Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Background of the Invention
This invention relates to a method and apparatus for
expanding the width of a preformed fibrous web; and, more
particularly, for expanding the width while maintaining original
lengthwise fiber orientation and/or controlling the web profile.
Nonwoven webs of fibrous materials and nonwoven
fabrics are commercially important materials in the textile and
related industries. Nonwoven webs are formed from textile
fibers or so-called "staple" fibers, such as cotton, wool,
wood, jute, viscose rayon, nylon, polyester, or other materials
varying in length from about 1/4 inch to about 2 or more
inches. Such fibers are processed through conventional textile
machinery. For example, a carding machine may be used to form
a continuous length of rather two-dimensional, loosely
associated fibers known as a carded web. These webs may be
assembled to form a multiple layer or three-dimensional fibrous
web of significant weight, e.g., from about several hundred
grains to thousands of grains per square yard.
In continuous nonwoven fibrous webs, the textile
¦ fibers are arrayed at various angles to the lengthwise axis
~of the web. Depending upon processing techniques, the fibrous
¦Iwebs may be oriented, that i5 parallelized, or isotropic. When
¦¦a web is formed by the action of a carding machine, the fibers
iiare usually predominantly oriented in the machine direction,
i.e., the lengthwise axis of the fibrous web, which is the
¦Idirection in which a web is formed and is moved continuously
¦and assembled with other webs of similar fiber orientation.
¦On the other hand, isotropic webs may be formed such as by
air-laying.
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Carding or air-laying machines produce soMewhat
standardized fibrous web widths and it becomes necessary usually
at some stage in processing to vary these widths either simply
to obtain a particular width or for the purpose of efficiency,
. among other purposes. Many apparatuses and methods are known
to the art for expanding the width of anonwoven fibrous web
including the use of bowed rollers, springs, cross-stretching
belts, diverging disks, and the like. All of these appara-tuses
and methods have disadvantages including among other things
the need for complicated and expensive equipment, the inability
to expand the width of the web without either altering the
orientation of the fibers or weakening the web, and the
inability to control and change the profile of web, i.e., the
thickness, uniformity, and weight of the web across its width.
Summary of the Invention
This invention consists of a unique method and
apparatus for expanding the width of preformed fibrous webs.
The invention overcomes a number of problems heretofore
associated with the prior art techniques mentioned above. In
accordance with the principles of the invention, a continuous
length of a preformed fibrous web is bent over the edge of a
blade lying at an angle to the direction of web travel whereby
both the direction of web travel and web fibers are abruptly
¦ changed to expand the web width. Furthermore, according to
¦ this method, original webs having a predominant fiber orientation
can be maintained in such orientation during expansion. In
¦ another of its features, this invention provides a method and
¦~ means to control and change the profile of preformed fibrous
j~ webs in a simple manner without web rupture and without the
~ need for ratller expensi~e or co~licated equlpment.
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In its general aspect, this invention provides a method
for expanding the width of a continuous length of preformed
fibrous web comprising the steps of moving the web in a length-
wise direction, feeding the web to a blade having an edge,
at least a portion of the edge lying at an angle to the length-
wise direction, abruptly changing the direction of travel of
the web at the edge from the lengthwise direction to a second
direction, turning the web fibers in the second direction while
expanding the width, and taking the web having an expanded
width off the edge in the second direction.
Another aspect of the present invention provides an
apparatus for expanding the width of a continuous length of
preformed fibrous web comprising at least one blade having an
edge, means for moving the web in a lengthwise direction at an
angle to at least a portion of the edge, and means for abruptly
changing the direction of travel of the web at the edge from
the lengthwise direction to a second direction and turning the
web fibers in the second direction while expanding the width.
This invention is thus in contrast to prior art methods
of the type disclosed in U.S. Pats. Nos. 2,594,591; 2,618,012;
2,758,048; 2,952,893; 3,303,547 and 3,708,831 which involve
methods and apparatus for spreading webs by such aforementioned,
complicated means. Furthermore, while it has also been known to
doff fibers from a cylinder at an angle thereto to change fiber
orientation in the manufacture of a loose web as disclosed in
U.S. Pat. No. 3,066,359, the present invention is directed
; to preformed fibrous webs of three-dimensional form. Also,
the latter mentioned patent does not involve abruptly changing
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directions and simultaneously turning fibers duriny expansion,
let alone by simplified means employed herein. Also, according
to this invention, webs having a predominant fiber orientation
can be expanded and because, abruptly at the turning blade,
the fibers are turned in the new direction, the expanded web
has the same predominant fiber orientation as the original
web. The method of this invention therefore permits expanding
¦ the width of a continuous length of preformed fibrous web
¦ without altering the predominant fiber orientation of the
I web while eliminating complicated machinery and web hold down
¦ devices.
In a preferred form of the invention, the web com-
prising multiple layers is bent over the edge of a blade lying
at an angle to the conveyor carrying the web and the direction
of web travel is abruptly changed to a second direction
generally perpendicular to the plane of the conveyor and the
plane of original web travel. That is, for example, if the
unexpanded web were traveling on a horizontal conveyor in
the lengthwise direction, the direction of web travel is
abruptly changed at the blade edge to generally a vertical
plane. The web fibers are thereby locked at the blade edge
and turned over the edge to the new direction of web travel.
The fibers which are parallel or at a zero angle of orientation
with respect to the free edges of the original web are turned
and maintained in the predominant orientation when turned
over the edge of the blade and in the new direction. Those
fibers which are ~t an angle to the free edges of the original
web are, depending upon the blade angle, either maintained
or oriented to a greater degree in the new direction.
A further object of this invention is to provide a
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method and apparatus which permits the control of the profile
of the web material being handled on the web machinery, i.e.,
the thickness, uniformity, weight and fiber density of the
web across its width. In a preferred form of this aspect of
the invention, a blade is employed having an edge comprising
multiple angles whereby portions of the edge lie at different
angles with respect to the direction of travel of the original
web. Proper selection of the angles of the blade edge permits
control of the profile of the web material being expanded.
The method includes the steps of moving the preformed fibrous
web on a conveyor in the lengthwise direction, feeding the web
to the blade edge, and abruptly changing the direction of
travel of the web at the edge with the web bending over the
multiple angulated edge portions of the blade. The angle of
the fibers and web travel changes to a direction generally ;~
perpendicular to the conveyor. The web is taken-off the edge
at a speed greater than or at least equal to the velocity of
the web prior to entering the angulated blade area. The degree
of expansion of the web across its width varies in conformity
with the angulated portions of the blade edge. This invention
thus permits a web profile to be altered to a desired, con-
trolled profile. Prior art methods do not provide for such
profile control of a preformed fibrous web by so expanding a
portion or distinct portions of the web across its width.
This invention further admits of the use of a plurality
of consecutively arranged expanding areas whereby a preformed
fibrous web may bc sequcntially expandcd in a continuous web
forming operation.
These and other advantages of this invention will
be further ppreciated by reFer-~c to the follo~ing detailed
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description and accompanying drawings.
Brief Description of the Drawings
Fig. 1 is a schematic elevational view illustrating
an apparatus in accordance with the principles of the method
of this invention for expanding the width of a continuous length
of preformed fibrous web;
Fig. 2 is a view taken along line 2-2 of Fig. 1,
Fig. 3 is a view taken along line 3-3 of Fig. l;
Fig. 4 is a developed view of the web illustrated
in Fig. l;
Fig. 5 is a schematic elevational view of a blade used
in one embodiment of this invention; and
Fig. 6 is a top view of Fig. 5.
, Detailed Description of the Invention
Referring to Fig. 1, the apparatus includes a first
conveyor 10, a first blade having an edge 12, a second conveyor
14, a third conveyor 16, a second blade having an edge 18,
and a take-off conveyor 20.
A continuous length of preformed fibrous web 22 is
carried on the moving surface of the conveyor 10 toward the
first blade in a direction A. The source of supply of the web
is not critical. For example, the web may come from a supply
roll or from an adjacent upstream web-forming operation, e.g.,
conventional carding or air-laying, in a continuous web forming
and expanding operation. The web may be formed of multiple
two-dimensional layers assembled together. Where conventional
carding operations are employed, the predominant fiber orien-
, tation resulting from the web forming operation is in the machine
direction A.
~ ng the Eirst conve-o 10 is disposed the first
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blade which is formed of suitable material such as sheet metal
to have a flat surface which rides against web 22 as it is
carried on the conveyor 10 and which terminates in a free edge
12. The blade is so disposed that the edge 12 lies at an
angle to the direction A of web movement. This angle is
predetermined and is calculated by the degree of width expansion
desired. As shown in Fig. 2, edge 12 there illustrated lies
at a 45 angle with respect to the moving web direction A.
The blade is held in a stationary position at the end 24
opposite the free edge by means not shown.
At the blade edge 12 the traveling web 22 is abruptly .
turned from its lengthwise direction of travel, A, to a new
direction s which lies on a plane perpendicular to the plane of
the web moving in direction A. Although exact perpendicularity
is not required, it is generally desirable because of the
necessity to lock the web fibers at the blade edge and turn
them into the new direction B to maintain the predominant
lengthwise fiber orientation in the expanded web.
The width of the web 22 is expanded along the edge
12 to a width equaling about the length of the edge 12. The
direction of web travel changes from direction A to B. However,
the predominant fiber orientation is maintained. The fibers
which are parallel or at a zero angle of orientation with
respect to the free edges of the original web are turned and
maintained in the predominant orientation when turned over the
edge of the blade and in the new direction of web travel, B.
The web is taken off the edge 12 by the second conveyor
14 at a speed greater than or at least equal to the speed of
the web on conveyor 10. If the original web is at its desired
expanded wi h aiter passinlg ove the blade edge 12 the expanded
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web can continue in the direction B directly to and onto the
take-off conveyor 20 to be rolled or transferred to a downstream
processing step. The conveyors 14 and 16 are employed when it is
desired to further expand the web width. In this case, the web
22 is fed to a second blade on vertically spaced conveyors 14
. and 16 so oriented with respect to the conveyor 10 that the
directions of web travel C and D respectively are perpendicular
to blade edge 12.
Referring to Fig. 3, the second blade is identical
in construction to the first blade and terminates in the free
edge 18. The blade is so disposed that edge 18 lies at an angle
to the movement of the web 22 on the conveyor 16 in the direction
D. In Fig. 3, this angle is illustrated as 45~. At the second
blade edge 18, as described in relation to the first blade, the
traveling web is abruptly turned from its direction of travel,
D, to a new direction E which lies in a plane perpendicular to
the plane of the web moving in direction D. In practice, the
web will move in generally horizontal planes in directions A,
C and D and in vertical planes in directions B and E.
The width of the once-expanded web is again expanded
along the edge 18 to a width equaling about the length of edge
18. Again the direction of web travel changes abruptly from
direction D to E, and the fibers are turned over the blade
edge to maintain the lengthwise fiber orientation.
The web 22 is taken off the edge 18 by the take-off
conveyor 20. Conveyor 20 so disposed that the direction of web
travel F on the conveyor is perpendicular to the blade edge 18.
Conveyor 20 is vertically displaced from conveyor 10 but is in
line therewith such that the expanded web can exit the expanding
3- apparatus o the same line on w`~h it entered allowing for
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convenient arrangement of the apparatus in a continuous web
forming and expanding line.
Referring now to Fig. 4, the amount of expansion of
the web is a function of the angle at which the blade edge lies
to the direction of travel of the web at the edge. The increase
in width of the original web from Wl to W2 at blade edge 12 is
calculated as follows: W2 equals Wl divided by the cosine of .~?
the angle of the blade to the direction of travel, A. In Figs.
1 and 2, the blade has been illustrated as lying at a 45 angle
to the direction of travel of the web, A. Accordingly, if Wl
were 45 inches, W2 would equal 63.63. Likewise in Figs. 1 and
3, blade edge 18 has been illustrated as lying at an angle of
45 to the direction of web movement D. Thus, width W2 of
63.63 inches is expanded at edge 18 to a width W3 equaling
89.97 inches. In the apparatus illustrated in Fig. 1, the
blades may conveniently be mounted so that they can be rotated
to change the angle at which they lie with respect to the
conveyors to accomplish different amounts of web expansion,
as desired.
Referring now to Figs. 5 and 6, there is shown a
blade 30 for expanding the width of a continuous length of
preformed fibrous web 22 in accordance with the principles of
the method of this invention and, simultaneously, altering
the profile of the web. The blade 30 is in the shape of a V
which includes an edge 32 formed of four portions: 32a extending
between points a and b; 32b, extending between points b and c;
32c, extending between points c and d; and 32d, extending between
points d and e. Portions 32a and 32b and 32c and 32d are
symmetrical about the centerl~ne 34 of the web 22.
; 30 The blade 30 is held stationary in the web expanding
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operation by securing the end 36 such that the flat surface of
the blade rides on the web 22 moving in the direction A on the
conveyor 10, and edge 32 presents a free edge abou~ which
the web is turned. Edge portions 32a and 32d lie at an angle
to the direction A of web travel, and edge portions 32b and 32c
lie at a greater angle to the direction of travel. Thus the
degree of expansion of the web will be greater over portlons
32b and 32c than over 32a and 32d. This results in an alteration
of thickness, weight, and fiber density across the web in its
widthwise direction to produce either a non-uniform cross-section
or uniform cross-section depending upon the result desired and
the profile of the original web. By proper selection of the
angles of orientation of the blade edge portions, the web can
be expanded in any number of distinct directions to give a
desired, controlled distribution of fibers across the width of
the web. The V-shaped blade shown in Figs. 5 and 6 is merely
illustrative, and blades of other symmetric or asymmetric shapes
may be employed to give a desired web profile.
The method is identical to that described in relation
¦ to Fig. 1. The preformed fibrous web 22 having a predominant
lengthwise fiber orientation is moved on the conveyor 10 in the
lengthwise direction A toward the blade 30. The web 22 is
unrestrained on the conveyor 10. At the blade edge 32 the
direction of travel of the web is abruptly changed to a new
direction B which lies in a plane perpendicular to the plane
of the web moving in direction A. The web bends over the
multiple an~ulated blade edge portions, and the web fibers
are locked and turned into direction B. The web is expanded
more at edge portions 32b and 32c than at 32a and 32d, and the
~ total expanded width, S, is the sum of these individual ex-
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pansions. Where the original web fibers are generally parallelly
oriented, the predominant fiber orlentation is maintained.
The web is taken off edge 30 by either conveyor 20, or conveyor
14, if the now profiled web is to be fed to a second blade. The
speed of take off is greater than or at least equal to the speed
of the web on conveyor 10.
Having described this invention and its presently
contemplated best mode, it will become apparent to those of
ordinary skill that obvious variations may be made in view of
the above description to obtain the benefits thereof.
What is claimed is:
