of the lifting device. The elongated side connects opposite end sides of the lifting device. Fig. 5 is a view of the lifting device seen from an end side 305 that is adjacent to the elongated side. Fig. 6 illustrates a view of the cross-section ‘A’ in Fig. 4.

[0037] In an example in accordance with at least some embodiments of the present invention the lifting device 304 may comprise a beam framework configured to be connected detachably to a crane. The beam framework has a longish main beam 310 and cross-beams 312 attached substantially perpendicularly to the main beam. The claw wagons 306 for gripping and releasing pulp units may be connected to the cross-beams. The cross-beams may extend away from the main beam on one or both sides of the main beam. In this way the claw wagons may be connected to the cross-beams either on one or both sides of the main beam. The cross-beams may be at fixed positions or the claw wagons may be movable along a longitudinal direction of the main beam. Accordingly, the lifting device may comprise more than one, for example two, three, four, five, six, seven , eight, ten or more claw wagons or pairs of claw wagons that may be attached to the main beam by cross-beams. [0038] In an example in accordance with at least some embodiments of the present invention, the electric actuators 308 may be connected by gears, or a transmission mechanism, 316 to the gripping means. The gears may be configured to transform a mechanical, e.g. rotational or linear, movement of the electric actuators into movement of the gripping means. Examples of the mechanical movement comprise at least a rotational movement and a linear movement of an output member of the electric actuator. In this way the gripping means may be driven from a release position to a gripping position and from a gripping position to a release position. In an example the gears may be bevel gears. In this way the electric actuators may be positioned more freely with respect to the claw wagons. [0039] In an example in accordance with at least some embodiments of the present invention, the lifting device 304 comprises a transmission mechanism, or one or more gears 316, operatively connected to an electric actuator 308 at each of the controlled at least one claw wagon, more than one claw wagon, at least one pair of the claw wagons, part of the claw wagons or all of the claw wagons, and the transmission mechanism is configured to be driven by the electric actuator for transforming a mechanical, e.g. a rotational, movement of the electric actuator into a movement of the gripping means 314 towards each other for gripping the pulp units or a movement away from each other for releasing the pulp units. Examples of the mechanical movement comprise at least a rotational movement or a linear movement of an output member of the electric actuator. Accordingly, both gripping and releasing of pulp units may be supported by the transmission mechanism that transforms the mechanical movement. It should be noted that a single transmission mechanism may be sufficient to drive a single pair of gripping means, or claws using a single transmission mechanism to drive a single pair of gripping means provides that the movement of the gripping means of the pair is synchronous, whereby safety of gripping and releasing pulp units may be supported. .

[0040] In an example in accordance with at least some embodiments of the present invention, the movement of the gripping means 314 may be synchronous. In this way the gripping means may be moved in a controlled manner regarding distance and timing of the movement, whereby safety of gripping and releasing pulp units may be supported.

[0041] In an example in accordance with at least some embodiments of the present invention, the claw wagons 304 are configured for gripping or releasing pulp units from binding wires wound around the pulp units. Shape of the gripping means and/or movement of the gripping means may be configured for gripping or releasing pulp units from binding wires wound around the pulp units. For example, the gripping means may be shaped for supporting a movement from a gripping position to a release position. Suitable shapes of the gripping means comprise at least elongated shapes, where a head of the gripping means may be formed to facilitate sliding on a surface of a pulp unit and/or under the binding wires that run on the surface around the pulp unit. Then gripping means may be arranged opposite to each other for moving the opposite gripping means towards each other for gripping the binding wires. Additionally or alternatively, the gripping means may be configured to move away from each other for having sufficient room between them for letting binding wires between the gripping means positioned on opposite sides of the binding wires. In this position he gripping means are in a release position. From the release position, the gripping means may be moved towards each other into a gripping position of the gripping means, where the gripping means are parallel. In the gripping position, parallel portions of the gripping means support the binding wires on top of the gripping means, whereby the pulp units may be lifted from the binding wires. The binding wires may run on an upper surface of the pulp units. When gripping a pulp unit, the gripping means may be initially on opposite sides of the binding wires in a horizontal direction. This position may be referred to a release position. Then, the gripping means may be moved towards each other under the binding wires, thus between the binding wires and the upper surface of the pulp unit and the gripping means may reach a gripping position. The gripping position is illustrated in view ‘12A’ and the release position is illustrated in view ‘12B’ in Fig. 12. [0042] In an example in accordance with at least some embodiments of the present invention, the gripping means 314 comprise a locking mechanism 315. The locking mechanism provides that the gripping means may be mechanically locked to a gripping position. The locking mechanism may be configured to be actuated for locking the gripping means, when the lifting device has been lifted to a desired height above the pulp units. In an example, when the claw wagon is on a pulp unit and the weight of the claw wagon is at least partially supported by the pulp unit, the locking mechanism may be mechanically dispositioned by the pulp unit to a position, where the gripping means are unlocked. When the lifting device is lifted to the desired height, the locking mechanism is not dispositioned by the pulp unit, whereby the gripping means are locked. The actuation of the locking may be determined by a locking mechanism sensor deployed to the claw wagon for monitoring the locking mechanism.

[0043] Fig. 7 illustrates an example of a lifting device for pulp units in accordance with at least some embodiments of the present invention. The lifting device 700 is illustrated as seen from above when located on a load handling area. The lifting device may comprise claw wagons 702 attached to more than one beam 710, 712, for example, two, three, four, five, six or more beams, of a beam framework. In this way the lifting device may be used to pick-up more than one row 704 of pulp units 706 from the load handling area. Accordingly, each of the beams may be used for handling one row of pulp units and comprise one or more pairs of claw wagons that each can attach to a pulp unit. The beams 710,712 may be configured to extend substantially parallel to each other. The claw wagons may be movable along a longitudinal direction of the beams 710,712.

[0044] Figs. 8-10 illustrate examples of methods for a lifting device in accordance with at least some embodiments of the present invention. The methods provide handling pulp units without a hydraulic system driving, whereby a risk of contaminating the pulp units by spillage of hydraulic oil may be reduced. The methods provide that only a one, or a part of the claw wagons may be controlled to grip or release pulp units. The methods may be performed by a lifting device comprising one or more claw wagons and the claw wagons comprising gripping means operatively connected to electric actuators for gripping and releasing pulp units by the gripping means. The controller unit is configured to connect to a control bus of a crane and said controller unit is connected to the electric actuators of the claw wagons and arranged to perform one or more phases of the methods.

[0045] Phase 802 of Fig. 8 comprises receiving, by the controller unit of a lifting device for pulp units, at least one control command from the control bus of the crane. [0046] Phase 804 comprises controlling, by the controller unit, in response to receiving said at least one control command from the control bus of the crane, at least one claw wagon for gripping or releasing pulp units by the gripping means of the at least one claw wagon.

[0047] In an example in accordance with at least some embodiments of the present invention, phase 804 comprises that, in response to receiving said at least one control command from the control bus of the crane, the controller unit is arranged to cause an actuation of a locking feature or a braking feature of one or more of the electric actuators. An electric actuator may comprise a locking feature or a braking feature for keeping the gripping means to a gripping position. In an example, when actuated, the locking feature or braking feature causes that the electric actuator is prevented from moving the gripping means to a release position from a gripping position of the gripping means, or the electric actuator is prevented from moving the gripping means to the gripping position from the release position of the gripping means, or both.

[0048] In an example in accordance with at least some embodiments of the present invention, phase 804 comprises that, the control unit controls the electric actuator at each of the controlled at least one claw wagon, more than one claw wagon, at least one pair of the claw wagons, part of the claw wagons or all of the claw wagons, to move the gripping means towards each other for gripping the pulp units or away from each other for releasing the pulp units. The lifting device may comprise a transmission mechanism operatively connected to an electric actuator at each of the controlled at least one claw wagon, more than one claw wagon, at least one pair of the claw wagons, part of the claw wagons or all of the claw wagons, and the transmission mechanism is configured to be driven by the electric actuator for transforming a mechanical movement of the electric actuator into a movement of the gripping means towards each other for gripping the pulp units or away from each other for releasing the pulp units. In this way both gripping and releasing pulp units may be supported.

[0049] In an example in accordance with at least some embodiments of the present invention, phase 802 comprises that the at least one control command is for controlling at least one claw wagon, more than one claw wagon, at least one pair of the claw wagons, a part of the claw wagons or all of the claw wagons and the phase 804 comprises controlling the at least one claw wagon, more than one claw wagon, the part of the claw wagons or all of the claw wagons for gripping or releasing pulp units. In an example, the at least control command may comprise information identifying the controlled claw wagons, whereby the controller unit may decode the information identifying the controlled claw wagons from the at least one control command and cause the gripping means of the identified claw wagons to move to a gripping position or to a release position. The movement to the gripping position may be caused e.g. by the controller unit generating a control signal that is communicated to the electric actuators of the controlled claw wagons, whereby the electric actuators may move the gripping means to the gripping position or to the release position as controlled by the control signal. The control signal may e.g. cause the electric actuator to be driven in a selected direction that corresponds with the gripping position or the release position.

[0050] In an example in accordance with at least some embodiments of the present invention, phase 802 comprises that the controlled at least one claw wagon, more than one claw wagon, at least one pair of the claw wagons, part of the claw wagons or all of the claw wagons of the one or more claw wagons of the lifting device are determined based on the received at least one control command and the phase 804 comprises that the controlled at least one claw wagon, more than one claw wagon, at least one pair of the claw wagons, part of the claw wagons or all of the claw wagons are controlled to grip pulp units or release pulp units, based on the received at least one control command.

[0051] In an example in accordance with at least some embodiments of the present invention, phase 802 comprises that the at least one control command comprises information indicating said one or more claw wagons and at least one of a gripping operation or a release operation. The information included in the control command may be used to control the gripping means of the claw wagons. Since the control commands include the information indicating the controlled claw wagons, the controller unit may determine the claw wagons that are to be controlled to perform the release operation or the gripping operation. In this way only a part of the claw wagons may be controlled. The control command may be in accordance with a format of a communications protocol of the crane control bus.

[0052] It should be appreciated that a gripping operation refers to an operation of the lifting device, where gripping means of one or more claw wagons indicated by the control command are moved to a gripping position.

[0053] It should be appreciated that a release operation refers to an operation of the lifting device, where gripping means of one or more claw wagons indicated by the control command are moved to a release position.

[0054] In an example in accordance with at least some embodiments of the present invention, the lifting device comprises more than one claw wagon and phase 804 comprises, in response to receiving said at least one control command from the control bus of the crane, controlling, by the controller unit, a part of the claw wagons for gripping or releasing pulp units by the gripping means of the part of the claw wagons. Accordingly, the part of the claw wagons may be in practice any number of claw wagons. For example, claw wagons in one end of the lifting device, e.g. a half of the claw wagons, may be controlled. In another example claw wagons that are positioned next to each other may be controlled for gripping or releasing pulp units that are side-by-side.

[0055] In an example in accordance with at least some embodiments of the present invention, the claw wagons comprise pairs of claw wagons and phase 804 comprises in response to receiving said at least one control command from the control bus of the crane, controlling, by the controller unit, at least one pair of the claw wagons for gripping or releasing pulp units by the gripping means of the at least one pair of the claw wagons. For example, a pair of claw wagons located on opposite sides of a main beam of the lifting device may be used to attach to a single pulp unit. In another example, a pair of claw wagons for attaching to a single pulp unit may be installed to the same beam. The lifting device may comprise more than one beam for processing more than one row of pulp units at a time. When more than one pair of claw wagons is controlled, the claw wagon pairs may be side-by-side of the lifting device, for example in one end of the lifting device.

[0056] The method of Fig. 9 provides that a current position of gripping means may be utilized for processing control commands received from the crane control bus. Phase 902 of Fig. 9 comprises determining one or more positions of gripping means of one or more controlled claw wagons.

[0057] Phase 904 comprises determining whether the gripping means of the controlled at least one claw wagon is in a release position or in a gripping position. If the gripping means are in a gripping position the method proceeds to 906. If the gripping means are in a release position the method proceeds to 912.

[0058] Phases 906 and 912 comprise sending information indicating the determined positions of the gripping means. Phase 906 comprises sending information indicating that the gripping means are in a gripping position. Phase 912 comprises sending information indicating that the gripping means are in a release position. It should be appreciated that the determined positions in phases 906 and 912 may comprise positions of the gripping means of one or more controlled claw wagons that may comprise at least one claw wagon, a part of the claw wagons or all the claw wagons. In an example, the sent information may comprise a release position or a gripping position for a specific gripping means and/or a claw wagon comprising the gripping means. The gripping means and/or the claw wagon may be identified by an identifier. Additionally, if a position of the gripping means is not determined as either a release or a gripping position, the sent information may indicate that the position is not determined. This may be used to determine malfunctions. The determined positions, and the undetermined positions, may be sent specific to each claw wagon and/gripping means, for example in a data structure such as a list. The sent information may be structured in accordance with the crane control bus. [0059] Phase 908 comprises determining whether a control command comprises information indicating the gripping operation. The control command may be received in accordance with phase 802. If the control command comprises information indicating the gripping operation, the method proceeds to phase 910 comprising omitting to control the gripping means of the claw wagons to the gripping position. In this way unnecessary control and driving of the gripping means may be avoided. It should be appreciated that the omitting of the control may be logged and/or a notification regarding the omitting of the control may be sent to the crane for performance analysis and detecting malfunctions. If the control command does not comprise information indicating the gripping operation, but e.g. a release operation, the method proceeds to phase 918, whereby the method ends after processing the control command based on position of the gripping means.

[0060] Phase 914 comprises determining whether a control command comprises information indicating the release operation. The control command may be received in accordance with phase 802. If the control command comprises information indicating the release operation, the method proceeds to phase 916 comprising omitting to control the gripping means of the claw wagons to the release position. In this way unnecessary control and driving of the gripping means may be avoided. It should be appreciated that the omitting of the control may be logged and/or a notification regarding the omitting of the control may be sent to the crane for performance analysis and detecting malfunctions. If the control command does not comprise information indicating the release operation, but e.g. a gripping operation, the method proceeds to phase 918. In phase 918 the method ends after processing the control command based on positions of the gripping means, for example in accordance with phase 804 of Fig. 8.

[0061] The method of Fig. 10 provides detecting faults in attachment of pulp units to claw wagons controlled by control commands from a crane. The method may be performed after phase 804, where one or more claw wagons are controlled for gripping pulp units. Phase 1002 of Fig. 10 comprises determining, by the controller unit, actuation of a locking of the gripping means of the controlled at least one claw wagon. Phase 1004 comprises monitoring, by the controller unit, binding wires gripped by the gripping means of the controlled at least one claw wagon. Phase 1006 comprises determining, by the controller unit, after the actuation of the locking, on the basis of the monitoring of the binding wires, a fault in attachment of at least one pulp unit to the controlled at least one claw wagon. Phase 1008 comprises sending, by the controller unit, the crane information indicating the determined fault. Since the crane is provided information of the attachment of the binding wires to the controlled claw wagon after the locking has been actuated, the crane may detect potentially unsafe lifting.

[0062] In an example phase 1002 comprises determining that the gripping means are locked to the gripping position by a locking mechanism. Once the locking mechanism is actuated the lift is being performed and the weight of the pulp units is carried by the gripping means via the binding wires that rest on the gripping means. The actuation of the locking may be determined by a locking mechanism sensor deployed to the claw wagon for monitoring the locking mechanism.

[0063] In an example phase 1004 comprises that the binding wires are monitored by one or more binding wire sensors. A binding wire sensor may detect a presence of binding wires. The binding wire sensor may be deployed in a position providing monitoring by the binding wire sensors when the gripping means are in a gripping position and attached to binding wires. Suitable positions for the binding wire sensors comprise at least positions, where the binding wires resting on the gripping means in a gripping position are within a sensitivity range of the binding wire sensor.

[0064] In an example phase 1006 comprises that at least one binding wire sensor detects an absence of one or more binding wires. This means that the lift is not safe and there is a fault. Since the absence is determined after the locking is actuated, the fault may be determined specific to the controlled claw wagon and ongoing lift, whereby fault detection and correction is facilitated.

[0065] Fig. 11 illustrates an example of a block diagram of a lifting device in accordance with at least some embodiments of the present invention. The lifting device comprises a controller unit 1102 and claw wagons 1103. The claw wagons comprise electric actuators 1106 and sensors 1118, 1120, 1122, 1124, 1126, 1128. The controller unit comprises a processing unit 1108 that comprises a processor 1110 and a memory 1112, an interface to crane control bus 1114, i.e. the control bus of the crane, and an interface to claw wagons 1116. The interface to crane control bus 1114 provides communications of the lifting device with a crane. Accordingly, the interface to crane control bus 1114 provides the controller unit to establish a connection with the control bus of the crane. The communications of the lifting device with a crane may comprise communications of data and commands. For example, the lifting device may receive one or more commands from the crane via the crane control bus for gripping or releasing pulp units. For example, the lifting device may send the crane data such as information indicating faults and/or positions of gripping means. The interface to crane control bus 1114 may be implemented using a wired or wireless connection. The wires or wireless connection may be in accordance with CAN (Controller Area network), Profibus, Scanbus or Ethernet technology. Examples of wireless connections comprise radio connections. Accordingly, in an example a connection between the crane and the interface 1114 may be a wireless radio link. The wireless radio link may be on a radio frequency band, for example a frequency band for industrial, scientific and medical (ISM) applications. Examples of the ISM bands comprise frequency bands at the frequency ranges of 419 MFIz, 429 MFIz, 434 MFIz, 447 MFIz, 458 MFIz, 868 MFIz, 869 MFIz, 915 MFIz and 2,4 GFIz. The wireless radio link may comprise one or more frequency channels for communications between the interface 1114 and the crane.

[0066] In an example in accordance with at least some embodiments, the interface 1114 to the control bus of the crane may be configured to operate as a relay between the lifting device and the control bus of the crane. In this way the data and/or commands may be carried over the link without modification of the content. In an example, the lifting device and the crane may be connected by a wireless radio link and interface 1114 may relay data and/or commands between the wireless radio link and the processing unit 1108. In this example, the wireless radio link may be a relay link, where at the crane, there is provided a relay node connected to the control bus of the crane and the relay node is configured to relay data and/or commands between the wireless radio link and the control bus of the crane.

[0067] In an example in accordance with at least some embodiments, the interface 1114 to the control bus of the crane is configured to connect to the control bus of the crane over a wireless radio link. The wireless radio link may be a relay link between the interface 1114 and the crane.

[0068] In an example in accordance with at least some embodiments, the interface 1114 to the control bus of the crane comprises at least two operation modes for interference mitigation on the wireless radio link. In this way data and/or commands may be reliably received at the lifting device via the wireless radio link. Examples of the operation modes may comprise a manual operation mode, a semi automatic operation mode and an automatic operation mode.

[0069] The manual operation mode may comprise that a frequency channel of the wireless radio link may be set manually by the user. In this way the user may set the frequency channel based on his/her knowledge of free frequency channels, or frequency channels where a level of interference is low.

[0070] The semi-automatic operation mode and automatic operation mode may comprise that the frequency channel of the wireless radio link may be set based on at least one of a search for a free frequency channel and a set of frequency channels. The automatic operation mode may require less settings from the user than the semi-automatic mode and/or one or more functionalities that may be performed without user input. For example, the automatic operation mode may comprise setting the frequency channel of the wireless radio link based on both the search for a free frequency channel and the set of frequency channels, where user input regarding the free frequency channel and/or a selection of the set of frequency channels may be at least partially omitted.

[0071] The free frequency channel may be searched from a set of frequency channels and once the free frequency channel has been found the free frequency channel may be set as the frequency channel of the wireless radio link. The interface 1114 may be configured to traverse the set of frequency channels and change the frequency channel used on the wireless radio link based on a predefined change pattern. Accordingly, the free frequency channel and subsequent frequency channels may be from the same set off frequency channels. In this way the first channel on the wireless radio link is free, whereby interference on the first channel is low, and later on as the frequency channels are traversed, the interference mitigation on the wireless radio link is supported by changing the frequency channel used on the wireless radio link based on a change pattern of the frequency channels. An example of the change pattern is that the frequency channels of the set are traversed in an increasing order or decreasing order of the frequency channels. The set of frequency channels may be a predefined set from more than one set of frequency channels, whereby the set that experiences, or is likely to experience, the least interference may be selected to be used on the wireless radio link. The predefined set of frequency channels may be configured to the interface 1114, whereby the frequency channel may be selected by the interface from the configured set. The selected frequency channel may be a predefined frequency channel, for example a frequency channel having the highest frequency or the frequency channel having the lowest frequency. The selected frequency channel may be changed to another frequency channel in the set, for example to a frequency channel on a higher frequency or to a frequency channel on a lower frequency, for supporting interference mitigation on the wireless radio link.

[0072] The automatic operation mode may comprise that the frequency channel of the wireless radio link may be set based on a search for a free frequency channel and a set of frequency channels without user input. The free frequency channel may be searched from a set of frequency channels and once the free frequency channel has been found the radio free frequency channel may be set as the frequency channel of the wireless radio link and the interface may be configured to traverse the set of frequency channels and change the frequency channel used on the wireless radio link based on a predefined change pattern. The set of frequency channels may be a predefined set from more than one set of frequency channels. An example of the change pattern is that the frequency channels of the set are traversed in an increasing order or decreasing order.

[0073] Additionally interface to crane control bus 1114 may provide connecting the lifting device to an electrical power supply of the crane such that operations of the lifting device may be powered by the crane. However, the connection to the electrical power supply of the crane may also be separate from the interface 114. The interface 1116 to claw wagons provides at least an electrical power supply to the electric actuators. The interface 1116 may be connected to the electrical power supply of the crane via the interface 1114, for example. Additionally, the interface 1116 to claw wagons provides one or more of communications of sensor information from the sensors and communications of control data for controlling the electric actuators. The interface 1116 to claw wagons may also provide status queries for the controller unit to request status information from the sensors. The interface 1116 to claw wagons may be implemented using a wired or wireless connection. Examples of the connections comprise field bus technologies such as CAN, Profibus, Scanbus or Ethernet connections.

[0074] The sensors may comprise one or more of binding wire sensors, locking mechanism sensors, landing sensors and gripping means sensors. Examples of the binding wire sensors, landing sensors, locking mechanism sensors and gripping means sensors comprise switches. A switch may be an electromagnetic switch, a mechanical switch or an electromechanical switch. The switch may be installed to the claw wagon, gripping means and/or the locking mechanism. When installed to the claw wagon and/or the gripping means the switch may be sensitive to at least one of a gripping position and a release position of the gripping means. When installed to the locking mechanism, the switch may be sensitive to an actuation of locking by the locking mechanism.

[0075] An example of the binding wire sensors comprise an inductive sensor configured to detect a presence of binding wires based on a change of magnetic field caused by the binding wire. A binding wire sensor may comprise a coil wound around a ferrite core. The binding wire sensor may generate a magnetic field and the binding wire sensor may be configured to detect a change of the magnetic field, when a metallic binding wire is brought into the magnetic field.

[0076] Further examples of the binding wire sensors comprise sensors based on optical detection technology, whereby also binding wires that do not caused a change in a magnetic field when brought into the magnetic field maybe detected. [0077] In an example in accordance with at least some embodiments, the controller unit 1102 of the lifting device comprises a memory 1112 storing instructions, that, when executed by the one or more processors 1110 of the controller unit, causes execution of a one or more functionalities described herein. The instructions may be computer readable program code means, computer program, computer instruction or computer code.

[0078] A memory may be a computer readable medium that may be non- transitory. The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, and processors based on multi-core processor architecture, as non-limiting examples.

[0079] Fig. 12 illustrates an example of gripping position and release position of gripping means in accordance with at least some embodiments of the present invention. The gripping means may be comprised in claw wagons of a lifting device for pulp units. Fig. 12 illustrates a gripping position in view Ί2A’ and a release position in view Ί2B’. The gripping position and release position are illustrated as seen from below the claw wagons 1202 of a lifting device. In Ί2A’, a pulp unit 1208 may be attached to the claw wagons 1202 by one or more binding wires 1206 that rest on the gripping means 1204 that are in the gripping position. In Ί2B’, a pulp unit 1208 is not attached to the claw wagons 1202 by the binding wires 1206 since the gripping means are in the release position and the binding wires are not positioned vertically above the gripping means. The gripping means are arranged on opposite sides of the claw wagon. The gripping means may be driven from a release position by electric actuators towards each other to reach the gripping position, where the gripping means are substantially parallel under the binding wires. In this way the binding wires may be safely kept resting on the gripping means, when the pulp units are lifted by the gripping means. From the gripping position the gripping means may be driven by electric actuators away from each other in order for the gripping means to reach the release position, where the gripping means are separated by a gap 1210. In the release position, binding wires gripped by the gripping means in the gripping position are released. Accordingly, when the gripping means are in the gripping position, the gap is closed, and escape of the binding wires is prevented.

[0080] In an example in accordance with at least some embodiments, a claw wagon 1202 comprises one or more binding wire sensors 1212 for detecting a presence of the binding wires. The number of the binding wire sensors may be more depending on the number of binding wires and type of binding wire sensors used. For example, the claw wagon may comprise sensors for each binding wire. The sensors may be positioned for example above the gripping means, whereby the in the gripping position, the binding wire is brought by the gripping means at a controlled distance from the binding wire sensor for detecting presence of the binding wire.

[0081] Fig. 13 illustrates an example of a method for a lifting device in accordance with at least some embodiments of the present invention. The method provides safety in handling pulp units. The method may be performed by a lifting device comprising one or more claw wagons and the claw wagons comprising gripping means operatively connected to electric actuators for gripping and releasing pulp units by the gripping means. The controller unit is configured to connect to a control bus of a crane and said controller unit is connected to the electric actuators of the claw wagons and arranged to perform one or more phases of the method.

[0082] Phase 1302 comprises determining landing information for one or more claw wagons. The landing information provides determining whether all of the claw wagons have been landed on pulp units or not, or whether one or more given claw wagons have been landed on pulp units or not.

[0083] Phase 1304 comprises controlling at least one claw wagon on the basis of the determined landing information. In this way, claw wagons that have been landed may be controlled for gripping or releasing pulp units by gripping means and control of claw wagons that have not been landed may be omitted.

[0084] In an example phase 1302 comprises receiving information indicating that one or more of the claw wagons have been landed. The information may be received from landing sensors installed to the claw wagons. A landing sensor may be triggered, when a claw wagon has been landed on a pulp unit, whereby the landing sensor may send information indicating that the claw wagon has been landed. A landing sensor installed to the claw wagon may be triggered in response to a claw wagon touching the pulp unit below the claw wagon. In this situation at least part of the weight of the claw wagon, or the whole weight of the claw wagon, may be supported by the pulp unit.

[0085] In an example phase 1304 comprises that the determined landing information indicates which of the claw wagons have been landed on pulp units, and the claw wagons that have been landed are controlled for gripping or releasing pulp units by gripping means of the claw wagons. Therefore, the claw wagons that have not been landed are not controlled for gripping or releasing pulp units, whereby safe operation of the lifting device is supported.

[0086] In an example phase 1302 comprises that a crane is sent information indicating the determined landing information, whereby the crane may determine which of the gripping means may be controlled on the basis of the landing information. The crane may determine to control the gripping means of the claw wagons that have been landed, whereby the crane may send a control command via the control bus to the lifting device for gripping or releasing pulp units by the gripping means of the landed claw wagons. [0087] In an example, phase 1304 comprises that the lifting device may determine on the basis of the landing information which of the gripping means may be controlled. Then, when the lifting device receives a control command from the control bus of the crane, to control one or more claw wagons for gripping or releasing pulp units by the gripping means of the claw wagons, the lifting device may control only those gripping means of the claw wagons that have been landed. On the other hand if a control command concerns controlling more than one claw wagon, the control command may be ignored by the lifting device, if any of the claw wagons has not been landed. A message, e.g. a fault message may be sent to the crane, if execution of the control command cannot be performed or if the control command is executed only partially.

[0088] In an example in accordance with at least some embodiments, a crane comprises a crane control bus connected to a lifting device for pulp units. The crane comprises a controller unit connected to the crane control bus for controlling the lifting device. The crane may be configured to generate one or more control commands for controlling one or more claw wagons of a lifting device. The generated one or more control commands may comprise at least one control command for controlling at least one claw wagon, more than one claw wagon, at least one pair of the claw wagons, a part of the claw wagons or all of the claw wagons for gripping or releasing pulp units by the gripping means of the controlled at least one claw wagon, more than one claw wagon, at least one pair of the claw wagons, a part of the claw wagons or all of the claw wagons. The one or more control commands may be generated at the crane based on one or more user interface actions, based on semi-automated cargo handling operation of the crane and/or based on automated cargo handling operation of the crane. Examples of the semi-automated and automated cargo handling operations of the crane comprises cargo handling operations, where computerized systems, for example machine- vision, are employed to reduce a need for manual control in cargo handling. Accordingly, the one or more control commands need not to be directly generated based on manual cargo handling operation performed by user, but it is viable that the one or more control commands are generated by a software routine configured to execute a semi-automated or an automated cargo handling operation, e.g. in this example gripping pulp units or releasing pulp units. Examples of the user interface actions comprise user input received by a joystick and/or touch screen that may be operatively connected to the controller unit. The generated one or more control commands may be transmitted over a wireless connection or a wired connection to the lifting device, for example by relaying the generated one or more control commands by a transmitter node at the crane to an interface at the lifting device. [0089] It should be appreciated that controlling gripping means may refer to controlling a claw wagon comprising the gripping means. On the other hand, controlling the claw wagon may refer to controlling gripping means of the claw wagon.

[0090] In an example in accordance with at least some embodiments of the present invention, a crane comprises a crane control bus connected to a lifting device for pulp units. The lifting device comprises one or more claw wagons, said claw wagons comprising gripping means operatively connected to electric actuators for gripping and releasing pulp units by the gripping means, a controller unit configured to connect to the control bus of the crane and said controller unit being connected to the electric actuators of the claw wagons, and the controller unit is arranged to: in response to receiving at least one control command from the control bus of the crane, to control at least one claw wagon for gripping or releasing pulp units by the gripping means of the at least one claw wagon. In this way load handling of the pulp units is provided without a hydraulic system driving the gripping means. This is particularly beneficial in cranes that have electric drive systems or in cranes that have hybrid drive systems.

[0091] It should be appreciated that controller unit of the crane may comprise a memory storing instructions, that, when executed by the one or more processors of the controller unit, causes execution of a one or more functionalities described herein.

[0092] It will be obvious to one skilled in the art that in the development of technology the basic idea of the invention can be implemented in many different ways. Thus, the invention and its embodiments are restricted to the examples described above but can vary within the scope of the claims. List of reference signs

102 Crane

104 Lifting device for pulp units 106 Pulp units 107 Gripping means

108 Strapping wire 110 Claw wagon 112 Load handling area 114 Controller unit 202 Load handling area

204 to 210 Configurations for storing pulp units in a load handling area

304 Lifting device for pulp units

305 End side 306 Claw wagon

308 Electric actuator 310 Main beam 312 Cross-beam 314 Gripping means 315 Locking mechanism

316 Gear 700 Lifting device 702 Claw wagon 704 Row of pulp units 706 Pulp unit 710 Beam

712 Beam

802, 804 Phases of the method of Fig. 8 902 to 918 Phase of the method of Fig. 9 1002 to 1008 Phase of the method of Fig. 10

1102 Controller unit 1106 Electric actuator 1108 Processing unit 1110 Processor 1112 Memory 1114 Interface to crane control bus 1116 Interface to claw wagons

1118 to 1128 Sensors 1202 Claw wagon 1204 Gripping means

1206 Binding wire 1208 Pulp unit 1210 Gap 1212 Binding wire sensor 1302 and 1304 Phases of Fig. 13