Note: Descriptions are shown in the official language in which they were submitted.
21 ~6~1~
~fRrUANr.sl-l FOR F~O'E'ATING A TRE E-FELLING IMPLEMENT
AND TREE--FELLING IMPLEMENT ~ w
FIELI~ OF THE INVENTION
The present invention relates to a m~hAni sm for
rotating a tree-felling implement rotatably mounted at the
distal end of the boom of a logging vehicle. The r?~h~ni ~m,
the tree-felling implement, the boom and the logging vehicle
10 form a tree-felling machine controlled by an operator and is
to be used on logging ~ites.
BACKGROUND OF TEIE INVENTION
Tree-felling machines are u6ed in r^-h~ni ~ed tree
harvesting for cutting down trees instead of using a manual
chain saw. Each machin0 comprises a logging vehicle with a
boom at the end of which is provided a tree-felling
implement. In use, ta cut down an ad~acent tree, the
20 operator moves the implement towards the base of the tree.
The implement then grab~; a trunk with a set of hydraulically
actuated arms and cuts the trunk at the base with a saw or
a felling shear. The trunk is laid down on the ground or in
a truck afterwards. Some implements can also remove branches
25 from the trunk while still grabbing it, otherwise branches
may be removed by another machine or a manual chain saw, or
even not be removed at all.
Because the boom is generally moving only in the
vertical plane, the implement has to be able to rotate with
30 reference to the boom p]~ane so that it may grab an inclined
or curved tree, or a tree laying on the ground. In
conventional tree-fellir~g machines, the implement is rotated
by means of a single obliaue hydraulic actuator having one
end operatively attached to the boom and another end
35 operatively attached to the implement. With such embodiment,
the implement may not be rotated around its pivot according
21~719
to a wide range angle and this alters greatly the
flexibility of the machine. In some situations, the operator
may have to move the machine around the tree until a
suitable angle is founcl, which may not be always possible
because of the ugually soft soil and all the obstacles in a
logging site. This therefore lowers productivity and addR
unnecessary wear to the machine parts.
SUMMARY OF THE INVENTION
The object of the present invention is to provide
a simple and reliable r-~-bAni 8m for rotating a tree-felling
implement, and a tree-felling implement with such r-~hAn;Rm.
It is further an object of the present invention to provide
a r~hAniRm capable of rotating the implement with reference
to the boom plane in both directions and according to a wide
range angle.
More particularly, the ob~ect of the preRent
invention is to provide a r- -hAni F'n for rotating a tree-
felling implement, the tree-felling implement comprising a
frane rotatably connectable to a distal end of a boom of a
logging vehicle by an~ implement pivot, the mechanism
comprising:
a pinion coaxial with the implement pivot and fixed in
rotation with reference to the distal end of the
boom;
an arc-shaped rack rotatably mounted on the frame of
the implement by a rack pivot in spaced
relationship ~iith the pinion, the rack being in
mesh with the pinion; and
actuating means provided on the frame of the implement
for swaying the rack and thereby rotating the
implement with ref erence to the boom .
It is also an object of the present invention to
provide a tree-felling implement comprising:
a frame;
214~71 9
-
an implement pivot for rotatably connecting the frame
to a distal end of a ~oom of a logging vehicle;
a pinion coaxial ~ith the Lmplement pivot and fixed in
rotation with reference to tlhe distal end of the
boom;
an arc-shaped rac3~ rotatably mounted on the frame of
the implement ~y a rack pivot in spaced
relationship with the pinion, the rack being in
mesh with the pinion; and
actuating means provided on the frame of the implement
for swaying the rack and thereby rotating the
implement with reference to the boom.
A non restrlctive description of a preferred
: ` lo~ nt Will now be given with reference to the ~rr.ond~rl
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of a logging vehicle with
the tree-felling implement according to the
present invention.
FIG. 2 i5 a rear view of the implement, showing the
implement in 3 central position with reference to
the boom axis.
FIG. 3 is a top view of the implement in FIG. 2, shown
without the pinion and the hydraulic actuators of
the rack.
FIG. 4 is an elevational view of the implement shown in
FIG. 2, showing the implement in an example of an
extreme angulctr position.
~ 21~6719
DESCRIPTION OF A PREFERRED EMBODIMENT
Reference numerals
The description and the drawings use the following
reference numerals:
10 tree-felling machille
10 12 logging vehicle
14 boom plane
2 o boom
22 proximal boom member
24 distal boom member
15 26 boom hydraulic actuator
28 boom hydraulic act~lator
30 boom hydraulic actuator
32 first lever
34 second lever
20 40 tree-felling imple~ent
42 frame
44 trunk grabbing arm6
46 hydraulic actuators ~of the trunk grabbing arms)
48 circular saw
25 49 protective cacing
50 implement pivot
52 linking element
54 first pivot (of the boom linking element)
56 second pivot (of the boom linking element)
30 60 actuating rs~hAni ~:m
62 pinion
G4 pinion teeth
66 arc-shaped rack
68 rack teeth
35 70 rack pivot
72 rack hydraulic actuators
74 rack lateral locations
General description of t~le invention
A6 shown in FIG. 1, the tree-felling machine (10)
compri~es a self-propelled logging vehicle (12) adapted for
use on logging sites and controlled by an operator sitting
inside a cabin thereof. As apparent for a person skilled in
45 the art, many other kind~ of logging vehicles can be used
instead of the one illustrated in FIG. l.
21~7~9
An articulated boom (20) is operatively mounted on
the vehicle (12). This L-~oom (20) is known as a felling boom
or a tree boom. Its purpose is to allow movement of a tree-
felling implement (40) in the vertical plane. The implement
5 (40) is rotatably connected at the distal end of the boom
(20) by means of an impLement pivot (50). The boom (20) is
described in details further in the text.
The tree-fel]ing implement (40) is used for
cutting down the trees instead of using a manual chain saw.
10 In use, to cut down an a~jacent tree, the operator moves the
implement (40) towards the base of the tree. The implement
(40) then grabs a trunk ~ith a set of hydraulically actuated
trunk grabbing arms ( 44 ) and cut the trunk at the base with
a circular saw (48). ALternatively, a felling shear (not
15 shown) may be used. The trunk is laid down on the ground or
in a truck afterwards. The implement (40) is described in
details further in the text.
Because the baom ( 20 ) is generally moving only in
the vertical plane, hereinafter referred to as "the boom
20 plane (14)", the implement (50) has to be able to rotate
around the implement p ivot ( 50 ) so that it may grab an
inclined or curved tree, or a tree laying on the ground. The
present invention provicles a simple and reliable r-~ hAni Fm
(60) capable of rotatincl the implement (40) with reference
25 to the boom plane ( 14 ) in both directions, clockwise and
counterclockwise, and capable of having a wide range angle.
Although the present invention allows the implement (40) to
have range angles of gO~ and over, one may choose to
restrict the range angle to a value under 45 and use the
30 r~^hAni~m (60) of the present invention for its other
advantages. Uneven extreme angles with reference to the boom
plane ( 14 ) are also possible if desired. The actuating
r- hAn;Fr (60) is described in details further in the text.
21~67~ 9
The boom
The boom (20) comprises a proximal boom member
5 (22) and a clistal boom member (24) operatively connected to
each other. The proximal boom member (22) i5 operatively
connected to the vehic!le ( 12 ) and is rotated by mean5 of a
hydraulic actuator ( 26 ) of the boom. The distal boom member
(24) is rotated with reference to the proximal boom member
10 (22) by means of a hydraulic actuator (28) of the boom.
Specific construction details are known in the art of heavy
machinery .
In addition 1:o the movement in the vertical plane,
the boom (20) may be articulated at this proximal end (not
15 shown) for left and right rotations with reference to the
vehicle (12). Alternatively, the vehicle (12) may be able to
turn on itself, as it is the case for the one illustrated in
FIG. 1.
The boom ( 20 ) comprises other elements that are
20 described further in tlhe text.
The tree-felling implelnent
The tree-fel] ing implement (40) itself is a device
25 known in the art . It comprises a main frame ( 42 ) on which is
located a trunk grabbi]lg means, such as the trunk grabbing
arms (44) actuated by the hydraulic actuators (46). The
implement further comprises a circular saw (48), as best
shown in FIG. 3, and a protective casing ( 49 ) therefor.
30 Other tree cutting means, such as a felling shear (not
shown) may be used instead of the saw (48).
The implement pivot ( 50 ) is a bearing supporting
the weight of the implement ( 40 ) and of a tree when one is
in the implement (40). It comprises the usual parts for such
35 a bearing, as apparent for a person skilled in the art.
214~
The actuating r~^hAnif:l~ for rotating the implement
The actuating ~ h;lni~:~ (60) compri6es a pinion
(62) coaxial with the implement pivot (50), more precisely
with the center of rotation thereof. The pinion (62) ie
fixed in rotation with reference to the distal end of the
boom ( 2 o ) .
The r^-h;~ni~rl (60) further comprises an arc-shaped
rack ~66) rotatably mounted on the frame (42) of the
implement (40) by a rack pivot (70) in spaced relationship
with the pinion (62), more precisely its center. The rack
pivot ( 70 ) is in spaced relationship with the center of the
pinion (62) so that a virtual mechanical lever arm is
defined. The rack (66~ preferably has teeth (68) in mesh
with corresponding teeth ( 64 ) on the pinion ( 62 ) .
An actuating means is provided on the frame (42)
of the implement (40) for swaying the rack (66). The
actuating means preferably compriseg two reciprocal
hydraulic actuators (72) ~ymmetrically disposed about the
rack (66). The actuators (72) have one end operatively
connected to the frame (42) of the implement (40), and
another end operatively connected to the rack ( 66 ) on a
respective lateral location (74) thereon with reference to
the rack pivot ( 70 ) . The lateral locations ( 74 ) are in
spaced relationship with the rack pivot (70) for defining
virtual mechanical lever arms by which the force applied by
the actuators ( 72 ) is converted into a torque, itself
transmitted to the pinion (62).
Upon activation of the actuators (74), which move
reciprocally, they apply a force resulting in a torque that
rotates the rack (66) around the rack pivot (70). Because
the implement ( 40 ) is l^otatably connected to the boom ( 20 )
and the pinion (62) is Eixed in rotation with respect to the
boom (20), the movement of the rack (66) rotates the whole
implement (40) around the implement pivot (50).
Of course, other actuating mechanisms and
arrangemente are also possible. For example, the actuating
means may comprise a hydraulic motor (not shown).
5 The linking element
The linking element ( 52 ) is used for rotatably
connecting the implement ( 40 ) to the distal end of the
distal boom member ( 24 ) . According to a preferred
10 embodiment, as shown in FIG. 1, the linking element (52)
comprises a first pivot (54), for connecting the implement
(40) to the boom (20). A second pivot (56) is provided,
closer to the frame (42) than the ~irst pivot (54) for
rotatably connecting the implement (40) to an end of a first
15 lever (32). The first lever (32) has an opposed end
rotatably connected to a hydraulic actuator (30) of the
boom. The same end of tne first lever (32) is also rotatably
connected to an end of a second lever (34). The second lever
(34) has an opposed en~ rotatably connected to the boom
20 (20). ~ith this arrangement, the linking element (52) is
moved in the boom plane ( 14 ) whenever the hydraulic actuator
( 30 ) is operated, thereby also moving the implement ( 40 ) in
the boom plane (14).
25 Scope of the present desaription
Although a preferred embodiment of the invention
has been described in detail herein and illustrated in the
accompanying drawings, it is to be understood that the
30 invention is not limited to this precise e~ 7--t and that
various changes and modifications may be effected therein
without departing from the scope or spirit of the invention.
