DEBARKING SHAFT ARRANGEMENT FOR A DEBARKING MECHANISM

SYSTEME D'ARBRE D'ECORCAGE DESTINE A UN MECANISME D'ECORCAGE

English Abstract

The invention relates to a debarking shaft arrangement for a debarking
mechanism (1), said debarking mechanism (1) being intended for the
decortication or pretreatment of trees (2) for separately performed final
barking and for the expulsion of at least some of the removed barks from a
wood flow passing through the debarking mechanism, said debarking mechanism
comprising a number of rotatable debarking shafts (3) extending parallel to
the advancing direction of the trees (2) to be fed therethrough and provided
with a number of teeth (4) extending beyond the circumferential surface of the
shaft (3) and adapted to strip bark off the presently processed trees (2)
transversely to the lengthwise direction of the trees and at the same to
convey the trees transversely relative to said shafts (3), and said shafts
(3), together with the teeth (4) thereof, being adapted to constitute at least
a part of a support surface, upon which the presently processed trees (2)
travel through the debarking mechanism (1). The teeth (4) are designed to be
effective in both rotating directions of said rotatable debarking shafts (3),
and the debarking shafts (3) are designed to be pivotable.

French Abstract

L'invention concerne un système d'arbre d'écorçage destiné à un mécanisme d'écorçage (1) conçu pour la décortication ou le pré-traitement d'arbres (2) pour l'écorçage final réalisé séparément et pour l'expulsion d'au moins quelques unes des écorces d'un flux de bois passant dans le mécanisme d'écorçage. Ledit mécanisme d'écorçage comporte une pluralité d'arbres d'écorçage rotatifs (3) s'étendant parallèlement au sens d'avancement des arbres (2) devant être traités, ainsi qu'une pluralité de dents (4) s'étendant au-delà de la surface périphérique de l'arbre (3), conçues pour écorcer lesdits arbres (2) perpendiculairement au sens longitudinal des arbres, et convoyer les arbres perpendiculairement auxdits arbres (3). Lesdits arbres (3) et les dents (4) sont conçus pour constituer au moins une partie d'une surface support parcourue par les arbres traités (2) au travers du mécanisme d'écorçage (1). Les dents (4) sont efficaces dans les deux sens de rotation desdits arbres d'écorçage rotatifs (3), et lesdits arbres d'écorçage (3) peuvent pivoter.

Claims

8
Claims
1. A debarking shaft arrangement for a debarking mechanism (1), said
debarking mechanism (1) being intended for the decortication or
pretreatment of trees (2) for separately performed final barking and for the
expulsion of at least some of the removed barks from a wood flow passing
through the debarking mechanism, said debarking mechanism comprising
a number of rotatable debarking shafts (3) extending parallel to an
advancing direction of the trees (2) to be fed therethrough and provided
with a number of teeth (4) extending beyond a circumferential surface of
the shaft (3) and adapted to strip bark off the presently processed trees
(2) transversely to a lengthwise direction of the trees and at the same time
to convey the trees transversely relative to said shafts (3), and said shafts
(3), together with the teeth (4) thereof, being adapted to constitute at least
a part of a support surface, upon which the presently processed trees (2)
travel through the debarking mechanism (1), characterized in that the
teeth (4) are designed to be effective in both rotating directions of said
rotatable debarking shafts (3), and that the debarking shafts (3) are
designed and dimensioned in such a way that a dislodged shaft (3), after
being pivoted through 180 degrees, is mountable in a position from which
it was removed or in place of another debarking shaft (3).
2. An arrangement as set forth in claim 1, characterized in that the teeth
(4) effective in opposite rotating directions of the debarking shaft (3) are
different from each other.
3. An arrangement as set forth in claim 1, characterized in that the
teeth (4) effective in opposite rotating directions of the debarking shaft (3)
are identical to each other.
4. An arrangement as set forth in any one of claims 1 to 3,

7
characterized in that the debarking shaft (3) is attached to the debarking
mechanism (1) in such a way that, in the process of dislodging, the shaft
(3) is liftable from a position and, respectively, in the process of
installation, settable into a position through a wood treating space (5)
present in the debarking mechanism (1).

Description

CA 02438660 2003-08-15
WO 02/083383 PCT/FI02/00122
1
Debarking shaft arrangement for a debarking mechanism
The invention relates to a debarking shaft arrangement for a debarking
mechanism, said debarking mechanism being intended for the decortication
or pretreatment of trees for separately performed final barking and for the
expulsion of at least some of the removed barks from a wood flow passing
through the debarking mechanism, said debarking mechanism comprising a
number of rotatable debarking shafts extending parallel to the advancing
direction of trees to be fed therethrough and provided with a number of
teeth extending beyond the circumferential surface of the shaft and adapted
to strip bark off the presently processed trees transversely to the lengthwise
direction of the trees and at the same to convey the trees transversely
relative to said shafts, and said shafts, together with the teeth thereof,
being
adapted to constitute at least a part of a support surface, upon which the
presently processed trees travel through the debarking mechanism.
The above type of debarking mechanism is prior known for example from US
patents 4,685,498 and 5,394,912.
A problem with the above type of prior known debarking mechanisms is the
inconvenience and high cost of repairing worn or damaged teeth. The teeth
must be repaired one at a time while the debarking shaft remains stationary
in the debarking mechanism.
In order to eliminate these drawbacks, the arrangement according to the
invention in a debarking shaft system for a debarking mechanism is such
that the teeth are designed to be effective in both rotating directions of
said
rotatable debarking shafts, and that the debarking shafts are designed to be
pivotable.

CA 02438660 2003-08-15
WO 02/083383 PCT/FI02/00122
2
This system enables a speedy deployment of new teeth just by pivoting and
securing a shaft at 1800 relative to the original position, whereby it is
parallel
to the original position but has an opposite rotating direction with respect
to
the original position.
The teeth working in the opposite rotating directions of a debarking shaft
can be different from or similar to each other. When using dissimilar teeth in
the opposite rotating directions of a shaft, a different debarking capacity
will
be obtained in various rotating directions, e.g. for wintertime barking and
summertime barking. It is also possible to use sharp teeth first for the
decortication of hard-to-bark or frozen trees, and to use worn teeth for the
treatment of easy-to-bark trees.
In one preferred application of the invention, the arrangement is such that
the debarking shaft is designed and dimensioned in such a way that a
dislodged shaft, after being pivoted through 1800, is mountable in the same
position or in a corresponding position. This arrangement is relevant
primarily when the debarking mechanism is provided with two types of shafts
which are symmetrical in terms of the mounting and axial pitch thereof.
Thus, every other position is always provided with an identical shaft. The
above expression "a corresponding position" should be understood on this
basis.
In particularly preferred embodiments of the invention, the arrangement is
such that the debarking shaft is designed and dimensioned in such a way
that a dislodged shaft, after being pivoted through 1800, is mountable in the
position of an adjacent shaft or in a corresponding position. The expression
"a corresponding position" refers to those alternating positions for a
debarking shaft in which the shafts lie co-directionally. This arrangement is
applicable when all debarking shafts in a debarking mechanism are identical
to each other. This arrangement offers the advantage that the debarking

CA 02438660 2006-03-29
3
mechanism only requires a single type of spare shaft that is hence fit for
all positions. In principle, such a shaft could be secured in the same
position in each of its pivoted positions, but this would require e,g,
different attachment points for different shaft pivoting directions.
In yet another preferred embodiment of the invention, the arrangement is
such that the attachment of a debarking shaft to a debarking mechanism
is impiemented in such a way that, in the process of dislodging, the shaft
is liftable from its position and, respectiveiy, in the process of
installation,
settable into its position through a wood handling facility.
According to a first aspect of the invention, there is provided a debarking
shaft arrangement for a debarking mechanism (1), said debarking
mechanism (1) being intended for the decortication or pretreatment of
trees (2) for separately performed final barking and for the expuision of at
least some of the removed barks from a wood flow passing through the
debarking mecchanism, said debarking mechanism Comprising a number
of rotatable debarking shafts (3) extending parallel to an advancing
direc#ion of the trees (2) to be fed therethrough and provided with a
number of teeth (4) extending beyond a circumferentiai surface of the
shaft (3) and adapted to strip bark off the presentiy processed trees (2)
transversely to a lengthwise direction of the trees and at the same time to
convey the trees transversely relative to said shafts (3), and said shafts
(3), together with the teeth (4) thereof, being adapted to constitute at least
a part of a support surface, upon which the presently processed trees (2)
travel through the debarking mechanism (1), characterized in that the
teeth (4) are designed to be effective in both rotating directions of said
rotatable debarking shafts (3), and that the debarking shafts (3) are
designed and dimensioned in such a way that a dislodged shaft (3), after
being pivoted through 180 degrees, is mountable in a position from which
it was removed or in place of another debarking shaft (3).

CA 02438660 2006-03-14
3A
An exemplary embodiment of the present invention will now be described
in more detail with reference to the accompanying drawings, in which:
FIG. 1 shows debarking shafts for a debarking mechanism of the
invention, in a schematic side view.
FIG, 2 shows a section along line II--II in fig. 1.
FIG. 3 shows a section along line IIi--III in fig. 2.
A debarking mechanism I depicted in the drawings is intended for the
decortication or pretreatment of trees 2 for separately performed final
barking and for the expulsion of at least some of the removed barks from
a wood flow passing through the debarking mechanism.
The debarking mechanism I is provided with a number of rotatable
debarking shafts 3 extending parallel to the advancing direction of the
trees 2 to be fed therethrough. In the iNustrated example, the debarking
shafts 3 have each end thereof provided with sprockets 6, whereby, at
least at one end of the debarking mechanism 1, the sprockets 6 are by
way of a sprocket

CA 02438660 2003-08-15
WO 02/083383 PCT/FI02/00122
4
chain (not shown) to each other and to the gear of an electric motor, not
shown.
The debarking shafts 3 are provided with a number of teeth 4 extending
beyond the circumferential surface of the shaft 3 and adapted to strip bark
off the presently processed trees 2 transversely to the longitudinal direction
of the trees and at same time to convey the trees transversely relative to the
debarking shafts 3.
The debarking shafts 3, together with the teeth 4 thereof, constitute a part
of a support surface for carrying the trees 2 through the debarking
mechanism 1. The illustrated example includes four debarking shafts 3 which
are assembled relative to each other to define an inclined plane. Other than
that, the support surfaces comprise solid surfaces which are designed for
providing, together with the support surface constituted by the debarking
shafts, an open-ended chute covering the debarking mechanism 1 from end
to end. The chute can be open-topped or covered.
The teeth 4 carried by the debarking shafts 3 are designed to be effective in
both rotating directions of the debarking shafts 3. However, in the debarking
mechanism 1, the debarking shafts 3 are all rotating always in the same
direction as indicated by an arrow 7 (fig. 2). The teeth 4 effective in
various
directions can nevertheless be exploited when the debarking shafts 3 are
designed to be pivotable.
In the solution of fig. 1, all four debarking shafts 3 are designed to be
identical to each other. However, the teeth set at regular spaces along the
circumference of the debarking shaft 3 are positioned asymmetrically in the
lengthwise direction of the shaft 3, an intermeshing for the teeth 4 of the
adjacent shafts 3 being accomplished by installing the adjacent shafts 3 in
opposite directions, i.e. reversed by 1800.

CA 02438660 2003-08-15
WO 02/083383 PCT/FI02/00122
The teeth 4 effective in opposite rotating directions of the debarking shaft 3
can be different from or similar to each other. This arrangement enables a
speedy deployment of new teeth just by pivoting and securing a shaft at
1800 relative to the original position, whereby it is parallel to the original
5 position but has an opposite rotating direction with respect to the original
position. For example, the topmost shaft in fig. 1 in a reversed condition can
be substituted either for the shaft second from top or for the lowermost
shaft.
The debarking shafts 3 have each end thereof provided with smaller-
diameter shaft stubs 8, on which are mounted bearings, along with bearing
cups 9 therefor, as well as the sprockets 6. The bearing cups 9 are adapted
to be secured with screws 11 to end panels 10 present at the ends of the
debarking mechanism 1 in line with the debarking shafts 3.
The debarking shaft 3 has its attachment to the debarking mechanism 1
implemented in such a way that, in the process of dislodging, the shaft 3 is
liftable from its position and, respectively, in the process of installation,
settable into its position through a wood treating space 5 present in the
debarking mechanism 1. In the illustrated example, this is implemented in
such a way that the end panels 10 have a top edge thereof provided with
open-topped grooves 12 for the shaft stubs 8 of the debarking shafts 3.

Representative Drawing