Buckles – buttons – clasps – etc. – Including readily dissociable fastener having numerous,... – Having mounting surface and filaments constructed from...
Reexamination Certificate
2000-12-15
2002-03-19
Sakran, Victor N. (Department: 3626)
Buckles, buttons, clasps, etc.
Including readily dissociable fastener having numerous,...
Having mounting surface and filaments constructed from...
C024S304000, C024S442000, C024S446000
Reexamination Certificate
active
06357088
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to improved hook members for hook-and-loop fastening and methods of manufacturing hook members.
In general, hook-and-loop fasteners comprise two mating components: a hook member that has upstanding, hook-type fastener elements, and a loop member that has a surface that provides fibers or fiber loops with which the hook elements become engaged.
As used here, a “hook member” means a member having fastener elements whose hooks extend substantially in a given plane. When of molded form, the stems of these elements are significantly broader in the direction of their plane of extent than in the thickness direction at a right angle thereto.
Hook fasteners are often preferred over other types of fasteners, for instance, those having mushroom-like form, because hook fasteners can provide more secure engagement with the loops, offer advantages in manufacturing, etc.
Loop members for hook-and-loop fastening have been comprised of knitted, woven, and non-woven textiles. A common example of a non-woven textile is known by the term “spun bonded”. It is made by spinning fine filaments of plastic resin, e.g., polypropylene, and distributing them in superposed layers. The fibers are bonded to each other in random orientations, with a fine, low-lying, nappy layer of looped and arched fibers exposed at the surface of the fabric.
Because non-woven fabrics are inexpensive, they are desired for use as the loop part of fasteners for low cost items, particularly disposable products such as diapers, surgical gowns, and sanitary napkins. It is desirable to provide fastener members useful with very low cost, low loft non-wovens and other low loft fabrics.
SUMMARY OF THE INVENTION
One aspect of the invention relates to a fastener member useful for separable engagement with surface fibers of a low-loft, non-woven fabric or the like. The fastener includes a base and multiple rows of molded hook-form fastener elements extending from the base and exposed for engagement with the fabric. Each of the hook form fastener elements comprises a stem portion joined at one end to the base and at least one fiber-engaging hook-form portion joined at the opposite end of the stem portion and having a free end. The hook-form fastener elements lying substantially only in planes aligned with respective rows. At least some of the fastener elements include a fiber-engaging plate portion at the outermost portion of the hook-form portion, which plate portion lies generally parallel to the base. The plate portion provides an overhanging portion in the direction perpendicular to its row that can engage the surface fibers of the fabric.
Certain implementations of this aspect of the invention include one or more of the following features. The fastener member, in certain implementations, provides: a plate portion which has a thickness, in the direction normal to the base, that is less than the height, in the direction normal to the base, of the free end of the hook portion; fastener elements formed of thermoplastic resin, the stem portions of the elements being molded integrally with the base, and the plate portion comprising a post-formed structure formed from the resin of the uppermost portion of the molded fastener element; that substantially all the hook-form portions of the fastener elements in a first row extend in one direction along the row and substantially all the hook-form portions of the fastener elements in a neighboring second row extend in the opposite direction; that substantially all of the fastener elements include plate portions; that substantially all of the fastener elements in the first row contain a plate portion while substantially all of the elements in the neighboring second row do not; a stem portion which has substantially flat relatively broad sides, a cross-section of each stem portion, taken parallel to the base at the mid-height region of the stem, having a width in the direction of the row and a thickness in the direction perpendicular to the row, the width being about twice the thickness or more; a stem in which the width of the stem tapers from the base to the hook-form portion; a central axis of the stem is inclined, in the direction of the respective row, at a substantially acute angle relative to the base.
Another aspect of the invention relates to a fastener member useful for separable engagement with surface fibers of a low-loft, non-woven fabric or the like. The fastener comprises a base and multiple rows of molded fastener elements extending from the base. Each fastener element comprises a stem portion joined at one end to the base, the stem being inclined, at a substantially acute angle relative to the base in the direction of the respective row of the element, and lying substantially only in planes aligned with its respective row relative to the base, and a fiber-engaging plate portion disposed at the opposite, outermost end of the stem portion, the plate portion extending transversely to the direction of the respective row to form an overhang portion that can engage the surface fibers of the fabric.
Certain implementations of this aspect of the invention include one or more of the following features. The fastener member, in certain implementations, provides a cross-section of each stem portion, taken parallel to the base, has a width in the direction of the row and a thickness in the direction perpendicular to the row, the width being substantially greater than the thickness; that substantially all of the fastener elements include plate portions.
In accord with another implementation of the invention, a closure is provided comprising a fastener member as described above and a non-woven fabric engaged therewith, the base of the fastener and the non-woven fabric being under tension in opposite directions such that the fastener elements are subjected to and resist shear forces caused by the tension loading, the tension acting in the direction of the thickness of the stem portion.
Another aspect of the invention relates to a method for making fastener members comprising extruding molten resin and applying the resin to a molding roller having forming cavities around its perimeter. Pressure is applied to the resin to cause the resin to fill the cavities, thereby forming a fastener member preform, the fastener member preform comprising a base and a multiplicity of discrete fastener element preforms integrally molded with and extending from the base at a substantially acute angle, the fastener element preforms aligned in at least one row comprising stem portions with outermost ends lying over the base substantially only in planes aligned with its row. Fastener member preforms are stripped from the molding roller. The outermost portions of at least some of the fastener element preforms are flattened, thereby forming generally plate-shaped portions disposed at the outermost ends and generally parallel to the base and perpendicular to the row.
Certain implementations of this aspect of the invention include one or more of the following features. The method, in certain implementations, provides: the flattening comprises heating the outermost ends of at least some of the fastener element preforms to a temperature that is near the melt temperature of the resin and applying pressure to the outermost ends; the heating and the applying pressure are performed in a single step; the single step comprises passing the fastener member preforms by a heated roller and pressing at least some of the fastener element preforms against the heated roller; the fastener member preforms are formed and the outermost ends of at least some of the preforms are flattened as part of a single, continuous process; the outermost ends of at least some of the fastener element preforms are flattened in a post-processing operation; prior to the flattening, differences in the heights of the fastener element preforms are corrected to ensure generally uniform height; the correcting comprises pressing a knock-down roller against the outermost ends of the fastener element preforms; that subs
Condon Mark J.
Leak A. Todd
Provost George A.
Roslansky Apiromraj S.
Serbiak Paul J.
Sakran Victor N.
Velcro Industries B.V.
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