CA1221006A - Saw type tree felling head and method of felling trees utilizing a felling head - Google Patents
Saw type tree felling head and method of felling trees utilizing a felling headInfo
- Publication number
- CA1221006A CA1221006A CA000428574A CA428574A CA1221006A CA 1221006 A CA1221006 A CA 1221006A CA 000428574 A CA000428574 A CA 000428574A CA 428574 A CA428574 A CA 428574A CA 1221006 A CA1221006 A CA 1221006A
- Authority
- CA
- Canada
- Prior art keywords
- tree
- arm
- frame
- saw
- felling head
- Prior art date
- 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.)
- Expired
Links
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
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Biodiversity & Conservation Biology (AREA)
- Ecology (AREA)
- Forests & Forestry (AREA)
- Environmental Sciences (AREA)
- Shovels (AREA)
Abstract
ABSTRACT
A method of felling trees and a felling head for doing the same. The method involves driving a horizontally sharpened blade on the felling head partially into a tree from one side and applying a selected force to the opposite side of the tree at a position above the cutting member, moving a driven saw on the felling head through the tree to cut the same and immediately the tree has been cut, shifting the same laterally onto a support plate. The apparatus includes a frame having a hydraulically operated sweep arm pivotally mounted on the frame for movement toward and away from an area in which the trees are collected and a plate on the frame for supporting the butt ends of the trees. The plate has a sharpened edge for penetrating a standing tree to be cut and an arm is mounted on the frame and movable toward and away from the cutting member so as to press the cutting member partially into the tree. A hydraulically driven chain saw is mounted on such arm and hydraulically operated for cutting through the tree as it is pressed against by the sweep arm.
A method of felling trees and a felling head for doing the same. The method involves driving a horizontally sharpened blade on the felling head partially into a tree from one side and applying a selected force to the opposite side of the tree at a position above the cutting member, moving a driven saw on the felling head through the tree to cut the same and immediately the tree has been cut, shifting the same laterally onto a support plate. The apparatus includes a frame having a hydraulically operated sweep arm pivotally mounted on the frame for movement toward and away from an area in which the trees are collected and a plate on the frame for supporting the butt ends of the trees. The plate has a sharpened edge for penetrating a standing tree to be cut and an arm is mounted on the frame and movable toward and away from the cutting member so as to press the cutting member partially into the tree. A hydraulically driven chain saw is mounted on such arm and hydraulically operated for cutting through the tree as it is pressed against by the sweep arm.
Description
~22~
TITLE OF INVENTION
. _ _ SAW TYPE TREE FELLING HEAD ~ND METHOD OF FELLING
TREES UTILI~ING A FELLING HEAD
FIELD OF INVENTION
_~ _ __ This invention relates generally to tree felling heads and more particularly to impxovements in felling heads of the type utilizing a saw for cu-tting the tree and a method of felling trees utilizing the same.
BACKGROUND OF INVENTION
Tree felling heads are well known in the art and comprise generally a frame having a grapple mounted thereon for grasping the tree and severing means for cutting the tree at a position below the grapple. Various different severing devices are known and have been proposed including shears, chain saws and circular saws. Shear severing devices have been proven to be fast and rugged for felling trees and require relatively little maintenance. There is, however, considerable concern as to the damage caused to the tree resulting in substantial wastage at the butt end and which is a valuable part of the tree. ~aws, on the other hand, whether they be circular blades or chain saws, casue substantially less damage but they are fragile devices requiring frequent sharpening, maintenance and/or replacement. They are thus considered more costly than shears.
A principal drawback with saw type tree felling devices is binding of the saw during severing of the ~2~06 standing tree. To overcome this, pusher arms have been used as, for example, disclosed in Canadian Patent 898,661 issued April 25, 1972 to Per G. Mellgren, or U. S. Patent
TITLE OF INVENTION
. _ _ SAW TYPE TREE FELLING HEAD ~ND METHOD OF FELLING
TREES UTILI~ING A FELLING HEAD
FIELD OF INVENTION
_~ _ __ This invention relates generally to tree felling heads and more particularly to impxovements in felling heads of the type utilizing a saw for cu-tting the tree and a method of felling trees utilizing the same.
BACKGROUND OF INVENTION
Tree felling heads are well known in the art and comprise generally a frame having a grapple mounted thereon for grasping the tree and severing means for cutting the tree at a position below the grapple. Various different severing devices are known and have been proposed including shears, chain saws and circular saws. Shear severing devices have been proven to be fast and rugged for felling trees and require relatively little maintenance. There is, however, considerable concern as to the damage caused to the tree resulting in substantial wastage at the butt end and which is a valuable part of the tree. ~aws, on the other hand, whether they be circular blades or chain saws, casue substantially less damage but they are fragile devices requiring frequent sharpening, maintenance and/or replacement. They are thus considered more costly than shears.
A principal drawback with saw type tree felling devices is binding of the saw during severing of the ~2~06 standing tree. To overcome this, pusher arms have been used as, for example, disclosed in Canadian Patent 898,661 issued April 25, 1972 to Per G. Mellgren, or U. S. Patent
2,341,035 issued February 8, 1944 to P. ~rzelak. The pusher arm presses against the tree in the direction of cut forcing the tree to be tilted so as to avoid binding during the severing operation. This, however, is not completely accomplished. When the saw makes the final cut through the tree, the tree thereafter is not supported and rests on the saw blade causing damage thereto or binding of the same.
Felling heads incorporating a circular saw or chain saw are known in the art and while they have the advantage of making a clean cut thrcugh a tree, they are not entirely satisfactory in their present design. Often the tree will slip downwardly in the grapple after it has been severed causing binding of the saw and/or damage to the saw.
Another major drawback of felling heads incorporat-ing a circular saw or chain saw is that the tree is firmlygripped by a grapple on the felling head whereafter the tree is cut by the severing device. Firmly gripping the tree by the grapple can cause strain on the tree, tilting it from its normal growing position and which will result in damage to the tree during severing and/or binding of the saw.
SUMMARY OF INVENTION
_ .
A principal object of the present invention is to provide a felling head having a saw for severing a tree and positive means for supporting the tree such that it can not slip downwardly in the grapple after it has been severed from its roots.
Another object of the present invention is to provide a tree felling head having a saw with means for supporting the tree during a severing operation and means for stabilizing the tree without resorting to the use of a grapple firmly gripping the same.
In accordance with one aspect of applicant's invention there is provided a method of felling trees using a felling head having a saw movably mounted thereon comprising driving a horizontally disposed sharpened blade on the felling head partially into the tree from one side thereof, applying a selected force to the opposite side of the tree at a position above the cutting member, moving a driven saw on the felling head through the tree to cut the same and laterally sliding the severed tree, while in its vertical position, onto a support plate. In the preferred embodiment of the invention, the driven saw is moved through the tree in a direction of the force being applied to the tree at a position above the sharpened blade.
In accordance with another aspect of the present invention, there is provided a tree felling head comprising a frame, a sweep arm mounted on said frame for pressing ~2x~La)~
against the standing tree from one side thereof, a plate mounted on said frame and having a sharpened edge for penetrating into the trunk of the standing tree at a position below the sweep arm and on a side of the tree opposite to that of the sweep arm and a saw movably mounted on the frame for cutting through the standing tree in a plane in close proximity to that of said plate.
Applicant's invention is particularly directed to a modification to Canadian patent 1,103,130 issued June 16, 1981 and entitled "Accumulator Felling ~ead". In the patented structure there is an accumulator type grapple and a pair of shear blades for severing the tree at a position below the grapple~ One shear blade is fixed to the frame of the felling head and a flat plate extends rearwardly there-from laterally across the felling head providing an areafor accumulating trees and supporting the butt end of the accumulated trees. The other shear blade is mounted on an arm pivotally attached to the frame and is movable in a direction toward and away from the fixed shear blade. In the present invention, the movable shear blade is replaced by a chain saw pivotally mounted on the arm. When a standing tree is to be cut the arm is pivoted towards the fixed shear blade and sufficient force applied as to cause the fixed shear blade to partially penetrate into the tree.
A sweep arm or sweep arms on the frame are pivoted to press against the tree at a position above the fixed shear blade and on an opposite side of the tree. Thereafter, the ~2~
driven saw is plvoted to cut through the tree in a plane in near proximity to that of the shear blade. When the tree has been cut through, the fixed shear blade supports the tree and thus avoids any damage to the saw blade since the tree can not move downwardly as is the case with prior art devices. The continual pressure applied by the sweep arm to the tree avoids any binding of the saw during cutting and immediately the tree has been severed the sweep arms move the tree laterally into the tree accumulating area where it is firmly held by the accumulator grapple arms.
Preferably, the upper edge cut through the tree by the chain saw is slightly below the upper surface of the fixed plate so that when the tree is moved laterally it is also raised slightly, thereby preventing any binding of the saw. For this purpose the taper on the fixed shear blade should extend slightly beyond the depth of penetration of the shear blade into the tree when cutting a standing tree.
LIST OF DRAWINGS
The invention is illustrated by way of example with reference to the accompanying drawings wherein:
Figure 1 is an oblique view of the felling head disclosed in applicant's aforementioned Canadian patent;
Figure 2 is an oblique view of the lower end of the felling head illustrating the major components detached and forming the severing device and tree support plate;
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Figure 3 is an oblique v:iew of a chain saw unit that can be substituted directly for the movable shear blade on the felling heads illustrated in Figures 1 and 2;
Figure 4 is an elevational diagrammatic view illustrating cutting a standing tree with a device provided in accordance with the present invention; and Figure 5 is a schematic of the hydraulic circuit for the felling head having the chain saw unit mounted thereon.
DESCRIPTION OF PREFERRED EMBODIMENT
In Figure 1 there is illustrated a tree felling head disclosed in applicant's aforementioned Canadian patent 1,103,130. Figure 2 is a partial view of the lower end of such felling head representing the commercial embodiment.
The felling head comprises a frame unit 10 pivotally attachable in a conventional manner by means on the end of an extendible and retractable boom on a mobile vehicle.
At the upper end of the frame there is an arcuate arm 11 and at the lower end of the frame a plate 12 having a corresponding arcuate tree retaining arm 13 for retaining a tree or a plurality of trees severed by the shear severing mechanism. Trees severed are retained in the accumulating area by articulated arms 14 pivotally attached to the frame by pin 15 and consist of a first arm 16 and a finger member 17 pivotally attached thereto by pin 18.
The arm 16 and finger member 17 are actuated by an hydraulic cylinder unit 18 and link unit 19. The tree support plate 12 has a shear blade 20 attached thereto with a sharpened edge 21 and which cooperates with a shear blade 22 mounted on a pivoted arm 23 for severing the tree. The arm 23 is pivotally attached to the frame by means of a pivot pin 24 and moved by an hydraulic cylinder unit 25 (see Figure 3)O A standing tree severed by the shear blades 20 and 22 is swept from the shear blades onto the tree supporting plate 12 by a sweep arm unit 26 which may be a single arm or an upper and lower arm as illustrated in the drawing. Movement of the sweep arm is effected by hydraulic cylinder unit 27 shown in Figure 1 or a pair of cylinders 27A and 27s shown in Figure 5. The articulated arm 14 la single arm or an upper arm and lower pair of arms as illustrated in Figure 1) is selectively moved by the single cylinder 18 shown in Figure 1 or respective ones of a pair of hydraulic cylinder units 18A and 18B illustrated in Figure 5 and the finger arms 15 are pivotally moved by the links 19. For further details on the same, reference may be had to applicant's aforementioned Canadian patent.
In Figure 3 there is illustrated an arm 23A
which can be substituted for the arm 23 illustrated in Figures 1 and 2 and pivotally attached to the frame 10 by pivot pin 24 passing through bushing 30 in the arm 23A.
The arm 23A is connected to the hydraulic cylinder 25 (which at the other end is anchored to frame 10) and moved thereby about pivot pin 24 in a direction toward ~L22~00~
and away from the blade 20 having the sharpened cutting edge 21. The arm 23A is channel shaped in cross-se~tion with the open part of the channel facing blade 20.
Pivotally mounted on bushing 30 is a power driven chain saw 40 pivotally moved about journal 30 by an hydraulic cylinder unit 41. The arm 23A has a pair of spaced apart plates 28 and 29 (see Figure 4) disposed respectively above and below the chain saw unit defining a channel in which the chain saw and bar is located prior to a cutting operation. Plates 28 and/or 29 may have a flat edge for engaging the tree. Alternatively, plate 28 may have a sharpened or serrated edge 28A and/or plate 29 may have a sharpened or serrated edge 29A for penetrating into the surface of the tree prior to a cutting operation when the tree is clampingly engaged between cutting member 20 and arm 23A. Before cutting of the tree is commenced, the tree is clampingly engaged between the cutting blade 20 and the arm 23A and with sufficient force on arm 23A as to cause cutting edge 21 of plate 12 to penetrate the tree as illustrated in Figure 4. In the event plates 28 and/or 29 are provided with a sharpened edge, during such clamping such edges would penetrate the tree stabili~ing the entire felling head unit on the standing tree. At the same time and before cutting of the tree has commenced, sweep arm 26 is swung against the tree and biased with a selected force so as to press the tree in the direction of the tree collecting or accumulating area on the felling ~22~ 6 head. When the tree is firmly grapsed between the arm 23A and shear blade 20 the chain saw is activated and pivoted by cylinder 41 so as to move the saw through the tree cutting the same. When the tree has been completely severed from its roots it is shifted laterally by sweep arm 36 onto support or butt plate 12.
A schematic of the hydraulics for the felling head with the saw attachment of Figure 3 is illustrated in Figure 5. In referring to such Figure, there is illustrated a pair of hydraulic cylinder units 18A and 18s that actuate the arms 16 of the tree accumulating mechanism. A pair of hydraulic cylinders 27A and 27B actuate the sweep arm 26 and operate in conjunction with hydraulic cylinder 25 that causes the arm 23A to move forward so as to grasp the -tree between such arm and the shear blade on the accumulating side of the felling head. A hydraulic motor M drives the chain saw and actuation thereof is controlled by a sequence valve SV which causes the same to operate when the pressure in cylinder 25 builds up to a predetermined level. The severing pass of the saw, i.e. movement of the saw blade through the tree, is effected by hydraulic cylinder 41 under the control of a solenoid operated valve 42. Oil supply for this purpose is taken from the exhaust side of motor M by way of line 43 under system back pressure or if required the back pressure built up by a variable pilo-t operated orifice 44. Pilot pressure for the actuation of this orifice is taken from the pressure side 1~210~)~
of the motor. Its effect is such that the size of the orifice varies inversely with the pressure, thus bringing about maximum cutting speed at all -times. The motor M is protected by a relief valve 45 and reversal of the motor's operation is prevented by a check valve 46. The broken lines 47 are drain lines and bring together the drainage from the sequence valve SV, the motor M and the exhaust from cylinder 41. Lubrication for the chain of the chain saw is taken from this circuit and fed to the saw in an appropriate manner from a nozzle or orifice 48. The hydraulic cylinder unit 41 controlling movement of the chain saw in its pass through the tree is a combination hydraulic cylinder accumulator unit. A compressible gas or spring is used as a spring means causing the chain saw to retract into the housing upon completion of its cut through the tree.
In order to convert the felling head from a shear to a saw severing device, pin 24 is removed and the pivotal connection of cylinder 25 to the arm is disconnected.
The arm 23 is then replaced with arm 23A illustrated in Figure 3 and the cylinder 25 connected thereto. For the chain saw arm attachment a smaller cylinder can be used than that used for the shear blade arm of Figure 1. In the hydraulic system oil initially flows to the saw arm cylinder 25 which in turn brings the arm assembly forward so that the tree to be cut is trapped beween the arm and the fixed shear blade 20. The sweep arms 26 move at the ~;~2'L~6 same time as the saw arm and when the pressure builds up to a selected setting (preferably above 1,000 p.s.i.) the oil flow shifts via sequence valve 41 to the hydraulic motor which in turn starts the chain moving on the chain saw bar.
The return line from the motor is linked up with the rod end line from the saw arm cylinder. The check valve 46 in the circuit prevents the saw motor from running in reverse. The drain line 47 directly to tank provides a very low pressure line to relieve the saw motor case, the lo sequence valve and the saw bar cyllnder.
The saw arm movement is effected by the small hydraulic cylinder 41. Such cylinder, as previously mentioned, incorporates therein a gas section the pressure of which is used to retain the bar in the shelter of the channel provided in the arm.
From the foregoing, it can be seen the apparatus when severing a tree does not grasp the tree but instead applies pressure from one side thereof by sweep arms 26 pushing the tree generally in the direction of the tree accumulating area. When making a cut with the chain saw this has a tendency to open up the cut and thus avoid binding of the saw. The cutting plane of the saw may be in line with the shear blade 20 or, alternatively, slightly therebelow. In having the saw slightly below the fixed shear blade and by having an appropriate tapered edge for the blade, i.e. one that is perhaps longer than the depth of penetration, it not only acts as a blade to penetrate the ~2Z1~
tree but also a wedge for lifting the tree. The tree, after it is severed, is swept into the accumulating area and by moving up the sharpened edge of the cutting blade this causes the tree to be lifted slightly as it is moved laterally into the collecting area. This obviously moves the butt end of the tree away from the saw preventing any damage to the saw after the cut has been completed.
In cutting large trees the accumulator arms may be removed as on large trees only a single tree would be handled at one time. In this case a tree which has been cut would be moved laterally by the sweep arm 26 onto plate 12 and a~ainst arcuate arm 11 and the arcua-te wall 13. The sweep arm would be then utilized to retain the tree in such area until it has been felled.
Anyone skilled in the art will realize from the hydraulic circuit shown in Figure 5 that as cutting becomes more difficult for Motor M there will be a pressure increase to the motor M and cylinder 27. The increased pressure in the latter will cause sweep arm 26 to apply more pressure to the tree, widening the kerf, thus decreasing any tendency to bind.
The variable orifice 44 is an optional feature as there may be sufficient system back pressure to accomplish the same results. Pilot pressure from the pressure side of the motor causes the orifice size and thus the back pressure which it creates to vary inversely with the pressure demands of the motor and thus the pressure applied by cylinder 91 will also vary inversely.
Felling heads incorporating a circular saw or chain saw are known in the art and while they have the advantage of making a clean cut thrcugh a tree, they are not entirely satisfactory in their present design. Often the tree will slip downwardly in the grapple after it has been severed causing binding of the saw and/or damage to the saw.
Another major drawback of felling heads incorporat-ing a circular saw or chain saw is that the tree is firmlygripped by a grapple on the felling head whereafter the tree is cut by the severing device. Firmly gripping the tree by the grapple can cause strain on the tree, tilting it from its normal growing position and which will result in damage to the tree during severing and/or binding of the saw.
SUMMARY OF INVENTION
_ .
A principal object of the present invention is to provide a felling head having a saw for severing a tree and positive means for supporting the tree such that it can not slip downwardly in the grapple after it has been severed from its roots.
Another object of the present invention is to provide a tree felling head having a saw with means for supporting the tree during a severing operation and means for stabilizing the tree without resorting to the use of a grapple firmly gripping the same.
In accordance with one aspect of applicant's invention there is provided a method of felling trees using a felling head having a saw movably mounted thereon comprising driving a horizontally disposed sharpened blade on the felling head partially into the tree from one side thereof, applying a selected force to the opposite side of the tree at a position above the cutting member, moving a driven saw on the felling head through the tree to cut the same and laterally sliding the severed tree, while in its vertical position, onto a support plate. In the preferred embodiment of the invention, the driven saw is moved through the tree in a direction of the force being applied to the tree at a position above the sharpened blade.
In accordance with another aspect of the present invention, there is provided a tree felling head comprising a frame, a sweep arm mounted on said frame for pressing ~2x~La)~
against the standing tree from one side thereof, a plate mounted on said frame and having a sharpened edge for penetrating into the trunk of the standing tree at a position below the sweep arm and on a side of the tree opposite to that of the sweep arm and a saw movably mounted on the frame for cutting through the standing tree in a plane in close proximity to that of said plate.
Applicant's invention is particularly directed to a modification to Canadian patent 1,103,130 issued June 16, 1981 and entitled "Accumulator Felling ~ead". In the patented structure there is an accumulator type grapple and a pair of shear blades for severing the tree at a position below the grapple~ One shear blade is fixed to the frame of the felling head and a flat plate extends rearwardly there-from laterally across the felling head providing an areafor accumulating trees and supporting the butt end of the accumulated trees. The other shear blade is mounted on an arm pivotally attached to the frame and is movable in a direction toward and away from the fixed shear blade. In the present invention, the movable shear blade is replaced by a chain saw pivotally mounted on the arm. When a standing tree is to be cut the arm is pivoted towards the fixed shear blade and sufficient force applied as to cause the fixed shear blade to partially penetrate into the tree.
A sweep arm or sweep arms on the frame are pivoted to press against the tree at a position above the fixed shear blade and on an opposite side of the tree. Thereafter, the ~2~
driven saw is plvoted to cut through the tree in a plane in near proximity to that of the shear blade. When the tree has been cut through, the fixed shear blade supports the tree and thus avoids any damage to the saw blade since the tree can not move downwardly as is the case with prior art devices. The continual pressure applied by the sweep arm to the tree avoids any binding of the saw during cutting and immediately the tree has been severed the sweep arms move the tree laterally into the tree accumulating area where it is firmly held by the accumulator grapple arms.
Preferably, the upper edge cut through the tree by the chain saw is slightly below the upper surface of the fixed plate so that when the tree is moved laterally it is also raised slightly, thereby preventing any binding of the saw. For this purpose the taper on the fixed shear blade should extend slightly beyond the depth of penetration of the shear blade into the tree when cutting a standing tree.
LIST OF DRAWINGS
The invention is illustrated by way of example with reference to the accompanying drawings wherein:
Figure 1 is an oblique view of the felling head disclosed in applicant's aforementioned Canadian patent;
Figure 2 is an oblique view of the lower end of the felling head illustrating the major components detached and forming the severing device and tree support plate;
~22~0~3~
Figure 3 is an oblique v:iew of a chain saw unit that can be substituted directly for the movable shear blade on the felling heads illustrated in Figures 1 and 2;
Figure 4 is an elevational diagrammatic view illustrating cutting a standing tree with a device provided in accordance with the present invention; and Figure 5 is a schematic of the hydraulic circuit for the felling head having the chain saw unit mounted thereon.
DESCRIPTION OF PREFERRED EMBODIMENT
In Figure 1 there is illustrated a tree felling head disclosed in applicant's aforementioned Canadian patent 1,103,130. Figure 2 is a partial view of the lower end of such felling head representing the commercial embodiment.
The felling head comprises a frame unit 10 pivotally attachable in a conventional manner by means on the end of an extendible and retractable boom on a mobile vehicle.
At the upper end of the frame there is an arcuate arm 11 and at the lower end of the frame a plate 12 having a corresponding arcuate tree retaining arm 13 for retaining a tree or a plurality of trees severed by the shear severing mechanism. Trees severed are retained in the accumulating area by articulated arms 14 pivotally attached to the frame by pin 15 and consist of a first arm 16 and a finger member 17 pivotally attached thereto by pin 18.
The arm 16 and finger member 17 are actuated by an hydraulic cylinder unit 18 and link unit 19. The tree support plate 12 has a shear blade 20 attached thereto with a sharpened edge 21 and which cooperates with a shear blade 22 mounted on a pivoted arm 23 for severing the tree. The arm 23 is pivotally attached to the frame by means of a pivot pin 24 and moved by an hydraulic cylinder unit 25 (see Figure 3)O A standing tree severed by the shear blades 20 and 22 is swept from the shear blades onto the tree supporting plate 12 by a sweep arm unit 26 which may be a single arm or an upper and lower arm as illustrated in the drawing. Movement of the sweep arm is effected by hydraulic cylinder unit 27 shown in Figure 1 or a pair of cylinders 27A and 27s shown in Figure 5. The articulated arm 14 la single arm or an upper arm and lower pair of arms as illustrated in Figure 1) is selectively moved by the single cylinder 18 shown in Figure 1 or respective ones of a pair of hydraulic cylinder units 18A and 18B illustrated in Figure 5 and the finger arms 15 are pivotally moved by the links 19. For further details on the same, reference may be had to applicant's aforementioned Canadian patent.
In Figure 3 there is illustrated an arm 23A
which can be substituted for the arm 23 illustrated in Figures 1 and 2 and pivotally attached to the frame 10 by pivot pin 24 passing through bushing 30 in the arm 23A.
The arm 23A is connected to the hydraulic cylinder 25 (which at the other end is anchored to frame 10) and moved thereby about pivot pin 24 in a direction toward ~L22~00~
and away from the blade 20 having the sharpened cutting edge 21. The arm 23A is channel shaped in cross-se~tion with the open part of the channel facing blade 20.
Pivotally mounted on bushing 30 is a power driven chain saw 40 pivotally moved about journal 30 by an hydraulic cylinder unit 41. The arm 23A has a pair of spaced apart plates 28 and 29 (see Figure 4) disposed respectively above and below the chain saw unit defining a channel in which the chain saw and bar is located prior to a cutting operation. Plates 28 and/or 29 may have a flat edge for engaging the tree. Alternatively, plate 28 may have a sharpened or serrated edge 28A and/or plate 29 may have a sharpened or serrated edge 29A for penetrating into the surface of the tree prior to a cutting operation when the tree is clampingly engaged between cutting member 20 and arm 23A. Before cutting of the tree is commenced, the tree is clampingly engaged between the cutting blade 20 and the arm 23A and with sufficient force on arm 23A as to cause cutting edge 21 of plate 12 to penetrate the tree as illustrated in Figure 4. In the event plates 28 and/or 29 are provided with a sharpened edge, during such clamping such edges would penetrate the tree stabili~ing the entire felling head unit on the standing tree. At the same time and before cutting of the tree has commenced, sweep arm 26 is swung against the tree and biased with a selected force so as to press the tree in the direction of the tree collecting or accumulating area on the felling ~22~ 6 head. When the tree is firmly grapsed between the arm 23A and shear blade 20 the chain saw is activated and pivoted by cylinder 41 so as to move the saw through the tree cutting the same. When the tree has been completely severed from its roots it is shifted laterally by sweep arm 36 onto support or butt plate 12.
A schematic of the hydraulics for the felling head with the saw attachment of Figure 3 is illustrated in Figure 5. In referring to such Figure, there is illustrated a pair of hydraulic cylinder units 18A and 18s that actuate the arms 16 of the tree accumulating mechanism. A pair of hydraulic cylinders 27A and 27B actuate the sweep arm 26 and operate in conjunction with hydraulic cylinder 25 that causes the arm 23A to move forward so as to grasp the -tree between such arm and the shear blade on the accumulating side of the felling head. A hydraulic motor M drives the chain saw and actuation thereof is controlled by a sequence valve SV which causes the same to operate when the pressure in cylinder 25 builds up to a predetermined level. The severing pass of the saw, i.e. movement of the saw blade through the tree, is effected by hydraulic cylinder 41 under the control of a solenoid operated valve 42. Oil supply for this purpose is taken from the exhaust side of motor M by way of line 43 under system back pressure or if required the back pressure built up by a variable pilo-t operated orifice 44. Pilot pressure for the actuation of this orifice is taken from the pressure side 1~210~)~
of the motor. Its effect is such that the size of the orifice varies inversely with the pressure, thus bringing about maximum cutting speed at all -times. The motor M is protected by a relief valve 45 and reversal of the motor's operation is prevented by a check valve 46. The broken lines 47 are drain lines and bring together the drainage from the sequence valve SV, the motor M and the exhaust from cylinder 41. Lubrication for the chain of the chain saw is taken from this circuit and fed to the saw in an appropriate manner from a nozzle or orifice 48. The hydraulic cylinder unit 41 controlling movement of the chain saw in its pass through the tree is a combination hydraulic cylinder accumulator unit. A compressible gas or spring is used as a spring means causing the chain saw to retract into the housing upon completion of its cut through the tree.
In order to convert the felling head from a shear to a saw severing device, pin 24 is removed and the pivotal connection of cylinder 25 to the arm is disconnected.
The arm 23 is then replaced with arm 23A illustrated in Figure 3 and the cylinder 25 connected thereto. For the chain saw arm attachment a smaller cylinder can be used than that used for the shear blade arm of Figure 1. In the hydraulic system oil initially flows to the saw arm cylinder 25 which in turn brings the arm assembly forward so that the tree to be cut is trapped beween the arm and the fixed shear blade 20. The sweep arms 26 move at the ~;~2'L~6 same time as the saw arm and when the pressure builds up to a selected setting (preferably above 1,000 p.s.i.) the oil flow shifts via sequence valve 41 to the hydraulic motor which in turn starts the chain moving on the chain saw bar.
The return line from the motor is linked up with the rod end line from the saw arm cylinder. The check valve 46 in the circuit prevents the saw motor from running in reverse. The drain line 47 directly to tank provides a very low pressure line to relieve the saw motor case, the lo sequence valve and the saw bar cyllnder.
The saw arm movement is effected by the small hydraulic cylinder 41. Such cylinder, as previously mentioned, incorporates therein a gas section the pressure of which is used to retain the bar in the shelter of the channel provided in the arm.
From the foregoing, it can be seen the apparatus when severing a tree does not grasp the tree but instead applies pressure from one side thereof by sweep arms 26 pushing the tree generally in the direction of the tree accumulating area. When making a cut with the chain saw this has a tendency to open up the cut and thus avoid binding of the saw. The cutting plane of the saw may be in line with the shear blade 20 or, alternatively, slightly therebelow. In having the saw slightly below the fixed shear blade and by having an appropriate tapered edge for the blade, i.e. one that is perhaps longer than the depth of penetration, it not only acts as a blade to penetrate the ~2Z1~
tree but also a wedge for lifting the tree. The tree, after it is severed, is swept into the accumulating area and by moving up the sharpened edge of the cutting blade this causes the tree to be lifted slightly as it is moved laterally into the collecting area. This obviously moves the butt end of the tree away from the saw preventing any damage to the saw after the cut has been completed.
In cutting large trees the accumulator arms may be removed as on large trees only a single tree would be handled at one time. In this case a tree which has been cut would be moved laterally by the sweep arm 26 onto plate 12 and a~ainst arcuate arm 11 and the arcua-te wall 13. The sweep arm would be then utilized to retain the tree in such area until it has been felled.
Anyone skilled in the art will realize from the hydraulic circuit shown in Figure 5 that as cutting becomes more difficult for Motor M there will be a pressure increase to the motor M and cylinder 27. The increased pressure in the latter will cause sweep arm 26 to apply more pressure to the tree, widening the kerf, thus decreasing any tendency to bind.
The variable orifice 44 is an optional feature as there may be sufficient system back pressure to accomplish the same results. Pilot pressure from the pressure side of the motor causes the orifice size and thus the back pressure which it creates to vary inversely with the pressure demands of the motor and thus the pressure applied by cylinder 91 will also vary inversely.
Claims (19)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of felling trees using a felling head having a saw movably mounted thereon comprising:
(a) driving a horizontally disposed sharpened blade on the felling head partially into the tree from one side thereof;
(b) applying a selected force to the opposite side of the tree at a position above the cutting member;
(c) moving a driven saw on the felling head through the tree to cut the same at a position below the blade member;
and (d) shifting the tree laterally immediately it has been cut onto a plate to support the butt end of the tree.
(a) driving a horizontally disposed sharpened blade on the felling head partially into the tree from one side thereof;
(b) applying a selected force to the opposite side of the tree at a position above the cutting member;
(c) moving a driven saw on the felling head through the tree to cut the same at a position below the blade member;
and (d) shifting the tree laterally immediately it has been cut onto a plate to support the butt end of the tree.
2. A method as defined in Claim 1 wherein the driven saw is moved through the tree in a direction of the force being applied to the tree at said position above the sharpened blade.
3. A method of cutting a standing tree comprising:
(a) grasping the tree to be cut between a pair of members on a tree felling head and at least one of which has a sharpened cutting edge;
(b) applying sufficient force to said members so as to cause the sharpened cutting edge to partially penetrate the tree; and (c) moving a driven saw cutting member on the tree felling head through the tree at a position slightly below the member having the sharpened cutting edge.
(a) grasping the tree to be cut between a pair of members on a tree felling head and at least one of which has a sharpened cutting edge;
(b) applying sufficient force to said members so as to cause the sharpened cutting edge to partially penetrate the tree; and (c) moving a driven saw cutting member on the tree felling head through the tree at a position slightly below the member having the sharpened cutting edge.
4. A method as defined in Claim 3 including the step of applying a force to the tree at a position above the cutting member and in the direction of movement of the same during cutting of the tree.
5. A tree felling head comprising:
(a) a frame;
(b) a sweep arm mounted on said frame for pressing against a standing tree from one side thereof;
(c) a plate mounted on said frame and having a sharpened edge for penetrating into the trunk of the standing tree at a position below the sweep arm and on a side of the tree opposite to that of the sweep arm; and (d) a saw movably mounted on the frame for cutting through the standing tree at a position below said plate.
(a) a frame;
(b) a sweep arm mounted on said frame for pressing against a standing tree from one side thereof;
(c) a plate mounted on said frame and having a sharpened edge for penetrating into the trunk of the standing tree at a position below the sweep arm and on a side of the tree opposite to that of the sweep arm; and (d) a saw movably mounted on the frame for cutting through the standing tree at a position below said plate.
6. A tree felling head as defined in Claim 5 wherein said saw is mounted on an arm pivotally attached to said frame and wherein said saw is movably mounted on said arm.
7. A tree felling head as defined in Claim 6 wherein said arm has a sharpened edge for penetrating a standing tree.
8. A tree felling head as defined in Claim 7 wherein the sharpened edge on said arm penetrates the tree at a position above a cut made therethrough by the saw.
9. A tree felling head as defined in Claim 7 wherein the sharpened edge on said arm penetrates the tree at a position below a cut made therethrough by the saw.
10. A tree felling head as defined in Claim 7 wherein sharpened edges on said arm penetrate the tree above and below a cut made therethrough by the saw.
11. A tree felling head as defined in Claims 5, 6 or 7 wherein said saw is a chain saw.
12. A tree felling head comprising:
(a) a frame;
(b) an hydraulically operated tree accumulating grapple mechanism mounted on said frame;
(c) an hydraulically operated sweep arm pivotally mounted on the frame for movement toward and away from the tree accumulating grapple mechanism;
(d) a plate mounted on said frame for supporting the butt ends of trees retained in the accumulating grapple mechanism, said plate having a sharpened edge for penetrating a standing tree to be cut;
(e) an hydraulically operated second arm pivotally mounted on the frame for movement in a direction toward and away from the sharpened edge of said plate;
(f) an hydraulically driven chain saw pivotally mounted on said arm; and (g) hydraulic means for pivotally moving said chain saw.
(a) a frame;
(b) an hydraulically operated tree accumulating grapple mechanism mounted on said frame;
(c) an hydraulically operated sweep arm pivotally mounted on the frame for movement toward and away from the tree accumulating grapple mechanism;
(d) a plate mounted on said frame for supporting the butt ends of trees retained in the accumulating grapple mechanism, said plate having a sharpened edge for penetrating a standing tree to be cut;
(e) an hydraulically operated second arm pivotally mounted on the frame for movement in a direction toward and away from the sharpened edge of said plate;
(f) an hydraulically driven chain saw pivotally mounted on said arm; and (g) hydraulic means for pivotally moving said chain saw.
13. A tree felling head as defined in Claim 12 wherein hydraulic cylinders for the sweep arm and second arm are controlled by hydraulic pressure from a common line and wherein said common line is connected to the hydraulic motor for the chain saw through a sequence valve arranged so that such motor commences operation after the pressure in the common line reaches a predetermined level.
14. A tree felling head comprising:
(a) a frame;
(b) an hydraulically operated tree accumulating grapple mechanism mounted on said frame;
(c) an hydraulically operated sweep arm pivotally mounted on the frame for swinging movement toward and away from the tree accumulating grapple mechanism;
(d) a plate mounted on said frame adjacent a lower end thereof and extending in a direction laterally thereacross for supporting the butt ends of trees retained in the accumulating grapple mechanism, said plate having a sharpened edge for penetrating a standing tree to be cut;
(e) an hydraulically operated second arm pivotally mounted on the frame for swinging movement in a direction toward and away from the sharpened edge of said plate;
(f) an hydraulically driven chain saw pivotally mounted on said arm; and (g) hydraulic means for pivotally moving said chain saw.
(a) a frame;
(b) an hydraulically operated tree accumulating grapple mechanism mounted on said frame;
(c) an hydraulically operated sweep arm pivotally mounted on the frame for swinging movement toward and away from the tree accumulating grapple mechanism;
(d) a plate mounted on said frame adjacent a lower end thereof and extending in a direction laterally thereacross for supporting the butt ends of trees retained in the accumulating grapple mechanism, said plate having a sharpened edge for penetrating a standing tree to be cut;
(e) an hydraulically operated second arm pivotally mounted on the frame for swinging movement in a direction toward and away from the sharpened edge of said plate;
(f) an hydraulically driven chain saw pivotally mounted on said arm; and (g) hydraulic means for pivotally moving said chain saw.
15. A tree felling head as defined in Claim 12 wherein hydraulic cylinders for the sweep arm and second arm are controlled by hydraulic pressure from a common line and wherein said common line is connected to the hydraulic motor for the chain saw through a sequence valve arranged so that such motor commences operation after the pressure in the common line reaches a predetermined level whereby when a standing tree to be cut is grasped between the second arm and the blade's sharpened edge, the latter penetrates a selected depth into the tree before cutting with the chain saw commences.
16. A felling head comprising:
(a) a frame;
(b) a grapple mounted on said frame for grasping a tree; and (c) a combined saw and shear tree severing device mounted on said frame below said grapple, said severing device comprising a shear blade mounted on said frame, an arm pivotally mounted on the frame for swinging in a direction toward and away from the shear blade and a chain saw pivotally mounted for cutting through the tree at a position below the shear blade.
(a) a frame;
(b) a grapple mounted on said frame for grasping a tree; and (c) a combined saw and shear tree severing device mounted on said frame below said grapple, said severing device comprising a shear blade mounted on said frame, an arm pivotally mounted on the frame for swinging in a direction toward and away from the shear blade and a chain saw pivotally mounted for cutting through the tree at a position below the shear blade.
17. A felling head as defined in Claim 16 wherein the chain saw is pivotally mounted on said arm.
18. A felling head as defined in Claim 17 wherein said arm and chain saw are mounted on a common axis.
19. A felling head as defined in Claim 16, 17 or 18 wherein said grapple comprises one arm fixed to said frame and another sweep arm pivotally mounted on the frame for swinging in a direction toward and away from said one fixed arm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000428574A CA1221006A (en) | 1983-05-20 | 1983-05-20 | Saw type tree felling head and method of felling trees utilizing a felling head |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000428574A CA1221006A (en) | 1983-05-20 | 1983-05-20 | Saw type tree felling head and method of felling trees utilizing a felling head |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1221006A true CA1221006A (en) | 1987-04-28 |
Family
ID=4125294
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000428574A Expired CA1221006A (en) | 1983-05-20 | 1983-05-20 | Saw type tree felling head and method of felling trees utilizing a felling head |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1221006A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005099438A1 (en) * | 2004-04-16 | 2005-10-27 | Ponsse Oyj | Arrangement in wood handling device |
| CN107538573A (en) * | 2017-09-10 | 2018-01-05 | 韩朝锋 | A kind of intelligence lumbering debranching segment robot |
-
1983
- 1983-05-20 CA CA000428574A patent/CA1221006A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005099438A1 (en) * | 2004-04-16 | 2005-10-27 | Ponsse Oyj | Arrangement in wood handling device |
| CN107538573A (en) * | 2017-09-10 | 2018-01-05 | 韩朝锋 | A kind of intelligence lumbering debranching segment robot |
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| MKEX | Expiry |