Adhesive bonding and miscellaneous chemical manufacture – Surface bonding means and/or assembly means therefor – With stretching or tensioning means
Patent
1990-12-20
1993-08-17
Aftergut, Jeff H.
Adhesive bonding and miscellaneous chemical manufacture
Surface bonding means and/or assembly means therefor
With stretching or tensioning means
156440, 156494, 156164, 156229, 6043852, A41B 1300, A61F 1315
Patent
active
052365395
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a method of laying out pre-stretched elastic thread in curves on a continuously advancing web of material, preferably a layer of material which will form part of a diaper, said threads being intended to serve as leg elastic. The invention also relates to apparatus for carrying out the method.
BACKGROUND OF THE INVENTION
It is known in the manufacture of so-called disposable diapers to provide the diapers with elastic in order to elasticate the leg portions of the diapers and therewith hold said leg portions around the thighs of the wearer. An example of diapers of this kind is, described and illustrated in U.S. patent specification No. 3,860,003. These diapers have absorption pads or bodies of an hour-glass configuration, with which the narrower center part, intended to conform to the shape of the body, forms the crotch part of the diaper when the diaper is in use. However, elastic threads which are positioned rectilinearly and parallel with the longitudinal axis of the diaper tend to result in chafing of the skin of the wearer in the crotch region.
It is also known to apply elastic in a V-shaped pattern, where the elastic intersects the absorption pad in the vicinity of the crotch portion of the diaper. A diaper in which the elastic is positioned in this fashion will conform to the shape of the body more satisfactorily than the diaper of the aforesaid U.S patent, and also avoids irritating chafing of the crotch area in use.
It is also known to arrange the elastic threads in a network of threads, such as to provide a curved leg elastic in a manner similar to that found with tailor sewn leg apparel or garments. One method of providing such elastic is described in our Swedish Patent Specification 8406071-4.
For the purpose of laying out elastic threads in a curved path on a continuously advancing web of material, it is conceivable, for instance, to guide the thread applicator electrically, to and fro in the transverse direction of the web. Such manufacture, involving rapid transverse movements, is complicated, however, particularly in the case of high speed manufacture.
SUMMARY OF THE INVENTION
The present invention provides apparatus by means of which elastic threads can be placed in curved paths in a simple, efficient and speedy manner with the use of only a few movable parts.
The method for operating the inventive apparatus is characterized in that the threads are fed guided through or along curved grooves or slots provided in one more rotating rolls and are steered by the rolls as they are laid out onto said web, and that the threads are then bonded to the web with the aid of an adhesive
The apparatus for carrying out the method is characterized by at least one rotatable roll which is provided with a peripherally extending curved groove or slot, the axial amplitude of which controls the positioning of the threads on the material layer and achieves the desired curvature of the threads, and by a glue applicator for applying adhesive to the threads.
The roll may conveniently have the form of a tube provided with through passing slots for guiding the threads straight through the tube and laying the threads onto the material surface.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in more detail with reference to an embodiment thereof illustrated in the accompanying drawings, in which
FIG. 1 illustrates schematically and in perspective the positioning of elastic threads on a layer of material in a diaper manufacturing process;
FIG. 2 illustrates part of the apparatus shown in FIG. 1, said apparatus being a modified version of that in FIG. 1;
FIG. 3 illustrates a method of intermittently gluing the elastic threads;
FIG. 4 illustrates a diaper manufactured by means of the inventive apparatus;
FIG. 5 illustrates a deflecting roll which is a modification of the embodiments shown in FIGS. 1 and 3;
FIG. 6 illustrates a further embodiment of the invention;
FIG. 7 illustrates an embodiment in which the glue applicator is located w
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Andersen Verner E.
Rogberg John A.
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