AU2019100317A4 - An articulated pick and carry crane - Google Patents

Abstract

An articulated pick and carry crane includes a chassis including a front chassis portion and a rear chassis portion, a pivotal connection between the front chassis portion and rear chassis portion, a steering system configured to rotate the front chassis portion relative to the rear chassis portion about the pivotal connection, and a steering control device, configured to control at least one operating characteristic of the steering system. A load management device is provided, configured to determine a current load moment of the crane, determine whether the current load moment meets a warning condition, and control the steering control device to restrict rotation about the pivotal connection in a direction that would increase the load moment when the current load moment meets the warning condition. FIG. 1-2 11°-20° 11°-20° 10°0-10° 21°-42° 21°-42°

Description

AN ARTICULATED PICK AND CARRY CRANE

2019100317 26 Mar 2019

STATEMENT OF CORRESPONDING APPLICATIONS

This application is based on the specification filed in relation to New Zealand Patent Application No.

741038, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to articulated pick and carry cranes, and more particularly systems and methods for resisting further steering of an articulated pick and carry crane when articulating in a worsening load moment direction.

BACKGROUND

Traditionally, cranes have generally not been considered susceptible to steering issues, as the crane functionality is not used while the vehicle moves. In most cases the vehicle is effectively an inbuilt carrier unit, used to transport the crane between job sites with the boom of the crane in a retracted and fixed position. In order to increase stability while stationary, support structures such as outriggers may be deployed in order to widen the base. However, the applicant has identified that cranes designed to pick up a load, and move with it (known as pick and carry cranes), may be especially vulnerable to safety issues associated with steering of such vehicles.

One configuration of pick and carry cranes utilises articulation of the chassis to effect steering. Articulation of the crane enables a tighter turning circle, which is highly important in order for manoeuvring the crane within relatively restricted areas. Further, articulation enables slewing of the boom to assist in placement of a load being carried by the boom. However, this articulated configuration has some disadvantages from a safety perspective - particularly with regard to susceptibility to rolling. Articulated pick and carry cranes generally have a relatively high ratio of weight to wheel base in order to achieve a desirable load capacity while minimizing size, making them more vulnerable to overturning.

Even relatively minor injury to the operator, or damage to the vehicle, resulting from overturning may lead to expenses and loss in operative capabilities which would preferably be avoided.

JAWs ref: 308853AU

2019100317 26 Mar 2019

It is an object of the present invention to address at least one of the foregoing problems or at least to provide the public with a useful choice.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The 5 discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

Unless the context clearly requires otherwise, throughout the description and the claims, the words comprise, comprising, and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of including, but not limited to.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

SUMMARY

According to one aspect of the present disclosure there is provided an articulated pick and carry crane, including:

a chassis including a front chassis portion and a rear chassis portion;

a pivotal connection between the front chassis portion and rear chassis portion;

a steering system configured to rotate the front chassis portion relative to the rear chassis portion about the pivotal connection;

a steering control device, configured to control at least one operating characteristic of the steering system;

a load management device, configured to:

determine a current load moment of the crane;

determine whether the current load moment meets a warning condition;

control the steering control device to restrict rotation about the pivotal connection in a direction that would increase the load moment when the current load moment meets the

JAWs ref: 308853AU

2019100317 26 Mar 2019 warning condition.

A steering control system for an articulated pick and carry crane having a steering system configured to rotate a front chassis portion relative to a rear chassis portion about a pivotal connection, the steering control system including:

a steering control device, configured to control at least one operating characteristic of the steering system;

a load management device, configured to:

determine a current load moment of the crane;

determine whether the current load moment meets a warning condition;

control the steering control device to restrict rotation about the pivotal connection in a direction that would increase the load moment when the current load moment meets the warning condition.

According to one aspect of the present disclosure there is provided a method of controlling an articulated pick and carry crane having a pivotal connection between a front chassis portion and a rear 5 chassis portion, the method including:

determining a current load moment of the crane;

determining whether the current load moment meets a warning condition;

controlling steering of the crane to restrict rotation about the pivotal connection in a direction that would increase the load moment when the current load moment meets the warning condition.

Reference to restricting rotation about the pivotal connection - i.e. steering of the articulated pick and carry crane - should be understood to encompass embodiments in which steering is still possible in that direction, but limitations are imparted to the steering by way of one or more of: increased resistance to operator steering (i.e. a heavier steering feel), and reduced steering speed.

It is envisaged that this may reduce the ease of exaggerating the risk by continuing to steer in the same direction, but still allow for a degree of control when steering in that direction. Further, embodiments in which the operator experiences a heavier steering feel provides physical feedback to the operator as to the presence of the warning condition. It is also envisaged that reducing the steering speed may reduce the potential of a pendulum effect occurring on a hanging load, which might otherwise produce a greater load moment with an associated increased risk of overturning the crane.

JAWs ref: 308853AU

2019100317 26 Mar 2019

In an exemplary embodiment the steering system may include at least one steering actuator connected between the front chassis portion and the rear chassis portion, wherein the steering actuator is configured to rotate the front chassis portion relative to the rear chassis portion about the pivotal connection. In an exemplary embodiment the at least one steering actuator may be a linear actuator.

For example, the linear actuator may be a hydraulic cylinder. Reference will herein be made throughout the specification to the steering actuator being a hydraulic cylinder, however is should be appreciated that other actuator types - for example, electric or pneumatic - may be used in exemplary embodiments of the present disclosure.

In an exemplary embodiment the steering control device may include at least one controllable valve associated with one or more actuators of the steering system. In an exemplary embodiment the steering control device may include a first controllable valve associated with a left steering actuator, and a second controllable valve associated with a right steering actuator. The controllable valves may be controlled by the load management device, such that steering in a direction which improves the load moment is less restricted (i.e. easier and/or faster) than in the opposite direction. For example, the load management device may at least partially close the at least one controllable valve to restrict flow of hydraulic fluid to a hydraulic steering actuator to restrict rotation about the pivotal connection in the direction that would increase the load moment when the current load moment meets the warning condition. It should be appreciated that reference to closing of the controllable valve may include partial closing of the valve, unless explicitly stated to the contrary.

!0 In an exemplary embodiment, the load management device may be configured to selectively operate in one of a crane mode, and a travel mode. In an exemplary embodiment, the load management device may be configured to not restrict steering while in the travel mode - i.e. the load management device is configured to only control the steering control device to restrict rotation about the pivotal connection while in the crane mode.

In an exemplary embodiment, the load management device may be configured to not restrict steering while the crane is travelling above a predetermined ground speed. It is envisaged that the steering restriction may not be implemented above a predetermined margin beyond an upper speed for the crane mode. By way of example, where a crane mode restricts speed to 10 kph, a 5 kph tolerance may be permitted (i.e. a threshold of 15 kph) to allow for machine speed overrun without unintentionally activating the steering restriction of the present disclosure. It is also envisaged that this may reduce the potential for the steering restriction being activated while already travelling at higher speeds.

In an exemplary embodiment, the load management device may receive a signal indicative of speed from an external source - for example, a location tracking device in the form of a GPS unit to enable

JAWs ref: 308853AU

2019100317 26 Mar 2019 location tracking and thus determination of ground speed, or at least one sensor associated with the powertrain of the crane, as known in the art. A function of the powertrain - such as transmission RPM

- may be detected, and other factors such as gear ratio and wheel size used to determine speed.

In an exemplary embodiment the steering control device may have a default configuration in which steering is not restricted - i.e. it must be actively controlled by the load management device to restrict steering. For example, where the steering control device includes a controllable valve, the valve may be biased towards an open condition. Restriction of steering may require control of the valve to overcome the bias to close the valve. It is envisaged that this may reduce the likelihood of the steering being restricted except when required.

It should be appreciated that reference to the various components being associated with the chassis is intended to encompass embodiments in which the components are not attached directly to the chassis per se, but may, for example, be attached to a secondary frame and/or additional components which are in turn attached to the chassis.

In an exemplary embodiment, a crane boom of the crane may be associated with the front chassis portion. It should be appreciated that the crane will include components associated with the boom in order used to perform the various craning functions - for example the lift cylinder or cylinders used to control the angle of the boom, and hoist for lifting and lowering of the load.

In an exemplary embodiment, the load management device may communicate with one or more sensors configured to determine a condition of the crane relevant to determination of the load !0 moment.

In an exemplary embodiment the crane may include a steering angle sensor configured to output a signal indicative of the angle of the front chassis portion relative to the rear chassis portion. Such a steering angle sensor may be any suitable sensor known to a person skilled in the art. For example, in an exemplary embodiment, at least one hydraulic cylinder controllable to articulate the crane may 25 include a sensor (for example, a magnetostrictive linear position sensor) configured to output a signal indicative of the current extension of the cylinder, and thereby angle of articulation. In another exemplary embodiment the steering angle sensor may be a rotary angle sensor, for example a Hall Effect rotary encoder. In a further exemplary embodiment, the sensor may be a proximity sensor configured to output a signal when a particular angle, or extension of the steering actuator, is achieved.

Such a proximity sensor may be either contact or non-contact.

Sensors relevant to determination of load moment may include: boom sensors (for example determining one or more of: boom extension, boom angle, mass of suspended load), load sensors,

JAWs ref: 308853AU

2019100317 26 Mar 2019 incline or tilt sensors, or any other sensor known in the art of load moment determination.

In an exemplary embodiment an operator input device may be provided for control of the steering system. For example, the operator input device may include a hydraulic or electrohydraulic steering unit configured to output a signal responsive to manual input by the operator. It is envisaged that the 5 hydraulic or electrohydraulic steering unit may provide physical feedback to the operator based on hydraulic fluid flow between the various components of the steering system.

However, it should be appreciated that other steering input arrangements are contemplated. For example, the operator input device may be an electronic steering input device, configured to output an electronic control signal to control elements of the steering system. In an exemplary embodiment, the 0 electronic steering input device may include force feedback functionality - more particularly configured to increase resistance to movement of the steering input device in the direction that would increase the load moment.

For a firmware and/or software (also known as a computer program) implementation, the techniques of the present disclosure may be implemented as instructions (for example, procedures, functions, and 5 so on) that perform the functions described. It should be appreciated that the present disclosure is not described with reference to any particular programming languages, and that a variety of programming languages could be used to implement the present invention. The firmware and/or software codes may be stored in a memory, or embodied in any other processor readable medium, and executed by a processor or processors. The memory may be implemented within the processor or external to the !0 processor.

A processor may be a microprocessor, but in the alternative, the processor may be any suitable processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, for example, a combination of a digital signal processor (DSP) and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP 25 core, or any other such configuration. The processors may function in conjunction with servers and network connections as known in the art.

The steps of a method, process, or algorithm described in connection with the present disclosure may be embodied directly in hardware, in a software module executed by one or more processors, or in a combination of the two. The various steps or acts in a method or process may be performed in the 30 order shown, or may be performed in another order. Additionally, one or more process or method steps may be omitted or one or more process or method steps may be added to the methods and processes. An additional step, block, or action may be added in the beginning, end, or intervening existing elements of the methods and processes.

JAWs ref: 308853AU

BRIEF DESCRIPTION OF DRAWINGS

2019100317 26 Mar 2019

Further aspects of the present disclosure will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which:

FIG. 1-1

FIG. 1-2

FIG. 2

FIG. 3

FIG. 4 is a side view of an exemplary articulated pick and carry crane according to one aspect of the present disclosure;

is an overhead view of the exemplary articulated pick and carry crane;

is a schematic diagram of an exemplary steering control system for use in an articulated pick and carry crane according to one aspect of the present disclosure;

is a schematic diagram of subcomponents of the exemplary steering control system, and is a flow diagram of an exemplary method of controlling an articulated pick and carry crane.

DETAILED DESCRIPTION

FIG. 1-1 and FIG. 1-2 illustrate an articulated pick and carry crane (generally indicated by arrow 100) in accordance with the present invention.

The crane 100 includes a front chassis portion 102 and a rear chassis portion 104. The chassis portions

102 and 104 are connected by pivot couplings 106a and 106b which form an articulation point 5. Two hydraulic actuators (for example hydraulic steering cylinder 108) on either side of the articulation point

110 are controlled to extend and retract, thus pivoting the portions 102 and 104 relative to each other in order to steer the crane 1 as will be discussed in further detail below.

The front chassis portion 102 includes a base pivot mount 112, to which a telescoping boom 114 is coupled. The boom 114 is also coupled to a luffing actuator 116, which may be controlled to adjust the angle of the boom 114. A hoist system including a winch 118 controls the lowering and lifting of a load attachment point 120 (which typically includes a hook - not illustrated).

The front chassis portion 102 further includes an operator cab 12 in which the operator is seated and controls operation of on-road and crane functions.

JAWs ref: 308853AU

2019100317 26 Mar 2019

FIG. 1-2 illustrates articulation ranges (for example, -42°, -21°; -20°, -11°; -10°, 10°; 11°, 20°; and 21°,

42°) of the crane 100, with de-rating of the crane's load moment capacity increasing as the articulation increases. Similar de-rating applies to conditions such as: extension of the boom, and raising the boom.

FIG. 2 illustrates a steering control system (generally indicated by arrow 200) for use in the articulated 5 pick and carry crane 100 illustrated in FIG. 1-1 and FIG 1-2.

The steering control system includes an operator input device 202. By way of example, the operator input device 202 may include a steering wheel connected to a steering unit, wherein rotation of the steering wheel causes the steering unit to output a signal to main steering valve 204. It is envisaged that the steering unit may be purely hydraulic or electrohydraulic, to provide operator response based on 0 changes in the hydraulic flow within the steering system - as described further below. However, in another exemplary embodiment, the operator input device 202 may include an electronic steering unit configured to output an electronic signal to the main steering valve 204. The main steering valve 204 is configured to control hydraulic flow to the first hydraulic cylinder 108a and the second hydraulic cylinder 108b respectively, to carry out steering of the crane.

In the exemplary embodiment illustrated, a first controllable hydraulic valve 206a is provided between the main steering valve 204 and the first hydraulic cylinder 108a, and a second controllable hydraulic valve 206b is provided between the main steering valve 204 and the second hydraulic cylinder 108b.

A load management device 208 is provided to control the first controllable hydraulic valve 206a and the second controllable hydraulic valve 206b. Closure of the valves 206a and 206b reduces the flow of oil to !0 the first hydraulic cylinder 108a and the second hydraulic cylinder 108b, respectively. A reduction in the oil flow produces operator feedback in the form of heavier steering feel in the operator input device 202, and reduces the steering speed. It should be appreciated that for an electronic steering unit, in exemplary embodiments torque feedback may be provided based on sensed characteristics of the hydraulic flow, or mechanical movement of elements of the steering system.

In use, the load management device 208 determines a current load moment of the crane 100 using various parameters of the crane 100. For example, in the exemplary embodiment illustrated, at least one of hydraulic cylinder 108a and/or 108b includes a magnetostrictive linear position sensor configured to communicate the current extension of the cylinder 108, and thereby angle of articulation, to the load management device 208. However, it should be appreciated that other steering angle sensors may be utilised. Further parameters may be provided to the load management device 208 by way of sensors 210, examples of which are discussed further below.

Referring to FIG. 3, the load management device 208 has a processor 302, memory 304, and other

JAWs ref: 308853AU

2019100317 26 Mar 2019 components typically present in such computing devices. In the exemplary embodiment illustrated the memory 304 stores information accessible by processor 302, the information including instructions 306 that may be executed by the processor 302 and data 308 that may be retrieved, manipulated or stored by the processor 302. The memory 304 may be of any suitable means known in the art, capable of 5 storing information in a manner accessible by the processor 302, including a computer-readable medium, or other medium that stores data that may be read with the aid of an electronic device. The processor 302 may be any suitable device known to a person skilled in the art. Although the processor 302 and memory 304 are illustrated as being within a single unit, it should be appreciated that this is not intended to be limiting, and that the functionality of each as herein described may be performed by 0 multiple processors and memories, that may or may not be remote from each other.

The instructions 306 may include any set of instructions suitable for execution by the processor 302. For example, the instructions 306 may be stored as computer code on the computer-readable medium. The instructions may be stored in any suitable computer language or format. Data 308 may be retrieved, stored or modified by processor 302 in accordance with the instructions 306. The data 308 5 may also be formatted in any suitable computer readable format. Again, while the data is illustrated as being contained at a single location, it should be appreciated that this is not intended to be limiting the data may be stored in multiple memories or locations. The data 308 may also include a record 310 of control routines for operation of the load management device 208 - more particularly for controlling the first controllable hydraulic valve 206a and the second controllable hydraulic valve 206b.

!0 The sensors 210 communicating parameters of the crane for use by the load management device 208 in determining the current load moment (or current de-rating of the crane) may include, for example: load sensors 210a (for example, determining the mass of the load carried by the boom), boom sensors 210b (for example, determining extension of the boom, and luffing angle of the boom), steering sensors 210c (for example, determining a current angle of articulation), tilt sensors 210d (for example, determining 25 an angle of the chassis relative to level about one or more axes), and speed sensors 210e.

FIG. 4 illustrates a method 400 of controlling the articulated pick and carry crane. In an exemplary embodiment, in step 402 the load management device 208 determines whether the crane is currently operating in accordance with a crane mode (in contrast with a travel mode in which the crane is configured to travel at higher speeds). If not, the method is discontinued. If operating in a crane mode, 30 the load management device 208 determines whether the crane is currently travelling at a speed above a predetermined threshold (for example 15 kph) in step 404. If the current speed exceeds the predetermined threshold, the method is discontinued. If the current speed is below the predetermined threshold, the load management device proceeds to step 406.

JAWs ref: 308853AU

2019100317 26 Mar 2019

For completeness, it should be appreciated that step 402 and/or step 404 may be performed later in the method - for example after step 412 (described below).

In step 406, the load management device 208 receives current crane parameters from the sensors 210.

In step 408, the load management device 208 determines a current load moment using the received crane parameters, and known crane parameters of a particular crane design - as known in the art.

In step 410, the load management device 208 compares the load moment with warning conditions - i.e. against a risk of a load capacity of the crane 100 being exceeded. In an exemplary embodiment, the warning condition may be reaching a rated limit for the crane 100 - although it should be appreciated that the warning condition may be, for example, within a predetermined factor of the rated limited.

If the warning condition is met, in step 412 the load management device 208 controls the first controllable hydraulic valve 206a and/or the second controllable hydraulic valve 206b to restrict steering in a direction that would increase the load moment. This restriction may remain in place - i.e. stay active - until the load moment is reduced below the warning condition in step 414. Simultaneously, normal flow availability is maintained in the opposite direction to assist with return to a safer condition.

The entire disclosures of all applications, patents and publications cited above and below, if any, are herein incorporated by reference.

Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field !0 of endeavour in any country in the world.

Where in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth.

It should be noted that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be 25 made without departing from the spirit and scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the present invention.

The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

JAWs ref: 308853AU

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof.

2019100317 26 Mar 2019

Claims (5)

1. An articulated pick and carry crane, including:

a chassis including a front chassis portion and a rear chassis portion;

a pivotal connection between the front chassis portion and rear chassis portion;

a steering system configured to rotate the front chassis portion relative to the rear chassis portion about the pivotal connection;

a steering control device, configured to control at least one operating characteristic of the steering system;

a load management device, configured to:

determine a current load moment of the crane;

determine whether the current load moment meets a warning condition;

control the steering control device to restrict rotation about the pivotal connection in a direction that would increase the load moment when the current load moment meets the warning condition.

2. The articulated pick and carry crane of claim 1, wherein the load management device is configured to selectively operate in one of a crane mode, and a travel mode, and wherein the load management device is further configured to only control the steering control device to restrict rotation about the pivotal connection while in the crane mode.

3. The articulated pick and carry crane of claim 1 or claim 2, wherein the load management device is configured to only control the steering control device to restrict rotation about the pivotal connection while the ground speed of the crane is below a predetermined speed.

4. The articulated pick and carry crane of any one of claims 1 to 3, wherein the steering system includes at least one hydraulic steering actuator and the steering control device includes at least one controllable valve, wherein the load management device is configured to control the controllable valve to restrict a flow of hydraulic fluid to the hydraulic steering actuator to restrict rotation about the pivotal connection in the direction that would increase the load moment when the current load moment meets the warning condition.

JAWs ref: 308853AU

2019100317 26 Mar 2019

5. A method of controlling an articulated pick and carry crane having a pivotal connection between a front chassis portion and a rear chassis portion, the method including:

determining a current load moment of the crane;

determining whether the current load moment meets a warning condition;

controlling steering of the crane to restrict rotation about the pivotal connection in a direction that would increase the load moment when the current load moment meets the warning condition.