US2878541A - Slide fasteners - Google Patents

Description

Man-ch24, 1959 H. HANSEN SLIDE FASTENERS Filed Jan. 8, 1957 INVENTOR HARRY H A N s E N BY 01 m M M+ WM ATTORNEYS United States Patent SLIDE FASTENERS Harry Hansen, Valby-Copenhagen, Denmark Application January 8, 1957, Serial No. 633,009 Claims priority, application Denmark January 16, 1956 4 Claims. 01. 24-20543 This invent-ion relates to' a slide fastener of the type in which each row of coupling links consists of a continuous string shaped into serpentine-like configuration with open bends facing alternately one way and the other. The term string as used in this specification is intended to include any form of ribbon, band, thread, filament, strip or' s imilar ele'ment of any basic cross sectional configuration, commonly used or suitable for the production of slide fasteners of the type here in question, though it will generally be preferable to use a string of substantially rectangular or oblong cross section and to bend this perpendicularly to its principal plane so that in the finished serpentine-like structure the string will have its largest dimension directed perpendicularly to the longitudinal direction of the structure. The type of slide fasteners here considered is of particular interest where it is desired to make the rows of coupling links from flexible nonmetallic materials such as modern plastics, among which nylon is an example.

In a slide fastener of the type defined, every second bend of each string will be directed towards the middle of the slide fastener, or in other words towards the opposite row of coupling links for engagement therebetween. These bends will be referred to in the following as outward bends, while the loops therebetween having their closed ends directed away from the middle of the slide fastener will be referred to as the inward bends.

In slide fasteners of the type set forth, it has been proposed to construct the inward bends of the serpentinelike structure forming each row of coupling links with a slightly undercut configuration, i.e. in such a manner that the flank portions of these bends are slightly contracted to leave a slightly relatively widened head portion at the end of each bend. The purpose of this configuration is to secure the engagement between the serpentine-like structures in the closed position of the slide fastener, so that the bends will offer a certain resistance against being pulled out of engagement by forces acting in the plane of the slide fastener. Moreover, it has been proposed to use a string having an oblong and slightly curved profile for the serpentine-like structures in order to obtain some resistance against disengagement of the bends of the serpentine-like structures under the influence of forces acting in a direction perpendicular to the plane of the slide fastener. However, the known slide fasteners of this type have not been satisfactory. One reason for this is that the slightly undercut inward bends still have a relatively open configuration and are therefore very resilient so that they will yield even to relatively low opening forces acting in the plane of the slide fastener. Towards forces acting in a direction perpendicular to the plane of the slide fastener, particularly such forces as occur in the case of sharp bending of the slide fastener, the known slide fasteners of this type are even more vulnerable. One reason for this is that the slightly curved profile does not prevent mutual turning of the engaging bends about their common middle axis, particularly beice cause the relatively open inward bends may easily yield to facilitate such mutual turning, whereby the bends may be disengaged from one another. Special measures of a rather complicated and expensive nature therefore had to be made in order to prevent disengagement ofthe loops of the rows of coupling links under the influence of forces acting in a direction perpendicularly to the plane of the slide fastener.

It is an object of the invention to devise a slide fastener of the type set forth, in which a more reliable engagement than hitherto possible is obtained between the bends of the two serpentine-like structures forming the rows of coupling links of the slide fastener, without having to use any additional elements for securing such engagement. I

With this object in view, according to a principal feature of the invention, a slide fastener is provided inwhich each row of coupling links consists of a continuous string shaped into serpentine-like configuration with, open bends facing alternately one way and the other, the bends facing one Way having their. flankportions located closely together to form narrower neck portions behind "wider head portions, the strings of the two serpentine-like structures being constructed with profiles having surfaces for mutual engagement against both lateral displacement of the engaging bends relative to one another and relative turning of the loops about their common middle axis.

Other objects and features of the invention will be apparent from the following detailed description of some embodiments thereof, reference being made to the accompanying drawings, in which Fig. 1 shows on an enlarged scale the rows of coupling links of one form of a slide fastener according to the invention, as viewed perpendicularly to the plane of the slide fastener, and

Figs. 2-5 show sections along the line IIII of Figure 1 with four different shapes of the profiles of the strings forming the rows of coupling links.

In the slide fastener illustrated, each of the rows of coupling links consists of a string or band 1 and 2, respectively, extending the whole length of the slide fastener in the form of a serpentine, in which the inward bends 3, i.e. the bends having their closed ends facing away from the middle of the slide fastener, are relatively wide and spacious, while the outward bends 4, i.e. the bends having their closed ends facing the middle of the slide fastener, have their flanks 5 pressed completely together in an intermediate zone to leave relatively widened heads 6 at the closed ends of these bends. The fact that the flanks of the outward bends are directly supported against one another in the neck portions of the undercut outward bends, preferably even at a bias, has a considerably strengthening effect on the engagement between the bends.

In the embodiment illustrated in Figure 2, the string or band 1 is constructed with two longitudinal ridges 7 and 8 engaging with longitudinal recesses 9 and 10 respectively in the string or band 2. This engagement affords a firm support against unintentional disengagement of the bends under the influence of forces perpendicular to the plane of the slide fastener either by lateral displacement of the engaging bends relative to one another or by relative turning of the bends about their common middle axis.

In the embodiment illustrated in Figure 3, each of the strings or bands is constructed with two longitudinal ridges 7 and 8' of trapezoidal cross section, between which a longitudinal recess 9 of the same cross sectional shape is formed. The ridge 7' extends along one edge of the string, and at the other edge of the string there is formed a recess 10 equal to the recess 9' except that it is outwardly open along the edge of the string. As will be seen, vthe engaging surface of the whole profile is radially symmetric about a point in the longitudinal middle plane of the string. Owing to this construction the two strings will have exactly the same cross sectional shape and will still engage correctly with one another. This is a great advantage from the point of view of manufacture.

The embodiments of Figures 4 and are constructed according to the same principles as that of Figure 2, i.e. with profiles having their engaging surfaces radially symmetric about a point in the longitudinal middle plane of the'strings. The only difference between these embodiments and that of Figure 3 is that the ridges and recesses are constructed with rectangular cross sectional shape in Figure 4 in which the numerals are double primed and with rounded cross sectional shape in Figure 5 in which the numerals are triple primed.

Iclaim:

l. A slide fastener comprising a pair of engaging rows of coupling links in which each row of coupling links consists of a continuous filament having serpentine-like configuration with open bends facing alternately one way and the other, the bends facing one way having their inner flank portions in direct contact with each other to form narrower neck portions behind wider head portions, each filament having a profile which is the same over its entire length, said profiles having surfaces for mutual engagement against both lateral displacement of the engaging bends relative to one another and relative turning of the bends about their common middle axis.

2. A slide fastener as in claim 1 in which the said inner flank portions are biased in contact with each other.

3. A slide fastener as in claim 1 in which the profiles of the filaments of both rows of coupling links are mutually identical, the engaging surface'of each being radially symmetrical with respect to a point in the longitudinal middle plane of the filament.

4. A slide fastener as in claim 3 in which each filament is constructed with at least two longitudinal ridges alternating with longitudinal recesses of matching profile, a ridge being provided along one edge of the filament, and an outwardly open-recess being provided along the other edge of the filament.

References Cited in the file of this patent UNITED STATES PATENTS 2,048,544 Fritts July 21, 1936 2,514,750 Dobbs et a1 July 11, 1950 2,780,261 Svec et al. Feb. 5, 1957 FOREIGN PATENTS 936,801 Germany 22, 1955

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