Garment fastener subassembly and method for making the same

Abstract

A fastener subassembly comprised of a fibrous support and a unitary fastener element secured thereto is provided by the successive introduction of solidified and fluid molding material into one of two dies opposingly clamped upon a non-apertured fibrous strip.

Description

FIELD OF THE INVENTION

This invention relates to garment fasteners and more particularly to fastener subassemblies comprising fibrous members having unitary fastener elements extending therethrough and to methods of manufacturing the same.

BACKGROUND OF THE INVENTION

In garment manufacture, style transitions to close-fitting apparel, e.g., so-called body suits for women, have occasioned greater demands for unobtrusive fasteners of increased strength. In the interests of efficiency in manufacture of this type of apparel the industry has generally adopted a fastener having cooperative subassemblies, each including a support member and a male and female fastener element joined thereto. The support members are sewn to garment portions intended to be releasably secured to one another.

Cognizant of the principal weakness in fasteners, i.e., the tendency for separation of the fastener element from its support, the art has undertaken various measures intended to extend the area of contact between the fastener element and its support and to improve the bonding force therebetween.

These prior art efforts fall generally into one of four classifications. In a first grouping, illustrated in U.S. Pat. Nos. 2,548,004; 3,176,365; 3,195,201; and 3,396,436; such efforts involve the provision of a non-unitary fastener element comprising two preformed interlocking parts disposed on opposite sides of a support member and joined together through the member. In a second grouping, shown in U.S. Pat. Nos. 3,019,152 and 3,169,292, they involve the provision of a preformed unitary plastic fastener element and a non-apertured support member and subsequent joinder of the fastener element to one side of the support member by rendering a surface portion of the fastener element fluid, e.g., by application of heat. In a third grouping, disclosed in U.S. Pat. No. 2,821,764, these efforts involve the provision of an apertured support member and the molding in situ thereon of a unitary fastener element, fluid plastic passing freely through the support member apertures to form portions of the molded fastener element on both sides of the member. In a fourth grouping, disclosed in commonly-assigned copending application Ser. No. 276,419 filed on July 31, 1972, now U.S. Pat. No. 3,800,368, the marginal edges of a non-apertured support member are folded onto the member forming a single-ply central expanse. So configured, the member is clamped between opposed dies and fluid molding material is supplied to one of the dies under pressure sufficient to rupture the member in its single-ply expanse and flow into the other die, thus also forming a unitary fastener element having portions on both sides of the member.

Fasteners of the first grouping have evident shortcomings as respects economy in manufacture since the fastener elements thereof are required to be preformed in multiple interfitting parts. In the case of fasteners of the second grouping, they are limited in strength since they do not have any fastener element structure extending completely through the support member. As to the third grouping, fastener manufacture is complicated by the need for providing an apertured strip member and carefully positioning the same relative to the fastener molding dies. Fasteners of the fourth grouping have evident advantage in respect of their provision of unitary fastener element structure securely joined to the support member and in respect of their simplified manufacturing method wherein a non-apertured support member is used.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide further improved garment fastener subassemblies and further simplified methods for manufacturing the same.

It is a more particular object of the invention to provide simplified methods for manufacturing fastener subassemblies of the fourth above-discussed grouping wherein support member rupture is more effectively accomplished than in presently known methods.

In brief summary thereof, methods of the invention comprise clamping a non-apertured fibrous support member between opposed dies each having a mold cavity and successively introducing, into one of the dies, solidified and fluid molding material under pressure sufficient to force the solidified molding material through the support member into the other die and to further fill both dies with the fluid molding material. The dies are separated following solidification of all molding material in the dies.

Other objects and features of the invention will be evident from the following detailed description of preferred embodiments thereof and from the drawings wherein like reference numerals identify like parts throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an injection head and shows a fibrous strip member in facing relation to separated dies of a mold configured to form a male fastener element and fastener subassembly in accordance with the invention.

FIG. 2 shows the injection head and dies of FIG. 1 in operative position for forming a male fastener element on the strip member of FIG. 1.

FIG. 3 illustrates the male fastener subassembly formed in the FIG. 2 operation.

FIG. 4 illustrates a preferred fibrous strip member arrangement.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, fibrous strip member 10, comprised of a fibrous material, woven or non-woven, e.g., cotton, and defining continuous and unapertured outer surfaces 10a and 10b, is disposed between a pair of separated dies 12 and 14. Die 12 defines a generally hemispherical mold cavity 16 having a material-receiving port 20 for the introduction of molding material into the cavity. As illustrated, die 12 also provides a seat for injection head 22. Die 14 defines a cavity 18 of configuration conforming with the desired male fastener element projection.

Injection head 22, which may comprise a conventional injection molding machine having an externally heated extruder cylinder of the screw-feed type, includes a material-issuing port 24, insertable in port 20 for communication therewith, and a conduit 26 for conducting fluid molding material to port 24. Head 22 also incorporates a duct 28 disposed in encircling relation to conduit 26 for conducting a coolant medium from coolant supply pipe 30 through head 22 to coolant return pipe 32 for selective head cooling prior to the making of each fastener element for purposes now discussed.

With die 12 separated from head 22 as shown in FIG. 1, extruder 34 is energized and fluid molding material, e.g., plastics, such as acetal resins sold under trademarks Celcon and Delrin, is accordingly supplied to conduit 26. Coolant is then supplied to pipe 30 to so cool the head in the vicinity of duct 28 as to solidify a preselected mass of molding material contained in a leading portion of conduit 26, e.g., as indicated as x in FIG. 1.

As shown in FIG. 2, dies 12 and 14 are arranged in clamping relation upon strip member 10, and cavities 16 and 18 engage, and extend respectively upwardly and downwardly of, surfaces 10a and 10b. With the dies and member so arranged, head 22 is seated in die 12. Extruder 34 is again energized, whereupon a pressurized stream of fluid material is applied in conduit 26 to the solidified mass of molding material thereby forcing or propelling the solidified mass from head 22 into cavity 16, onto and through strip member 10 and into cavity 18, as shown by broken line molding material slug 36 in FIG. 2. The pressurized stream of fluid material itself fills cavity 16, fills the passage formed by the slug in the strip member and further fills cavity 18. In the course of its passage through the strip member, the slug ruptures the strip member and individual fibers thereof are exposed and intermingle in random fashion with the fluid molding material. Since material 10 is fibrous and hence absorbent to the fluid plastic, additional amounts of fluid plastic saturate the expanses of member 10 adjacent the ruptured portion thereof and within the mold cavities.

With the fluid molding material so distributed in this manner in dies 12 and 14, injection head 22 is retracted into its FIG. 1 position and the die-contained molding material solidifies. Upon separation of cooled dies 12 and 14, the fastener subassembly illustrated in FIG. 3 is provided. As will be evident, this subassembly includes a unitary fastener element having male projection 38 conforming in configuration with mold cavity 18, generally hemispherical portion 40 extending upwardly of surface 10a and a further portion 42 intervening portion 40 and projection 38 and integral therewith. As occasioned by the rupturing activity above discussed, the fastener subassembly includes a random distribution of fibers embedded in fastener element portion 44 and projection 38 and integral with member 10. The solidified plastic is selected to have sufficient compressibility to permit the tip 38a of projection 38 adjacent undercut 38b to be readily released from die 14.

In repetitive manufacture, upon retraction of head 22, coolant is again supplied to duct 26 to form a solidified slug at portion x and the above-discussed molding operation is repeated.

A particularly preferred arrangement for the fibrous support member of fastener subassemblies according with the invention is shown in FIG. 4. In this arrangement, marginal portions 11a and 11b of fibrous support member 11 are folded onto the intermediate expanse 11c of the member, with edges 11d and 11e spaced slightly from one another. Member 11 is sewn to the garment such that marginal portions 11a and 11b are adjacent the garment surface and thus unfinished edges are not exposed.

Various combinations of molding materials and fibrous members are of course usable in practicing the invention and molding pressures, molding temperatures and solidifying temperatures are selected accordingly. The example below describes the particularly preferred practice of the invention.

EXAMPLE

A strip of cotton of breaking strength of approximately 200 to 300 pounds and of a thickness of 0.007 inch is placed between opposed dies as in FIG. 1 and the dies are closed thereon as in FIG. 2. Delrin molding material, heated to above its melting temperature, i.e., to about 350.degree.F., is extruder-fed into an injection head and 1/16 to 1/8 inch portion of the head adjacent the head issue port is cooled to a temperature between 100.degree. and 200.degree.F. by water cooling. The head issue port is seated in a receiving port in one of the dies. The extruder is again energized and feeds additional molten Delrin into the head at a pressure of two to five thousand psi. The head issue port delivers solidified and molten Delrin successively, and the solidified Delrin ruptures the cotton strip and enters the other die. The molten Delrin fills all volume interiorly of each die and the ruptured volume of the cotton strip. The dies are maintained at temperatures between 100.degree. and 200.degree.F., e.g., by water cooling. The molten Delrin solidifies and the dies are separated. Upon inspection of the male fastener element subassembly so formed, fibers of cotton in the strip rupture area are seen to extend from the strip into the molding material forming the male projection.

Various changes and modifications, evident to those skilled in the art, may be introduced without departing from the spirit of the invention. In this connection, the foregoing preferred embodiments of the invention are intended in an illustrative and not in a limiting sense.

Claims

What is claimed is:

1. A method for making a fastener subassembly comprised of a fibrous strip member and a unitary fastener element extending in part through said strip member and secured thereto, comprising the steps of: (a) arranging first and second dies, each defining a mold cavity, in opposed clamping relation to a non-apertured fibrous strip member; (b) supplying successively into one of said dies solidified and fluid molding material under pressure sufficient both to force said solidified material through said strip member to thereby rupture said strip member and define a passage in said strip member extending between the mold cavities and to force said fluid molding material into said passage and into each said mold cavity to fill said passage and each said mold cavity with said fluid molding material; (c) solidifying molding material in said passage and in each said cavity; and (d) separating said dies from said strip member.

2. The fastener subassembly provided by practicing the method claimed in claim 1.

3. A method for making a fastener subassembly comprised of a fibrous strip member and a unitary fastener element extending in part through said strip member and secured thereto, comprising the steps of: (a) arranging first and second dies, each defining a mold cavity, in opposed clamping relation to a non-apertured fibrous strip member; (b) solidifying a mass of fluid molding material; (c) applying a pressurized stream of fluid molding material to such solidified mass to force said mass into said first die mold cavity and onto said strip member to rupture said strip member and provide a passage in said strip member extending between the mold cavities; (d) further filling said passage and each said mold cavity with fluid molding material; (e) solidifying said molding material in said passage and each said cavity; and (f) separating said dies from said strip.

4. The fastener subassembly provided by practicing the method claimed in claim 3.

5. A method for making a fastener subassembly comprised of a fibrous strip member and a unitary fastener element extending in part through said strip member and secured thereto, comprising the steps of: (a) arranging first and second dies, each defining a mold cavity, in opposed clamping relation to a non-apertured fibrous strip member, said first die having a port for receiving molding material; (b) supplying fluid molding material to an injection head having a port for issuing molding material; (c) cooling said injection head to solidify molding material therein; (d) placing said material issuing port in communication with said material receiving port and applying a pressurized stream of fluid molding material to said injection head thereby propelling the solidified molding material therein into said first mold cavity and through said strip by rupture thereof and into said second mold cavity and further filling said mold cavities with fluid molding material; (e) solidifying said fluid molding material in said mold cavities; and (f) separating said dies from said strip.

6. The fastener subassembly provided by practicing the method claimed in claim 5.