CA2923446A1 - Saw apparatus with chain stretch detection - Google Patents
Saw apparatus with chain stretch detection Download PDFInfo
- Publication number
- CA2923446A1 CA2923446A1 CA2923446A CA2923446A CA2923446A1 CA 2923446 A1 CA2923446 A1 CA 2923446A1 CA 2923446 A CA2923446 A CA 2923446A CA 2923446 A CA2923446 A CA 2923446A CA 2923446 A1 CA2923446 A1 CA 2923446A1
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- Prior art keywords
- chain
- stretch
- saw apparatus
- groove
- swing
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
- A01G23/00—Forestry
- A01G23/02—Transplanting, uprooting, felling or delimbing trees
- A01G23/08—Felling trees
- A01G23/091—Sawing apparatus specially adapted for felling trees
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
- B23D59/00—Accessories specially designed for sawing machines or sawing devices
- B23D59/001—Measuring or control devices, e.g. for automatic control of work feed pressure on band saw blade
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27B—SAWS FOR WOOD OR SIMILAR MATERIAL; COMPONENTS OR ACCESSORIES THEREFOR
- B27B17/00—Chain saws; Equipment therefor
- B27B17/14—Arrangements for stretching the chain saw
Abstract
A saw apparatus (10) is provided, in which a chain support (36) attached movably to a mount (62) for movement relative thereto. An endless cutting chain (34) is trained about the chain support (36) and a chain driver (38), with a chain tensioner (90) urging the chain support (36) to move relative to the mount (62) to tension the chain (34), and a sensor (102) positioned to sense a position of the chain support (36) relative to the mount (62).
Description
SAW APPARATUS WITH CHAIN STRETCH DETECTION
Field of the Disclosure [001] The present disclosure relates to a saw apparatus including an endless cutting chain.
Background of the Disclosure
Field of the Disclosure [001] The present disclosure relates to a saw apparatus including an endless cutting chain.
Background of the Disclosure
[002] There are forestry machines that have a forestry head to fell a tree and to buck the tree into one or more logs. The head has a saw to perform such sawing operations.
[003] The endless cutting chain of the saw has broken during sawing causing a portion of the chain to fly away from the saw area. The chain failures result from chain link stretching and direct damage to the chain. Stretching fatigues the metal enabling fragment separation from the chain.
[004] It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
[005] Throughout this specification, the word "comprise", or variations thereof such as "comprises" or "comprising", 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.
Summary of the Disclosure
Summary of the Disclosure
[006] According to an aspect of the present disclosure, a saw apparatus comprises a mount, a chain support attached movably to the mount for movement relative thereto, a chain driver, an endless cutting chain trained about the chain support and the chain driver, a chain tensioner urging the chain support to move relative to the mount to tension the chain, and a sensor positioned to sense a position of the chain support relative to the mount.
[007] According to another aspect of the present disclosure, the saw apparatus comprises an electronic control system. The sensor is configured to generate a position signal indicative of the position of the chain support relative to the mount.
The control system is configured to receive the position signal, and determine if the cutting chain has stretched to a stretch threshold that is dependent on the position of the chain support relative to the mount. The control system may be configured to activate an alert if the cutting chain has stretched to the stretch threshold.
The saw apparatus may thus be configured to determine chain stretch during usage of the saw apparatus to determine if there is an increased risk of chain breakage.
The control system is configured to receive the position signal, and determine if the cutting chain has stretched to a stretch threshold that is dependent on the position of the chain support relative to the mount. The control system may be configured to activate an alert if the cutting chain has stretched to the stretch threshold.
The saw apparatus may thus be configured to determine chain stretch during usage of the saw apparatus to determine if there is an increased risk of chain breakage.
[008] The above and other features will become apparent from the following description and the attached drawings.
Brief Description of the Drawings
Brief Description of the Drawings
[009] The detailed description of the drawings refers to the accompanying figures in which:
[010] FIG. 1 is a diagrammatic view showing a saw apparatus including, for example, a forestry head;
[011] FIG. 2 is an elevational view showing the forestry head;
[012] FIG. 3 is a perspective view, with portions broken away, showing a chain saw of the forestry head;
[013] FIG. 4 is a perspective view, with portions of the saw broken away;
[014] FIG. 5 is an exploded perspective view showing a chain support of the saw;
[015] FIG. 6 is an exploded perspective view showing the chain support exploded from a swing of the saw;
[016] FIG. 7 is a perspective view showing the chain support assembled to the swing and a sensor positioned to sense a position of the chain support;
[017] FIG. 8 is a sectional view taken along lines 8-8 of FIG. 7 showing a first groove of an arm of the swing;
[018] FIG. 9 is a sectional view taken along lines 9-9 of FIG. 7 showing a second groove of the swing arm, and a sensor target embedded within a bar holder;
[019] FIG. 10 is a diagrammatic view showing a control system of the saw apparatus; and
[020] FIG. 11 is a flow chart showing a control scheme of the saw apparatus.
Detailed Description of the Drawings
Detailed Description of the Drawings
[021] Referring to FIG. 1, a saw apparatus 10 may be configured as a forestry machine that includes, for example, a self-propelled base machine 12, a forestry head 14, a boom assembly 16 attached pivotally to the base machine 12, and a coupler 17 interconnecting the boom assembly 16 and the head 14. The base machine 12 may be a track-type machine (FIG. 1) or a wheeled machine, either of which may have an operator's station at which a human operator may control the apparatus 10 and its head 14.
[022] Referring to FIG. 2, the forestry head 14 may be any type of forestry head with a saw. In FIG. 2, the forestry head 14 is configured, for example, as a harvester head. In such a case, the coupler 17 may be configured in any suitable manner so as to suspend the head 14 from an end of the boom assembly 16. For example, the coupler 17 may be configured for pivoting of the head 14 between a generally upright, felling position and a generally prone, processing position, and may include a frame 18 attached pivotally to the coupler 17 and a chain saw 20 attached to the frame 18 and configured to fell a tree in the harvesting position of the head 14 and to buck the tree into one or more logs in the processing position of the head 14 (the chain of chain saw 20 not shown in FIG. 2 for simplification of illustration).
[023] The head 14 may include a number of other features, such as, for example, a number of feed wheels 22, a number of delimb arms 24, a front delimb knife 26, a length-measurement wheel 28, and a topping saw 30. Two of the feed wheels 22 are attached respectively to two feed arms 32 attached pivotally to the frame 18, and a number of feed wheels 22 (e.g., one) may be attached to the frame 18 such that its axis of rotation is fixed relative to the frame 18. Each of the delimb arms 24 and the delimb knife 26 has a blade for delimbing the tree when the tree is fed past the arms
24 and knife 26 by the feed wheels 22 during processing. The topping saw 30 may be used to cut off a small-diameter top portion of the tree to maximize the value recovery of the tree (the chain of topping saw 30 not shown for simplification of illustration).
[024] Referring to FIGS. 3 and 4, the saw 20 is mounted to a saw housing 32 of the frame 18. The saw 20 includes an endless cutting chain 34, a chain support 36, a chain driver 38, and an attachment device 40 attaching the chain 34, the chain support 36, and the chain driver 38 to the saw housing 32.
[024] Referring to FIGS. 3 and 4, the saw 20 is mounted to a saw housing 32 of the frame 18. The saw 20 includes an endless cutting chain 34, a chain support 36, a chain driver 38, and an attachment device 40 attaching the chain 34, the chain support 36, and the chain driver 38 to the saw housing 32.
[025] The attachment device 40 includes a saw support ring 42 fastened to the saw housing 32 with threaded fasteners, a driver support ring 44 fastened to the saw support ring 42 with threaded fasteners, a bearing support ring 46 fastened to the driver support ring 44 with threaded fasteners, a bearing 48, and a swing 50.
The swing 50 includes an arm 52 and an arm support ring 54 to which the arm 52 is fastened with threaded fasteners. The bearing 48 is positioned between the bearing support ring 46 and the arm support ring 54 for rotation of the swing 50, the chain support 36 attached to the swing 50, and the chain 34 attached to the chain support 36 about an axis of rotation 56 of the chain driver 38.
The swing 50 includes an arm 52 and an arm support ring 54 to which the arm 52 is fastened with threaded fasteners. The bearing 48 is positioned between the bearing support ring 46 and the arm support ring 54 for rotation of the swing 50, the chain support 36 attached to the swing 50, and the chain 34 attached to the chain support 36 about an axis of rotation 56 of the chain driver 38.
[026] The chain support 36 includes a guide bar 58 and a bar holder 60 holding the guide bar 58. The chain 34 is trained about the guide bar 58 and the chain driver 38. The bar holder 60 is attached movably to a mount 62 of the saw apparatus for movement of the bar holder 60 and the guide bar 58 relative to the mount 62.
[027] The mount 62 may be any suitable mount to which the bar holder 60 may be attached movably. In the illustrated example, the mount 62 includes the base machine 12, the boom assembly 16, the coupler 17, the frame 18, and the attachment device 40. In such a case, the bar holder 60 is attached movably to the swing 50 for movement of the bar holder 60 and the guide bar 58 relative to the swing 50. Exemplarily, the bar holder 60 is attached movably to the arm 52 for movement of the bar holder 60 and the guide bar 58 relative to the arm 52.
[028] The chain driver 38 includes a hydraulic motor 64 and a sprocket 66. The sprocket 66 is attached to an output shaft of the motor 64 for rotation about the rotation axis 56. The chain 34 is trained about the sprocket 66.
[029] A hydraulic swing cylinder 68 is attached to the arm 52 and the frame 18 therebetween. The cylinder 68 is operable to pivot the swing 50, the chain support 36, and the chain 34 about the rotation axis 56 between a stowage position retracted into the saw housing 32 and a deployed position during a sawing event (e.g., felling, bucking).
[030] Referring to FIGS. 5 and 6, the bar holder 60 includes a first plate 70, a second plate 72, and a connector 73 connecting the first and second plates 70, therebetween. The connector 73 includes a T-shaped body 74 and a support body 76. The T-shaped body 74 and the support body 76 are positioned between the first and second plates 70, 72. The base of the T-shaped body 74 is positioned against the first plate 70, and the support body 76 is positioned against the second plate 72.
The cross member of the T-shaped body 74 merges into the support body 76 such that the T-shaped portion and the support body 76 cooperate to form an L-shaped body 77. Exemplarily, the plates 70, 72, T-shaped body 74, and support body 76 cooperate to form a monolithic body cut out of a block of material.
(0313 An end portion of the guide bar 58 has two tongues 78 with a slot 80 open at one end defined between the tongues 78. The guide bar 58 is fitted to the bar holder 60 such that the base of the T-shaped body 74 is positioned in the slot 80 with the tongues 78 positioned on either side of the base of the T-shaped body 74 and between the L-shaped body 77 and the first plate 70, in particular, between the first plate 70 and the cross member of the T-shaped body 74 and the support body 76.
Two threaded fasteners 82 fasten respectively the tongues 78 to the first plate 70, thereby attaching the guide bar 58 to the bar holder 60. Each fastener 82 includes a threaded portion that is proximal to the head of the fastener 82 and threaded to the first plate 70 and an unthreaded portion that is distal from the head, smaller in outside diameter than the threaded portion, and positioned in a respective unthreaded hole of the tongue 78.
[032] Referring to FIGS. 7 and 8, the bar holder 60 is fitted to the swing arm 52.
The swing arm 52 has a slot 84 open at a first end thereof. The connector 73, for example its L-shaped body 77, is positioned in the slot 84. The arm 52 includes a first branch 86 and a second branch 88. The slot 84 is defined between the branches 86, 88. When the connector 73, for example its L-shaped body 77, is positioned in the slot 84, the first plate 70 and the tongues 78 are positioned to a first side of the swing arm 52, and the second plate 72 is positioned to a second side of the swing arm 52 opposite to the first side. The first plate 70 overlaps the first and second branches 86, 88 such that the two tongues 78 are positioned respectively between the first and second branches 86, 88. The second plate 72 overlaps the first and second branches 86, 88.
[033] Referring to FIG. 4, the saw 20 includes a chain tensioner 90 urging the bar holder 60 and the guide bar 58 to move relative to the mount 62 to tension the chain 34. The chain tensioner 90 is attached to the swing 50 and its arm 52 and includes, for example, a piston and a spring urging the piston to extend through an opening in an end wall of the slot 84. During operation, the piston is under hydraulic pressure that urges the piston to extend through that opening. During replacement of the chain 34, the hydraulic pressure is relieved, allowing manual retraction of the piston against the spring to facilitate chain removal and subsequent installation of the new chain. Manual pressure on the piston is released so that the spring pre-tensions the chain. Hydraulic pressure is then re-introduced to raise the chain tension to an operational level.
[034] The chain tension 90 contacts the bar holder 60. The piston of the chain tensioner 90 contacts the T-shaped body 74 of the bar holder 60 so as to urge the bar holder 60 and the guide bar 58 away from the swing 50 and its arm 52, thereby tensioning the chain 34.
[035] Referring to FIG. 8, the bar holder 60 is positioned for slidable, linear movement in the slot 84 relative to the swing 50 and its arm 52 and thus relative to the mount 62 in response to pressure from the chain tensioner 90. The swing 50 is configured to guide the bar holder 60 and thus the guide bar 58 so as to move linearly. The connector 73, for example its L-shaped body 77, is positioned laterally between the branches 86, 88 for slidable movement against the branches 86, 88.
The branches 86, 88 are positioned transversely between the first and second plates 70, 72 and between the second plate 72 and the tongues 78.
[036] Referring to FIGS. 8 and 9, the arm 52 of the swing 50 includes a linear first groove 92 in the first branch 86 and a linear second groove 94 in the second branch 88. The second plate 72 overlaps the first and second grooves 92, 94. The bar holder 60 includes a first post 96 and a second post 98. Each post 96, 98 includes, for example, a threaded portion that is proximal to the head of the post 96, 98 and threaded to the second plate 72 and an unthreaded portion that is distal from the head and smaller in outside diameter than the threaded portion.
[037] The first post 96 extends through the second plate 72 into the first groove 92 for linear, slidable movement in and against the first groove 92, as shown, for example, in FIG. 8. The threaded portion of the first post 96 is threaded to the second plate 72, and the unthreaded portion is positioned in the first groove 92. The first post 96 can contact the opposite, closed ends of the first groove 92 to limit travel of the bar holder 60 and the guide bar 58 relative to the swing 50 and its arm 52.
[038] Referring to FIG. 9, the second post 98 extends through the second plate into the second groove 94 for linear, slidable movement in and against the second groove 94. The threaded portion of the second post 98 is threaded to the second plate 72, and the unthreaded portion is positioned in the second groove 94.
[039] The bar holder 60 comprises a sensor target 100. The sensor target 100 is embedded within the bar holder 60. For example, the sensor target 100 is embedded within the second plate 72 of the bar holder 60. The second plate 72 includes a hole 109, and the sensor target 100 is positioned and secured within the hole 109 (e.g., press fit into the hole 109). If the hole 109 is a through-hole, filler material (not shown), e.g., epoxy, may fill the hole 109 above the sensor target 100, inhibiting ingress of debris into the hole 109. The sensor target 100 is thus in register with the second groove 94 for linear movement along the second groove with the bar holder 60. The sensor target 100 is configured, for example, as a permanent magnet.
[040] Alternatively, the sensor target 100 may be attached to a tip of the second post 98 so as to be mounted thereto. In such a case, the sensor target 100 is positioned in the second groove 94 for linear movement therein as the bar holder 60 moves linearly.
[041] Referring to FIGS. 7 and 9, the saw 20 has a sensor 102 positioned to sense a position of the chain support 36 relative to the mount 62. The sensor 102 is positioned to sense a position of the bar holder 60 relative to the swing 50 and thus the mount 62 by use of the sensor target 100 of the bar holder 60. The sensor is configured to generate a position signal indicative of the position of the sensor target 100 of the bar holder 60 of the chain support 36 relative to the swing 50 of the mount 62.
[042] The sensor 102 is configured, for example, as a magnetostrictive linear position sensor configured to sense linear position. In such a case, the sensor 102 has an electronics unit 104 and a magnetostrictive sensing element 106 in the form of a longitudinal waveguide. The electronics unit 104 is positioned in a cavity 108 of the arm 52. The cavity 108 is filled with a filler material (not shown), e.g., epoxy, sufficient to secure the unit 104 in the cavity 108. The sensing element 106 is positioned in the second groove 94 so as to extend longitudinally therein and is used to determine the position of the sensor target 100 along the length of the sensing element 106. A dead band 107 is positioned at either end of the sensing element 106. The second groove 94 is filled with a filler material (not shown), e.g., epoxy, sufficient to secure the sensing element 106 in the second groove 94. The filler material may only partially fill the second groove 94, allowing space for the post 98 to extend into and move linearly in the second groove 94. In an example, the sensor 102 is model C-S-0072-V-P1 available from MTS Systems Corporation, Sensors Division, in Cary, North Carolina.
[043] In another example, the sensor target 100 may comprise a series of magnets mounted to the plate 72 of the bar holder 60 (e.g., via a magnet carrier) and arranged linearly relative to one another along the linear path of movement of the bar holder 60. In the case where the sensor 102 is a magnetostrictive linear position sensor, the sensor 102 may be configured to sense the position of those magnets with the sensing element 106 (e.g., in the form of a longitudinal waveguide) and resolve those measurements into a single voltage output from the electronics unit 104 indicative of the position of chain support 36, and its bar holder 60, relative to the mount 62. Use of the series of linearly arranged magnets promotes accuracy and error reduction in the position determination. The electronics unit 104 may be smaller than depicted in the drawings, and the sensing element 106 may be without a deadband at each of its opposite ends. The sensor target 100 and the sensor may be mounted respectively to the bar holder 60 and the arm 52 in any suitable manner.
[044] Referring to FIG. 10, the saw apparatus 10 includes an electronic control system 110. The control system 110 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 110 includes a first controller 112 on board the head 14 and a second controller 114 on board the base machine 12. The controllers 112, 114 are connected to one another via a communications bus 116 (e.g., a CAN bus). The sensor 102 is coupled electrically to the first controller 112. The head 14 has a number of valves 118 arranged, for example, in a valve block and coupled electrically to the first controller 112 so as to be under its control. The valves 118 include, for example, a motor valve configured to control operation of the motor 64 and a swing valve configured to control pivotal movement of the swing 50.
[045] Referring to FIG. 11, the control system 110 is configured to perform a control scheme 210. As part of the control scheme 210, the control system 110 is configured to receive the position signal and determine if the cutting chain 34 has stretched to a stretch threshold dependent on the position of the sensor target 100 of the bar holder 60 of the chain support 36 relative to the swing 50 of the mount 62 in order to determine if a risk of chain breakage has increased. In an example, the control system 110 may be configured to monitor a stretch trend of the chain 34 and determine if the stretch trend reaches the stretch threshold. In so doing, the control system 110 may be configured to determine a predicted stretch indication and an actual stretch indication and to determine if the actual stretch indication exceeds the predicted stretch indication by at least the stretch threshold. The control system 110 may activate an alert if the actual stretch indication does exceed the predicted stretch indication by at least the stretch threshold. An example of the control scheme 210 is shown in FIG. 12.
[046] In step 212 of the control scheme 210, a human operator operates an operator input device 122 located at the operator's station of the base machine 12 in response to which the second controller 114 receives from the operator input device 122 an operate-saw request signal indicative of a request from the human operator to operate the saw 20. In response to the operate-saw request signal, the second controller 114 broadcasts an operate-saw request message on the bus 116. The first controller 112 receives that message and, in response thereto, outputs control signals to the two valves 118 responsible respectively for controlling the motor 64 and the swing cylinder 68 and takes an initial position reading, Po, of the position of the sensor target 100 from the sensor 102. The first controller 112 stores this initial position reading in its memory so as to begin a historical watch of the behavior of the chain 34. Before the control scheme 210 advances to step 214, the first controller 114 may set a counter variable, n, equal to 1 and a variable Ssum equal to 0.
[047] Step 214 relates to the next time that a human operator operates the operator input device 122. In step 214, the second controller 114 receives from the operator input device 122 the operate-saw request signal indicative of another request from the human operator to operate the saw 20. In response to that operate-saw request signal, the second controller 114 broadcasts an operate-saw request message on the bus 116. The first controller 112 receives that message and, in response thereto, outputs control signals to the two valves 118 responsible respectively for controlling the motor 64 and the swing cylinder 68 and takes a position reading, Pn, of the position of the sensor target 100 from the sensor 102. Pn would be P1 if it is the position reading immediately after Po, or P2 if it is the position reading immediately after P1, and so on. As such, Po and P1 are consecutive position readings, and Pn and Pn+i are consecutive positions readings. The control scheme 210 advances to step 216.
[048] In step 216, the first controller 112 determines an actual stretch indication, Sn, indicative of an actual stretch in the length of the chain 34 between Pn and Po-i.
In an example, the first controller 112 determines the actual stretch indication according to the following equation:
= Pt ¨
3_, ________________________________________ (100) 1-71-1 .
In such a case, the actual stretch indication is an actual stretch percentage.
[049] In step 218, the first controller 112 determines if n is greater than or equal to 2. If yes, the control scheme 210 advances to step 220. If no, the control scheme 210 advances to step 228 in which the first controller 112 adds one to the counter n and then advances back to step 214. Alternatively, in step 218, the first controller 112 may determine if n is equal to 1, and, if yes, the control scheme 210 advances to step 228, and, if no, the control scheme 210 advances to step 220.
[050] The control scheme 210 advances to step 220 if the counter is two or more, meaning that at least three position readings have been taken from the sensor 102.
In step 220, the first controller 112 determines the sum, Ssum, of all prior actual stretch indications, i.e., S1 to Sn..1. The sum does not include the current actual stretch indication, Sn. The first controller 112 may determine the sum according to the following equation: Ssum = Ssum Sn-i. The control scheme 210 advances to step 222.
[051] In step 222, the first controller 112 determines a predicted stretch indication, SpR. In an example, the predicted stretch indication is the average of all prior actual stretch indications, and is determined according to the following equation:
SpR = Ssum /(n-1). The control scheme 210 advances to step 224.
[052] In step 224, the first controller 112 determines if the chain 34 has stretched to a stretch threshold, STH. For example, the first controller 112 determines if the actual stretch indication exceeds the predicted stretch indication by at least the stretch threshold. The first controller 112 does so by determining if the difference between the current actual stretch indication and the predicted stretch indication is greater than or equal to the stretch threshold according to the following equation:
Sn ¨ SpR STH. If no, the control scheme 210 advances to step 228. If yes, the control scheme 210 advances to step 226. To determine the stretch threshold, chain manufacturers may be contacted for an indication of acceptable chain stretch.
The stretch threshold may be about 1.0% to about 1.5%.
[053] In step 226, the control system 110 activates an alert if the cutting chain 34 has stretched to the stretch threshold. The first controller 112 broadcasts an alert message on the bus 116, and the second controller 114 receives the alert message.
The second controller 114 outputs a control signal causing an output device 124 to issue the alert. The alert may be in any suitable form, such as, for example, a visual indication, an audible indication, a tactile indication, or any combination thereof, to name but a few possibilities. In an example, the output device 124 is a monitor, and the alert is a visual alert on the screen of the monitor (e.g., a pop-up).
Illustratively, the output device 124 is coupled electrically to the second controller 114. In other examples, the output device 124 may be coupled electrically directly to the bus 116.
[054] The alert may remain active until the human operator acknowledges the alert. For example, in the case where the output device 124 is a monitor and the alert is a visual alert on a screen of the monitor, the visual alert may remain active until the operator presses a button (e.g., escape button on a keyboard coupled electrically to the second controller 114 configured as a PC) or other operator input device, acknowledging the alert.
[055] In step 228, the first controller 112 adds one to the counter n.
Afterwards, the control scheme 210 advances back to step 214.
[056] The first controller 112 may store in its memory a number of values. For example, for historical and evaluation purposes, it may store all of the position readings and/or all of the actual stretch percentages, so as to keep a historical log of those values ("and/or" means and-or-or). It may also store the stretch threshold as a constant, and may store all SSUM and/or SPR values so as to keep a historical log of those values or only store them until updated in the next loop of the control scheme 210.
[057] In the above example of the control scheme 210, the actual and predicted stretch indications are stretch percentages. In another example of the control scheme 210, the actual stretch indication is an actual change in position from one position reading to the next position reading, and the predicted stretch indication is a predicted change in position. Change in position may be represented by A, and the control scheme 210 may be modified as follows:
step 216 is replaced by An= Pn ¨ Pn-1, step 220 is replaced by Asum.Asum step 222 is replaced by APR = sum/(n-1) step 224 is replaced by An ¨ APR =?- ATH.
[058] In such an example of the control scheme 210, the first controller 112 may store in its memory all of the position readings and/or all of the actual changes in position, so as to keep a historical log of those values. It may also store the stretch threshold as a constant, and may store all Asum and/or APR values so as to keep a historical log of those values or only store them until updated in the next loop of the control scheme 210.
[059] In yet another example, the control scheme 210 may be modified such that no predicted stretch indication is taken into account, and the actual stretch indication is the position reading from the sensor 102. In such a case, the first controller 112 compares each position reading to a stretch threshold in the form of a position threshold. Once the position reading reaches the position threshold, the first controller 112 signals the second controller 114 to activate the alert. In such an example of the control scheme 210, the first controller 112 may store in its memory all of the position readings, so as to keep a historical log of those values.
It may also store the position threshold as a constant.
[060] In another example of the saw apparatus 10, the saw apparatus may be configured as a hand-held saw apparatus. In that case, the mount may be the frame of the hand-held device to which the saw is attached, without a swing. The chain support may be attached movably to the frame for movement relative thereto.
The chain tensioner may urge the chain support to move relative to the frame to tension the chain. The sensor may be positioned (e.g., attached to the frame) to sense a position of the chain support relative to the frame. Since the saw apparatus is a hand-held device, the control system may have a single electronic controller.
[061] The welds, threads, and hydraulic and electrical lines of the forestry head have not been shown for simplification of illustration, it being understood that it would be well within the skill of one of ordinary skill in the art to provide those features without undue experimentation.
[062] While the disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description is to be considered as exemplary and not restrictive in character, it being understood that illustrative embodiment(s) have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected.
It will be noted that alternative embodiments of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations that incorporate one or more of the features of the present disclosure and fall within the spirit and scope of the appended claims.
The cross member of the T-shaped body 74 merges into the support body 76 such that the T-shaped portion and the support body 76 cooperate to form an L-shaped body 77. Exemplarily, the plates 70, 72, T-shaped body 74, and support body 76 cooperate to form a monolithic body cut out of a block of material.
(0313 An end portion of the guide bar 58 has two tongues 78 with a slot 80 open at one end defined between the tongues 78. The guide bar 58 is fitted to the bar holder 60 such that the base of the T-shaped body 74 is positioned in the slot 80 with the tongues 78 positioned on either side of the base of the T-shaped body 74 and between the L-shaped body 77 and the first plate 70, in particular, between the first plate 70 and the cross member of the T-shaped body 74 and the support body 76.
Two threaded fasteners 82 fasten respectively the tongues 78 to the first plate 70, thereby attaching the guide bar 58 to the bar holder 60. Each fastener 82 includes a threaded portion that is proximal to the head of the fastener 82 and threaded to the first plate 70 and an unthreaded portion that is distal from the head, smaller in outside diameter than the threaded portion, and positioned in a respective unthreaded hole of the tongue 78.
[032] Referring to FIGS. 7 and 8, the bar holder 60 is fitted to the swing arm 52.
The swing arm 52 has a slot 84 open at a first end thereof. The connector 73, for example its L-shaped body 77, is positioned in the slot 84. The arm 52 includes a first branch 86 and a second branch 88. The slot 84 is defined between the branches 86, 88. When the connector 73, for example its L-shaped body 77, is positioned in the slot 84, the first plate 70 and the tongues 78 are positioned to a first side of the swing arm 52, and the second plate 72 is positioned to a second side of the swing arm 52 opposite to the first side. The first plate 70 overlaps the first and second branches 86, 88 such that the two tongues 78 are positioned respectively between the first and second branches 86, 88. The second plate 72 overlaps the first and second branches 86, 88.
[033] Referring to FIG. 4, the saw 20 includes a chain tensioner 90 urging the bar holder 60 and the guide bar 58 to move relative to the mount 62 to tension the chain 34. The chain tensioner 90 is attached to the swing 50 and its arm 52 and includes, for example, a piston and a spring urging the piston to extend through an opening in an end wall of the slot 84. During operation, the piston is under hydraulic pressure that urges the piston to extend through that opening. During replacement of the chain 34, the hydraulic pressure is relieved, allowing manual retraction of the piston against the spring to facilitate chain removal and subsequent installation of the new chain. Manual pressure on the piston is released so that the spring pre-tensions the chain. Hydraulic pressure is then re-introduced to raise the chain tension to an operational level.
[034] The chain tension 90 contacts the bar holder 60. The piston of the chain tensioner 90 contacts the T-shaped body 74 of the bar holder 60 so as to urge the bar holder 60 and the guide bar 58 away from the swing 50 and its arm 52, thereby tensioning the chain 34.
[035] Referring to FIG. 8, the bar holder 60 is positioned for slidable, linear movement in the slot 84 relative to the swing 50 and its arm 52 and thus relative to the mount 62 in response to pressure from the chain tensioner 90. The swing 50 is configured to guide the bar holder 60 and thus the guide bar 58 so as to move linearly. The connector 73, for example its L-shaped body 77, is positioned laterally between the branches 86, 88 for slidable movement against the branches 86, 88.
The branches 86, 88 are positioned transversely between the first and second plates 70, 72 and between the second plate 72 and the tongues 78.
[036] Referring to FIGS. 8 and 9, the arm 52 of the swing 50 includes a linear first groove 92 in the first branch 86 and a linear second groove 94 in the second branch 88. The second plate 72 overlaps the first and second grooves 92, 94. The bar holder 60 includes a first post 96 and a second post 98. Each post 96, 98 includes, for example, a threaded portion that is proximal to the head of the post 96, 98 and threaded to the second plate 72 and an unthreaded portion that is distal from the head and smaller in outside diameter than the threaded portion.
[037] The first post 96 extends through the second plate 72 into the first groove 92 for linear, slidable movement in and against the first groove 92, as shown, for example, in FIG. 8. The threaded portion of the first post 96 is threaded to the second plate 72, and the unthreaded portion is positioned in the first groove 92. The first post 96 can contact the opposite, closed ends of the first groove 92 to limit travel of the bar holder 60 and the guide bar 58 relative to the swing 50 and its arm 52.
[038] Referring to FIG. 9, the second post 98 extends through the second plate into the second groove 94 for linear, slidable movement in and against the second groove 94. The threaded portion of the second post 98 is threaded to the second plate 72, and the unthreaded portion is positioned in the second groove 94.
[039] The bar holder 60 comprises a sensor target 100. The sensor target 100 is embedded within the bar holder 60. For example, the sensor target 100 is embedded within the second plate 72 of the bar holder 60. The second plate 72 includes a hole 109, and the sensor target 100 is positioned and secured within the hole 109 (e.g., press fit into the hole 109). If the hole 109 is a through-hole, filler material (not shown), e.g., epoxy, may fill the hole 109 above the sensor target 100, inhibiting ingress of debris into the hole 109. The sensor target 100 is thus in register with the second groove 94 for linear movement along the second groove with the bar holder 60. The sensor target 100 is configured, for example, as a permanent magnet.
[040] Alternatively, the sensor target 100 may be attached to a tip of the second post 98 so as to be mounted thereto. In such a case, the sensor target 100 is positioned in the second groove 94 for linear movement therein as the bar holder 60 moves linearly.
[041] Referring to FIGS. 7 and 9, the saw 20 has a sensor 102 positioned to sense a position of the chain support 36 relative to the mount 62. The sensor 102 is positioned to sense a position of the bar holder 60 relative to the swing 50 and thus the mount 62 by use of the sensor target 100 of the bar holder 60. The sensor is configured to generate a position signal indicative of the position of the sensor target 100 of the bar holder 60 of the chain support 36 relative to the swing 50 of the mount 62.
[042] The sensor 102 is configured, for example, as a magnetostrictive linear position sensor configured to sense linear position. In such a case, the sensor 102 has an electronics unit 104 and a magnetostrictive sensing element 106 in the form of a longitudinal waveguide. The electronics unit 104 is positioned in a cavity 108 of the arm 52. The cavity 108 is filled with a filler material (not shown), e.g., epoxy, sufficient to secure the unit 104 in the cavity 108. The sensing element 106 is positioned in the second groove 94 so as to extend longitudinally therein and is used to determine the position of the sensor target 100 along the length of the sensing element 106. A dead band 107 is positioned at either end of the sensing element 106. The second groove 94 is filled with a filler material (not shown), e.g., epoxy, sufficient to secure the sensing element 106 in the second groove 94. The filler material may only partially fill the second groove 94, allowing space for the post 98 to extend into and move linearly in the second groove 94. In an example, the sensor 102 is model C-S-0072-V-P1 available from MTS Systems Corporation, Sensors Division, in Cary, North Carolina.
[043] In another example, the sensor target 100 may comprise a series of magnets mounted to the plate 72 of the bar holder 60 (e.g., via a magnet carrier) and arranged linearly relative to one another along the linear path of movement of the bar holder 60. In the case where the sensor 102 is a magnetostrictive linear position sensor, the sensor 102 may be configured to sense the position of those magnets with the sensing element 106 (e.g., in the form of a longitudinal waveguide) and resolve those measurements into a single voltage output from the electronics unit 104 indicative of the position of chain support 36, and its bar holder 60, relative to the mount 62. Use of the series of linearly arranged magnets promotes accuracy and error reduction in the position determination. The electronics unit 104 may be smaller than depicted in the drawings, and the sensing element 106 may be without a deadband at each of its opposite ends. The sensor target 100 and the sensor may be mounted respectively to the bar holder 60 and the arm 52 in any suitable manner.
[044] Referring to FIG. 10, the saw apparatus 10 includes an electronic control system 110. The control system 110 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 110 includes a first controller 112 on board the head 14 and a second controller 114 on board the base machine 12. The controllers 112, 114 are connected to one another via a communications bus 116 (e.g., a CAN bus). The sensor 102 is coupled electrically to the first controller 112. The head 14 has a number of valves 118 arranged, for example, in a valve block and coupled electrically to the first controller 112 so as to be under its control. The valves 118 include, for example, a motor valve configured to control operation of the motor 64 and a swing valve configured to control pivotal movement of the swing 50.
[045] Referring to FIG. 11, the control system 110 is configured to perform a control scheme 210. As part of the control scheme 210, the control system 110 is configured to receive the position signal and determine if the cutting chain 34 has stretched to a stretch threshold dependent on the position of the sensor target 100 of the bar holder 60 of the chain support 36 relative to the swing 50 of the mount 62 in order to determine if a risk of chain breakage has increased. In an example, the control system 110 may be configured to monitor a stretch trend of the chain 34 and determine if the stretch trend reaches the stretch threshold. In so doing, the control system 110 may be configured to determine a predicted stretch indication and an actual stretch indication and to determine if the actual stretch indication exceeds the predicted stretch indication by at least the stretch threshold. The control system 110 may activate an alert if the actual stretch indication does exceed the predicted stretch indication by at least the stretch threshold. An example of the control scheme 210 is shown in FIG. 12.
[046] In step 212 of the control scheme 210, a human operator operates an operator input device 122 located at the operator's station of the base machine 12 in response to which the second controller 114 receives from the operator input device 122 an operate-saw request signal indicative of a request from the human operator to operate the saw 20. In response to the operate-saw request signal, the second controller 114 broadcasts an operate-saw request message on the bus 116. The first controller 112 receives that message and, in response thereto, outputs control signals to the two valves 118 responsible respectively for controlling the motor 64 and the swing cylinder 68 and takes an initial position reading, Po, of the position of the sensor target 100 from the sensor 102. The first controller 112 stores this initial position reading in its memory so as to begin a historical watch of the behavior of the chain 34. Before the control scheme 210 advances to step 214, the first controller 114 may set a counter variable, n, equal to 1 and a variable Ssum equal to 0.
[047] Step 214 relates to the next time that a human operator operates the operator input device 122. In step 214, the second controller 114 receives from the operator input device 122 the operate-saw request signal indicative of another request from the human operator to operate the saw 20. In response to that operate-saw request signal, the second controller 114 broadcasts an operate-saw request message on the bus 116. The first controller 112 receives that message and, in response thereto, outputs control signals to the two valves 118 responsible respectively for controlling the motor 64 and the swing cylinder 68 and takes a position reading, Pn, of the position of the sensor target 100 from the sensor 102. Pn would be P1 if it is the position reading immediately after Po, or P2 if it is the position reading immediately after P1, and so on. As such, Po and P1 are consecutive position readings, and Pn and Pn+i are consecutive positions readings. The control scheme 210 advances to step 216.
[048] In step 216, the first controller 112 determines an actual stretch indication, Sn, indicative of an actual stretch in the length of the chain 34 between Pn and Po-i.
In an example, the first controller 112 determines the actual stretch indication according to the following equation:
= Pt ¨
3_, ________________________________________ (100) 1-71-1 .
In such a case, the actual stretch indication is an actual stretch percentage.
[049] In step 218, the first controller 112 determines if n is greater than or equal to 2. If yes, the control scheme 210 advances to step 220. If no, the control scheme 210 advances to step 228 in which the first controller 112 adds one to the counter n and then advances back to step 214. Alternatively, in step 218, the first controller 112 may determine if n is equal to 1, and, if yes, the control scheme 210 advances to step 228, and, if no, the control scheme 210 advances to step 220.
[050] The control scheme 210 advances to step 220 if the counter is two or more, meaning that at least three position readings have been taken from the sensor 102.
In step 220, the first controller 112 determines the sum, Ssum, of all prior actual stretch indications, i.e., S1 to Sn..1. The sum does not include the current actual stretch indication, Sn. The first controller 112 may determine the sum according to the following equation: Ssum = Ssum Sn-i. The control scheme 210 advances to step 222.
[051] In step 222, the first controller 112 determines a predicted stretch indication, SpR. In an example, the predicted stretch indication is the average of all prior actual stretch indications, and is determined according to the following equation:
SpR = Ssum /(n-1). The control scheme 210 advances to step 224.
[052] In step 224, the first controller 112 determines if the chain 34 has stretched to a stretch threshold, STH. For example, the first controller 112 determines if the actual stretch indication exceeds the predicted stretch indication by at least the stretch threshold. The first controller 112 does so by determining if the difference between the current actual stretch indication and the predicted stretch indication is greater than or equal to the stretch threshold according to the following equation:
Sn ¨ SpR STH. If no, the control scheme 210 advances to step 228. If yes, the control scheme 210 advances to step 226. To determine the stretch threshold, chain manufacturers may be contacted for an indication of acceptable chain stretch.
The stretch threshold may be about 1.0% to about 1.5%.
[053] In step 226, the control system 110 activates an alert if the cutting chain 34 has stretched to the stretch threshold. The first controller 112 broadcasts an alert message on the bus 116, and the second controller 114 receives the alert message.
The second controller 114 outputs a control signal causing an output device 124 to issue the alert. The alert may be in any suitable form, such as, for example, a visual indication, an audible indication, a tactile indication, or any combination thereof, to name but a few possibilities. In an example, the output device 124 is a monitor, and the alert is a visual alert on the screen of the monitor (e.g., a pop-up).
Illustratively, the output device 124 is coupled electrically to the second controller 114. In other examples, the output device 124 may be coupled electrically directly to the bus 116.
[054] The alert may remain active until the human operator acknowledges the alert. For example, in the case where the output device 124 is a monitor and the alert is a visual alert on a screen of the monitor, the visual alert may remain active until the operator presses a button (e.g., escape button on a keyboard coupled electrically to the second controller 114 configured as a PC) or other operator input device, acknowledging the alert.
[055] In step 228, the first controller 112 adds one to the counter n.
Afterwards, the control scheme 210 advances back to step 214.
[056] The first controller 112 may store in its memory a number of values. For example, for historical and evaluation purposes, it may store all of the position readings and/or all of the actual stretch percentages, so as to keep a historical log of those values ("and/or" means and-or-or). It may also store the stretch threshold as a constant, and may store all SSUM and/or SPR values so as to keep a historical log of those values or only store them until updated in the next loop of the control scheme 210.
[057] In the above example of the control scheme 210, the actual and predicted stretch indications are stretch percentages. In another example of the control scheme 210, the actual stretch indication is an actual change in position from one position reading to the next position reading, and the predicted stretch indication is a predicted change in position. Change in position may be represented by A, and the control scheme 210 may be modified as follows:
step 216 is replaced by An= Pn ¨ Pn-1, step 220 is replaced by Asum.Asum step 222 is replaced by APR = sum/(n-1) step 224 is replaced by An ¨ APR =?- ATH.
[058] In such an example of the control scheme 210, the first controller 112 may store in its memory all of the position readings and/or all of the actual changes in position, so as to keep a historical log of those values. It may also store the stretch threshold as a constant, and may store all Asum and/or APR values so as to keep a historical log of those values or only store them until updated in the next loop of the control scheme 210.
[059] In yet another example, the control scheme 210 may be modified such that no predicted stretch indication is taken into account, and the actual stretch indication is the position reading from the sensor 102. In such a case, the first controller 112 compares each position reading to a stretch threshold in the form of a position threshold. Once the position reading reaches the position threshold, the first controller 112 signals the second controller 114 to activate the alert. In such an example of the control scheme 210, the first controller 112 may store in its memory all of the position readings, so as to keep a historical log of those values.
It may also store the position threshold as a constant.
[060] In another example of the saw apparatus 10, the saw apparatus may be configured as a hand-held saw apparatus. In that case, the mount may be the frame of the hand-held device to which the saw is attached, without a swing. The chain support may be attached movably to the frame for movement relative thereto.
The chain tensioner may urge the chain support to move relative to the frame to tension the chain. The sensor may be positioned (e.g., attached to the frame) to sense a position of the chain support relative to the frame. Since the saw apparatus is a hand-held device, the control system may have a single electronic controller.
[061] The welds, threads, and hydraulic and electrical lines of the forestry head have not been shown for simplification of illustration, it being understood that it would be well within the skill of one of ordinary skill in the art to provide those features without undue experimentation.
[062] While the disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description is to be considered as exemplary and not restrictive in character, it being understood that illustrative embodiment(s) have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected.
It will be noted that alternative embodiments of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations that incorporate one or more of the features of the present disclosure and fall within the spirit and scope of the appended claims.
Claims (21)
1. A saw apparatus, comprising:
a mount, a chain support attached movably to the mount for movement relative thereto, a chain driver, an endless cutting chain trained about the chain support and the chain driver, a chain tensioner urging the chain support to move relative to the mount to tension the chain, and a sensor positioned to sense a position of the chain support relative to the mount.
a mount, a chain support attached movably to the mount for movement relative thereto, a chain driver, an endless cutting chain trained about the chain support and the chain driver, a chain tensioner urging the chain support to move relative to the mount to tension the chain, and a sensor positioned to sense a position of the chain support relative to the mount.
2. The saw apparatus of claim 1, wherein the sensor is a position sensor.
3. The saw apparatus of claim 2, wherein the sensor is a linear position sensor.
4. The saw apparatus of claim 1, comprising an electronic control system, wherein the sensor is configured to generate a position signal indicative of the position of the chain support relative to the mount, and the control system is configured to receive the position signal, and determine if the cutting chain has stretched to a stretch threshold that is dependent on the position of the chain support relative to the mount.
5. The saw apparatus of claim 4, wherein the control system is configured to determine if the cutting chain has stretched to the stretch threshold at least partially by use of a first position reading of the position and a second position reading of the position consecutive to the first position reading.
6. The saw apparatus of claim 5, wherein the chain driver comprises a motor, and the control system is configured to receive the first and second position readings respectively in response to two consecutive requests to start the motor.
7. The saw apparatus of claim 4, wherein the control system is configured to determine a predicted stretch indication and an actual stretch indication and to determine if the actual stretch indication exceeds the predicted stretch indication by at least the stretch threshold.
8. The saw apparatus of claim 7, wherein the actual stretch indication is an actual stretch percentage, and the control system is configured to determine the actual stretch percentage dependent on a current position reading of the position and a position reading of the position immediately preceding the current position reading.
9. The saw apparatus of claim 8, wherein the predicted stretch indication is a predicted stretch percentage, the actual stretch percentage is a current actual stretch percentage, and the control system is configured to determine the predicted stretch percentage dependent on an average of actual stretch percentages prior to the current actual stretch percentage.
10. The saw apparatus of claim 7, wherein the predicted stretch indication is a predicted stretch percentage, and the control system is configured to determine the predicted stretch percentage dependent on an average of actual stretch percentages.
11. The saw apparatus of claim 4, wherein the control system is configured to monitor a stretch trend of the chain and determine if the stretch trend reaches the stretch threshold.
12. The saw apparatus of claim 4, wherein the control system is configured to activate an alert if the cutting chain has stretched to the stretch threshold.
13. The saw apparatus of any one of the preceding claims, wherein the mount comprises a housing and a swing attached pivotally to the housing, the chain support comprises a guide bar and a bar holder holding the guide bar and attached movably to the swing for movement of the bar holder and the guide bar relative to the swing, the chain tensioner is attached to the swing and urges the guide bar to move relative to the swing to tension the chain, and the sensor is attached to the swing to sense a position of the bar holder relative to the swing.
14. The saw apparatus of claim 13, wherein the swing comprises a linear groove, and the sensor extends in the groove.
15. The saw apparatus of claim 13, wherein the swing comprises a linear groove, and the bar holder comprises a post extending into the groove for linear movement therein and configured to contact an end of the groove to limit travel of the bar holder relative to the swing.
16. The saw apparatus of claim 13, wherein the swing comprises a linear first groove and a linear second groove, the bar holder comprises a post that extends into the first groove and is configured to contact an end of the first groove to limit travel of the bar holder relative to the swing, and the bar holder comprises a sensor target in register with the second groove for linear movement along the second groove with the bar holder.
17. The saw apparatus of claim 1, wherein the chain support comprises a guide bar and a bar holder holding the guide bar and attached movably to the mount for movement of the bar holder and the guide bar relative to the mount, the sensor is positioned to sense a position of the bar holder relative to the mount.
18. The saw apparatus of claim 17, wherein the bar holder is attached to the mount for linear movement relative thereto.
19. The saw apparatus of claim 17, wherein the mount comprises a groove, and the sensor is positioned at least partially in the groove.
20. The saw apparatus of claim 19, wherein the bar holder comprises a sensor target in register with the groove.
21. The saw apparatus of claim 20, wherein the mount comprises a swing comprising the groove, the sensor target comprises a magnet, and the sensor comprises a waveguide positioned in the groove.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NZ61544413A NZ615444A (en) | 2013-09-12 | 2013-09-12 | Saw apparatus with chain stretch detection |
| NZ615444 | 2013-09-12 | ||
| PCT/NZ2014/000197 WO2015038011A1 (en) | 2013-09-12 | 2014-09-11 | Saw apparatus with chain stretch detection |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2923446A1 true CA2923446A1 (en) | 2015-03-19 |
| CA2923446C CA2923446C (en) | 2021-06-08 |
Family
ID=51730562
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2923446A Active CA2923446C (en) | 2013-09-12 | 2014-09-11 | Saw apparatus with chain stretch detection |
Country Status (3)
| Country | Link |
|---|---|
| CA (1) | CA2923446C (en) |
| NZ (1) | NZ615444A (en) |
| WO (1) | WO2015038011A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11400530B2 (en) | 2017-06-09 | 2022-08-02 | Husqvarna Ab | Chainsaw and method |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI126648B (en) * | 2015-09-30 | 2017-03-31 | Ponsse Oyj | Chain saw and method of maneuvering the movements of a saw blade of it |
| FI126912B (en) | 2015-09-30 | 2017-07-31 | Ponsse Oyj | Arrangement for transferring fluid to a chain saw sword |
| FI20175449A (en) | 2016-09-21 | 2018-03-22 | Deere & Co | Saw machine with chain clip |
| JP6732313B2 (en) * | 2018-10-01 | 2020-07-29 | 株式会社片岡製作所 | Cell culture instrument and method of manufacturing cell culture instrument |
| JP7343119B2 (en) | 2019-04-26 | 2023-09-12 | 株式会社片岡製作所 | Cell culture substrate, cell culture container, cell culture method, cell manufacturing method, cell culture substrate manufacturing method, and cell culture container manufacturing method |
| FI129870B (en) * | 2020-04-01 | 2022-10-14 | Kesla Oyj | Chain saw |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5709254A (en) * | 1996-06-18 | 1998-01-20 | Argue; Fletcher | Tree harvesting apparatus |
| SE512961C2 (en) * | 1997-02-06 | 2000-06-12 | Sisu Logging Ab | Valve means for tensioning the saw chain |
| SE512962C2 (en) * | 1998-02-20 | 2000-06-12 | Sisu Logging Ab | Hydraulic saw chain covering means |
| US6560879B2 (en) * | 2001-08-02 | 2003-05-13 | Wci Outdoor Products, Inc. | Chain saw adjuster |
| US20040181951A1 (en) * | 2003-03-17 | 2004-09-23 | Wittke Edward R. | Chain saw safety system |
| DE20319743U1 (en) * | 2003-10-24 | 2005-03-10 | Dolmar Gmbh | Chain saw blade monitor has a sensor system that monitors the chain tension and is coupled to data processing unit |
| AT508397B1 (en) * | 2009-06-25 | 2011-04-15 | Prinz Gmbh & Co Kg | CHAINSAW |
-
2013
- 2013-09-12 NZ NZ61544413A patent/NZ615444A/en unknown
-
2014
- 2014-09-11 WO PCT/NZ2014/000197 patent/WO2015038011A1/en active Application Filing
- 2014-09-11 CA CA2923446A patent/CA2923446C/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11400530B2 (en) | 2017-06-09 | 2022-08-02 | Husqvarna Ab | Chainsaw and method |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2015038011A1 (en) | 2015-03-19 |
| NZ615444A (en) | 2014-12-24 |
| CA2923446C (en) | 2021-06-08 |
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