Strip Fasteners

Abstract

In a slide fastener wherein a barbed rib of a male strip is arranged to interlock with a barbed jaw of a female strip, the jaw of the female strip is closed by the slider by means of a locking strut which is hinged to the female strip over one of the barbed fingers which defines the jaw, the locking strut being firmly engageable by a recess in the one barbed finger.

Description

This invention concerns strip fasteners often referred to merely as clasp fasteners. A typical example of such fasteners described and claimed in British Pat. No. 914,203.

One object of this invention is to provide an improved fastener which generally more satisfactorily meets present day requirements and which, in particular, is formed by interlockable strips which, when desired, easily interlock with one another or disengage from one another but which cannot easily become disengaged either by accident or as a result of the existence of substantial separating forces. Another object of the invention is to provide a fastener which may be used as a closure for receptacles in applications where it is essential that air, moisture and dust transmission rates must be minimal.

According to one aspect of this invention there is provided a strip fastener comprising a female strip and male strip adapted to be interlocked with one another, the female strip being provided with a longitudinal groove bounded, and defined by, a pair of spaced-apart barbed fingers which, with the groove, form a jaw which is dimensioned to receive a barbed rib extending longitudinally of the male strip, at least one of the fingers being movable from a position in which the rib of the male element may be easily introduced into, or withdrawn from, the said jaw into a position where the fingers would interlock with the barbed rib of a male element introduced therein so as to prevent withdrawal thereof, and means being provided to lock the or each said movable finger in the position in which the jaw would retain the male strip in position.

According to one feature of this invention, the strips may be extruded, or otherwise formed, from a resilient material such as for example a thermoplastics material such as plasticized polyvinylchloride, a polyolefine or ethylene vinyl acetate, or alternatively a natural or synthetic rubber.

Expediently each strip may carry a flange whereby it may be secured to structure which is to be interconnected by the fastener.

The or each movable finger may be dimensioned so that it or they may readily flex with respect to the remainder of the female strip except when interlocked with a strut formed integrally with such strip.

According to one feature of the invention one finger only may readily flex and the interlocking strut is formed by a length of material integral with the female strip and which is adapted to snap into a recess extending along such finger, said interlocking strut and said recess being shaped so that they interlock firmly and cannot be disengaged without deformation either of the strut or of the finger.

Conveniently the strips constituting a fastener may carry means whereby a slider may be secured across the same and be guided for longitudinal movement therealong, movement of the slider in one direction acting to separate the strips while movement of the slider in the opposite direction serving to draw together and interlock the two strips.

Preferably the slider may be provided with a pair of divergent channels in which the strips respectively ride, a lip being provided in the channel in which the female strip rides to effect movement of the strut with respect to the movable finger, the channels being divergent to draw together, or move apart, strips on movement of the slider along the fastener strips.

According to another feature of the invention there is provided, for a strip fastener in accordance with this invention, a female strip provided with a longitudinal groove bounded, and defined by, a pair of spaced-apart barbed fingers and in which one of such fingers is movable to open or close the jaw except when locked in a jaw closing position by said locking means.

Likewise in accordance with yet another feature of the invention there is provided, for a fastener in accordance with this invention, a male strip having a barbed rib extending therealong.

According to a still further feature of the invention there is provided a container having a opening bounded by, and closable by, a fastener according to this invention.

In order that the invention may be more readily understood one embodiment of fastener in accordance with this invention will now be described by way of example, and with reference to, the accompanying drawings in which:

FIG. 1 is a perspective view of a part of a fastener according to this invention, the strips thereof being shown to be partially interconnected, a slider for conveniently separating or interconnecting such strips also being shown;

FIG. 2 is a perspective view of a receptacle having an opening bounded by, and closable by, a fastener of the kind shown in FIG. 1;

FIG. 3a is enlarged perspective view of a male strip forming one part o the fastener whereas

FIG. 3b is similar view but of a female strip forming the other part of the fastener;

FIG. 4 is an exploded perspective view of the slider shown on the fastener in FIG. 1;

FIG. 5 is an underneath plan view of the slider of FIG. 4;

FIGS. 6a to 6d are a series of cross-sectional views respectively taken on the lines a -a; b-b; c-c; and d -d of FIG. 5; and

FIGS. 7a to 7e are a series of transverse cross-sectional views taken through the strips of the fastener shown in FIG. 1, these FIGS. showing the change in cross-sectional shape of the female strip which occurs as the slider causes the strips progressively to become drawn together and interlocked.

In this embodiment the fastener comprises a female strip and a male strip. Both strips are extruded from a length of resilient plastics material such as, for example, plasticized polyvinylchloride.

The female strip designated 1 is provided with a longitudinally extending groove 2, bounded and being defined by a pair of spaced apart fingers 3,4 each of which are barbed at 5. Such fingers are effectively formed by longitudinally extending ribs on the female strip. The fingers 3 and 4, in conjunction with the groove 2, form a jaw.

The finger 4 is provided with a narrowed portion or neck 6 which makes the finger 4 sufficiently flexible at this position to enable the finger 4 to be moved with respect to the finger 3 from a jaw open position to a jaw closed position and vice versa. finger

The female strip 1 is also provided with a strut 7 which has a narrowed portion 8 towards its root which enables the strut 7 to be moved angularly from a position where it lies spaced from the finger 4 (and permits the latter to move to a jaw open position) to a finger locking position where the strut 7 lies within a rebate 9 in the finger 4 and retains such finger 4 in a jaw closing position. The rebate 9 lies on that surface of the finger 4 which is opposite the surface there of which defines the jaw and such rebate extends towards the free end of the finger 4 from a position adjacent the root thereof, that is from a position adjacent the narrowed portion or neck 6.

Extending from the female strip 1, at a position opposite said jaw, is a flat longitudinally extending flange 10 provided to enable the strip to be secured to a piece of material such as, for example, a piece of material forming a receptacle. The strip flange 10 may be secured to the material in any desired manner such as, for example, by means of an adhesive or by welding.

A groove 11 is provided at the root of the flange to provide a guide for a slider to be referred to hereinafter.

The male strip of the fastener comprises a main body 12 which is provided with a longitudinally extending rib 13 which is barbed at its free end at 14. The main body 12 carries an extension 15 which has a domed head 16, this extension 15 extending from the body substantially at right angles with respect to the rib 13. The extension 15, with its head 16, define grooves 17 for receiving said slider. Still further the main body 12 of the male strip carries a flat longitudinally extending flange 18 (similar to flange 10 on the female strip) to enable the male strip to be secured to material by means of an adhesive, or by welding.

The relative positions of the jaw of the female strip, the flange 10, the rib 13 and the flange 18 are such that when the male and female strips are interlocked the flanges 10 and 18 will be substantially coplanar.

It will be understood that when the strut 7 is disengaged from the finger 4 the jaw will be open (or will at least be openable) and the barbed rib 13 may be introduced thereinto, the barbs 14 interlocking with the barbs 5 on the fingers 3,4 once the jaw is closed. Such rib 13 may be retained in the interlocked condition in the jaw of the female strip once the interlocking strut 7 has been introduced into the rebate 9 on the finger 4.

As has been stated hereinbefore grooves are provided for a slider. While it is feasible that the strut 7 could be digitally disengaged from the finger 4 and that the strip forming the fastener could be engaged and disengaged as a result of such digital movement of the strut 7, it is deemed convenient to provide a slider which when moved along the fastener strips in one direction results in disengagement of the locking strut 7 and movement of the finger 4 in a jaw-opening direction and which when moved in the opposite direction results in movement of the finger 4 into a jaw closing position and movement of the interlocking strut 7 into the rebate 9. Such a slider is generally designated 19 in the accompanying drawings.

It will be seen from FIG. 4 that the slider 19 is formed from three parts 20, 21 and 22 which, when connected together by studs 23, define a pair of divergent channels 24 and 25 in which the male and female strips ride. In fact the channels extend substantially parallel to one another over approximately two-thirds of their entire length and only towards one end of the slider 19 do they diverge away from one another.

The open edge portion (that is the lower edge portion) of the channel 24 is provided with a pair of inturned flanges 26 which ride in grooves 17 on the male strip. As will be seen particularly from the cross-sectional views of the slider shown in FIGS. 6a to 6d the cross-sectional shape of this channel 24 remains substantially constant throughout its entire length although the cross-sectional area thereof decreases slightly in a direction extending away from the end of the slider where the channels 24, 25 diverge.

On the other hand, the channel 25 in which the female strip rides, varies considerably in its cross-sectional shape and area. At the end of the slider where the channels diverge such channel 25 is shaped so that it accommodates the female strip when the strut 7 is disengaged from the rebate 9 in the finger 4 and where the jaw 2 is open. The shape of the channel at this end of the slider is shown clearly in FIG. 6a. At the opposite end of the slider the cross-sectional shape of the channel 25 conforms substantially with the cross-sectional shape of the upper part of the female strip when the strut 7 is engaged in the rebate 9 in the finger 4. This latter position is shown clearly in FIG. 6d. However, between the end portions of the channel 25 in the slider 19, the wall of the channel 25 is provided with a lip 27, such lip thickening towards its central portion 28 from its thinner end portions 29. The purpose of this lip is to cause the strut 7 to move towards, or away from, the rebate 9 in dependence upon the direction of movement of the slider 19 along the fastener strips.

It will thus be understood that movement of the slider in one direction draws together the strips and then moves the strut into the rebate whereas movement in the opposite direction moves the strut out of the rebate, opens the jaw, and then separates the strips.

The flanges 10,18 have been described as flanges for securing the fastener strips to material forming, for example, a receptacle. A receptacle designated 30 is shown diagrammatically in FIG. 2, such receptacle being arranged to be closed by a fastener of the form described above.

It will, of course, be understood that such fastener strips may be welded or otherwise attached to sheets of material which are merely to be interlocked and which do not necessarily form a receptacle. However, fasteners in accordance with this invention are expected to have particular application for use as closures for protective covers for a wide variety of equipment which must be protected against deterioration. Such equipment, may, for example, comprise aircraft components, engines of many kinds, projectiles, machine tools and electrical and electronic apparatus which frequently have to be transported and stored (often for long periods of time) and which are liable to corrosion and deterioration in extreme climatic conditions during such transport or storage. The protective covers may, of course, be formed from a large variety of materials but suitable covers are described in British Pat. Nos. 1,013,941; 1,013,211 and 946,466.

In certain applications the fasteners are extremely long and in an endeavor to minimize stretching of one fastener strip with respect to the other such strip when the latter are being interlocked a wire formed from, for example, a metal or nylon, may be introduced into the flanges 10 and 18 or may be sandwiched between such flanges and the material to which they are to be affixed. Naturally such a wire could be incorporated into the edge portion of the material to which the fastener strips are being secured.

Claims

I claim:

1. A strip fastener comprising

1. an elongated male strip,

a. a barbed rib extending laterally along the elongation of the male strip, and

b. a guide for locating a slider on the male strip adjacent the barbed rib; and

2. an elongated female strip arranged adjacent and parallel to the male strip,

c. a pair of spaced-apart barbed fingers extending laterally along the elongation of the female strip, the fingers defining a jaw adjacent and dimensioned to receive the barbed rib of the male strip,

d. one of the fingers being hingedly connected to the female strip whereby the one finger may be moved for opening and closing the jaw, the barbed ri being readily movable into and out of the jaw when the same is open and being locked therein when the same is closed,

e. a locking strut being hingedly connected to the female strip in superposed relation to the one finger,

f. the one finger defining a recess arranged to receive the locking strut,

g. the locking strut having a surface remote from the hinge connection thereof which is shaped for snug engagement with a corresponding surface of the recess, the surfaces of the recess and the locking strut being inclined to one another when out of engagement, and

h. a guide for locating the slider on the female strip adjacent the barbed fingers.

2. The strip fastener of claim 1, further comprising a slider positioned by and movable along the guides for interlocking the strips and separating the same.

3. The strip fastener of claim 2, wherein the one finger and the locking strut are integral with the female strip, strip portions of reduced cross section providing hinged connections of the one finger and the locking strut to the strip.

4. The strip fastener of claim 3, wherein the strips are of deformable material, deformation of the one finger or the locking strut permitting engagement and disengagement of said mutually inclined surfaces.

5. The strip fastener of claim 2, wherein the slider defines a pair of divergent channels engaging the guides, a lip in the female strip guide engaging channel for effecting movement of the locking strut into and out of the recess of the one finger, and the divergence of the channels respectively drawing together, and moving apart, the strips of reverse movement of the slider along the strips.