Note: Descriptions are shown in the official language in which they were submitted.
~S~}25
The present invention relates to an apparatus for
felling trees and more particularly to a feller head
attachment for mounting on a vehicle~
m ere are several different types of feller heads
which have been developed over the past twenty years. These
attachments have in common, a frame mounting vertically
oriented feller head grapple arms for holding the tree to be
felled, and a cutting device at the bottom of the frame for
severing the trunk of the tree. Several cutting devices have
been described including wedge shears, chain saws and rotary
saws.
On some feller heads, an accumulation device has
been provided for holding previously cut trees in the felling
head while a further tree is being cut. The accumulation
feature is especially important in areas where the timber
tends to be of the small diameter variety such as found in
eastern Canada, so as to ~aintain an economic harvesting
yield from such equipment. Usually such an accumulation
device is in the form of an additional grapple arm adapted
to be closed onto the accumulated trees in the grapple area
when the grapple arms are being opened to embrace a further
tree to be cut. When the grapple arms are once again closed
on the accumulated trees including the most freshly cut tree,
the accumulation arm is withdrawn to an open position.
Because these arms are the only elements supporting the cut
trees in a vertical accumulated position, the pressure on the
arms required to hold the trees is often sufficient to damage
some of the trees and even break smaller trees.
It is an aim of the present invention to provide an
improved tree felling head having an accumulation feature
which avoids some of the disadvantages mentioned above.
~2~2~25
A construction in accordance with the present
invention comprises a tree felling apparatus including an
upstanding frame, a base plate fixed to the bottom of the
frame and defining a notch open to the front of che base
plate and adapted to receive a tree to be cut. A second plate
is pivotally mounted to and parallel to the base plate, and
adapted to move in an arc across the n~tch of the base plate.
The second plate has a leading edge. A chain saw is provided
wherein the chain is driven to move along the leading edge
of the second plate whereby the chain saw will sever a tree
in the notch when the second plate is pivoted across the notch~
Grapple arms are mounted on a su~frame mounted on the second
plate, and the second plate presents a tree support surface
between the subframe and the leading edge such that the
grapple means can accumulate trees on the second plate and
against the subErame.
In a more specific embodiment, second grapple means
are provided on the frame in order to hold a tree when a tree
is wi~hin the notch.
Having thus generally described the nature of the
invention, reference will now be made to the accompanying
drawings, showing by way of illustration, a preferred embodiment
thereof, and in which:
Figure 1 is a perspective view of a felling head in
accordance with the present invention,
Figure 2 is a top plan view of the felling head shown
in figure 1 in an operative position
prepared to receive a tree to be severed, and
Figures 3 through 6 are top plan views similar to
figure 2 but showing the felling head in
different sequential operating positions.
-- 2
~2~ S
Referring now to the drawings particularly to figure
1 a felling head 10 includes a base plate 12 to which a frame
14 is fixed. The frame 14 and base plate 12 subtend a column
16. A support plate 18 is pivotally mounted on the base plate
12 and journaled on the column 16. A chain saw 20 runs along
the edge of the support plate 18.
The frame 14 includes a frame housing 22 and a top
plate 24. m e rear of the frame housing 22 is provided with a
mounting bracket 26 adapted for mounting on the front of the
vehicle. Sitting on the top plate 24 is a grapple bracXet
27 pivotally mounting grapple arm 28 which is adapted to pivot
about pivot pin 30. A lever bracket 32 is provided on the hub
of the grapple arm 28. Ihe grapple arm 28 is divided into two .
sections, a first arm portion 34 fixed to the hub and a :
pivoting arm portion 36 pivotally connected by means of a
pivot pin 37 to the first arm portion 34. The grapple arm is
operated b~ means of a hydraulic cylinder and piston arrangement
38 which is mounted to a bracket 40 at one end on the top plate
~4 and the other end to the lever bracket 32. The top plate 24
2Q is provided with a notch 42 which corresponds vertically with
the notch 46 in the base plate 12. An arm 44 in the top plate
24 is formed by the notch 42.
The base plate 12 includes a notch 46 for receiving
the tree which corresponds to the notch 42 in the top plate 24
which defines an arm 48.
The column 16 includes a shaft extending in the
interior of a tube 50 which is journaled on the base plate 12 and
to the top plate 24. The tube 50 mounts grapple arms 52 and 54
as well as a bracket 58. The grapple arms 52 and 54 are fixed
to the tube and are rotatable relative to the shaft 56. A
hydraulic piston and cylinder arrangement 60 is mounted to a
~s~s
bracket 62 on the frame housing 22 and to the lever bracket
58 on the tube 50. Operation o~ the piston and cylinder
arrangement will cause the tube 50 to rotate moving the
grapple arms 52 and 54.
The support plate 18 includes a plate section 64 pro-
vided with peripheral plate members 68 and 70 which extends
along three sides of the plate 64. The fourth side is
uncovered and includes a leading edge 66. The peripheral
plates 68 and 70 define a chain run 72 for the chain saw 20.
m e leading edge 66 defines a narrow slot along the edge
adapted to receive trailers on the chain saw 20. Rollers 74
are provided at each corner of the support plate 18 between
the peripheral plates 68 and 70 and a drive motor 76 which may
be a hydraulic motor is provided at one corner for driving the
chain 20. The plate 64 has a portion thereof which has been
machined to form a taper from the leading edge 66. The
machined portion is identified by numeral 78 in the drawings.
The support plate 18 mounts a subframe 79 made up of
columns 80 and 82 and a horizontal cross bar 92. The column 80
is rotatable and mounts grapple arms 84 and 84a. The arm 84a is
identical to the arm 84 and elements thereof are identified by
similar reference numbers raised by the subscript a. Grapple
arm 84 therefore includes fixed arm portion 86 mounted to the
column 80 and a pivoting arm portion 88 which is pivotally
mounted to the portion 86 by means of a pivot pin 90 which is
spring biased. A piston and cylinder arrangement 94 is mounted
to a bracket 98 fixed to the column 82 at one end thereof and
to a lever bracket on the rotatable column 80.
In operation, the felling head 10 is advanced on
the front of the vehicule to a tree T to be cut. As the tree T
is aligned and enters the notch 42 and 46 in the top plate and
base plate respectively, the grapple arms 28, 52 and 54 will
be operated to c:Lose onto the trunk of the tree T and hold the
125~S
trunk. Once the tree T is in the position~ as shown in
figure 3, with the grapple arms 28, 52 and 54 securily onto
the trunk of the tree, the piston and cylinder arrangem~nt
96 will be operated to pivot the support plate 18 about its
pivot axis with the column 16 to move in an arcuate path
across the notch 46. As the leading edge 66 of the support
plate 18 encounters the tree T, the chain saw 20 driven by the
motor 76 will be operated to cut its way through the tree. As
the support plate 18 advances with the leading edge 66 and
chain 20 passing through the tree in its cutting path the
tapered surface 78 of the support plate 18 will wedge itself
in the cutting path of the tree thereby partially supporting
the weight of the tree as the chain 20 continues its way
through the diameter of the tree.
Once the tree has been completely severed as shown
in figure 5 the support plate 18 will have been pivoted
completely across the notch 46 and the base of the tree T will
rest on the surface of the support surface 64 of the support
plate 18. At the same time, the grapple arms 84 and 84a will
have advanced as shown in figure 5 to encircle the tree T.
The grapple arms 28 and 52 are then retracted so as to be clear
of the tree T and the support plate 18 and the subframe 79 is
moved back along its arcuate path with the accumulator grapple
arms 84 and 84a retaining the severed tree against the subframe
arm 79.
In the next cycle, when there is already one or more
trees accumulated against the subfràme 79, the operation of the
grapple arms 28 and 84 will cause the spring urged pivoting
portions of the arms to pivot as the arms are being removed
~rom between the trees being accumulated as is known in the art.
