Note: Descriptions are shown in the official language in which they were submitted.
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18147
C~ 1NUO~S PRESS FOR THE PRODUCTION OF PARTICLE BOARD
AND T.AMTN~'I'ES
SPECIFICATION
Field of the Invention
The present invention relates to a continuous press for the
production of particle board, especially chip board or fiber board
utilizing wood or cellulosic materials and thermally-activatable
binders, or laminate plates (more generally referred to as laminates
herein) or the like, wherein the material to be pressed is fed
between a pair of endless steel belts, passing over guide rollers
which can be driven, through a zone of the press in which the
material is compressed and, if desired or necessary, is heated.
Bac~4~ of the Invention
In conventional continuously-operating presses of this type,
the guide drums, which also are generally the drive drums of the
press, can be composed of a steel structure in which a steel plate
or sheet define~ the ou.er surface of the drum which can be formed
with a friction lining to better engage the steel belt which passes
around the drum. The closed shell of the drum thus supports, guides
and drives the belt.
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Prior art techniques for applying the friction lining to the
drum have been found to be expensive and frequently unreliable
since it is often necessary to machine the lining on the drum to
be certain that the drum will be sufficiently cylindrical. A
true cylindrical configuration or a substantially cylindrical
configuration of predetermined configuration is essential so that
the steel belt will not shift off the drum in operation.
Various friction linings have been used for this purpose and
one must be concerned with respect to the friction coefficient.
If the friction coefficient is not sufficient, slippage between
the steel belt and the drum is unavoidable so that the service
life of the lining and the availability of the continuous press,
measured by down time for replacement and maintenance, can be
detrimentally affected. In general it is not practical or
possible to provide a form-fitting engagement between the guide
drum and the steel belt for positive entrainment of the latter
and hence friction coupling between the belt and the steel drum
is a necessity.
It is the principal object of the present disclosure to
provide a continuously-operating press for the purposes described
which will have increased service life of the friction coupling
between the drum and the belt and thus increase the availability
of the press.
It is another object to provide a particle board or laminate
press whereby drawbacks of other continuously operating presses
are avoided.
It is especially an object to provide an improved friction
coupling between a steel belt and a guide drum in a continuous
press for the production of pressed board and laminates.
These objects and others which will become apparent
hereinafter are attained, by providing the friction coupling
between the drum and the steel bond or belt of a continuous press
with friction plates in a tile-like array on the surface of the
supporting drum, each of the friction plates comprising an outer
friction lining or overlay and being affixed to a support plate
which is attached to the surface of the drum and can have a
curvature corresponding thereto. Like tiling, each of these
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friction plates can adjoin other friction plates on the surface
of the drum in butt joints of a minimum gap width and which can
permit slight expansion and contraction or afford direct contact
between the adjoining edges as required.
The lining or overlay can be a commercial material of the
type commonly used for clutch linings and/or brake linings
heretofore and preferably for motor vehicle clutch or brake
linings.
More specifically, in a continuous press for the production
of pressed board and laminates and wherein material to be pressed
is advanced through the press between a pair of steel belts
passing over guide drums, here, described is an improvement
wherein at least one of the guide drums is formed with a drum
support having a substantially cylindrical outer surface, a tile
array of friction plates covering the surface,and means for
affixing the friction plates to the support at the surface,
adjacent ones of the friction plates of the tile array having
substantially butt joints of small gap thickness and each being
formed with a support plate and a friction lining selected from
the group which consists of standard
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18147
clutch and brake linings secured to the support plate and defining
with the friction linings of the other friction plates of the array
a substantially cylindrical belt-engaging layer.
I have found surprisingly, that commercial material, which
s have been employed in modern technology as clutch linings and brake
linings, can satisfy all of the requirements for a frictional
interengagement between the steel belt and t~.t? .~uid~ drllm ln ~
continuous press for the production of chip bo~rd, fiber board,
laminated boards and the li~e, when this mat~rial is used in a
lining on a support plate to form a friction plllte mounted on the
drum of the press in a tile array. This is especially the case when
the lining material is a motor vehicle brake or clutch lining.
A detrimental slip between the guide drum and the steel belt
which passes therearound is no lon~ler a problem. Friction coeffi-
cients of 0.4 and greater can b~ used. The fact that there are gaps
or butt joints between the friction plates arranged in the tile
array also is not found to be detri~ental but rather, quite
surprisingly, is found to increase the overall friction coupling
between the drum and the belt.
of course, the friction plates must follow the curvature of
the surface of the drum and must be correspondingly curved. The
joints whiCh are formed can be perpendicular to the drum surface and
can extend along generatrices and circumferences of the drum.
The linings which are composed of commercially-available
clutch lining or brake lining materials are readily capable of
withst~nding the temperatures which arise in continuous presses for
the production of chip board, fiber board, laminate plates and the
like. This applies whether the drums are heated or nonheated.
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The linings are also sufficiently oil resistant. The
fastening of the friction plates on the drum surface and the
function thereof are not adversely influenced by thermal
expansion and contraction. The friction plates may be secured
S to the surface with prestress or with bracing against one another
as desired. Tests have shown that continuous presses provided
with the new tile arrays provide extremely long service lives of
the friction material and thus improved availability of the press
as a whole.
According to a feature of this disclosure, the support plate
for the friction plate of the invention is a steel plate whose
thickness can be about 4 mm for a standard continuous press for
the purposes described.
Various materials commonly used for brake shoes and clutch
plates as linings in the motor vehicle industry may be employed
and, in general, I may make use of materials based upon synthetic
resin or synthetic rubber binders and containing wear-resistant
fillers. Alternatively, the lining can be of ceramic material.
For standard laminating of the pressed board presses, the lining
thickness should be about 8 mm.
In a continuous press here described, the drive torque which
is to be applied to the steel belts is delivered by the drum
through the friction lining to the belt. It is thus important
that there be a sufficiently shear-resistant connection of the
lining to the support plate of the friction plate. This can be
achieved, in accordance with a further feature by providing an
adhesive bond between each lining and the respective support
plate.
The drum shell is also composed of steel and it is essential
that the connection between the friction plates and the steel
shell be capable of withstanding the aforedescribed torque. For
this purpose the means connecting the friction plate to the shell
may include a screw connection or an equivalent thereto such as
a rivet connection.
The friction plates, which are precurved to conform to the
curvature of the drum, can be mounted and dismounted in a simple
manner.
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In general, the plates can be rectangular, a special case
of which is a square plate.
The linings can also play a thermodyanmic role. For
example, in the case of a heated guide drum, the lining may
contain a metallic filler to provide a high conductivity path
between the drum and the belt. In the case in which the drum is
unheated,the filler in the friction lining may be a thermally
nonconductive filler so that the lining plays a heat-lagging or
insulating role between the drum and the steel belt. The running
of the steel belt can thus be positively influenced.
More particularly in accordance with the invention there is
provided, in a continuous press for the production of pressed
board and laminates and wherein material to be pressed is
advanced through the press between a pair of steel belts passing
over guide drums, the improvement wherein at least one of said
guide drums is formed with a drum support having a substantially
cylindrical outer surface, a tile array of friction, plates
covering said surface, each of said friction plates being of
generally rectangular configuration and elongated fastening means
for affixing said friction plates to said support at said
surface, adjacent ones of said friction plates of said tile array
having substantially butt joints of small gap thickness and each
being formed with a support plate and a friction lining selected
from the group which consists of standard clutch and brake
linings secured to said support plate and defining with the
friction linings of the other friction plates of said array a
substantially cylindrical belt-engaging layer.
Embodiments of the invention will now be described,
reference being made to the accompanying drawings in which:
FIG. l is a diagrammatic partial side elevational view of
a continuous press for the production of chip board, fiber board,
laminate plates or the like;
FIG. 2 is an elevational view of a guide drum of the press
of FIG. l but shown to a larger scale and partly broken away;
FIG. 3 is a plan view of a friction plate which can applied
to that drum, shown greatly enlarged in scale with respect to
FIG. 2;
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FIG. 4 is a cross sectional view taken along the line IV-IV
of FIG. 3; and
FIG. 5 is a section taken along the line V-V of FIG. 3 but
additionally illustrating the plate in place upon the drum and
diametrically showing it to be engaged by the steel belt.
Description of the Preferred Embodiments
As can be seen from FIG. 1, a continuous press for the
production of chip board, fiber board, laminate plates, and the
like, can comprise a plurality of guide and drive drums 2, only
two of which have been illustrated in the drawing, around which
steel belts 3 pass, the steel belts defining a pressing gap 3a
between them, through which the material 4 is pressed and is fed
for compaction. The press also can comprise platens 20 and 21
which can be heated, e.g. with circulating steam, and which can,
if desired, inject steam into the material 4 through perforations
in the belts 3, if desired.
Advantageously, continuous presses of this type are well
known in the art of the manufacture of pressed board and as
laminating presses and will not be described in greater detail
herein. Suffice it to say that a drum 2 can have a friction
surface represented generally at 5 so that each drum can
frictionally entrain the respective belt 3 to drive the latter
as represented by the arrows 22, 23, 24 and 25 in FIG. 1.
From FIG. 2 it will be apparent that the drum 2 can comprise
a support shell 26 mounted on a shaft 27 and formed with a
surface 10 upon which the friction material 5 is provided.
From FIG. 2 it is also apparent that the friction material
5 is formed by a multiplicity of friction plates 6 which are
shown to be of rectangular configuration and can be curved to
conform to the contours of the surface 10 (FIG. 4) and which are
disposed in a tile array so that butt joints 7 of narrow gap
width are formed between the friction plates which completely
cover the surface 10.
From FIG. 2 it is apparent that these joints are aligned at
7a along generatrices and at 7_ along circumferences of the drum.
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FIGS. 3-5 show that each friction plate 6 or tile of the
drum is comprised, in turn, of a support plate 8 and a covering
or overlay 9 which can be bonded thereto by an adhesive layer 17
(FIG. 5). To further resist shear, the covering 9 may be molded
around the support plate 8 at 18 so as to flank the edges of the
support plate and define the flanks 29 which form the joints 7.
these flanks 29 constitute abutment edges 11 which extend
perpendicular to the surface 10 of the drum. In addition, and
also to resist shear, the plate 8 may be perforated so as to have
holes 30 into which protuberances 31 of the overlay 9 can extend.
The plates 8 are composed of steel and the overlay 9 can be
a commercial material utilized as a clutch lining and/or brake
lining, preferably a lining material for an automotive vehicle
clutch plate and/or brake shoe.
The friction plates 6 follow the geometry of the shell 26
of the drum 2 as is apparent from the curvature of the plate 6
shown in FIG. 4.
Comparison of FIGS. 4 and 5 will further show that the gap
7 between adjoining plates may provide a slight clearance so that
the edges 11 will abut only at the elevated temperature at which
the drum operates. At lower temperatures there can be a slight
clearance of say a fraction of a mm.
The adjoining friction plates may, however, be in contact
at their edges at all times.
The steel plates 8 can have a thickness of about 4 mm. The
lining 9 can have a basis or matrix of synthetic resin or
synthetic rubber and can contain a wear-resistant filler.
Alternatively, the lining 9 can be of ceramic brake lining
material. Its thickness can be about 8 mm.
As shown in the drawing,the friction plates 8 have an
elongated rectangular outline. However, they can be square.
They can be mounted with a predetermined prestress on the drum
shell and surface 10 or can be braced against one another as
already noted. For heated drums 1, the overlay 9 can contain a
metallic filler so as to have a high thermal conductivity. For
unheated drums 2, it is advantageous, to utilize a filler of low
thermal conductivity in the drum. Fillers of low thermal
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conductivity can include silica particles while metal particles
of high thermal conductivity can be composed of copper. The
usual fillers for automotive brake linings and clutch linings may
be incorporated in the overlay 9 otherwise. In the embodiment
illustrated in FIGS. 2-4, the plates 6 can be secured utilizing
a screw as represented, for example, by way of the screw head 33
shown in Fig. 3.
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18147
In a best mode embodiment, however, the plates 6 are secured
to the shell 26 of the drum 2 by fastening assemblies 12 and 13
which can include bushings 12 and blind rivets or pins 13 passing
through the bushing 12 and braced against washers 34. The bushings
12 are snugly received in the bores 35 of the drum 2 and act as
force-transmitting members. With the friction surface 5 formed by
the friction tiles 6, it is found that the friction surface has an
extremely high service life and thus that the press incorporating
same has a correspondingly long operating duration without down
time.
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