Note: Descriptions are shown in the official language in which they were submitted.
CA 02590788 2007-06-07
SUSPENDABLE TREE CUTTER HAVING AN ADJUSTABLE ORIENTATION PIVOT
Field of the Invention
The present invention relates to harvesting of trees in general and in
particular
to a method and apparatus for the cutting and removal of trees through the use
of a helicopter.
Background of the Invention
Methods of cutting trees down are well known. In particular the use of hand
operated chain saws or saws manipulated by heavy machinery are commonly used.
Both of these
typical methods of cutting down trees requires access to the base of the tree.
In the case of a heavy
machine, such as, for example an excavator with a feller buncher head attached
to the distal end of
the arm requires a significant amount of free space adjacent to the base of
the tree so that the
excavator may access the tree.
Access to the base of a tree is not always available or practical. In the case
of trees
located on high or steep mountain sides, road access may not be available. In
addition, in the case
of thick forests where only a single tree is desired to be cut down, previous
methods have required
having a worker either walk to the location or be lowered to the ground from a
helicopter
proximate to the target tree. The worker may then cut down the tree using
convention methods
and the tree removed by a helicopter. This method is both expensive and time
consuming.
Conventional methods of cutting down trees also suffer from the hazard
associated
with trees that have been at least partially cut at the base but are leaning
against an adjacent tree,
which are known as snags in the art. Snags are one of the largest hazards
facing loggers today.
The extraction of a snag requires a logger to be adjacent to the base of the
snag or a supporting tree
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so as to cut one or both down. The resulting movement of the snag or the
supporting tree during
this process may cause one or more of these trees to strike the worker.
The use of mechanical harvesters or feller bunchers has reduced these risks,
although for the reasons set out above, it is not always possible to use a
harvester or a feller
buncher in all areas. In addition, on smaller logging sites, where no large
equipment is currently
being used, the cost and delay of bringing a harvester or feller buncher may
be prohibitive to their
use.
What is desirable is a method and appara.tus of cutting a tree with a
helicopter
which does not require a worker or machine on the ground. The method and
apparatus would also
desirably enable the helicopter to lift and cut a blow down or a snagged tree.
Summary of the Invention
According to a first embodiment of the present invention there is disclosed a
method
of cutting a tree using a helicopter. The method comprises providing a vehicle
suspendable cutting
apparatus comprising a gripper, a cutter and a selective orientation means.
The method further
comprises selectively orienting the cutting apparatus relative to the tree,
the gripping the tree with
the gripper and cutting the tree with the cutter.
According to a fiuther embodiment of the present invention there is disclosed
an
apparatus for cutting a tree. The apparatus comprises a frame suspendable from
a vehicle such as
a helicopter wherein the frame is selectively orientable about a horizontal
axis. A pair of opposed
gripping arms extend from the frame and are operable to selectively grip a
tree substantially
perpendicularly to the horizontal axis. A saw is rotatably connected to the
frame and is selectively
engageable against a tree secured in the gripping arms.
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The apparatus may further comprise an elongate member extending perpendicular
to the horizontal axis. The elongate member may be operable to slidably
receive a support line
from the vehicle wherein the support line may be received at a plurality of
locations along the
elongate member. Each of the plurality of locations corresponds to a unique
orientation of the
frame.
The elongate member may include first and second ends. Locating the support
line
at the first end of the elongate member may substantially align the frame to
grasp and cut a
substantially vertical tree. Locating the support line at the second end of
the elongate member may
substantially align the frame to grasp a substantially horizontal log. The
first end of the elongate
member may be disposed in a direction closer to a tree gripped between the
gripping arms than the
second end.
The elongate member may be pivotally connected the frame. The first end of the
elongate member may be secured to the frame with a flexible tension member.
The flexible
tension member may be selected from the group comprising a rope, a cable, and
a chain.
The saw may comprise a chain saw. The chain saw may be pivotally connected to
the frame. The chain saw may be rotatable about the pivot so as to be operable
to cut the tree. The
chain saw may be rotatable by a hydraulic cylinder. The chain saw may be
removable from the
frame.
The gripping arms may be pivotally connected to the frame about parallel axes.
The gripping arms may include hydraulic cylinders for moving the gripping arms
towards each
other.
The apparatus may further comprise a motor driving a hydraulic pump for
actuating
the gripping arms and saw hydraulic cylinders. The apparatus may further
comprise a hydraulic
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reservoir. The hydraulic reservoir may include a pick-up line for the
hydraulic pump on at least
one side of the reservoir.
Other aspects and features of the present invention will become apparent to
those
ordinarily skilled in the art upon review of the following description of
specific embodiments of the
invention in conjunction with the accompanying figures.
Brief Description of the Drawings
In drawings which illustrate embodiments of the invention wherein similar
characters
of reference denote corresponding parts in each view,
Figure 1 is a perspective view of a cutting apparatus according to a first
embodiment
of the present invention in a horizontal orientation suspended from a
helicopter adjacent to the base
ofatreetobecut.
Figure 2 is a perspective view of the cutting apparatus of Figure 1 in a
vertical
orientation.
Figure 3 is a bottom view of the cutting apparatus of Figure 1 with the
gripping arms
open around a tree.
Figure 4 is a bottom view of the cutting apparatus of Figure 1 with a tree
gripped
between the gripping arms.
Figure 5 is a side view of the cutting apparatus of Figure 1 resting on a
surface with
the cable support at a first position for supporting the cutting apparatus in
a horizontal orientation.
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Figure 6 is a side view of the cutting apparatus of Figure 1 resting on a
surface with
the cable support at a second position for supporting the cutting apparatus in
a vertical orientation.
Figure 7 is a side view of the cutting apparatus of Figure 1 gripping a tree
with the
cable at a second position for guiding the fall direction of the tree.
Figure 8 is a side view ofthe cutting apparatus ofFigure 1 with the cable
support at a
second position with the cutting apparatus suspended in a vertical
orientation.
Detailed Description of Embodiments of the Invention
Referring to Figure 1, a cutting apparatus according to a first embodiment of
the
invention is shown generally at 10. The cutting apparatus 10 is suspended on
the end of a line 8
from a helicopter 6 adjacent to a tree to be cut 4. Although the cutting
apparatus is illustrated as
being suspended from a helicopter in the Figures, it will be appreciated that
the cutting apparatus
may also be suspended from the end of a boom of a crane or other vehicle by a
cable, rope, chain
or other suitable line 8.
The cutting apparatusl0 comprises a frame 20 having a pair of opposed gripping
arms 50 and rotatable saw 70 supported thereon. As described further below,
the pivotal
movement of saw 70 is substantially parallel to the pivotal movement of the
gripping arms 50.
That is, a plane containing the movement of the saw is parallel to a plane
containing the movement
of the arms. The cutting apparatus also includes a pivoting slide bar 90
pivotally attached to the
frame 20 wherein the end of the line 8 is slidably connected slide bar. It
will be appreciated that
the cutting apparatus 10 may also include control wires (not shown) extending
from the cutting
apparatus to the helicopter 6 for control of the cutting apparatus by a user
in the helicopter. Radio
frequency or other remote control means may also be useful.
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Thrning now to Figure 2, the frame 20 comprises a pair of spaced apart main
plates
22a and 22b each having top and bottom edges 24 and 26, respectively and
defining a space 28
therebetween. The top edges 24 are connected to a space frame 30 comprising a
plurality of
angled members 32 extending from the top edges 24 of the main plates 22a and
22b to a top
bracket 34. The space frame 30 also includes side braces 36 extending from the
top bracket 34 to
the bottom edges 26 of the plates 22. As illustrated, the space frame 30 may
also support a motor
38, a hydraulic pump 40 and a hydraulic tank 42 as well as hydraulic hoses 43
and solenoid valves
required to operate the cutting apparatus 10 in accordance with the
functioning as described below
as will be appreciated by a person of skill in the art. The hydraulic tank 42
my include a plurality
of fluid pick-up loca.tions 45 on a plurality of sides of the tank so that
hydraulic fluid will be
available for the hydraulic pump 40 at a plurality of orientations of the
cutting apparatus 10. The
top bracket 34 comprises a pair of spaced apart bracket plates 44
perpendicularly aligned to the
main plates 22. The frame 20 may also include a plurality of braces 46
arranged between the main
plates 22 or the angled members 32 so as to provide additional rigidity to the
frame.
The gripping arms 50 extend from and are pivotally mounted to the frame 20
about
parallel axes 58. Each gripping arm 50 comprises a curved member having
proximate and distal
ends 52 and 54 respectively, and a pivot 56 intermediate the first and second
ends. It will be
appreciated that other shapes for the gripping arm will also be useful. The
pivots 56 are located
between the main plates 22 at opposite ends of the space 28 and rotatable
relative thereto about
axes 58. Actuators, such as for example hydraulic cylinders 60 extend between
the proximate ends
52 and a central brace 62 of the frame 20. The hydraulic cylinders 60 serve to
rotate the gripping
arms 50 about their axes 58 so as to selectively grip a tree 4, log or other
object to be cut
therebetween. Control of the hydraulic cylinders 60 are provided for by the
hydraulic pump 40
and solenoids as will be appreciated by a person of skill in the art from the
description of opera.tion
as provided in further detail below.
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Turning to Figure 3, a saw 70, such as for example a chain saw, is rotatably
connected to the first main plate 22a. As illustrated, the saw 70 includes a
bar 72 having a cutting
chain 73, and a motor 74 having a throttle 76. The bar 72 of the saw 70
includes a bore 79 through
which a pivot bolt 78 is passed and secured to the first main plate 22a. A
rotating hydraulic
cylinder 80 or other suitable means extends between the motor 74 of the saw
and the first main
plate 22a and serves to selectively rotate the saw about the pivot bolt 78.
The rotating hydraulic
cylinder may be secured to the motor 74 by a bolt or other suitable fastening
means such that
removal of the bolt and the pivot bolt 78 permits the saw to be removed from
the cutting
apparatus. This will facilitate the use of the saw by a ground personnel when
not in use on the
cutting apparatus 10 or when other conditions dictate. The throttle 76 of the
saw 70 may include
an electric solenoid 77 for remotely controlling the operation of the motor as
will be described
herein.
Referring back to Figure 2, the slide bar 90 comprises an elongate member
extending between first and second ends 92 and 94, respectively, a track 96
and an intermediate
pivot plate 98. The track 96 comprises an open faced c-shaped channel. The
pivot plate 98
extends from an opposite side of the elongate member from the track 96 and
includes a pivot 100
oriented substantially perpendicular to the track and spaced apart therefrom.
The pivot 100 is
spaced apart from the track 96 by a distance sufficient to permit the slide
bar to be rotated to
substantially parallel to the side braces 36 of the frame 20. As illustrated
the pivot 100 is spaced
apart from the track 96 by a distance greater than half the distance between
the main plates 22.
The track 96 contains a slidable carriage 102 located therein having bearings,
wheels or other
suitable slide means for permitting carriage 102 to freely slide within the
track 96. The carriage
102 includes a connection plate 104 having a bore 106 for securing to a line 8
suspended from
helicopter 6.
The first end 92 of the slide bar is connected to the second main plate 22b by
a
chain 108, cable or other suitable flexible securing means. The length of the
chain 108 is selected
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to permit the slide bar to rotate away from the second main plate 22b by a
distance sufficient to
align the gripping arms axes 58 substantially vertical to the ground when the
carriage 102 is
located at the second end 94 of the slide bar.
The cutting apparatus 10 may be rotated about an axis of rotation 110 between
a
horizontal orientation as illustrated in Figure 1 or a vertical orientation as
illustrated in Figure 2 by
locating the carriage 102 at the first or second ends 92 or 94, respectively,
of slide bar 90.
eration
Referring to Figures 3 and 4, in operation, a helicopter 6 suspending the
cutting
apparatus 10 positions the cutting apparatus adjacent to a tree 4 to be cut.
For cutting a tree, the
carriage 102 is located at the first end 92 of the slide bar 90 so as to
orient the cutting apparatus 10
with the gripping arms 50 substantially horizontal as illustrated in Figure 1.
The helicopter 6
positions the cutting apparatus 10 adjacent to the tree 4 with the trunk of
the tree between the
gripping arms 50. As illustrated in Figure 3, the gripping anns 50 are pivoted
about their axes 58
in directions generally indicated at A by the hydraulic cylinders 60 so as to
be moved towards each
other so as to grip the tree 4 between the gripping arms 50 and the frame 20.
After the cutting
apparatus 10 is secured to the trunk of the tree 4, the chain saw 70 is
rotated by the rotating
hydraulic cylinder 80 in a direction generally indicated at B into engagement
with the tree.
Solenoid 77 actuates the throttle 76 so as to bring the chain saw up to a
suitable cutting speed. The
rotating hydraulic cylinder 80 continues to rotate the chain saw 70 until the
tree 4 has been
completely cut at which time the tree held by the gripping arms 50 may be air-
lifted to a suitable
collection area.
As illustrated in Figure 2, the carriage 102 maybe located at the second end
of the
slide bar 90. In this orientation, the gripping arms 50 will extend vertically
downward from the
cutting apparatus 10 so as to enable the gripping arms 50 to grasp and lift an
object lying on a
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ground, such as for example, a log or other object. It will be appreciated
that this orientation will
also be useful for gripping and cutting snags at a low angle of inclination.
As illustrated in Figures 5 and 6, the carriage 102 may be moved between the
first
and second ends 92 and 94 of the slide bar 90 by first resting the cutting
apparatus 10 on the
ground. The helicopter 6 may then create slack in the line 8 so as to permit
the slide bar 90 to
come to a resting position. The helicopter 6 may then drag the carriage 102 in
the direction of the
end of the slid bar 90 that is desired for the required orientation of the
cutting apparatus 10.
Thereafter the helicopter 6 may lift the cutting apparatus 10 from the
selected first or second end
92 or 94 of the slide bar 90 so as to lift the cutting apparatus in the
desired orientation. As
illustrated in Figure 5, the carriage is moved from the first end 92 to the
second end 94 of the slide
bar in a direction indicated at C. It will be appreciated that the carriage
may also be moved in a
reverse direction.
It will also be appreciated that the cutting apparatus 10 will typically be
used to
grasp a tree 4 to be cut with the carriage 102 at the second end 94. After the
gripping arms 50
have secured the cutting apparatus 10 to the tree 4, the helicopter 6
mayprovide some slack in the
line 8 and slidably move the carriage 102 to the first end 94 of the slide bar
90 prior to cutting the
tree with the chain saw 70 in a similar to the manner described above and
illustrated in Figures 5
and 6. The helicopter 6 may thereafter reapply an upward lifting force through
the line 8 to the
second end of the carriage 102. The carriage 1021ifts up on the second end 94
of the slide bar 90
which is then pivoted about the pivot 100 until the first end 92 of the slide
bar 90 rest on the side
brace 36. The helicopter may thereafter apply a torque to the cutting
apparatus 10 and the tree 4 a
direction indicated at D. It will be appreciated that this will permit the
helicopter operator to
control the direction in which the tree 4 will fall by positioning the cutting
apparatus 10 on the
opposite side from the direction of fall and applying a torque to the tree
while cutting it with the
chain saw 70.
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The hydraulic system of the present apparatus may include a quick release mode
of
operation whereby the activation of a single control by a user will rapidly
and concurrently reduce
the throttle of the chain saw, retract the chain saw from a cutting motion and
release any object
held in the gripping arms. The quick release mode may be achieved by providing
a diversion
valve to each hydraulic cylinder to divert the hydraulic fluid back to the
hydraulic tank 42 and
interrupt the pressure to the hydraulic cylinders. In addition a compressed
air return reservoir (not
shown) for each hydraulic cylinder may be utilized to rapidly return the
hydraulic cylinders to their
resting locations. They hydraulic lines for one or more of the hydraulic
cylinders may also include
a flow monitoring valve or a pressure control valve which is operable to
divert a portion of the
hydraulic fluid flow to a hydraulic cylinder when a predetermined resistance
to movement of that
cylinder is encountered. This will prevent the gripping arms 50 from gripping
too tightly on a tree
or other object and will prevent too large of a feed rate from being applied
to the chain saw which
may result in the chain saw stalling.
As will be apparent to those skilled in the art in the light of the foregoing
disclosure, many alterations and modifications are possible in the practice of
this invention
without departing from the spirit or scope thereof. Accordingly, the scope
ofthe invention is to be
construed in accordance with the substance defined by the following claims.
