Textiles: fiber preparation – Assembling – Formed web
Reexamination Certificate
1999-08-19
2001-02-20
Calvert, John J. (Department: 3741)
Textiles: fiber preparation
Assembling
Formed web
C019S161100
Reexamination Certificate
active
06189185
ABSTRACT:
The Present invention relates to a method of producing a fibre fleece having a non-uniform thickness profile.
The present invention also relates to a method for producing a continuous textile product having a non-uniform transverse profile.
The present invention also relates to a crosslapper device and a device for producing a continuous textile product for implementing this method.
In order to produce a fibre fleece, intended in general for subsequent processing, in particular a process of consolidation by needling, it is known to use a crosslapper whose function is to produce a zig-zag folding, on an output conveyor, of a web composed of longitudinal fibres.
In this machine, the web is disposed in segments, alternately inclined in one direction and then in the other, which overlap one another. The folds between segments are aligned along the lateral edges of the fleece produced.
Such a fleece generally has a uniform thickness profile over its entire width. FR-A-2 234 395 gives the speed relationships to be complied with in the crosslapper in order to control the thickness of the fleece. According to EP-A-0 315 930, the fleece can have a variable thickness profile by varying the speed of the carriage, which deposits the web on a variable point in the width of the output conveyor belt, with respect to the speed of the conveyor belts which carry the web up to this carriage. If, at a given position in the width of the fleece, the carriage moves at a speed greater than that at which it feeds the web, the web is stretched and this reduces the thickness of the fleece at that place. If, on the contrary, the speed of the carriage is less than the feed speed, the web is deposited in a compressed form which increases the thickness of the fleece at that place.
This method of profiling the fleece has certain limitations. The stretchings and compressions of the web cannot be positioned accurately because there is a distance between the place at which the web leaves the carriage and the place at which it is deposited on the output conveyor. Furthermore, particularly with certain types of fibres, the tensile or compressive stresses imposed on the web tend to be transmitted to certain regions of the web deposited just before or just after the zone for which a predetermined tension or compression is desired. Finally, the tension or compression imposed on the web cannot exceed certain limits without risks.
The documents DE-C-100 658 and DE-A-195 27416 describe methods in which two successive crosslappings are performed. For avoiding that the longitudinal edges of the first fleece form transverse edges on the second fleece, said longitudinal edges are realized as bevelled edges. Therefore, some of the folds between segments of the first crosslapping are slightly offset sidewardly inwardly of the first fleece. The purpose of this arrangement is to obtain a final textile product having a uniform longitudinal profile. The product resulting from the second crosslapping has a uniform transverse profile.
The document DE-A-42 34 354 discloses the deposition of elementary fibre webs, thereby to imbricate the elementary webs with respect to each other. The result is a reduced thickness and weight per unit of area along the edges, which have to be eliminated by a cut, designated by the reference letter “T”, whereby the product which is thereafter subjected to needling has a uniform transverse profile.
The purpose of the present invention is to propose a method and a device for producing more efficiently a fibre fleece and a continuous textile product having a non-uniform, in particular stepped thickness profile and/or profile of weight per unit of area over the width of the fleece.
According to a first aspect of the invention, the method of producing a fibre fleece by depositing on an output conveyor successive transverse segments of web connected to one another by folds produced alternately in one direction and then in the other by reversal of the transverse direction in which the web is deposited, wherein there is positioned at different locations in the width of the output conveyor at least certain of the successive folds of the same direction, is characterized in that folds positioned along at least one line located between side edges of the fleece form a shoulder between two longitudinal zones of the fleece.
According to a second aspect of the invention, the method of producing a continuous textile product provided with a transverse profile having a non-uniform thickness, comprising the step of forming a fibre fleece by depositing on an output conveyor successive transverse segments of web connected to one another by folds produced alternately in one direction and then in the other by reversal of the transverse direction in which the web is deposited, wherein there is positioned at different locations in the width of the output conveyor at least certain of the successive folds of the same direction, is characterized in that the non-uniform profile of the fibre fleece is substantially kept along a transverse direction of the continuous textile product until the end of a subsequent step of consolidation.
The term “amplitude” of a segment will refer to the distance between the two folds delimiting that segment.
According to the invention, the successive segments can have different amplitudes and all of them do not cover the same region of the width of the output conveyor. The number of superimposed web layers is not the same in all of the regions of the width of the fleece. As the position of the folds can be chosen with relatively high accuracy, the profile of the fleece obtained distinctly and accurately complies with the theoretically desired profile.
The invention is particularly suitable for producing a fleece whose profile has at least one relatively sudden variation in thickness profile.
However, it is possible to soften the changes in thickness by slightly offsetting, with respect to one another, the folds of the same direction located at the limit between two zones having different thicknesses.
In order to produce an extra thickness between two thinner zones, it is possible to produce segments which cover only the extra thickness, and therefore limited by a fold along each of the longitudinal edges of the extra thickness, and other folds of greater amplitude covering the extra thickness and the two thinner adjacent zones. But it is also possible to produce an extra thickness between two thinner zones without forming any segment whose amplitude coincides with the width of the extra thickness. In order to do this, certain segments are produced starting from an edge of the extra thickness and covering the latter and the thinner zone adjacent to the other edge, and other segments starting from the said other edge and covering the extra thickness and the other thinner zone. This is convenient for making very narrow extra thicknesses, in the form of ribs.
According to another aspect of the invention, the crosslapper comprising:
an output conveyor;
a carriage which is transversely mobile above the output conveyor;
means of actuating the carriage to move in accordance with travels in each direction of the width of the output conveyor, separated by reversals of travelling direction;
means of supplying the carriage with a continuous web;
means carried by the carriage for feeding the web onto the output conveyor; and
means of profiling the fleece produced on the output conveyor, for providing the produced fleece with a stepped transverse profile
is characterized in that the profiling means comprise means of positioning at different locations in the width of the output conveyor at least certain of the successive reversals in the travelling direction of the carriage starting from a same travelling direction of the carriage, thereby to define over the width of the fleece at least two zones of different thickness which are separated by at least one shoulder.
According to a still further aspect of the invention, the device for producing a continuous textile product, comprising:
a crosslapper,
a consolidation
Bioul Jean-Pierre
Jean Robert
Jourde Bernard
Pene Michel
Asselin
Calvert John J.
Welch Gary L.
Young & Thompson
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