Prong-attached garment fasteners devices with backing members
BACKGROUND OF THE INVENTION 
     This invention relates to garment fastening devices of the kind comprising a pronged fastener component adapted to be applied to one face of a portion of garment fabric material, and a backing member adapted to be applied to the opposite face of said portion of garment fabric material. The pronged fastener component has integral attachment prongs which penetrate through the thickness of the garment fabric material and are clenched on said backing member to clamp the latter to the material and thereby firmly secure and anchor the fastener component in place. 
     The invention is especially concerned with the backing member structure and an object of the invention is to provide for such garment fastening devices an improved simple form of effective backing member adapted to cover and conceal the clenched prongs of the pronged fastener component. The pronged fastener component may, for example, be a pronged hook component of a garment hook-and-eye fastener for the waistbands of trousers or skirts. 
     Various forms of backing member structures have hitherto been proposed which provide a covered internal space forming a clenching recess or recesses to receive the prongs of a pronged fastener component and which have integral interior cam surfaces to clench the prongs into said internal space. But the structural desgins of many of these prior proposals have often been bulky and such that the internal space forming the clenching recess or recesses has been relatively large. The control and guidance provided for the prongs has been insufficient reliably to avoid an unacceptable high proportion of defective clenchings of the prongs and to ensure a clenched configuration of maximum effectiveness, especially in mass production use. 
     It will be appreciated that provision for the pronged fastener component of a permanent secure reliable anchorage which will not become loose or unduly weaken the garment material under the stresses of working conditions is a major practical requirement. Factors important in relation to the above requirement include (1) the ability of the backing member, when provided with integral cam clenching surfaces, to control and influence the manner in which the prongs are clenched, even if the prongs are initially slightly misaligned or distorted, (2) the ability of the backing member to maintain and distribute an effective clamping pressure upon the garment material, and (3) the mechanical strength and rigidity of the backing member which is relevant to the possibility of accidental deformation or distortion before or after use. 
     Backing members of the general form mentioned, which include integral clenching cam surfaces and which cover and conceal the clenched prongs are particularly preferred when it is required to secure a pronged fastener component to a fully made-up garment so that the prongs are passed through a full thickness of garment material and the backing member is positioned on an exterior surface and may, in use, be exposed to view. Consequently, overall size and shape, bulk, and close fitting against the garment material, are further important characteristics of backing members of this general form which affect the commercial acceptability of the product. 
     Having regard to all the above factors the desirability has been recognized of providing improvements in the overall structural design of such backing members. 
     SUMMARY OF THE INVENTION 
     According to the present invention, a backing member, for a pronged fastener component of a garment fastener device of the kind referred to, is composed of sheet-metal and comprises a sheet-metal disc having a dished configuration with a convex exterior surface and a concave interior surface. Integral with said body portion, tongue elements are directed toward the center of the disc so as to lie within the recess formed by the concavity of the concave interior surface and in confronting relationship adjacent to or in juxtaposition with said concave interior surface. The tongue elements have apertures to register with the prongs of the pronged fastener component. Adjacent said apertures and towards the center of the disc are longitudinally extending groove or channel formations which, in co-operation with said concave interior surface, provide pockets adapted to receive and closely confine the bent-over outer end portions of the prongs of the fastener component. In securing said fastener component the prongs, pass through the respective adjacent apertures so as to be clenched and deflected into said pockets by forcible engagement at an oblique angle with the concave interior surface of the body portion. 
     The depth of the recess formed by the concavity of the concave interior surface adjacent the center of the disc may be between 2 and 3 times the thickness of the sheet-metal of the disc so that an exceptionally shallow structure is formed. The dished configuration is preferably formed by a substantially spherical curvature which extends over substantially the whole area of the disc thereby providing a structure which has an exceptionally high mechanical strength and which is well adapted to fit flush and neatly against the surface of the garment material. Peripheral free edge surface portions of the body portion bound and extend between the concave interior surface and the convex exterior surface and are preferably adapted to confront obliquely the surface of the garment material to which the backing member is applied. Consequently, when in use, said surface portions bear upon and embed into said garment material under the influence of the clamping pressure from the clenched attachment prongs of the fastener component, thereby enabling and facilitating the convex exterior surface to lie substantially flush with the surrounding adjacent surface of the garment material. 
     It will be appreciated that the convex exterior surface of the body portion can provide a decorative appearance and may, if desired, carry an ornamental pattern, whereby the backing member can be quite suitable and acceptable for applying to an exterior surface of garment material, such as a garment waistband for example, in a position where it is likely to be exposed to view. 
     The apertures may conveniently be disposed substantially mid-way between the center and periphery of the disc so that the backing member may cover a substantially larger area than the area of the seating surface of the pronged fastener component between the prongs. 
     In preferred embodiments, the tongue elements are provided by a pair of diametrically opposite radial lugs integrally connected at their root ends with the body portion at the periphery of the disc. The lugs are folded back so as to extend towards one another along a diameter within the recess formed by the concavity of the disc. Surfaces of said lugs are in substantially abutting engagement or contact with the concave interior surface. Also, the pockets are preferably each adapted to accommodate a single clenched attachment prong of the pronged fastener component disposed longitudinally therein. The groove or channel formations are provided by grooves or channels having a depth commensurate with the thickness of the sheet-metal and having opposite side walls forming lateral guide surfaces engageable with oppsoite side edges of the prongs during clenching so as to restrain twisting or skewing during entry of the prongs into said pockets. 
     Backing members in accordance with this invention can advantageously be used in conjunction with fastener components in the form of pronged hook members, especially pronged hook members of a kind comprising an elevated cantilever hook tongue integrally connected to a longitudinally offset base portion which carries the prongs and provides a seating surface which lies against the surface of the garment material. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     Other objects of this invention will appear in the following description and appended claims, reference being made to the accompanying drawings forming a part of the specification wherein like reference characters designate corresponding parts in the several views. 
     FIG. 1 is a rear elevational view of a first form of backing member, in accordance with the invention, for use with a pronged hook fastener component of a garment fastening device; 
     FIG. 2 is a front elevational view of the backing member of FIG. 1; 
     FIG. 3 is a section on line III-III of FIG. 1 showing the backing member in use for securing the pronged hook fastener component to garment material; 
     FIG. 4 is a sectional view similar to FIG. 3 but taken on line IV--IV of FIG. 1; 
     FIG. 5 is an elevational view of the hook fastener component attached to garment material by means of the backing member of FIG. 1; 
     FIG. 6 is a rear elevational view of a second form of backing member, in accordance with the invention, for use with a modified form of pronged hook fastener component; 
     FIG. 7 is a section on line VII-VII of FIG. 6; and 
     FIG. 8 is a section on line VIII-VIII of FIG. 6 showing the backing member in use for securing the modified pronged hook fastener component to garment material; and 
     FIG. 9 is a perspective view of the modified form of hook fastener component used with the backing member of FIG. 6. 
    
    
     DESCRIPTION OF SPECIFIC EMBODIMENTS 
     Referring first to FIGS. 1 to 5 of the drawings, the backing member 10 illustrated therein is designed for use with a hook fastener component 11 of a garment hook-and-eye fastening device suitable for connecting the ends of a waistband of a garment such as a pair of trousers or a skirt. The hook fastener component 11 has a single pair of parallel transversely spaced integral attachment prongs 12 extending perpendicularly from opposite peripheral edges of a base portion 13 which is integrally connected by a shallow step or cranking 14 to an elevated cantilever hook tongue 15 disposed in longitudinally offset relationship. 
     The backing member 10 is formed of sheet-metal, for example, sheet brass, and comprises a body portion 17 formed by a disc of the sheet-metal having a dished configuration with a convex exterior surface 18 and a concave interior surface 19. The curvature of the disc forming the body portion 17 is substantially spherical over substantially the whole area, and the concavity of the concave interior surface 19 forms a recess 20. The concave interior surface 19 and the convex exterior surface 18 are bounded by peripheral free edge surface portions 22 of the body portion 14 which extend between said interior and exterior surfaces 19 and 18. 
     The depth of the recess 20 adjacent the center of the disc of the body portion 14 is, as shown, between twice and three times the thickness of the sheet-metal. 
     The body portion 17 further has a pair of integral tongue elements 24 formed by a pair of diametrically opposite radial lugs integrally connected at their root ends with the body portion 17 at the periphery of the disc and folded back so as to be directed towards the center of the disc and to extend towards one another along a diameter within the recess 20. Surfaces of the tongue element lugs 24 confront and lie in substantially abutting engagement or contact with the concave interior surface 19. Thus, the tongue elements 24 are disposed at an angle with respect to each other. 
     Each tongue element 24 has an aperture 25 disposed substantially mid-way between the center and periphery of the disc body portion 17. Adjacent aperture 25 and towards the center of the disc body portion there is provided a longitudinally extending groove or channel formation 26, formed by a groove or channel of substantially rectangular cross-section, which, in co-operation with the concave interior surface 19, provides a pocket 27 adapted to receive and closely confine the bent-over outer end portion of a prong 12 of the hook fastener component passed through the adjacent aperture 25. It therefore follows from the disposition of the tongue elements 24 that the pockets 27 are formed at an angle with respect to each other. 
     In use, as indicated particularly in FIGS. 3 and 4, in attaching the hook fastener component 11 to a portion of garment material 28, the prongs 12 are forced through the garment material 28 from one side and then passed through the registering apertures 25 of the backing member 10 positioned at the opposite side. Under pressure exerted by a suitable press, the prongs 12 forcibly engage at an oblique angle with the concave interior surface 19 opposite to the apertures 25 and are deflected and bent-over towards the center of the disc body portion so as to enter the pockets 27 formed by the groove or channel formations 26 in co-operation with the confronting portion of the concave interior surface 19. 
     Thereby, the backing member 10 is clamped to the garment material 28 with the peripheral edge surfaces 22 of the disc body portion 17, which obliquely confront the opposed surface of the garment material 28, bearing upon and embedding into said material under the influence of the clamping pressure from the clenched attachement prongs 12. Clamping pressure is also transmitted to the garment material by confronting surface portions of the tongue elements 24 and the hook fastener component 11 is firmly secured or anchored in place with the attachment prongs 12 fully shielded and concealed from view. As is evident from the relationship of the confronting surface portions of tongue elements 24 and prongs 12, the clamping pressure is transmitted from prongs 12 through tongue elements 24 directly to the edge surface 22. Also, the convex exterior surface 18 lies substantially flush with the surrounding adjacent surface of the garment material 28, and a very effective and neat manner of fixing is achieved. As indicated in FIG. 2, the convex exterior surface 18 may be provided with a decorative ornamental pattern. 
     it will be seen that the groove or channel formations 26 of the tongue elements 24, 24, have a depth commensurate with the thickness of the sheet-metal of the backing member 10. This depth is substantially equal to the thickness of the sheet-metal forming the pronged fastener component so that the prongs 12 are forced to lie substantially flat in the pockets 27 and substantial curling of the prongs 12 within the pockets 27, which leads to potential weakness in the anchorage, is prevented. That is, the combination promotes flat surface contact between the prongs 12 and the interior surface 19. Also, the opposite side walls 29 of the groove or channel formations 26 form lateral guide surfaces engageable with opposite side edges of the prongs 12 during clenching so as to restrain twisting or skewing during entry of the prongs into said pockets. 
     When the hook fastener component 11 is secured to the garment material 28, the base portion 13 seats upon the surface of the material within an area opposite to the tongue elements 24 and lies fully within the area defined by the periphery of the backing member body portion 17. A relatively large area of the garment material is thereby involved in providing the anchorage for the hook fastener component, and, as indicated in the drawings, a segment s of the body portion 17 projects beyond the periphery of the base portion 13 so as to lie opposite to and in spaced relationship with the cantilever hook tongue 15 thereby to co-operate with said hook tongue in providing oppoosed relatively rigid jaws at opposite sides of the garment material to engage and confine the eye of a complementary staple or eye member. 
     The portion of garment material 28 illustrated may represent the end portion of the waistband of a pair of trousers or a skirt, for example, the side of the material to which the backing member 10 is applied being the exposed exterior surface of said waistband. 
     The second form of backing member illustrated in FIGS. 6 to 8 shows the manner in which the structure can be modified to suit a modified pronged hook component of the form shown in FIG. 9. The hook component 11a shown in FIG. 9 is generally similar to the first form of hook component 11 in that it has a cantilever hook tongue 15a integrally connected through a cranked step 14a to a longitudinally offset base portion 13a, but it differs in that the base portion 13a has two spaced apart pairs of side-by-side prongs 12a, 12a, in parallel relationship. 
     The modified form of backing member 10a is shown in FIGS. 6 to 8 and comprises a sheet-metal disc, constituting a body portion 17a, of shallow dished configuration, spherically curved over substantially its whole area. Again, the disc body portion 17a has a convex exterior surface 18a, a concave interior surface 19a defining by its concavity a recess 20a, and free peripheral edge surfaces 22a. And, again, a pair of tongued elements, 24a provided by a pair of diametrically opposed lugs integrally joined to the disc body portion 17a at the periphery. Lugs 24a are folded back to extend towards one another and lie within the recess 20a in closely adjacent substantially abutting confronting relationship with said concave interior surface 19a. Apertures 25a, located approximately mid-way between the periphery and center of the disc body portion, are formed in the tongue elements 24a adjacent groove or channel formations 26a extending longitudinally towards the center. In this modified form, the apertures 25a are each wide enough to receive a side-by-side pair of the prongs 12a and each groove or channel formation 26a comprises two separate side-by-side grooves or channels, of substantially rectangular cross-section, which in co-operation with the opposed concave interior surface 19a provide two side-by-side pockets 27a for the individual prongs 12a of each side-by-side pair which are restrained from twisting or skewing during entry into the pockets by opposite side walls 29a of the grooves or channels which form lateral guide surfaces. 
     Otherwise, the structure and manner of use of the backing member 10a in securing the pronged hook component 11a to garment material 28a is substantially the same as with the first embodiment.