MXPA01000729A - Apparatus for transporting a continuous web, and for manipulating the web - Google Patents

Abstract

The object of the invention is achieved by an apparatus (10) comprising a plurality of means for forming web loops (101), each means for forming web loops being positioned between adjacent web support plates (20), wherein each of the web support surfaces lies in an arc, the arcs lying around the circumference of a circular path, and wherein the web support surfaces and means for forming web loops (101) are rotatably mounted about the axis of the circular path. In a prefered embodiment of the invention, the means for forming web loops (101) is provided by rotatably driving the web support plates (20) around the circular path with a circumferential velocity, wherein the circumferential velocity is varied between a minimum circumferential velocity and a maximum circumferential velocity so that the distance between adjacent web support plates (20) varies between a minimum distance and a maximum distance. Preferably the circumferential velocity of the web support plates (20) varies according to a sinusoidal function, and wherein one cycle of the sinusoidal function corresponds to one complete rotation of the web support plate (20) around the circular path. The invention also relates to a process for transporting a continuous web around the apparatus whereby the distance between adjacent web support plates (20) is greater than the minimum distance, and wherein the web is transported around the circular path so that a web loop (101) is formed when the distance between adjacent web support plates (20) decreases towards the minimum distance.

Description

APPARATUS TO TRANSPORT A CONTINUOUS FRAME, AND TO MANIPULATE THE FRAME The present invention relates to an apparatus for transporting a continuous frame, and to manipulate the frame especially to form screen meshes. The apparatus is particularly useful in the manufacture of disposable absorbent articles, including diapers, adult incontinence products, sanitary napkins and the like. Manufacturing processes are often required to provide discrete strips of a material over a continuous web, such that the discrete webs of material are separated on one side along the length of the continuous web. The features manufactured in this way include elastic strips, an example of which is the elastic leg cuffs applied to the diapers. U.S. Patent No. 4 081, 301 issued March, 1978, discloses a process for applying a material, such as an elastic material, to a continuous web. The material is only glued along the length of the weft in discrete sections, such that when the weft is cut the elastic material remains extended only in the discrete section in which it has been stuck, and contracts from another part. . U.S. Patent No. 4,227,952, issued October 14, 1980, discloses a conveyor carrying separate weft support plates and wherein the continuous weft is enforced between the support plates to form weft meshes that It is known. Several features, such as the leg elastic, are then applied to the weft which is on the weft support plate, but not to the weft mesh. This training process requires less elastic material and provides material savings.

An apparatus of this type comprises a plurality of weft support plates, each weft support plate having an external weft support surface. However, the apparatus is mechanically complex and is not very suitable for high speed manufacturing machines. The object of the present invention is to provide a mechanically simpler and more reliable apparatus for applying the characteristics, including elastic characteristics, to a continuous web, in particular on a high-speed manufacturing machine. A further object of the invention is to provide a process for transporting and manipulating a frame using the apparatus of the invention.

BRIEF DESCRIPTION OF THE INVENTION The object of the invention is achieved by an apparatus comprising a plurality of means for forming turns in the frame, each means being placed to form turns in the frame between supporting plates of adjacent frames, wherein each of the supporting surfaces of the weft are located in an arc, the arcs lying around the circumference of a circular path, and wherein the supporting surfaces of the weft and the means for forming the turns in the weft are mounted rotatably about the axis of the weft. the circular path. In a preferred embodiment of the invention, the means for forming the turns in the frame are provided by rotatingly driving the frame support plates around the circular path with a circumferential speed, wherein the circumferential speed between a speed is varied. minimum circumferential and a maximum circumferential velocity such that the distance between adjacent support plates of the frame varies between a minimum distance and a maximum distance. Preferably, the circumferential speed of the weft support plates varies according to a sinusoidal function, and wherein a cycle of the sinusoidal function corresponds to a complete rotation of the weft support plate around the circular path. The invention also relates to a process for transporting a continuous web around the apparatus whereby the distance between adjacent support plates of the web is greater than the minimum distance, and where the web is transported around the circular path of the web. such that the loop is formed in the frame when the distance between the adjacent support plates of the frame decreases towards the minimum distance.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a diagrammatic representation of a cross section through the apparatus of the present invention. Figure 2 shows a more detailed cross section through the apparatus of the present invention, including linkages between the adjacent frame support plates. Figure 3 shows a perspective representation of the trajectory of a continuous web as it passes around the apparatus of the present invention in a first embodiment of the process of the invention. Figure 4 shows a perspective representation of the trajectory of a continuous frame as it passes around the apparatus of the present invention in a second embodiment of the process of the invention. Figure 5 shows a perspective representation of the trajectory of a continuous frame as it passes around the apparatus of the present invention in a third embodiment of the process of the invention. Figure 5a shows the profile of a curved elastic characteristic applied to the continuous web.

DETAILED DESCRIPTION OF THE INVENTION It will be readily apparent to those skilled in the art that while the following description of the present invention is in relation to a simple-use diaper structure having discrete elastic regions or strips, the present invention can be practiced with equal ease in almost any weft. In the following description a "continuous frame" is a web of material that is continuous in the machine direction. A preferred continuous web comprises a plurality of interconnected disposable absorbent articles for individual use, such as diapers. Typically, each diaper is comprised of an absorbent pad or absorbent core element, and elastomeric elements or patches. The absorbent pad elements and the elastomeric elements are located between a backsheet and a topsheet, or alternately, on top of a backsheet or a topsheet. The continuous webs of the backsheet material and the top sheet material are preferably kept under very light tension in the machine direction to prevent wrinkling and to facilitate registration with the diaper assembly and conversion operations until the entire diaper weave is separated into discrete diapers by cutting across the width of the weft. Figures 1 and 2 illustrate a cross-section through a preferred embodiment of the apparatus of the present invention. Illustrated is an apparatus having six weft support plates 20, each weft support plate comprising a weft support surface 22 facing outwards, and the weft support plates 20 are rotated in such a way that the surfaces of frame holder 22 tracing an essentially circular path. The apparatus will now be described with reference to one of the weft support plates as it moves around the circular path illustrated in Figure 1. A counterclockwise rotation is illustrated, but the invention can be equally well implemented with a clockwise rotation. As the weft support plate 20 passes through point A of the circular path (at the bottom of the circular path as illustrated in Figure 1), it has a maximum circumferential velocity Vmax. As the weft support plate 20 is rotated towards the top of the circular path it decelerates until it reaches a minimum circumferential speed Vm? N at point B of the circular path. As the weft support plate 20 continues around the circular path it descends until it returns to point A. The adjacent weft support plates are separated apart by a distance d. The adjacent frame support plates either side of point A in Figure 1 have a maximum distance d between them. As the frame support plates are rotated, one of the weft support plates has a faster circumferential speed than the adjacent weft support plate, and the faster weft support plate reaches the slower weft support plate, thereby reducing the distance between them . When the adjacent frame support plates lie either on the point side B in Figure 1 the distance between them is minimal. It is preferred that the circumferential velocity V of the weft support plates 20 vary according to a sinusoidal function, and wherein a cycle of the sinusoidal function corresponds to a complete rotation of the weft support plate 20 around the circular path . Consequently a continuous weft 100 placed against the weft support plates is transported around the apparatus and further the continuous weft 110 is manipulated in such a way that a loop is formed in the weft 101 adjacent to the adjacent weft support plates 20 as Adjacent frame support plates 20 move closely together. In a particularly preferred embodiment of the invention, the circumferential speed of the weft support plates is controlled by mechanical means. In Figure 1, the mechanical means comprises six extendable arms 30, i.e., an extendable arm 30 which drives each of the weft support plates 20. Each extendable arm 30 has a proximal end 32 and a distal end 34, being the proximal end 32 of each extendable arm 30 mounted on a second axis of rotation 35 and the distal end 34 of each extendable arm 30 being pivotally mounted on each frame support plate 20. The main shaft 25 and the second axis 35 they are parallel but not convergent in relation to each other, in such a way that the extendable arms 30 drive the weft support plates 20 around the circular path with the variable circumferential speed. Figure 2 shows a schematic representation similar to Figure 1, and additionally Figure 2 also illustrates preferred linkage means. The adjacent weft support plates 20 are pivotally connected to one another by the linkage elements 40. The linking means illustrated comprise a first link 41 and a second link 42. The first link 41 and the second link 42 are connected pivotally to each other near one end of the links, and the other end of each link being pivotally connected near the ends of the adjacent support plates of the frame 20. Figure 3 illustrates the path of a continuous frame 100 as it passes around the apparatus of the present invention in a first embodiment of the process of the invention. The weft is fed to a transfer roller 50 by a feeding means (not shown) and is transferred to the weft support surface of the apparatus. The apparatus itself is not shown in Figure 3 for clarity.

As the frame is drawn around the circular path by means of the frame support plates (not shown), the turns in the frame 101 are formed as described here above. Figure 3 also shows a pair of elastic strips 200 which are fed by a feeding means (not shown) towards the application points 104. At the application points 104 the elastic strips 200 are fixed to the continuous weft 100. The means Fixation is important in this invention and can be achieved by glue, thermal fusion, a self-adhesive material or any other means. Figure 3 also shows a cutting station 106 in which the elastic strips 200 are cut into discrete strips. The continuous web 100 is not necessarily cut in the cutting station 106, and it is actually preferred that the continuous web 100 not be cut in the apparatus of the present invention. The continuous screen 100 is not cut because the cutting station 106 is adjacent to a screen loop 101 as shown. Subsequently, the weft 100 accelerates around the apparatus, thereby releasing the turns in the weft 101, and the continuous weft with discrete lengths of elastic material adhered to it, discrete lengths of elastic material that is separated, the support surface is peeled off of the weft in a second transfer roller 52. Figure 4 illustrates the trajectory of a continuous weft 100 as it passes around the apparatus of the invention present in a second embodiment of the process of the invention. The weft is fed to a transfer roller 50 by means of a feeding means (not shown) and is transferred to the support surface of the weft of the apparatus. The apparatus itself is not shown in Figure 4 for clarity. As the web is pulled around the circular path by means of the web support plates (not shown), the turns are formed in the web 101 as described here above.

In Figure 4 elastic strips 200 are provided on the surface of an applicator roll 60. The elastic strips 200 are cut and deflected on the surface of the applicator roll 60 before the application point 104. Figure 5 illustrates the trajectory of a continuous screen 100 as it passes around the apparatus of the present invention in a third embodiment of the process of the invention. The weft is fed to a transfer roller 50 by a feeding means (not shown) and is transferred to the support surface of the weft of the apparatus. The apparatus itself is not shown in Figure 5 for clarity. As the web is dragged through the circular path by means of the frame support plates (not shown), the turns in the web 101 are formed as described here above. In Figure 5 a biasing means 70 is provided in order to apply a strip of elastic 200 in a curved profile. The deflection means 70 is adjacent to the application point 104 which moves in the transverse direction of the machine with a frequency corresponding to the cycle speed of the support plates of the frame 20. Figure 5a shows the profile of a Elastic curve characteristic applied to the continuous frame.

Claims (9)

1. An apparatus (10) for transporting a continuous weft (100), and for manipulating the weft (100), the apparatus comprising a plurality of weft support plates (20), each weft support plate (20) having a surface external support of the frame (22), the apparatus further comprising a means for forming turns in the frame (101) between the adjacent support plates of the frame (20), characterized in that each of the weft support surfaces ( 22) lie in an arc, each of the arcs lying around the circumference of a circular path, and wherein the supporting surfaces of the weft (22) and the means for forming the turns in the weft (101) are assembled rotationally about the main axis (25) of the circular path. An apparatus (10) according to claim 1, wherein the means for forming the turns in the frame (101) is provided by rotatingly driving the support plates of the frame (20) around the circular path with a circumferential velocity (V), wherein the circumferential velocity (V) is varied between a minimum circumferential velocity (Vm? n) and a maximum circumferential velocity (Vmax) such that distance (d) between the plates Adjacent support frames (20) varies between a minimum distance and a maximum distance. An apparatus (10) according to claim 2, wherein the circumferential velocity (V) of the support plates of the frame (20) varies according to the sinusoidal function, and wherein a cycle of the sinusoidal function corresponds to a complete rotation of the weft support plate (20) around the circular path. 4. An apparatus (10) according to claim 2, wherein each support plate of the frame (20) is driven around a circular path by an extendable arm (30), the proximal end (32) of each being extended arm (30) mounted on a second axis of rotation (35) and the distal end (34) of each extendable arm (30) being pivotally mounted on each frame support plate (20), and wherein the main shaft ( 25) and the second axis (35) are parallel but not convergent in relation to one another, such that the extendable arms (30) lead to the frame support plates (20) around the circular path with the circumferential speed variable (V). An apparatus (10) according to any one of claims 1 to 4, wherein the adjacent frame support plates (20) are pivotally connected to each other by means of linkage (40). 6. A process for transporting a continuous frame (100), and for manipulating the frame, wherein the frame is placed against the frame support plates (20) of the apparatus (10) of any of claims 1 to 5 in a position where the distance (d) between the adjacent plates of frame support (20) is greater than the minimum distance, and where the frame (100) is transported around the circular path in such a way that a loop is formed in the frame (101) when the distance (d) between the adjacent frame support plates (20) decreases towards the minimum distance. 7. A process according to claim 6 for applying a material (200) to the continuous web (100) wherein the material (200) is applied to the web (100) at an application point (104) which is adjacent to the circular path of the weft support plates (20), such that the material (200) is applied to that part of the weft that is located on one of the weft support plates (20) but the material (200) is not applied to the remaining part of the frame that is in the loop in the frame (101). A process according to claim 7, wherein the material is cut at a cutting station (106) such that the material (200) remains attached to the continuous web (100) only in discrete sections, each section corresponding to the part of the frame that is located adjacent to the frame support plate (20). 9. A process according to any of claims 7 or 8, wherein the material (100) is an elastic material, preferably an elastic material applied under tension at the point of application (104).