Note: Descriptions are shown in the official language in which they were submitted.
CA 02772658 2012-02-29
1
DEVICE AND METHOD FOR PROCESSING ELONGATE WORKPIECES
WITHOUT CUTTING
The invention relates to a device for processing elongate
workpieces without cutting to produce a thread-like outer
profile by means of at least one shaping roller arrangement
having at least two shaping rollers that can be rotated about
respective axes, wherein the shaping roller arrangement
surrounds the workpiece to be processed, wherein a feed motion
between the shaping rollers and the workpiece is established
in the circumferential direction of the workpiece and axially
to the workpiece, and wherein the shaping rollers are
successively brought into a shaping engagement with the
workpiece during a complete revolution around the workpiece,
and a method for processing elongate workpieces without
cutting to produce a thread-like outer profile by means of at
least one such device, in which the workpiece to be processed
is processed in its circumferential direction and axially by a
feed motion into a roller head, wherein the shaping rollers
are successively brought into a shaping engagement with the
workpiece during a complete revolution around the workpiece.
The substantially continuous production of rock bolts, drill
rods and other comparable products, departing from bar-shaped
or tubular base bodies, by processing without cutting in a
rolling process is, for instance, described in the document DE
43 13 918 A. The shaping tool used in that device comprises a
roller head in which three shaping rollers profiled in their
peripheral regions are mounted, whose axes extend at a
respective angle to the axis of the base body to be externally
shaped in a thread-like manner, while being uniformly
distributed about the same. To perform the shaping process,
the roller head is driven around its axis, which extends
CA 02772658 2012-02-29
2
coaxially with the axis of the base body, such that the axial
advance of the base body, which is held rotationally fast
about its axis, will result from the angular adjustment of the
shaping rollers.
The document DE 101 10 569 Al describes a comparable device,
which uses a roller head that - viewed in the passing
direction - includes several arrangements each comprised of at
least three shaping rollers whose profiles differ from one
another and which are adapted to the shaping process
proceeding in said direction. Each of the shaping rollers has
a ring-shaped, pitchless outer profile, wherein, by an angular
adjustment relative to the axis of the non-rotationally held
workpiece, an axial advance is made as a function of the
rotation of the roller head about its central axis, which
extends coaxially with the axis of the workpiece.
In the document DE 10 2007 029 548 B3, a roller head for use
in such a device and, in particular, the mounting of the
shaping rollers, are described. The roller head is comprised
of an assembly of several axially spaced-apart bearing discs,
which is rotationally mounted about a central axis and
connected to a drive and between which discs an assembly of
shaping rollers is each provided. The shaping rollers are
mounted so as to be freely rotatable about their respective
axes, which are each adjusted at an angle relative to the
longitudinal axis of the bar-shaped or tubular workpiece to be
processed. The workpiece extends coaxially with the central
axis of the roller head through central openings of the
bearing discs and is non-rotationally clamped on its two ends.
The profiles of the successive shaping roller assemblies
differ slightly, thus accounting for the fact that the shaping
rollers come into engagement with the workpiece one after the
CA 02772658 2012-02-29
3
other. The mounting of the shaping rollers is realized by axle
pins whose ends are fixedly disposed in the bearing discs. The
shaping roller is supported on the axle pin by a central
radial bearing and by axial bearings, via interposed spacer
rings. The spacer rings provided on both sides have different
axial dimensions so as to enable a change in the position of
the shaping roller on the axle pin at an unchanged axial
locating distance, merely by exchanging the entry-side and
exit-side spacer rings such that, at a unilaterally occurring
wear of the axle pin, the worn portion will come into a less
highly stressed zone so as to provide an improved material
exploitation of the axle pin.
In order to ensure, in those known roller heads, that at every
shaping roller assembly a shaping engagement with the
workpiece is provided such that the shaping rollers will come
into engagement one after the other, viewed in the direction
of revolution of the roller head, different shaping rollers
that meet this criterion are used. These shaping rollers are,
however, prone to considerable wear such that the operators of
those devices have to keep on standby adequate numbers of
different shaping rollers. The required stock of shaping
rollers will thus increase as a function of the number of
shaping rollers per shaping roller assembly and of the number
of shaping roller assemblies per such device.
The invention aims to configure a device of the initially
defined kind by simple means with a view to providing a more
efficient operation of the same, on the one hand, and making
the device adaptable to the most different workpiece wall
thicknesses and diameters as well as threads and surface
profiles to be formed, on the other hand.
CA 02772658 2012-02-29
4
To solve these objects, a device according to the invention is
essentially characterized in that at least two axially
successive shaping roller arrangements are provided in the
passing direction of the workpiece, that at least the shaping
rollers of a shaping roller arrangement are the same as one
another, and that the axial position of each shaping roller
within an axial installation dimension is different in order
to provide shaping engagements with the workpiece that are
successive in the direction of the revolution around the
workpiece, and that at least three shaping rollers are
arranged in each shaping roller arrangement. In that at least
two axially successive shaping roller arrangements are
provided, it has, on the one hand, become possible to process
workpieces having different workpiece diameters and/or
different wall thicknesses, for instance by providing a wall
thickness and/or diameter reduction by means of the first set
of shaping rollers and by forming a thread-like outer profile
by means of the second set of shaping rollers. In that, in
order to provide shaping engagements with the workpiece
successively in the direction of the revolution around the
workpiece, the axial position of each shaping roller within an
axial installation dimension is, moreover, differently
conceived as opposed to the known prior art, successive
shaping engagements of shaping rollers that are consecutively
arranged in the direction of revolution can be provided by
varying the axial position of the shaping profile. This also
means that for the operation of the shaping roller arrangement
a single shaping profile that can be fixed in different axial
positions will do, which results in a considerable reduction
of different shaping profiles and shaping rollers provided
therewith.
CA 02772658 2012-02-29
According to a preferred further development of the invention,
the device is characterized in that the shaping roller
arrangement is comprised of a roller head that is rotationally
drivable about its central axis, which extends coaxially with
the workpiece during processing, and in which the shaping
rollers are freely rotatably mounted on axle pins. In that the
individual shaping rollers are mounted to be freely rotatable
about their respective axes, with the roller head being
rotationally drivable about its axis as a structural unit, it
has become possible to better control the formation of, and
hence more precisely configure, the thread-like outer profile
while, at the same time, increasing the processing speed.
Alternatively, it is also possible, as in correspondence with
a further development of the invention, that in the context of
a shaping roller arrangement also each shaping roller is
directly drivable about its axis, or the shaping rollers of
the shaping roller arrangement are rotationally drivably
mounted.
In that, as in correspondence with a preferred further
development of the invention, the axes of the shaping rollers
are adjusted at a respective angle relative to a longitudinal
axis of the workpiece, or the central axis of the shaping
roller arrangement, it will, on the one hand, be possible to
arbitrarily define the advance of the workpiece through the
device and, on the other hand, in connection with e.g. a
pitchless, groove-like shaping profile, the pitch measure of
the thread-like formation to be introduced into the outer side
of the workpiece will result from said angle. Similarly, the
extent of the material taper or calibration of the introduced
workpiece will be derived if, for instance, a plain shaping
roller is applied. Such a configuration in a preferred manner
CA 02772658 2012-02-29
6
enables tubes or pipes and rods with different diameters to be
profiled, tapered and/or calibrated on one and the same
device. A further improvement or precision enhancement will be
achieved according to a preferred further development of the
invention in that the adjustment angle is adjustable as a
function of the dimensions of the workpiece and/or the
material of the workpiece.
According to a preferred further development of the invention,
the device, as a constructive concretization of the axial
adjustability of a shaping profile of a shaping roller, is
characterized in that the axle pins of the shaping rollers are
non-rotationally fixed about their respective axes in the
roller head. To this end, at least one adjusting disc is each
located on either side of the shaping profile, whose two axial
lengths together with the length of the shaping profile
complete one another to said installation dimension. The two
adjusting discs will thus generally have different axial
dimensions as a function of the axial position of the shaping
profile to be adjusted. This means that, as opposed to the
initially mentioned prior art, only adjusting discs having
different dimensions will have to be kept on standby besides
one or a few standard shape(s) of a shaping profile in order
to exchange worn parts if need be.
According to a further preferred structural configuration of a
shaping roller and, in particular, its mounting within the
roller head, the invention is characterized in that a fixed
installation dimension of the shaping rollers is ensured by
adjusting discs provided on both sides of a shaping profile of
the shaping roller. In this case, the axle pin carrying the
shaping roller is non-rotationally received in the roller
head, wherein, in order to provide reference or abutment
CA 02772658 2012-02-29
7
surfaces documenting said installation dimension, structural
elements are used, which are present anyway, for instance
structural elements that serve to fix the axle pins within the
roller head, wherein the shaping profile of each shaping
roller is preferably mounted radially on the axle pin in a
central region, and axially on the two end-side end regions.
According to another preferred further development of the
invention, the device is configured such that said
installation dimension is provided by the axial distance of
the reference surfaces of structural elements used to fix the
axle pins in the roller head, and that an axial support of the
shaping profile on said structural elements is provided via
the adjusting disc. In that all of the functional elements
intended to mount the shaping profile are included in the
structure of the latter, it is possible to provide
reproducible conditions such that the mutually opposite end
faces of the shaping profile will always be usable as abutment
surfaces for the adjusting discs, thus clearly reducing the
wear of the device while, at the same time, increasing the
processing precision.
In that, as in correspondence with a preferred further
development of the device according to the invention, at least
three shaping roller arrangements are provided in axial
succession in the passing direction of a workpiece, it has
become feasible to apply the whole shaping work stepwisely. In
accordance with the invention it is possible, with the shaping
operation progressing in the passing direction of the
workpiece, that either the radial dimensions of the shaping
rollers inserted in the shaping roller arrangements, yet not
their profile shapes differ from one another, or that both the
radial dimensions of the shaping rollers inserted in the
CA 02772658 2012-02-29
8
shaping roller arrangements and their surfaces or surface
structures differ from one another.
According to a preferred further development of the invention,
the device is substantially configured such that at least
three shaping rollers are arranged in each shaping roller
arrangement, and that the shaping rollers of a shaping roller
arrangement are arranged to be offset relative to those of the
adjacent shaping roller arrangement in the radial direction by
a full circle divider corresponding to the number of shaping
rollers. In that at least three shaping rollers are disposed
in each shaping roller arrangement, a rapid and exact surface
treatment or shaping treatment of the workpiece to be
processed will be feasible, and in that, furthermore, the
shaping rollers of mutually adjacent shaping roller
arrangements are arranged to be offset by a full circle
divider corresponding to the number of shaping rollers,
particularly uniform processing of the surface of the
workpiece to be processed will be feasible, whereby, due to
the permanent engagement of the shaping rollers with the
workpiece to be processed, also surface and/or structural
changes of the workpiece to be processed will be additionally
achieved by a heat treatment.
In that, as in correspondence with a preferred further
development of the invention, the device is configured such
that the shaping rollers of a shaping roller arrangement
relative to those of the adjacent shaping roller arrangements
comprise shaping profiles having mutually different profiles,
it is feasible by one and the same arrangement to, for
instance, coarsely process a workpiece to be processed in a
first step and finely process, or finish, the same in a second
CA 02772658 2012-02-29
9
step. Such a device is, of course, arbitrarily expandable such
that even a plurality of processing steps can be performed.
In a further preferred modification of the invention, the
device is configured in a manner that the shaping rollers of a
shaping roller arrangement relative to those of the adjacent
shaping roller arrangement have mutually different diameters.
By such a device it is, for instance, possible for a workpiece
to be processed to reduce the wall thickness or the diameter
of the workpiece in a first step, to coarsely apply a thread-
like profile in a second step, and to finish the latter in a
third step. By such a device it is, for instance, also
possible to merely calibrate the workpiece to be processed in
a first step, to form a thread pre-profile in a second step,
and to correctly form or post-process said thread in a third
step.
Such a configuration, in particular, enables an increase in
the throughput and renders feasible the adaptability of one
and the same device to different workpiece cross-sections or
diameters without having to keep on stock a multitude of
different shaping rollers.
In that, as in correspondence with a further development of
the invention, the device is configured such that an intake
region into the shaping roller arrangement for the workpiece
is designed as an adjustable cone, one and the same roller
head can be used for different material cross-sections, and
such a configuration will, furthermore, ensure a rapid and
reliable introduction of the workpiece into the shaping roller
arrangement while simultaneously processing the end region of
the workpiece, e.g. by reducing its diameter or wall
thickness.
CA 02772658 2012-02-29
In that, as in correspondence with a further preferred
configuration of the present configuration of the invention,
the device is configured such that the shaping rollers of each
shaping roller arrangement can be arranged on arbitrarily
selectable and mutually different pitch circles, it is
possible to further reduce the number of shaping rollers to be
kept on stock, since partially worn shaping rollers can, for
instance, be disposed on a smaller pitch circle and
subsequently further used until they are ultimately worn.
The present invention aims, moreover, to a method for non-
cuttingly shaping elongate workpieces using a device of the
present invention, by which method surface refining of the
workpiece to be processed will be additionally achieved while
forming a thread-like outer profile.
For solving this object the inventive process is characterized
in that at least two shaping roller arrangements in axial
succession are brought into engagement with the workpiece in
the passing direction of the workpiece and that, in order to
provide successive shaping engagements with the workpiece in
the direction of the revolution around the workpiece, the
axial position of each shaping rollers is differently adapted
within an axial installation dimension. In that, in the
passing direction of the workpiece, at least two successive
shaping roller arrangements are brought into engagement with
the workpiece, it is feasible during processing of the
workpiece to achieve a considerable temperature development,
in particular in the successive shaping engagements with the
workpiece, such that simultaneously with the surface
processing or change in the diameter or change in the wall
thickness of the workpiece hot-forming of the worked end
CA 02772658 2012-02-29
11
region of the elongate workpiece to be processed is achieved,
which causes the end region in relation to the remaining
elongate workpiece to be subjected to a hardening treatment by
a structural change of the material, thus increasing the
service lives of the devices produced by the method according
to the invention. With such a method control, workpieces
having smaller wall thickness will, moreover, do such that the
required amount of raw material can also be reduced.
In that, as in correspondence with a further development of
the method according to the invention, the latter is conducted
in a manner that the shaping roller arrangement is driven to a
rotational movement by a roller head rotating about its
central axis, which extends coaxially with the workpiece
during processing, wherein the shaping rollers are freely
rotationally mounted on axle pins in the shaping roller
arrangement, the wear of the shaping rollers in the shaping
roller arrangement will be minimized so as to clearly reduce
the stock inventory of shaping rollers, on the one hand, and
readily and reliably enable the quick adaptability of the
method to different materials, material conditions and
processing times, on the other hand.
In that, in said method according to the invention, it is
proceeded in a manner that the shaping rollers of a shaping
roller arrangement comprise shaping profiles having different
profilings relative to those of the adjacent shaping roller
arrangement, or that the shaping rollers of a shaping roller
arrangement comprise shaping rollers having different
diameters relative to those of the adjacent shaping roller
arrangement, it is feasible to use the method according to the
invention for calibrating a workpiece or processing workpieces
having different diameters or different wall thicknesses,
CA 02772658 2012-02-29
12
without the shaping rollers being exchanged or excessively
stressed and prematurely worn. At the same time, such a method
enables a structural change of the material structure in the
worked end region of the workpiece so as to further increase
the service lives of the processed workpieces.
In the following, the invention will be explained in more
detail by way of exemplary embodiments illustrated in the
drawing. Therein:
Fig. 1 is a side view of a roller head according to the
invention;
Fig. 2 is a view of a shaping roller as part of the roller
head according to Fig. 1 in an enlarged partial illustration;
Fig. 3 is an explosive view of a single shaping roller of the
roller head according to Fig. 1;
Fig. 4 is a side view of a roller head according to the
invention with two shaping rollers;
Fig. 5 is a top view on the end face of the roller head
according to Fig. 4; and
Fig. 6 is a side view of a modified embodiment of a roller
head according to the invention, in which three shaping
rollers are provided.
In Fig. 1, four identical, circular bearing discs extending in
parallel and coaxially with one another are denoted by 1, 2,
3, 4, said bearing discs being held in their shown mounting
positions at mutually uniform distances by the aid of spacers
5. The spacers 5 are uniformly distributed about the
peripheries of the bearing discs 5 and can be screwed with the
same.
CA 02772658 2012-02-29
13
The thus designed roller head 6 is intended to be mounted in a
machine frame, which is not illustrated in the drawing, and
rotationally drivable in the same about its axis 7.
All of the bearing discs 1 to 4 are provided in a central
region with registering, circular recesses extending coaxially
with the axis 7, through which the elongate rod-shaped or
tubular workpiece to be processed in its peripheral region for
the purpose of producing a thread-like formation, which is not
illustrated in the drawing, extends during the operational use
of the roller head 6. The workpiece, which is held coaxially
with the axis 7, in a manner known per se is non-rotational
about is axis while being processed by the aid of the roller
head 6, yet is mounted to be movable in the direction of its
axis, for instance by the aid of a hydraulic carriage.
The illustrated roller head 6 is characterized by three
shaping roller arrangements or assemblies 9, 10, 11, which are
successively arranged in the passing direction 6 of the
workpiece and each comprise three shaping rollers 12, 13, 14
that are disposed in a uniformly distributed manner in the
peripheral direction and of which only one is shown in Fig. 1
for the sake of drawing simplicity.
The shaping rollers 12, 13, 14, i.e. their annular-cylindrical
shaping profiles 12", 13", 14", are mounted to be freely
rotatable about their respective axes 12', 13', 14', which
axes are adjusted at a respective angle relative to the axis 7
of the roller head 6. This angular adjustment in connection
with the rotational movement of the roller head 6 and the non-
rotational, yet axially displaceable reception of the
workpiece provides the pitch measure of the thread-like
CA 02772658 2012-02-29
14
formation and the axial advance acting on the same during
operation.
The shaping rollers 12, 13, 14 of each shaping roller assembly
9, 10, 11 differ in terms of their positioning on the
respective axle, said positioning being adapted as a function
of the direction of revolution of the roller head 6 to the
effect that the peripherally successive shaping rollers 12,
13, 14 of a shaping roller assembly 9, 10, 11 will enter into
engagement with the workpiece one after the other.
The shaping rollers 12, 13, 14 of the successive shaping
roller assemblies 9, 10, 11 differ in terms of their radial
dimensions to the effect that these will increase as a
function of the shaping progressing in the passing direction
8.
Fig. 1 only exemplarily depicts three shaping roller
assemblies. In practice, a roller head can also be comprised
of two or more than three shaping roller assemblies succeeding
one another in a passing direction.
To elucidate the mounting of the individual shaping rollers of
a shaping roller assembly, it is in the following additionally
referred to Figs. 2 and 3, in which identical functional
elements are equally referenced.
Figs. 2 and 3 illustrate the shaping profile 12" of the
shaping roller 12 as an annular-cylindrical base body
externally comprising a profile in the form of an array of
pitchless rings, which is provided with identically
dimensioned turned grooves 15 on both of its end sides. This
annular profile is intended for the production of an at least
CA 02772658 2012-02-29
approximated round thread on the workpiece and should only be
regarded as an example. Other thread-like formations can be
similarly produced by an appropriate shaping roller profile.
By 16, a radial bearing, e.g. a cylindrical roller bearing, or
a system of locating pins is denoted, via which the shaping
profile 12" is radially supported on an axle pin 17.
By 18, spacer discs are denoted, via which the shaping profile
12" is supported on both sides on an axial bearing 19, one
spacer disc 18 and one axial bearing 19 each filling a turned
groove in an axially flush manner.
By 20, 21, sleeves are denoted, which are intended to be non-
rotationally inserted into bores 22, 23 of two axially
opposite bearing discs 1, 2, said bores extending in the
direction of the axis 12' of the shaping roller 12 in its
installed state. The identically dimensioned end portions 24,
of the axle pins 17 can be inserted and non-rotationally
fixed in said sleeves 20, 21. This rotationally fast fixation
can, for instance, be positively realized by groove-and-tongue
engagements.
By 26, 27, two adjusting discs are finally denoted, via which
the two axial bearings 19 are axially supported on the facing
end faces of the sleeves 20 and 21, respectively. The axial
installation dimension 28 between the mutually facing end
sides of the sleeves 20, 21 is identical for all three
installation positions of the shaping roller assembly 9. It is
preferably also identical for all installation positions of
the roller head 6.
CA 02772658 2012-02-29
16
In accordance with the invention, the adjusting discs 26, 27
on both sides of a shaping roller 12 are selected with the
proviso that, while maintaining the installation dimension 28,
the axial positions of the shaping profiles 12", 13", 14" of
the shaping rollers 12, 13, 14 of the shaping roller assembly
9, 10, 11, respectively, on the respective axle pins 17 are
differently conceived with a view to bringing the shaping
profiles 12", 13", 14", which are successively arranged in the
direction of revolution of the roller head 6 within a shaping
roller assembly 9, 10, 11, one after the other into engagement
with the workpiece during a processing operation. This will
only require appropriate pairs or combinations of adjusting
discs 26, 27 to be available on standby, which, in combination
with the axial dimensions of the shaping rollers, are suitable
for constituting the installation dimension 28.
Identical shaping rollers can thus be used for any
installation position of at least one shaping roller assembly
9 irrespectively of their concrete installation position.
In the illustration according to Fig. 4, in which the
reference numerals of the preceding Figures have been
retained, three bearing discs 1, 2 and 3 are shown, which are
connected to one another, and held at equal distances, by
spacers 5. In a thus designed roller head 6, a workpiece to be
processed will be supplied along the axis 7, and the shaping
rollers 11 disposed in the shaping roller assembly 9, of which
three are provided in Fig. 4 and which have shaping profiles
12' formed on their surfaces, will be brought into engagement
with said workpiece supplied along the axis 7. They will
perform a first, coarse profiling step or first coarse step
for forming a thread-like surface. As the workpiece is moved
on in the direction of the axis 7, the pre-processed workpiece
CA 02772658 2012-02-29
17
will reach the second roller assembly 10, in which final
processing or post-processing of the thread-like surface
profile of the workpiece will be carried out.
Such an arrangement, in particular with the shaping rollers 12
mounted in the manner described in the preceding Figures, not
only allows for the non-cutting shaping of a workpiece and, in
particular, the application of a thread-like structure, but at
the same time enables the processed end region of the
workpiece to be subjected to heat-refining due to the high
temperature forming during the processing procedure, so that a
workpiece that is subjected to such a processing operation is
simultaneously refined in its end region, thus having a higher
lifetime or service life than conventional workpieces.
It goes without saying that the profiles of the rollers 11 may
be configured identically with, or differently from, one
another in the individual shaping roller assemblies 9, 10,
whereby the stock of shaping rollers can be kept extremely
low, in particular, due to the fact that with a slightly worn
surface contour of one of the shaping rollers 12, the latter
can be immediately installed and used in a device comprising a
smaller pitch circle.
It is possible to use both shaping rollers 12 with accordingly
coarse or fine profiles and shaping rollers having smooth
surfaces, by which, for instance, a change in the diameter, a
reduction of the wall thickness, or the like, of a workpiece
to be processed can be achieved prior to applying a thread.
Fig. 5 depicts the device of Fig. 4, viewed in the direction
of the axis 7, the respective axial bearings 19 of the shaping
rollers 12 in this Figure being denoted by A, B and C. The
CA 02772658 2012-02-29
18
bearings for the spacers 5 are also schematically indicated.
At the same time, it is apparent from Fig. 5 that the shaping
rollers 12 of the first shaping roller assembly 9 are arranged
to be offset relative to those of the second shaping roller
assembly 10 by a full circle divider corresponding to the
number of shaping rollers 12, so that, in particular, uniform
and quick processing as well as an accelerated throughput of
the workpiece to be processed through the roller head 6 will
be enabled.
The illustration according to Fig. 6 substantially corresponds
to that of Fig. 4 such that it is referred to Fig. 4
concerning the description of the first two shaping roller
assemblies 9, 10 of this Figure.
The shaping roller assembly 11 in this case is configured such
that instead of the individual shaping rollers 12 only their
axle pins 17 are illustrated, so that the device according to
Fig. 6 can be adapted for use in a third processing step for
elongate workpieces to be non-cuttingly processed, for
instance by providing further shaping rollers 12 on the axle
pins 17 of the shaping rollers assembly 11.
In addition, a drive 29 for the roller head 6 is schematically
indicated in Fig. 6.
There is no need to point out that the device according to the
present invention can be expanded in any manner whatsoever,
and that also more than three shaping roller assemblies can be
provided as a function of the processing steps to be
performed.
CA 02772658 2012-02-29
19
In case of wear, the shaping profiles of a shaping roller
assembly, based on the absolute dimensions, can be exchanged
with those of a shaping roller assembly arranged upstream in
the passing direction in order to achieve an improved material
exploitation. In this case, the simple axial adjustability of
the shaping profile on the respectively supporting axle pin is
beneficial.
