Modular construction pattern rolls for use in paper converting

The invention comprises a modular pattern roll for embossing a cellulosic fibrous structure. The pattern roll is made by assembling separate components, rather than being one piece and chemically etched according to the prior art. The pattern roll comprises a cylindrically perforate outer shell having radially extending protuberances inserted through the holes in the cylindrical shell. The protuberances are provided with an interference fit and/or, if desired, a shoulder at the proximal end to prevent the protuberances from being extruded and expelled through the hole and creating a missile hazard during operation. The center of the hollow cylindrically perforate shell is filled with a base roll and a radially expanding internal locking assembly, to prevent the protuberances from moving radially inwardly under the compressive forces which occur during operation.

FIELD OF THE INVENTION 
The present invention relates to modular construction pattern rolls having 
close tolerance radially extending protuberances and a close tolerance 
periphery between the radially extending protuberances. The pattern rolls 
are used in paper converting. 
BACKGROUND OF THE INVENTION 
Rolls used to convert, and particularly to emboss, cellulosic fibrous 
structures are well known in the papermaking art. Converting refers to any 
post drying operation which permanently affects any property of a 
cellulosic fibrous structure. Converting rolls typically have a pattern of 
radially extending protuberances which imparts the emboss pattern to the 
cellulosic fibrous structure. Each roll may be integral, or may be 
constructed from a plurality of components assembled in a particular 
configuration. 
A roll made from an integral assembly typically has the periphery of the 
roll, between the protuberances, chemically etched away, to leave only the 
radially extending protuberances unaffected by the etching process. The 
protuberances may then be machined to the final dimensions with a great 
deal of accuracy. 
However, such an etching process leaves the periphery of the roll between 
the proximal ends of the protuberances: out of tolerance with respect to 
straightness, concentricity, and diameter. Because this periphery of the 
roll is not a close tolerance surface and may be out of tolerance with 
respect to the foregoing parameters, the roll may be unsuitable for use in 
manufacturing which requires a great deal of accuracy at the roll 
periphery. 
Because the periphery of the roll is not a close tolerance surface, the 
periphery of the roll may be unsuitable for and hence is not used in the 
manufacturing process. This unsuitability represents a great waste, 
because, frequently, the periphery of the roll between the protuberances 
represents the majority of the surface area of the roll and the 
protuberances represent only a small percentage of the total surface area 
of the roll. 
Various attempts in the art to provide rolls constructed as an assembly 
have not been successful in overcoming this waste. For example, certain 
attempts in the art disclose magnetically attached flexible plates to the 
surface of an embossing roll. The plates may be removed and replaced as 
desired. Other attempts have utilized interference fits to assemble the 
components of the roll. Examples of such attempts in the art include U.S. 
Pat. Nos. 4,116,594 issued Sept. 26, 1978 to Leanna et al. and 4,705,711 
issued Nov. 10, 1987 to Perna. 
Also attempts have been made in the art to widen the compressive zone of 
the nip between rolls, or to permit deflection of rolls when a fabric 
passes between the rolls. The art further teaches coating the roll to 
achieve proper compliance and hardness. Yet other attempts in the art 
include a roll having a telescoping assembly which permits water to drain 
through. Examples of such attempts in the art include U.S. Pat. No. 
4,559,106 issued Dec. 17, 1985 to Skytta et al.; U.S. Pat. No. 4,856,159 
issued Aug. 15, 1989 to Skytta; U.S. Pat. No. 4,868,958 issued Sept. 26, 
1989 to Suzuki et al.; and the aforementioned U.S. Pat. No. 4,705,711 
issued Nov. 10, 1987 to Perna. 
However, none of these teachings overcome the problems of obtaining highly 
accurate protuberances in a roll with a close tolerance periphery between 
the protuberances. To achieve two close tolerance surfaces, the roll may 
be assembled from separate components. Each of the separate components may 
be machined to the desired tolerance prior to assembly. The prior art does 
not even teach how to assemble such a roll, even if close tolerance 
components were available. Furthermore, because the prior art has not 
utilized such a roll, the prior art does not teach the use of such roll to 
eliminate the waste which has heretofore been present without such close 
tolerance rolls being available. 
BRIEF SUMMARY OF THE INVENTION 
The invention comprises a roll for converting a paper laminate. The roll is 
a pattern roll and has a modular construction. The roll has a generally 
hollow cylindrically perforate outer shell with a plurality of radially 
oriented holes through this shell. A plurality of protuberances, each 
having a proximal end and a distal end, is provided. The protuberances are 
disposed in the holes so that the proximal ends are in engaged 
relationship with the shell and the distal ends of the protuberances 
protrude radially outwardly from the periphery of the shell. The roll 
further comprises a means for maintaining the protuberances and the 
cylindrically perforate shell in a fixed relationship. This means may 
comprise a radial anvil, such as is formed by a base roll used in 
conjunction with a radially expanding internal locking assembly.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to FIG. 1, a pattern roll 28 according to the present invention 
may be made with a modular construction having various components such as 
protuberances 30, a base roll 48, a cylindrically perforate shell 40 to 
dispose the protuberances 30 in a particular pattern, an inner shell 62, 
and an internal locking assembly 64 to maintain the protuberances 30 and 
the cylindrically perforate shell 40 in fixed relationship. The 
cylindrically perforate shell 40 has a plurality of holes 42 therethrough. 
The modular pattern roll 28 is provided with a plurality of protuberances 
30 which may, but does not necessarily, equal the number of holes 42. 
Each protuberance 30 is inserted through a hole 42 in the cylindrically 
perforate shell 40 in the cylindrically perforate shell 40 and secured in 
place by a means for maintaining the protuberances 30 and the 
cylindrically perforate shell 40 in fixed relationship. This means for 
maintaining the protuberances 30 and the cylindrically perforate shell 40 
in fixed relationship prevents the protuberances 30 from moving radially 
inward relative to the cylindrically perforate shell 40 or skewing from 
the radial direction. 
Referring to FIG. 2, a pattern roll 28 according to the present invention 
may be made of a modular construction, rather than as an integral 
component. The first component of the modular assembly is a cylindrically 
perforate shell 40. The outside of the cylindrically perforate shell 40 
provides the "periphery" of the pattern roll 28 intermediate the 
protuberances 30. 
The cylindrically perforate shell 40 may be made of any outside diameter 
desired, with a preferred diameter being about 40 to about 50 centimeters 
(16 to 20 inches), and for the embodiments described herein may have a 
diameter of about 45.4 centimeters (17.86 inches). The cylindrically 
perforate shell 40 has a radial thickness sufficient to withstand the 
stresses imposed by the embossing process described herein, and is 
preferably at least about 0.5 to about 1.0 centimeters (0.2 to 0.4 inches) 
in thickness, and for the embodiments described herein may be 0.8 
centimeters (0.3 inches) in thickness. 
For the embodiment described herein the cylindrically perforate shell 40 
may have an outside diameter of about 45.36 centimeters (17.860 inches) 
and an inside diameter of about 43.79 centimeters (17.240 inches). The 
cylindrically perforate shell 40 may be made of carbon or high nickel 
alloy seamless steel tubing and machined to a concentric, straight, 
constant diameter periphery 31 by means and equipment which are well known 
in the art and will not be described herein. 
By machining and, if desired, coating the periphery 31 of the pattern roll 
28, a close tolerance periphery 31 can be provided, as well as close 
tolerance protuberances 30 made in accordance with the description set 
forth below. As used herein a "close tolerance" surface is machined or 
otherwise formed to a tolerance of .+-.0.00008 millimeters (.+-.0.002 
inches). 
If desired, either the inside circumference or the outside periphery 31 of 
the cylindrically perforate shell 40 may be plated, coated, or otherwise 
finished as desired for purposes of hygiene, minimizing the attraction of 
foreign materials to the resulting pattern rolls 28 or to reduce 
corrosion. 
The cylindrically perforate shell 40 is open on at least one end, so that 
an axially oriented through-hole is present, making the cylindrically 
perforate shell 40 hollow. Additionally, the cylindrically perforate shell 
40 is provided with a plurality of radially oriented holes 42. The 
radially oriented holes 42 are disposed in a pattern and location 
corresponding to the pattern and location desired for the embossed sites 
of the resulting cellulosic fibrous structure. 
The holes 42 in the cylindrically perforate shell 40 may be of any size and 
shape desired, with the understanding that the shape of the holes 42 will 
influence the size and shape of the protuberances used therewith. The 
holes 42 in the cylindrically perforate shell 40 may be aligned in the 
machine and cross machine directions, unilaterally staggered, bilaterally 
staggered, or arranged in any pattern as desired to facilitate adhesive 
joining and the bond strength necessary for the consumer product during 
use. 
The disposition, size, and shape of the holes 42 are not critical, it is 
only important that each hole 42 in the cylindrically perforate shell 40 
be radially oriented and properly spaced from the adjacent holes 42. It is 
also not necessary that each hole 42 be equally spaced from the adjacent 
holes 42, but only that the pattern of the holes 42 be known and 
repeatable, so that proper registration between the two pattern rolls 28 
made according to this invention can be reliably achieved. 
For the embodiment described herein, the holes 42 and protuberances 30 may 
be disposed on a pattern oriented 45 degrees from the machine direction 
and bilaterally offset from the next protuberance about 2.23 millimeters 
(0.0876 inches) in both the machine direction and cross machine direction. 
The holes 42 in the cylindrically perforate shell 40 may be round, having 
a diameter of about 2.11 millimeters (0.082 inches) for the embodiment 
described herein. 
Referring to FIG. 3, the protuberances 30 used in conjunction with the 
modular pattern rolls 28 for the present invention are made from a single 
piece of steel through hardened to a hardness of at least Rockwell C 55 
and preferably at least Rockwell C 60. Alloy steel such as 4340 or 52100 
is suitable for the protuberances 30. If desired, the protuberances 30 may 
be made of a lower grade of steel and case hardened, although this process 
makes dimensional control more difficult. 
The shank of the protuberance 30 tapers intermediate the annular shoulder 
44 and the distal end 45 of the protuberance 30 at an included angle of 
about 26 degrees, measured from an imaginary apex beyond the distal end 45 
of the protuberance 30. At the base of each protuberance 30 is an annular 
shoulder 44 which at least partially circumscribes the protuberance 30. 
The shoulder 44 should be sized large enough so that the protuberance 30 
cannot pass through the holes 47 of the cylindrically perforate shell 40 
in the radially outward direction and become a missile hazard during 
operation. The shoulder 44 should be at least about 0.5 millimeters (0.026 
inches) greater than the diameter of the holes 42 in the cylindrically 
perforate shell 40 and have a thickness of at least about 2.5 millimeters 
(0.10 inches) to prevent the protuberances 36 from being extruded through 
the holes and creating such a missile hazard. 
The protuberances 30 should be sized in accordance with the holes 42 in the 
cylindrically perforate shell 40. During assembly, the protuberances 30 
are inserted through the holes 42 in the cylindrically perforate shell 40 
from the inside of the cylindrically perforate shell 40, so that the 
distal ends 45 of the protuberances 30 extend radially outwardly from the 
cylindrically perforate shell 40 and the shoulder 44 of the protuberance 
30 contacts and is in engaged relationship with the inside circumference 
of the cylindrically perforate shell 40. 
As illustrated in FIG. 3, the protuberances 30 may be provided with knurls 
43 to prevent the protuberance 30 from rotating about on its own axis. The 
knurls 43 provide a space intermediate the protuberances 30 and the 
cylindrically perforate shell 40 for adhesive, if desired, to join these 
components together. Prophetically, the knurls 43 :may be replaced by a 
plurality, such as three, circumferential grooves to provide a space 
intermediate the protuberances 30 and the cylindrically perforate shell 40 
for the adhesive. 
The shank of the protuberances 30 may have an interference fit at the 
knurls 43 of about 0.03 millimeters (0.001 inches). This interference fit 
temporarily holds the protuberances 30 in place while the means for 
maintaining the protuberances 30 and cylindrically perforate shell 40 in 
fixed relationship are installed and assembly of the pattern roll 28 is 
completed. 
If desired, the protuberances 30 may be permanently held in place by an 
interference fit and the annular shoulder 44 omitted. Such interference 
fit provides the means for maintaining the protuberances 30 and 
cylindrically perforate shell 40 in fixed relationship. 
For the embodiments described herein, to be used with paper toweling having 
two laminate and a basis weight as presented to the consumer of about 0.04 
kilograms per square meter (26 pounds per 3,000 square feet) and each 
lamina having a caliper prior to embossing of about 0.3 millimeters (0.012 
inches), the protuberances 30 should have an axial length, which extends 
radially beyond the periphery 31 of the cylindrically perforate shell 40, 
of at least about 1.3 millimeters (0.050 inches) preferably at least about 
1.8 millimeters (0.070 inches), and more preferably about 2.0 millimeters 
(0.080 inches), but not more than about 2.5 millimeters (0.100 inches). 
It is understood that slight adjustment from the foregoing dimensions may 
be necessary to accommodate a cellulosic fibrous structure of greater or 
lesser basis weight and caliper. However, with slight adjustments, the 
apparatus described herein can be used to manufacture a cellulosic fibrous 
structure having a basis weight of about 0.01 to about 0.07 kilograms per 
square meter (8 to 40 pounds per 3,000 square feet), and more preferably 
about 0.04 to about 0.05 kilograms per square meter (25 to 30 pounds per 
3,000 square feet). 
Protuberances 30 of this size help to insure sufficient deflection of the 
cellulosic fibrous structure occurs at the embossed sites and that a 
difference is apparent in the elevation between the embossed sites and the 
nonembossed region of the laminae. This arrangement may yield a cellulosic 
fibrous structure having caliper of about 1.0 millimeters (0.040 inches) 
and a greater depth between the midpoint of the span and the embossed 
sites than can be achieved under like conditions utilizing the prior art. 
The distal ends 45 of the protuberances 30 may have an area of about 0.01 
square centimeters (0.002 square inches) with the understanding that it 
will produce embossed sites having a like area. For the embodiments 
described herein, the protuberances 30 and distal ends 45 thereof may be 
circular in cross section and round respectively. However, it is 
understood that protuberances 30 of other cross-sections and distal ends 
45 which are not circular may be advantageously used with the present 
invention. 
After the protuberances 30 are inserted through the holes 42 in the 
cylindrically perforate shell 40, a means for maintaining the 
protuberances 30 and the cylindrically perforate shell 40 in fixed 
relationship must be provided. The means for maintaining the protuberances 
30 and the cylindrically perforate shell 40 in fixed relationship prevents 
the protuberances 30 from moving radially inwardly under the compressive 
forces present in and during the manufacturing process and which forces 
are caused by the compression of the distal end 45 of the protuberance 30 
against the periphery 31 of the other pattern roll 28 at the proximal end 
of the protuberances 30 of that pattern roll 28. 
One preferred means for maintaining the protuberances 30 in the 
cylindrically perforate shell 40 in fixed relationship is a radial anvil. 
As used herein a "radial anvil" refers to any structure or fixture which 
transmits the radial forces through the protuberances 30 to the mounting 
for the pattern roll 28. As is well known in the art, the pattern roll 28 
may be mounted on both ends of its shaft, may be cantilevered, may be 
trunnion mounted, and provided with journals, bearings, or other means to 
allow the pattern roll 28 to axially rotate while maintaining the desired 
axially parallel relationship, position, and clearance with the other 
pattern roll 28B. 
As illustrated in FIG. 1, one advantageous execution of a radial anvil 
which provides a satisfactory means for maintaining the cylindrically 
perforate shell 40 and protuberances 30 in fixed relationship comprises a 
central base roll 48, and an inner shell 62. The base roll 48 and inner 
shell 62 both are mutually concentric and each have a constant inner 
diameter, a constant outer diameter, and a constant radial thickness. 
Examining the assembly of the foregoing components in more detail, the 
inner shell 62, for the embodiment described herein, may be made having an 
outside diameter of about 43.34 centimeters (17.063 inches) and an inside 
diameter of about 42.50 centimeters (16.734 inches). The proximal ends or 
shoulders 44, if provided, of the protuberances 30 define a circle having 
a smaller diameter, particularly a diameter of about 43.33 centimeters 
(17.060 inches), and therefore an interference fit is present. 
To overcome this interference fit caused by the difference in size between 
the inner shell 62 and the circle defined by the insides of the 
protuberances 30 and to aid in assembling the inner shell 62 to the 
pattern roll 28, the inner shell 62 is thermally contracted. Cooling the 
inner shell 62 reduces its diameter, due to the associated thermal 
contraction. For the embodiments described herein a temperature 
differential of at least about 77.degree. C. (170.degree. F.) has been 
found suitable. 
After the inner shell 62 is cooled it is inserted into the subassembly 
comprising the protuberances 30 and the cylindrically perforate shell 40. 
The inner shell 62 is allowed to warm to the ambient temperature and a 
press fit of about 0.08 millimeters (0.003 inches) is formed. This press 
fit maintains the protuberances 30 in fixed relationship relative to the 
inner shell 62 for the balance of the assembly of the pattern rolls 28. 
However, this arrangement does not yet adequately transmit forces radially 
applied to the protuberances 30 to the mounting for the pattern rolls 28. 
The constant diameters and thickness base roll 48 and inner shell 62 must 
be joined to one another by a component. 
One suitable component to join the base roll 48 and inner shell 62 and 
transmit the radial load therebetween is an annular collar. A simple 
annular collar may be of constant internal and external diameter and 
constant radial thickness. The annular collar may be sized to provide an 
interference fit between the base roll 48 and the inner shell 62, and may 
be axially inserted therebetween using a hydraulic press as is well known 
in the art. 
A particularly preferred annular collar is radially adjustable in 
thickness. While many annular collars may be suitable and used in the art, 
one component which is radially adjustable and has been used with success 
is an internal locking assembly 64. An internal locking assembly 64 may be 
inserted into the annular space between the base roll 48 and the inner 
shell 62 in a loose condition, then tightened using the axially oriented 
threaded fasteners 66 commonly supplied and associated with such internal 
locking assemblies 64 to radially expand the internal locking assembly 64. 
The locking assembly 64 should be sufficiently sized to transmit the torque 
from the drive unit through the base roll 48 or whatever component of the 
pattern roll 28 which is connected to the drive unit, to the inner shell 
62 and eventually to the cylindrically perforate shell 40 without inimical 
angular deflection therebetween. A self-centering internal locking 
assembly 64 has been found advantageous, as it is important that 
concentricity be maintained in the modular pattern rolls 28. A Series 303 
size 340.times.425 self-centering internal locking assembly 64 sold by the 
Ringfeder Company of Westwood, N.J., has been found suitable for the 
embodiments described herein. 
If the pattern of the protuberances 30 is sparse enough or axially short 
enough, or, alternatively, the internal locking assembly 64 is axially 
long enough, the inner shell 62 may be omitted. In this embodiment, the 
internal locking assembly 64 still provides the means for maintaining the 
protuberances 30 and cylindrically perforate shell 40 in fixed 
relationship. 
Referring to FIG. 4, a less preferred means for maintaining the 
protuberances 30 and the cylindrically perforate shell 40 of the pattern 
roll 28' in fixed relationship is a hardenable resin 68 which fills the 
inside of the cylindrically perforate shell 40. The resin 68 may be 
poured, in liquid form into a vertically disposed cylindrically perforate 
shell 40 having the protuberances 30 installed from the inside, and 
allowed to harden. Once hardened, the resin 68 solidifies and prevents the 
protuberances 30 from moving radially inwardly, or from rotating about its 
axis. 
Suitable resins 68 include epoxy type polymers. A particularly suitable 
resin 68 is sold by the Conap Company of Olean, N.Y., under the model 
number TE-1257, and used with EA-116 hardener. 
If this means for maintaining the cylindrically perforate shell 40 and 
protuberances 30 in a fixed relationship is selected, the pattern roll 28' 
may be further provided with a base roll 48, so that the amount of resin 
68 necessary to hold the protuberances 30 and cylindrically perforate 
shell 40 in fixed relationship is minimized. A hollow or solid cylindrical 
base roll 48 having a diameter slightly less than that defined by the 
proximal ends of the protuberances 30 may be installed and centered in the 
cylindrically perforate shell 40 after the protuberances are installed. 
The resin 68 is poured in the annular space 50 between the base roll 48 and 
the cylindrically perforate shell 40. This arrangement provides the 
advantages of reducing the total amount of resin 68 used, which frequently 
has a lower modulus in compression than either the base roll 48 or the 
cylindrically perforate shell 40, and provides for economization of 
manufacture and reduces the sensitivity of the cure time to factors 
affecting the hardness of the resin 68 after curing. 
It is understood that one disadvantage to this means is the protuberances 
30 may embed in the resin 68, reducing their radial protrusion from the 
periphery 31 of the pattern roll 28'. This embedment can be compensated 
for by longer protuberances 30. 
Another less preferred means for maintaining the cylindrically perforate 
shell 40 and the protuberances 30 in fixed relationship is the base roll 
48 used to fill the cylindrically perforate shell 40 having the 
protuberances 30 installed through the holes 42 from the inside of the 
cylindrically perforate shell 40 used without resin 68. In this 
arrangement, the outside diameter of the base roll 48 is slightly larger 
than the inside diameter defined by the proximal ends of the protuberances 
30. A press fit or interference fit arrangement then occurs, so that the 
proximal ends of the protuberances 30 impart radially compressive stresses 
to the base roll 48. 
An interference fit may be advantageously accomplished through thermal 
contraction of the base roll 48. However, one disadvantage of this 
arrangement is that disassembly and reuse of the individual components of 
the pattern roll 28 is typically difficult to accomplish. Thus, for 
example, if one of the protuberances 130 were broken, it may be infeasible 
to replace just the broken protuberances 30 (a problem indigenous to the 
integral pattern rolls of the prior art), and the pattern roll 28 may have 
to be scrapped. The base roll 48 is cooled, axially inserted in the 
cylindrically perforate shell 40 and warmed to ambient temperatures so 
that exposure to the final dimension may occur. 
If desired, the axial ends of the cylindrically perforate shell 40 may be 
provided with a means for registering 65 the cylindrically perforate shell 
40 with other cylindrically perforate shells juxtaposed in axially 
contiguous relationship therewith. The means for registering 65 the 
cylindrically perforate shells 40 of axially juxtaposed and contiguous 
pattern rolls 28 provides for continuity of the aesthetic pattern formed 
by the protuberances 30 across the consumer product. 
This arrangement allows a plurality of pattern rolls 28 to be axially 
concatenated, so that in manufacture a cellulosic fibrous structure of 
greater width can be advantageously constructed. Particularly, this 
contributes to more economical manufacture of such a cellulosic fibrous 
structure. 
One suitable means for registering 65 the cylindrically perforate shell 40 
of a pattern roll 28 to another cylindrically perforate shell 40 of an 
axially contiguous pattern roll 28 is irregularities in the axial ends of 
the cylindrically perforate shell 40. 
Particularly, the axial ends of the cylindrically perforate shell 40 may be 
provided with scallops as illustrated, may be serrated or provided with a 
saw-tooth or square wave pattern. The exact size, shape, distribution, and 
position of the irregularities will depend upon the particular aesthetic 
pattern of the protuberances 30. 
If desired, other patterns may be made in the pattern rolls 28 which will 
conform to like patterns of embossed sites and nonembossed regions in the 
cellulosic fibrous structure. For example, instead of discrete embossed 
sites and an essentially continuous nonembossed region, the pattern rolls 
28 may be provided with an essentially continuous protuberance network. 
Prophetically this essentially continuous protuberance network may be 
provided by having a cylindrical shell of the proper radial wall 
thickness, and drilling blind holes into the outside of the cylindrical 
shell. The blind holes will not compress the coincident regions of the 
respective lamina against the other lamina in the nip formed by the 
pattern rolls 28. This arrangement produces a cellulosic fibrous structure 
having an essentially continuous embossed site and discrete nonembossed 
site. 
In use, two pattern rolls 28 may be juxtaposed in axially parallel 
relationship to form a nip therebetween. The protuberances 30 of these 
pattern rolls 28 may be sized so that the distal end 45 of each 
protuberance 30 touches the periphery 31 of the opposing pattern roll 28 
between its protuberances 30. 
Two embossed laminae to be joined together are interposed in the nip 
between the two pattern rolls 28. In this arrangement, the cellulosic 
fibrous structure is in contacting relationship with not only the 
protuberances 30, particularly the distal ends 45 of such protuberances 
30, of a particular pattern roll 28, but is also in contacting 
relationship with the periphery 31 of such pattern roll 28. As used 
herein, two components are considered to be in "contacting relationship" 
if the components are touching and held together by compressive forces 
applied thereto. 
This contacting relationship provides the advantage that not only do the 
protuberances 30 participate in and influence the embossing, or other 
converting operation, particularly adhesive joining, of the cellulosic 
fibrous structure--but also the periphery 31 of the pattern roll 28 may be 
utilized in the converting operation. The cellulosic fibrous structure is 
compressed, and hence densified, at each site in the nip where the 
cellulosic fibrous structure is in contacting relationship with the distal 
end 45 of a protuberance 30. Such compression facilitates adhesive joining 
of the laminae at these sites. 
Furthermore, the portion of the cellulosic fibrous structure in contacting 
relationship with the periphery 31 of the pattern roll 28 is compressed or 
embossed by the protuberance 30 of the opposing pattern roll 28. This 
operation allows the cellulosic fibrous structure to be uniformly and 
equally embossed on both sides, so that a particularly pleasing aesthetic 
appearance is not present on just one side of the cellulosic fibrous 
structure. 
Several variations to the foregoing are contemplated by the present 
invention. For example, generally, it is preferred that the two pattern 
rolls 28 be of equal diameter and have the same size (cross sectional area 
and radial length) protuberances 30. However, if desired, the 
cylindrically perforate shells 40 of the pattern rolls 28 may have 
different outside diameters, or, alternatively, the protuberances 30 of 
the two pattern rolls 28 may have different spacings and patterns between 
adjacent protuberances 30. If desired, the pattern rolls 28 may be heated 
by means well known in the art. 
It will be apparent that there are many other variations within the scope 
and intent of the claimed invention, all of which are covered by the 
appended claims.