GB2075828A - Brush knot and brushes incorporating such knots - Google Patents

Abstract

A plurality of filaments 10 is inserted as a bundle 11, by its head end 12, into a collar 13, and an expansion member 14, in the form of a tapering deformable peg, is driven into the head end 12 of the bundle 11 to expand it in the collar 13 which is then shrunk mechanically onto the bundle 11 to form a head on the completed knot. <IMAGE>

Description

SPECIFICATION Brush knot and brushes incorporating such knots This invention concerns brush knots, and brushes incorporating such knots.

A brush knot usually comprises a bundle of filaments, made for example of plastics material (e.g. plastics cord), metal (e.g. wire), hair, fibre, carbon fibre or other strand-like material, which filaments are all anchored together at one end (for convenierice referred to herein as the "head" end) and free at their other ends.In making a brush, a number of such knots (which may be as few as one or may be as many as thirty or forty) are fixed, by their head ends, to a foundation, such as a handle (e.g. in the case of a hand-held single-knot brush or a decorator's painting brush) or a brush back (e.g. in the case of a sweeping brush or the like which fits to a brush stock to enable itto be used manually) or a disc, roller or the like (e.g. in the case of a mechanically-driven brush such as may be employed on a road-sweeping machine or in a machine for brushing workpieces to clean them after mechanical abrasion).

Various ways have already been proposed for anchoring the filaments of a knot together at their head ends, including fusing the material of the filaments at said end and shaping the material to form a head, fastening them together mechanically with staples which serve also to fasten the knot to its foundation in the formation of a brush. These known methods, whilst being adequate for brushes for moderate uses, generally are not particularly suitable for brushes subject to robust or vigorous treatment, e.g. mechanically-rotated road-sweeper brushes, or brushes used in sand-blasting equip mentor brushing or scouring workpieces, after sand blasting, to clean off abrasive particles and material loosened from the surfaces of the workpieces.They have a relatively short useful life, and the methods used for securing the knots usually make it necessary for the entire brush to be replaced, it not being possible for individual knots to be replaced.

An object of the invention is to provide a method of forming filaments into a knot by which the filaments are anchored mechanically sufficiently effectively to make the resultant knot particularly suitable for use in brush constructions, e.g. mechanically-driven brushes, subject to high stresses in use, although the use of the knots is not, of course, restricted to such brushes.

With this object in view, the present invention provides a method of making a brush knot comprising a bundle of filaments anchored together at their head ends, which comprises providing a shrinkable collar around the bundle of filaments at the head ends thereof, driving a tapered expansion member into the end of the bundle at said head ends to expand the bundle so as to locate with the collar therearound, and thereafter shrinking the collar onto the bundle so as to provide a firm anchorage of the collar onto the bundle as a head thereon.

The collar is preferably so disposed on the bundle that a short length of the bundle end projects beyond the collar.

The expansion member is conveniently in the form of a gradually-tapered circular-sectioned or frusto-conical peg. It is preferably of a yielding or deformable material, such as a soft metal or a plastics material, so that shrinking of the collar therearound impresses at least some of the filaments into the surface of said expansion member.

The collar is preferably of metal, such as aluminium, and the shrinkage thereof may simply be effected by mechanical pressing.

Naturally, the invention further includes a brush knot made by the above-discussed method. Such a brush knot comprises, of course, a plurality of filaments arranged in a bundle and having, in the head end of the bundle an expansion member and, around said head end, a collar shrunk onto said bundle and providing anchorage of the filaments between itself and the expansion member.

The invention further provides a brush comprising a foundation to which one or more of the knots aforesaid is secured, the or each said knot projecting through a respective opening in the foundation, which opening has a countersink in which the collar is disposed and retained.

This invention will be described further, by way of example, with reference to the accompanying drawings in which: Figure 1 is a sectional side elevation illustrating components ready for assembly to form a preferred brush knot according to the invention; Figure 2 is a sectional side elevation of the components of Figure 1 assembled together as an initial step in the method of the invention; Figure 3 is a sectional plan taken on the line 3-3 of Figure 2, but showing the assembled components introduced between compression members as a subsequent step in the method of the invention; Figure 4 is a view comparable with Figure 3, but showing the completed knot; Figure 5 is a sectional end view of a completed brush head incorporating a number of the brush knots of Figure 4;; Figure 6 is a sectional end view through one half of a completed roller brush incorporating a number of the brush knots of Figure 4.

In carrying out the method of the invention, in a preferred way, as shown in Figure 1 one starts with a plurality of filaments 10 suitable for making a brush knot. These may be, for example, metal wires or strips, strings, cords, fibres, plastics rods or any other suitable material, and are conveniently of approximately equal lengths. These filaments 10 are arranged in a bundle 11 with their extremities, at one end 12 (the head end), approximately aligned. The head end 12 of the bundle 11 is then introduced into a shrinkable collar 13, provided by a ring of aluminium, so that a short length, of a few millimetres in extent, of the said head end 12 protrudes past the collar 13.

Next, an expansion member 14 is driven into the head end 12 of the filament bundle 11. This expansion member 14 is of nylon, but it may be of other yielding or deformable material, such as a soft metal, e.g. a soft aluminium alloy. The member 14 is in the form of a tapering peg of circular crosssection, the tapering being gradual over most of the peg length and more pronounced at one end to form a tip 15 resembling, for example, the shank of a golfer's tee peg, and it is driven in place by pressing the peg 14, tip 15 first, into the filament bundle end 12, with its axis approximately parallei to the longitudinal axes of the filaments 10, and knocking it into place with a hammer (not shown).

This pperation serves, of course, to expand the head end 12 of the bundle 1 thereby tending to locate the bundle 11 relative to the collar 13 (or vice versa) by being gripped within the latter. Figure 2 shows the resultant assembly 16 with the peg 14 in position. This having been achieved, the collar 13 is shrunk mechanically onto the head end 12 of the bundle 11.This is effected by arranging the resultant assembly 16 so that the collar 13 is disposed between two complementary U-shaped compressing tools 17 as shown in Figure 3, and then bringing the tools 17 together, so as to apply successive pressing operations to the collar 13 as indicated by arrows 30, with stepwise rotation of the collar 13, as indicated by arrow 35, within the tools 17 between the operations so as to cause a progressive shrinkage ofthe collar 13 onto the head ends 12 ofthe filaments 11 which, as a result, become extremely firmly mechanically anchored within the collar 13, between the latter 13 and the peg 14. The collar 13, of course, constitutes a head on the knot 18.Figure 4 is a section through the head 13 of the completed knot 18, showing the shrinkage of the collar 13 around the peg 14, which becomes deformed by the method, and the filament 11 head ends 12 which are also deformed by the method.

A plurality of the knots 18, so prepared, can be assembled onto a foundation to form a brush. The precise form of the foundation will, naturally, depend upon the nature of the brush concerned. Figure 5 shows the case of a simple brush construction comprising a plate-like planarfoundation 19 having a plurality of rows of the knots 18 protruding therefrom, the backplate 20 having therethrough a plurality of apertures or holes 21 each of which is countersunk, and has a respective knot 18 inserted thereon. The head of the knot 13 (which head is provided by the collar 13) is accommodated in the countersink in the hole 21 in which it is retained by a retainer plate 22 which is secured to the backplate, by means of screws 23, to overlie the countersunk holes 21. Such a brush can be used, for example, as a stationary brush past which workpieces are moved in shortblasting or sandblasting apparatus (not shown) to clean the workpieces after blasting. Other forms of foundation may, of course be used to receive the knots, according to their desired construction, but in each case it will have countersunk or counterbored holes for receiving the knot heads as provided by the collars and means for retaining the latter in the countersinks. For instance Figure 6 shows one half of a roller brush comprising a number of the knots 18 protruding from a semicylindrical backplate 24, the knots being held in place by a core half 25. The heads 13 of the knots 18 are located in countersunk holes 26 in the backplate 24 so that the longitudinal axes of the bundle 11 of filaments 10 are radial and perpendicular to the rotational axis of the brush.

Claims (13)

1. A method of making a brush knot comprising a bundle of filaments anchored together at their head ends, which comprises providing a shrinkable collar around the bundle of filaments at the head ends thereof, driving a tapered expansion member into the end of the bundle at said head ends to expand the bundle so as to locate with the collar therearound, and thereafter shrinking the collar onto the bundle so as to provide a firm anchorage of the collar onto the bundle as a head thereon.

2. A method of making a brush knot as claimed in claim 1 in which the collar is so disposed on the bundle that a short length of bundle ends projects beyond the collar.

3. A method of making a brush knot as claimed in claim 1 or 2 in which the expansion member is in the form of a tapered circular-sectional or frustoconical peg.

4. A method of making a brush knot as claimed in claim 1,2 or 3 in which the expansion member is of a yielding or deformable material so that the shrinking of the collar therearound impresses at least some of the filaments into the surface of the expansion member.

5. A method of making a brush knot as claimed in any preceeding claim in which the collar is metal.

6. A method of making a brush knot as claimed in claim 5 in which the shrinking of the collar is effected by mechanical pressing.

7. A method of making a brush knot substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 4 of the accompanying drawings.

8. A brush knot made by the method of any of claims 1 to 7.

9. A brush knot comprising of a bundle of filaments and having, in the head end of the bundle, an expansion member and, around said head end, a collar shrunk onto said bundle and providing anchorage of the filaments between itself and the expansion member.

10. A brush knot substantially hereinbefore described with reference to and as illustrated in the accompanying drawings.

11. A brush comprising one or a plurality of the brush knots claimed in claim 8,9 or 10.

12. A brush comprising a foundation to which is secured one or more of the knots claimed as in claim 8 or 9, the or each said knot projecting through a respective opening in the foundation, which opening has a countersink in which the collar is disposed and retained.

13. A brush substantially hereinbefore described with reference to and as illustrated in Figure 5 or in Figures 6 of the accompanying drawings.