Note: Descriptions are shown in the official language in which they were submitted.
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HELICOPTER SINGLE STEM HARVESTING SYSTEM
BACKGROUND OF THE INVENTION
This invention relates to systems for logging using
helicopters and, in particular, selectively logging relatively
large trees directly from the stump by helicopter.
The most common method of logging is probably clear-cut
logging where a large area of forest is completely cleared.
Commercially useful trees are removed, while remaining debris
is usually burned. However, there are situations where clear-
cut logging is not feasible or desirable. For one thing, it
has become increasingly unpopular among environmental groups.
Clear cuts can have a high visual impact to the public and,
unless carefully controlled, can lead to a loss of adjacent
trees due to a windfall. The selective harvesting by felling
individual standing trees is another conventionally used
method. In selective harvesting, trees are individually
felled and de-branched. Felling trees often causes damage to
the felled tree trunk (log) and invariably causes damage to
undergrowth. Removal of logs is often difficult and expen-
sive, particularly in rugged terrain. Helicopter logging,
that is logging where the trees are removed initially by
helicopter, is a well-known technique. For example, one
system of lifting and transporting felled timber is disclosed
in my earlier United States Patent No. 4,152,019.
Soviet Union Patent 1074432 discloses a system of
logging by blasting tree roots loose by explosives while
helicopter pulls them upwards.
Another procedure is disclosed in Russian Patent
2,014,776. This procedure is used when clearing paths through
forests for roads or the like. Air flow from the helicopter
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rotor is directed onto the crowns of the trees so that they
are blown downwards toward a clearing.
Published Russian Patent Application No. RU 2,095,698
discloses a logging method in which a trunk of a tree is cut
from two sides, leaving a connecting portion between the saw
cuts. Wedges are driven into the saw cuts and vertical
members of a securing device are mounted around the tree in
such a manner that the connecting portion can later be sawed
away. The connecting portion is eventually sawn away, leaving
the cut tree standing on the stump (secured in place by the
securing device). The cut tree can later be lifted clear by
means of a helicopter. This method requires the acquisition
of a number of securing devices, if a larger number of trees
are prepared at the same time for being harvested before the
arrival of the helicopter. Every additional mechanical device
has to be stocked, maintained, transported to the site,
installed and removed. Such 'manipulation complicates the
process and increases the overall cost of the logging.
Further, according to this method, the ground crew must visit
the tree twice, once to saw the tree part way through, and
then again later to saw through the connecting portion. As
terrain is often difficult, requiring the ground crew to visit
the tree twice is time-consuming and expensive.
Despite these earlier methods, there remains a need for
an improved method for selectively logging relatively large
trees without requiring, for example, the construction of
environmentally damaging roads through the forest.
It is therefore an object of the invention to provide
an improved system for logging which permits selected,
relatively large trees to be initially removed by helicopter
without adversely affecting adjacent growth.
It is also an object of the invention to provide an
improved system for helicopter logging which is economical to
utilize for many different situations.
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SLJNINIARY OF THE INVENTION
There is provided, according to one aspect of the
invention, a method of logging a tree having a trunk with a
top and bottom that allows a tree trunk to be harvested
without felling. According to the method, a selected tree is
first topped. The method further comprises the steps of
cutting the tree part way through the trunk by two generally
horizontal opposite cuts near the bottom thereof, the cuts
being separated by a remaining connecting portion (holding
wood) connecting an upper portion of the trunk above the cuts
to a lower portion of the trunk below the cuts. The first cut
is preferably made against the lean of the tree extending into
the trunk approximately two-third the diameter of the trunk.
The second cut is then made preferably generally in the same
horizontal plane as the first cut, but stopping short of the
first cut so as to leave a suitable selected thickness of
holding wood. Auxiliary support conveniently is provided by
support wedges driven into both cuts to stabilize the trunk,
so that the wedges and the holding wood maintain the trunk
stable and upright until it is harvested.
When the log is ready tb be harvested, a helicopter
provided with a suitable grapple suspended underneath the
helicopter manoeuvres into position over the tree trunk so
that the grapple can engage and grip the top of the trunk.
The helicopter moves away from the tree, thereby applying a ,
generally horizontal force to the top of the tree, forcing the
trunk to pivot about the connecting portion (holding wood) of
the trunk between the saw cuts and ultimately breaking the
holding wood and allowing the upper portion of the trunk to be
carried away by helicopter. It may be necessary to apply the
horizontal pivoting force alternately in both directions
perpendicular to the cut edges until the holding wood breaks.
A ribbon or other marking may be of f fixed to the top of the
topped tree trunk to indicate (to the helicopter pilot) the
direction of the cuts made into the tree trunk, facilitating
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correct orientation of the helicopter movement required to
break off the log from the stump.
The selection of the thickness of the holding wood will
depend upon a number of factors, including the length and
diameter of the tree trunk to be harvested, the species of
tree, prevailing conditions (especially susceptibility to
strong winds), and possibly other factors, and is best
empirically determined.
There is provided, according to a further aspect of the
invention, a helicopter logging apparatus suitable to
implement the foregoing method which includes a helicopter
having a pilot's seating position, a center of gravity, a
first attachment point below the helicopter to one side of the
pilot's seating position and a second attachment point below
the center of gravity. A first cable is connected to the
first attachment point and a second cable is connected to the
second attachment point. There is a device for lengthening
the first cable so that its length may vary as between guiding
mode and log suspension mode. The helicopter carries a
grapple for gripping and carrying the top of a topped standing
tree trunk. The grapple in operation accordingly is oriented
so that it grips the trunk while the trunk is vertical, in
contradistinction to the orientation of grapples used to grip
felled trees. A grapple has a body with a top, a bottom and
a side. There are a first and a second attachment means on
the top of the body of the grapple spaced apart from each
other. The first cable is connected to the first attachment
means of the grapple and the second cable is connected to the
second attachment means of the grapple. When the grapple is
not carrying a log (guiding mode), the grapple is situated
underneath the nose of the helicopter for better visibility,
suspended by the first cable. Later, while when the grapple
is carrying a log (log suspension~mode), the first cable is
lengthened by the lengthening device so that the grapple and
the log it carries are positioned directly underneath the
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center of gravity of the helicopter, suspended by the second
cable.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
Fig. 1 is a side view of a helicopter approaching a
topped tree with a logging tool, according to an embodiment of
the invention, while employing a method of logging the tree
according to the invention;
Fig. 2 is a view similar to Fig. 1, showing the
helicopter and tree after the.tool on the helicopter has
engaged a cable secured to the tree;
Fig. 3 is an enlarged, side elevation view of the tool
of Fig. 1 and 2;
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Fig. 4 is a view similar to Fig. 3, showing the position of the tool while
carrying the trunk
of the tree;
Fig. 5 is in a top, side isometric view of a jig apparatus for cutting the
trunk of the tree,
S according to an embodiment of the invention;
Fig. 6 is a side elevation of a guide bar thereof;
Fig. 7 is an end view thereof;
Fig. 8 is a top plan of a chain saw bar;
Fig. 9 is an enlarged view of the cables and tool oriented as when carrying a
load;
Fig. 10 is a front view of a grapple according to another embodiment of the
inventions;
Fig. 11 is a side elevation thereof;
Fig. 12 is a top plan view thereof;
Fig. 13 is a fragmentary side view of a helicopter, attached sled and cables
for carrying the
grapple of Fig. 10;
Fig. 14 is a top plan of the sled;
Fig. 15 is a fragmentary side view of the nose of the helicopter; and
Fig. 16 is a side view of a tool and cables, similar to Fig. 9 using a tool
according to a further
embodiment of the invention.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Refernng to the drawings, and first to Fig. 1, these illustrate a method of
logging a tree 10
using a helicopter 12 provided with a tool or grapple 14 suspended from the
helicopter by
$ a pair of cables 16 and 18. The tool 14 is suspended below a first
attachment point 20 which
is below the helicopter and to one side of the pilot's seating position 22.
Thus the tool 14 can
be viewed easily by the helicopter pilot. The second cable 18 is connected to
the helicopter
at a second attachment point 24 which is below the center of gravity 26 of the
helicopter and
its rotor shaft 28.
The tool or grapple 14 is shown in better detail in Fig. 3 and 4. The tool has
a body 30 with
a top 32, a bottom 34 and opposite sides 36 and 38. These parts are identified
with reference
to the position of the tool shown in Fig. 1 and 3. The body has first means
thereon for
connecting the body to lifting device, in this case the helicopter and cables
16 and 18. In this
1$ example the first means includes a machined metal stub 40 which is screwed
into the body
and a cable connector 44 connected to the body by a swivel 46. Cable 16 is
connected to
stub 40 and cable 18 is connected to the body by cable connector 44. Tubing
19, of PVC in
this example, extends over cable 18 as seen in Fig. 9. The cable connector and
stub are
adjacent the top 32 of the body and spaced-apart from each other. There is a
heavy duty
spring 41 adjacent stub 40 as seen in Fig. 9. A pipe 43 of aluminum and 8'
long in this
example, extends over cable 16 adjacent the spring. Tubing 19 and pipe 43
inhibit winding
up of the cables.
The body also has an elongated guide 48, having a tapered proportion $0 which
decreases
2$ in cross sectional extent outwardly from the body. The guide 48 is
connected to the body
by a hinge $2 at the bottom 34 of the body.
There is a flexible extension $1 to the guide. In this example the extension
is a flexible
radiator hose filled with sand and plugged at the bottom end.
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There is second means on the body on one side of the guide, namely side 36 of
the body, for
engaging an object. In this case the second means includes a hook 60 and a
safety catch 62
which is hingedly connected to the body and prevents slings and the like from
becoming
disengaged after they are received on the hook. This is a standard Breeze
Eastern Hook
employing an electro- mechanical release device, including electrical actuator
42, which
allows slings and like to be released from the hook when desired. This is
conventional and,
accordingly, is not described in more detail.
Cable 18 is a fixed length cable extending between attachment point 24 on the
helicopter and
cable connector 44. However cable 16 is connected at a point 70 to a
tensioning line 72
normally wound on tool balancer 74. The tool balancer is a cylindrical housing
with an
attachment point on top and a spring loaded drum inside. This tool balancer is
conventional
and accordingly is not described in more detail. When a load is applied to the
hook, the
tensioning line is pulled from the tool balancer. When the load is released,
the tool balancer
is capable of carrying the weight of tool 14 and rewinds the tension line. The
tension line
is shown pulled out of the tool balancer in Fig. 2 and is wound on the tool
balancer in Fig.
1. In an alternative embodiment the tool balancer is replaced by a length of
industrial grade
bungee cord.
Referring to Fig. 1 and 2, the tree 10 has a trunk 80 with a top 82 and a
bottom 84. The tree
in this example has been topped, as may be seen in the drawings, and has been
partially cut
through by two cuts 86 and 88 on opposite sides of the trunk near the bottom
thereof.
Refernng to Fig. 5, this shows a jig apparatus 90 used for making one of the
cuts in the trunk
of the tree. The jig apparatus includes two guide bars 92 and 94 which, in
this example, are
channels which open outwards away from tree trunk 80, forming a guide track 96
extending
longitudinally along the inside of each guide bar. This guide track receives a
double roller
truck 98 connected to a chain saw mount 100 on the top of each of the guide
bars. Each
mount includes a plate 101 which has an L-shaped shaft 99 with the truck 98
mounted on
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the bottom as seen in Fig. 7. There is a toggle 103 on the
top of the shaft and a pair of spaced-apart washers 113 and
115 with a coil spring 111 therebetween. The toggles are
rotated to the position for guide bar 92 to install the chain
saw bar, washer 113, spring 111 and washer 115 in that order.
The toggle is then rotated to the position for guide bar 94.
There is a means for connecting the guide bars to the
trunk Of the tree in horizontal, parallel positions on
opposite sides of the trunk as seen Fig. 5. This means
includes a plate 120 connected to guide bar 92 and a similar
plate 122 connected to guide bar 94. Each plate has a
plurality of inwardly directed spikes 124 which can be
hammered into the tree trunk, thus attaining the position of
each guide bar shown in Fig. 5. Each plate has a series of
slots 130 along top 132 thereof which can receive one of the
connecting bars 140 and 142. There is also a keeper bar 160
with a series of slots 162 to similar to the slots 130 in the
plates 120 and 122. The slots in this bar are fitted over the
ends of connecting bars 140 and 142 extending outwardly from
plate 120. Each of the connecting bars has a pin 170 at one
end and a removable pin 171 at the opposite end. The pins 171
.are secured to keeper bar 160 by a wire 173. There is a
single aperture 172 at one end of each bar and a series of
apertures 174 at the opposite end. One pin 170 is fitted
fixedly through each aperture 172 and another pin is 171 is
removably fitted through a selected aperture 174 which is
closest to the keeper bar 160, after the keeper bar is held
adjacent the trunk of the tree. A wedge 180 is driven between
the keeper bar and guide bar 92 to keep the jig apparatus
tight against the tree.
Once the tree has been topped, an initial cut is made
in the tree approximately two-thirds the way through the
trunk. This may be, for example, cut 88 shown in Fig. 1 and
2. This cut is made against the lean of the tree. Wedges 194
are inserted and the saw bar is removed. The jig apparatus is
used to position and dimension the second cut 86 such as to
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leave a connecting portion (holding wood) 190 between the
first cut and the second cut which is capable of supporting
the tree trunk 80 until the helicopter arrives, at least in
conjunction with a series of wedges 192 and 194 which are
driven into the cuts to support the tree on each side of the
connecting portion 190. The wedges are taped in with high
visibility tape to make them conspicuous and keep them in
place if the tree rocks in the wind.
After the first cut 88 is made, the connecting bar 140,
with plate 122 in place, is positioned in the cut 88 snug up
against the connecting portion 190. The spikes 124 are driven
into the tree trunk. The connecting bar 142 is then posi-
. tinned between pairs of slots 130 outwardly from the tree
trunk to stabilize the equipment. The guide bar 92 is now
fitted over the connecting bars and spikes 124 of its plate
120 are pounded into the tree. The keeper bar 160 is fitted
over the ends of the connecting bars projecting from plate 120
and the pins 170 are fitted through the apertures in the
connecting bars. Finally one or more wedges 180 are driven
between the keeper bar and bar 92 to tighten the assembly
against the tree.
After the assembly is properly positioned, the saw bar
107 of a chain saw can be mounted on the tops of plates 101
and the chain saw pushed, while running, along the guide bars
towards the tree. There are two stop mechanisms on each guide
bar. Stop mechanism 199 is on the end distal the tree and
there is an adjustable stop mechanism 200 on each guide bar,
, which contacts truck 98 to prevent the roller trucks moving
further towards the tree and, accordingly, keeps the cuts 86
and 88 from merging. Each stop mechanism 200 is moveable by
an Allen screw adjustment. The amount of connecting portion
190 left is calculated depending upon the species of tree, its
moisture content, diameter and other such factors as the
amount of lean of the tree. Typically it is between 1/411 and
211. As discussed above, wedges 192 and of 194 are driven
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into the cuts 86 and 88 to support the trunk of thee tree
until the helicopter arrives.
After the tree is topped, the logger attaches a cable
201 to the top of the tree, leaving a loop 202 projecting from
the top 82 of the trunk. A significant length of cable beyond
the loop is wound around the trunk of the tree and secured
thereto as seen in Fig. 1. The loop (or choke) 202 is located
on the low side of a leaning tree.
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When the helicopter arnves, as seen in Fig. 1, the guide extends vertically
downwards as
shown. Spring 41, shown in Fig. 9, is straight when the tool is oriented as in
Fig. 1. After
this is accomplished, the loop 202 is received by hook 60. The guide 48 allows
the pilot to
determine his height and displacement from the loop 202. The device bumps the
loop from
the outside and serves to keep the hook 60 oriented correctly. As the
helicopter is lowered,
the hook engages the loop. The pilot then moves the helicopter upwards, thus
pulling cable
201 away from the tree trunk, tightening the cable and reducing the size of
the loop as seen
in Fig. 2. At the same time, the load on the hook rotates the hook to the
position shown in
Fig. 2, and pulls tension line 72 from tool balancer 74. Accordingly the tool
is then
suspended below the attachment point 24 and center of gravity 26 of the
helicopter by cable
18 connected to cable connector 44. This rotation of the tool causes the guide
48 to rotate
relative to the tool about hinge 52, as shown in Fig. 2, such that the guide
continues its
vertical orientation pointing away from the tool. This inhibits the tool from
spinning. Spring
41 is bent to the shape shown in Fig. 9 when the tool is in the position of
Fig. 2.
The pilot then flies the helicopter away from vertical alignment with the tree
trunk and
releasing the wedges 192 and 194 as seen in Fig. 2. The leverage achieved by
the distance
between the attachment point for cable 201 and connecting portion 190, namely
the length
of the tree trunk, provides sufficient force to break the connecting portion,
assuming it has
been sized correctly. Once this is broken, the helicopter can lift the tree
trunk vertically
upwards and carry it to a remote site for further transport. When the load is
released, the
spring 41 and tool balancer 74 re-orient the tool to the position of Fig. 1.
Figure 16 shows a variation of tool 14 which is generally similar. Like parts
have like
numbers with the addition of ".1". The tool is inverted compared with the
previous
embodiment and there is no guide 48. Line 16.1 is used as a guide instead. The
pilot bumps
loop 202.1 with line 16.1 and then lifts up the line, dragging it along the
loop, until hook
60.1 engages the loop. This embodiment uses a bungee cord instead of a tool
balancer and
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this stretches after the helicopter rises, causing the load to shift aft so it
is carned by line
18.1.
Fig. 10 - 12 show a grapple 300 which replaces the tool or grapple 14 shown in
Fig. 1 - 4.
Grapple 300 has a plate-like support member 302 which is vertically elongated
from top 304
to bottom 306 thereof. There is a first attachment means in the form of an eye
308 connected
to the top thereof and a second attachment means in the form of an eye 310
connected to a
vertical fin 311 extending centrally along back 312 of the support member. The
eye 310 in
this example is just above the mid point of the support member between top 304
and bottom
306 thereof.
As seen best in Fig. 10, the support member has two vertical sides 330 and
332. Two wings
334 and 336 are connected to the sides of the support member and extend
outwardly
therefrom and diverge away from each other as may be seen best in Fig. 12.
Thus a tree
receiving recess 338 is formed between the wings and the surface 316. The
wings are also
plate-like and are vertically elongated as seen best in Fig. 10. They extend
from near the top
to near the bottom of the support member. Grapple arms 340 and 342 are
pivotally
connected to the wings 334 and 335 respectively by hinges 350 and 352. The
arms include
a spline 360, a generally triangular member 362 and reinforcing ribs 364 as
seen best in Fig.
11.
There is a fluid actuator, in this case, a hydraulic cylinder 370, mounted on
the grapple and
connected to back ends 372 and 374 of the grapple arms by pivot connections
376 and 378.
The cylinder passes through an aperture 380 in the fin 311. The barrel of the
cylinder is
connected to one of the arms, in this case arm 340, by a rod 390. The other
arm is connected
to the piston of the cylinder by a rod 392. A hydraulic line 394 connects the
cylinder to a
hydraulic pump within the helicopter.
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Cables 16.2 and 18.2 are connected to the eyes 308 and
310 and are connected to a helicopter in a manner similar to
cables 16 and 18 shown in Fig. 1.
There are a pair of flexible elongated members or wands
400 and 402 which are connected to outer ends 404 and 406 of
the grapple arms as seen best in Fig. 12. The wands in this
example are glass fibre reinforced polymer rods which are 1/2"
in diameter adjacent the grapple and which taper outwards,
although alternative materials could be substituted. As may
be seen, the elongated members diverge away from each other on
opposite sides of the recess 338. In this example there is a
7' gap between the outer ends of the wands. They effectively
widen the grapple to this extent to assist the pilot in
engaging the tree. When either wand touches the tree the
grapple is turned toward the top of the tree. The wands are
flexible so they will bend and flex without breaking.
Referring to Fig. 13 - 15, helicopter 400 has a hard
point 402 which has a universal joint 404 mounted thereon,
just below the nose 403. A rod 406 is connected to the
universal joint such that the rod can pivot. A sled 410, with
a square tubing frame in this example, is mounted on the rod.
The sled has rollers (not shown) on front 412 thereof, a top
roller close to the front and a bottom roller spaced-apart
rearwardly therefrom. These rollers engage the rod 406. A
hydraulic power pack 420 is mounted on the sled and hydraulic
line 422 connects the power pack to the grapple. The rollers
allow the sled to roll off rod 406 if main hook 430 is
released. Effectively this allows a single point release on
a system using two lines. Thus the system can be adapted for
all helicopters without the need for a costly interface and
certification thereof. The power pack 420 is run from the
helicopter electrical system.
This example uses a length of industrial grade bungee
cord 440 as means for lengthening the cable 16.2 alter the
tree is coupled to the grapple.
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In use, the pilot flies the helicopter to a site that
had been prepared in a manner similar to the manlier described
for the previous embodiment. The top of a tree should be
clearly marked
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with a ribbon indicating the direction of the cut made on the trunk below and
the prevailing
wind. The pilot approaches the tree with the wands 400 and 402 on opposite
sides of the
stem. As the wands touch the stem, they bend and turn the grapple in the
direction of the
open arms 340 and 342. The pilot moves the grapple towards the tree until the
stem is
S against the surface 316 of the support member, within the recess 338 and
against the
projections 320. The pilot then activates the cylinder 370 by a switch which
operates the
hydraulic pump on the sled. The switch is preferably located on the collective
control of the
helicopter. It closes the grapple arms and locks the grapple to the tree.
From this point, the procedure is the same as before. The pilot breaks the
stem by pulling
the stem horizontally in the direction indicated by the ribbon placement.
After the stem is
broken, the load is transferred from cable 16.2 to cable 18.2 which is below
the center of
gravity of the helicopter. Because the grapple is attached to the cable 18.2
by eye 310, which
is spaced-apart from the top of the grapple, the center of gravity of the log
will be aft and
1 S below the grapple. Thus it will release from the grapple arms downwardly
when they are
opened at the desired location for releasing the log.
It will be appreciated by someone skilled in the art that many of the details
provided above
are by way of example only and are not intended to limit the scope of the
invention which
is to be interpreted with reference to the following claims.
