US3139641A - Cylindrical brush construction - Google Patents

Description

uly 7, 1964 J. E. GROGAN ETAL CYLINDRICAL BRUSH CONSTRUCTION 3 Sheets-$heet 2 Filed June 22, 1961 S A mm T m T V55 A mmm EA July 7, 1964 Filed June 22, 1961 J. E. GRQGAN ETAL CYLINDRICAL BRUSH CONSTRUCTION 3 Sheets-Sheet 3 INVENTORS:

JUHN E. 5120mm. EERARD A. P111255 AN.

United States Patent This invention relates to cylindrical rotary brushes. More particularly, it relates to rotary brushes having the bristles fixed to semi-cylindrical shells which shells may be easily removed from their driving mechanism for repair and replacement.

At the present time there are many applications for cylindrical rotary brushes in assembly line operations, in job shop operations, cleaning and finishing and abrading operations, in specialty operations, and in floor polishing units. Examples of the assembly line operations include a belt type conveyor cleaner brush where a sheet of plastic is to have its surface dulled or roughened by a stiff bristled cylindrical rotary brush mounted horizontally above a conveyor table on which the plastic sheet is moved.

Since these rotary brushes require a driving shaft, previously when it was required to replace the brushes, it was necessary to shut down the entire machine and dismantle the shaft from the driving mechanism to replace the brush. This replacement operation often was further complicated in that the brushes were so attached to the shaft that replacement required installing a completely new shaft which also meant that a replacement brush was heavier and more expensive than necessary.

Accordingly, it is an object of this invention to produce an eflicient, simple,-effective, economic, and easily replaceable vibration proof brushing unit for cylindr'cal drive shaft rotary brushing installations.

Another object of this invention is to provide a disposable cylindrical brush unit which may be utilized as an original replacement brushing part for installationwithout requiring dismantling of the driving mechanism, removal, and/ or, if desired, even altering of the driving and supporting shaft therefor.

A further object is to provide an integralcylin'drical brush unit which is light in weight, is chatter free, is preformed, and is pre-set to be clamped on a cylindrical driving and mounting cylinder or shaft, so that the alignment of the ends of the bristles or brushingelements of the outer cylindrical surface of the brush will .not be detrimentally affected by centrifugal and/ or twisting forces applied to the brush during its rotation.

Still a funther object of this invention is to provide an improved and simple method for'fabrication of such lightweight disposable cylindrical brushingunits.

Generally speaking, the cylindrical brush assembly of this invention comprises a central rotating drivingand' supporting cylinder or cylinders having a circumferentially continuous smooth cylindrical outer surface upon which surface is clamped a pair of complementary-substantially semi-cylindrical brush supporting shells. Each of these semi-cylindrical shells may comprise extruded elements having integral longitudinal radial ribs along their outer surfaces between pairs of which ribs are clampedbrushing strips. These extrusions or shells may be straight and parallel to the axis of rotation of the brush, or they may be twisted, up to as much as about one half revolution from one end to the other for assembly without removal of the cylindrical brush support or its shaft, to provide a chatter free design forming a helical pattern for the radial ribs and brush strips clamped between said ribs.

The separate brushing strips may have bristles, cloth or felt strips folded and mounted in a backing channel either by a retaining wire holding the :U-shaped elements "Ice in a metal or plastic channel, or they may have the bristles molded into a metal or plastic backing piece, which backing channel or piece may be clamped between adjacent pairs of ribs by crimps along said ribs.

The semi-cylindrical ribbed shells may have their ribs removed in circumferential bands, usually at their ends for locating circumferentially tightenable hose-type clamps for anchoring the pair of shells against the circumferentially continuous cylindrical surface of the driven shaft or cylinder of the brush mechanism. The use of the circumferentially tightenable clamps in conjunction with the extruded brush shells provides a simple and effective means of replacing worn brush elements in a brush machine without removing, changing or even drilling the shaft upon which they are mounted. However, if desired, in place of or in addition to these clamps, the brush shells and supporting shaft may be diametrically drilled at their ends and/or intermediate their ends, if there is sutlicient spacing provided or cut out between the ribs, for locating tie bolts with nuts extending from between pairs of ribs on one shell to a diametrically similar location between pairs of ribs on the other shell. Such intermediate diametrically located bolts may be employed also to prevent the central portions of the shells from being bowed outwardly by centrifugal force when the brush assembly is rotated. These bolts, however, are placed near the edges of the shells.

The above mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of embodiments of this invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevation in partial longitudinal section of an alternate form of a brush assembly mounted on a horizontally supported and gear driven smooth cylinder o-r hollow roller;

FIG. 2 is an enlarged cross-sectional view taken along line II-ll of FIG. 1 showing the circumferentially tightenable hose-clamp type shell clamping means of this invention and disclosing the individual brush strips between pairs of radial integral ribs on each shell; 7

FIG. 3 is an enlarged sectional detail view showing a pair of crossed tie bolts in association with the ends of the pair of shells which serve as an alternate form of shell clamping means;

FIG. 4 is a reduced perspective View of a pair of the extruded semi-cylindrical strip brush holding shells of the alternate form of this invention with spaced pairs of converging ribs and with said radial ribs machined away at their ends to provide clamp seating plain circumferential end portions;

FIG. 5 is a perspective view, similar to FIG. 4, of the preferred form of the extruded shells of this invention wherein the shells have been pre-formed and set into a one half turn twist throughout their length to provide a helical pattern for the brush strips;

FIG. 6 is a longitudinal sectional view with parts broken away showing the preferred embodiment of the invention mounted on trunnions in place of a through shaft and illustrating heads of a pair of crossed tie bolts between long half-turn twisted shells which tie'bolts serve to prevent outward bowing of the brush shells by centrifugal action during rotation thereof;

' FIG. 7 is a sectionaldetail view taken along line VIL- VII of FIG. 6 showing pairs of spaced converging ribs similar to those shown in FIGS. 4 and 5;

FIG. 8 is an enlarged vertical sectional and perspective detail View through a brushing strip element in which several plies of a folded non-woven fabric are employed instead of bristles; V

FIG. 9 is a perspective view of a nut which may be 3 utilized with the through bolt shown in FIGS. 6 and 7;

FIG. 10 is a fragmentary view similar to FIG. 6, but illustrating the clamping means applied directly over the ribs in the center of the brush instead of the diametrical tie bolts for preventing outward bowing of the brush shells and showing an inner collar against which the inner clamping may be limited;

FIG. 11 is an enlarged end view of a brush supporting shell having integral ribs in spaced pairs similar to that shown in FIGS. 4, 5 and 7 and showing the circumferential extent of the shell;

FIG. 12 is a reduced end view of a still further form of rib structure particularly for brush structures of the smaller sizes;

FIG. 13 is a side elevation of one of the extruded shells of the form shown in FIG. 5 and illustrating the maximum twist permissible for assembly without removal of the supporting structure from the machine;

FIG. 14 is an end view of the extruded and twisted shell shown in FIG. 13;

FIG. 15 is a perspective view of one of the extruded shells of the form shown in FIG. 4 prior to having the ends of the ribs machined off; and

FIG. 16 is an enlarged perspective fragmentary view of a partially assembled portion of an extruded shell element, similar to that in FIGS. 1 and 2, showing two of the individual brush strips clamped between adjacent double integral radial ribs of the extrusion by crimps or spreading the center V of said double ribs.

(I) SHAFT Referring to FIG. 1 the brush assembly is shown mounted on a shaft 21 which may have bearing portions 22 at each end journalled in bearings 23 mounted in yoke 24 of a brushing apparatus or machine. The shaft 21 may be of constant diameter between the end portions 22 or it may have integral, keyed or shrunk-on wheels, cylinders, or rollers 25 adjacent and/or between the bearing ends 22, which cylinders or rollers also may be bridged by a tube or sleeve 26 to form a rotating drum or hollow roller. The importance of having a cylindrical section between the bearing portions 22 is that a smooth continuous outer cylindrical surface 27 must be provided for support and clamping of the brush shells 40, at least at the location of the clamps for said shells.

A gear 28 may be shrunk on or keyed to the shaft 21 as a driving means for the shaft which gear may be driven by a corresponding gear or sprocket chain (not shown). Intermediate the short cylinders or wheels 25 on the shaft 21 there may be mounted one or more auxiliary cylinders or wheels 30 providing an outer diameter complementary to that inside said shells 40, which intermediate or auxiliary wheel or wheels may be mounted onto the shaft 21 and/or may have two adjacent crossing holes drilled diametrically therethrough, through which holes anchoring bolts 32 may be located between spaced ends of brush strips for purposes to be described later.

FIG. 6 shows a still further shaft and support assembly wherein stub shafts 36 are mounted in the yoke 24, the inner ends of the shafts 36 supporting anti-friction bearings 37, the outer races 38 of which directly support the brush shells 40. The races 38 provide spaced outer cylindrical surfaces on which the ends of the shells are clamped as hereinafter described. One outer race 38 may be provided with means, such as V-belt driven pulley 39, to drive the brush assembly 20.

(II) SEMI-CYLINDRICAL SHELLS Referring to all the figures and especially to FIGS. 4 and 5, there are shown the cast, molded or extruded semi-cylindrical brushing strip holding or anchoring shells 40 of this invention. Each of these shells has an internal cylindrical surface 41 which corresponds with the surface 27, of which shells 40 there are two for each brush assembly 20; each hollow semi-cylindrical shell 40 having raised integral pairs of converging ribs or fins 42 forming channels of dove-tailed cross section longitudinally along the outer surface thereof. The ends 43 of each shell may be plain, that is; the outer circumferential surface of the shell 40 may have its ribs removed for locating a band clamp as will be described later. The ribs 42 preferably are all of substantially uniform and of the same thickness throughout their lengths and also preferably are grouped in. pairs around the outer circumference of each shell 40 with the space between each pair of ribs 42 providing a seat or channel 44 for receiving the brush strips 50. As shown in FIGS. 2 and 16, the bases of the ribs may be close together to form double ribs of generally V-section, adjacent pairs of which produce channels 44 having side walls that converge toward their outer open ends. When brush assemblies of comparatively small diameter are required, the brush strip holding shells 40 may be formed with single ribs 42' as shown in FIGS. 3 and 12, wherein the outer ends of the ribs are spread laterally so that two adjacent ribs produce a channel 44 having converging outer ends. Each of the shells embraces an arc of approximately 180 between its parallel longitudinal edges 45, however, it is noted that this are should not be greater than 180 but is preferably slightly less, as shown in FIG. 11.

Because of the form of the shells 40 it is generally economically advantageous that these shells be fabricated by extruding a light-weight metal such as aluminum, however, any satisfactory material including plastic, moldable or extrudable, may be used.

When the shells 40 are fabricated by extrusion it is not possible for the plain ends 43 to be provided because of the fabrication process. In this situation the plain ends 43 may be provided merely by machining away the ribs 42 for the desired distance to provide the plain ends 43 of each element of the pair of shells 40.

Near the longitudinal edges 45 at and/ or intermediate of the ends 43 of each shell 40 between the pairs of ribs 42 there may be provided adjacently staggered apertures 46 (see FIG. 4) in the shells for the cross-tie bolts 32 as will be described later.

The shells 40 of FIG. 4 have straight edges 45 with the ribs 42 being straight longitudinally thereof along the axis of the extruded shell portions 40. In the preferred form of FIG. 5 the ribs 142 are still grouped into pairs but the shells are twisted between their ends 143 to provide a helical pattern both to the longitudinal edges and to the ribs 142 so that, when the brush strips 50 or are inserted between the ribs 142 of any given pair, a helical configuration is imparted to the brush strips. The maximum twist of each shell 140 is about one half revolution for assembly without removal of an end bearing to slip it over its cylindrical support drum or shaft.

(HI) BRUSHING STRIPS A plurality of linear brushing strips 50 are afiixed to the extruded shells 40. Each of these brushing strips 50 may comprise a U-shaped channel member 51 tightly holding the bristles 52, or folded felt strips 52' (FIG. 8) between the legs 54 thereof. The bristles 52, which may be of wire or a synthetic material such as nylon or rayon, or any other material such as fabric or felt strips 52 which may even be impregnated with abrasives, are folded into U-shaped elements and inserted or molded into the U-shaped channel 51. A wire 55 may be located at the bottom of the U of the bristles 52 or strips 52' within channels 51 to provide an expanded portion at the base of the bristles or strips over which the slides or legs 54 of the channels 51 may be crimped. This manner of providing a brushing element or strip is well known in the brush-making art and has long been used for providing linear brushing strips which may be held in a cylindrical brush assembly by means of the present invention.

The first stage of assembly of the brush units of this invention is to feed or slide in from the end the U- shaped brush element backing channel 51 of a brush strip 50 between the cooperating ribs 42 of a selected pair of ribs to seat against the outer circumference of the shell 40. While the converging walls of the channels 44 may, in some instances, serve to hold the brush strips 50 in position, the individual ribs 41 of the pair may be crimped at longitudinal intervals locally as at 57 (see FIG. 16) against the bristle backing strip 51 to securely lock the brushing elements 50 within the pair of ribs. As particularly shown in FIG. 16, these crimps in adjacent rib walls together form a further dovetail interlock to prevent both longitudinal and radial displacement of the brush strips in their channels 44. Further, as shown in FIGS. 2 and 16, the ends of the ribs 42 may be crimped at 58 to additionally lock the brush strips 50 in place. When the shells are twisted to provide a helical pattern to the ribs 41 and thus the bristles as shown in FIG. 6, there is no problem in inserting the strip brush elements 50 as these strips are flexible enough to allow easy manual manipulation for the proper insertion and seating between the ribs, particularly when the strips have been helically twisted prior to assembly.

(IV) SHELL CLAMPING MEANS Means have been provided for clamping both shell 40 against the outer cylindrical surface or surfaces 27 provided on the shaft member. Such means preferably take the form of shell clamping units 60 of the differential or variable circumferential band type and may be typified by the well known hose clamp. These clamps 60 may comprise a flexible metal strip 61 having a plurality of slots 62 (see FIG. 1) in one end portion with a housing 63 being affixed to the strip 61 at its other end. The housing 63 carries a worm gear 64 engageable with the slots in the first mentioned end of the strip 61. A screwdriver slot 65 or other means may be provided at one end of the worm for rotation thereof to vary the circumferential distance around the strip 61.

The brush strips 50 generally are affixed to the shells 40 by the brush manufacturer. However, the installation of the shells to the driven members or shafts 21 or 36 of the brushing machine'generally occurs at a different location, that is by the user, especially when the shells 40 of this invention are used as replacements for worn out brushes. At the location of the machine the pair of shells 40 or 140 are placed on the cylindrical mounting surfaces 27 or 38 of the shaft 21 or trunnions 36 comprising the driven member of the brushing machine (see FIGS. 1, 2 and 6). As the shells 40 or 140 are fitted to these cylindrical surfaces, it is preferable that there be a slight gap 70 (see FIGS. 2 and 7) between the longitudinal edges 45 or 145 of each of the shells 4% or 140. The circumferentially tightenable clamps 60 used with this invention are then engaged with the outer surfaces of the pair of shells at their plain unribbed ends 43 or 143.

Prior to tightening of the clamps 60 on shells 40 or 140, it is preferable that the housing 63 be located intermediate the longitudinal side edges 45 of one of the shells 40 or 140. The worm 64 is then rotated to engage the strip 60 in the slots thereof to reduce the circumference of the clamp 60 and to securely clamp and hold the shells 40 against the cylindrical surfaces 27 on the shaft 21 of the machine.

In order to assure that the shells 40 may not slip either longitudinally or .circumferentially upon shaft 21, the outer surfaces 27 of shaft and/or the inner surfaces 41 of the shells 40 may be roughened slightly, if desired, to provide increased frictional contact between the members, but not so much as to prevent tightening of the shells 40 around the surfaces 27 by flexing of the shells 40 to provide intimate non-slipping contact with the exterior mounting cylindrical surfaces 27 around their entire contacting circumferential surfaces. The gaps 70 are provided so that the shells 40 do not bind upon one another as they conform to the diameter of the surfaces 27 which assures that there will be maximum contact possible between the shells 40 and these surfaces 27.

As an alternate means for clamping the shells on the surfaces 27, crossed tie bolts 69 may be projected through aligned openings in the shells and shaft as shown in FIG. 3. Holes are provided in the corners of the shells as at 66 (see FIGS. 3 and 4) and the supporting cylinder and shaft may be diametrically drilled at 67 and 68, the holes 67 and 68 being spaced longitudinally adjacent each other to avoid interference between them.

It was mentioned previously that in the shaft 21 where the intermediate wheel 30 in FIG. 1 is used, there are diametrically drilled crossing adjacent holes 35 and also that the shells 40 may include apertures 46 which are diametrically opposed when the shells 40 are placed upon shaft 21. Holes 46 should be aligned with the hole 35 prior to tensioning of clamps 69. Similarly in FIGS. 6 and 10 there may be provided a ring between the ends of the shells 46 to which ring the shells may be clamped by the crossed bolts 32. Through bolts 32 having heads 81 and threaded ends 82 may then be engaged through the shell apertures 46 and the drum holes 35 or holes in ring 80 to be secured by nuts 83 on thethreaded ends 82 of bolts 32. Both the heads 81 and nuts preferably are of such size so as not to project above the outer edges of said ribs and the nut 83 only may be of a size and shape so as to be clamped against rotation between the pairs of ribs 42 between which it is located, as shown in FIGS. 7 and 9. These bolts 32 serve two purposes; first, they prevent the middle portion of the shells 40 between the ends 43 held by clamps 60 from expanding outwardly due to centrifugal force of the rotating brush assembly, and second, to provide an additional method by which the shells 40 are prevented from rotating or slipping on shaft 21. a When brush size permits, for example when radially long brushing elements or bristles 52 are used instead of the crossed bolts 32, a clamp 60 may be applied directly around the outside of ribs on the shells as shown in FIG. 10 and the ring 80 serves as an annular abutment against which the shells are clamped to prevent outward bowing of the shells during brush rotation. The bristles 52 or brushing parts 52 of the strips 59 may be trimmed away or spaced apart to provide room for the clamp 60 in FIG. 10, and also for the bolts 32 in FIG. 1 as shown.

From the foregoing description and discussion of the assembly of the shells 40 on the shaft or driven member 21 of the brushing machine it is evident that the brush shells 40 or of this invention provide a means whereby a worn out brush may be readily and rapidly replaced without removal of the shaft 21 from the machine. Because the brush shell elements 40 are mounted securely but removably on a rotatable mounting means, it is not necessary that the replacement brush carry its own shaft 21. This means that the operator of the brushing machine need maintain only a supply of the bristled or brushing extruded shells 40 corresponding to the diameter of the surfaces 27 or 38 provided on the shaft 21 or 36 of the brushing machine; this also reduces the weight of the replacement parts.

While there is described above the principles of this invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of this invention.

What is claimed is: v

1. The method of making brush members comprising extruding an elongated shell member of semi-cylindrical cross-section with a plurality of integral radially outwardly projecting longitudinally extending ribs, severing the extrusion into two shells of the same length, twisting a complementary pair of said shells between their ends to provide a helical pattern to the ribs, inserting brush strips between adjacent pairs of ribs, and deforming the ribs longitudinally therealong to anchor the brush strips to the shell.

2. The method according to claim 1 including removing said ribs from said shell a short distance inwardly from each severed end for the location of a band clamp around each end of each member.

3. A disposable cylindrical finishing brush assembly adapted to be mounted on a rotatable shaft having a continuous external cylindrical mounting surface at least at each end of said brush assembly, said brush assembly comprising:

(1) a pre-twisted complementary pair of elongated semi-cylindrical brush strip holding members provided with (a) a plurality of pairs of integral external radially projecting longitudinal extending ribs of uniform cross section throughout their entire lengths,

(b) said ribs near the end of said holding members being removed to provide an outer cylindrical continuous substantially semi-cylindrical surface,

(c) said pair of semi-cylindrical members each having a continuous semi-cylindrical inner surface of less than 180,

(d) said inner semi-cylindrical surface having a diameter substantially equal to the diameter of said continuous external cylindrical surface of said rotatable shaft on which said holding members are to be mounted,

(e) a plurality of elongated brushing element strips located between adjacent pairs of said ribs to provide a plurality of rows of radially extending brushing elements to provide an uninterrupted completely cylindrical brushing surface,

(f) deformable means along said ribs for anchoring said strips between said adjacent pairs of said ribs,

(g) said semi-cylindrical members being twisted not more than 180 between their ends, whereby their ribs extend slightly helically and said brush strips therein form a helical pattern; and

(2) circumferential removable strap means surrounding said outer continuous semi-cylindrical surfaces at said ends of said holding members for frictionally clamping said pair of holding members to said continuous external cylindrical surface of said shaft, whereby said strap means draw the adjacent edges of said holding members, which are spaced because they are less than in extent, together to prevent slipping between said members and said shaft.

4. A brush assembly according to claim 3 wherein said brushing element strips have U-shaped channel bases.

5. A brush assembly according to claim 4, including U-shaped bristles held around wires in and extending the length of said bases.

6. A brush assembly according to claim 4 including strips of foldable material secured in said U-shaped channel bases.

7. A brush assembly according to claim 6 wherein said pliable material is impregnated with an abrasive.

8. A brush assembly according to claim 3 wherein said strap means is of the hose clamp type.

9. A brush assembly according to claim 3 including means intermediate the ends of said holding members for preventing said holding members from deformation by centrifugal force during the rotation of said brush assembly.

References Cited in the file of this patent UNITED STATES PATENTS 417,566 Knowles et al. Dec. 17, 1889 1,439,159 Frost Dec. 19, 1922 1,637,996 Guttridge Aug. 2, 1927 2,285,375 Hansen June 2, 1942 2,583,336 Jones Jan. 22, 1952 2,597,421 White May 20, 1952 2,651,799 Lombardi Sept. 15, 1953 2,659,632 Enchelmaier Nov. 17, 1953 2,673,440 Sawyer et al Mar. 30, 1954 2,736,916 Lombardi Mar. 6, 1956 2,783,095 Ballard Feb. 26, 1957 2,921,329 Peterson Janv 19, 1960 2,970,333 Jones Feb. 7, 1961 2,978,726 Park Apr. 11, 1961 FOREIGN PATENTS 292 Great Britain Jan. 22, 1881 23,778 Great Britain Dec. 7, 1894 713,758 France Aug. 24, 1931

Claims (1)

1. 3. A DISPOSABLE CYLINDRICAL FINISHING BRUSH ASSEMBLY ADAPTED TO BE MOUNTED ON A ROTATABLE SHAFT HAVING A CONTINUOUS EXTERNAL CYLINDRICAL MOUNTING SURFACE AT LEAST AT EACH END OF SAID BRUSH ASSEMBLY, SAID BRUSH ASSEMBLY COMPRISING: (1) A PRE-TWISTED COMPLEMENTARY PAIR OF ELONGATED SEMI-CYLINDRICAL BRUSH STRIP HOLDING MEMBERS PROVIDED WITH (A) A PLURALITY OF PAIRS OF INTEGRAL EXTERNAL RADIALLY PROJECTING LONGITUDINAL EXTENDING RIBS OF UNIFORM CROSS SECTION THROUGHOUT THEIR ENTIRE LENGTHS, (B) SAID RIBS NEAR THE END OF SAID HOLDING MEMBERS BEING REMOVED TO PROVIDE AN OUTER CYLINDRICAL CONTINUOUS SUBSTANTIALLY SEMI-CYLINDRICAL SURFACE, (C) SAID PAIR OF SEMI-CYLINDRICAL MEMBERS EACH HAVING A CONTINUOUS SEMI-CYLINDRICAL INNER SURFACE OF LESS THAN 180*, (D) SAID INNER SEMI-CYLINDRICAL SURFACE HAVING A DIAMETER SUBSTANTIALLY EQUAL TO THE DIAMETER OF SAID CONTINUOUS EXTERNAL CYLINDRICAL SURFACE OF SAID ROTATABLE SHAFT ON WHICH SAID HOLDING MEMBERS ARE TO BE MOUNTED, (E) A PLURALITY OF ELONGATED BRUSHING ELEMENT STRIPS LOCATED BETWEEN ADJACENT PAIRS OF SAID RIBS TO PROVIDE A PLURALITY OF ROWS OF RADIALLY EXTENDING BRUSHING ELEMENTS TO PROVIDE AN UNINTERRUPTED COMPLETELY CYLINDRICAL BRUSHING SURFACE, (F) DEFORMABLE MEANS ALONG SAID RIBS FOR ANCHORING SAID STRIPS BETWEEN SAID ADJACENT PAIRS OF SAID RIBS, (G) SAID SEMI-CYLINDRICAL MEMBERS BEING TWISTED NOT MORE THAN 180* BETWEEN THEIR ENDS, WHEREBY THEIR RIBS EXTEND SLIGHTLY HELICALLY AND SAID BRUSH STRIPS THEREIN FORM A HELICAL PATTERN; AND (2) CIRCUMFERENTIAL REMOVABLE STRAP MEANS SURROUNDING SAID OUTER CONTINUOUS SEMI-CYLINDRICAL SURFACES AT SAID ENDS OF SAID HOLDING MEMBERS FOR FRICTIONALLY CLAMPING SAID PAIR OF HOLDING MEMBERS TO SAID CONTINUOUS EXTERNAL CYLINDRICAL SURFACE OF SAID SHAFT, WHEREBY SAID STRAP MEANS DRAW THE ADJACENT EDGES OF SAID HOLDING MEMBERS, WHICH ARE SPACED BECAUSE THEY ARE LESS THAN 180* IN EXTENT, TOGETHER TO PREVENT SLIPPING BETWEEN SAID MEMBERS AND SAID SHAFT.

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