METHOD AND APPARATUS FOR APPLYING ELASTIC BAND ONTO MOVING WEB

Abstract: A moving web (10) is folded at its predetermined length at its opposite side portions so that the opposite side portions are opposed to each other at a predetermined angle with its central portion. Then part of each of the opposite folded portions is outwardly folded. These foldings occur so that a first folding line (13) and a second folding line (14) being opposed to each other at each side of the web (10) include portions in non-parallel relationship. Elastic bands (12) are affixed onto the web (10) along the second opposite folded portions longitudinally and substantially in parallel to each other. When the web (10) is flattened from the folded condition, the paired elastic band (12) affixed onto the web (10) at its opposite sides each has a diagonal orientation symmetrically with respect to the direction in which the web (10) moves.

Description: The present invention relates a method and an apparatus to affix elastic band onto a continuous web (10) of article, the elastic band (12) on the article having at least partly an orientation being oblique with regard to a longitudinal axis of a web. The present invention is applicable, in production of disposable habiliments put on the crotch area of human body and provided with elastic band to assure fitness around the legs, for example, diaper, diaper cover and training pants for babies, to affix said elastic band onto such article at opposite sides of the crotch area in diagonal, curved or non-parallel disposition. To obtain desired fitness around the legs of user and thereby to minimize possible leakage of excretions, for example, in disposable diaper or pants, there have already been proposed the methods and the apparatuses for affixing the elastic band onto such article at opposite sides of the crotch area in diagonal or curved, i.e., non-parallel disposition. In such prior art, the inventive concepts have been often incorporated into the means to feed the elastic band to moving web as the primary component of continuous article and to affix this elastic band onto the web. However, to construct said means so that the elastic band can be affixed onto the web in non-parallel disposition, for example, diagonal or curved disposition, the mechanism of such means should be necessarily complicated and it is difficult for such complicated mechanism to be continuously operated at a high speed so that the elastic band may be affixed, through the entire lingth of the web, at predetermined positions in orderly and uniform manner. In view of such current situation, the elastic band has usually been affixed onto disposable diaper at opposite sides of the crotch area, regardless of the teachings of prior art. It will be readily appreciated that the diaper provided with the elastic band in such parallel disposition can not satisfactory fitness around the legs of user. This not only deteriorates appearance and feeling but also may cause leakage of excretions. GB-A-2 123 272 discloses an apparatus and a method for elasticizing disposable garments wherein a continuously moving elastic ribbon is moved into engagement with a continuously moving web of material while the elastic ribbon is being moved transversely of its length in an undulating pattern to produce an elasticized web. An oscillating means is provided which includes a rotatable roll around which the ribbon passes to impart oscillating movement to the ribbon just prior to its engagement with the web to thereby produce an undulating pattern of the ribbon on the web. US-PS 4 675 068 also related to an arrangement for bonding an elastic ribbon under tension to a plastics web along a curved path thereon with the aid of an adhesive. The ribbon is introduced into a given cured path on a cylindrical drum. Arranged in the given path are suction openings which communicate with a suction source and are effective in holding the ribbon firmly by suction along the whole of its length, therewith preventing the ribbon from sliding relative to the drum and the plastics web and from twisting or tilting on the drum despite the tension in the ribbon. Means are provided for breaking the connection between the suction openings and the suction source as the suction openings pass the end point of a given distance on the drum. All the prior art methods and apparatus do not work efficient enough under low cost conditions and/or do not provide an article having best fitness properties. The object of this invention is to overcome the problems as set forth above with relatively simple method and apparatus. ASPECT OF THE INVENTION The above-mentioned object is achieved by method and apparatus for affixing elastic band onto a continuous web (10) of article, the elastic band (12) on the article having at least partly an orientation being oblique with regard to a longitudinal axis of a web, respectively as follows: Method comprising steps of: i. first folding a predetermined length of said web at least corresponding to a single individual article at opposite side portions (16) thereof so that said opposite side portions (16) are standing upright and extend substantially parallel to each other, the folding lines (13) of said first folding defining at least partly slope areas (6) between each other, ii. second folding each of said opposite folded portions (16) outwardly at a second folding line (14) these foldings occurring so that a first folding line (13) and a second folding line (14) being opposed to each other at each side of said web include portions in non-parallel relationship in the region of the slope areas (6), iii. affixing the elastic band (12) onto said web along a portion defined between said second folding line (14) and the outermost edge at each side of said web, longitudinally and substantially in parallel to the elastic band on the other side of said web at least adjacent of the portions of the folding lines running in non-parallel relationship, and iv. flattening said web from said folded conditions so as to achieve a desired final position of said elastic band (12) so that said elastic band being affixed onto said web (10) at opposite sides thereof each has a diagonal orientation symmetrically with respect to the direction in which said web travels. Apparatus comprising: (7) An apparatus for affixing elastic band onto a continuous web (10) of article, the elastic band (12) on the article having at least partly an orientation being oblique with regard to longitudinal axis of a web, characterized in a support (1) having unevenly contoured peripheral segments in conformity with which said web (10) is folded and curved, each of said unevenly contoured peripheral segments including a rising central area (3a) defining a slope area (6a) gradually falling from at least one end of a segment middle portion to the other end in the same direction as said web (10) travels, stepped down edge areas (2a) formed along opposite sides of said rising central area (3a), and falling end area (4a) continuous with the lowest end of said slope area (6a) and having substantially same height as that of said stepped down edge areas; and means (7 - 9) to affix paired elastic band (12) substantially in parallel to each other onto said web (10) at portions thereof lying immediately on said opposite stepped down edge areas (2a) while said web is pressed against and folded in conformity with said unevenly contoured peripheral segment. Apparatus comprising: (4) An apparatus for affixing elastic band onto a continuous web (10) of article, the elastic band (12) on the article having at least partly an orientation being oblique with regard to a longitudinal axis of a web, characterized in a support (1) having unevenly contoured peripheral segments in conformity with which said web is folded and curved, each of said unevenly contoured peripheral segments including a grooved central (3) area defining a slope area (6) gradually rising from at least one end of a segment middle portion to the other end in the same direction as said web (10) travels, rising edge areas (2) formed along opposite sides of said grooved central area (3) and rising end area (4) continuous with the highest end of said slope (6) area and having substantially same height as that of said rising edge areas (2); and means (7 - 9) to affix paired elastic band substantially in parallel to each other onto said web (10) at portions thereof lying immediately on said opposite rising edge areas (2) while said web is pressed against and folded in conformity with said unevenly contoured peripheral segment. According to the method of this invention, as will be apparent from the aforegoing description, the opposite sides of the web are folded along the desired lengths thereof so as to form the first and second folding lines, said first folding lines and said second folding lines being partially in non-parallel relationship, and the paired elastic band is fed and affixed onto the web at the top surfaces of the opposite edges corresponding to the opposite second folded portions substantially in parallel to each other so that said paired elastic band may be disposed in non-parallel relationship, i.e., symmetrically diagonal when said web is flattened from said folded condition. Such unique feature advantageously eliminates the usual demand for the elastic band feeding/holding device, for example, having a complicated mechanism for deflection of said elastic band and enables the paired elastic band to be continuously fed and affixed in parallel relationship onto the web, in spite of the final result that said paired elastic band will be disposed on said web in non-parallel relationship. According to the apparatus of this invention, on the other hand, the unevenly contoured segments in conformity with which said web is folded and curved are formed along the supporting periphery of the support for this web. This unique feature advantageously simplifies a mechanism to dispose said paired elastic band on said web, eliminates possibility of troubles and malfunctions, and enables both the web and the elastic band to be worked at a high speed. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side view schematically showing a rotatable support as an apparatus of the invention used to execute a method of the invention; Fig. 2 is a fragmentary sectional view showing a part of said apparatus; Fig. 3 shows an unevenly contoured peripheral segment of said support in a cross-section taken along a line III - III in Fig. 2; Fig. 4 shows said unevenly contoured peripheral segment in a cross-section taken along a line IV -IV in Fig. 2; Fig. 5 is a fragmentary perspective view showing web as pressed against and thereby shaped in conformity with said unevenly contoured peripheral segment; Fig. 6 is a view similar to Fig. 5, showing said web after shaped and having pieces of elastic band affixed thereonto; Fig. 7 is a plan view showing said web after shaped and having pieces of elastic band affixed thereonto; Fig. 8 is a view similar to Fig. 7, showing said web after shaped and having pieces of elastic band affixed thereonto, but as having been flattened; Fig. 9 is a side view partially showing another embodiment of the rotatable support; Fig. 10 shows an unevenly contoured peripheral segment of said rotatable support in a cross-section taken along a line X - X in Fig. 9; Fig. 11 shows said unevenly contoured peripheral segment in a cross-section taken along a line XI - XI in Fig. 9; Fig. 12 is a sectional view illustrating an embodiment of the method according to the present invention wherein the unevenly contoured peripheral segements of the support, one of which is shown by Figs. 1 and 2 are utilized but the pieces of elastic band are affixed onto the web at positions different from those as in Fig. 2; Fig. 13 is a plan view showing the web after pressed against, thereby shaped in conformity with said unevenly contoured peripheral segments one of which is shown by Fig. 12, and then having the pieces of elastic band affixed thereonto; Fig. 14 is a view similar to Fig. 13, showing said web thus press-shaped and having the pieces of elastic band thereonto, but as having been flattened; and Fig. 15 and 16 are plan views illustrating another embodiment of the method according to the present invention wherein a configuration of said unevenly contoured peripheral segment and/or positions at which the pieces of elastic band are affixed onto the web may be varied to position the pieces of elastic band in a correspondingly varied pattern. PREFERRED EMBODIMENTS OF THE INVENTION The invention will be described more in detail, by way of example, in reference with the accompanying drawing. Referring to Figs. 1 through 4, there is shown an a pparatus for execution of a method according to the invention. The apparatus comprises a circular support 1 being rotatable around a central axis 0. The support 1 has at predetermined intervals along its periphery grooved central areas 3, rising edge areas 2 provided at opposite sides of the respective grooved central areas 3 and having their inner walls extend substantially in parallel with each other and substantially in perpendicularity to top surfaces of the associated grooved central areas, and relatively shallow grooved areas 4 extending between the adjacent grooved central areas 3 and presenting circular arcs each defined by a radius slightly shorter (or lower) than that of said rising edge areas. It should be understood here that such shallow grooved areas 4 may present their circular arcs defined by the same radius as that of said rising edge areas and these areas 4 will be referred to hereinafter as rising end areas 4. Each of said grooved central areas 3 has slope areas 6 gradually rising from a longitudinally middle position 5 of the segment towards opposite rising end areas 4. Closely around the support 1 having along its outer periphery unevenly contoured peripheral segments, there are provided three guide rollers 7a, 7b, 7c to guide a press-down belt 8 so that said belt 8 is pressed against the outer periphery of said support as said belt 8 travels in synchronization with said support. There are provided pressure rollers 9a, 9b in opposition to the top surface of the grooved central area 3 in order to urge the belt 8 against said top surface and these rollers are supported by suitable means with interposition of springs, respectively, so that said rollers may smoothly follow said grooved central area 3 and said rising end areas 4 regardless of a difference in heights of these areas. Closely around the support 1, there are additionally provided guide rollers 11a, 11b, and guide roller 11a being adapted to feed web 10 as primary constituting member of the continuous article and said guide roller 11b being adapted to take said web 10 out from the support. As shown in Figs. 1, 2 and 5, the web 10 is fed to the outer periphery of the support 1 which is rotating in a direction as indicated by an arrow and the pressure rollers 9a, 9b cause the belt 8 travelling in a direction as indicated by an arrow to press said web 10 against the grooved central area 3 and the associated rising end areas 4 so that said web 10 is folded and curved in conformity with these areas. There is provided above or laterally of the opposite rising edge areas 2, though not shown, a device operating synchronously with the support 1 to cut continuous elastic band (not shown) stretched and applied with suitable adhesive into pieces of predetermined length and to feed each of these pieces intermittently onto the web 10. Particular types of this device are not critical so far as the device functions in the manner as has been mentioned above and may be of prior art. This device enables the pieces of elastic band 12 to be affixed onto the web 10 substantially in parallel with each other along the tops of said opposite rising edge areas 2 which extend along opposite sides of the respective slope areas 6. As seen in Figs. 6 and 7, in a section of the web 10 that has been shaped and provided with the pieces of elastic band 12 affixed thereonto, opposite first folding lines 13 as well as opposite second folding lines 14 extend substantially in parallel to each other, respectively, and respective first folded portions 16 are substantially perpendicular to a central portion 18 and respective second folded portions 17 are substantially perpendicular to said first folded portions 16. However, when this section of the web 10 is flattened, the opposite second folding lines 14 are out of the parallel relationship and, accordingly, the opposite pieces of elastic band 12 form a non-parallel pattern as shown by Fig. 8. Such pattern of the elastic band pieces 12 will be repeated longitudinally of the web 10 and, once the continuous article has been completed, the web 10 will be cut along a middle line 15 between each pair of the longitudinally adjacent patterns of the elastic band pieces 12 into individual articles. As has previously been mentioned, the pieces of elastic band 12 are intermittently affixed onto the web 10 in this embodiment. However, it is also possible that the continuous elastic band 12 is intermittently applied with adhesive leaving portions which are not affixed onto the web 10, then said continuous elastic band 12 is affixed at said portions applied with adhesive onto the web 10 and cut at said portions having no adhesive so that these portions contract upon said cutting. Figs. 9 through 11 show another embodiment in which the circular rotatable support 1 has along its outer periphery unevenly contoured peripheral sigments each basically presenting a configuration being reverse to that in the support 1 shown by Figs. 1 through 4. More specifically, this support 1 of Figs. 9 through 11 has a rising central area 3a, stepped down edge areas 2a and grooved end areas 4a at positions corresponding to said grooved cantral area 3, said rising edge areas 2 and said rising end areas 4, respectively, of the previous embodiment. The rising central area 3a gradually falls from a segment middle area 5a towards the opposite grooved end areas 4a, forming respective slope areas 6a. The web 10 is pressed against the outer periphery of this support 1 so as to shape respective portions of the web 10 in conformity with the respective unevenly contoured peripheral segments of the support 1 and pieces of elastic band 12 are affixed onto the web 10 substantially in parallel to each other along the portions of the opposite grooved edge areas 2a that extend along opposite sides of the respective slope areas 6a. The pieces of elastice band 12 will form the pattern as shown by Fig. 8 when the web 10 is flattened. Figs. 12 through 14 show an embodiment in which the support 1 of Figs. 1 through 4 is utilized but the pieces of elastic band 12 and affixed onto the web 10 in a pattern different from that shown by Fig. 8. According to this embodiment, the pieces of elastic band 12 are affixed substantially in parallel relationship onto the web 10 along portions thereof lying on each rising end area 4 and the opposite rising edge areas 2 extending along opposite sides of the slope areas 6 extending to and from this rising end area 4. When the web 10 is flattened, the pieces of elastic band 12 form a pattern in which the bow-shaped pieces of elastic band 12 are disposed in non-parallel relationship. According to this embodiment, instead of disposing the pieces of elastic band 12 for each pair of individual articles on said portion of the web 10 as shown in Figs. 2, 5 and 6, the pieces of elastic band 12 for a single individual article are disposed on said portion of the web 10. Accordingly, circumferential lengths of the grooved central area 3 and each rising end area 4 in this support 1 should be shorter than those in the support 1 of Figs. 1 through 4. As will be readily understood from the foregoing description, configuration of the unevenly contoured peripheral segments and/or positions at which the elastic band pieces 12 are affixed onto the folded and curved web 10 may be selected to vary a non-parallel disposition of said elastic band pieces 12 on opposite sides of the flattened web 10, for example, as shown by Figs. 15 and 16. Although the circular rotatable support 1 having along its outer periphery the unevenly contoured segments in conformity with which the web 10 is folded and curved has been described above particularly with respect to two preferred embodiments, the object of the present invention can be also achieved by a circular arcshaped or a plate-like support which is preferably movable in the same direction as the web 10 travels in synchronization with said web 10, but may be stationary.

Claims: A method for affixing elastic band onto a continuous web (10) of article, the elastic band (12) on the article having at least partly an orientation being oblique with regard to a longitudinal axis of a web, characterized by the following steps: i. first folding a predetermined length of said web at least corresponding to a single individual article at opposite side portions (16) thereof so that said opposite side portions (16) are standing upright and extend substantially parallel to each other, the folding lines (13) of said first folding defining at least partly slope areas (6) between each other, ii. second folding each of said opposite folded portions (16) outwardly at a second folding line (14) these foldings occurring so that a first folding line (13) and a second folding line (14) being opposed to each other at each side of said web include portions in non-parallel relationship in the region of the slope areas (6), iii. affixing the elastic band (12) onto said web along a portion defined between said second folding line (14) and the outermost edge at each side of said web, longitudinally and substantially in parallel to the elastic band on the other side of said web at least adjacent of the portions of the folding lines running in non-parallel relationship, and iv. flattening said web from said folded conditions so as to achieve a desired final position of said elastic band (12) so that said elastic band being affixed onto said web (10) at opposite sides thereof each has a diagonal orientation symmetrically with respect to the direction in which said web travels. A method as recited in Claim 1, wherein the portions (16) folded along said respective first folding lines (13) are substantially perpendicular to a central portion (18) defined between said respective first folding lines. A method as recited in Claim 1, wherein the portions folded along said respective second (14) folding lines are substantially perpendicular to said portions (16) folded substantially perpendicularity to said central portion (18). An apparatus for affixing elastic band onto a continuous web (10) of article, the elastic band (12) on the article having at least partly an orientation being oblique with regard to a longitudinal axis of a web, characterized in a support (1) having unevenly contoured peripheral segments in conformity with which said web is folded and curved, each of said unevenly contoured peripheral segments including a grooved central (3) area defining a slope area (6) gradually rising from at least one end of a segment middle portion to the other end in the same direction as said web (10) travels, rising edge areas (2) formed along opposite sides of said grooved central area (3) and rising end area (4) continuous with the highest end of said slope (6) area and having substantially same height as that of said rising edge areas (2); and means (7 - 9) to affix paired elastic band substantially in parallel to each other onto said web (10) at portions thereof lying immediately on said opposite rising edge areas (2) while said web is pressed against and folded in conformity with said unevenly contoured peripheral segment. An apparatus as recited in Claim (4), wherein said opposite rising edge (2) areas have respective inner walls substantially in parallel to each other and substantially perpendicular to the top surface of said grooved central area (3) An apparatus as recited in Claim (4 or 5), wherein said support (1) comprises a circular rotatable member adapted to be rotated synchronously with said web in the same direction as said web travels and said rotatable member has along its outer periphery a plurality of said unevenly contoured peripheral segments. An apparatus for affixing elastic band onto a continuous web (10) of article, the elastic band (12) on the article having at least partly an orientation being oblique with regard to a longitudinal axis of a web, characterized in a support (1) having unevenly contoured peripheral segments in conformity with which said web (10) is folded and curved, each of said unevenly contoured peripheral segments including a rising central area (3a) defining a slope area (6a) gradually falling from at least one end of a segment middle portion to the other end in the same direction as said web (10) travels, stepped down edge areas (2a) formed along opposite sides of said rising central area (3a), and falling end area (4a) continuous with the lowest end of said slope area (6a) and having substantially same height as that of said stepped down edge areas; and means (7 - 9) to affix paired elastic band (12) substantially in parallel to each other onto said web (10) at portions thereof lying immediately on said opposite stepped down edge areas (2a) while said web is pressed against and folded in conformity with said unevenly contoured peripheral segment. An apparatus as recited in Claim 7, wherein opposite outer walls of said rising central area (3a) are substantially in parallel to each other and substantially perpendicular to the top surface (5a) of said rising central area (3a). An apparatus as recited in Claim (7 or 8), wherein said support comprises a circular rotatable member (1) adapted to be rotated synchronously with said web (10) in the same direction as said web travels and said rotatable member (1) has along its outer periphery a plurality of said unevenly contoured peripheral segments.

Inventors: KOBAYASHI, SHIGETOYO, NOMURA, HIRONORI, SHIMAKAWA, TAIJI, SHINOHARA, JUNJI, YAMAMOTO, HIROKI
Applicants: UNI-CHARM CORPORATION
Application year: 1988
Main classification: A61F13
IPC codes: A61F13, B65H20, C09J5