BACKGROUND OF THE INVENTION:

1 . Field of the Invention:

[0001 ] This invention relates to a mass flow device for mobile wood chipping harvesting machines

[0002] The invention particularly relates, but is not limited to, a mass flow device for mobile wood chipping machines, such as tree harvesters suitable for harvesting shrubs, coppice, or tall single stem trees, where such trees are planted at preferably regular spacing in rows.

2. Dictionary

[0003] The term "trees" shall be used throughout the specification to describe shrubs and trees which have either a single-stemmed form; or a plurality of coppice stems extending generally upwards from a tree stump or lignotuber; and by example, includes trees of the Eucalyptus and Acacia genera indigenous to Australia; and of the Salix and Populus genera indigenous to Europe and North America.

[0004] The term "in a substantially vertical position" will be used throughout the specification to indicate that a stem of a tree is inclined at an angle (preferably) no more than 30° to the vertical Z axis

[0005] The term "harvester" will be used throughout the specification to define a chipper device, mounted to a mobile vehicle that moves along row of trees, continuously chipping each stem into a desired particle size.

[0006] The term "pour rate" will be used throughout the specification to define the speed that chipped material flows through the harvester and is measured in green metric tons per hour. This is an important measurement of performance of the tree harvesters.

3. Prior Art

[0007] NB: The following discussion is by way of background information only, and is not to be considered a statement of the common general knowledge (CGK) in the area of technology, anywhere in the world. {0008] It has been proposed, internationally, to grow trees (as hereinbefore defined) of the Eucalyptus, Populus and Salix genera as an ecologically- based energy and fiber feedstock.

[0009] As the Eucalyptus, Populus and Salix genera are fast-growing, their biomass can be used as a "renewable" source of energy, fibreboard or paper pulp, as the trees can be harvested every 2-6 years.

[0010] The key challenge has been the ability to economically chip the trees and transport the chipped biomass from the tree growing areas to industry processors e.g., fiberboard and paper manufacturers, electricity generators, heat users and biofuel convertors.

[001 1 ] Efforts to solve this challenge have initiated research to develop efficient continuous tree chipper harvesters in Australia to improve pour rate productivity measured in terms of weight or volume per hour, thereby reducing the cost of chipping trees.

[0012] Example of two such "PRIOR ART" prototype continuous tree chipper harvesters will now be described.

[0013] International Patent application PCT/AUOO/00171 (= International Publication WO 00/52998) (Oil Mallee Company of Australia Pty Ltd) discloses a tree harvester ("the Giles harvester") mounted on a tractor, where transport means, in the form of vertically-spaced endless chain conveyors, engage the substantially vertical tree stems just before the trees are cut adjacent the bases of the stems by a rotary saw. The transport means convey the tree stems, in a substantially vertical position, towards a chipper drum rotating about a substantially horizontal axis. Counter-rotating feed rollers, and an adjustable anvil, mounted adjacent to the chipper drum, direct the stems of the trees into the chipper drum at an angle between 90° and 30° from the vertical, with the stems being guided and supported by a pair of adjustable plates while being chipped. By adjusting the location of the plates and the anvil relative to the (conventional) chipper drum, a wide range of trees can be harvested.

[0014] International Patent Application PCT/AU2010/000403 (= International Publication WO 2010/129986) (Future Farm Industries CRC Limited) discloses a tree harvester ("the Sulman harvester") which has advantages over the Giles harvester, in that the tree stems are fed substantially vertically to a chipper drum, rotating about an axis inclined at a small angle to the horizontal axis, and parallel with the direction of travel of the tree harvester. At least one pair of opposed nip rollers feed the tree stems downwardly, and rearwardly, to the chipper drum, so that the tree stems are progressively chipped as they are fed into, and along, the full length of the chipper drum. Unlike the Giles harvester, no energy and time is wasted in tipping the tree stems from the original orientation in which they are feed to the chipper drum, and the wear on the knives of the chipper drum is more evenly spread along the length of the chipper knives, extending the periods between re- sharpening. In addition, the parallel orientation of the chipper drum enables the simultaneous chipping of two or more stems in single file. This results in greater operational and energy efficiency, leading to a higher pour rate for the Sulman harvester than is possible by the Giles harvester.

[0015] While the Sulman harvester enables improved productivity, and thereby lower operating costs, than existing tree harvesters, there is no effective measurement of the specific yields of the trees on a specific site, or in a portion of a very large site.

[0016] In addition, there is no effective measurement of the tree harvester's specific energy performance, being the calculation of measured fuel consumed per time (KJ/sec) divided by the measured mass of wood chipped per time (Kg/sec), i.e. KJ/Kg. Thereby, the mass flow is an important measurement to give the operator a real-time understanding of the sharpness of the cutting edges, i.e. higher specific energy indicates edge wear, allowing the operator to sharpen the blades as required to lower energy costs and increase overall chip quality.

OBJECTS OF THE INVENTION:

[0017] It is an object of the present invention to provide a mass flow device for mobile chipping machines which overcomes, or at least ameliorates, at least one of the problems with existing tree harvesters and other mobile chipping machines.

[0018] Other preferred objects of the present invention will become apparent from the following description.

SUMMARY OF THE INVENTION:

[0019] In one aspect, the present invention resides in a mass flow device for a mobile wood chipping harvesting machine including:

an outlet passage operably connected to a chipping device and arranged to allow chips to pass therethrough;

a curved wall portion in, or of the, outlet passage operable to be impacted by the chips passing through the outlet passage; and

sensor means operably connected to the curved wall portion to measure strain and/or other parameters of the curved wall portion as an indication of mass flow rate of the chips through the outlet passage.

[0020] Preferably, the mass flow device is provided upstream of an accelerator operably connected to the outlet passage to promote the flow of chips through the outlet passage.

[0021 ] Preferably, the curved wall portion is a concave portion of an outer wall of the outlet passage.

[0022] Preferably, the accelerator has a housing to one side of, but connected to, the outlet passage;

the accelerator has a shaft rotatably journalled in the housing about an axis of rotation substantially parallel to the flow of the chips past the housing;

a plurality of accelerator blades extend radially from the shaft and travel through the outlet passage as the shaft is rotatably driven;

the outlet passage has a flexible wall portion opposite the accelerator blades and

a control mechanism is operably connected to the flexible wall portion to flex the flexible wall portion towards, or away from, the accelerator blades to adjust the gap there-between, and thereby adjust the rate of flow of the chips through the outlet passage.

[0023] Preferably, the control mechanism includes:

a cam roller rotatably journalled externally of the outlet passage, in cam-like engagement with the flexible wall portion; and

ram and lever means operably rotate the cam roller the flex the flexible wall portion.

[0024] Preferably, the ram and lever means is connected to a CPU operably connected to the sensor means.

[0025] In a second aspect, the present invention resides in the accelerator assembly hereinbefore described.

[0026] Other preferred aspects of the present invention will become apparent from the following description. BRIEF DESCRIPTION OF THE DRAWINGS:

[0027] To enable the invention to be fully understood, and to enable the skilled addressee to put the invention into practice, a number of preferred embodiments will now be described, with reference to the accompanying illustrations, in which:

FIG. 1 is a schematic, part-sectional, isometric view of a portion of a tree harvester provided with a mass flow device in accordance with a first embodiment of the present invention;

FIG. 2 is a rear isometric view of the mass flow device on a larger scale;

FIG. 3 is a schematic sectional side view corresponding to FIG. 1 ;

FIG. 4 is a schematic circuit diagram of the mass flow device;

FIG. 5 is a schematic control circuit measuring engine performance against the pour rate of the chips, measured by the mass flow device, to initiate the sharpening system for the knives of chipping drum.;

FIG. 6 is a rear isometric view of a modified accelerator suitable for use with the mass flow device; FIG. 7 is a schematic, part-sectional, side view of a portion of the tree harvester provided with the mass flow device and incorporating the modified accelerator of FIG. 6; and

FIGS. 8 and 9 are part-sectional side views, from the opposite side, illustrating the operation of the modified accelerator.

[0028] NB: Any annotations on the drawings are by way of illustration only, and are not limiting to, or form part of, the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:

[0029] Referring to FIGS.1 to 3, the mass flow device 10 of a first embodiment of the present invention is provided adjacent a chipping drum CD and associated anvil assembly A of a tree harvester H, generally of the Sulman harvester type, parts of which are omitted for clarity. Trees T are harvested in rows and the upper portions may be defoliated by a flailer (not shown). The trees T are fed substantially vertically through a pair of nip rollers NR to the chipping drum CD. The chips C travel up through an outlet passage 20 to a bin or hopper (not shown), which may be towed by the harvester H or hauled alongside the harvester H. A mass flow sensor 40 monitors the pour rate of the chips C from the chipping drum CD and passing through the outlet passage 20.

[0030] As better illustrated in FIG. 2, the outlet passage 20 is of substantially rectangular cross-section, and defined by an inner (or front) wall 21 , an outer (or rear) wall 22, and a pair of side walls 23, 24.

[0031 ] The outlet passage 20 is upwardly inclined and has a curved, mass flow measuring section 30, operably connected to an accelerator assembly 60. The accelerator is immediately downstream of the mass flow sensor 40. The outlet passage 20 has an exhaust outlet 25 which delivers the chips C to the bin or hopper.

[0032] The mass flow measuring section 30 has a concave outer wall 31 which is impinged by the chips C passing up the outlet passage 20. The lower portion 32 of the curved outer wall 31 is hingedly connected to the adjacent outer wall 22 via hinges 33. The upper portion 34 of the curved outer wall 31 is engaged by one or more strain sensor(s) 40 mounted on bracket(s) 41 on the outer wall 22 of the outlet passage 20.

[0033] As the mass flow of the chips C travelling up the outlet passage in the direction of arrow A increases, a greater load will be applied to the curved outer wall 31 , as indicated by arrows B, and the curved wall portion 31 will try to pivot outwardly; and this movement, indicated by arrow D, will be measured by the strain sensor(s) 40.

[0034] As illustrated in FIG. 4, the sensors 40 can be connected to a CPU, which can receive other inputs from the harvester H, including fuel consumption of the engine E and ground speed of the harvester H ; and the CPU can calculate the specific yield of chips C and forward this information to a display in the operator's station OS.

[0035] The CPU can be programmed to provide simultaneous or historical outputs, and the latter can be processed to provide the operational history of the harvester H and the chip yields for selected sites to enable suitable comparisons to be determined.

[0036] Referring now to FIG. 5, the CPU can monitor the flow rate of the chips C via the mass flow sensor 40 and the fuel consumption of the engine E. When fuel consumption for the engine E exceeds a first preset limit for the flow rate of the chips C, a warning signal sent be sent to the operator's station OS warning the operator that the chipping drum knives will shortly need sharpening and e.g. can be carried out at the next break in operation e.g. for refueling the harvester H or during the operator's scheduled break. If a second preset limit is reached, the CPU can send a signal to the operator's station OS that the harvester H must be stopped to enable the knives to be sharpened immediately, as the fuel consumption is such that the operation of the harvester H is now, or becoming, uneconomic.

[0037] The skilled addressee will appreciate that the CPU can be "mapped" so that different types of trees being harvested can be allowed for - typically the fuel consumption rate for softwoods will be lower than for harder woods. In addition, the CPU can taken into consideration the ground speed of the harvester H along the rows of trees T and/or other factors which may affect the fuel consumption rate.

[0038] Tests have established that the flexibility to adjust the gap a between the outer wall 22 and the accelerator paddles is critical, according to the mass flow and type of material being chipped. FIGS. 6 to 9 illustrate a method of, and apparatus for, adjusting the gap a by bending the outer wall 22 of the outlet passage 20 inwardly and outwardly by means of an external cam roller.

[0039] The accelerator assembly 60 has a housing 61 offset from, but operably connected to, the outlet passage 20. The accelerator 60 has a shaft

62 rotatably journalled in the housing 61 about an axis of rotation 63 substantially parallel to the flow of chips C through the outlet passage 20.

[0040] Accelerator paddles or blades 64 are provided extending radially from a cylindrical hub 65 mounted on the shaft 62, and the tips of the paddles define a path, of radius r, extending into the outlet passage 20, so that the paddles 64 travel though the outlet passage 20 as the shaft 62 is driven by a motor (not shown).

[0041 ] A portion 66 of the outer wall 22 of the outlet passage 20 , adjacent the path of the paddles 64 of the accelerator 60, is flexible and is anchored at the upper edge 67 but the lower edge 68 is in sliding (sealed) engagement with adjacent upstream portion of the outer wall 22.

[0042] A cam roller 69 has a substantially cylindrical body 70 with hinge spigots 71 at each end of the roller body 70, where the hinge spigots 71 are offset from the central axis 72 of the roller body. The hinge spigots 71 are rotatably journalled in a pair of support brackets 73 on the outer wall 22, so arranged that as the roller body 70 is rotated, the roller body 70 engages the outer face 74 of the flexible wall portion 66 with a cam-like action.

[0043] A control lever 75 is connected to the cam roller 69, and its distal end is connected to the distal end of the piston rod 76 of a control ram 77, the cylinder 78 of which is also mounted on brackets 79 on the outer wall 22..

[0044] As illustrated in FIGS. 8 and 9, rotation of the control lever 75, by the control ram 77, illustrated by arrows F , causes the roller body 70 to move the flexible wall portion 66 inwardly, or outwardly, relative to the accelerator paddles 64, as illustrated by arrows G, to vary the distance a there-between. As the distance a is reduced, the flow rate of the chips C through the gap a is increased. The control ram 78 may be connected to the CPU and operated to vary the gap a to provide optimum operation of the chipping machine.

[0045] The skilled addressee will readily appreciate that the present invention provides real-time plantation wood chip yield down to small resolution. Normally, the trees are cut and moved from their standing position before their stem mass is recorded, therefore only providing average yields, not site specific yields.

[0046] The present invention will enable useful GIS data to be generated, thereby enabling prescriptive responses to site-specific issues, such as nutrition, soil type, moisture content - compared with plant traits, such as genetic selection.

[0047] The skilled addressee will also readily appreciate that the mass flow device, including its sensor, will enable yield mapping of forestry plantations to occur in real-time, plus its fitment will enable the operator to measure mass flow against fuel consumption to reveal real-time specific energy of the chipping process, i.e. KJ/Kg. This is a very important unit to determine when to sharpen the knives or blades. The mass flow sensor enables an automated chipper knife or blade sharpener to be fitted to the harvester to further maximise harvesting efficiency and economic operation of the forests.

[0048] The advantages of the present invention listed above are by way of example only, and the skilled addressee will appreciate the list is not limiting.

[0049] Various changes and modifications may be made to the embodiments described and illustrated without departing from the present invention.

[0050] In this specification, the terms 'comprises', 'comprising', 'includes', 'including', or similar terms are intended to mean a non-exclusive inclusion, such that a method, system or apparatus that comprises a list of elements does not include those elements solely, but may well include other elements not listed.