Tree harvester

PCT No. PCT/US79/00131 Sec. 371 Date Mar. 5, 1979, Sec. 102(e) Date Mar. 5, 1979 PCT Filed Mar. 5, 1979 PCT Pub. No. W080/01865 PCT Pub. Date Sept. 18, 1980. A tree harvester (12) is provided with an apparatus (20) for accumulating trees, one at a time. The apparatus includes a single, multiple accumulator arm (58) which has three joined members (30,40,50). A first member (30) is pivotally connected to the frame (18) of the tree harvester (12) and the second member (40) is pivotally connected to the first member (30) and movable relative to the first member (30) between an open position and a closed position. The second member (40) is maintained in one of the open and closed positions during pivotal movement of the first member (30). A third member (50) is pivotally connected to the second member (40) and biased so that it can be folded and removed from between a tree (26) and the frame (18) and unfolded to later accumulate trees against the frame (18). This simple structure uses only one movable accumulator arm (58) instead of two.

TECHNICAL FIELD 
This invention relates to tree harvesting machine equipped with an 
apparatus for accumulating the trees one at a time and, more particularly, 
to accumulators having only one movable arm for accumulating trees one at 
a time. 
BACKGROUND ART 
In recent years, the cost of harvesting trees has increased thereby 
compelling a search for more economical harvesting methods and apparatus. 
In the pioneer days, trees were manually harvested one at a time with an 
axe or saw. This method was satisfactory for pioneer days but as the 
demand for lumber grew, more productive methods were discovered. Today, 
there is a variety of logging equipment including tree fellers, debarkers 
and delimbers which greatly increase productivity. It is desirable to 
further increase productivity. 
To increase productivity tree fellers have been constructed which severe 
several small trees at one time. While this has the advantage of saving 
time, it is useful only with small trees which grow very close together. 
Normally, larger trees are cut one at a time and individually moved or 
stacked so that the tree harvester can proceed to the next tree. A certain 
amount of time is involved in moving or stacking cut trees and during this 
time the tree harvester is not cutting other trees and is therefore 
unproductive. Recent tree harvesters have been equipped with accumulators 
which accumulate cut trees one at a time and hold the trees until it is 
filled to its capacity of several trees. The trees are then stacked or 
gang loaded for transport in about the same time it takes to stack or load 
a single tree. While this is an improvement, there is still a need to be 
more economical. Apparently, the machines are operated at full human 
capacity; so, any improvements must relate to the machines themselves. 
The state of the art of accumulators for tree harvesters is exemplified by 
the following U.S. Pat. Nos.: 
______________________________________ 
U.S. Pat. No. Date Inventor 
______________________________________ 
3,664,391 May 23, 1972 H. D. Coffey 
3,805,860 April 23, 1974 
L. N. Smith 
3,875,983 April 8, 1975 
J. Kurelek 
RE 29,235 May 31, 1977 J. Kurelek 
3,886,985 June 3, 1975 A. Larocci et al 
3,910,326 Oct. 7, 1975 F. Tucek 
3,911,981 Oct. 14, 1975 
F. Tucek 
______________________________________ 
U.S. Pat. Nos. 3,875,983, RE 29,235, and 3,886,985 are similar in 
construction and operation and each utilize two pairs of movable arms. 
Each arm of each pair of arms is pivotally movable requiring complicated, 
and therefore expensive, parts and connections to achieve the movement. 
Similarly, U.S. Pat. No. 3,664,391 uses two pairs of complicated arms with 
each arm of each pair of arms being pivotally movable. It is therefore 
desirable to have pairs of arms in which each arm is more simply 
constructed. 
U.S. Pat. No. 3,805,860 uses a single arm for holding the severed trees 
instead of a pair of arms. Unfortunately, two hydraulic cylinders are 
required to manipulate the tree accumulating arm so as to remove it from 
between the accumulated trees and a tree to be accumulated. Obviously, two 
cylinders double the changes for breakdown or failure and add to the cost 
and complexity of the accumulator arm as compared with using a single 
cylinder. 
U.S. Pat. No. 3,911,981 uses a single, movable arm for accumulating trees; 
however, the arm comprises a compound linkage arrangement which, while 
reducing the number of extra cylinders to zero, is nevertheless a 
complicated structure. U.S. Pat. No. 3,910,326 has a simpler structure 
than U.S. Pat. No. 3,911,981. They both have chains, however, which can 
slip off their sprockets in a logging environment. It is therefore 
desirable to have a simple accumulator mechanism which can hold and 
accumulate harvested trees and perform in a logging environment. 
DISCLOSURE OF INVENTION 
The present invention is directed to overcoming one or more of the problems 
as set forth above. 
According to the present invention, a tree harvester is provided with an 
apparatus for accumulating trees, one at a time. The apparatus includes a 
first member pivotally connected to the frame of the tree harvester. A 
second member is pivotally connected to the first member and movable 
relative to the first member between an open position and a closed 
position. Means are provided for maintaining the second member in one of 
the open and closed positions during pivotal movement of the first member. 
A third member is pivotally connected to the second member and movable 
between an open position and a closed position and biased toward the open 
position.

BEST MODE FOR CARRYING OUT THE INVENTION 
Referring to FIG. 1, a vehicle, such as an excavator 10, is equipped with a 
tree harvester attachment 12 connected to the stick and boom of the 
excavator 10. The tree harvester 12 is movable, vertically and laterally, 
as a regular excavator bucket would be movable. The tree harvester 12 has 
a pair of grapple arms 14 and a pair of shears 16 mounted on an upright 
frame 18. The shears 16 are positioned below the grapple arms 14 and are 
both controlled by fluid cylinders (not shown) as is known in the prior 
art. 
Referring to FIGS. 1 and 2, a tree accumulating apparatus 20 is attached to 
the frame 18 and positioned intermediate the grapple 14 and shears 16. The 
tree accumulating apparatus 20 includes a support member 22 which is 
connected to the frame 18 and which has a curved edge portion 24 for 
receiving one or more trees 26. There are preferably two support members 
22 connected to the frame 18 and vertically spaced a preselected distance 
one from the other. 
Referring to FIGS. 2 and 3, the tree accumulating apparatus 20 also 
includes a mounting bracket 28 which is connected to the frame 18. A first 
member 30 has a first end portion 32 pivotally connected to the bracket 
28, a second end portion 34, and a longitudinal axis 36. A second member 
40 has first and second end portions 42,44, a middle portion 46, and a 
longitudinal axis 48. The middle portion 46 is pivotally connected to the 
second end portion 34 of the first member 30. A third member 50 has a 
first end portion 52 pivotally connected to the second end portion 44 of 
the second member 40, a second, free end portion 54, and a longitudinal 
axis 56. The three members 30,40 and 50 comprise an accumulating arm 58. 
Referring to FIG. 2, means, such as fluid cylinder 60, are provided for 
pivotally moving the second member 40 about the second end portion 34 of 
the first member 30. The cylinder 60 has its head end pivotally connected 
to the bracket 28 and its rod end pivotally connected to the first end 
portion 42 of the second member 40. The manner in which the cylinder 60, 
first member 30 and second member 40 are interconnected facilitates 
movement of both members 30,40, as will be more fully explained below. 
Means, such as hook 62 and pin 64, are provided for limiting the pivotal 
movement of the first member 30 relative to the bracket 28 to a value 
within a range of about 0 to 25 degrees. The hook 62 is preferably 
connected to the first member 30 and the pin 64 preferably protrudes 
vertically from the bracket 28. As an alternative to the hook 62, a 
slotted link can be used. The slotted link can have a simple slot and be 
pivotally connected to one of the first member 30 and bracket 28 or can be 
nonpivotally attached and have a triangular slot. 
Referring to FIG. 3, the third member 50 is movable relative to the second 
member 40 between a first, open position at which the axes 48,56 of the 
second and third members 40,50 are generally aligned and a second, closed 
position at which the second, free end 54 of the third member 50 is 
displaced toward the second member 40. At the second position the axes 
48,56 form a preselected angle. 
Biasing means, such as a roll spring 66, urges the third member 50 towards 
the first position. 
The second member 40 is movable relative to the first member 30 between an 
open position and a closed position. Means, such as over-center spring 70, 
is provided for holding the second member 40 in one of the open and closed 
positions. The over-center spring 70 is preferably a coil spring which has 
one end connected to the first member 30 and the other end connected to 
the second member 40. 
The coil spring 70 is preferably positioned about a bracket 72 which has a 
cap portion 73 connected to the first member 30 and a slotted end portion 
74. The end portion 74 fits on a pin 76 and is slidably movable on the pin 
76. A washer 78 and the cap 73 keep the spring 70 on the spring bracket 72 
in a compressed state. 
The pin 76 is positioned at a location on the middle portion 46 of the 
second member 40 and is on the axis 48. When the second member 40 is in 
its open position the cap portion 73 and the spring 70 are on one side of 
the axis 48 and when the second member 40 is in its closed position the 
cap 73 and spring 70 are on the other side of the axis 48. 
Referring to FIGS. 4-7, the accumulating arm 58 is shown as it moves from a 
fully open position (FIG. 4) to a fully closed position (FIG. 6). At the 
fully open position, the first and second members 30,40 are each in their 
open position, the cylinder 60 is fully retracted, and the free end of the 
hook 62, the end nearest the frame 18, is contacting the pin 64. At the 
fully closed position, the first and second members 30,40 are each in 
their closed positions, the cylinder 60 is fully extended, and the fixed 
end of the hook 62, the end of the hook 62 fixed to the first member 30, 
is contacting the pin 64. By fully extended it is meant that the cylinder 
rod 61 is moved away from the cylinder head 59 a maximum distance 
increasing the effective length of the cylinder 60 and by fully retracted 
it is meant that the cylinder rod 61 is moved toward the cylinder head 59 
a maximum distance decreasing the effective length of the cylinder 60. 
At the partially open position shown in FIG. 5, the first member 30 is in 
its closed position, the second member 40 is in its open position, and the 
cylinder is partially retracted or extended as would be the case when the 
arm 58 is moving from its fully open position (FIG. 4) to its fully closed 
position (FIG. 6). The fixed end of the hook 62 is contacting the pin 64. 
This is the position assumed by the arm 58 immediately before the second 
member 40 closes upon the application of sufficient force by the cylinder 
60. 
At the partially closed position shown in FIG. 7, the first member 30 is in 
its open position, the second member 40 is in its closed position, and the 
cylinder is partially extended or retracted as would be the case when the 
arm 58 is moving from its fully closed position (FIG. 6) to its fully open 
position (FIG. 4). The free end of the hook 62 is contacting the pin 64. 
This is the position assumed by the arm 58 immediately before the second 
member 40 opens upon the application of sufficient force by the cylinder 
60. 
As the accumulating arm 58 is closed from its fully open position (FIG. 4) 
by the extension of the cylinder 60 from its fully retracted position, the 
over-center spring 70 holds the second member 40 in its open position with 
respect to the first member 30 until the fixed end of the hook 62 contacts 
the pin 64 preventing further rotation of the first member 30 with respect 
to the frame 18. This resulting position is depicted by FIG. 5. 
Further extension of cylinder 60 past the position shown in FIG. 5 requires 
the cylinder force to overcome the holding force of the over-center spring 
70 to move the second member 40 with respect to the stationary member 30. 
This motion continues as the cylinder 60 extends until a tree 26 is 
clamped against support member 22 or until cylinder 60 is fully extended 
if no tree is being clamped. This occurs at the end of each cycle when 
both the accumulator arm 58 and the grapple 14 are opened simultaneously 
to release the load of trees and the accumulator arm 58 is then allowed to 
close to its normally closed position (FIG. 6). In its normally closed 
position (see FIGS. 6 and 2) the accumulator arm 58 lies entirely behind 
the cradle created by the curved edge of support member 22 and therefore 
does not interfere with one-at-a-time harvesting of large trees. For large 
trees the accumulator arm 58 can remain in its relatively protected 
normally closed position. 
The closing path of the accumulating arm 58 has two distinct segments as 
indicated by dashed lines 80 and 82 (FIG. 2). The first distinct segment 
80 results from the movement of the accumulating arm 58 from the position 
shown in FIG. 4 to the position shown in FIG. 5 30. After the fixed end of 
the hook 62 contacts, the pin 64 (FIG. 5), the tip 54 of the arm 58 
pivotally moves about the second end 34 of the first member 30 
circumscribing distinct arcuate segment 82 which results in essentially 
rearward motion and therefore rearward clamping effort of arm 58. Rearward 
clamping effort is required to clamp the tree 26 against the support 
member 22. 
As the arm 58 is opened from its fully closed position (FIG. 6) or another 
tree holding position by the retraction of the cylinder 60, the 
over-center spring 70 holds the second member 40 in its closed position 
with respect to the first member 30 until the free end of hook 62 contacts 
the pin 64 preventing further rotation of the first member 30 with respect 
to the frame 18. This resulting position is depicted by FIG. 7. 
Further retraction of cylinder 60 requires the cylinder force to overcome 
the holding force of the over-center spring 70 to move the second member 
40 with respect to the stationary member 30. This motion continues as the 
cylinder 60 retracts fully to the position shown in FIG. 4. 
Like the closing path, the opening path of arm 58 has two distinct 
segments, the first in an essentially lateral movement of the arm 58 due 
to rotation of the members 30,40,50, about the end 32 of member 30 until 
the free end of the hook 62 contacts the pin 64. The primarily lateral 
movement of the arm 58 and freedom of member 50 to pivot toward the frame 
18 easily enables the arm 58 to be pulled free from behind the severed 
trees or from between two severed trees. In the second part of the motion 
the arm 58 pivots about the end 34 of stationary arm 30 until the cylinder 
60 is fully retracted and the arm 58 is in the fully open position (FIG. 
4). 
INDUSTRIAL APPLICABILITY 
In operation, the excavator 10 is driven close to the trees to be harvested 
and stopped. The stick and boom of the excavator 10 are extended to move 
the tree harvester attachment 12 from tree to tree during operation of the 
tree accumulating apparatus 20. The accumulated trees can be conveniently 
moved and stacked by manipulating the stick and boom or by propelling the 
excavator 10. 
Referring to FIG. 2, the accumulating arm 58 is closed or retracted so that 
the third member 50 is displaced toward the frame 18 and lies between the 
two vertically spaced support members 22. In this retracted position, the 
accumulating arm 58 is close to the frame 18 and the risk of becoming 
entangled with tree branches or other trees is minimized. 
With the shears 16 and grapple 14 in their open positions, the tree 
harvester 12 is moved to the tree 26. The grapple arms 14 are closed 
around the tree 26 and the tree 26 is positioned against the curved edge 
24 of the support member 22. The shears 16 are closed about the tree 26 to 
sever it from its base. At this time, the grapple arms 14 hold the tree 26 
against the support member 22 while the shears 16 provide vertical 
support. 
At this time, the arm 58 is still retracted with the first member 30 in its 
first, closed position, the second member 40 in its first, closed 
position, and the third member 50 in its first, open position. While the 
shears 16 and grapple 14 secure the cut tree 26, the arm 58 is opened and 
then closed to accumulate and hold the tree 26. 
To open the arm 58, the cylinder 60 is retracted causing the first member 
30 to pivot from its first, closed position to its second, open position. 
The pivotal movement of the first member is stopped by the limiting means 
62 when the end of the hook 62 nearest the frame 18 contacts the pin 64. 
As the first member 30 pivots, the third member 50 pivots from its first, 
open position to its second, closed position so that it is withdrawn from 
between the tree 26 and frame 18. When the third member 50 is clear of the 
tree 26, the biasing spring 66 urges the third member 50 toward its first, 
open position. Depending on the diameter of the tree 26, the third member 
50 may not be returned to its open position merely in response to the 
first member 30 moving to its open position. For example, with a small 
tree the third member 50 may return to its open position, while it may not 
return with a somewhat larger tree. 
To insure that the third member 50 does return to its open position, the 
second member 40 moves from its first, closed position to its second, open 
position thereby withdrawing the free end 54 of the third member 50 from 
the tree 26. Because of the over-center spring 70, the second member 40 
cannot move from its closed position to its open position until the first 
member 30 moves to its open position wherein the end of the hook 62 
nearest the frame 18 abuts the pin 64. By having the second member 40 
remain closed, the third member 50 is first moved laterally, then 
pivotally which allows it to slip from between the tree 26 and support 22 
without expending effort to move the tree 26. 
When the first member 30 moves to its open position, the second member 40 
moves from its closed position to its open position upon the urging of the 
retracting cylinder 60 which pivots the second member 40 about the second 
end 34 of the first member 30. Thus, the cylinder 60 actually moves both 
members 30,40. This pivotal movement of the second member 40 causes the 
third member 50 to pivot if the free end 54 of the third member 50 has not 
cleared the tree 26. 
When the second member 40 is in the closed position, the force exerted by 
the cylinder 60 tending to pivot the second member 40 about the first 
member 30 must overcome the force of the spring 70 which tends to keep the 
members 30,40 in the closed position. When the force is overcome, the 
second member 40 moves toward its open position. 
When the arm 58 has cleared the tree 26, the cylinder 60 is extended to 
close the arm 58 around the tree 26 with the third member 50 positioned on 
one side of the tree 26 and the curved edge 24 of the support member 22 on 
the other side of the tree 26. The arm 58 securely holds the tree 26 when 
the shears 16 are opened and their vertical support is removed. The 
grapple arms 14 are opened to receive a succeeding tree against the third 
member 50 and first tree 26. The grapples 14 are then closed to hold the 
succeeding tree which is then severed by the shears 16. The arm 58 is 
withdrawn as previously described and then closed to securely hold and 
accumulate both the original tree 26 and the succeeding tree. This process 
is repeated until the capacity of the tree accumulating apparatus 20 is 
reached. 
Other aspects, objects and advantages of this invention can be obtained 
from a study of the drawings, the disclosure, and the appended claims.