Roller assembly for expanding the width of a web

A widening device for increasing the width of a moving web of material comprises a rotatable profiled roller, the outer surface of which defines a plurality of radial projections and recesses distributed along the length of the roller and first and second co-operating rollers rotatable at the same speed as the profiled roller. The first and second co-operating rollers define projections and recesses complementary to those of profiled roller and define first and second treatment nips which serve to increase the width of a web of material passed therethrough. The projections on the co-operating roller defining the second treatment nip extend more deeply into the recesses of the profiled roller than do the projections on the co-operating roller which defines the first treatment nip so that the web of material is stretched gradually over two stages with the stretching effect being uniform across the entire width of the web.

THE PRESENT INVENTION relates to a widening device and more particularly a 
widening device for increasing the width of a moving web of material. 
DE-PS 30 067 discloses a widening or width-extending device in which a 
textile web of material is unwound from a roll, conveyed through the nip 
between co-operating profiled rollers, and rewound. A width-stretching 
device can be disposed in front of and behind the nip. The co-operating 
rollers have their periphery formed with a helical relief extending from 
the centre of the rollers outwards to both sides and with a constant 
pitch, but opposite on either side of the centre. This relief meshes with 
a corresponding relief on the co-operating roller, so that the peaks of 
the relief on one roller engage in the troughs between the peaks of the 
relief on the other roller. The two rollers can be adjusted relative to 
one another in a controlled manner. 
For the purposes of the following description, the term "width-extending or 
extension" means transverse stretching, i.e. a change in the dimensions of 
the web of material in the width direction, and is associated with 
considerable stretching forces exerted across the material. In contrast 
the term "width stretching" is used to describe the operation where a web 
which is not completely flat is simply spread out and flattened, when only 
relatively small forces are exerted across the web. 
The "width-extending" effect, in the present sense, of the known device is 
based on the fact that the web, which would normally be flat when running 
through the nip, is pressed by the peaks on one roller into the troughs 
the peaks on the other roller. In the process it is held by friction 
against neighbouring peaks, so that penetration is opposed by a force 
which results in stretching. The web extends in a zigzag in the nip, and 
where there is no substantial change in the position of the edges, the 
result is, of course, a greater extension of the web in the width 
direction, i.e. the web is transversely stretched. The amount of 
transverse stretching depends on the extent to which the helical reliefs 
on the two co-operating rollers engage in one another. If the engagement 
is deep, the web may quite possibly be torn into longitudinal strips. 
The aim of the known device is to equalise the locally attainable width 
extension across the web. Another width-extending device is a tentering 
frame having tenterhooks which engage the edges of the web and pull them 
apart. This however results in an approximately hyperbolic variation in 
stretch across the width. The stretching at the edge is greatest and there 
the weft density of the finished product is considerably smaller. These 
differences in stretching also show up when the web has been treated, e.g. 
in the colour shade. 
In the case of the width-extending device of DE-PS 30 067, stretching 
occurs at a number of places uniformly distributed across the web between 
each pair of peaks, which are separated by about 1 to 2 cm. The forces are 
applied, not at widely distant places but in the immediate neighbourhood 
of each place under consideration. The conditions are the same at all 
places, at least within the width of the web. The resulting stretching is 
correspondingly constant. The places where force is applied are much less 
stressed than in the tentering frame, because instead of forces being 
applied at two locations, (at the edge of the web), it is applied at about 
a hundred positions following one another in line along the 
width-extending nip. 
DE-PS 30 067 dates from the year 1884. In the meantime the effect 
attainable by the device has been given new importance by the 
"micro-elongation" (abbreviation ML) process (see Textilbetrieb 95 (1977), 
pages 58 to 60). The aim is to increase the width of the product without 
reducing the length, or to retain a given width in order to counteract 
shrinkage during the various textile wet-treatment processes. The 
intention is to increase the area of the high-finished final product by a 
small percentage. The ML process is performed on a device substantially 
similar to that in DE-PS 30 067. 
In spite of the worthy object of increasing the useful area of the product 
by a small percentage, thus justifying considerable investment, the ML 
process has not been successful in practice. The reason is that although 
the product can be uniformly stretched in the desired manner inside the 
width of the web, the effect is not maintained at the edge, because when 
the web is subjected to tensile stresses the edge is pulled into the 
width-extending nip from the side, because the tensile stresses at the 
edge cannot be counteracted by any opposing forces. The stretch obtainable 
by the known device is therefore in the form of a curve symmetrical 
towards the middle and falling at the edges. This non-uniform stretching 
has such an effect on the result of treatment that the product cannot 
satisfy stringent requirements. 
Attempts have been made to hold the material particularly firmly at the 
edge, by inserting elastic rings into the troughs in the relief on one 
roller, so as to abut the peaks on the relief in the other roller forming 
the nip. In this manner the material is firmly clamped at the edge and 
cannot slide inwards. This remedy, however, is suitable only for one width 
of web, and considerable work is involved in attaching and adjusting the 
elastic rings. 
DE-AS 26 13 822 discloses another width-extending device in which a smooth 
cylindrical pressure roller presses externally on the peaks of the relief 
on a roller over which the web runs, in the part of the roller covered by 
the web, and clamps the web between it and the peaks at a number of 
positions across the web, and also at the edge. The peaks have the same 
radial height, measured from the roller axis. This results in a number of 
securing or retaining points across the width of the web, and at these 
points the web cannot be displaced in the width direction. These securing 
or retaining points are disposed very near the width-extending nip. 
Accordingly when the web runs into the nip, its edge can only follow the 
transverse tensile forces resulting from engagement of the relief to a 
very limited extent, and is prevented from sliding into the nip from the 
sides. In this manner the stretch resulting from "engagement" of the 
reliefs on the co-operating rollers is equalized across the width and, 
more particularly, is also maintained at the edge. Accordingly, the 
pressure roller, having the same length as the co-operating relief 
rollers, enables the co-operating relief rollers to produce useful 
"micro-elongation" in the transverse direction of the web. This effect can 
be achieved with various widths of processed webs, without the need for 
any adjustment. 
Now that the uniformity of stretching has been substantially increased by 
the pressure roller as per DE-AS 26 13 822, the remaining problem is that 
if the required stretching is performed in a single step, the web material 
will be considerably stressed, possibly up to the limit of its tensile 
strength. 
The aim of the invention is to provide an improved width-extending device 
which addresses this problem so that the effect on the web is gentler. 
SUMMARY OF THE INVENTION 
There is provided a device for increasing the width of a moving web of 
material, the device comprising a rotatable profiled roller, the outer 
surface of which defines a primary plurality of radial projections and 
recesses distributed along the length of the roller. First and second 
co-operating rollers are provided rotatable at the same speed as the 
profiled roller, defining first and second treatment nips with the 
profiled roller. The nips serve to increase the width of a web of material 
passed therethrough. The surface of each co-operating roller defines first 
and second projections and recesses complimentary to the projections and 
recesses of the profiled roller such that the projections on each of the 
co-operating rollers extend into the recesses of the profiled roller 
without contact. The projections on the second co-operating roller extend 
more deeply into the recesses of the profiled roller than the projections 
on the first co-operating roller. The device is constructed so that, in 
use, a web of material, the width of which is to be increased, is passed 
through the first treatment nip defined between the first co-operating 
roller and the profiled roller and then passes around part of the profiled 
roller before passing through the second treatment nip defined between the 
second co-operating roller and the profiled roller. 
In an arrangement of this kind, two width-extending nips are present and 
the desired total stretching can be brought about, without considerable 
additional complication, in two stages. Between the stages web can 
mechanically "recover", particularly if the web runs through a liquid bath 
between stretching operations. 
Preferably the device incorporates a pressure element which engages firmly 
against a web of material passing through the first and second treatment 
nips at a position relatively close to the nips, the pressure element 
being movable with the moving web of material and having a pressure 
surface which forces the web of material against the co-operating rollers. 
Preferably a single pressure element engages the web of material at two 
positions, first as it passes around the first co-operating roller and 
second as it passes around the second co-operating roller. 
The invention provides uniform stretching across the web without stressing 
the web unduly. It has been found that the invention can improve the 
penetration of liquid or gaseous substances into the material and into the 
fibres and filaments, and the stretching can be effective before, during 
or after the substances are supplied. 
The pressure element may have an unbroken or smooth pressure surface. This 
embodiment is the easiest to manufacture and produces uniform pressure if 
the raised portions of the reliefs on the co-operating rollers lie in a 
cylindrical surface. 
Alternatively the pressure element may have a perforated pressure surface. 
During stretching, a treatment medium can be supplied or discharged 
through the perforations. 
A pressure element performing this function substantially without friction 
can have various geometrical shapes. 
In one preferred embodiment the pressure element is a pressure roller 
extending over the length of the co-operating rollers. This roller 
produces a linear or very narrow pressure zone extending along the 
pressure roller. 
Preferably the pressure roller has a flexible coating with a hardness of 50 
to 70 Shore D. This provides uniform pressure and retention of the web. 
The pressure roller will usually be a naturally rigid cylindrical roller of 
conventional kind. This implies, however, that the raised portions of the 
relief on the co-operating roller lie in a cylindrical surface, though 
this is not always so. The pressure roller may therefore be divided into 
longitudinal portions, with the axes of the longitudinal portions being 
movable at an angle with respect to one another. Thus the pressure roller 
may be a width-extending roller. 
In an alternative embodiment, the pressure element is an endless rotating 
belt approximately equal in width to the length of the co-operating 
rollers, the belt engaging the outer surface of the co-operating rollers. 
The belt provides a pressure region over a larger peripheral angle, as 
compared with a pressure roller. 
The belt, besides increasing the pressure area and thus more efficiently 
securing the web in the transverse direction, has further advantages in 
that the web is supported without a break in the pressure region. This may 
be an advantage in certain forms of treatment with a liquid medium during 
width extension. It is not necessary, however, for the belt to have an 
unbroken surface; it can be perforated or have a surface relief like the 
pressure roller. 
In one arrangement, the radial projections and recesses defined by the 
outer surfaces of the profiled roller and the co-operating rollers form a 
relief and comprise continuous ribs extending around the periphery of the 
rollers. 
While the width-extending device can have ribs extending in planes at right 
angles to the axis, in practice there is a risk of longitudinal markings 
on the web. Preferably therefore the relief is a helix, which can be 
continuous without any transverse transport effect and without marking. 
Alternatively the helical relief can be as per DE-PS 30 067, in which the 
turns of the helix have an opposite but equal pitch from the centre 
outwards. 
In a different arrangement, the radial projections and recesses defined by 
the outer surfaces of the profiled roller and the co-operating rollers 
form a relief and comprise individual raised portions uniformly 
distributed over the roller surface, the raised portions being spaced from 
one another in the longitudinal and peripheral directions. 
The individual raised portions may take the form of knobs or diamond-shaped 
lands. 
The only general limitation to the shape of the relief is that it must be 
able to extend the width and ensure mutual engagement during rotation 
without touching of flanks. 
Preferably the radial projections defined by the outer surface of each 
roller have peaks which are spaced apart in the longitudinal direction of 
the roller by a distance of between 5 and 30 mm. 
Conveniently, the radial projections define peaks and the radial recesses 
define troughs, the peaks and troughs each lying on an imaginary 
cylindrical surface and the radial distance between the cylindrical 
surfaces is between 5 and 20 mm. 
These dimensions relate to the conventional dimensions of woven textile 
webs, which are up to 2 m wide. 
Advantageously the peaks of the raised portions are rounded, to prevent 
excessive friction or even cutting stresses on the web at the edges of the 
raised portions over which the web is drawn under tension between the 
raised portions. 
Various textile webs offer differing resistance to treatment in the 
width-extending nip. In spite of the already-achieved equalization of 
local stretching across the web by the pressure element, some webs exert 
such strong forces counteracting effective stretching that there is always 
an appreciable decrease in stretch towards the end. 
The depth of penetration of the projections on the co-operating rollers in 
the recesses of the profiled roller may decrease towards the ends of the 
rollers. This feature may be of interest even where there is no pressure 
roller or belt, and has the effect, that at the sides the engagement is 
less deep and the transverse stretching of the web is correspondingly 
less. Then the otherwise hyperbolic variation is counteracted. The amount 
of decrease in the peak height and the distribution of the increase across 
the web will be determined in individual cases in accordance with the 
properties of the materials being processed. If a pressure roller is 
present and if the outer periphery of the profiled roller is not 
cylindrical, the pressure roller must adapt to the shape of the profiled 
roller. 
Thus, the peaks of the projections on the roller surfaces may lie on a 
surface of rotation which is symmetrical about a central plane extending 
at right angles to the longitudinal axis of the roller, with the radius of 
the surface of rotation increasing in a direction from the ends of the 
roller towards the central plane of the roller. 
A device for supplying a liquid treatment medium to the web may be provided 
near one of the treatment nips. 
Preferably the device supplies the liquid treatment medium to the web 
before it enters the nip. The treatment medium can advantageously 
influence the stretching process. The medium may be water or an alkaline 
liquid supplied in a quantity of 50 to 300% of the dry weight of material 
at temperatures of 15.degree. C. to 100.degree. C., preferably about 
80.degree. C. 
A device for sucking a liquid treatment medium through the web may be 
provided near one of the treatment nips. The suction device is used for 
distributing a sprayed or otherwide applied treatment medium through the 
thickness of the web. 
Preferably at least one of the rollers forming the first treatment nip is 
perforated and the interior of the roller is connected to a device for 
blowing a liquid treatment medium out or sucking it in. 
Most preferably, one of the rollers forming the first treatment nip is 
connected to a device for blowing out a liquid treatment medium towards 
the nip, and the other roller is connected to a device for sucking in a 
liquid treatment medium from the nip. This results in an intense flow 
through the web at the moment when it is transversely stretched. 
Conveniently a web of material passing through the device extends around 
the outer surface of the profiled roller by an angle .alpha., and around 
the outer surfaces of the first and second co-operating rollers by angles 
.beta. and .gamma. respectively, the angle .alpha. being equal to the sum 
of the angles .beta. and .gamma.. This avoids warping of the web where the 
profiled and co-operating rollers have a surface relief defined by helical 
ribs. 
Advantageously, at least the profiled roller dips at least partly into a 
treatment liquid. In this way, width extension of the web is combined with 
treatment of the web with a liquid. 
Since the profiled roller is dipped into the treatment liquid the part of 
the web of material which is passed around the profiled roller is further 
impregnated with the treatment liquid during or after passing through the 
treatment nip. This assists in the treatment of the web with the liquid or 
in the recovery of the web material between successive stretching 
operations. 
Preferably the rollers are adjustable to provide a predetermined depth of 
penetration of the radial projections on one roller into the radial 
recesses of another roller with which a nip is defined. 
The simplest arrangement is to continuously adjust the rollers to provide 
the desired depth of engagement and this may, for example, be effected by 
means of spindle drives engaging the ends of the rollers. A user who is 
very familiar with the characteristics of the articles which are to be 
treated can adopt this procedure if he knows the maximum weft thread 
stress which the material can withstand. It is then possible to set a 
working condition at which the stress is, of course, at a safe level below 
the level at which damage would occur. 
Alternatively the rollers may be adjustable to provide a predetermined 
force urging the rollers defining a nip towards each other. This is a 
better way of adapting the working conditions to the properties of the 
material and also gives greater protection against tearing of the web. 
In this case it is the web itself which will determine the depth of 
penetration of the relief in the nip and will also determine the 
adjustment of the stretching which is achieved. Instead of the 
predetermined force being set and adjusted externally or manually, for 
example on the basis of values derived from experience, a computer can be 
provided to analyze the variation in the force of extension when the force 
is increased on a given material. If the material begins to tear, i.e. if 
the increase in force is no longer proportional to stretching within the 
elastic region, a limiting value will have been reached and the computer 
will provide a command to a regulator for the force not to exceed a 
predetermined limit which is of course less than the maximum tolerable 
value by an appropriate safety margin. In this way stretching of the web 
can be adjusted completely automatically in a precise manner without the 
risk of damaging the properties of the individual product being treated. 
In order to provide automatic operation it is desirable for the device to 
be associated with a batch identification device which responds to 
markings on the web and which is used to control the adjustment of the 
rollers. The batch-identification device may respond to markings at the 
beginning and the end of a portion of web, for example, the front or the 
rear of a batch. The device will be used automatically to adjust the nip 
as necessary, e.g. to initiate `infeed` or rapid ventilation. 
The increase in area of the web of material as a result of the 
width-extension is of importance and it is therefore convenient that the 
device is associated with a device for measuring the moving web, the 
measuring device being connected to a device for controlling the rollers. 
Preferably the device is disposed in front of a width-stretching device. 
After leaving the second treatment or width-extending nip, the web has a 
corrugated form with peaks and troughs in the longitudinal direction and 
passing the web through the width-stretching device prevents the web from 
creasing which could otherwise cause difficulties during subsequent 
treatment when the web runs in a continuous plant. The width-stretching 
device transversely spreads and flattens the web. 
The device of this invention may be used at various locations in a 
continuous treatment plant. 
Thus the device may be disposed in front of a mangle or may be disposed in 
front of a steam box, outside the casing thereof or may be disposed in 
front of the actual recovery section in a steam box.

DETAILED DESCRIPTION 
FIG. 1 shows the basic features of a width extending device 100 which 
comprises a profiled roller 1 and two co-operating rollers 2, 3. The 
co-operating rollers extend parallel to each other and to the profiled 
roller 1 and are located at the same height slightly above the level of 
the profiled roller 1 and on either side thereof. Thus, the co-operating 
rollers 2, 3 may be considered to be located adjacent respective upper 
`quadrants` of the profiled roller 1 with each roller 2, 3 being located 
at about 45.degree. around the upper surface of the roller 1 from the 
uppermost point thereof. The co-operating rollers 2, 3 are each 
independently adjustable in the direction of arrows 4, 5 relative to the 
profiled roller 1, in order to vary the degree of engagement with the 
roller 1. The outer surfaces of the co-operating rollers 2, 3 are spaced 
apart by a distance 6 in the transverse direction. A pressure roller 7 is 
guided in the direction of arrow 9 and is pressed against the co-operating 
rollers 2, 3 from above either under its own weight or under the action of 
external forces. The external diameter of the roller 7 is greater than the 
distance 6 between the outer surfaces of the co-operating rollers 2, 3. 
A web of material 10 travels through the width extending device 100 in a 
twisting manner, as shown in FIG. 1. Thus the web passes firstly through a 
nip 11 between the co-operating roller 2 and the pressure roller 7, then 
through a width-extending nip 12 between the co-operating roller 2 and the 
profiled roller 1. Then the web loops around the bottom part of the 
profiled roller 1 and passes through a second width extending nip 13 
between the co-operating roller 3 and the profiled roller 1 and then 
leaves the width extending device 100 after passing through a nip 14 
between the co-operating roller 3 and the pressure roller 7. To avoid 
warping, the web is guided through the device so that the angle .alpha. 
over which the web engages the bottom part of the profiled roller 1 is 
equal to the sum of the angles .beta. and .gamma. over which the web 
engages the co-operating rollers 2 and 3. 
In the region in which the incoming web 10 engages the co-operating roller 
2 and before the web 10 reaches the nip 12, the pressure roller presses 
externally against the web which is, of course, supported on the outer 
surface of the co-operating roller 2. The roller 7 has a relatively soft 
flat cylindrical coating 8 on its outer periphery (the coating having a 
hardness of approximately 60 Shore D). Similarly the pressure roller 7 
presses the web 10 against the co-operating roller 3 in the region where 
the web leaves the width-extending nip 13. 
In the embodiment shown, the rollers 1, 2, 3 are of approximately the same 
diameter and each roller has a uniform helical relief 15 formed in its 
periphery, as shown in FIGS. 2 and 3 for rollers 1 and 2. The arrangement 
is the same for rollers 1 and 3. 
In the embodiment of FIG. 2 the basic shape of the roller is substantially 
cylindrical and the helical relief 15 is in the form of an external rib 32 
which extends in a helix surrounding the roller body. The working width of 
the roller is approximately 2 m. The distance between adjacent turns of 
the helix, i.e. the axial distance from one rib peak to the next, is about 
15 mm, resulting in a total of about 130 rib peaks along the roller 
length. Thus FIGS. 2 and 3 are not shown to scale. 
The rollers 1 and 2 of FIG. 2 are of similar form having complementary 
reliefs formed in their periphery with the helical turns of the reliefs 
"engaging" as shown in FIG. 2. The rollers 1, 2 are designed to rotate 
relative to one another at the same speed without the flanks of the 
helical relief 15 coming into engagement. Thus, while reference may be 
made to the reliefs or the rollers engaging, it should be appreciated that 
there is no actual contact. There is instead `meshing` of the reliefs. 
During rotation of the rollers 1, 2 the width-extending nip 12 retains its 
corrugated shape and uniform width. 
FIG. 3 shows an alternative embodiment of a helical relief 15'. Each 
cylindrical roller 1, 2 has helical turns, extending outwards from a 
centre plane 16 which is perpendicular to the roller axis. The pitch to 
peak height S, i.e. the difference in radius between peaks 17 and troughs 
18 of the helix is constant on both sides of the plane 16, but the pitch 
on the two sides has opposite signs, that is to say the helical relief 15' 
starting from the centre plane 16 has a right hand thread on one side and 
a left hand thread on the other side. The relief 15' on the co-operating 
rollers 1, 2 in FIG. 3 are similar and engage in the manner shown in FIG. 
3 in that the peaks of the relief on roller 2 enter the troughs on the 
relief of roller 1. No contact occurs since this would result in damage to 
the web (which is not shown in FIGS. 2 and 3) guided in the space between 
the rollers. 
In the embodiments of FIGS. 2 and 3 the rollers 1, 2 can rotate relative to 
one another at the same peripheral speed, whereupon the helical reliefs 
15, 15' move to the side. This occurs in one direction in the FIG. 2 
embodiment and in both directions away from the centre plane 16 in the 
FIG. 3 embodiment. During this motion the point of engagement of the peaks 
of the reliefs on the web 10 changes in the lateral direction. The only 
purpose of the helical relief is to avoid longitudinal markings on the 
web. The helical shape of the reliefs 15, 15' is not essential for width 
extension. Also the helical reliefs 15, 15' do not transversely move the 
web 10. 
The width extension of the web depends upon the mutual depth of engagement 
E, E', as shown in FIGS. 4 to 6. 
If the web 10 were guided over the profiled roller 1 in FIG. 5 without a 
co-operating roller, then it would rest on the peaks 17 of the helical 
profile 15 (or 15') as indicated by the chain-dotted line 10 in FIG. 5. If 
the co-operating roller 2 is disposed opposite the profiled roller 1 in 
the nip 12 and the peaks 17' penetrate into the troughs 18 in the profiled 
roller 1 (as shown in FIG. 5), then the web 10 will no longer follow the 
chain-dotted imaginary course 10 but will follow the continuous line 
course 10' where the length of web in the width direction between the 
peaks 17 is increased, i.e., the web 10 has been stretched in the width 
direction between the peaks 17. When the peaks 17' penetrate into the 
troughs 18, the web 10 is held by friction against neighbouring peaks 17, 
producing forces which counteract the stretching forces. One important 
feature is that the stretching occurs between each pair of securing or 
retaining points constituted by the peaks 17. There are about 100 such 
points present along the length of the rollers 1, 2 or over the width of 
the web. 
The amount of stretching depends on the depth of penetration E of the peaks 
17'. In FIG. 6 the depth of penetration E' of peak 17 into trough 18 is 
less than in FIG. 5 and the web follows the course marked 10" which 
involves less stretching between the peaks 17. 
In the embodiment of FIGS. 4 to 6, the peaks 17 and the troughs 18 are in 
the form of arcs connected by tangential sloping surfaces 19, when 
considered in the longitudinal section through the axis of the roller. The 
angle between the sloping surfaces 19 on either side of one peak is marked 
21 in FIG. 6 and is equal to about 40.degree. . By way of example, FIG. 4 
also shows another possible embodiment in which the troughs and peaks 20 
(shown in dotted line) are in the form of semi-circles merging directly 
into one another. The peaks and troughs may, of course, take other forms 
and may be of mixed shapes. The radii of the troughs 18 are greater than 
the radii of the associated peaks 20 because, even at the maximum 
adjustment, a space must be left for the web between the rollers 1 and 2. 
If there was contact between the reliefs on the two rollers 1, 2 which 
co-operate to define the width-extending nip 12, the web would be damaged 
at the point of contact. 
FIG. 4 shows, approximately true to size, the helical relief used for a 
conventional textile web 10 of the kind in question. The longitudinal 
distance between the peaks 17 is about 15 mm and the peak height S is 
about 10 mm with the relief being provided on a roller about 2 m long. The 
helical relief can be turned in the periphery of a roll made of 
corrosion-resistant steel or may be formed by winding a suitably profiled 
wire onto the cylindrical body of the roller. Alternatively the helical 
relief 15 can be formed in a plastic coating for the roller. 
FIG. 7 shows an alternative relief shape 15" in which the ribs 17" and 
troughs 18" have a substantially rectangular cross-section in a plane 
passing through the longitudinal axis of the roller, the ribs 17" being 
narrower than the troughs 18". The ribs 17" are rounded at their outer 
edges so that the web follows the course identified by reference numeral 
10'". In the embodiment shown in the drawings, the flanks of the ribs, 
which are constituted by the longer sides of the rectangle, are at right 
angles to the roller axis. 
FIGS. 8 to 10 show examples of other types of relief which may be provided 
on the profiled roller 1 and the co-operating roller 2. In these examples 
the relief does not have a continuous peripheral rib. Instead, in FIG. 8 
the relief on the profiled roller 1 is constituted by `knobs` which extend 
in a straight line in both the longitudinal and in the peripheral 
direction, the knobs having a circular cross-section as seen in the radial 
direction and being of substantially conical shape. These knobs 36 engage 
between corresponding knobs 37 (shown by chain lines in FIG. 8) provided 
on the co-operating roller 2 so that a knob 37 on the co-operating roller 
always fits exactly between four knobs 36 disposed in a square on the 
profiled roller 1. In FIG. 9, knobs 38 are provided on the profiled roller 
1 which have a generally rectangular cross-section, the knobs having 
longitudinal sides which extend in the peripheral direction and which are 
in a line in the same cross-sectional plane. Adjacent knobs 38 in 
different cross-sectional planes lie on parallel straight lines which 
extend parallel to the roller axis. Corresponding knobs 39 (shown in 
chain-dotted lines) are provided on the co-operating roller and each knob 
39 lies between two adjacent knobs 38 in the longitudinal direction of the 
profiled roller 1. In FIG. 10 the relief is defined by helical grooves 
which form left-threaded troughs 18 and right-threaded troughs 18' so as 
to define diamond-shaped lands 18" which co-operate with a complementary 
relief, i.e. a helical relief, formed in a co-operating roller. This 
relief leaves many spaces between the lands 18" through which a liquid 
treatment medium may flow. 
It is to be appreciated that the terms `profiled roller` and `co-operating 
roller` denote a linguistic and not a functional distinction in this 
description. In practice the co-operating rollers are, of course, also 
profiled rollers and define a relief in their outer surface which is 
complementary to that defined in the surface of the profiled roller. 
Thus, the rollers 1, 2 which form the width-extending nip 12 are identical 
with one another and are interchangeable or are at least complementary. 
FIG. 11 shows an embodiment in which the width-extending device is 
additionally provided with spray devices 40, 41 for directing fluid 
treatment media, such as hot water or steam onto the web 10. The spray 
device 40 comprises a nozzle directed towards the web 10 at the point 
where it passes over the co-operating roller 2 before entering the nip 11 
defined with the pressure roller 7. The spray device 41 is a form of steam 
cone which is directed towards the profiled roller 1 at a position 
downstream of the width-extending nip 12. Directing steam onto the web 10 
at this position helps to relieve tension in the web 10. 
An additional pressure roller 7' may advantageously be placed in engagement 
with the profiled roller 1 at a position where the web 10 passes around 
the bottom part of the profiled roller just before the web enters the 
second width-extending nip 13. This additional pressure roller is shown by 
chain lines in FIG. 11. 
The embodiment of FIG. 11 also incorporates a batch-identification device 
52 which recognizes markings on the web 10 and delivers signals for the 
automatic adjustment of the width-extending nips 12, 13 upon recognition 
of the web markings. 
The co-operating rollers 2, 3 are designed to be positionally adjusted in 
the direction of arrows 4 to 5 so that the depth of engagement E of the 
co-operating roller 3 in the second nip 13 is greater than the depth of 
engagement E of the co-operating roller 2 in the first nip 12 so that the 
desired total width extension can be achieved in two stages. 
FIG. 12 shows a roller 1 having a helical profile 15' which corresponds to 
that shown in FIG. 3 and which, apart from the change in direction of 
rotation of the helical profile at the central plane 16, has uniform 
helical turns with a uniform peak height S across its width. In FIG. 12 
the edges of a web 10 are shown by broken lines and the web 10 is secured 
at its lateral edges on the roller 1 and on a co-operating roller by means 
of elastic rings. The resulting distribution of stretching 22 when the web 
passes through a width-extending nip made up of rollers 1, 2 of this type, 
is plotted in FIG. 12 for each position across the width of the web. It is 
found is practice that the stretching is at a minimum in the middle and 
increases substantially hyperbolically towards the edges. This 
distribution 22 of stretching is undesirable in many cases and results in 
higher mechanical stress in the more highly stretched regions and, for 
example, the capacity of the web to absorb dye fluid and the like may vary 
in dependence upon the stretch at a particular point, giving rise to 
noticeable differences in the colour shade of a finished web. 
The objective is to achieve a horizontal stretching distribution curve as 
shown at 23 in FIG. 13. In this case the specific stretching of the web is 
the same at any position across the width of the web. To this end the peak 
height S of the helical profile 15" on roller 1' in FIG. 13 is not 
constant as in FIG. 12 but continuously decreases from the centre of the 
roller towards the edges, resulting in a shape substantially as shown in 
FIG. 14. FIG. 14 is, of course a schematic representation of the helical 
relief at the surface of a roller 1' and a curve illustrating the 
variation in peak height S over the width of the web. In practice there 
would of course be many more peaks 17 in the helical relief. 
The pitch of the helical relief 15" in FIG. 13 is constant, but the peak 
height is greatest near the central plane 16 and decreases on either side 
thereof. Consequently the actual peripheral surface 33 of the roller 1' of 
FIGS. 13 and 14 fluctuates to some degree about an imaginary cylindrical 
surface indicated by a chain dotted line 24. 
It will therefore be appreciated that an opposed co-operating roller having 
the same construction or having a peak height corresponding to the maximum 
peak height in FIG. 14 will produce a greater depth of engagement in the 
middle of the roll than at the edges. The variation in peak height S 
across the width of the web is shown by the curve S' in FIG. 14 although 
it is to be understood that the curve S' may take a different form. In 
FIG. 13, for example, a corresponding line (shown as a broken line) 
illustrating the variation in peak height comprises two straight lines 
sloping down from the central plane 16 towards the edges of the roller. A 
depth of engagement varying over the length of the roller can also be 
achieved if the co-operating roller has a cylindrical outer surface. If 
however the outer surface is not cylindrical, as with the outer surfaces 
in FIGS. 13 and 14, then the pressure roller must fit the surface 
accordingly in order to produce uniform pressure across the web. 
With the arrangement of FIGS. 13 and 14, the web is stretched to a lesser 
degree at its edges than it is in the middle due to the reduced depth of 
engagement at the edges and this counteracts the stretching curve 22 shown 
in 26 FIG. 12. In the ideal case the distribution of stretching 23 is 
uniform across the web, as shown by the horizontal line in FIG. 13. 
FIGS. 15 to 18 show a modified embodiment of the width-extending device 100 
where the device comprises the same main components, that is to say the 
profiled roller 1, the co-operating rollers 2, 3 and the pressure roller 
7, but in this modified embodiment at least one of the rollers 1, 2 which 
form the width-extending nip 12 is perforated so that a fluid treatment 
medium can be sucked in or blown out therethrough. In FIG. 15 the 
perforation of the roller is not shown in the drawing. The area of 
engagement between rollers 1, 2 is, however, shown on an enlarged scale in 
FIG. 16. The ribs 32 which form the relief 15 on the rollers 1, 2 engage 
between each other. In the embodiment shown, through bores 44 extend into 
the rollers from the troughs between adjacent ribs 32 so that a fluid 
treatment medium can flow in and out of the roller. The bores 44 are 
uniformly distributed along the troughs 18. 
In the embodiment of FIG. 15 a non-rotatable duct 42 extends along the 
interior of the co-operating roller 2 and is directed radially outwardly 
towards the nip 12. As seen in FIG. 15, the rollers 1 and 2 are of hollow 
and thus each has an inner periphery or surface. The duct 42 is open in a 
narrow peripheral region directed towards the inner periphery of roller 2 
and is sealed at its edges. The duct 42 is connected to a pressure region 
D and steam or hot water or the like can be directed towards the inner 
periphery of roller 2 from where this medium flows out through the bores 
44 into the nip 12 and into the web 10 as it passes therethrough. 
A corresponding duct 43 is formed in the profiled roller 1 and has its 
opening disposed opposite the opening of duct 42. The duct 43 is connected 
to a reduced or negative pressure region V so that the medium introduced 
into the nip 12 via the duct 42 is sucked through the web 10 and the 
perforations 44 in roller 1 into the negative pressure region. In this way 
an intense flow is achieved through the web 10 at right angles to its 
plane as the web is extended in width within the nip 12. 
It is to be appreciated however that the arrangement illustrated in FIG. 15 
may be modified. Thus, only one duct 42, 43 need be provided and the duct 
need not be directed towards the nip 12. In addition, the pressure roller 
7 may be perforated and provided with means for conveying a fluid 
treatment medium. Alternatively the rollers 1, 3 could be provided with 
similar arrangements. 
FIG. 19 shows the width extending device 100 co-operating with a 
width-regulating device identified as a whole by a reference numeral 70. 
The width regulating device 70 comprises two detection units 45, 46 
disposed opposite one another at the opposed edges of the web 10 at 
positions where the web has exited the width extending device 100. In one 
embodiment the detection units may comprise optical units each having a 
row of diodes disposed at right angles to the edge of the web. 
Alternatively suitable mechanical sensors or similar devices could be 
used. The signals from the detection units 45, 46 are fed to a central 
regulating and control unit 48 in order for the actual value of the 
instantaneous web width to be evaluated. A control signal based on the 
actual value of the web width and a predetermined desired value is 
delivered to two force exerting units 49 which act on the journals 47 of 
each co-operating roller 2, 3 (the journals being illustrated 
diagrammatically in FIG. 19) in order to adjust the rollers in the 
direction of arrows 4, 5 (see FIG. 1) relative to the profiled roller 1. 
If the measured width of the web is too small then the depth of engagement 
E (see FIG. 5) between the rollers is increased by increasing the force 
supplied by the force exerting units 49 thereby maintaining a 
predetermined desired web width. 
Adjusting the stretching of the web by way of the depth of engagement E can 
be effected other than in the manner shown in FIG. 19. For example, the 
co-operating rollers 2, 3 can be adjusted in the direction of arrows 4, 5 
(see FIG. 1) by way of spindle drives which move the rollers to give a 
predetermined depth of engagement E. Alternatively, controllable force 
exerting units may maintain either a predetermined force or a 
predetermined depth of engagement (a predetermined engagement travel) in a 
controlled manner. 
In the embodiments thus far described the pressure element 7 has taken the 
form of a roller. FIG. 20 shows an embodiment in which the pressure 
element is in the form of a belt 77 which runs endlessly over guide 
rollers 73, 74, 75 which themselves extend parallel to rollers 1, 2 and 3. 
The belt 77 engages the web 10 over an arc in those regions where the web 
passes around the outer surface of the co-operating rollers 2, 3. This 
results in a considerable increase in the region over which pressure is 
applied by the pressure element, this region corresponding to the arc over 
which the belt engages the web rather than a point contact. This means 
that the web 10 can be more effectively held against the co-operating 
rollers 2, 3 over its width by smaller radial bearing forces. The web is 
therefore firmly supported over an extended region which may well be 
desirable when it is to be treated with liquid treatment media. The 
pressure belt 77 may have a smooth pressure surface or, alternatively, 
may, as with the pressure roller 7, have a surface relief on that side of 
the belt which is facing the web 10. As a further alternative the belt 77 
may be perforated. 
FIGS. 21 to 23 show various ways in which the width extending device 100 
may be used in practice. 
In FIG. 21 the bottom part of the rollers 1, 2 and 3 are disposed in a 
trough 26 which is filled to a level 27 with a treatment liquid 31. The 
trough has a double wall 28, 29 at the bottom, leaving a space 30 
therebetween in which a heat transfer liquid can circulate and indirectly 
heat the treatment liquid. In this manner, the web 10 has a short recovery 
period as it travels around the bottom part of the profiled roller 1, 
where it is impregnated with the treatment liquid. 
In FIGS. 21 to 23 a width-stretching device 35 is positioned immediately 
behind the width extending device 100 and pulls out and flattens the web 
10 which is slightly `crinkled` in the transverse direction upon leaving 
the width extending device 100. It will of course be recalled that the 
width-stretching device does not in fact increase the width of the web but 
merely smooths or flattens out the web. The downstream positioning of the 
width-stretching device 35 is important in order to avoid creasing of the 
web which may cause stoppages in subsequent downstream treatment stations. 
In the embodiment of FIG. 21 the width extending device 100 is disposed in 
front of a mangle identified by reference numeral 40 in which the 
treatment liquid 31 is squeezed out of the web. 
In the embodiment of FIG. 22 the width extending device 100 is disposed in 
front of a steam box 50 through which the web passes before passing 
through a mangle 40. 
In the embodiment of FIG. 23 the width extending device 100 is disposed 
within the casing of a steam box 60 adjacent the actual recovery section 
61 in the steam box. After leaving the steam box 60 the web 10 travels 
through a mangle 40 as in the embodiment of FIG. 22.