WO1997003272A1 - Brush barrier - Google Patents

Abstract

A brush barrier having an elongate spine (10) formed at least in part of a plastics material, and a band of bristles (20) projecting laterally from a channel (11) defined by the spine (10); wherein an edge of the band (20) is retained in the channel (11) by heat bonding between an inner surface region of the channel (11) and an element (13) of a plastics material which is compatible, for the purpose of heat bonding, with the plastics material of the spine (10); and wherein the element (13) is mechanically secured to the band (20) along said edge thereof.

Description

BRUSH BARRIER The invention relates to an improved, elongate brush barrier, and to a method of producing such brush barrier.

Elongate brush barriers are well known and are utilised in a wide variety of commercial, domestic and industrial applications. Brush barriers comprise an elongate, relative narrow brush having backing or spine to which is secured a band of bristles. They are used extensively as draft seals around doorways and windows, light seals around doorways for dark rooms, automotive weather seals, and the like and may be used to seal out air, water, light, vermin, birds, sound, dust, leaves, snow or the like. Elongate brush barriers also are used as spray suppressants around wheel arches of heavy vehicles. They are also used as sweeping or scrubbing brushes for road sweepers, car washes, food processing apparatus, cleaning brushes for conveyors and the like. They are used extensively as seals around aerobridges, scourers, spiral conveyors for fragile goods, electronic conductors, electromagnetic gasketting, just to name a few.

Conventional elongate brush barriers generally have their bristles retained in a spine comprising an elongate U-shaped channel member. In one known form, the channel member is of metal and is crimped or deformed so as to grip and retain a ribbon of transverse bristles along one edge of the ribbon such that, in the finished brush barrier, the bristles project from the channel as a substantially continuous band. With use of a metal channel member the bristles can of any suitable natural material such as horse-hair, or of any suitable synthetic material such as nylon or polypropylene. However, a metal channel member is relatively expensive and, in general, it is too rigid for many applications.

In another known form of brush barrier, the channel member is of synthetic plastics material and is applied along and is heat bonded to one edge of a ribbon of transverse bristles, such as by application of hot air jets. With this form of brush barrier, the channel member is both inexpensive and flexible and, for materials able to be used, the heat bonding is relatively easily achieved. However, a major disadvantage of this form is that the materials for the channel member and bristles are limited. A first factor is that, for heat bonding, the material of which the channel member is made must be compatible for the purpose of heat bonding with the material of the bristles. Thus, by way of example, it is not possible to heat bond effectively a polypropylene channel member to nylon bristles. A second factor is that it is not possible to heat bond effectively a channel member of a plastics material to natural bristles such as horse-hair. A further factor is that, even when the materials of the channel member and the bristles are the same, effective heat bonding can necessitate use of air jet temperatures which are difficult to attain and/or to control so as to avoid damaging the channel member and/or the bristles.

The present invention seeks to overcome the limitations in the known forms of brush barrier, enabling use of a wider variety of plastics materials for the channel member with a wider variety of bristle materials.

In one form, the invention provides a brush barrier having an elongate spine formed at least in part of a plastics material, and a band of bristles projecting laterally from a channel defined by the spine; wherein an edge of the band is retained in the channel by heat bonding between an inner surface region of the channel and an element of a plastics material which is compatible, for the purpose of heat bonding, with the plastics material of the spine; and wherein the element is mechanically secured to the band, along said edge thereof.

By the term "band" as used herein the description and claims we mean an array of multiple bristles which form a ribbon or band of transverse bristles. The element may be of a plastics material which is the same as that of the spine. However, some different plastics materials are compatible so as to be able to be secured together by heat bonding, and the spine and the element therefor may be heat bonded by the use of such different materials.

The invention has its principal application in providing a brush barrier having a spine and bristles of respective materials which are not compatible for the purpose of heat sealing. However, the invention also can be used to advantage where the spine and the bristles are of the same material, or of respective materials which are compatible for that purpose. When the spine and the bristles are of the same material, or of the respective materials which are compatible, the brush barrier again has heat bonding between the spine and the element. However, securement of the bristles can be enhanced by their heat bonding to the element and/or directly with the spine. The manner in which the element is mechanically engaged with the one edge of the band can take a variety of forms. However, before elaborating on these, further description first will deal with the form of the band, and to the reference to one edge thereof.

Where the bristles material is available as continuous thread, of yarn or monofilament, the band is formed continuously, using a suitable machine. With such machine, an oscillating head lays down at least one continuous thread, usually a plurality of continuous threads, as closely adjacent weft threads across a width required for a given band. As the band forms by this procedure, at least one and preferably at least two retaining warp threads of a suitable material are applied, such as by stitching, to secure the weft threads in substantially parallel relationship. One side of the resultant band has the spine applied to it, and the other side may be cropped before, after or during application of the spine and its securement by heat bonding. However, in some cases, the one band is slit, such as centrally between two adjacent retaining warp threads, with a respective spine so applied to each side of the band before, after or during such slitting.

In a first arrangement according to the invention, the element comprises at least two threads, of yarn or monofilament, which are applied as stitching to provide warp threads along the one edge of the band. In being stitched to the band, the threads providing the element are mechanically engaged with the band, by each thread being along a respective one of opposed main faces of the band, at or adjacent to the one edge, and interlocked with the other through the band.

In a second arrangement according to the invention, at least one thread may be woven into the band, as a warp thread, as the band is formed.

In a third arrangement according to the invention, the element comprises a narrow strip of plastics material which is secured along the one edge of the band. Preferably the strip of plastics material extends beyond and is folded around the one edge so that a respective margin of the strip overlies each of the opposed major faces of the band at the one edge thereof. The strip then is able to be stitched to the band, by application of suitable warp threads which interlock through the band. While the strip is to be a plastics material which is compatible with the spine, for the purpose of heat bonding, the stitching threads by which the strip is secured at its margins may be compatible or incompatible for that purpose.

In a variant of the third arrangement, the element may comprise a respective narrow strip of plastics material applied to the band, at the one edge, over each of the opposed major surfaces of the band.

In the first arrangement of the invention, the threads comprising the element, and forming a warp thread, preferably interlock the bristles in successive adjacent groups or bundles. Except where the threads interlock between the groups or bundles of bristles, they are exposed at each of major surfaces of the band adjacent to the one edge. Thus, on application of the spine to the one edge, the element is received within the channel of the spine and the threads comprising the element are in contact with side surfaces defining the channel. The situation is similar with the second arrangement of the invention. In each case, application of heat energy, such as by hot air jet, achieves good heat bonding between the element and the spine and, due to mechanical engagement of the element with the band, securement of the band at its one edge in the spine. As indicated, this securement is enhanced if, like the element, the bristles of the band are compatible with the material of the plastics material for the purpose of heat bonding.

The situation is similar with the third form, and the variant thereof. That is, on application of the spine to the one edge of the band, a respective margin or respective strip of the element is in contact with each side surface defining the channel, enabling heat bonding to proceed therebetween. Again, bonding between the element and the spine secures the band to the latter, due to mechanical engagement between the element and the band. In the variant of the third arrangement, it can be beneficial to have an edge of each strip of the element located beyond the one edge of the band, to enable that edge to be folded across the one edge as the spine is applied thereto. This folding can preclude one or each edge of the strips from lifting from the band so as to impede application of the spine.

In a modification of the third arrangement of the invention and its variant, the element may be adhesively bonded to the band at the one edge, and thereby mechanically engaged therewith. In this regard, it will be appreciated that different plastics materials which are not compatible for the purpose of heat bonding can be compatible for adhesive bonding. Thus, a plastics material for the element which is not compatible with the material of the band for the purpose of heat bonding, can be adhesively bonded with use of a suitable adhesive. However, it is to be appreciated that compatibility for adhesive bonding need not be limiting since an adhesive which is compatible with the element but not with the material of the band, still can achieve adhesive bonding between the element and the band by the adhesive encapsulating the bristles of the band at the one edge. As with the element of the third form, and its variant, secured by stitching, securement of the element by adhesive bonding then can be followed by application of the spine to the one edge and effecting heat bonding between the spine and the element.

In the modification of the third arrangement, the adhesive may be applied to the band at the one edge, to the element, or to both the band and the element, prior to or in the course of applying the element to the band. The adhesive may be of a cold curing or hot-setting type and, in the latter case, setting of the adhesive can be as a consequence of heat energy applied for the purpose of heat bonding of the spine to the band.

Of course, while direct heat bonding of the spine to the one edge of the band is not appropriate where the material or respective materials are not compatible with this, direct adhesive bonding can be possible. That is, adhesive bonding may be possible without recourse to an element mechanically secured to the band, although this is outside the scope of the present invention. However, such direct adhesive bonding, in contrast to adhesively securing an element to the band and then heat bonding the spine thereto, has some major disadvantages. A principal disadvantage is in the difficulty, relative to the procedure of the invention, of providing a sufficient, uniform application of adhesive for adhesive bonding, without the adhesive being displaced onto the band or spine exteriorily of the channel, or onto devices for feeding the band and/or the spine into contact. As will be appreciated, application of the spine to the one edge of the band is an operation conducted in a relatively high speed machine. Application of a uniform, sufficient quantity of adhesive to one or each strip comprising the element, for example, is an operation which more readily is able to be controlled than application of adhesive into the relatively narrow channel of the spine.

One principal application of the present invention, is in providing a brush barrier having a spine of polypropylene and bristles of nylon, such as nylon monofilament. It previously has not been possible to produce a brush barrier of this nature, since polypropylene and nylon are not compatible for the purpose of heat bonding. Also, this combination of plastics is not one which is readily amenable to direct adhesive bonding. Moreover, a seemingly similar brush barrier having a spine and bristles each of nylon can not be effectively produced on a commercial basis, due to the high temperatures necessary for heat bonding and, again, the difficulties of direct adhesive bonding.

The spine may comprise a channel member of plastics material. The channel member may be formed by extrusion and, as formed, define the channel along its length. Alternatively, the spine may comprise an elongate strip-like member which is folded along a Iongitudinal line so as to define the channel. The strip-like member may be folded, to define the channel, prior to or in the course of application to the edge of the ribbon or band which is to provide the bristles.

Where the spine comprises an elongate, strip-like member, it may be formed of the plastics material. Alternatively, it may be formed of another material which is provided with a coating of plastics material. A number of different arrangements are possible, as detailed in the following. In one arrangement, the strip-like member comprises or includes a ribbon-like strip. In one form, the strip comprises the plastics material. In another form, suitable for a brush barrier required in a form with a rigid spine, the ribbon-like strip is of another material, such as a metal, which is coated with the plastics material.

In a further arrangement, in which the ribbon-like strip may be of a perforated form, it is formed of an elongate member or members which are foimed into a strip form by being laid down and secured in a sinuate configuration. In one form, the strip is formed of thread, such as monofilament, of the plastics material which is laid down in a sinuate configuration and secured in such configuration by interlocking, longitudinally extending threads which also may be of the plastics material. In another form, the strip is similarly formed of threads or strands of a different material, such as metal wire, which is laid down in a sinuate form, secured in that form by interlocking threads which may be of the plastics material. In a variant of the latter form, the threads or strands are coated with the plastics material, either before being laid down in the sinuate configuration or thereafter. Where the coating is applied after that configuration is achieved, it assists in securement of the threads or strands, while it also can result in the strip-like member being substantially continuous and imperforate.

With either arrangement, the strip-like member to comprise the spine typically is relatively narrow, compared with the width of the ribbon or band providing the bristles. Also, where the strip-like member includes thread or strand laid down in a sinuate configuration, that configuration can have a relatively open form compared with the ribbon or band providing the bristles. Thus, while the ribbon or band providing bristles usually is substantially continuous, successive transverse parts of the sinuate configuration can be spaced from each other longitudinally of the strip-like member.

Extensive trials have been conducted, based on the present invention, and resulted in the production of high quality brush barrier using industrial apparatus. The barrier was produced in substantial length by using continuous lengths of a spine comprising a channel member and of a band of bristle forming weft thread which, after heat bonding together, were cut to required lengths for the barriers. The channel member was of extruded polypropylene, while the weft thread of the band was nylon monofilament secured by retaining warp threads of polyester, although the retaining warp threads could have been of nylon, cotton or other convenient yarn. Previous attempts by us and others have failed to establish heat bonding between a band of nylon weft threads and a polypropylene channel member. However, in the trials, the edge of the band to which the channel member was to be secured was modified by incoφorating stitched warp threads of polypropylene along major faces of the band, closely adjacent to that edge. Despite the incompatibility of the channel member and weft threads for the purpose of heat bonding, it was found that very effective securement of the channel member to the band was achieved in the trials on a continuous basis and at commercial production rates. The securement was by heat bonding of the polypropylene warp thread stitching provided along the one edge of the band, closely adjacent to the one edge thereof, and opposed side surfaces of the channel. From the trials, it was apparent that the polypropylene warp threads which comprised the element providing heat bonding could, with comparable results, be either yarn or monofilament threads.

In the above description, there is description of the production of a band in which the weft threads are to provide bristles in resultant brush barriers. That description is in relation to the production of a band using continuous thread to provide the weft threads. However, a suitable band also can be made for the purpose of the present invention by using discontinuous thread or fibrous material such as horse hair. A band of such discontinuous material can have the material laid down and secured as weft threads each of which is separate from other weft threads, but retained in relationship to each other by suitable retaining warp threads until a spine is applied. A band of this form can have a spine applied to it and secured by heat bonding in accordance with the present invention, most preferably by an element comprising thread applied by stitching. However, despite good heat bonding being achieved between the element and the spine, securement of the discontinuous weft threads to comprise bristles can be inadequate for some purposes, particularly where there is a relatively thick packing of bristles laterally of the channel of the spine. It therefore is preferred that a modified form of band be used where its weft threads are of discontinuous thread or fibrous material.

In producing the modified form of band, the discontinuous material for the weft threads is laid down and secured by retaining warp threads in an arrangement in which, depending on the lengths in which the material is available, individual threads or fibres are folded end for end at least once to provide a plurality of weft threads of each thread or fibre. The arrangement is such that, along the edge of the resultant band to which a spine is to be applied, each thread or fibre of the discontinuous material provides at least one bend or loop joining adjacent weft threads. Thus, in providing the warp threads to comprise the element by which the spine is to be secured by heat bonding, those warp threads are more positively interlocked with the weft threads and are more securely retained in a resultant brush barrier. In the foregoing description, there is reference to the element, in one arrangement according to the invention, comprising warp threads. Also, in the formation of the band of which weft threads are to provide bristles in a resultant brush barrier, other, retaining warp threads are used. The retaining warp threads can be of any suitable material, having regard to cost. They are further distinguished from an element comprising warp threads in that, while the latter are integrally incorporated by heat bonding in the channel of the spine, the retaining warp threads are simply to hold the weft threads until application of the spine. Prior to installation of a brush barrier for a required application, the retaining warp threads usually are removed to free the bristles. The spine preferably is configured to facilitate mounting of the brush barrier for use in a required application. Thus, in addition to defining a channel, it usually has a cross-section enabling it to be located and retained in a groove or the like of a mounting structure. Thus, for example, in the case of a spine comprising an extruded channel member, it may have a laterally open groove in the outer surface of each of opposed side walls which define the channel. Alternatively, it may have a T-shaped mounting portion with the end of the stem of that portion integral with a base wall defining the channel, and the head of that portion spaced from the base wall.

An advantage of a brush barrier having a spine of a plastics material is its overall flexibility compared with a metal spine. This advantage is retained in a brush barrier according to the invention, except where, as indicated, the spine is of a plastics coated metal strip. However, even in the case of a plastics coated metal strip, the gauge necessary for the metal can be less than required where a rigid, crimped or deformed metal spine is used and, thus, can allow for some bending out of a plane parallel to the bristles. In order that the invention may more readily be understood, the description is now directed to the accompanying drawings, in which:

Figure 1 provides a partial perspective view of a brush barrier according to the invention during the assembly process.

Figure 2 provides a partial perspective view of a brush barrier according to the invention.

With reference to figures 1 and 2, the brush barrier includes an elongate spine 10 which part thereof defines channel 11. A band of bristles 20 projects laterally from the channel.

Figure 1 illustrates the brush barrier during the assembly process. At the stage shown additional warp threads 12 and 13 are shown which have been used to hold the band of bristles during the application of the spine to the edges thereof. After the application of the spine to the edges bristles are secured at a point approximately equidistant from the spines and the additional warp threads are removed. Thus two brush barriers are produced from an original single band of bristles.

Finally, it is to be understood that various alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the spirit or ambit of the invention.

Claims

1. A brush barrier having an elongate spine formed at least in part of a plastics material, and a band of bristles projecting laterally from a channel defined by the spine; wherein an edge of the band is retained in the channel by heat bonding between an inner surface region of the channel and an element of a plastics material which is compatible, for the purpose of heat bonding, with the plastics material of the spine; and wherein the element is mechanically secured to the band, along said edge thereof.

2. A brush barrier according to claim 1 wherein the element comprises at least two threads, of yarn or monofilament, which are applied as stitching to provide warp threads along the one edge of the band.

3. A brush barrier according to claim 1 wherein the element comprises at least one thread, of yarn or monofilament, which is woven into the band, as a warp thread along the one edge of the band.

4. A brush barrier according to claim 1 wherein the element comprises a narrow strip of plastics material which is secured along the one edge of the band.

5. A brush barrier according to claim 4 wherein the strip of plastics material extends beyond and is folded around the one edge of the band so that a respective margin of the strip overlies each of the opposed major faces of the band at the one edge thereof.

6. A brush barrier according to claim 5 wherein the strip of plastics material is stitched to the band by a warp thread which extends through the band and the sections of the plastics strip that overlies each of the opposed major faces of the band at the one edge thereof.

7. A brush barrier according to any one of the preceding claims wherein the band of bristles comprise a band of polymer weft threads.

8. A brush barrier according to claim 7 wherein the polymer weft threads are nylon weft threads.

9. A brush barrier according to any one of the preceding claims wherein the elongate spine of the channel member is formed from polypropylene.

10. A brush barrier substantially as hereinbefore described with reference to the drawings.