Mobile cranes

Abstract

An embodiment is directed to a mobile crane having an articulated body and an elongated boom attached to the body for carrying a load when the crane is stationary and when the crane is moving, the boom being articulated to provide movement for raising and lowering an end of the boom, wherein the boom is further articulated to provide movement of the boom laterally. Another embodiment is directed to controlling the swing of a load carried at an end of a boom of a mobile crane by changing the lateral orientation of the boom.

Description

Technical Field

[0001] Embodiments relate to a pick and carry crane having an articulated boom. Background Art

[0002] A picking crane is a crane that is able to move (i.e., travel) while having a load suspended from the boom of the crane. Some picking cranes are capable of traveling at high speeds on public roads, where they are classified as special purpose vehicles. The design of a picking crane can vary depending on the application of the crane. Certain designs of picking cranes are easier to operate than other crane types. For example, when the picking crane is an articulated crane, the entire crane can fit within the turning circle of the crane. This design feature can enable an articulated picking crane to be used in confined or tight spaces, such as to lift and move loads on the floor of a production facility.

[0003] Picking cranes can also take the form of a "taxi crane", i.e. a crane that travels with all the equipment required to operate the crane within the full capabilities of the crane. Many cranes cannot be operated as taxi cranes because they cannot transport all the components required for operation, so a support vehicle is usually required to carry additional components such as counterweight and rigging (including slings and hooks).

[0004] Typically, in a picking crane, the same operator station is used to control the crane both when traveling (such as on a public road) and when operating the crane in a facility. This "single cabin" arrangement helps simplify the crane configuration and provides flexibility to the operator (i.e., not having to move back and forth between the driver's cabin and the crane cabin).

[0005] The tipping line of such a picking crane is defined by the contact point between the crane and the ground (i.e., the tires). Therefore, when the moment about the tipping line is sufficient, the crane will tip or fall about the tipping line. There are many factors that affect the magnitude of the moment about the tipping line ("tipping moment"), such as boom extension, boom luff, load weight and weight distribution, the slope of the ground and the orientation of the crane relative to that slope, the extent of the crane articulation, the sway of the load, etc.

[0006] Since order picking cranes are often sized to fit on public roads, tipping over can be a significant problem. Tipping over of a crane not only damages the crane, but also poses a significant safety concern to the operator of the tipping crane and anyone nearby who may be put in danger by the tipping crane.

[0007] For other mobile cranes, outriggers may be used to minimize the possibility of a sideways tipping. However, such outriggers are used when the crane is operating in a stationary position. As order picking cranes need to travel with a load, this means that outriggers cannot usually be used.

[0008] It should be understood that reference to prior art herein does not constitute an admission that such art forms part of the common general knowledge of a person skilled in the art in Australia or any other country. Summary of the invention

[0009] Embodiments relate to a mobile crane. The mobile crane may be a taxi crane. The mobile crane may be a picking crane for operation on public roads. The mobile crane may not have outriggers. The mobile crane may be articulated. The mobile crane may have a single operator cabin for controlling the crane while traveling and for controlling the crane while lifting and / or moving a load.

[0010] One embodiment relates to a mobile crane having an articulated body and an elongated boom attached to the body, the boom for carrying a load when the crane is stationary and when the crane is moving, the boom being articulated to provide movement of an end of the boom for lifting and lowering, wherein the boom is further articulated to provide movement of the boom laterally. The movement for lifting and lowering may provide a first degree of freedom for the movement of the boom. The movement for lifting and lowering may be articulated up and down. The lateral movement may provide a second degree of freedom for the movement of the boom. The lateral movement may be articulated laterally.

[0011] In one embodiment, the boom may be articulated about a first axis substantially perpendicular to the longitudinal axis of the crane. Such articulation may correspond to up-and-down articulation. The boom may further be articulated about an axis substantially parallel to the longitudinal axis of the crane. Such articulation may correspond to lateral articulation.

[0012] The mobile crane may have a first articulated joint for providing lifting and lowering movement and a second articulated joint for providing lateral movement.

[0013] The mobile crane may have an actuator for providing lifting and lowering movement as well as lateral movement. The actuator may be mechanical, pneumatic, hydraulic, electrical or any combination thereof.

[0014] The actuator may include two plungers, wherein the plungers move to provide lifting and lowering movement and / or lateral movement.

[0015] The two plungers may move in the same direction to provide lifting and lowering movement, and wherein the two plungers move in the same direction at different speeds or in opposite directions to provide lateral movement.

[0016] The plungers may be hydraulic plungers.

[0017] In one embodiment, the two plungers are arranged symmetrically with respect to the boom and the body of the crane.

[0018] In an alternative embodiment, the actuator may include two plungers that are asymmetrically arranged relative to the boom and the body of the crane. The first plunger may be movable to provide movement for raising and lowering the end of the boom. The second plunger may be movable to provide movement of the boom laterally. When the boom is only raised and lowered, the second plunger may be stationary. When the boom is only moved laterally, the first plunger may be stationary.

[0019] According to this embodiment, the control for lifting with the first plunger can be independent of the control for lateral movement with the second plunger, thus making it potentially simpler to control each movement independently, with only one plunger being used for each movement. Other potential advantages can be that the second plunger is positioned on one side of the boom (laterally), thereby leaving space for a side cabin on the other side. The first plunger can still be placed below the boom. This can also allow the boom to be lowered to a level below the height of the cabin.

[0020] The first plunger may be attached to the boom at the midline of the boom.The second plunger may be attached to the boom on one side of the boom.

[0021] Another embodiment is directed to a method of controlling a mobile crane having an articulated body and an elongated boom attached to the body for carrying a load when the crane is stationary and when the crane is moving, the method comprising moving the boom to raise and lower an end of the boom and to move the boom laterally. The movement for raising and lowering may provide a first degree of freedom for the movement of the boom. The lateral movement may provide a second degree of freedom for the movement of the boom.

[0022] The crane may comprise a first articulated joint for providing lifting and lowering movement and a second articulated joint for providing lateral movement.

[0023] The lifting and lowering movement and / or the lateral movement may be provided by an actuator. The actuator may be mechanical, pneumatic, hydraulic, electric or any combination thereof.

[0024] When the actuator includes two plungers, the method may include moving the plungers to provide the lifting and lowering movement as well as the lateral movement.

[0025] The method may include moving the plungers in the same direction to provide lifting and lowering movement, and moving the two plungers in the same direction at different speeds or in opposite directions to provide lateral movement.

[0026] Another embodiment is directed to a method of controlling a tipping moment of a mobile crane having an articulated body and an elongated boom attached to the body for carrying a load when the crane is stationary and when the crane is moving, the method comprising moving the boom laterally.

[0027] The method may further include raising or lowering the boom to control the tipping moment.

[0028] The boom can be raised or lowered while moving the boom laterally.

[0029] The boom may be raised or lowered before or after moving the boom laterally.

[0030] Another embodiment is directed to a method of controlling the sway of a load supported by a mobile crane having an articulated body and an elongated boom attached to the body for carrying the load when the crane is stationary and when the crane is moving, the method comprising moving the boom laterally in response to the sway.

[0031] The method may include measuring a sway of the load and laterally moving the boom in accordance with the measured sway.

[0032] The method for measuring sway can be done by radar sensors to scan the load in three dimensions or by motion sensors to sense the dynamic motion and acceleration of the crane, boom, hook attachment / load. The boom will then be moved to counteract the momentum of the swaying load, cancelling the swaying motion. This can be calculated from the known position and acceleration of the load and the known weight of the crane and the weight of the load mass, where the crane measures the load mass through pressure sensors in the hydraulic rams that lift the boom. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Here, embodiments are described with reference to the accompanying drawings, in which:

[0034] Figure 1 A perspective view of an embodiment of a picking crane is shown;

[0035] Figure 2 A side view of a picking crane is shown;

[0036] Figure 3 and Figure 4 A top view of a picking crane is shown;

[0037] Figures 5 to 8 An articulated joint connecting the boom to the front body of the order picking crane is shown;

[0038] Fig. 9 The lateral articulation of the boom of a picking crane is shown;

[0039] Fig.10 is a schematic diagram showing a portion of a control system for a boom of a picking crane; and

[0040] Figures 11A to 11D An alternative embodiment of a picker crane is shown. DETAILED DESCRIPTION

[0041] Figure 1 , Figure 2 and Figure 3 A picking crane 10 is shown. The crane 10 has a front body 12, which is the front part of the crane 10. The front body 12 is pivoted by a pivot device 30 ( Figure 2 and Figure 3 The front body 12 and the rear body 14 are pivotally connected to each other (illustrated by dashed lines in FIG. 1 ). A movable linkage mechanism (a hydraulic ram in this example, but other linkage mechanisms are also known) is provided at the pivot point 30 to control the pivot angle of the front body 12 and the rear body 14. Using a movable linkage mechanism to adjust the pivot angle facilitates the rotation of the crane 10.

[0042] When the front body 12 pivots relative to the rear body 14, a rollover line 34 is defined (see Figure 4 ).

[0043] In the embodiment of the order picking crane 10 as shown in the figures, the rollover line 34 is an imaginary longitudinal axis extending between the point where the outer tires T1 of the front body contact the ground via wheels 20 and the point where the outer tires T3 of the rear body contact the ground via wheels 18. Thus, the tires T1 and T3 of wheels 20 and 18 define the point about which the crane may roll sideways. The crane 10 includes two sets of rear tires T3 and T2. In this embodiment, the frontmost set of tires T3 is used to define the rollover line because the rearmost set of tires T2 can be lifted in the gliding mode so that these tires are no longer in contact with the road or other driving surface.

[0044] The illustrated order picking crane has three axles, but it will be appreciated that in different embodiments the mobile crane may have two axles or more than three axles.

[0045] Attached to the rear end of the front body 12 is a boom support arm 24. The boom support arm 24 may be a separate structure that is mounted (e.g., welded or bolted) to the front body 12. In one embodiment, the boom support arm 24 forms part of the chassis of the front body 12. The boom support arm 24 pivotally supports a boom 26 that pivots around a pin 27 ( Figure 2 ) indicates the pivot point rises and falls. The boom 26 is retractable. Other forms of linear actuators and booms may be used to replace or supplement the plunger 28 and the boom 26.

[0046] Figure 5 The joint between the boom 26 and the boom support arm 24 is shown. The embodiment employs boom articulation, which allows the boom to be articulated up and down as well as side to side. Figure 5 In the illustrated embodiment, the double articulated joint 40 provides two forms of articulation.

[0047] Figure 6 A top view of a plate 42 for use in an articulated joint 40 is shown.

[0048] Figure 7 The bottom side of the plate 42 is shown and how the plate 42 engages with the hanger rod 26. The plate 42 is provided with brackets 52, 54, 60 and 62 on the upper surface, and corresponding circular voids 56, 58, 64 and 66 are formed in the brackets 52, 54, 60 and 62. Figure 7 As shown, brackets 70 and 72 are provided on the lower surface of the plate 42, and circular voids 74 and 76 are formed in the brackets 70 and 72.

[0049] Two pins 80 and 82 are provided on the underside of the boom 26. In use, the pins 80 and 82 of the boom 26 engage the gaps 56, 58, 64 and 66 of the brackets 52, 54, 60 and 62 of the plate 42. The pins 80 and 82 enable the boom to pivot up and down relative to the plate 42.

[0050] like Figure 8 As shown, the boom support arm 24 is provided with plates 130, 132, 134 and 136, and corresponding gaps ( Figure 8 Only the gap 138 in plate 130 and the gap 140 in plate 134 are visible. Pins 90 and 94 engage with the gaps formed in plates 130, 132, 134 and 126. Lower brackets 70 and 72 of plate 42 engage with pins 90 and 94 provided on boom support arm 24 ( Figure 6 ). This joint then enables the plate 42 to pivot transversely (relative to the longitudinal axis of the boom 26). The boom 26 is thereby able to pivot transversely.

[0051] like Figure 5 As shown, the plate 42 is received in the recess 92 of the boom support arm 24, and the size of the recess corresponds to the size of the plate 42, so that the amount of lateral movement of the boom is limited. In this embodiment, the lateral movement of the boom 26 is limited to 5° on either side of the vertical line, so that the total lateral movement of the boom is limited to 10°.

[0052] In an alternative embodiment, the total lateral movement of the boom is limited to 20°, 10° on either side of the vertical.

[0053] Fig. 9 Lateral articulation of the boom 26 at an angle α is shown. As shown, the order picking crane 12 is shown here on inclined terrain G at an angle θ relative to the horizon. The slope of the terrain G will move the center of gravity away from the center of the order picking crane, thereby increasing the tipping moment and thus destabilizing the crane. By laterally articulating the boom 26 as shown, the center of gravity is directed back toward the center of the crane, thereby reducing the tipping moment and potentially improving stability.

[0054] In alternative embodiments, the degree of lateral movement may be set based on a number of factors, such as the maximum length of the boom when extended, the capabilities of the crane, operating conditions, etc.

[0055] Hydraulic rams 28A and 28B control both the up and down articulation of boom 26 and also the lateral articulation. For certain embodiments, it may be advantageous to use hydraulic rams to control both the up and down and lateral articulation because known order picking cranes include such hydraulic rams. Thus, there is no need to develop and install a new articulation mechanism to accommodate lateral articulation on the basis of the existing up and down articulation.

[0056] Fig. 9 A control system 106 is shown for controlling the articulation of the boom 26. The control system 106 is connected to two directional control valves 102A and 102B, which are connected to respective hydraulic rams 28A and 28B. An oil supply 104 is connected to the directional control valves 102A and 102B. This provides oil used as the hydraulic fluid in the system.

[0057] By controlling the directional control valves 102A and 102B, the control system 106 controls the movement of the plungers 28A and 28B, thereby controlling the articulation of the boom 26. By moving the plungers in the same direction at the same time and at the same speed, the boom 26 will only articulate upward or downward. The control system 106 can control the lateral articulation of the boom 26 by moving only one of the plungers, or by moving the two plungers at different speeds or in different directions.

[0058] The control system is also connected to a mode selector 108 whereby the user selects the mode of the crane as either manual or automatic, and to a command input 110 which the user can use to control the boom. Various sensors are also connected to the control system: a boom lateral angle sensor 112; a chassis angle sensor 114; a wheel speed sensor 116; and an engine RPM sensor 118.

[0059] The control system 106 uses input from operator input and sensors to control the boom lateral angle. For example, if the mode selector is in automatic mode and the chassis angle sensor detects tilt, the control system will tilt the boom laterally in the opposite direction to compensate for the tilt in the chassis.

[0060] It should be appreciated that other sensors may additionally be used. For example, boom extension sensors; boom up and down articulation sensors; crane articulation sensors; load height sensors; load sway sensors, etc. The extent to which the boom is laterally articulated will take all of these factors into account to potentially improve crane stability.

[0061] Figures 11A to 11D A portion of a picking crane according to an alternative embodiment is shown. Similar reference numerals are used to denote similar features. Figures 1 to 10 The same as the example, Figures 11A to 11D The embodiment shown in includes a boom support arm 24 attached to a boom 126 via a base plate 142. The connection point provides two articulation axes so that the boom 26 can move up and down and sideways relative to the body of the crane.

[0062] Figures 1 to 10 The embodiment shown in FIG. 1 has two hydraulic rams 28A and 28B attached to the lateral sides of the boom 26 and arranged symmetrically with respect to the boom 26. Figures 11A to 11D In the embodiment of FIG. 1 , two plungers 128A and 128B are attached between the hanger 126 and the base plate 142, wherein the plunger 128A is attached to the hanger at the midline 130 ( Fig. 11C ), and the boom 128B is attached to the side of the boom at point 132.

[0063] Thus, plungers 128A and 128B are asymmetrically attached between the boom 126 and the base plate 142. Thus, up and down movement of the boom 126 is controlled by plunger 128A, and lateral movement of the boom 126 is controlled by plunger 128B.

[0064] Fig.11A and 11B Different configurations of the mobile crane are shown when the boom 128A is activated. Fig.11A The boom 126 is shown in a lowered position, while Fig. 11BThe boom is shown in the raised position, movement between these two configurations being accomplished by actuating plunger 128A.

[0065] Fig. 11C The configuration of the boom 126 on the left side (in the direction of travel) is shown, while Fig.11D The configuration of the boom 126 is shown on the right side. By activating the plunger 128B, the boom is Fig. 11C and 11D to move between configurations.

[0066] It will be appreciated that plungers 128A and 128B need not be activated independently; they may be activated together to move the boom up and down and side to side simultaneously. Fig.10 The above control system shown in FIG. is also applicable to Figures 11A to 11D Embodiment of the invention.

[0067] Another embodiment involves controlling the sway of the load. In this embodiment, the operator controls the lateral articulation of the boom to reduce or stop the sway of the load. By timing the lateral articulation of the boom, the operator is able to suppress the sway of the load, which can improve the stability of the crane, as sway of the load can cause the crane to tip over.

[0068] To determine sway, various measurements are taken of the position of the load relative to the boom. These measurements are taken using radar sensors, scanning the load in 3D, or they are taken by motion sensors, sensing the dynamic movement and acceleration of the crane, boom, hook attachment / load.

[0069] The boom is then moved to counteract the momentum of the swinging load, canceling the swinging movement. The amount of movement required can be calculated from the known position and acceleration of the load and the known weight of the crane and the mass of the load, which is measured by the crane through pressure sensors in the hydraulic rams that lift the boom.

[0070] Features of order picking cranes related to the control of tipping are described in PCT / AU2014 / 000261, PCT / AU2017 / 050999 and AU2018903904, the contents of which are incorporated herein. It should be appreciated that the lateral articulation of the boom described herein can incorporate the anti-tip considerations and controls discussed in these applications.

Claims

1. A mobile crane (10) having an articulated body (12) and an elongated boom (26) attached to the body, the boom being used to carry a load when the crane is stationary and when the crane is moving, the boom being articulated to provide movement for raising and lowering an end of the boom, wherein: The boom is further articulated to provide lateral movement of the boom, The mobile crane also includes an actuator for providing lifting and lowering movement and lateral movement, the actuator comprising two plungers (28A, 28B), wherein the plunger moves to provide the lifting and lowering movement and the lateral movement, characterized in that The two plungers move in the same direction to provide the lifting and lowering movement, and wherein the two plungers move in the same direction at different speeds or in opposite directions to provide the lateral movement.

2. A mobile crane according to claim 1, having a first articulated joint for providing lifting and lowering movement and a second articulated joint for providing lateral movement.

3. The mobile crane according to claim 1 or 2, wherein: The plungers (28A, 28B) are arranged symmetrically with respect to the boom and the body of the crane.

4. A mobile crane having an articulated body and an elongated boom (126) attached to the body, the boom being used to carry a load when the crane is stationary and when the crane is moving, the boom being articulated to provide movement for raising and lowering an end of the boom, wherein: The boom is further articulated to provide lateral movement of the boom, The mobile crane further comprises an actuator for providing the lifting and lowering movement as well as the lateral movement, characterized in that The actuator is composed of a first plunger (128A) and a second plunger (128B), the first plunger and the second plunger being arranged asymmetrically with respect to the boom and the body of the crane, wherein the first plunger (128A) moves to provide movement for raising and lowering the end of the boom, and Wherein, the second plunger (128B) moves to provide lateral movement of the boom.

5. The mobile crane according to claim 4, wherein: The first plunger (128A) is attached to the boom at a midline of the boom.

6. The mobile crane according to claim 4 or 5, wherein: The second plunger (128B) is attached to the boom on one side of the boom.

7. A mobile crane according to any preceding claim, wherein: The plunger is a hydraulic plunger.

8. A method of controlling a mobile crane (10) having an articulated body (12) and an elongated boom (26) attached to the body, the boom being used to carry a load when the crane is stationary and when the crane is moving, the method comprising moving the boom to raise and lower an end of the boom and to move the boom laterally, the boom being articulated to provide movement for raising and lowering the end of the boom, wherein The boom is further articulated to provide lateral movement of the boom, The mobile crane also includes an actuator for providing lifting and lowering movement and lateral movement, the actuator comprising two plungers (28A, 28B), wherein the plunger moves to provide the lifting and lowering movement and the lateral movement, characterized in that The method includes moving the two plungers in the same direction to provide the lifting and lowering movement, and moving the two plungers in the same direction at different speeds or in opposite directions to provide the lateral movement.

9. A method of controlling a mobile crane having an articulated body and an elongated boom attached to the body for carrying a load when the crane is stationary and when the crane is moving, the method comprising moving the boom to raise and lower the ends of the boom and to move the boom laterally, wherein: The boom is articulated to provide movement for raising and lowering an end of the boom, wherein the boom is further articulated to provide lateral movement of the boom, The mobile crane further comprises an actuator for providing the lifting and lowering movement as well as the lateral movement, characterized in that The actuator is composed of a first plunger (128A) and a second plunger (128B), the first plunger and the second plunger being arranged asymmetrically with respect to the boom and the body of the crane, wherein the method further comprises moving the first plunger (128A) to provide movement for raising and lowering the end of the boom, and The second plunger (128B) is moved to provide lateral movement of the boom.

10. The method according to claim 9, wherein: The mobile crane comprises a first articulated joint for providing lifting and lowering movement and a second articulated joint for providing lateral movement.

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