GB2527598A

GB2527598A - A material handling machine

Info

Publication number: GB2527598A
Application number: GB1411494.6A
Authority: GB
Inventors: Mike Mckee; Brice Bozier; Gary Powell
Original assignee: JC Bamford Excavators Ltd
Current assignee: JC Bamford Excavators Ltd
Priority date: 2014-06-27
Filing date: 2014-06-27
Publication date: 2015-12-30
Anticipated expiration: 2034-06-27
Also published as: GB201411494D0; GB2527598B

Abstract

A material handling machine 10 including a chassis 12 , an implement support system 18 moveably mounted relative to the chassis, an implement 24 moveably mounted relative to the implement support system, an implement actuator system 36 for moving the implement relative to the implement support system 18, a sensing means for providing a signal representative of an inclination of the implement (64 fig 2) and an input means (66 fig 2) for inputting a desired inclination (67 fig 2) of the implement to a control system (52 fig 2). The system being arranged such that during movement of the implement support system 18 relative to the chassis, the control system 52 receives a signal (65 fig 2) representative of the inclination of the implement and provides a signal to the implement actuator system 36 to maintain the implement in the desired inclination by moving the implement relative to the implement support system.

Description

A Material Handling Machine The present invention relates to a material handling machine.

Known material handling machines such as excavators have a material handling arm assembly. The arm assembly may have an arm, known as a boom, pivotally mounted about a generally horizontal axis relative to a chassis of the machine. A further arm, known as a dipper, may be attached to an end of the boom remote from the chassis and may be pivotable about a generally horizontal axis. A material handling implement such as a bucket may be pivotably mountcd on an end of thc dippcr. Thc boom may be raised and lowered by operation of a first hydraulic ram. The dipper may be moveable relative to the boom by operation of a second hydraulic ram, the bucket may he moveable relative to the dipper by operation of a third hydraulic ram.

In order to handle material, for example dig a trench, a machine operator must simultaneously operate all three hydraulic actuators aM this is a skilful process. A skilful operator, when digging a trench, will quickly he able to fill the bucket with material, lift bucket out of the trench and empty the bucket to one or other side of the vehicle. This excavation cycle time or loading cycle time is markedly affected by the initial penetration of the bucket into the ground. If the bucket penetrates too far into the ground then the bucket cannot he drawn through the ground to he filled.

Converscly if thc bucket does not penetrate far cnough into the ground. thcn the bucket only half fills. Less well trained operators tend to operate at lower excavation! loading cycle times. In particular, less well trained operators find ii. difficult to dig trenches with hat bottoms.

Accordingly. there is a need for an improved material handling machine.

Thus, according to the present invention there is provided a material handling machine including: a chassis, an implement support system moveably mounted relative to the chassis.

an implement moveably mounted relative to the implement support system, an actuator system for moving the implement relative to the implement support system.

means for providing a signal representative of an inclination of the implement S relative to a coordinate system.

an input means for inputting a desired inclination of the implement.

a control system being arranged such that during movement of the implement support system relative to the chassis the control system receives a signal representative of the inclination of the implement relative to the coordinate system from the means, and the actuator system receives a signal from the contro' system to maintain the implement in the desired inclination by moving the implement relative to the implement support. system.

Advantageously, since the processor maintains the imp'ement in a desired inclination.

the operator need not control the inclination of the implement and can therefore concentrate on controlling movement of the implement system.

The invention will now he described, by way of example only, with reference to the accompanying drawings in which:-Figure 1 is a schematic side view of a material handling machine according to the present invention, and Figure 2 is a schematic view of part of the material handling machine of figure 1.

With reference to figures 1 and 2 there is shown a material handling machine 10 including a chassis 12 and an operator cab 14. The operator cab is niounted on the chassis 12. Ground engaging transport means in the form of a pair of tracks 16 are provided to move the machine over the ground.

Attached to the chassis is an arm assembly 18 (also known as an implement support system), the arm assembly includes a first anTi in the foim of a boom 20, a second arm in the form of a dipper 22 and a ground engaging implement in the form of a bucket 24. The boom 20 is pivotally mounted by pivot 26 to link 12A at a first end 20A of the boom. Link 12A is pivotally mounted at a generally vertical axis relative to the chassis 12. Pivot 26 is orientated horiiontafly. The dipper is pivotally mounted via pivot 28 to a second end 20B of the boom 20. Pivot 28 is orientated horizontally. The S bucket is pivotally mounted via pivot 30 to an end 22B of dipper 22 remote from end 22A of dipper 22. Pivot 30 is orientated horizontally.

A first hydraulic actuator in the form of a first hydraulic ram 32 has a first end 32A pivotally attached to the link 12A and a second end 32B pivotally attached to the boom part way between the first and second ends of the boom. A second hydraulic actuator in the form of a second hydraulic ram 34 has a first end 34A pivotally attached to the boom part way between the first and second ends of the boom and a second end 34B pivotally attached to the dipper proximate the first end 22A of the dipper. A third hydraulic actuator in the form of a third hydraulic ram 36 has a first end 36A pivotally attached to the dipper proximate the first end 22A of the dipper and a second end 36B pivotally attached to a linkage mechanism 38 proximate the second end 22B of the dipper. The linkage mechanism 38 per se is known and simply converts extension and retraction movement of the third hydraulic ram 36 into rotary movement of the bucket 24 about pivot 30.

Extension of the first hydraulic ram causes the boom to raise, and contraction of the first hydraulic ram causes lowering of the boom. Extension of the second ram causes the dipper to pivot in a clockwise direction (when viewing figure 1) about pivot 28.

i.e. causes the dipper to move in a "dipper in" direction, and retraction of the second hydraulic ram 34 causes the dipper to move in an anticlockwise direction when viewing figure 1 about pivot 28, i.e. in a "dipper out" direction. Extension of the third hydraulic ram 36 causes the bucket 24 to move in a clockwise direction about pivot 30. i.e. in a "crowd" direction, and retraction of the third hydraulic ram 36 causes the bucket to move in an anticlockwise direction about pivot 30. i.e. in a "dump' direction.

The first, second and third hydraulic rams are all double acting hydraulic rams.

Double acting hydraulic rams are known per se. They include a piston within a cylinder. The piston is attached to a rod which extends beyond the end of the cylinder. The end of the rod remote from the piston defines one end of the hydraulic ram. The end of the cylinder remote from the rod defines an opposite end of hydraulic ram. A "head side chamber" is defined between the piston and the end of the cylinder remote from the rod. A "rod side chamber" is defined between the piston and the end of the cylinder proximate the end of the rod. Pressurisation of the head side pressure chamber extends the ram and pressurisation of the rod side chamber causes the ram to retract.

The machine includes a system for operating the first, second and third hydraulic rams, as described below.

A hydraulic pump 40 (see figure 2) driven by a prime mover 41. Prime mover 41 may be an internal combustion engine, though other prime movers are suitable. A boom spool valve 44 can he operated by an operator manipulating boom control 46. In this case boom control 46 is a joystick. A dipper spool valve 48 can be controlled via a dipper control 50. In this case dipper control 50 is a joystick. An implement spool valve 54 can be operated by an operator manipulating implement control 56. In this case implement control 56 is a joystick. Joysticks 50, 46 and 54 may be separate joysticks (as shown in Fig. 2). Alternatively two of the dipper control, implement control and boom control may be combined in a single joystick. Alternatively all three of the dipper control, boom control and implement control may be combined in a single joystick. Controls other than joysticks may he used to control one or more of the dipper spool. the boom spool or the implement spool.

The material handling machine also includes a control system 52. The control system 52 includes a sensor in the form of an inclinometer 64, a processor 60 including a memory 62 (such as data storage) an input means 66 and an enabling/disabling means 68. The control system sdectively controls the implement spool valve 54 as wifl he further described below.

Operation of a material handling machine is as follows:-The control system 52 can be selectively enabled or disabled at the option of the operator. ffi order to enable the control system 52 the operator actuates enahlingldisahling means 68 which is in a form of a switch, button or other operator input device. In order to disable the control system 52 the operator actuates the enabling/disabling means 68.

Operation of machine with the control system 52 disabled, is as follows:-The prime mover 41 drives the hydraulic pump 40 which takes hydraulic fluid from tank T and pressurises hydraulic line Li. As shown in figure 2 the dipper spool valve is closed the implement spool valve 54 is closed and the boom spool valve is dosed and hence pressurised fluid in line Li will pass through the relief valve 51 back to tank T. 11 it is desired to raise the boom the boom control 46 is operated such that the boom spool 44A of the boom spool valve 44 is moved so as to connect hydraulic line Li and L2. This causes hydraulic fluid to pass into the head side pressure chamber of the first hydraulic ram thereby extending the hydraulic ram and raising the boom. Hydraulic fluid from the rod side chamber passes into hydraulic line L3 and back to tank T via the boom spool valve 44. hi order to lower the boom the boom control 46 is operated to move the boom spool 44A in the opposite direction thereby connecting hydraulic line Li with L3 and hydraulic line L2 with tank T. In order to move the dipper in a dipper in' direction the dipper control 50 is operated such that the dipper spool 48A of the dipper spool valve 48 connects line Li with hydraulic line L4. Hydraulic line L4 is connected to the head side of the hydraulic ram 34 which causes the ram to extend thereby pivoting the dipper ann in a clockwise direction about pivot 28. Hydraulic fluid in the rod side of hydraulic ram 34 passes into line L5 and then on through the dipper spool va've 48 to tank T. In order to move the dipper in a dipper out' direction the dipper control 50 is operated such that the dipper spool connects line LI with L5 and connects line L4 to tank. This results in retraction of the hydraulic ram 34 thereby causing the dipper to move in an anticlockwise direction about pivot 28.

In order to move the bucket in a "crowd" direction the implement control 56 is operated such that the implement spooi 54A of the implement spool valve 54 connects line Li with hydraulic line L6. Hydrauiic line L6 is connected to the head side of the hydraulic ram 36 which causes the ram to extend thereby pivoting the implement in a clockwise direction about pivot 30. Hydraulic fluid in the rod side of hydraulic ram 36 passes into line L7 and then on through the implement spool valve 54 to tank T. In order to move the bucket in a "dump" direction the implement control 56 is operated such that the implement spooi 54A connects line Li with L7 and connects line L6 to tank. This results in retraction of the hydraulic ram 36 thereby causing the bucket to move in an anticlockwisc direction about pivot 30.

When digging a trench or the like a typical sequence of movements of the arm assembly is as follows:-Firstly. the boom is lowered and the dipper is moved in a "dipper out" dircction thereby moving the bucket teeth 25 of the bucket 24 away from the chassis 12. The boom is then further lowered such that the bucket teeth 25 engage the ground. The bucket is then crowded slightly so as to start to move the bucket teeth through the ground. The dipper control 50, boom control 46 arid bucket control are then simultaneously operated to progressively move the dipper in a "dipper in' direction and to move the boom in a "boom raised" direction and to move the bucket in a "crowd" direction such that the bucket teeth move generally towards the chassis. As will be appreciated, skill is involved in simultaneously manipulating the dippcr control 50 and the boom control 46 and the bucket control 56 to efficiently fill the bucket with ground material. Once the bucket is full, the boom is raised, the arm assembly is swung laterally rclativc to thc machine and thc ground material is thcn dumped by moving the bucket to a dumped position. The sequence is then repeated.

In particular, when digging a trench it is often desirable for the base of the trench to he flat. This is particularly the case when a pipe or cable is to he laid in the trench.

Providing a trench with a flat base means that a minimum amount of material has to be removed from the trench in order to lay the pipe or cable at the required depth below nominal ground level. In particular, known systems with booms and dippers and buckets, make digging of a trench with a flat base difficult because as the boom is raised and the dipper is moved in a dipper in direction the bucket tends to naturally crowd and therefore the operator has to partially dump the bucket in order to dig a flat S bottomed trench. Simultaneously operating a boom control, a dipper control and a bucket control is difficult to achieve.

The control system of the present invention enables a trench with a flat base to be more easily dug.

When enabled the control system 52 operates to ensure the bucket is automatically crowded or dumped so as to maintain a correct orientation of the bucket relative to the ground. The control system 52 includes a processor 60. in one embodiment a microprocessor. The control system is also includes a memory 62 such as data storage, such as hash memory. A sensor 64 is capable ol providing a signal representative of the inclination of the bucket 24. In one embodiment the sensor 64 is an inclinometer. In this example the inclinometer is directly attached to the bucket so as to move with the bucket. The processor 60 can receive signals via line 65 from the inclinometer 64. An input means 66 is capable of inputting a desired inclination of the bucket 24. The processor 60 can receive a signal, via line 67. from the input means 66. the signal being indicative of the desired inclination of the bucket 24.

Operation of a material handhng machine with a control system 52 enabled is as follows:-The operator operates the input means 66 to provide a desired inclination of the bucket 24. In one embodiment the input means may be a dial or other device for inputting any desired inclination.

In an altemative embodiment the operator may set the bucket to the desired inclination by operating the implement control 56. Once the bucket is in the desired orientation then the operator may operate the input mems 66 indicating that the desired inclination of the implement is the current inclination of the implement.

If it is desired to dig a trench with a horizontal flat base, then the desired inclination of the bucket is such that the bucket sole plate 24A (i.e. that part of the bucket immediately adjacent to the bucket teeth) is horizontal. Keeping the bucket sole plate S horizontal also reduces the energy required to cut through the ground. thereby improving the cycle time and energy efficiency. The desired inclination of the implement may he stored in memory 62 associated with the processor.

Once the desired inclination of the implement has been set the control system 52 is enabled by the operator actuating the enabling/disabling means 68. When the boom and/or dipper are then moved the inclination of the bucket will change. This change in inclination will be registered by the inclinometer 64 and a signal indicative of the inclination of the bucket will be sent by the inclinometer to the processor. The processor then compares the single representative of the inclination of the implement with die desired inclination of the implement and when the desired inclination differs from the current inclination the processor generates a signal to either crowd or dump the bucket such that the inclination of the bucket moves towards the desired inclination.

The control system 52 may include a proportional and integral PI) type controller.

The output from the inclinometer may be filtered, for example by using a butterworth or similar filter. A mode switch (not shown) allows selection of the type of operation being formed, for example grading, excavating or pallet fork operation. The mode switch allows the gain and integrating parameters for a PT controller to be automatically set for a particular activity. The PT controller may utilise a bipolar pulse width modulated (PWM) output to control the bucket crowd and dump pilot line solenoids 54b, 54c. As the bucket moves away from the desired inclination, the controller outputs a PWM signal to compensate.

When the current (or instantaneous) inclination of the implement differs from the desired inclination the control system may output an error warning. The error warning may be in the fomi of a flashing visible warning light. The warning light may be mounted in the operator cab or may be mounted on the arm assembly 18 or may be mounted on the bucket 24. When the indicator light is off the system is deactivated.

When the indicator light is on the system is active and the instantaneous inclination of the implement is the same as the desired inclination. When the indicator light flashes the instantaneous inclination of the implement may differ from the desired inclination S of the implement. The frequency of the flashing light may indicate the amount of difference between the instantaneous inclination of the implement and the desired inclination of the implement.

The desired inclination of the implement may be a limited range of inclinations, for example 0° ± 5°. In this manner the instantaneous inclination of the implement may he kept within the desired range of inclinations.

The invention as described above has been described with respect to digging trenches with horizontal flat bases. However, the invention is equally applicable to digging trenches with flat bases where the base is not horizontal.

The invention has been described above with respect to the digging trenches with flat bases. However the invention is equally applicable to performing other operations, for example "grading out". During a "grading out" process the sole plate of the bucket is orientated horizontally and the bucket is moved away from the machine chassis smoothing down a ground surface. As the bucket is moved away from the chassis, the bucket tends to dump relative to the ground surface and this dumping tendency is automatically corrected by the control system of the present invention if enabled.

The invention can also be used in conjunction with other implements which require colTect alignment, such as grabs, augers and hammers. For example. the invention can maintain a hammer or an auger in a vertical orientation at all times hence reducing the need for the operator to check the alignment.

Advantageously, the invention can he used where the operator does not have line of sight of the implement. for example during dredging or when the implement is being pulled through a deep pile of material. The invention reduces operator fatigue since the attachment is automatically kept at the desired inclination. Because the implement is maintained at a correct inclination the operator is free to concentrate on adjusting of the other controls.

As described above the material handling machine 10 includes an enabling/disabling S means 68. This is shown as a separate device in figure 2 but could be incorporated into other devices, for example could be incorporated into implement control 56. In further embodiments enabling of the control system could he carried out separately from the disabling of the control system. For example a switch, button or other operator input, device could enable the system and a different switch, button or other operator input device could disable the system. In particular a particular sequence of operator input could enable and disable the system. For example to enable the system a switch, button or the like could be operated once and to disable the system the switch, button or the like could be operated twice in quick succession. Other operator inputs could be used to deactivate the system, for example a switch, button or the like could he depressed and held for a pre-determined amount of time!èr examp'e 3 seconds to disable the system. Alternatively operation of the implement control 56 could disable the system. In one embodiment only operation of the implement control 56 beyond a pre-determined amount may disable the system. Thus a large input to the implement control 56 may disable the system. whereas a relatively small input to implement control 56 may allow a "feathering" amount of manual input to the inclination of the implement.

As described above, the sensor 64 is mounted on the bucket. However, the sensor need not be mounted directly on the implement. rather the sensor may be mounted on a part of the linkage mechanism 38, the inclination of which has a known relationship to the inclination of the bucket.

"Quick hitch" devices are known where by when part of the quick hitch is mounted on an end of the dipper and another part of the quick hitch is mounted upon a bucket.

The quick hitch allows quick attachment of the bucket to the machine via the quick hitch device An inclinometer, or other means for providing a signal representative of an inclination of the implement may be mounted on part of the quick hitch device, in particular may be mounted on that part of the quick hitch which is mounted on the dipper, or that part of the quick hitch which is mounted on the implement.

As described above and as shown in the drawings, the materials handling machine 10 S is an excavator. However, the present invention is applicable to other types of material handling machines. for example a backhoe loader. As described above, the excavator 10 has a pair of tracks. The invention is equally applicable to material handling machines having other types of ground engaging transport means, for

example wheels.

As described above the implement support system is moved hydrauficafly, though in further embodiments this need not be the ease. As described above the implement is moveably mounted relative to the implement support system via hydraulic system, though in further embodiments this need not be the ease.

Claims

Claims I. A material handling machine including a chassis, an implement support system moveably mounted relative to the chassis.an implement moveably mounted relative to the implement support system.an actuator systcm for moving thc implcmcnt rclativc to thc implement support system.means for providing a signal representative of an inclination of the implement relative to a coordinate system.an input means for inputting adcsired inclination of the implement, a control system being alTanged such that during movement of the implement support system relative to the chassis the control system receives a signal representative of the inclination of the implement relative to the coordinate system from the means, and the actuator system receives a signal from the control system to maintain the implement in the desired inclination by moving the implement relative to the implement support system.
2. A material handling machine as defined in claim 1 wherein the coordinate system is a &ohal coordinate system.
3. A material handling machine as defined in claim 1 or 2 wherein the means for providing a signal representative of an inclination of the implement is an inclinometer.
4. A material handling machine as defined in claim 3 wherein the inclinometer is mounted so as to directly indicate the inclination of the implement.
5. A material handling machine as defined in claim 4 wherein the inclinometer is mounted directly on thc implcmcnt so as to move with the implement.
6. A material handling machine as defined in any preceding claim wherein the implement support system includes an implement support system attachment arrangement and the implement indudes an implement attachment arrangement and the means for providing a signal representative of an inclination of the implement is S attached to the implement support system attachment arrangement or the implement attachment arrangement.
7. A material handling machine as defined in any preceding claim wherein the input means is capable of inputting a desired inclination of the implement different to a current inclination of the implement.
8. A material handling machine as defined in any preceding claim wherein the input means is capable of inputting a current inclination of the implement as the desired inclination of the implement.
9. A material handling machine as defined in any preceding claim wherein the control system can he selectively enabled and/or sdectively disabled.
10. A material handling machine as defined in claim 9 wherein the control system is selectively enabled and/or selectively disabled by operation of an implement control.
11. A material handling machine as defined in any preceding claim wherein the control system indudes a processor.
12. A material handling machine as defined in claim 11 wherein the desired inclination of the implement is stored in memory.
13. A material handling machine as defined in claim 11 or 12 wherein the processor is configured to receive the signal representative of an inclination of the implement and is conligured to compare said signal with the desired inclination of the implement and when a current inclination of the implement differs from the desired inclination the control system outputs an error warning.
14. A material handling machine as defined in any preceding claim in which the implement is a ground engaging implement.
15. A material handling machine as dcflned in any preceding claim whcrein the control system may be enabled and may be disabled.
16. A material handling machine as defined in claim 15 whemin the control system is disabled when an error between a current implement inclination and a desired implement inclination exceeds a predetermined value.
17. A material handling machine as defined in claim 16 whemin the control system is disabled by inputting a desired inclination of the implement which differs by more than the predetermined value from the current inclination of the implement.