GB2268682A - Brush segments and rotary brushes - Google Patents

Abstract

A brush segment (14, Fig.1) for assembly on a shaft to form a rotary brush comprises a drive plate (21, Fig.1) provided with ventilation apertures 32. Associated with the apertures are flaps 34 which distribute cooling water provided at the centre of the plate and also enhance airflow through the passages defined by aligned apertures 32. The segment (14, Fig.1) is dual purpose and may be assembled to provide staggered fill or finger brush format. Further disclosed is a brush segment in which the drive plate is keyed or otherwise formed, to enable the segment to be assembled on the shaft in at least two different orientations. <IMAGE>

Description

BRUSH SEGMENTS AND ROTARY BRUSHES This invention relates to brush segments and to rotary brushes made up of said segments.

In a known form of rotary brush alternate left- and right-hand segments each made up of a plate with an even number of "knots" or collections of outwardly directed bristles are assembled onto a keyed drive shaft. The segments are compressed axially to form a brush with a socalled "staggered fill" in which each knot lies midway between two knots on the adjacent segment, to give a high density brush. The drive shaft is hollow and perforated to allow a supply of water to be flung out centrifugally to cool and clean the bristles. The bristles are often made of a synthetic plastics material impregnated with an abrasive and so the term bristle should be construed broadly.

We have found several problems with the known form of brushes; the need to stock left- and right-hand segments creates storage problems and the possibility of incorrectly assembling the brush if there are insufficient segments of one type. Also the distribution of the water outwardly to the bristle knots of the brush is often inadequate which leads to poor cooling and poor performance of the brush as the material properties of the bristles are adversely affected by increased temperatures and the brushes can clog if the flow of water is insufficient.

There are brush segments on the market which include a series of part-annular slots which define ducts through which air is circulated in use. However these slots are passive in the sense that they do not enhance distribution of air or water.

Accordingly, in one aspect, this invention provides a brush segment for assembly with other like segments along a drive shaft to form a generally cylindrical rotary brush, said segment comprising a plate means having a central drive aperture, and a plurality of outwardly directed bristle knots disposed circumferentially around said plate means, said plate means including a plurality of ventilation apertures inwardly of said bristle knots, at least some of said apertures having flow distribution means associated therewith for enhancing circulation of cooling air and/or distribution of water through the segment.

The ventilation apertures and flow distribution means may take many forms. In one example, the ventilation apertures may comprise part-annular slots and the flow distribution means may comprise oppositely directed tabs at each end of the slot. When the rotary brush is rotated in use, the tabs will tend to scoop air into the elongate ducts defined by the aligned ventilation apertures and cause it to flow along these ducts. Likewise the tabs will tend to deflect water travelling outwardly from the shaft.

In another example, the slots may be thin radially directed slots and the distribution means may comprise a flap associated with each slot, for example up-standing from one side of the slot. This example also will scoop air into the assembled brush from one end and convey air axially through the brush. Also, the flaps will tend to distribute the water supplied from the central shaft. Furthermore, in circumstances where cooling water is not available internally or externally, the brush filaments will benefit from the much improved air cooling effect created by the tab design.

This may considerably extend brush life especially where the bristles comprise a synthetic material such as nylon filaments.

The slot and flap may be formed by punching and folding a flap out of the plate means. The flap is preferably dished or curved in the radial direction to deflect incident water in two directions.

The radial slots are preferably spaced at twice the pitch of the bristle knots with alternate slots being directed to the base of a bristle knot.

According to another aspect of this invention, there is provided a brush segment for assembly with other like segments along a drive shaft to form a generally cylindrical rotary brush, said segment comprising an inner drive element or plate keyed or otherwise formed so that it can be assembled on said drive shaft in at least two different orientations to allow adjacent segments to be staggered with respect to each other so that each bristle knot on a plate lies at a radial position between two knots on an adjacent plate.

In the known form of rotary brush referred to above, the drive shaft has diametrically opposed keys but the knots are symmetrically arranged with respect to both keys and so although the segment can be assembled in two different orientations, the orientation of the knots does not change.

Thus it is preferred for the brush segment of this invention to have an odd number of equispaced knots and two diametrically opposed keyways so that it may be assembled on existing shafts in two different orientations by indexing it through 1800. Because of the odd number of knots, a "staggered fill" can be achieved with just one type of segment by indexing alternate segments through 1800. However, if a lower density finger type of brush is required all the segments may be assembled in the same orientation.

This multiple configuration means that a manufacturer or operator need only keep segments of one type rather than left- and right-hand segments.

The same effect may be achieved by using an even number of bristle knots with an asymmetric dual key way arrangement or by using an even number of knots and a diametrically opposed keyway disposed at one quarter the pitch of the knots, relative to an axis of symmetry of the knots. There are many other ways of achieving this result, which will be apparent to one skilled in the art given the above enabling examples.

In the above examples, the periphery of the drive aperture may be interrupted or castellated to provide better access for water leaving the central shaft.

The invention also extends to a rotary brush made up of a plurality of segments as defined above.

Whilst the invention has been described above, it extends to any inventive combination of features set out above or in the following description.

The invention may be performed in various ways, and two embodiments will now be described by way of example only, reference being made to the accompanying drawings, in which:- Figure 1 is a schematic view of a part-constructed rotary brush made up of a plurality of brush segments in accordance with the invention; Figure 2 is a plan view of part of a first embodiment of brush segment, Figure 3 is a section view taken on lines III-III on one of the ventilation ducts formed by the aligned ventilation apertures when the segments of Figure 2 are assembled; Figure 4 is a view of part of a second embodiment of brush segment; and Figure 5 is a section view taken on lines V-V on adjacent ventilation ducts formed by the aligned ventilation apertures when the segments of Figure 4 are assembled; Referring initially to Figure 1, the rotary brush 10 comprises a hollow perforated drive shaft 12 on which is assembled a stack of brush segments 14. The shaft 12 is rotated to turn the brush in use and a supply of water is fed to the interior of the shaft to be flung centrifugally out of the perforations 16. The shaft has two diametrically opposed keys 18 which locate in keyways 20 in the plates 21 of the segments 14. The segments 14 have an odd number of equispaced bristle knots 22 and inwardly therefrom a flow distribution system 24, various forms of which will be described below.In both illustrated embodiments, the key/keyway arrangements 20/21 allow the segments 14 to be assembled in either of two different orientations, 1800 apart. This, in conjunction with the equispaced odd number of knots 22 means that the segments can be assembled in two different formats, to provide either a staggered fill format or a low density finger brush format, depending on the particular application.

In the staggered fill format a bristle knot 22 on one segment lies circumferentially midway between two bristle knots on the next segment, with alternate segments having the same angular orientation so that a high density fill is obtained. In the finger brush fill, all the segments on the brush have the same angular orientation, and so the knots on adjacent segments are in axial alignment.

The dual orientation segment capability may be achieved in different ways. As shown here there may be an odd number of equispaced knots and the diametrically opposed keyways may be aligned with an axis of symmetry of the knots so that the half pitch offset configuration is obtained by indexing the segment 1800 about the drive axis. Alternatively there may be an even number of equispaced knots and the plates 21 may each have keyway arrangements which may be assembled in either of two angular orientations on the drive shaft to provide the required facility for angular offset between adjacent segments. In some circumstances, it may be possible to turn the plate over to obtain the other configuration instead of indexing it through an angle.

Referring to the first embodiment of Figures 2 and 3, the flow distribution system comprises a series of partannular slots 24 with alternately directed upward and downward tabs 26,28 respectively at each end of the slot. As seen in the section view of Figure 3, the slots 24 of the assembled segments define a series of axial ventilation ducts 30 and the tabs tend to scoop air into and cause it to flow through the duct 30. They may also improve the distribution of water through the knots 22, by deflecting it around the bristles as it passes out of the drive shaft perforations 16.

Referring to the second embodiment of Figures 4 and 5, the ventilation system here comprises a series of radial slots 32 at twice the pitch of the knots 22, with each knot having a slot directed at its base (apart from where the keyways 20 make this impractical). The slots are made by punching and folding out a flap 34 which acts in a similar manner as the tabs of the previous embodiment. Thus the flaps 34 scoop air into and cause it to flow along the ducts 36 defined by the aligned radial slots 32, and enhance water distribution through the knots. As best seen in Figure 4, the flaps are curved relative to the radial direction to improve flow distribution.

A variety of forced ventilation methods may be used to augment air flow through the ventilation ducts. An air box (not shown) may be attached by a suitable sliding seal to either end of the assembled brush. The box at one end may blow air in whilst the box at the other end may suck it out.

Alternatively there may be just a suction device or a blower at one end. The air may be suitably refrigerated or conditioned to prolong the life of the bristles.

Claims (16)

1. A brush segment for assembly with other like segments along a drive shaft to form a generally cylindrical rotary brush, said segment comprising a plate means having a central drive aperture, and a plurality of outwardly directed bristle knots or collections of bristles disposed circumferentially around said plate means, said plate means including a plurality of ventilation apertures inwardly of said bristle knots, at least some of said apertures having flow distribution means associated therewith for enhancing circulation of cooling air and/or distribution of water through the segment.

2. A brush segment according to Claim 1, wherein said flow distribution means includes elements or portions thereof which project generally laterally from the plane of the plate means.

3. A brush segment according to Claim 1 or Claim 2, wherein the ventilation apertures comprise part-annular slots.

4. A brush segment according to Claim 3, wherein the flow distribution means comprise oppositely directed generally lateral tabs at opposite ends of each slot.

5. A brush segment according to Claim 1 or Claim 2, wherein the ventilation apertures comprise radially directed slots.

6. A brush segment according to Claim 5, wherein the distribution means comprises a flap associated with each slot upstanding from one side of the slot.

7. A brush segment according to Claim 6, wherein each flap is dished or curved in the radial direction.

8. A brush segment according to Claim 5, wherein alternate slots are directed to the base of a bristle knot or collection of bristles.

9. A brush segment according to any preceding claim, wherein the bristles are made of a synthetic plastics material.

10. A brush segment for assembly with other like segments along a drive shaft to form a generally cylindrical rotary brush, said segment comprising an inner drive element or plate means supporting around its circumference a plurality of bristle knots or collections of bristles, the drive element or plate means being keyed or otherwise formed so that it can be assembled on said drive shaft in at least two different orientations to allow the bristle knots or collections of bristles on adjacent segments to be staggered with respect to each other.

11. A brush segment according to Claim 10, wherein the brush segment has an odd number of equispaced knots or collections of bristles and two diametrically opposed keyways so that it may be assembled on existing shafts in two different orientations by indexing it through 180 .

12. A brush segment according to Claim 9, wherein the brush segment has an even number of bristle knots or collections of bristles with a keyway arrangement allowing assembly in either of at least two different orientations.

13. A brush segment according to any preceding claim, wherein the segment includes a drive aperture at least a major portion of which is interrupted or castellated.

14. A rotary brush made up of a plurality of brush segments according to any of the preceding claims.

15. A brush segment substantially as hereinbefore described with reference to and as illustrated in any of the accompanying drawings.

16. A rotary brush segment substantially as hereinbefore described with reference to and as illustrated in any of the accompanying drawings.