CA2904241C

CA2904241C - A timber-working device and method of operation

Info

Publication number: CA2904241C
Application number: CA2904241A
Authority: CA
Inventors: Douglas Craig Swinyard
Original assignee: Waratah NZ Ltd
Current assignee: Waratah NZ Ltd
Priority date: 2013-12-02
Filing date: 2014-12-02
Publication date: 2022-05-03
Anticipated expiration: 2034-12-02
Also published as: WO2015084183A3; CA2904241A1; NZ618435A; WO2015084183A2

Abstract

A timber-working device, including a frame (24) having a feed axis (34), and a drive system configured to position a first stem (300) on a first side of the feed axis (34), and a second stem (302) on a second side of the feed axis (34). The timber-working device includes a first end sensor (42) having a first sensing region extending into the first side of the feed axis (34), and configured to output a signal indicative of the presence of an end of the first stem (300) within the first sensing region. The timber-working device includes a second end sensor (42) having a second sensing region extending into the second side of the feed axis (34), and configured to output a signal indicative of the presence of an end of the second stem (302) within the second sensing region.

Description

A TIMBER-WORKING DEVICE AND METHOD OF OPERATION
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, delimbing a felled stem, debarking the stem, and cutting the stem into logs (known as bucking) ¨ commonly using at least one chainsaw.
Feeding the stem along its length relative to the head is typically achieved using arm mounted rotary drives having a feed wheel at the end of opposing drive arms configured to grasp the stem, together with at least one frame mounted feed wheel.
Once a tree has been felled, or on picking up a previously felled stem, the first step in processing is usually to feed the stem through to one end. The accuracy of this end finding step influences the maximum length and thus value which may be obtained from a stem.
Performing this step manually takes time and causes operator stress and fatigue, which may in turn lead to poor decision making with regard to control of the head and lost value to the forest owner. As such, when processing a single stem it is known to automatically determine when an end has been reached using a photocell to detect an end of the stern as it passes.
Some forestry heads are configured for processing multiple stems at a time, in which stems may be fed through the head independently from each other, to align them before bucking.
However, such heads are not capable of automatically finding the independent ends of the stems. This requires the operator to manually align the ends of the stems, or perform a cut with the saw which is potentially wasteful.
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

Date Recue/Date Received 2021-06-04 All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The 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
According to another aspect of the present invention there is provided a timber-working device, including:
a frame, including a feed axis;
a drive system configured to position a first stem on a first side of the feed axis, and a second stem on a second side of the feed axis;
a first end sensor having a first sensing region extending into the first side of the feed axis, and configured to output a signal indicative of the presence of an end of the first stem within the first sensing region; and a second end sensor having a second sensing region extending into the second side of the feed axis, and configured to output a signal indicative of the presence of an end of the second stem within the second sensing region.
In an embodiment the drive system may be configured to independently feed the first stem and second stem along the feed axis.
The timber-working device may include at least one controller configured to:
control the drive system to feed the first stem and the second stem along the feed axis;
receive the signal from the first end sensor indicative of the end of the first stem being present within the first sensing region;

2

3 PCT/NZ2014/000239 control the drive system to align the end of the first stem with a predetermined point along the feed axis;
receive the signal from the second end sensor indicative of the end of the second stem being present within the second sensing region; and control the second drive arm to align the end of the second length of material with the predetermined point along the feed axis.
According to an embodiment of the present invention there is provided a method for aligning a first stem and a second stem, the method including the steps of:
positioning the first stem on a first side of a feed axis, and the second stem on a second side of the feed axis;
feeding the first stem and the second stem along the feed axis;
receiving a signal from a first end sensor having a first sensing region extending into the first side of the feed axis, the signal being indicative of the end of the first stem being present within the first sensing region;
aligning the first stem with a predetermined point along the feed axis;
receiving a signal from a second end sensor having a second sensing region extending into the second side of the feed axis, the signal being indicative of the end of the second stem being present within the second sensing region; and aligning the second stem with the predetermined point along the feed axis.
According to another aspect of the present invention there is provided an article of manufacture having computer storage medium storing computer readable program code executable by a computer to implement a method for aligning a first stem and a second stem, the code including:
computer readable program code positioning the first stem on a first side of a feed axis, and the second stem on a second side of the feed axis;
computer readable program code feeding the first stem and the second stem along the feed axis;
computer readable program code receiving a signal from a first end sensor having a first sensing region extending into the first side of the feed axis, the signal being indicative of the end of the first stem being present within the first sensing region;
computer readable program code aligning the first stem with a predetermined point along the feed axis;

computer readable program code receiving a signal from a second end sensor having a second sensing region extending into the second side of the feed axis, the signal being indicative of the end of the second stem being present within the second sensing region; and computer readable program code aligning the second stem with the predetermined point along the feed axis.
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 to timber-working devices, and that reference to the timber-working device being a forestry head is not intended to be limiting.
The drive system may include a first drive mechanism located on the first side of the feed axis, and a second drive mechanism located on the other side of the feed axis. The first drive mechanism may be operable independently from the second drive mechanism.
One well known system for forestry heads uses opposing drive arms, one on each side of the feed axis. Each drive arm may include a feed wheel configured to be brought in contact with stem. The arms may be driven, for example by hydraulic cylinders, to pivot relative to the frame of the device in order to grapple the stem with the feed wheels. The feed wheels may each connected to a rotary drive such that they may be used to drive or feed the stems along the feed axis of the head.
The drive system may further include one or more frame mounted feed wheels.
The drive system may include a frame mounted feed wheel on either side of the feed axis, which may be controlled independently to each other. Where two stems are grasped by the drive arms, these frame mounted wheels may be controlled together with those of the respective drive arms to independently control the relative positions of the two stems along the feed axis.
It should be appreciated that this is not intended to be limiting, and the apparatus may include only a single frame mounted feed wheel, for example aligned with the feed axis. Where the apparatus is processing two stems and it is desirable to feed the stems independently, the frame mounted wheel may be locked or permitted to spin freely, with the arm mounted feed wheels used to control feeding.
The timber-working device may include a distance measuring device. For example, the distance measuring device may be a measuring wheel as known in the art. The measuring wheel may be brought into contact with a stem, and an encoder used to determine its revolutions and therefore distance travelled. In another embodiment, distance may be determined on the basis of the runtime of the drive system.

4 The timber-working device may include a cutting device ¨ for example at least one saw. It is known for forestry heads to include a main chainsaw which is primarily used for the felling and cross cutting of stems. Further, some forestry heads may include a secondary or topping chainsaw. The topping saw is typically of a lower specification than the main saw, and used primarily during processing once a tree is felled.
Reference to the cutting device being a chainsaw is not intended to be limiting, as the saw may take other forms ¨ for example a disc saw. Further, the cutting device may take other forms known in the art, for example a shear.
The predetermined point along the feed axis may be a cutting position at which the stems are to be severed by the cutting device. As such, embodiments of the present invention may include the method step of cutting the stems with the cutting device once they are aligned.
The cutting position may be set, for example, to create clean ends on the stems before further processing ¨ in which case the ends of the stem would be aligned with a position a short distance past the cutting device.
Alternatively, the cutting position may be that required to produce logs of a desired length from the stems ¨ in which case the stems may be fed through the head by a measured distance.
The end sensors may be any suitable means known to a person skilled in the art for determining the location of an end or edge of a length of material. It should be appreciated that the predetermined point with which the stems are to be aligned may be the position of the sensing regions of the end sensors.
In an embodiment the end sensors may be non-contact sensors. Components used in or with forestry heads are generally exposed to harsh operating conditions ¨ both in terms of the shock and vibration generated during use and operation of the head, and also the high levels of dust, dirt, and debris present in the surrounding environment. In such an environment it may be desirable to reduce the number of moving parts and mechanical linkages in order to eliminate likely points of failure. The use of non-contact sensors may assist with this.
For example, the end sensor may be an optical sensor. Optical sensing solutions are known for the detection of edges based on the transmission of light and subsequent detection of reflected light ¨ and are relatively robust in the presence of the shocks and vibration generated during operation of a head. However, it should be appreciated that this is not intended to be limiting, and that other sensing technologies may be implemented with embodiments of the present invention, for example contact or ultrasonic sensors.
Reference to a sensing region should be understood to mean the area within which the end of a stem will be detected.

5 For example, the sensing region of an optical sensor will be delimited by the transmission angle of light emitted, and its detection capabilities.
Such regions may have edges or boundaries, the location of which may be described with reference to the apparatus or characteristics thereof. For example, an inner edge of a sensing region may be considered to be that closest to the feed axis.
The end sensors may be positioned such that inner edges of the sensing regions are offset from the feed axis. It may be possible for a portion of the stems to cross over the feed axis into the other side during processing. As such, it is desirable to reduce the likelihood of the end of a stem primarily positioned on one side falsely triggering the end sensor on the other side.
In an embodiment, at least one of the sensing regions may be offset from the feed axis by less than half of the minimum width of a stem to be processed by the timber-working device. For example, where the smallest diameter stem is 75 millimetres, one of the sensors may be positioned such that the inner edge of the sensing region is offset by less than 37.5 millimetres from the feed axis. In doing so, where a single stem is processed by the head, at least one of the sensors may be used to find the end of that stem.
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 a general purpose processor such as a microprocessor, or any other suitable means known in the art designed to perform the functions described.
The steps of a method 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:

6 FIG. 1 is a side view of an exemplary timber-working system including, for example, a forestry head according to one aspect of the present invention;
FIG. 2 is an elevated view of the forestry head;
FIG. 3 is a diagrammatic view of an exemplary control system for the timber-working system;
FIG. 4 is an end view of the forestry head in use, and FIG. 5 is a flowchart illustrating an exemplary method for operating the forestry head according to one aspect of the present invention.
DETAILED DESCRIPTION
FIG. 1 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 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. 2, the head 16 includes a frame 24 to which the tilt bracket 22 of FIG. us 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 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.
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.
RH and LH optical sensors 42a and 42b are attached to the frame 24 on either side of the feed axis 34. The operation of the sensors 42a and 42b will be discussed further below.

7 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 100 as shown by FIG. 3.
The control system 100 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 100 includes a first controller 102 on board the carrier 10 and a second controller 104 on board the head 16. The controllers 102, 104 are connected to one another via a communications bus 110 (e.g., a CAN bus).
io A human operator operates an operator input device 108, 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 110 ¨ for example a monitor. Certain automated functions may be controlled by first controller 102 and/or second controller 104.
The RH and LH optical sensors 42a and 42b are electronically coupled to the second controller 104, and configured to output respective signals indicative of the end of a stem being present within the respective sensing regions associated with the sensors 42a and 42b.
A measuring wheel encoder 112 is electrically coupled to the second controller 104, and configured to output a measuring signal indicating the length of the stem(s) that has passed the measuring wheel 36.
The head 16 has a number of valves 114 arranged, for example, in a valve block and coupled electrically to the second controller 104 so as to be under its control. The valves 114 include, for example, drive valves configured to control operation of the motors associated with the RH
and LH feed wheels 30a and 30b and RH and LH frame-mounted feed wheels 32a and 32b.
The valves 114 further include drive valves for controlling operation of the saws 38 and 40.
The control system 100 is configured to implement method 200 of FIG. 5, which will be described with reference to FIGS. 1 through 3, together with FIG. 4 showing the head 16 in use.
In step 202, a human operator operates the operator input device 108 to grasp a first stem 300 and a second stem 302 with the delimb arms 26a and 26b, and feed arms 28a and 28b such that the stems are positioned between the arm-mounted feed wheels 30a and 30b, and frame-mounted feed wheels 32a and 32b. The first stem 300 is positioned to the RH
side of the feed axis 34 (see FIG. 2, not illustrated in FIG. 4), while the second stem 302 is positioned to the LH
side of the feed axis 34.
In step 204, the first controller 102 receives from operator input device 108 a signal indicative of

8 a request to find the ends of the stems 300 and 302. In response to that signal, the first controller 102 broadcasts a request to find the ends of the stems 300 and 302 on bus 106.
In step 206, the second controller 104 receives the request to find the ends of the stems 300 and 302, and outputs control signals to the valves 114 responsible for control of the arm-.. mounted feed wheels 30a and 30b, and frame-mounted feed wheels 32a and 32b to feed the stems 300 and 302 along the feed axis 34.
In step 208, as the stems 300 and 302 are fed along feed axis 34 the RH and LH
optical sensors 42a and 42b output signals indicative of the presence of ends of the first stem 300 and second stem 302 being within a RH sensing region 304a and LH sensing region 304b respectively. It may be seen that the RH and LH sensing regions 304a and 304b do not intersect each other, nor the path of the stem on the other side of the feed axis 34. This prevents a false finding of an end being located due to triggering by the end of the other stem.
In step 208 the second controller 104 determines whether the ends of the first stem 300 and/or second stem 302 has been located, and outputs a control signal to valves 114 to control .. operation of the feed mechanism.
Control of the feed mechanism will depend on the conditions detected. For example, where only the end of stem 300 has been located, feed arm-mounted feed wheel 30a and frame-mounted feed wheel 32a may be stopped, while arm-mounted feed wheel 30b and frame-mounted feed wheel 32b continue to feed stem 302 through until its end is located.
Once both ends have been located, processing of the stems 300 and 302 may be performed as known in the art. For example, the stems 300 and 302 may be driven forward by a predetermined distance from their respective ends, and the saw operated to sever the stems and produce two logs at the desired length.
Referring to FIG. 4, it may be seen that where a single stem 306 (shown in dashed line) is to be processed by the head 16, either (or both) of the sensing regions 304a or 304b of sensors 42a and 42b respectively may be used to detect the presence of the end of the stem 306.
It is envisaged that the operator may input a selection of a single stem or double stem mode of operation into the control system 100 based on their observation of the number of stems being picked up by the head. The appropriate control routine may then be selected by the first controller 102 for implementation.
Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.

9

Claims

CLAIMS:

1. A timber-working device, including:
a frame, including a feed axis;
a drive systern configured to position a first stem on a first side of the feed axis, and a second stem on a second side of the feed axis;
a first end sensor having a first sensing region extending into the first side of the feed axis, and configured to output a signal indicative of the presence of an end of the first stem within the first sensing region; and a second end sensor having a second sensing region extending into the second side of the feed axis, and configured to output a signal indicative of the presence of an end of the second stem within the second sensing region.

2. The timber-working device of claim 1, wherein the drive system is configured to independently feed the first stem and second stem along the feed axis.

3. The timber-working device of claim 1 or claim 2, wherein the drive system includes a first drive mechanism located on the first side of the feed axis, and a second drive rnechanism located on the second side of the feed axis.

4. The timber-working device of claim 3, wherein the first drive mechanism includes a first pivoting drive arm and a first frame mounted feed wheel, and the second drive mechanism includes a second pivoting drive arm and a second frame mounted feed wheel.

5. The timber-working device of any one of claims 1 to 4, wherein the end sensors are positioned such that inner edges of the sensing regions are offset from the feed axis.

6. The timber-working device of claim 5, wherein the inner edge of at least one of the sensing regions is offset from the feed axis by less than half of a minimum width of a stern to be processed by the timber-working device.

7. The timber-working device of any one of claims 1 to 6, wherein at least one of the end sensors is a non-contact sensor.
Date Recue/Date Received 2021-06-04

8. The timber-working device of claim 7, wherein the at least one end sensor is an optical sensor.

9. The timber-working device of any one of claims 1 to 8, including a cutting device.

10. The timber-working device of any one of claims 1 to 9, including at least one controller configured to:
control the drive systern to feed the first stem and the second stem along the feed axis;
receive the signal from the first end sensor indicative of the end of the first stem being present within the first sensing region;
control the drive system to align the end of the first stem with a predetermined point along the feed axis;
receive the signal from the second end sensor indicative of the end of the second stern being present within the second sensing region; and control the second drive arm to align the end of the second stem with the predetermined point along the feed axis.

11 A method for aligning a first stem and a second stem being processed by a timber-working device, the method including the steps of:
positioning the first stem on a first side of a feed axis of a frame of the timber-working device, and the second stem on a second side of the feed axis;
controlling, using at least one controller, a drive system of the timber-working device to feed the first stem and the second stern along the feed axis;
receiving a signal from a first end sensor having a first sensing region extending into the first side of the feed axis, the signal being indicative of the end of the first stem being present within the first sensing region;
controlling, using at least one controller, the drive system to align the first stem with a predetermined point along the feed axis;
receiving a signal from a second end sensor having a second sensing region extending into the second side of the feed axis, the signal being indicative of the end of the second stem being present within the second sensing region; and controlling, using at least one controller, the drive system align the second stem with the predetermined point along the feed axis.

Date Recue/Date Received 2021-06-04

12. The method of claim 11, wherein the predetermined point along the feed axis is a cutting position at which the stems are to be severed by a cutting device.

13. The method of claim 12, including the step of cutting the stems with the cutting device once they are aligned.

14. An article of rnanufacture having cornputer storage medium storing computer readable program code executable by a computer to implement a method for aligning a first stem and a second stem being processed by a timber-working device, the code including:
cornputer readable program code positioning the first stem on a first side of a feed axis of a frame of the timber-working device, and the second stem on a second side of the feed axis;
cornputer readable prograrn code controlling a drive system of the timber-working device to feed the first stem and the second stem along the feed axis;
cornputer readable program code receiving a signal from a first end sensor having a first sensing region extending into the first side of the feed axis, the signal being indicative of the end of the first stern being present within the first sensing region;
cornputer readable prograrn code controlling a drive system of the timber-working device to align the first stem with a predetermined point along the feed axis;
computer readable program code receiving a signal from a second end sensor having a second sensing region extending into the second side of the feed axis, the signal being indicative of the end of the second stem being present within the second sensing region; and cornputer readable program code controlling a drive system of the timber-working device to align the second stem with the predetermined point along the feed axis.

Date Recue/Date Received 2021-06-04