Note: Descriptions are shown in the official language in which they were submitted.
1335169
The present invention relates to a debarking drum for
debarking timber, and in particular a dry debarking drum in
the form of a hollow cylinder, preferably with a shell
essentially consisting of metal.
The shell is provided with orifices or slots for discharging
the bark material, conveniently a solid sheet steel shell, in
particular having a horizontal or essentially horizontal axis
of rotation, both front faces of the drum conveniently being
open or essentially open. Catches or projections, preferably
lo rods or the like, in particular lifting rods or lifting
irons, are provided on the inner shell of the drum directed
towards its interior and preferably evenly distributed over
the drum circumference and conveniently extending parallel to
the drum axis. The catches or projections or rods consist of
elastic material or elastomers, conveniently of rubber,
mechanically resistant materials with surfaces coated
therewith, conveniently metal, in particular aluminum or
steel, or uncoated metal, conveniently steel or aluminum.
The drum is conveniently supported on the outside on wear-
proof, in particular hard metal rolls, on rings or rolls orpacks of rings or rolls, conveniently with steel inserts,
conveniently coated with rubber, polyurethane or the like or
consisting of hard rubber or plastics material, or on car
tires or the like, via which the drum can be driven by means
of friction generated by an electric motor, conveniently at
an adjustable speed.
The drum can also be supported on hydrostatic bearing units.
In the case of hard or hydrostatically supported drums, the
drive is conveniently positive, i.e not by friction. Not
only electric motors, but also hydraulic drives are suitable.
26a~ f
A ~ Tt 13 an objcct of th~-invention to roduco loss of timber and
noise and vibration emissions in debarking devices of this
type and at the same time achieve a substantial increase in
the debarking output.
J~ ~
1335169
The invention is based on debarking drums with a solid drum
shell and projections provided on the inside of this shell
such as are known, for instance, from AT-PS 130,037 and
348,246.
~5 ~ The ~j~ct of th~ invention is achieved by starting out from
debarking drums, in particular dry debarking drums, in the
form of hollow cylinders.
According to the invention, the problem is solved by
providing, in particular for debarking short timber, a
zone(s) provided with catches, projections, lifting rods or
the like to alternate with a zone(s) free of catches,
projections, lifting rods or the like, viewed in axial
direction on the inner shell of the drum, or providing that
the inner shell zone provided with catches, projections or
lifting rods or the like is interrupted, viewed in axial
direction, by at least one area free of catches, projections,
lifting rods or the like, the inner zone(s) or the inner
shell area(s) or this sliding surface or sliding layer
conveniently being coated with low-friction material, for
instance smooth plastics material plates or composite
material consisting on its surface or sliding layer of
plastics materials such as polyethylene and underneath this
of a damping or supporting layer of elastomers, such as
rubber, or a layer lined therewith. Since the zones
containing catches, projections, lifting rods or the like are
interrupted by zones not containing any such lifting rods or
the like, the result is an additional relative movement of
the logs to be debarked, which permits a substantial increase
of the debarking output as compared to known embodiments
comprising lifting rods extending over the entire length of
the drum.
The additional relative movement constitutes additional
friction of the logs rubbing against one another. A zone-
wise interruption of the inner shell equipment of catches,
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lifting rods or the like, for instance over a longitudinal
extension of one to five log lengths, results in a
disorientation of the bulk of logs and thus in an increased
relative movement of the material to be debarked. This
results in an increased share of friction work as compared to
embodiments having uninterrupted zones equipped with lifting
rods or the like and thus in an increased debarking output.
It may be convenient if the length of zones or areas provided
with in particular straight lifting rods or the like is of
approximately the same length as the length of zones free of
lifting rods or the like. The front face zones of the drum
can be free of lifting rods.
For the operation of the debarking drum according to the
invention, it may be particularly convenient if the lifting
rods or the like extending over only a part of the length of
the drum consist of rubber or any other elastic material such
as hollow rubber rods, conveniently of approximately
triangular or approximately semicircular cross section, with
a supporting core made of metal, conveniently of steel, for
obtaining a releasable connection with the inner shell of the
drum, this connection being provided in the area of the basis
of the triangle or in the area of the semicircle diameter and
between these rubber rod areas, viewed in axial direction,
the rodless inner wall zones, consisting of metal, to be
provided with an elastomer, conveniently rubber layer with
the surface of which facing the interior of the drum a
polyethylene layer or the like is connected abrasion-proof.
In this way, the noise and vibration emissions can be
considerably reduced, the low-friction or smooth material in
the form of polyethylene-rubber composite material for the
zone(s) free of lifting rods playing an essential part in
this effect. Moreover, loss of timber is reduced.
The invention will now be described in more detail, by way of
example only, with reference to the accompanying drawings in
- 13351G9
which:-
Figs. 1 and lA are diagrammatic representations of a
debarking drum according to the present invention, in
particular in the longitudinal section along plane A-B in
Fig. 2 and 2A, partially in elevational view;
Fig. 2 and 2A show diagrammatic cross sections along plane
C-D of Fig. 1 and lA; and
Figs. 3 and 4 show details thereof, namely Fig. 3 shows a
cross-sectional view of the drum wall in the area of the
lifting rods and Fig. 4 shows a cross-sectional view in the
area of a rodless zone.
Drum drives are sketched in Figs. lA and 2A.
In all the figures, like parts are designated by identical
reference symbols.
The debarking drum 1 in the form of a hollow cylinder, in
particular dry debarking drum, in the present case consists
essentially of metal, conveniently steel. The drum axis 2
extends horizontally. The front faces 3 of the drum are
essentially open. They may be partially closed adjacent the
outer shell by means of a ring. Viewed in axial direction,
zones 6 provided with lifting rods 4 alternate with rodless
zones 6. As shown in Fig. 4, the inside of the metal or
steel shell 7 is provided with a rubber coating 8 which is in
turn lined with polyethylene g on the inside.
The lifting rods 4 are conveniently evenly distributed in
their individual zones 6 over the circumference of the drum
and thus at equal distance from one another. As indicated in
Fig. 3, the lifting rods essentially consist of elastomers,
in particular rubber 10. In the embodiment shown, it is a a
metal, for instance steel, core 11, by means of which the
rods are connected, in particular releasably, to the shell 7
of the drum, via anchorages, for instance anchor bolts, a
rail 12 or the like.
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Between the rods, there are slots or discharge openings 13 in
the drum. The rods can also consist entirely of elastomers,
such as rubber, and be firmly connected to the inner shell of
the drum in any other form. Other elastic materials, such as
elastic plastics materials, are also suitable materials for
the rods.
As evident from Fig. lA and 2A, the drum is supported on the
outside of its circumference on wear-proof, in particular
hard metal rolls, on rings 14 or rolls coated with
lo elastomers, for instance rubber, polyurethane and the like or
consisting of hard rubber or plastics material, by supporting
it for instance in rockers 16. The drive of the rings and
thus the rotation of the debarking drum, which is in
frictional engagement with the rings, is effected by an
electric motor 16 whose speed is conveniently variable.
As initially mentioned, the drum could also be supported on
rings or rolls or packs of rings or rolls, conveniently with
steel inserts, or on car tires or the like, via which the
drum can be driven by friction from an electric motor,
conveniently with variable speed.
It is also possible to support the drum on hydrostatic
bearing units. In the case of drums which are supported hard
or hydrostatically, the drive is conveniently positive, thus
not by means of friction. Not only electric motors, but also
hydraulic drives may be used.
It is important to provide the rodless zone 6 on the inside
of the drum with a low-friction or smooth material causing
the aforementioned disorientation of the bulk of logs. An
increased relative movement of the logs towards and away from
one another is the result and increases the debarking output.
The low-friction lining shown in Fig. 4 consists of composite
material with a surface layer of polyethylene 9 or the like
1335169
firmly connected to a rubber basis 8. Other smooth plastics
material plates can also be used.
The rodless zone(s) can have individual axial length(s) of
one to five times the length of the logs to be barked. In
this present case, these zones 6 have an axial length of one
to five logs. One or more zone(s) 6 is (are) provided. It
would be conceivable to make the zones 6 and 6 of equal
lengths. In the instant case, both front face zones are
provided with lifting rods, reference is made to Fig. lA in
this context. But it may be more convenient to leave the
zones on the front faces free of lifting rods.
As evident form Fig. 3, the cross-sectional shape of the
lifting rods 4 can be approximately triangular. Semicircular
cross sections are also suitable. If the connection to the
inner shell of the drum is releasable, a replacement of the
worn lifting rods is easier, which is of particular advantage
when using rubber as the lifting rod material. Under certain
circumstances, curved lifting rods or lifting rods in the
form of conveyor cams or conveyor nubs could also be used.
The debarking drums according to the invention are
particularly valuable for short timber of lengths up to 0.6
times the drum diameter.
The openings or slots for discharging the bark material can
extend horizontally, parallel to the axis or obliquely.
Suitable drums are for instance those of a diameter of 3.6 to
6.6 meters , a length of 8 to 50 meters and rotation speeds
of 3 to 5 rpm. Low-friction, smooth materials other than
polyethylene, in particular plastics materials, or the
uncoated or blank basic material of the drum (steel) are
suitable for the inner surface of the rodless zones.
According to the invention, the interruption of the lifting
rods, lifting irons or catches brings about a considerable
1335169
reduction of the loss of timber and of the noise and
vibration emissions at increased machine output and debarking
output. The timber or bulk filling in operation is indicated
with the reference symbol F and a hatching in Fig. 1, lA and
2, 2A. The debarking effect extends virtually over the
entire bulk cross section.
