Mobile machine for processing trees and trunks

An apparatus for delimbing previously cut trees having a tree delimber unit carried by a mobile vehicle and having an hydraulic power cylinder for pivoting the delimber unit from one side of the vehicle to the other so as to counter-balance the weight of a tree collecting mechanism.

Mobile machines for tree-delimbing purposes are previously known. Said 
machines besides being provided with a delimbing apparatus are often 
provided with a rotatable crane with a gripping device for feeding the 
trees into the delimbing apparatus, or with a device for severing and 
felling trees, and this has contributed to the weight of the machine 
becoming considerable. Thus, modern logging machines have tended to be 
heavier and more expensive so that the use thereof is not profitable other 
than for clear-cutting of forest stands. The weight of the machines also 
has the result that the mobility of the machines is limited by the bearing 
properties of the soil. For heavy logging machines can sometimes cause 
damage in the ground surface which is difficult to repair. Besides, such 
machines have the disadvantage not to be suitable for thinning in a forest 
stand because of their heavy and complicated structure and also because of 
their lower working capacity in thinning operations. One reason why this 
development, which has led to bigger and bigger machines, has not been 
considered as negative can be explained by the fact that the mere weight 
of such machines give them a good lateral stability, which means that the 
lifting capacity and the lifting range of the crane mounted on such 
machines can be considerable without jeopardizing the side or lateral 
stability of the machines. 
The present invention makes it possible to reduce the weight of a mobile 
logging machine without jeopardizing the stability. A machine according to 
the invention can be used with advantage for delimbing and cutting tree 
trunks not only in a clear-cutting operation but also in a thinning 
operation. 
A mobile machine according to the invention for treating trees and trunks 
comprises a mobil carrier vehicle, a log-treating apparatus carried by 
said vehicle and a device mounted on the vehicle for gripping trees or 
trunks spaced from the vehicle for the purpose of feeding same to the 
log-treating apparatus, and the machine is characterized according to the 
invention in that the log-treating apparatus for substantially increasing 
the lateral stability of the machine is shiftable with respect to the 
vehicle by means of motor means in such a manner that the centre of 
gravity thereof can be moved to a considerable extent in both lateral 
directions from a vertical centre plane through the vehicle in the 
direction of length thereof. 
According to one embodiment of the invention the log-treating apparatus is 
swingably connected to the vehicle in such a manner that it can be swung 
in the transverse direction thereof. The swinging axis is in this case 
preferably vertical. The log-treating apparatus can be pivotally connected 
to and carried by the vehicle by means of one or more pivot arms, for 
instance one or more arms extending from the vehicle, for instance from an 
end portion thereof. In order to make it possible to effect a sometimes 
desirable inclination of the log-treating apparatus with respect to the 
ground plane the apparatus can further be swingable about a substantially 
horizontal axis extending perpendicularly to a vertical plane through the 
feeding path of the log through the apparatus. 
For shifting the log-treating apparatus in the manner mentioned above the 
apparatus can, however, be movable otherwise, for instance slidably in the 
transverse direction of the vehicle, suitably by attaching the apparatus 
to the vehicle by means of a guide extending substantially in the 
transverse direction of the vehicle. 
Besides being shiftable in the manner mentioned above the log-treating 
apparatus can be adapted to the adjustable - in dependence or 
independently of said shiftability - to a position in which tree trunks 
treated by said apparatus are delivered at the side of and preferably 
substantially parallel with the direction of length of the vehicle. 
The invention is especially suitable to be used in mobile machines provided 
with a delimbing apparatus and a crane turnable around the vehicle and 
provided with gripping means for trees for the purpose of feeding the 
latter into the delimbing apparatus. 
Since the log-treating apparatus is shiftably mounted on the carrier 
vehicle in the manner described above the machine operator can use the 
apparatus as a counterweight during the operation of the lifting crane for 
feeding trees and trunks to the log-treating apparatus. In this manner the 
above mentioned increase of the lateral stability of the machine is 
attained so that the stability of the machine is no longer dependent 
merely on the weight of the machine and the track gauge of the vehicle. 
Since the stability of the machine is improved by the shiftability of the 
log-treating apparatus with respect to the carrying vehicle the weight of 
the machine can be reduced to a considerable extent and it can be possible 
to provide a single motor for the propagation of the vehicle and for 
driving the crane and the log-treating apparatus.

In the embodiment shown in FIG. 1 the machine comprises a base or carrier 
vehicle 1 in the form of a so called waist-steered four-wheeler. The 
vehicle carries a lifting crane of which only the crane mast 2 is 
indicated. The crane is of conventional type preferably a hydraulically 
driven crane provided with means for gripping trees and feeding same 
towards the log-treating apparatus 3 which in this case is a branch 
removing apparatus. The machine propagates stepwise in the direction of 
the arrow A. 
The branch removing or delimbing apparatus 3 is carried by an arm 4 which 
is swingably connected to the chassis 1a of the vehicle 1 by means of a 
pivot 9 having a vertical pivot axis. The length of the arm 4 is such that 
the delimbing apparatus 3 can be swung laterally in both directions 
relatively to a vertical centre plane through the vehicle in the direction 
of length thereof, i.e. a vertical plane through the axis 9 in the 
direction of length of the vehicle, to such an extent that the centre of 
gravity of the apparatus is situated laterally in line with the carrying 
wheels of the vehicle or even laterally outside said wheels in each 
extreme lateral position. In this manner it is possible when lifting a 
tree situated at one side of and at a large distance from the machine 
using the crane 2 to stabilize the machine laterally by swinging the 
delimbing apparatus towards the opposite side to a sufficient degree. This 
presupposes that the delimbing apparatus has a considerable weight. The 
weight of the apparatus can be at least 1/3 tons, suitably at least 1/2 
tons. Delimbing apparatuses having preferably hydraulically driven feed 
rollers for feeding the tree trunks are especially suitable in the present 
connection, since they have a considerable weight and can easily be 
completed with further log-treating units, for instance a cutting device 
for the trunks. 
The placing and orientation on the machine of the delimbing apparatus 3 
according to the figures make it possible to delimb the trees and place 
the delimbed trunks at the side of the machine. By turning the delimbing 
apparatus 3 on the arm 4 the apparatus can be set in other desired 
directions. 
The delimbing apparatus 3 can be of a conventional type having rotating 
feed rollers 5 provided with short spikes at the periphery thereof for 
improved gripping action against the tree trunk and knives 6 for delimbing 
the tree can be movable by means of hydraulic devices in a manner known 
per se. A device (not shown) for cutting the trunks is preferably mounted 
after the delimbing apparatus 3 as seen in the direction of feed of the 
tree. 
Hydraulic motor means 8 connected between the arm 4 and the apparatus 3 can 
be used for pivoting the apparatus 3 relatively to the arm 4. The 
delimbing apparatus 3 is carried by the arm 4 by means of a joint 7 having 
a vertical axis of rotation. 
In FIG. 2 the possibility of swinging the delimbing apparatus 3 with the 
arm 4 is illustrated as is the possibility of turning the apparatus on the 
arm. The swinging or turning movement about the axis 9 is effected in a 
simple manner by means of known motor devices for instance hydraulically 
operated means which are not shown on the drawing. In the position 
indicated at the top of FIG. 2 by means of broken lines delimbed tree 
trunks will be fed out from the delimbing apparatus 3 in parallel with and 
at the side of the machine. 
The position of the delimbing apparatus shown with broken lines 3' at the 
bottom of FIG. 2 is used when lifting trees from positions at the opposite 
side of the machine by means of the lifting crane. Also in this case the 
delimbing apparatus will serve as a counterweight according to what has 
been described above and the delimbed tree trunks will be fed out of the 
delimbing apparatus substantially perpendicularly to the direction of 
length of the vehicle 1. Also in this extreme position the delimbing 
apparatus is of course adjustable to a position suitable for feeding the 
delimbed trunks in parallel with the vehicle 1. 
In the embodiment shown in FIGS. 3 and 4 the shifting of the delimbing 
apparatus 3 laterally is effected by moving the delimbing apparatus along 
a guide 10 which carries the delimbing apparatus and which in its turn is 
carried by an end portion 1b of the chassis 1a of the vehicle 1. The guide 
10 extends substantially perpendicularly to the direction of length of the 
vehicle 1 and is substantially horizontal. The delimbing apparatus can be 
carried and be movable along the guide by means of a carriage 11. The 
movement of the delimbing apparatus along the guide can be effected 
mechanically in various manners, for instance by providing the guide with 
a toothed edge 22 and providing the apparatus at the bottom portion 
thereof with a toothed wheel 21 co-operating with said toothed edge, and 
in such case means can be provided for reversing the direction of rotation 
of the toothed wheel. The guide 10 can extend laterally to and, if 
desired, somewhat beyond the adjacent support wheels of the vehicle 1 at 
both sides. On the guide the delimbing apparatus can be swingable about a 
vertical axis in a similar manner as described in connection with FIGS. 1 
and 2, this making it possible to feed trees to the apparatus from any 
desired direction and to deliver the delimbed trunks at any desired place 
and in any desired direction. Wheel 21 is rotated by a hydraulic motor 
(not shown). 
The embodiment shown in FIG. 5 differs from that according to FIGS. 1 and 4 
mainly in that the delimbing apparatus is carried by a guide which instead 
of being direct mounted on the chassis of the vehicle 1 is mounted at the 
end portion of an arm 4 extending from said chassis. The arm 4 is not 
swingable laterally but is swingably connected to the chassis of the 
vehicle about a substantially horizontal axis extending in the transverse 
direction of the vehicle and is swingable upwards and downwards by means 
of a hydraulic cylinder 23. 
At the connection 24 joining the delimbing apparatus 3 with the supporting 
tap or trunnion 7, which can consist of a housing enclosing a motor, 
suitably a hydraulic motor, for driving the toothed wheel 21 a joint can 
be provided having a horizontal axis extending substantially 
perpendicularly to the direction of feed of the tree trunks through the 
delimbing apparatus. In this case motor means, for instance a hydraulic 
cylinder, can be provided for swinging the delimbing apparatus about said 
horizontal axis so that the apparatus can be set to different inclined 
positions relatively to the ground plane which may be advantageous in many 
cases. 
By the possibility of increasing the stability of the movable machine 
according to the invention lighter vehicles can be used than before, since 
the stability of the complete machine is no longer depending solely on the 
total weight of the machine. This means that the manufacture and the 
operation of the machine requires less material and fuel and the machine 
is more easily movable in a forest stand and does not leave any damage in 
the ground surface, such as those sometimes caused by heavier machines.