Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2001-05-15
2003-07-22
Ball, Michael W. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S204000, C156S226000, C156S227000, C604S385201, C604S385300, C604S385210, C604S390000
Reexamination Certificate
active
06596113
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention pertains to processes and apparatus for handling material webs, and more particularly to processes and apparatus for making prefastened garments.
Garments such as disposable absorbent garments have numerous applications including diapers, training pants, feminine care products, and adult incontinence products. The typical disposable absorbent garment is formed as a composite structure including an absorbent assembly disposed between a liquid permeable bodyside liner and a liquid impermeable outer cover. These components can be combined with other materials and features such as elastic materials and containment structures to form a product that is specifically suited to its intended purposes.
Manufacturing techniques for making conventional garments are in some respects inadequate for making new product forms, such as prefastened and refastenable garments. Hence, what is lacking and needed in the art are new processes and apparatus for handling material webs, and in particular in relation to making prefastened garments such as disposable absorbent pants.
SUMMARY OF THE INVENTION
In response to the above-referenced unfulfilled need in the art, new processes and apparatus for handling material webs and making prefastened garments have been discovered. One aspect of the present invention pertains to the use of an air knife for material handling. The air knife can be used to position a material for bonding, fastening, or other purposes. The material can comprise any relatively flexible material, whether permeable or impermeable to fluids, such as woven materials, nonwoven materials, films, or the like. The air knife can be used to control and/or guide the position of materials comprising mechanical fastening components which tend to engage other materials which they contact.
Hence, in one embodiment, a method of folding a material includes transporting a material in a machine direction and transporting a panel of the material in operative proximity to an air knife. The air knife comprises a nozzle and a curved Coanda surface. Air is expelled from the nozzle such that the panel is folded over the curved Coanda surface as the material is transported in the machine direction.
Operation of the air knife creates an air sheet formed of the expelled air jet and entrained ambient air. The Coanda surface creates a pressure differential across the two sides of the air sheet, forcing the air sheet to “attach” to and follow the Coanda surface. The panel, when transported in operative proximity to the air knife, is drawn to and carried on the air sheet. For purposes of the present application, a material or panel is considered in “operative proximity” to an air knife when the material or panel is spaced sufficiently close to the air knife to have its path of travel impacted by operation of the air knife.
In the present methods, the Coanda surface is curved with respect to the nozzle flow direction, and the panel is carried or folded over the curved surface. For purposes of the present invention, a panel or portion of a material being “folded over a curved Coanda surface” means that the panel is drawn toward the curved surface and wraps over and around the curved surface, supported by the cushion of air flowing over the curved surface. In other words, the panel is inwardly folded about an axis, where the curved Coanda surface is disposed between the axis and the panel. As the material and panel are transported in the machine direction, the panel can be folded from a generally planar position prior to the air knife to a fully folded position further downstream, such that the angle or degree of the fold increases with movement in the machine direction. In particular embodiments, the panel can be folded through an angle of about 45 or greater, and more particularly about 90 degrees or greater. As discussed in greater detail below, the panel can comprise a refastenable fastening component, for example in relation to embodiments concerning refastenable garments.
Another aspect of the invention concerns a method of forming a prefastened pant. One embodiment of such method comprises transporting a stream of discrete, partially assembled and folded pants in a machine direction. Each pant comprises a first waist region with opposed first side panels and a second waist region with opposed second side panels. The method further comprises transporting the first side panels in operative proximity to air knives, which comprise nozzles and curved Coanda surfaces. Air is expelled from the nozzles such that the first side panels are folded over the curved Coanda surfaces. The second side panels are folded into position transversely outward from the first side panels, and the respective first and second side panels are permanently or refastenably bonded together.
Another embodiment of the method of forming a prefastened pant comprises transporting a stream of discrete, partially assembled and folded pants in a machine direction, and transporting the first side panels in operative proximity to air knives. In this embodiment, each pant comprises a first waist region with opposed first side panels including first fastening components, and a second waist region with opposed second side panels including second fastening components. The fastening components are capable of refastenably engaging one another. Each air knife comprises a nozzle and a Coanda surface. Each Coanda surface defines a curved portion and a generally planar portion, where the curved portions are disposed between the nozzles and the generally planar portions. Air is expelled from the nozzles such that the first side panels are folded over the curved Coanda surfaces with the first fastening components disposed on the generally planar portions. The second side panels are moved into overlapping orientation with the first side panels, with the second fastening components positioned transversely outward from the first fastening components. The first and second fastening components are refastenably engaged.
To facilitate high speed formation of the refastenable pants, the air knives can be mounted in a cantilevered configuration, so that the refastenably engaged side panels are transported past the downstream ends of the air knives. In particular embodiments, air is expelled from the nozzles in a direction generally perpendicular to the machine direction. Various techniques can be used to move the second side panels into overlapping orientation with the first side panels. For example, a reciprocating panel folding head can intersect the path of travel of the second side panels. Air knives can also be used to position the second side panels.
A further aspect of the invention concerns an exhausted air knife. In one embodiment, the air knife comprises a plenum defining an internal chamber, a nozzle operatively connected to the internal chamber and defining a nozzle flow direction, and a Coanda surface adjacent and extending beyond the nozzle. The Coanda surface can be curved in cross section relative to the nozzle flow direction and can define a curvature of about 90 degrees or greater from the nozzle to a terminal edge. In this embodiment, the Coanda surface comprises first and second curved portions and first and second generally planar portions, where the first curved portion is disposed between the nozzle and the first generally planar portion and the second curved portion is disposed between the first and second generally planar portions. A flange is positioned in close proximity to the Coanda surface opposite the second generally planar portion and defines therebetween an exhaust passage.
Another embodiment of the exhausted air knife comprises a plenum defining an internal chamber, and a cap attached to the plenum. The cap comprises a first flange, a second flange and an intermediate member connecting the first and second flanges. The first flange is positioned in close proximity to the plenum and defines therebetween a nozzle that is in fluid communication with the internal chamber. The second flange
Csida Jason Gene
Hietpas Lloyd Carl
Lohoff Michael Lee
Tomsovic Charles Robert
Vogt Brian Robert
Ball Michael W.
Gage Thomas M.
Kimberly--Clark Worldwide, Inc.
Rossi Jessica
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