Note: Descriptions are shown in the official language in which they were submitted.
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TITLE OF THE INVENTION
Tree harvester provided with a rotatable worktable
FIELD OF THE INVENTION
The present invention relates to tree harvesters. More
specifically, the present invention is concerned with a tree harvester
provided with a boom and a rotatable worktable assembly.
BACKGROUND OF THE INVENTION
There are two commonly known types of tree harvesters:
single-grip harvesters and double-grip harvesters.
Single-grip harvesters have all their tree processing
devices mounted on a single articulated boom. Such an harvester is
disclosed in the United States Patent N 4,416,311, entitled "Tree
Harvester", issued on November 22, 1983 and naming Gemmell-Murdoch
as inventor. Gemmell-Murdoch's harvester has a felling assembly and a
delimbing assembly mounted on the same boom.
A drawback of Gemmell-Murdoch's harvester is that the
boom is not available to process another tree or even to be repositioned to
process another tree after the felling, since the boom is also used to delimb
the tree. Furthermore, since the delimbing assembly is positioned on the
boom, single-grip harvester's boom are usually heavy end bulky and can
cause damages to the trees. Single-grip harvesters are therefore not
particularly efficient.
On the other hand, double-grip harvesters have only
their tree felling device mounted to the boom. The other tree processing
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devices are mounted on a worktable. An example of a double-grip
harvester can be found in United States Patent N 3,805,859, entitled
"Delimbing Assembly for a Tree Harvester" and issued to Kessler et al. on
April 23, 1974. Kessler's tree harvesting vehicle comprises a tree
delimbing assembly mounted in front of the vehicle and an articulated
boom that includes a tree felling assembly. After felling a tree, the boom
brings the tree to the delimbing assembly. During the delimbing process,
the boom can fell a second tree, therefore increasing the overall efficiency
of the harvesting vehicle.
A drawback of Kessler's harvester is that the delimbing
assembly is fixedly mounted to the vehicle. Indeed, the processed tree
sometimes prevents free movement of the boom. Another drawback of
Kessler's harvester is that it cannot accumulate trees after the delimbing
process. The operation of the boom is therefore often stopped, since the
boom has to remove the delimbed tree from the delimbing assembly.
A solution has been proposed to this problem by Hahn in
United States Patent N 4,382,457, issued on May 10, 1983 and entitled
"Tree Harvester". Hanh proposes a tree harvester provided with a bed, to
delimb and cut a tree to a desired length, and a kickout table to receive
and stack the severed logs. While Hahn's machine shows improvements
over Kessler's, it presents the major drawback of being huge. This is a
major drawback since the bigger the harvester and the greater the chance
to damage the trees or the environment.
Furthermore, Hahn's machine still has the same problem as Kessler's
harvester regarding the fact that, the bed being fixedly mounted to the
movable frame, it can sometimes prevent free motion of the boom.
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OBJECTS OF THE INVENTION
An object of the present invention is therefore to provide
an improved tree harvester free of the above mentioned drawbacks.
Another object of the invention is to provide a tree
harvester that is configured to perform simultaneously different tree
harvesting operations.
SUMMARY OF THE INVENTION
More specifically, in accordance with the present
invention, there is provided a tree harvester comprising:
a movable frame;
a worktable assembly so mounted to the movable frame
as to rotate about a first rotational axis; the worktable assembly being
provided with at least one worktable mounted tree processing device; and
an upper frame so mounted to the movable frame as to
rotate about a second rotational axis; the upper frame being provided with
a boom having proximate and distal ends; the proximate end being
mounted to the upper frame; the distal end being provided with at least one
boom mounted tree processing device.
Other objects, advantages and features of the present
invention will become more apparent upon reading of the following non
restrictive description of preferred embodiments thereof, given by way of
example only with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the appended drawings:
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Figure 1 is a front elevational view showing a tree
harvester according to a first embodiment of the present invention; the
rotatable worktable assembly being shown in front view while the upper
frame being shown in side view;
Figure 2 is a side elevational view of the tree harvester of
Figure 1;
Figure 3 is a front elevational view of the tree harvester
of Figure 1 illustrating the operation of the feller head and of worktable
assembly;
Figure 4 is a front elevational view of the tree harvester
of Figure 1, illustrating the boom feeding a tree to the worktable assembly;
Figure 5 is a front elevational view of the tree harvester
of Figure 1, illustrating the grapple grabbing a tree after the delimbing
process;
Figure 6 is a top plan view of the tree harvester of Figure
1, illustrating the multi-processing capability of the tree harvester;
Figure 7 is top plan view of the tree harvester of Figure
1, illustrating the operation of the tree harvester; and
Figure 8 is a side elevational view of a second
embodiment of tree harvester according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to Figures 1 to 3 of the appended drawings, a
tree harvester 10, according to a first embodiment of the present invention,
will be described.
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The tree harvester 10 comprises a movable frame 12, a
rotatable worktable assembly 14 and an rotatable upper frame 16.
The movable frame 12 is similar to standard excavator
frames and is therefore well known in the art. The movable frame 12 is
5 power driven and includes endless tracks 18 and 20. The movable frame
12 further includes a turntable 22 centered about a rotational axis 24. Of
course, wheels can be used instead of endless tracks.
The turntable 22 includes a fixed portion (not shown)
fixedly mounted to the movable frame and a rotatable portion (not shown)
rotatably mounted to the fixed portion.
The worktable assembly 14 includes a spacer 26, a
worktable 28, a tree delimbing mechanism 30, a tree cutting mechanism 32
and a log stacker 33. The worktable assembly 14 is mounted to the
rotatable portion of the turntable 22 of the movable frame 12 via the spacer
26. The spacer 26 is fixedly mounted to rotatable portion of the turntable
22. A power driving mechanism (not shown) drives the rotation of the
rotatable portion the turntable 22 and therefore of the spacer 26 about the
rotational axis 24.
The worktable 28 is mounted to the spacer 26 and
consists of a longitudinal frame to which the other elements of the
worktable assembly 14 are mounted. The worktable 28 includes a
longitudinal axis 34 (Figure 2) and two longitudinal ends 36 and 38. The
worktable 28 is so configured and sized as to support the tree delimbing
mechanism 30, the tree cutting mechanism 32 and the log stacker 33 and
as to support horizontally a felled tree.
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The tree delimbing mechanism 30 includes two knifes 40
and 42, a switch 43, two pull rolls 44 and 46 and an actuator mechanism
48. The pull rolls 44 and 46 are provided with projecting teeth to engage
the wood of a tree. The pull rolls 44 and 46 are mounted to the worktable
28 at the longitudinal end 38 thereof. The actuator mechanism 48 is
provided to control the relative distance between the two rolls 44 and 46 to
enable the processing of trees of different sizes. The two rolls 44 and 46
are equally spaced apart from the longitudinal axis 34. The switch 43 is so
positioned as to be pushed by a tree to trigger the actuator mechanism 48.
The knives 40 and 42 are mounted to a support 50 which
is pivotally mounted to the worktable 28 via cylinder 52. The support 50
contains actuators (not shown) to control the pivoting of the knives 40 and
42 respectively about pivot pins 54 and 56 (Figure 1). The knives 40 and
42 are symmetrically disposed about the longitudinal axis 34.
The tree cutting mechanism 32 includes a telescopic
floor 58, a tree grabber 59, an engaging ring 60, a saw (not shown)
mounted in a saw housing 62 and a mechanical stop 64. The telescopic
floor 58 has two longitudinal ends 66 and 68, and is formed by tubes, such
as for example, tube 70, in which is telescopically mounted a rod, for
example rod 72. The tree grabber 59 includes three pairs of half-moon
shaped claws 76, each secured on a pivot structure 78 (Figure 3) allowing
the claws to pivot between opened (not shown) and closed (see Figure 3)
positions. The pivot structure 78 is mounted to the worktable 28 via a
hydraulic arm 80. The telescopic floor 58 and the tree grabber 59 are
secured on the worktable 28 and are aligned with the longitudinal axis 34.
The mechanical stop 64 is mounted to the telescopic
floor 58, at the longitudinal ends 68, via a hinge mechanism 81 that allows
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the mechanical stop to be pivoted between an operating position (shown,
for example, in Figure 2) and a non-operating position (shown, for
example, in Figure 5). Since the telescopic floor 58 can move longitudinally
along axis 34, the mechanical stop 64 can be positioned at different
distances from the saw.
The engaging ring 60 and the saw housing 62 are
mounted to the worktable 28, near the longitudinal end 38. The saw
housing 62 is located behind the rolls 44 and 46, while the engaging ring
60 is located between the saw housing 62 and the rolls 44 and 46. The
engaging ring 60 is generally centered about the longitudinal axis 34 and is
used to align a tree with the longitudinal axis 34. As mentioned
hereinabove, the saw housing 62 contains a chain saw (not shown) so
mounted on a pivoting support (not shown) as to enable the cutting of a
tree trunk going through the ring 60.
As can be better seen from Figure 3, the log stacker 33
includes a rack 82, configured and sized to support a plurality of wood logs
84, and ejecting arms 86. The ejecting arms 86 are so mounted to the
worktable 28 as to slide laterally relatively to the longitudinal axis 34 (see
arrow 87), to therefore laterally move a cut log 84 from the worktable 28 to
the rack 82 when the claws 76 are in their opened positions (not shown).
Returning to Figure 1, the worktable assembly 14 is also
provided with a tree conveyor 130 to feed trees to the tree delimbing
mechanism 30. The conveyor 130 includes a strap 132, mounted on
pulleys 134 (only one shown) and provided with teeth 136. A tree trunk
placed between teeth 136 can be brought near the longitudinal axis 34 by
the rotation of the pulleys 134.
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The conveyor 130 therefore allows the user to cut trees
faster than the worktable mounted tree processing devices may process
them. It is to be noted that the conveyor 130 could be removed from the
tree harvester 10 without departing from the spirit and nature of the present
invention.
As can be better seen in Figure 3, the upper frame 16
includes a crane room 90, a turntable 92, a counterweight 94, a boom
support 96 and a conventional articulated boom 98. The upper frame 16 is
rotatably mounted to the spacer 26 via the turntable 92, which is fixedly
mounted to the upper frame 16. The boom support 96 is secured to the
crane room 90.
The articulated boom 98 includes a jib 100, an arm 102
and a conventional feller head 104. The jib 100 includes a proximate end
pivotally mounted to the boom support 96 via pivot pin 108. The pivotal
movements of the jib 100 relative to the upper frame 16 are actuated by a
hydraulic actuator 110, mounted to the boom support 96 and to the jib 100
via respective pivots pins 112 and 114.
The arm 102 includes a proximate end pivotally mounted
to the distal end of the jib 100 via a pivot pin 116. The pivotal movements
of the arm 102 relative to the jib 100 are actuated by a hydraulic actuator
118, mounted to the jib 100 and to the arm 102 via respective pivots pins
120 and 122.
The feller head 104 is so mounted to the distal end of the
arm 102, via an attachment 124, as to be able to pivot and rotate freely in
all directions. The feller head 104 is equipped with a grapple 126 and a
retractable cutter (not shown) mounted in a protecting box 128. For space
saving the cutter is preferably a chain saw.
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Finally, it is to be noted that the elements may be
secured to one another by welding or other fastening means.
A control station (not shown), advantageously located in
the crane room of the upper frame 16, commands and synchronizes the
operation of the tree processing devices of the worktable 28 and of the
feller head 104.
The control station advantageously includes a controller
circuit (not shown) allowing sequences of operation to be performed
without the constant involvement of the user. Different sensors, such as,
for example switch 43, may be provided to supply data to the controller
circuit. The control station also preferably includes manual override
features allowing the user to manually operate the various tree processing
devices and the turntables 22 and 92.
It is to be noted that the movement of the jib 100, the
arm 102 and of the feller head 104 are actuated via conventional controls
(not shown), located in the crane room 90.
The telescopic floor 58 can be moved manually before
the beginning of the process, to set a predetermined length for the cut logs,
or automatically from the crane room 90, if adequate actuators (not shown)
are provided between the telescopic tubes and rods of the floor 58.
Referring now to Figures 3 to 7, the operation of the tree
harvester 10 will be described. The operation of the tree harvester 10
consists generally of the following steps:
- felling a tree via the feller head 104;
- feeding the tree to the worktable assembly;
- delimbing of the tree;
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- cutting the tree in logs;
- accumulating the logs in the log stacker; and
- emptying the log stacker.
An advantage of the present invention is that the feller
5 head 104 may fell other trees and place them onto the conveyor 130 while
the worktable assembly delimbs the first tree, cuts it in logs and
accumulates the logs.
In Figure 3, the tree harvester 10 is first brought near a
tree 142 to be felled which is grabbed by the grapple 126 of the feller head
10 104. The flexibility of the attachment 124 allows a perfect positioning of
the feller head 104 on the tree 142. The chain saw of the feller head then
gets out of its protecting box 128 to cut the tree 142, while the grapple
firmly maintains the tree 142. The boom 98 brings the tree 142 in a
horizontal orientation (see Figure 4).
The next step is either to bring the trunk of the tree 142
to the engaging ring 60 if the cut tree 142 is to be processed immediately
or onto the conveyor 130 if the cut tree 142 is to be processed later. As
mentioned hereinabove, the operation of the conveyor 130 can be
controlled by the operator or can be triggered by a sensor (not shown) that
detects the absence of a tree in the tree delimbing mechanism 30.
Depending of the size of the conveyor 130, several trees can be stacked,
waiting to be processed by the worktable 28.
If the tree 142 is to be processed immediately, the tree
142 is brought between the two rolls 44 and 46 (see on Figure 4) by the
boom 98 and the weight of the tree 142 triggers the automatic processing
cycle when the tree 142 actuates the switch 43. The knives 40 and 42 are
then closed about the trunk of the tree 142 and the rolls 44 and 46 are
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energized via the actuator mechanism 48 to move the tree 142 toward the
near end 36 of the worktable 28 while the knives 40 and 42 delimbs the
tree 142.
At this point, the tree 142 can either be taken by the
grapple 126 of the feller head 104 to be positioned somewhere on the
ground without further processing, or cut into logs of predetermined length.
It is to be noted that, in the first case, the mechanical
stop 64 is in its non operating position as can be seen in Figure 5 where
the feller head 104 grabs the tree 142 after the delimbing process. It
illustrates one of the advantages of the attachment of the upper frame 16
that can rotate over 360 degrees.
If the tree 142 is to be cut to a predetermined length, the
mechanical stop 64 is in its operating position (see for example Figure 6)
and it stops the longitudinal movement of the tree 142 when the
predetermined length is reached. A log may then be cut with the chain
saw of the tree cutting mechanism 32. It is to be noted that the telescopic
floor 58 is set as to have a predetermined distance between the
mechanical stop 64 and the chain saw. When a log is cut, it is transferred
to the side rack 82 by the ejecting arms 86.
It is to be noted that, as mentioned hereinabove, all the
processing done by the worktable 28 is advantageously automated so that
the operator can turn his attention to the boom 98 to fell another tree.
As shown in Figure 6, the feller arm 104 can also be
used to remove logs 84 from the rack 82 and place them a desired location
on the ground. Figure 6 also illustrates the fact that the boom 98 can be
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used for other tasks, although a tree is being processed by the worktable
28.
Figure 7 shows the tree harvester 10 grabbing a tree
144, while another tree 142 is being delimbed and cut (the mechanical stop
64 is in its operating position) by the worktable 28. Figure 7 further
illustrates another advantage of the fact that both the upper frame 16 and
the worktable assembly 14 may freely and independently rotate about the
rotational axis 24. Indeed, the rotation of the worktable 28 allow the
processed tree to be in a direction clear of standing trees.
The boom 98 can reach trees over a 360 degrees radius
without displacement of the tree harvester 10, therefore decreasing the
displacements of the harvester 10 to help protect the environment by not
damaging the soil or other trees not to be felled. Similarly, since the felled
trees or the logs are placed on the ground via the feller head 104 and not
dumped automatically, the soil is less damaged.
It is to be noted that the control of all the tree processing
devices of the tree harvester 10 have not been described in great details
herein since they are believed to be well known to one skilled in the art.
Turning now to Figure 8 of the appending drawings, a
tree harvester 146 according to a second embodiment of the present
invention is shown. The tree harvester 146 is very similar to the tree
harvester 10 of Figures 1 to 7 and therefore, for concision purposes, only
the differences between these harvesters will be described hereinafter.
The major difference between the tree harvesters 146
and 10 is that the tree harvester 146 comprises two worktables assemblies
148 and 150 between the movable frame 152 and the upper frame 154,
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therefore allowing two trees to be processed simultaneously., while the
feller head 104 fells another tree. It is also to be noted that, since the
worktables are mounted between the movable frame 152 and the upper
frame, 154 the addition of a second worktable does not make the tree
harvester 146, substantially wider than the tree harvester 10.
Another difference between the tree harvesters 10 and
146 is that the tree harvester 146 is not equipped with a conveyor.
It is to be noted that, although the tree harvesters 10 and
146 have been described with a feller head having a single grapple, they
can also be provided with a second grapple 154 to hold another tree.
It is also to be noted that other processing devices could
be attached on the boom or on the worktable without departing from the
spirit and nature of the present invention. The processing devices,
described hereinabove can also take other forms. For example, the tree
cutting mechanism can be equipped with trenching knifes.
The tree harvester according to the present invention
has been described hereinabove with a worktable assembly and an upper
frame rotating about superposed rotational axis. However, one skilled in
the art could design a tree harvester where the worktable assembly and
the upper frame would rotate about distinct rotational axis.
Although the present invention has been described
hereinabove by way of preferred embodiments thereof, it can be modified,
without departing from the spirit and nature of the subject invention as
defined in the appended claims.
