CA2921720C - A timber-working device and method of determining the number of stems held by the device - Google Patents
A timber-working device and method of determining the number of stems held by the device Download PDFInfo
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- CA2921720C CA2921720C CA2921720A CA2921720A CA2921720C CA 2921720 C CA2921720 C CA 2921720C CA 2921720 A CA2921720 A CA 2921720A CA 2921720 A CA2921720 A CA 2921720A CA 2921720 C CA2921720 C CA 2921720C
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Abstract
A timber-working device and method of operation are provided for distinguishing between circumstances in which two tree stems are processed by the timber-working device, and a number other than two. The method includes holding at least one stem using at least one pair of arms moveably connected to a frame of the timber-working device. A signal is output indicative of a distance between the frame and a frame facing surface of the stem(s) from a sensing device having a sensing path extending between the frame and the stem(s). The signal indicative of the distance between the frame and the frame facing surface of the stem(s) is received, and a determination made whether the number of stems currently held by the pair of arms is two, or a number other than two, based at least in part on the signal.
Description
A TIMBER-WORKING DEVICE AND METHOD OF DETERMINING THE NUMBER
OF STEMS HELD BY THE DEVICE
FIELD OF THE DISCLOSURE
The present invention relates to a timber-working device and method of operation.
BACKGROUND
It is well-known to mount timber-working devices, commonly referred to as forestry or harvester heads, to a carrier vehicle in order to perform a number of operations in connection with timber processing. These operations may include one, or a combination of, grappling and felling a standing tree, and processing one or more resulting stems by delimbing, debarking, and cutting those stems into logs.
The number of stems being concurrently processed heavily influences the manner in which measurements (such as diameter and length measurement) are to be interpreted ¨
for example when calculating the number and length of logs to be cut from a stem, or evaluating productivity such as volume and harvesting intensity (essentially the number of stems per land area unit). For accuracy, the number of stems needs to be known.
One method for accomplishing this would be to have the operator of the head manually input the number of stems being processed. However, it is generally desirable to reduce the burden on operators in order to reduce stress and fatigue, which can in turn lead to poor decision making with regard to control of the head and lost value to the forest owner.
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
No admission is made that any reference disclosed herein constitutes prior art. The 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.
Throughout this specification, the word "comprise" or "include", or variations thereof such as "comprises", "includes", "comprising" or "including" will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.
SUMMARY
In an exemplary embodiment there is provided a timber-working device, including:
a frame;
at least one pair of arms moveably connected to the frame, and configured to hold at least one stem to be processed by the timber-working device;
a sensing device having a sensing path extending between the frame and the at least one stem, and configured to output a signal indicative of a distance between the frame and a frame facing surface of the at least one stem; and at least one controller, configured to:
receive the signal indicating the distance between the frame and the frame facing surface of the at least one stem; and determine the number of stems currently held by the at least one pair of arms based at least in part on the signal.
In an exemplary embodiment there is provided a method, including:
holding at least one stem using at least one pair of arms moveably connected to a frame of a timber-working device;
outputting a signal indicative of a distance between the frame and a frame facing surface of the at least one stem from a sensing device having a sensing path extending between the frame and the at least one stem;
receiving the signal indicative of the distance between the frame and the frame facing surface of the at least one stem; and determining the number of stems currently held by the at least one pair of arms based at least in part on the signal.
OF STEMS HELD BY THE DEVICE
FIELD OF THE DISCLOSURE
The present invention relates to a timber-working device and method of operation.
BACKGROUND
It is well-known to mount timber-working devices, commonly referred to as forestry or harvester heads, to a carrier vehicle in order to perform a number of operations in connection with timber processing. These operations may include one, or a combination of, grappling and felling a standing tree, and processing one or more resulting stems by delimbing, debarking, and cutting those stems into logs.
The number of stems being concurrently processed heavily influences the manner in which measurements (such as diameter and length measurement) are to be interpreted ¨
for example when calculating the number and length of logs to be cut from a stem, or evaluating productivity such as volume and harvesting intensity (essentially the number of stems per land area unit). For accuracy, the number of stems needs to be known.
One method for accomplishing this would be to have the operator of the head manually input the number of stems being processed. However, it is generally desirable to reduce the burden on operators in order to reduce stress and fatigue, which can in turn lead to poor decision making with regard to control of the head and lost value to the forest owner.
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
No admission is made that any reference disclosed herein constitutes prior art. The 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.
Throughout this specification, the word "comprise" or "include", or variations thereof such as "comprises", "includes", "comprising" or "including" will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.
SUMMARY
In an exemplary embodiment there is provided a timber-working device, including:
a frame;
at least one pair of arms moveably connected to the frame, and configured to hold at least one stem to be processed by the timber-working device;
a sensing device having a sensing path extending between the frame and the at least one stem, and configured to output a signal indicative of a distance between the frame and a frame facing surface of the at least one stem; and at least one controller, configured to:
receive the signal indicating the distance between the frame and the frame facing surface of the at least one stem; and determine the number of stems currently held by the at least one pair of arms based at least in part on the signal.
In an exemplary embodiment there is provided a method, including:
holding at least one stem using at least one pair of arms moveably connected to a frame of a timber-working device;
outputting a signal indicative of a distance between the frame and a frame facing surface of the at least one stem from a sensing device having a sensing path extending between the frame and the at least one stem;
receiving the signal indicative of the distance between the frame and the frame facing surface of the at least one stem; and determining the number of stems currently held by the at least one pair of arms based at least in part on the signal.
2 In an exemplary embodiment, the sensing device includes a sensing member moveably connected to the frame, and configured to be brought into contact with the at least one stem.
In an exemplary embodiment, the sensing device includes a position sensor configured to output a signal indicative of a position of the sensing device relative to the frame. In an exemplary embodiment, the signal indicative of a distance between the frame and the frame facing surface of the at least one stem may be the signal indicative of the position of the sensing device relative to the frame.
In an exemplary embodiment there is provided a timber-working device, including:
a frame;
at least one pair of arms moveably connected to the frame, and configured to hold at least one stem to be processed by the timber-working device;
a sensing device moveably connected to the frame, and configured to be brought into contact with the at least one stem;
a position sensor configured to output a signal indicative of a position of the sensing device relative to the frame; and at least one controller, configured to:
receive the signal indicating the position of the sensing device; and determine the number of stems currently held by the at least one pair of arms based at least in part on the position of the sensing device.
In an exemplary embodiment there is provided a method, including:
holding at least one stem using at least one pair of arms moveably connected to a frame of a timber-working device;
moving a sensing device of the timber-working device into contact with the at least one stem;
outputting a signal indicative of a position of the sensing device relative to the frame from a position sensor;
receiving the signal indicative of a position of the sensing device; and determining the number of stems currently held by the at least one pair of arms based at least in part on the position of the sensing device.
In an exemplary embodiment, the sensing device includes a position sensor configured to output a signal indicative of a position of the sensing device relative to the frame. In an exemplary embodiment, the signal indicative of a distance between the frame and the frame facing surface of the at least one stem may be the signal indicative of the position of the sensing device relative to the frame.
In an exemplary embodiment there is provided a timber-working device, including:
a frame;
at least one pair of arms moveably connected to the frame, and configured to hold at least one stem to be processed by the timber-working device;
a sensing device moveably connected to the frame, and configured to be brought into contact with the at least one stem;
a position sensor configured to output a signal indicative of a position of the sensing device relative to the frame; and at least one controller, configured to:
receive the signal indicating the position of the sensing device; and determine the number of stems currently held by the at least one pair of arms based at least in part on the position of the sensing device.
In an exemplary embodiment there is provided a method, including:
holding at least one stem using at least one pair of arms moveably connected to a frame of a timber-working device;
moving a sensing device of the timber-working device into contact with the at least one stem;
outputting a signal indicative of a position of the sensing device relative to the frame from a position sensor;
receiving the signal indicative of a position of the sensing device; and determining the number of stems currently held by the at least one pair of arms based at least in part on the position of the sensing device.
3 The timber-working device may be a forestry or harvester head, and may be referred to as such throughout the specification. Forestry heads typically have the capacity to grapple and fell a standing tree, delimb and/or debark a felled stem, and cut the stem into logs.
However, a person skilled in the art should appreciate that the present invention may be used with other timber-working devices, and that reference to the timber-working device being a forestry head is not intended to be limiting.
In an exemplary embodiment the arms moveably connected to the frame may be drive arms.
The use of opposing drive arms, one on each side of a longitudinal axis of the frame of the head, is well known in the art. Each drive arm may include a drive mechanism at the end of the arm distal from its pivotal connection to the frame ¨ for example a rotary drive coupled with a feed wheel configured to be brought in contact with stem. The drive arms may be actuated, for example by hydraulic cylinders, to pivot relative to the frame in order to grapple the stem with the feed wheels. Rotation of the feed wheels may then drive or feed the stems along the longitudinal, or "feed", axis of the head.
In an exemplary embodiment the timber-working device may include delimb arms moveably connected to the frame. Delimb arms are known in the art, having sharpened edges to cut limbs from the stem as it is driven by the feed wheels.
In an exemplary embodiment, the timber-working device may include at least one angular position sensor configured to output a signal indicative of the angle of an associated arm relative to the frame. The angular position of at least one of the arms may be used in conjunction with the known geometry of the frame to determine the relative position of various points on the device, and thereby geometry of the stem(s) being grasped by the arms ¨ particularly diameter.
A diameter measurement using the arms may be the same for a single stem as for a combination of two stems held simultaneously by the arms. However, the combined profile of the outer surfaces of the two stems will be substantially different to that of a single stem ¨
substantially in the shape of a lemniscate as opposed to a circle. By obtaining an indication of the distance between the frame and the stems, inferences may be made regarding the profile of the stem(s) held by the arms, and subsequently the number thereof.
However, a person skilled in the art should appreciate that the present invention may be used with other timber-working devices, and that reference to the timber-working device being a forestry head is not intended to be limiting.
In an exemplary embodiment the arms moveably connected to the frame may be drive arms.
The use of opposing drive arms, one on each side of a longitudinal axis of the frame of the head, is well known in the art. Each drive arm may include a drive mechanism at the end of the arm distal from its pivotal connection to the frame ¨ for example a rotary drive coupled with a feed wheel configured to be brought in contact with stem. The drive arms may be actuated, for example by hydraulic cylinders, to pivot relative to the frame in order to grapple the stem with the feed wheels. Rotation of the feed wheels may then drive or feed the stems along the longitudinal, or "feed", axis of the head.
In an exemplary embodiment the timber-working device may include delimb arms moveably connected to the frame. Delimb arms are known in the art, having sharpened edges to cut limbs from the stem as it is driven by the feed wheels.
In an exemplary embodiment, the timber-working device may include at least one angular position sensor configured to output a signal indicative of the angle of an associated arm relative to the frame. The angular position of at least one of the arms may be used in conjunction with the known geometry of the frame to determine the relative position of various points on the device, and thereby geometry of the stem(s) being grasped by the arms ¨ particularly diameter.
A diameter measurement using the arms may be the same for a single stem as for a combination of two stems held simultaneously by the arms. However, the combined profile of the outer surfaces of the two stems will be substantially different to that of a single stem ¨
substantially in the shape of a lemniscate as opposed to a circle. By obtaining an indication of the distance between the frame and the stems, inferences may be made regarding the profile of the stem(s) held by the arms, and subsequently the number thereof.
4 It should be appreciated that the signal indicative of the distance between the frame and the frame facing surface of the at least one stem may not result from a direct measurement of said distance, but may be dependent thereon. Further discussion in this regard is outlined below.
It should be appreciated that determination of the number of stems currently held by the at least one pair of arms may include a determination that the number of stems is either one or more than one.
In an exemplary embodiment, the determination may be that the number of stems is either one, or two. More than two stems held by the head may present overall cross-sectional dimensions which correspond to a larger diameter single stem. While the processor may be configured to differentiate between individual counts, it is envisaged that in a number of applications the timber-working device may be rarely used to process three stems simultaneously. It may be unlikely that an operator will find that number of stems of a similar size in a stack of logs at the same time, being inefficient to purposefully search the stack for this occurrence. As such differentiation between a single stem or a number other than two stems, and two stems is envisaged as being sufficient in a number of applications.
In an exemplary embodiment, the arms may be substantially laterally centred on the longitudinal axis of the frame.
In an exemplary embodiment, the sensing path of the sensing device may be such that the point on the surface of the stem, or the position of the sensing device when in contact with the stem, is within a substantially laterally centralised region between the arms.
It is envisaged that this may be proximate to the point of contact between two stems held by the arms, providing the greatest differential in distance from the frame to the surface of the stem(s) in the cases of a single stem and two stems.
It should be appreciated that the width of the centralised region may be determined based on the capacity of the timber-working device with regard to the range of diameters of stems capable of being processed. There may be points across the profile of the surfaces of two stems which would be the same distance from the frame as in the case of a single stem with the same diameter reading from the arms.
Further, the width of the region may be selected in accordance with an allowable tolerance for false determination of more than one stem being held by the arms. Such a false determination may occur, for example, where a single stem is equivalent to two stems in terms of the dimension being measured. It is envisaged that such a single stem may rarely occur in forests in which the processing of multiple stems simultaneously is desired. As such, the impact of any inaccuracies in volume measurement or target length when processing single stems of that size may be tolerable in the context of total production by the timber-working device.
In an exemplary embodiment, the sensing member of the sensing device may be pivotally connected to the frame.
In an exemplary embodiment, the sensing member may include a measuring wheel arm.
Measuring wheel arms are known in the art for bringing a measuring wheel in contact with at least one stem held in the arms of a timber-working device. Rotation of the measuring wheel when in contact with the stem due to movement of the stem relative to the frame is measured, and a length measurement derived based on the known geometry of the wheel.
The sensing path of such a measuring wheel arm may be the arc through which the measuring wheel passes to be brought into contact with the stem. In one embodiment the measuring wheel arm may pivot in a plane perpendicular to a vertical centre plane aligned with the longitudinal axis of the frame. In another embodiment the measuring wheel arm may pivot in a plane parallel to, or aligned with, the vertical centre plane.
In an exemplary embodiment, the sensing member may be dedicated to obtaining the signal indicative of a distance between the frame and the frame facing surface of the at least one stem ¨ for example a sensing arm or a flap distinct from a measuring wheel arm.
In an exemplary embodiment, the sensing device may be configured to move linearly, rather than pivotally. For example, a measuring wheel may be mounted to a linear actuator for making contact with the stem.
In an exemplary embodiment, the position sensor may be configured to detect the presence of the sensing device, or a moveable member thereof, at a predetermined point relative to the frame. For example, the position sensor may be a proximity sensor configured to output a signal indicative of the sensing device reaching a predetermined position.
The positioning of such a proximity sensor may be determined based on a comparison of calculated geometries of single stems and double stems. For example, the position may be such that the distance along the sensing path to the point at which the proximity sensor senses the sensing device is at a threshold distance, beyond which the distance may be indicative of more than one stem being held by the head.
In an exemplary embodiment, the position sensor may be an angular position sensor. The angular position sensor may be any suitable means known to a person skilled in the art for determining rotation of the arms ¨ whether absolute or incremental. For example, the angular position sensor may be a rotary encoder.
For example, where the sensing device includes a measuring wheel arm pivotally connected to the frame, the angular movement of the arm about the pivot point may be measured using the angular position sensor as the measuring wheel moves along a curved sensing path.
This measurement, in conjunction with known geometries of the frame and arm, may be indicative of the linear distance between the frame and the at least one stem with which the measuring wheel is brought into contact.
It should be appreciated that the angular position sensor may not directly measure rotation of the arm (or other sensing device member). For example, the angular position sensor may be configured to output a signal indicative of the position of a linear actuator driving the pivoting arm. Reference to the position of the linear actuator should be understood to mean the position of a point on the actuator which may be used to determine the degree to which the actuator is extended. For example, the linear actuator may be a hydraulic cylinder including a linear position sensor. Various technologies are known in the art for achieving this ¨ for example operating using magnetostrictive principles, or Hall-Effect. Given known geometries of the timber-working device, the position of the actuator may be used to derive the angular position of the arm.
In an exemplary embodiment, the sensing device may be a contactless distance measurement device. Numerous sensing technologies are known in the art for contactless distance measurement ¨ for example optical, capacitive, or ultrasonic distance measurement sensors.
In an exemplary embodiment, determination of the number of stems currently held by the at least one pair of arms may be made at least in part based on a diameter measurement of the at least one stem.
As discussed above, there may be instances in which the output of the sensing device in the case of a single stem is the same as in the case of two stems. However, the profile of the single stem will be significantly different from that of two stems. For example, in terms of a diameter measurement obtained from the arms, the diameter of the single stem will be greater than the measurement from the combined stems.
Where the output of the sensing device is such that it may result from either a single stem or more than one stem, a comparison of the diameter measurement with a predetermined threshold value may be used to differentiate between the two scenarios to determine the number of stems.
The various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. In particular, they may be implemented or performed with one or more controllers having one or more processors, such as a microprocessor, or any other suitable means known in the art designed to perform the functions described.
The steps of a method, process, or algorithm and functions described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. If implemented in software, the functions may be stored as processor readable instructions or code on a tangible, non-transitory processor-readable medium ¨ for example Random Access Memory (RAM), flash memory, Read Only Memory (ROM), hard disks, a removable disk such as a CD ROM, or any other suitable storage medium known to a person skilled in the art. A
storage medium may be connected to the processor such that the processor can read information from, and write information to, the storage medium.
BRIEF DESCRIPTION OF DRAWINGS
Further aspects of the present invention 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. 1A is a side view of an exemplary timber-working system including, for example, a forestry head;
FIG. 1B is an elevated view of the forestry head;
FIG. 1C is an end view of components of the forestry head;
FIG. 2 is a diagrammatic view of an exemplary control system for the timber-working system;
FIG. 3A, 313 are end views of components of the forestry head in various stages of operating in accordance with an exemplary method of operation;
FIG. 4 is a line graph showing an exemplary relationship between the output of an exemplary sensing device, and the number of stems held by the exemplary forestry head;
FIG. 5 is a flowchart illustrating an exemplary method for determining the number of stems grasped by a forestry head.
DETAILED DESCRIPTION
FIG. 1A illustrates a timber-working system including a carrier 10 for use in forest harvesting. The carrier 10 includes an operator cab 12 from which an operator (not shown) controls the carrier 10. The carrier 10 further includes a boom assembly 14, to which a timber-working device in the form of a forestry head 16 is connected.
Connection of the head 16 to the boom assembly 14 includes a rotator 18, configured to rotate the head 16 about the generally vertical axis of rotation marked by dashed line 20. A
tilt bracket 22 further allows rotation of the head 16 between a prone position (as illustrated) and a standing position.
Referring to FIG. 1B, the head 16 includes a frame 24 to which the tilt bracket 22 of FIG. 1 is pivotally attached. Right hand (RH) and left hand (LH) delimb arms 26a and 26b are pivotally attached to the frame 24, as are opposing RH and LH feed arms 28a and 28b. RH
and LH feed wheels 30a and 30b are attached to RH and LH feed arms 28a and 28b respectively, which together with RH and LH frame-mounted feed wheels 32a and 32b may be controlled to feed one or more stems (not illustrated) along a longitudinal feed axis 34 of the head 16. Feed wheels 30a, 30b, 32a and 32b may collectively be referred to as the 'feed mechanism.' A measuring wheel 36 may be used to measure the length of the stem as it passes (further description of the measuring wheel 36 is outlined below with reference to FIG. 1C
A main chainsaw 38, and a topping chainsaw 40, are attached to the frame 24.
The main saw 38 is typically used to fell a tree when the head 16 is in a harvesting position, and to buck stems into logs in the processing position of the head 16 (as seen in FIG. 1). The topping saw 40 may be used to cut off a small-diameter top portion of the stem(s) to maximize the value recovery of the trees.
FIG. 1C illustrates a measuring wheel arm 42 pivotally connected to frame 24 (not shown in FIG. 1C) at a first end, with the measuring wheel 36 positioned at the distal end. A linear actuator in the form of measuring wheel hydraulic cylinder 44 is connected between the measuring wheel arm 42 and the frame 24, extension and retraction of which moves the measuring wheel 36 along the path indicated by dashed line 46.
The measuring wheel arm 42 may be positioned and/or configured such that the sensing path 46 passes through a sensing window 48 for the range of stem diameters the head 16 is configured to process. The width of the sensing window 48 relative to the feed axis 34 (not shown in FIG. 1C, but substantially centred between the feed wheels 32a and 32b) may be selected based on the intended stem diameters to be processed, and allowable tolerances for the range of cases in which single stems may be interpreted as two stems.
In an exemplary embodiment, a position sensor 50a is positioned such that its output signal indicates when the measuring wheel arms 42 has moved away from the position sensor 50a by a predetermined extent. The position sensor 50a may detect the arm 42 itself, or a target 50b mounted to the arm 42.
In an exemplary embodiment, a contactless distance measurement sensor 52 (for example an optical distance sensor or an ultrasonic distance sensor, as known in the art) may be positioned such that its sensing path projects into the sensing window 48. In such an embodiment the angle or position of the measuring arm 42 may not be required.
The various operations of the head 16 may be controlled by the operator using hand and foot controls as known in the art. Further, certain automated functions of the harvester head 16 may be controlled by an electronic control system 200 as shown by FIG. 2.
The control system 200 includes one or more electronic controllers, each controller including a processor and memory having stored therein instructions which, when executed by the processor, causes the processor to perform the various operations of the controller.
For example, the control system 200 includes a first controller 202 on board the carrier 10 and a second controller 204 on board the head 16. The controllers 202, 204 are connected to one another via a communications bus 206 (e.g., a CAN bus, or a wireless link).
A human operator operates an operator input device 208, for example hand and foot controls, located at the operator's cab 12 of the carrier 10 to control the head 16. Details of operation are output to an output device 210 ¨ for example a monitor. Certain automated functions may be controlled by first controller 202 and/or second controller 204.
The system 200 includes angular position sensors ¨ for example at least one delimb rotation sensor 212a mounted to one or both of delimb arms 26a or 26b, and/or at least one feed rotation sensor 212b mounted to one or both of feed arms 28a or 28b ¨ each configured to output a signal indicative of the angular position of the associated arm for transmission to first controller 202 via second controller 204 and bus 206. This arm angle may be used to determine diameter of the stem(s) held by the head 16, as known in the art.
The head 16 has a number of valves 214 arranged, for example, in a valve block and coupled electrically to the second controller 204 so as to be under its control. The valves 214 include, for example, delimb arm valves 216 configured to control pivotal movement of the delimb arms 26a and 26b, and feed arm valves 218 configured to control pivotal movement of the feed arms 28a and 28b. The valves 214 also include measuring arm valves 220, configured to control movement of the measuring wheel arm 42.
Depending on the embodiment, the system 200 may also include one, or a combination of, position sensor 50a, contactless distance measurement sensor 52, and measuring arm angle sensor 222. The measuring arm angle sensor 222 may be a rotary angle sensor with an output measuring pivotal movement, or a linear sensor associated with measuring wheel hydraulic cylinder 44, the output of which may be used to infer the angle of rotation.
FIG. 3A illustrates a case in which the positions of the feed arm wheels 30a and 30b (and thus the diameter measurement) are the same in the two cases of a single stem 300, and twin stems 302a and 302b (each of a smaller actual diameter than stem 300). It may be seen that the distance from a fixed point 304 relative to the frame to the respective surfaces is different in both cases.
Referring to FIG. 3B, the positions of the feed arm wheels 30a and 30b when holding a single stem 306 are shown in dashed line. It should be appreciated that the diameter measurement will be significantly different to that of the case of holding twin stems 308a and 308b (which have smaller diameters than stem 306). However, in some cases the difference between the distances from the fixed point 304 to the respective surfaces of the stems may be relatively small, or substantially the same.
Referring to FIG. 4, plot 400 shows the diameter of a single stem held by the head 16 plotted against the angle of rotation of the measuring wheel arm 42 from horizontal to bring the measuring wheel 34 into contact with the stem. Plot 402 shows the individual diameter of twin stems plotted against measuring wheel arm 42. It may be seen that there is a window 404 of values in which the angle of the measuring wheel arm 42 overlaps between the single stem 400 and twin stem 402 cases.
In an exemplary embodiment, every measuring wheel arm 42 angle measurement above the beginning of the window 404 may be used to assume that two stems are held by the head 16. It is envisaged that the diameter of single stems within the window 404 may occur infrequently within forests in which it is desired to process multiple stems simultaneously, and therefore have a low impact on the overall accuracy of the head 16.
In an exemplary embodiment, the diameter measurement of the delimb arms 26a and 26b or feed arms 28a and 28b may be used to differentiate between single and two stem cases within the window 404. It should be appreciated that the use of the diameter measurement may always be used, within the window 404, or from the beginning of the window 404.
Plot 406 illustrates the error introduced with regard to diameter measurement when processing a single stem using an assumption that two stems are held by the head 16 ¨ i.e.
basing calculations for recorded diameter values on algorithms specified for two stems. The diameter measurements associated with plot 406 could be used as a baseline for the threshold diameter values, although it should be appreciated that this is not intended to be limiting.
The control system 200 is configured to implement method 500 of FIG. 5, which will be described with reference to foregoing description of the figures.
In step 502, a human operator operates the operator input device 208 to grasp one or more stems with the delimb arms 26a and 26b, such that the stem(s) is held against the frame-mounted feed wheels 32a and 32b ¨ as illustrated in FIG. 3A, for example.
In step 504 the second controller 208 operates a sensing device to an indication of the distance from the frame 24 to the surface of the stem(s).
In an embodiment, contactless distance measurement sensor 52 obtains a distance reading and outputs a signal indicative of same.
In an embodiment, measuring arm valves 220 are controlled to rotate the measuring wheel arm 42 such that the measuring wheel 36 is brought in contact with the stem.
In an embodiment, the signal output by position sensor 50a indicates whether the angle of the measuring wheel arm 42 is such that it is beyond the beginning of window 404.
In another embodiment, the signal output by measure arm angle sensor 222 indicates the angle of rotation.
In step 506, the second controller 208 transmits the signal to the first controller 202, where it is received and processed to determine the number of stems held by the head.
In an embodiment, if the signal indicative of the distance from the frame 24 to the surface of the stem(s) is above a threshold value (for example equivalent to the beginning of window 404), the first controller 202 may determine that two stems are held by the head 16, and base further processing decisions on this.
In an embodiment, the second controller 208 may also transmit the output of either (or both) of the delimb rotation sensor 212a and feed rotation sensor 212b to the first controller 202.
In such an embodiment, the first controller 202 may also compare the diameter value with a threshold diameter value associated with the value of the received signal indicative of the distance from the frame 24 to the surface of the stem(s), to determine whether a single stem or two stems are held by the head 16.
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 of endeavour in any country in the world.
Embodiments described herein 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.
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 made without departing from the scope of the disclosure and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the present invention.
Embodiments 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 as defined in the appended claims.
It should be appreciated that determination of the number of stems currently held by the at least one pair of arms may include a determination that the number of stems is either one or more than one.
In an exemplary embodiment, the determination may be that the number of stems is either one, or two. More than two stems held by the head may present overall cross-sectional dimensions which correspond to a larger diameter single stem. While the processor may be configured to differentiate between individual counts, it is envisaged that in a number of applications the timber-working device may be rarely used to process three stems simultaneously. It may be unlikely that an operator will find that number of stems of a similar size in a stack of logs at the same time, being inefficient to purposefully search the stack for this occurrence. As such differentiation between a single stem or a number other than two stems, and two stems is envisaged as being sufficient in a number of applications.
In an exemplary embodiment, the arms may be substantially laterally centred on the longitudinal axis of the frame.
In an exemplary embodiment, the sensing path of the sensing device may be such that the point on the surface of the stem, or the position of the sensing device when in contact with the stem, is within a substantially laterally centralised region between the arms.
It is envisaged that this may be proximate to the point of contact between two stems held by the arms, providing the greatest differential in distance from the frame to the surface of the stem(s) in the cases of a single stem and two stems.
It should be appreciated that the width of the centralised region may be determined based on the capacity of the timber-working device with regard to the range of diameters of stems capable of being processed. There may be points across the profile of the surfaces of two stems which would be the same distance from the frame as in the case of a single stem with the same diameter reading from the arms.
Further, the width of the region may be selected in accordance with an allowable tolerance for false determination of more than one stem being held by the arms. Such a false determination may occur, for example, where a single stem is equivalent to two stems in terms of the dimension being measured. It is envisaged that such a single stem may rarely occur in forests in which the processing of multiple stems simultaneously is desired. As such, the impact of any inaccuracies in volume measurement or target length when processing single stems of that size may be tolerable in the context of total production by the timber-working device.
In an exemplary embodiment, the sensing member of the sensing device may be pivotally connected to the frame.
In an exemplary embodiment, the sensing member may include a measuring wheel arm.
Measuring wheel arms are known in the art for bringing a measuring wheel in contact with at least one stem held in the arms of a timber-working device. Rotation of the measuring wheel when in contact with the stem due to movement of the stem relative to the frame is measured, and a length measurement derived based on the known geometry of the wheel.
The sensing path of such a measuring wheel arm may be the arc through which the measuring wheel passes to be brought into contact with the stem. In one embodiment the measuring wheel arm may pivot in a plane perpendicular to a vertical centre plane aligned with the longitudinal axis of the frame. In another embodiment the measuring wheel arm may pivot in a plane parallel to, or aligned with, the vertical centre plane.
In an exemplary embodiment, the sensing member may be dedicated to obtaining the signal indicative of a distance between the frame and the frame facing surface of the at least one stem ¨ for example a sensing arm or a flap distinct from a measuring wheel arm.
In an exemplary embodiment, the sensing device may be configured to move linearly, rather than pivotally. For example, a measuring wheel may be mounted to a linear actuator for making contact with the stem.
In an exemplary embodiment, the position sensor may be configured to detect the presence of the sensing device, or a moveable member thereof, at a predetermined point relative to the frame. For example, the position sensor may be a proximity sensor configured to output a signal indicative of the sensing device reaching a predetermined position.
The positioning of such a proximity sensor may be determined based on a comparison of calculated geometries of single stems and double stems. For example, the position may be such that the distance along the sensing path to the point at which the proximity sensor senses the sensing device is at a threshold distance, beyond which the distance may be indicative of more than one stem being held by the head.
In an exemplary embodiment, the position sensor may be an angular position sensor. The angular position sensor may be any suitable means known to a person skilled in the art for determining rotation of the arms ¨ whether absolute or incremental. For example, the angular position sensor may be a rotary encoder.
For example, where the sensing device includes a measuring wheel arm pivotally connected to the frame, the angular movement of the arm about the pivot point may be measured using the angular position sensor as the measuring wheel moves along a curved sensing path.
This measurement, in conjunction with known geometries of the frame and arm, may be indicative of the linear distance between the frame and the at least one stem with which the measuring wheel is brought into contact.
It should be appreciated that the angular position sensor may not directly measure rotation of the arm (or other sensing device member). For example, the angular position sensor may be configured to output a signal indicative of the position of a linear actuator driving the pivoting arm. Reference to the position of the linear actuator should be understood to mean the position of a point on the actuator which may be used to determine the degree to which the actuator is extended. For example, the linear actuator may be a hydraulic cylinder including a linear position sensor. Various technologies are known in the art for achieving this ¨ for example operating using magnetostrictive principles, or Hall-Effect. Given known geometries of the timber-working device, the position of the actuator may be used to derive the angular position of the arm.
In an exemplary embodiment, the sensing device may be a contactless distance measurement device. Numerous sensing technologies are known in the art for contactless distance measurement ¨ for example optical, capacitive, or ultrasonic distance measurement sensors.
In an exemplary embodiment, determination of the number of stems currently held by the at least one pair of arms may be made at least in part based on a diameter measurement of the at least one stem.
As discussed above, there may be instances in which the output of the sensing device in the case of a single stem is the same as in the case of two stems. However, the profile of the single stem will be significantly different from that of two stems. For example, in terms of a diameter measurement obtained from the arms, the diameter of the single stem will be greater than the measurement from the combined stems.
Where the output of the sensing device is such that it may result from either a single stem or more than one stem, a comparison of the diameter measurement with a predetermined threshold value may be used to differentiate between the two scenarios to determine the number of stems.
The various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. In particular, they may be implemented or performed with one or more controllers having one or more processors, such as a microprocessor, or any other suitable means known in the art designed to perform the functions described.
The steps of a method, process, or algorithm and functions described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. If implemented in software, the functions may be stored as processor readable instructions or code on a tangible, non-transitory processor-readable medium ¨ for example Random Access Memory (RAM), flash memory, Read Only Memory (ROM), hard disks, a removable disk such as a CD ROM, or any other suitable storage medium known to a person skilled in the art. A
storage medium may be connected to the processor such that the processor can read information from, and write information to, the storage medium.
BRIEF DESCRIPTION OF DRAWINGS
Further aspects of the present invention 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. 1A is a side view of an exemplary timber-working system including, for example, a forestry head;
FIG. 1B is an elevated view of the forestry head;
FIG. 1C is an end view of components of the forestry head;
FIG. 2 is a diagrammatic view of an exemplary control system for the timber-working system;
FIG. 3A, 313 are end views of components of the forestry head in various stages of operating in accordance with an exemplary method of operation;
FIG. 4 is a line graph showing an exemplary relationship between the output of an exemplary sensing device, and the number of stems held by the exemplary forestry head;
FIG. 5 is a flowchart illustrating an exemplary method for determining the number of stems grasped by a forestry head.
DETAILED DESCRIPTION
FIG. 1A illustrates a timber-working system including a carrier 10 for use in forest harvesting. The carrier 10 includes an operator cab 12 from which an operator (not shown) controls the carrier 10. The carrier 10 further includes a boom assembly 14, to which a timber-working device in the form of a forestry head 16 is connected.
Connection of the head 16 to the boom assembly 14 includes a rotator 18, configured to rotate the head 16 about the generally vertical axis of rotation marked by dashed line 20. A
tilt bracket 22 further allows rotation of the head 16 between a prone position (as illustrated) and a standing position.
Referring to FIG. 1B, the head 16 includes a frame 24 to which the tilt bracket 22 of FIG. 1 is pivotally attached. Right hand (RH) and left hand (LH) delimb arms 26a and 26b are pivotally attached to the frame 24, as are opposing RH and LH feed arms 28a and 28b. RH
and LH feed wheels 30a and 30b are attached to RH and LH feed arms 28a and 28b respectively, which together with RH and LH frame-mounted feed wheels 32a and 32b may be controlled to feed one or more stems (not illustrated) along a longitudinal feed axis 34 of the head 16. Feed wheels 30a, 30b, 32a and 32b may collectively be referred to as the 'feed mechanism.' A measuring wheel 36 may be used to measure the length of the stem as it passes (further description of the measuring wheel 36 is outlined below with reference to FIG. 1C
A main chainsaw 38, and a topping chainsaw 40, are attached to the frame 24.
The main saw 38 is typically used to fell a tree when the head 16 is in a harvesting position, and to buck stems into logs in the processing position of the head 16 (as seen in FIG. 1). The topping saw 40 may be used to cut off a small-diameter top portion of the stem(s) to maximize the value recovery of the trees.
FIG. 1C illustrates a measuring wheel arm 42 pivotally connected to frame 24 (not shown in FIG. 1C) at a first end, with the measuring wheel 36 positioned at the distal end. A linear actuator in the form of measuring wheel hydraulic cylinder 44 is connected between the measuring wheel arm 42 and the frame 24, extension and retraction of which moves the measuring wheel 36 along the path indicated by dashed line 46.
The measuring wheel arm 42 may be positioned and/or configured such that the sensing path 46 passes through a sensing window 48 for the range of stem diameters the head 16 is configured to process. The width of the sensing window 48 relative to the feed axis 34 (not shown in FIG. 1C, but substantially centred between the feed wheels 32a and 32b) may be selected based on the intended stem diameters to be processed, and allowable tolerances for the range of cases in which single stems may be interpreted as two stems.
In an exemplary embodiment, a position sensor 50a is positioned such that its output signal indicates when the measuring wheel arms 42 has moved away from the position sensor 50a by a predetermined extent. The position sensor 50a may detect the arm 42 itself, or a target 50b mounted to the arm 42.
In an exemplary embodiment, a contactless distance measurement sensor 52 (for example an optical distance sensor or an ultrasonic distance sensor, as known in the art) may be positioned such that its sensing path projects into the sensing window 48. In such an embodiment the angle or position of the measuring arm 42 may not be required.
The various operations of the head 16 may be controlled by the operator using hand and foot controls as known in the art. Further, certain automated functions of the harvester head 16 may be controlled by an electronic control system 200 as shown by FIG. 2.
The control system 200 includes one or more electronic controllers, each controller including a processor and memory having stored therein instructions which, when executed by the processor, causes the processor to perform the various operations of the controller.
For example, the control system 200 includes a first controller 202 on board the carrier 10 and a second controller 204 on board the head 16. The controllers 202, 204 are connected to one another via a communications bus 206 (e.g., a CAN bus, or a wireless link).
A human operator operates an operator input device 208, for example hand and foot controls, located at the operator's cab 12 of the carrier 10 to control the head 16. Details of operation are output to an output device 210 ¨ for example a monitor. Certain automated functions may be controlled by first controller 202 and/or second controller 204.
The system 200 includes angular position sensors ¨ for example at least one delimb rotation sensor 212a mounted to one or both of delimb arms 26a or 26b, and/or at least one feed rotation sensor 212b mounted to one or both of feed arms 28a or 28b ¨ each configured to output a signal indicative of the angular position of the associated arm for transmission to first controller 202 via second controller 204 and bus 206. This arm angle may be used to determine diameter of the stem(s) held by the head 16, as known in the art.
The head 16 has a number of valves 214 arranged, for example, in a valve block and coupled electrically to the second controller 204 so as to be under its control. The valves 214 include, for example, delimb arm valves 216 configured to control pivotal movement of the delimb arms 26a and 26b, and feed arm valves 218 configured to control pivotal movement of the feed arms 28a and 28b. The valves 214 also include measuring arm valves 220, configured to control movement of the measuring wheel arm 42.
Depending on the embodiment, the system 200 may also include one, or a combination of, position sensor 50a, contactless distance measurement sensor 52, and measuring arm angle sensor 222. The measuring arm angle sensor 222 may be a rotary angle sensor with an output measuring pivotal movement, or a linear sensor associated with measuring wheel hydraulic cylinder 44, the output of which may be used to infer the angle of rotation.
FIG. 3A illustrates a case in which the positions of the feed arm wheels 30a and 30b (and thus the diameter measurement) are the same in the two cases of a single stem 300, and twin stems 302a and 302b (each of a smaller actual diameter than stem 300). It may be seen that the distance from a fixed point 304 relative to the frame to the respective surfaces is different in both cases.
Referring to FIG. 3B, the positions of the feed arm wheels 30a and 30b when holding a single stem 306 are shown in dashed line. It should be appreciated that the diameter measurement will be significantly different to that of the case of holding twin stems 308a and 308b (which have smaller diameters than stem 306). However, in some cases the difference between the distances from the fixed point 304 to the respective surfaces of the stems may be relatively small, or substantially the same.
Referring to FIG. 4, plot 400 shows the diameter of a single stem held by the head 16 plotted against the angle of rotation of the measuring wheel arm 42 from horizontal to bring the measuring wheel 34 into contact with the stem. Plot 402 shows the individual diameter of twin stems plotted against measuring wheel arm 42. It may be seen that there is a window 404 of values in which the angle of the measuring wheel arm 42 overlaps between the single stem 400 and twin stem 402 cases.
In an exemplary embodiment, every measuring wheel arm 42 angle measurement above the beginning of the window 404 may be used to assume that two stems are held by the head 16. It is envisaged that the diameter of single stems within the window 404 may occur infrequently within forests in which it is desired to process multiple stems simultaneously, and therefore have a low impact on the overall accuracy of the head 16.
In an exemplary embodiment, the diameter measurement of the delimb arms 26a and 26b or feed arms 28a and 28b may be used to differentiate between single and two stem cases within the window 404. It should be appreciated that the use of the diameter measurement may always be used, within the window 404, or from the beginning of the window 404.
Plot 406 illustrates the error introduced with regard to diameter measurement when processing a single stem using an assumption that two stems are held by the head 16 ¨ i.e.
basing calculations for recorded diameter values on algorithms specified for two stems. The diameter measurements associated with plot 406 could be used as a baseline for the threshold diameter values, although it should be appreciated that this is not intended to be limiting.
The control system 200 is configured to implement method 500 of FIG. 5, which will be described with reference to foregoing description of the figures.
In step 502, a human operator operates the operator input device 208 to grasp one or more stems with the delimb arms 26a and 26b, such that the stem(s) is held against the frame-mounted feed wheels 32a and 32b ¨ as illustrated in FIG. 3A, for example.
In step 504 the second controller 208 operates a sensing device to an indication of the distance from the frame 24 to the surface of the stem(s).
In an embodiment, contactless distance measurement sensor 52 obtains a distance reading and outputs a signal indicative of same.
In an embodiment, measuring arm valves 220 are controlled to rotate the measuring wheel arm 42 such that the measuring wheel 36 is brought in contact with the stem.
In an embodiment, the signal output by position sensor 50a indicates whether the angle of the measuring wheel arm 42 is such that it is beyond the beginning of window 404.
In another embodiment, the signal output by measure arm angle sensor 222 indicates the angle of rotation.
In step 506, the second controller 208 transmits the signal to the first controller 202, where it is received and processed to determine the number of stems held by the head.
In an embodiment, if the signal indicative of the distance from the frame 24 to the surface of the stem(s) is above a threshold value (for example equivalent to the beginning of window 404), the first controller 202 may determine that two stems are held by the head 16, and base further processing decisions on this.
In an embodiment, the second controller 208 may also transmit the output of either (or both) of the delimb rotation sensor 212a and feed rotation sensor 212b to the first controller 202.
In such an embodiment, the first controller 202 may also compare the diameter value with a threshold diameter value associated with the value of the received signal indicative of the distance from the frame 24 to the surface of the stem(s), to determine whether a single stem or two stems are held by the head 16.
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 of endeavour in any country in the world.
Embodiments described herein 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.
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 made without departing from the scope of the disclosure and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the present invention.
Embodiments 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 as defined in the appended claims.
Claims (15)
1. A timber-working device, including:
a frame;
at least one pair of arms moveably connected to the frame, and configured to hold at least one stem to be processed by the timber-working device;
a sensing device having a sensing path extending between the frame and the at least one stem, and configured to output a signal indicative of a distance between the frame and a frame facing surface of the at least one stem; and at least one controller, configured to:
receive the signal indicating the distance between the frame and the frame facing surface of the at least one stem; and determine whether the number of stems currently held by the at least one pair of arms is two, or a number other than two, based at least in part on the signal.
a frame;
at least one pair of arms moveably connected to the frame, and configured to hold at least one stem to be processed by the timber-working device;
a sensing device having a sensing path extending between the frame and the at least one stem, and configured to output a signal indicative of a distance between the frame and a frame facing surface of the at least one stem; and at least one controller, configured to:
receive the signal indicating the distance between the frame and the frame facing surface of the at least one stem; and determine whether the number of stems currently held by the at least one pair of arms is two, or a number other than two, based at least in part on the signal.
2. The timber-working device of claim 1, wherein the sensing device includes a sensing member moveably connected to the frame, and configured to be brought into contact with the at least one stem.
3. The timber-working device of claim 2, wherein the sensing member is a measuring wheel arm.
4. The timber-working device of claim 2 or claim 3, wherein the sensing device includes a position sensor configured to output a signal indicative of a position of the sensing member relative to the frame.
5. The timber-working device of claim 4, wherein the position sensor is a proximity sensor configured to output a signal indicative of the sensing member moving beyond a predetermined position.
6. The timber-working device of claim 4, wherein the position sensor is an angular position sensor.
7. The timber-working device of any one of claims 4 to 6, wherein the signal indicative of the position of the sensing member relative to the frame is the signal indicative of a distance between the frame and the frame facing surface of the at least one stem.
8. The timber-working device of claim 1, wherein the sensing device is a contactless distance measurement device.
9. The timber-working device of any one of claims 1 to 8, wherein the at least one pair of arms are substantially laterally centred on a longitudinal axis of the frame.
10. The timber-working device of claim 9, wherein the sensing path of the sensing device is such that a sensed surface of the at least one stem is within a substantially laterally centralised region between the at least one pair of arms.
11. The timber-working device of any one of claims 1 to 10, wherein the controller is configured to determine the number of stems currently held by the at least one pair of arms at least in part based on a diameter measurement of the at least one stem.
12. The timber-working devi of any one of claims 1 to 11, including at least one arm angle sensor configured to output a signal indicative of the angle of an associated arm relative to the frame.
13. A method, including:
holding at least one stem using at least one pair of arms moveably connected to a frame of a timber-working device;
outputting a signal indicative of a distance between the frame and a frame facing surface of the at least one stem from a sensing device having a sensing path extending between the frame and the at least one stem;
receiving the signal indicative of the distance between the frame and the frame facing surface of the at least one stem; and determining whether the number of stems currently held by the at least one pair of arms is two, or a number other than two, based at least in part on the signal.
holding at least one stem using at least one pair of arms moveably connected to a frame of a timber-working device;
outputting a signal indicative of a distance between the frame and a frame facing surface of the at least one stem from a sensing device having a sensing path extending between the frame and the at least one stem;
receiving the signal indicative of the distance between the frame and the frame facing surface of the at least one stem; and determining whether the number of stems currently held by the at least one pair of arms is two, or a number other than two, based at least in part on the signal.
14. The method of claim 13, wherein the signal indicative of the distance between the frame and the frame facing surface of the at least one stem is indicative of an angle of a measuring wheel arm of the timber-working device relative to the frame.
15. The method of claim 13 or claim 14, wherein determining the number of stems currently held by the at least one pair of arms is based in part on a diameter measurement of the at least one stem.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NZ705339A NZ705339A (en) | 2015-02-27 | 2015-02-27 | A timber-working device and method of determining the number of stems held by the device |
| NZ705339 | 2015-02-27 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2921720A1 CA2921720A1 (en) | 2016-08-27 |
| CA2921720C true CA2921720C (en) | 2023-08-01 |
Family
ID=56132568
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2921720A Active CA2921720C (en) | 2015-02-27 | 2016-02-23 | A timber-working device and method of determining the number of stems held by the device |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2921720C (en) |
| NZ (1) | NZ705339A (en) |
-
2015
- 2015-02-27 NZ NZ705339A patent/NZ705339A/en unknown
-
2016
- 2016-02-23 CA CA2921720A patent/CA2921720C/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CA2921720A1 (en) | 2016-08-27 |
| NZ705339A (en) | 2016-05-27 |
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