Note: Descriptions are shown in the official language in which they were submitted.
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Needling machine and a method for the operation thereof
Description
The invention relates to a needling machine and to a method of operating a
needling machine in accordance with the preambles of patent claims 1, 2 and 7.
Needling machines of the kind in question here are known and are used in the
field
of needled non-woven bonding, such needling machines also being used, for
example, in the production of paper-maker's felts. The needling machines have
needle boards with special needle spacings that have specific repeats. A
common
feature of the needle spacings is that there are specific forward feed regions
which
are revealed in millimetres forward feed of the felt per needle board stroke
and
which produce marks, generally undesirable marks, on the felt surface, which
are
unacceptable for demanding applications of the felt, such as, for example, on
a
paper-making machine.
Furthermore, during needling, visible repeats are formed on the felt surface
which
are caused by a natural contraction in width during needling.
Such repeats produce unattractive patterns or artefacts on the treated felts
which
are undesirable and, when the felts are used in paper-making machines, show up
in the paper produced.
That disadvantage is inherent to conventional needling machines and it is
extremely difficult, if not impossible, to obtain a textile surface appearance
that is
uniform over the entire felt. In the past, in the attempt to impart a uniform
surface
appearance to the felt produced, recourse has been taken to an irregular
distribution of the needles on the surface of the needle board, but such a non-
uniform distribution aiways constitutes a compromise and gives a result that
is still
unsatisfactory for many applications.
Conversely, with the needling machines customary hitherto, it is also not
possible,
however, deliberately to produce a specific repeat, a certain pattern or a
certain
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structuring in a felt, because in that case too the repeats inherently
produced by a
needling machine are troublesome.
The aim of the invention is to solve the problems described above and to
provide a
needling machine by means of which it is possible to produce a felt without
repeats
or with desired repeats on the surface of a textile and/or on the surface of a
felt.
That aim is achieved by a needling machine in accordance with patent claims 1
and 2 and by a method in accordance with patent claim 7.
The aim is achieved, especially, by a needling machine, especially for use in
the
production of paper-maker's felts, the needling machine having at least one
roller,
configured as a traversing roller, which is movable, preferably back and
forth, in the
axial direction during operation, by means of which roller the product being
needled
is movable transversely with respect to the needling direction, that is to say
in the
axial direction, in accordance with the movement of the traversing roller.
Furthermore, the aim is achieved by a needling machine, especially for use in
the
production of paper-maker's felts, the needling machine having at least one
spreading device which is movable back and forth in the axial direction and by
means of which the product being needled is movable transversely with respect
to
the needling direction, that is to say in the axial direction, in accordance
with the
movement of the spreading device.
An important aspect of the invention is that by virtue of a specific lateral
displace-
ment of the needle insertion points, in a felt or some other textile fabric,
the
distribution of the insertions can be rendered uniform. That effect is
independent of
any needle spacing used. Accordingly, in accordance with the invention it is
possible, by means of a roller that is moved back and forth, to avoid
unintentional
repeats or, by means of specifically controlled axial displacement of one or
more
rollers in the needling machine, specifically to produce repeats, patterns or
irregularities in the textile fabric being processed, such as, for example, a
felt.
It is also possible by means of this technology to prevent or, as desired,
specifically
to increase the formation of "needling alleys", namely repeat-like marks on
the
needled textile surface.
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According to the invention, at least one driven or co-running roller is moved
back
and forth, that is to say in a traversing movement, transversely with respect
to the
forward feed movement, that is to say in the axial direction of the roller in
question.
According to how many and which rollers of a needling machine are moved, it is
possible to obtain different results in respect of a repeat or pattern. It
should be
stressed at this point that in the case of a plurality of traversing rollers,
their
movement can be in the same direction or in opposite directions. Furthermore,
the
stroke and the stroke frequency can be adjusted, preferably steplessly,
individually
for each roller.
In accordance with an embodiment of the invention, the stroke of the
traversing
roller and/or the spreading device is from 0 mm to 15 mm, preferably from 0 mm
to
12 mm and especially from 0 mm to 10 mm. A larger stroke of up to three times
the
indicated value as well as an especially small stroke range of 1.5 mm is
conceivable, depending upon the use and the pattern to be achieved.
Furthermore, the stroke of the traversing roller and/or spreading device is
steplessly adjustable and can optionally be altered during operation.
According to the invention, the stroke frequency is in the region of from 1 to
120
strokes per minute, it being stressed that the movement of the traversing
roller
and/or spreading device proceeds continuously in the axial direction. In the
same
way as the stroke length of the traversing roller and/or spreading device, the
stroke
frequency thereof is also steplessly adjustable.
The drive for a stroke movement of the at least one traversing roller and/or
spreading device is effected, alternatively or in combination, mechanically,
hydraulically, electrically, magnetically and/or pneumatically, it being
stressed that,
depending on the stroke frequency and stroke length as well as the size and
weight
of the roller and/or spreading device, different driving can be provided. It
should be
stressed at this point that the spreading device can be in the form of a
roller or in
the form of a roller combination, especially of 3 to 5 rollers.
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It is also possible to implement a traversing movement of the textile fabric
with the
aid of an additional roller pair between the needling machine and a tensioning
carriage on a felt-inlet and/or felt-outlet side. It is furthermore possible
for the
spreader used in the needling machine, i.e. the above-mentioned spreading
device, to be configured as a traversing unit transverse to the direction of
travei of
the felt. It shouid be stressed at this point that in the context of this
invention a roller
can also be implemented as a region that is movable back and forth, over which
the textile fabric being processed merely slides, without that region
performing a
rotational movement.
In respect of possible drive methods for the stroke movement of a roller, a
roller
pair or a spreader, transverse to the direction of travel of the felt, the
possible
methods mentioned below are provided in accordance with the invention. A
mechanical drive by means of a drive rod, such as, for example, a crank drive,
an
eccentric drive, a cam plate or swash plate or like mechanical drives.
Hydraulic
drives, for example by means of hydraulic cylinders or a hydraulic motor, are
also
provided. Moreover, the stroke movement can be provided electrically by means
of
an electric motor with gears or with a spindle. The same applies to a
pneumatic
drive with the aid of a pneumatic cylinder or motor with the aid of a gear or
a
spindle.
The aim of the invention is also achieved by a method of operating a needling
machine, especially for the production of paper-maker's felts, wherein at
least one
roller of the needling machine is moved in the axial direction, preferably
back and
forth, during operation. The movement of the roller is effected according to
the
invention with a stroke of from 0 mm to 15 mm, preferably from 0 mm to 12 mm,
and especially from 0 mm to 10 mm, the stroke of the roller, especially in
operation,
being steplessly adjusted and/or re-adjusted.
Further embodiments of the invention will be found in the subsidiary claims.
The invention is described below on the basis of an exemplary embodiment which
is explained in greater detail with reference to the Figures.
Fig. 1 is a diagrammatic view of a needling machine;
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Fig. 2 is a diagrammatic view of a traversing roller with a drive unit for a
stroke
movement;
Fig. 3 is a diagrammatic view of a detail of the traversing roller with a
drive unit
from Fig. 2.
Fig. 1 shows a diagrammatic view of a needling machine, wherein the roller
indicated by reference letter A is the drive roller of the system. The rollers
indicated
by reference letter D are guide rollers by means of which the textile fabric
being
transported and needled is moved on the one hand and held taut on the other
hand. The devices indicated by reference letter Z are the respective needling
zones
of the needling machine, a spreader for the textile fabric, indicated by
reference
letter B, being shown diagrammatically in the upper region of the Figure. In
the
lower region of the Figure there is an external traversing unit indicated by
reference
letter C. The textile fabric, especially a felt, is supplied from the rolls
shown, their
material being moved anti-clockwise in a needling machine. According to the
invention, it is possible to operate one or more of the rollers A, B, C and D
in
traversing mode.
Fig. 2 shows a traversing roller, the stroke of which in the axial direction
is indicated
by a double-headed arrow and labelled with 0-X, with 0-X being the stroke
length of
the traversing roller.
As shown on an enlarged scale in Fig. 3, the traversing roller is moved in a
traversing movement from left to right and back again by means of a crank
drive.
It should be pointed out here that all the above-described parts, alone and in
any
combination, especially the details shown in the drawings, are claimed as
being
important to the invention. Modifications thereof will be known to the person
skilled
in the art.
