US3107381A

US3107381A - Corrugated tube for rotary brushes

Info

Publication number: US3107381A
Application number: US824387A
Authority: US
Inventors: Ralph F Tilgner
Original assignee: Pittsburgh Plate Glass Co
Current assignee: PPG Industries Inc
Priority date: 1959-07-01
Filing date: 1959-07-01
Publication date: 1963-10-22
Anticipated expiration: 1980-10-22

Description

Oct. 22", 1963 R. F. TILGNER 3,107,381

CORRUGATED TUBE FOR ROTARY BRUSHES Filed July 1, 1959 3 Sheets-Sheet 1 FICA F'|G.5

A3 Efi ,7 A r. V 49 Bio. a 49G 48 f? 5 4 R U 4m INVENTOR. RALPH A mam-.2

Oct. 22, 17963 R. F. TILGNER 3,107,381

CORRUGATED TUBE FOR ROTARY BRUSHES 5 Sheets-Sheet 2 Filed July 1, 1959 I58 INVENTOR.

Oct. 22, 1963 R. F. TILGNER CORRUGATED TUBE FOR ROTARY BRUSHES 5 Sheets-Sheet 3 Filed July 1, 1959 'FIO.I6

FIG. I3

FIGS

\ INVENTOR.

\ 24.41% A mom-a United States Patent 3,107,381 (IORRUGATED TUBE FQR RQTARY BRUSHES Ralph F. Tilgner, Ellicott (Iity, Md, assignor to Pittsburgh Plate Glass Company, County of Allegheny, Pan, a corporation of Pennsylvania Filed July ll, 195$, Ser- No. 324,387 13 Claims. (Ql. -182) This invention relates to power-driven brushes and it has particular relation to mandrel structures for such brushes and to novel means for securing the several elements of the brush structure together.

Power-driven brushes have heretofore been formed by spirally winding upon a tubular cylindrical core or mandrel, a brush strip comprising a channel backing element having doubled fill material secured therein by means of a longitudinally extending filamentary locking core. Such brushes are relatively inexpensive to construct, but are characterized by certain disadvantages, especially if operated under heavy loads and/ or at high speeds. For example, the mandrels are often either excessively heavy, cumbersome and expensive to form, or else they are lacking in rigidity against bending forces. Furthermore, the fill material and the channel backing may tend strongly to overheat due to frictional effect and/ or rapid flexing of the fill material. Such overheating is often detrimental to the fill material and/ or the core or mandrel upon which the strip is mounted.

High speed operation of the brush also generates strong centrifugal forces, tending to distort the mandrel and to throw the brush strip or the components thereof away from the mandrel. Such centrifugal force may be so great as to cause detachment of the strip, in which instance it unwinds and may endanger personnel or equipment in the vicinity. This invention comprises means for obviating the foregoing problem. Several features are involved and these often can be employed concurrently in a single structure or can be employed individually in certain other combinations. 7

One feature of the invention comprises the provision of a mandrel for a spirally wound brush strip, which mandrel is formed of a tube of sheet metal, e.'g., steel, having a series of peripherally spaced corrugations running longitudinally thereof. Such corrugations greatly enhance the stiffness of the mandrel to resist flexing movements exerted transversely of the axis of the brush and do not add greatly to the weight of the construction.

As a second feature, the brush mandrel involves a novel bushing structure comprising discs having teeth or tabs adapted to project into the corrugations of the mandrel, whereby to provide a very strong driving connection between the bushing and the mandrel.

As a third feature, the invention comprises the provision of a novel method of securing the mandrel shell to the adapter involving screws, preferably of the selfthreading type, adapted to be inserted through the mandrel shell and correspondingly through coaxially extending flanges upon the adapter.

A fourth feature comprises the provision of a novel system of U-like clamp elements, one or both legs of which are adapted to extend through appropriate slots formed in the corrugations of the mandrel to embrace the brush strip wound upon the mandrel and having elements such as screws or bolts, extending through its sides and engaging the side walls of the channel backing element of the brush strip to hold the same in position.

Sixthly, the invention comprises the provision of novel strap elements for attaching intermediate turns of the brush strip element to the mandrel.

These and other features of the invention will be ap- A 3,lt?,38l Patented Oct. 22, 1963 parent from consideration of the drawings and the descriptions thereof to follow.

lnthe drawings,

FIG. 1 is an isometric view of a presently preferred form of a mandrel structure embodying the invention.

FIG. 2 is a plan view of a bushing adapted to be inserted in the mandrel shell disclosed in FIG. 1.

FIG. 3 is a sectional view substantially upon the line III-III of FIG. 2. 1

FIG. 4 is a fragmentary detailed view of a clip element securing a brush strip to a mandrel.

FIG. 5 is a second fragmentary detailed view of a form of clip which is of sufiicient width to grip two turns of the brush strip, whereby to form loops in the strip which are positively held from untwisting or loosening upon the mandrel.

FIG. 6 is a fragmentary sectional view through one of the clips, showing the manner in which the shelf-threading screw therein bites into the edges of the channel member of the brush strip to lock same from movement in the clip.

FIG. 7 is a fragmentary sectional view of a clip structure useful in securing the intermediate turns of a brush strip to the mandrel.

FIG. 8 is a sectional view of one form of the mandrel structure, showing the winding and the securing of the brush strip thereupon by welding.

FIG. 9 illustrates a modified form of sheet metal blank having corrugations formed therein, but being uncircularized and being adapted for use in forming a shell of the mandrel structure shown in FIG. 8.

FIG. 10 is a sectional view substantially upon the line X--X of FIG. 9'.

FIG. 11 is a plan view of a further modification of a corrugated sheet suitable for use in forming the shells of rn'andrels.

FIG. 12 is a sectional view substantially upon the line XlIXlI of FIG. 11.

FIG. 13 is a view partly elevation and partly in phantom of a brush constructed in accordance with the provisions of the invention.

FIG. 14 is a sectional view showing a suitable fixture and the use thereof in assembling a brush in accordance with the provisions of this invention.

FIG. 15 is a fragmentary sectional view showing a portion of a rotary chuck suitable for use in winding a brush strip upon a mandrel constructed in accordance with the provisions of this invention.

FIG. 16 is a sectional view substantially upon the line XVIXVI of FIG. 13.

In the preferred embodiment of the invention as disclosed in FIG. 1, a mandrel for a spirally wound brush is illustrated as comprising a shell or tube 20 formed of sheet metal with flutings or corrugations formed by ridge or land portions 21 running longitudinally thereof. In the drawing, the number of land portions is indicated as being nine, but any other convenient number obviously could be employed. The land portions are connected together by intermediate depressed web portions 22, which are indicated as being connected to the side wall portions 23 of the land portions 21. The web portions are also indicated asbeing angularly 'bent along lines 24 at their mid-portions, thus providing secondary corrugations of approximately V-shape section-s. The shell or tube therefore may be considered as being of polygonal section wherein curved portions are obviated.

,Any convenient method may be employed in forming the various bends or angles the shell. For example, a blank of sheet metal such as iron or steel may be passed between rollers having properly sectioned fiutings thereupon. Also, the blanks of sheet metal may be subjected to a pressing operation in a press having properly configured platens to form single units of the mandrel surface in a series of steps. Since the face of the sheet is formed of a series of flat, longitudinally extending strips integrally joined along the several angles of the structure, the latter method is suited for small scale operations where it is not convenient to make up expensive special rollers or dies designed to shape the entire blank in a single step. This method is slower than the first method and involves more labor. However, the necessity of providing configured rollers or dies having repeating units of surface is obviated and a conventional metal bending press can then be used.

It is convenient in forming the several longitudinal bends in the sheet metal blanks to effect the bends at such angles that the sums of the several bends will cause the metal to assume naturally an approximate cylindrical section so that when the bushings to be described are inserted therein, only slight bending will be necessary to attain the final shape. If desired, the angles or bends between the portions 23 and the webs 22 may be approximately right-angular. The sums of the angles 24 in the web portion will then provide the necessary bending of the metal approximately to obtain the desired perimeter of the shell.

Appropriate bushings for the shells are indicated at 26. These may be formed as annular members having internal and

external flanges

27 and 28 extending coaxially of the mandrel. The outer flange 28 may be slotted at one or more points around its perimeter, as indicated at 29, and the resultant tabs of sheet metal integral with the rear edge notch formed by slots 29 are bent radially outwardly as indicated at 31, providing teeth or keys spaced to seat within corrugations 21 in order to secure the bushing from rotation within the shell 20. Obviously, teeth might be provided for each land around the circumference of the shell, though in the drawings, a pair of teeth are shown and these are disposed in contiguous lands or cor rugations.

It will be apparent from the drawings and notably from FIGURE 2, that the teeth substantially correspond in dimensions to the transverse sectional dimensions of the corrugations.

This construction has advantages in assembly, inasmuch as the spacing between contiguous lands 21 will vary but slightly and, therefore, a good fit between the lands and the teeth can readily be obtained without the necessity of springing the metal forming the sheet. In event that there should be slight variations in the dimensions of the lands, the accumulation of errors around the perimeter is obviated. Good fit between the shell and the bushings is thus obtained at all times. Winding of the corrugated sheet forming the shell about the bushing is also facilitated.

It will be observed that a portion of the side wall and the inner flange of the bushing in the shell may also be cut out as indicated at 32, to provide a key-way in which a key may be inserted, providing means for supporting and driving the mandrel upon a shaft or arbor.

Substantially any number of bushings may be provided in the shell and such number will depend upon the length of the mandrel, the gauge of the metal employed and the stresses to which the mandrel is likely to be subjected in service. In many instances, a pair of bushings will be sufficient. These may be disposed at the ends of the shell, or may be spaced inwardly therefrom. In event that conditions require the same, one or more intermediate bushings, such as the one indicated at 33 in FIG. 1, may be employed.

The end portions of the metal forming the shell are indicated as overlapping as at 34. The shell may be held in assembled relationship upon the flanges of the bushing elements by appropriate means as, for example, by one or more straps 36 of sheet metal, such as sheet steel. As many such straps as may be desired may be employed, though in FIG. 1 the number is limited to one. These straps are of the conventional type employed as ties in holding bales or bundles together. The ends 37 of the straps overlap in conventional manner and are held together as by simple seal elements 38, which may be clipped or crimped in well-known manner as indicated at 39, in order securely to hold the straps in place.

These straps (sold as Signed steel strapping) and the seals therefor may be employed as the binding for the mandrels. These materials are commercial products which can be obtained at small expense. Also, the conventional stretcher and sealer units required for tightening the straps and for applying the seals to hold the ends of the straps from movement, may be used with little or no modification. Needless to say, other types of strapping and seals, and other apparatus for stretching the straps and applying the seals may be employed.

The straps, if desired, may be permanently retained and when so employed, they add substantially to the strength of the structure and thus constitute safety features. The relative thinness of the straps permits the brush strip material to be spirally wound upon the mandrel with out appreciable distortion from the general section of the brush when the strip crosses or is superposed upon the strapping.

It is also permissible, if so desired, to remove the straps from the shell 23 after the other fastenings to he described have been disposed in place.

Various means to secure the overlapped end portions of the shell 2%} may be employed. For example, the ends may be secured together by spot welding. It is also permissible to secure said portions together by rivets, by bolts, by nails or by screws. Self-threading screws of wellknown type are to be preferred because of economy and ease of insertion. Such screws are indicated at 41'. These screws, if desired, may also penetrate the flanges 28 of the bushing elements, whereby to secure the ends of the blanks forming the shell to the bushing. Screws may be employed to secure the ends of the blank to each bushing. If desired, additional screws may also be employed securing the ends of the blanks together intermediate of the bushings.

The strapping about the shell, together with the teeth 31 upon the bushing, may be relied upon as the sole securing means holding the shells in assembled relation upon the bushing and maintaining the shell from slippage upon the mandrel. However, it is often preferred to employ additional screws around the perimeter of the shell, penetrating the shell as at '42, intermediate of the lands 21 and penetrating the flanges 28, thus securing all of the bushings rigidly in place.

A conventional brush strip suitable for winding upon the shell is indicated at 43. This strip comprises a channel backing 44 having doubled fill material 46 such as fibers of Tampico, nylon or the like, disposed therein and being held in place by a filamentary core 47 disposed in the bight portion of the fill. This brush strip is spirally wound upon the mandrel in well-known manner. However, in the winding operation, an advantage results from the corrugation or fluting of the shell element of the mandrel, inasmuch as the backing element of the strip in spanning between the lands 21 is caused to bend, forming slight angles at the corners of the lands. As a result, the turns of strip as they are wound upon the mandrel, assume the form of a polygon. This does not appreciably affect the brushing characteristics of the assembled brush, but is of advantage inasmuch as it reduces the tendency of the brush to rotate or slip upon the mandrel and tends to reduce the stresses which are placed upon the clip elements or other fastening devices employed in securing the backings of the brush strip upon the mandrel.

If desired, the end turns as well as the intermediate turns of the backing may be secured to the mandrel by spot welding between the metal of the backing and the shell of the mandrel at certain of or all of the crests of the corrugations. It is also permissible to use the type of Welding to be described in connection with subsequent FIG. 8.

A preferred type of securing means as illustrated in FIGS. 1, 4 and 5, comprises U-shaped clips 43 of flattened section which may be single as at 43 in FIG. 4 or of double width as shown at 4312 in FIG. 5 to secure together portions of the strip to provide a complete loop upon the mandrel. Each clip has a leg 48a connected to an intermediate or bight portion and which is adapted to be inserted through appropriate slots or

openings

49 or 49a in the metal of the shell of the mandrel in the land portion 21. As illustrated in the drawing, a single slot is employed for each clip, one leg of the clip extending through this opening and the other being disposed outside of the end of the shell. If preferred, however, two longitudinally spaced slots or openings may be provided for each clip and both legs of the clips may then be inserted through these openings.

In event that the bands 36 are to be retained as permanent portions of the mandrel, it is not precluded to form longitudinally extending slots as at 36a therein for the reception of the legs of clips. When a turn of a brush strip crosses the bands at or near these slots, clips may be inserted through the slots to assist in holding the turns in place. To admit of accurate position of the clips, to receive the turns, the slots may be of a considerably greater length than the width of the sides of the clips so that a clip can be peripherally moved to a point where the spiral of the strip will accurately fall between the branches of the clip. Both legs of a clip may be inserted in a pair of slots. It is also not precluded to insert one leg of a clip in a slot and to allow the other leg to project outwardly beside the band. This gives further flexibility in positioning the clips to receive the turns of the brush strip. If desired, a pair of clips can then be accommodated in each slot. As many slots as may be desired may be formed in a iband.

In FIG. 1, three clips are indicated as being equally spaced about the perimeter of the mandrel at the end thereof. Obviously, any other appropriate number of clips might be employed. For example, if the service required of the brush is not too heavy, the number of clips may be reduced to two or even to one. On the other hand, if very heavy services are required of the brush, the number may be increased as desired. 'In the drawings, the clips are indicated only at the ends of the mandrel. In these positions, they effectively hold the ends of the strip. Usually, this is sufiicient and clips engaging the intermediate portion of the brush are not required, but their use is not precluded. They may be applied at any point along the length of the strip by appropriately slotting the metal of the lands 21 to receive the legs of the clips.

Means to hold the sides of the strip in firm engagement with the side wall of the channel backing element of the strip are indicated as comprising screws such as are shown at 5 1 or 51a in FIGS. 4, 5 and 6 of the drawings. These screws may be of the conventional selftihreading type designed to form their own threads by biting into the metal penetrated by them. As shown in FIGS. 5 and 7, nuts of the so-called Tinnerman type comprising U-shaped pieces of metal 52 providing self-threading nuts, may also be disposed over one of the legs of the clips and these may be employed to hold the screws in place. In the latter event, holes for the reception of the screws may be punched or bored in both legs of the clips of a size to permit the screw threads to pass without biting into the metal.

In FIG. 7 is illustrated a detailed view of a modified form of clip adapted (for securing at intervals along the length of a brush strip in order more securely to hold the intermediate turns in place upon a mandrel. In this construction, the shell portion of a mandrel is indicated as at 69 and includes longitudinally extending corrugations 61 corresponding to the corrugations 2.1. These corrugations, of course, are separated by intermediate webs (not shown). The blanks from which the shell of the mandrel is formed may be provided with slots 62 distributed along the entire length of the blank. The number of slots so provided may be substantially greater than are required for the reception of the clips for holding the brush strip in place. This is true because the thickness of a brush strip tends to vary to a certaian degree and, therefore, it is difiicult to provide slots which are in all instances precisely spaced to register with the turns. By increasing the population of slots, the probability of enough turns of the strip coming into register with a sufl'icient number of slots is increased.

In order further to accommodate for the variation in the spacing of the turns with respect to the slots and also to permit securing U-shaped clips to intermediate turns of the brush strip while operating entirely from the exterior of the mandrel shell, as shown in FIG. 7, appropriate clip holders 63 may be provided.

These holders are mere strips of metal, each having a hooked portion 64 adapted to be inserted into an opening 62. The projecting portion of the strip is bent over upon the top of the corrugation 61 corresponding to a corrugation or land 21, and a turn 65 of the brush strip is wound thereupon to hold the strip in place. A clip 66 of greater width than strip 63 and having slots as at 67 in the sides near the bottom thereof is provided, and the end of the strip is inserted through the slots. A turn 68 of the brush strip is then wound between the branches of the clip and is secured by transverse screw 69 and Tinnerman nut 69a. Insertion of the screw causes the bottom of the brush strip channel to be pressed against strip holder 63 to grip the latter. The end of the clip holder strip is allowed to project from the side of the clip and is held down by one or more subsequent turns 68a of the brush strip.

If desired, the clip holder strip 63 may be formed to a length to extend under several turns of the brush strip, thus increasing the security with which the strip is held. The strip 63 may even extend the length ofthe mandrel shell and a number of clips 66 may be strung thereupon. A clip may be provided for each turn or they may be provided only for certain turns, for example, for each third or fourth turn. The ends of the strip 63 may be held as shown in slots 62 or, if preferred, they may be spot welded to the mandrel shell or they may be held by screws extending through the ends of the strip and the shell. If strips 63 are long, the intermediate portions thereof may also be secured at intervals to the shell by spot welding or by self-threading screws. A turn of the brush strip can then be taken over the top of the weld or screw. Clip holder strips 63 may be spaced at intervals around the mandrel, for example, at or 120 angles, to obtain balance.

It is an advantage of the clip holder strips that clips thereupon can be slid longitudinally as the brush is wound to accommodate for irregularities of the thickness of or spacing of the 'brush strip turns.

The foregoing system can be used to secure intermediate turns of the strip, but the end turns of the strip can still be secured as by the clip arrangements illustrated in FIGS. 1, 4, 5, 6 and 7.

In FIG. 8 of the drawing is shown the formation of a slightly modified form of brush structure embodying the main principles of the invention. In this construction, spot welding as at W is employed to secure the shell of the mandrel upon the bushings thereof. Also, the backing element of the 'brush strip is secured at appropriate points along its length with suitable spots of weld metal applied to the backing and to the tops of the corrugation of the shell of the mandrel in order to effect union between the two. In this construction, the corrugated shell has bushings I01 disposed therein. The bushings are provided with perimetric

cylindrical flanges

102 and 103, the latter of which (the outer) is slotted at proper intervals and has portions bent radially outwardly to provide teeth or lugs 134 engaging in the corrugations in order to provide a positive drive between the bushing and the mandrel shell. A key-way 166 is also formed within the inner perimeters of the bushings in order to receive a key locking the bushings from rotation upon a shaft 167.

A brush strip 198, having fill material 199 secured in a channel backing element 110 by a core 112 of wire or other material, is secured at one end to an end of a corrugation of the mandrel shell. Means to effect securement of the end turns may comprise U-shaped clips such as have already been described in connection with FIGS. 1, 4, and 6. Welding such as is to be described, or other menas may also be employed. The precise method of securing the end turns of the brush strip is not shown in the figure.

After the end of the brush strip has been secured, the shaft 197 is rotated to wind the brush strip as a spiral upon the mandrel. At all of, or certain of, the points where the strip crosses the corrugations of the mandrel, the channel backing element may be secured to the crest of the corrugations as by electrical welding. Welding may conveniently be performed by means of spaced electrodes 113 having conductors 114 joining them to an appropriate source of electrical current. Metal for the weld between the crests of the corrugations and the channel backing element of the brush strip is applied by a welding rod 115, the tip of which is disposed in or near the are between the tips of the electrodes, whereby to fuse bits of the metal of the rod as gobs or nodules 117, which by union with the metal of the shell of the mandrel and the channel backing element, provide a bond between the two. As many points of welding as may be desired may be pro vided in order to effectively secure the brush strip to the mandrel. When the winding and welding operation is completed, the brush strip may be severed from the portion remaining unwound. The end of the spirally wound portion of the brush strip may then be secured to the mandrel to complete the brush.

In FIGS. 9, 10, 11 and 12, are illustrated several dilferent blanks or sheets of metal which have been provided with appropriate corrugations, adapting them to be bent and secured upon suitable bushings to provide mandrels, also embodying the principles of the present invention. As illustrated in the several FIGURES, 9-12, the sheets of metal constituting the starting blanks are appropriately stamped or rolled to provide the corrugations while retaining the overall flatness of the sheets. The formation of corrugated units in this manner may be performed in a factory performing the metal rolling, and the flat units can be stacked in small space for shipment to the brush manufacturer, who will then circularize the units and assemble them upon bushings to provide brush mandrels in the manner already described.

In the construction illustrated in FIGS. 9 and 10, the fiat sheet is rolled or otherwise bent to provide a series of spaced, transverse corrugations 121 having angular corners and being separated by intervening valleys or reverse corrugations 122.

In this construction, the circulation of cooling air through the finished mandrel may be promoted by the formation of openings 124, either in the corrugations or in the valleys between the corrugations. When the brush is rotated, these openings permit the air impelled by centrifugal force of rotation to pass outwardly, thus producing a cooling action about the channel elements of the brush strip.

In the construction as illustrated in FIGS. 11 and 12, the intermediate portions of a blank 130 are provided with corrugations 131. These corrugations, as shown in FIG. 12, are of semi-circular or other appropriate section and may be formed in the metal by a stamping or rolling operation. Marginal bands or strips 133 of the blank are left plain and these marginal portions possess the advantage that they do not stretch or become distorted when the blank is circularized and applied to the bushing elements. The marginal portions provide convenient zones for the insertion of self-threading screws or other fastenings, such as bolts or rivets, securing the mandrel shell to the flanges of the bushings. To this end, the blanks at the time the corrugations are formed may also be provided with holes 134 punched to receive such screws, and matching holes may be formed in the perimetric flanges of the bushings.

It is an advantage of this construction that the spacing between the holes cannot be altered by the bending operation involved in circularizing the mandrel.

The shells from blanks can be circularized and held upon the bushings with or without the use of straps such as the straps 36. The overlapped ends of the blanks 129 or 130 after circularization of the latter, can be held together by welding, brazing, self-threading screws, rivets, bolts, or by other devices.

FIG. 14 illustrates a suitable fixture for holding the bushings of a mandrel in proper position while the shell is being secured thereupon.

In this construction, a shaft is formed with pairs of appropriately spaced detents 141 mounted in radial holes 142 and being resiliently outwardly urged by coiled springs 143. The distance between the detents of a pair is such that they will engage and grip the edges of the inner perimeter of a bushing to hold the same, but will yield to permit the bushings to be slid into place or removed from the shaft at will. But single pairs of detents for each bushing have been illustrated. However, added pairs of detents circularly spaced from these may also be provided in order to assure that the bushings will be held in a plane vertical to the shaft 149.

Bearings or supports for the shaft are not shown, but may be conventional bearings or spaced brackets, clamps, or other devices designed to hold the shaft by one or both ends while the bushings are mounted and the shell is secured thereupon.

To form a mandrel upon this fixture, bushings are spaced upon the shaft and held by detents 141. The shell of the mandrel is then placed upon the bushings and is held by bands as at 36. Such screws or other fastenings as are required may also be inserted at this stage.

When the mandrel is assembled, it may be removed and secured in a lathe for winding the brush strip thereupon. An appropriate chuck structure for such lathe is illustrated in FIG. 15, as comprising a shaft 15% mounted in bearings (not shown) and being power driven by a motor drive (also not shown). Upon the shaft is disposed a disc-like face plate 152 having a coaxially disposed rim 153 with a shoulder 154 providing a stop for a mandrel shell 20. Lugs 155 are provided upon the rim to project into the corrugations of the shell to provide a positive drive for the mandrel as the winding of the strip is conducted.

Preferably, two of these chucks, one for each end of the mandrel, are provided and they are carried upon separate coaxially spaced shafts to permit the mounting or removal of the mandrels as required.

The shaft should be splined as at 156 to permit the face plate to be retracted from the end mandrel, but providing a positive drive between the shaft and the face plate. Means to hold the face plate in position upon the shaft is illustrated as comprising a set screw 157 threaded through a hub portion 153 of the plate. Obviously, other means releasably to hold the face plate from retraction from the mandrel may be employed.

When a brush strip is being wound upon this structure, the ends of the mandrel are clamped by the face plates, with lugs inserted in the ends of one or more corrugations. An end of a brush strip is secured at an end turn in the manner already described and the mandrel is slowly rotated spirally to wind up the strip. If desired, additional fastenings between the strip and the shell of the mandrel are applied as the strip is wound. When in the winding operation the last turn is reached, the end clips or other fastenings are applied to the brush strip and the latter is out (if an excess is present), thus conipleting the brush. One of the face plates may then be released by unscrewing set screw 157 and the plates can be separated to permit the completed brush to be removed and a new mandrel can be inserted for winding.

A complete brush B is illustrated in FIGS. 13 and 16, and is keyed as at K upon a mandrel M.

I claim:

1. A rotary, power-driven brush comprising a mandrel, which is a sheet of metal constituting a tube, bushings disposed within the tube, said tube further having slots formed therein and U-shaped clips having bight portions disposed within the tube and legs radially outwardly extending through the slots, the clips being of flattened section, and a brush strip comprising a channel backing wound about the mandrel, the clips engaging the turns of the brush strip and means securing the strip in the clips, said means comprising screws extending through 1e sides of each of the clips and engaging the side walls of the channel backing of the strip.

2. A rotary, power-driven brush comprising a mandrel, which is a longitudinally corrugated tube and having spirally wound thereupon a brush strip comprising a channel backing element and fill material disposed in said channel backing element, and means securing the brush strip to the mandrel comprising flat metal strips secured to the mandrel and extending longitudinally thereof, and U-shaped clips having slots formed in the sides thereof, the fiat metal strips extending through the slots, said U-shaped clips engaging the side walls of channel backing element to secure the same to the mandrel.

3. A rotary, power-driven brush comprising a mandrel, which is a longitudinally corrugated tube of sheet metal, the tube being provided with bushings having teeth elements engaging the corrugations of the tube to provide a positive drive between the bushings and the tube, a band comprising a strip of metal disposed about the tube to hold the same upon the bushings, a brush strip comprising a channel backing with fill material disposed the-rein, spirally wound about the tube, the backing of said strip having substantially straight portions across the depressions formed by the corrugations to impart to the turns ott the strip the form of a polygon, whereby to prevent rotation of the strip upon the tube under heavy loads.

4. A rotary, power-driven brush comprising a mandrel, which is a longitudinally corrugated tube having spirally wound thereupon a brush strip comprising a channel backing element and fill material disposed in said element, said element being secured at each end to thetube and the intermediate portions of the elements, where they cross the depressions formed by the corrugations of the tube, being substantially straight to impart to the turns of the strip a polygonal shape, whereby the strip is held from rotation with respect to the tube when the brush is performing work.

5. A rotary, power-driven brush comprising a mandrel, which is a longitudinally corrugated tube having spirally wound thereupon a brush strip comprising a channel backing element and fill material disposed in said element, said element being secured at each end to the tube and the intermediate portions of the elements, where they cross the depressions formed by the corrugations of the tube, being substantially straight to impart to the turns of the strip a polygonal shape, whereby the strip is held from rotation with respect to the tube when the brush is performing work, means to secure the strip to the tube comprising U-shaped clips having branches extending through slots formed in the corrugations of the tube and embracing the sides of the strip, and screws extending through the sides of the clips and engaging 10 the edges oil the channel backing element to lock the latter in place.

6. A rotary, power-driven brush comprising a mandrel which is a sheet metal, longitudinally corrugated tube, said tube having bushings disposed therein, said bushings having teeth spaced about the outer perimeters thereof and spaced segments of a coaxially extending flange, a segment being disposed between pairs of teeth, said teeth being disposed in the corrugations of said tube to provide a positive drive between the bushings and the tube, screws extending through the walls of the tube and the segments of the flanges upon the bushing-s to secure the bushings in place in the tube, a brush strip having a channel backing with fill material disposed therein, said st-rip being wrapped about the tube, and U-shaped clip elements having intermediate bight portions disposed within the tube and having legs extending through slots formed in the tube and engaging the turns of the strip element to hold the latter in place upon the tube.

7. A rotary, power-driven brush comprising a mandrel which is a longitudinally corrugated tubeof sheet metal, wherein the sides of the corrugations are substantially spaced, the sheet having overlapped ends secured together and providing a longitudinal scam in the tube, and having a spiral brush strip thereupon, said strip comprising a channel backing element secured to the crests of at least some of the corrugations, spaced annular bushings disposed in the tube, a pair of radially projecting teeth disposed at the outer perimeter of each of said bushings and projecting into a pair of contiguous corrugations of the tube, the remainder of the perimeter of the bushings being free of teeth, teach tooth being of dimensions substantially corresponding to the sect-ion of the corrugation into which it projects, said bushings having longitudinally extending, peripheral, outer flange portions between the teeth, and means securing the portions of the tube between the corrugations to the flange portions.

8. A rotary, power-driven brush comprising a mandrel which is a longitudinally corrugated tube of sheet metal, wherein the sides of the corrugations are substantially spaced, the sheet having overlapped ends secured together by means of screws extending through the overlapped portions and providing a longitudinal seam in the tube, and having a spiral brush strip thereupon, said strip comprising a channel backing element secured to the crests of at least some of the corrugations, spaced annular bushings disposed in the tube, a pair of radially projecting teeth disposed at the outer perimeter of each of said bushings and projecting into a pair of contiguous corrugations of the tube, the remainder of the perimeter of the bushings being free of teeth, each tooth being otf dimensions substantially corresponding to the section of the corrugation into which it projects, said bushing-s having longitudinally extending, peripheral, outer flange portions between the teeth, and screws extending through the portions of the tube between the corrugations and the flange portions whereby to secure the tube to the bushings.

9. A rotary, power-driven brush comprising a mandrel which is a longitudinally corrugated tube of sheet metal, the sides of the corrugations being substantially spaced, the tube having a spiral brush strip thereupon, said strip comprising a channel backing element and fill material disposed in said element, said element being secured to the crests of at least some of the corrugations, and spaced annular bushings disposed in the tube, said bushings having radially projecting teeth disposed at the outer perimeter thereof, the teeth being peripherally spaced about the bushings to project into a plurality of corrugations of the tube, and each of said teeth being of dimensions substantially corresponding to the section of the corrugation in which it projects, and a band comprising a strip of metal disposed about the tube and having the ends thereof secured together to hold the tube from expansion from the bushings, the brush strip further being 11 wound over said band, longitudinally extending flange portions at the outer perimeter of each bushing and being disposed between said teeth, and screws extending through the portions of the tube between the corrugations and through the flange portions and securing them together.

10. A rotary, power-driven brush comprising a mandrel which is a sheet of metal longitudinally corrugated and providing a tube, the sides of the corrugations being substantially spaced with respect to each other, said mandrel having bushings disposed therein, each of said bushings having a plurality of radially outwardly projecting teeth of dimensions substantially corresponding to the cross-section of the corrugations, the peripheral spacings of the teeth also corresponding to the spacing of the corrugations, and each bushing further having coaxially extending outer peripheral flange portions disposed between the teeth, screws extending through the walls of the tube and the flange portions upon the bushings to secure the bushings in place in the tube, a brush strip having a channel backing and till material disposed therein wrapped about the tube, and U-shaped clip elements having legs extending through slots formed in the tube and engaging turns of the strip to hold the latter in place upon the tube, the bignt portions of the clips being disposed within the tube.

11. A rotary, power-driven brush comprising a mandrel which is a longitudinally corrugated tube of sheet metal, the sides of the corrugations being substantially spaced, the tube having a longitudinal seam therein and having spirally wound thereupon a brush strip comprising a channel backing element and fill material disposed in said element, said element being secured to the crests of at least some of the corrugations, and spaced annular bushings disposed in the tube, each of said bushings having radially projecting teeth disposed at the outer perimeter of the corrugations of the tube and each of the teeth being of dimensions substantially corresponding to the section of the corrugation in which it projects, and a band comprising a strip of metal disposed about the tube to hold the tube upon the bushings, the brush strip further being wound over said band and longitudinally extending flange portions at the outer perimeter of each bushing, and being disposed upon each side of each of said teeth, and screws threaded through the walls and the flange portions to hold the bushings in place.

12. A rotary, power-driven brush comprising a mandrel, which is a sheet of metal constituting a tube, bushings disposed within the tube, said tube further having slots formed therein and U-shaped clips having the bight portions thereof disposed within the tube and legs radially 12 outwardly extending through the slots, the clips being of flattened section, and a brush strip comprising a channel backing wound about the mandrel, the clips engaging the turns of the brush strip, and screws extending transversely of the brush strip through both legs of each of the clips and drawing the legs together, thus clamping the brush strip in the clips.

13. A rotary, power-driven brush comprising: (1) a single flexible sheet of metal in the form of a tube, the ends of the sheet being overlapped and means securing the overlapped ends of the sheet together, said sheet having peripherally spaced, parallel corrugations and inwardly projecting web portions therebetween,

(H) a plurality of annular sheet metal bushings disposed in longitudinally spaced relationship within the tube,

(111) said bushings each having a peripheral flange extending coaxially of the tube and engaging said web portions whereby to support the tube in place upon a mandrel, the flange being secured to the bot toms of the web portions,

(IV) the flange upon a bushing having a notch in an edge thereof and a tooth integral with the bottom of the notch and projecting outwardly in the space Within a corrugation in the tube, and providing a positive drive between the tube and the bushing, said tooth being of dimensions corresponding to the cross-sectional dimensions of said corrugation, and

(V) a brush strip having fill material projecting outwardly therefrom, the strip being wound around the tube and being secured thereto.

References Cited in the file of this patent UNITED STATES PATENTS 181,524 Dickinson Aug. 29, 1876 612,157 Cook Oct. 11, 1898 642,484 Phillips Jan. 30, 1900 1,479,074 McLaughlin Nov. 20, 1923 1,579,182 Thayer Mar. 30, 1926 2,285,375 Hansen June 2, 1942 2,379,205 Wesemeyer June 26, 1945 2,651,799 Lombardi Sept. 15, 1953 2,757,401 Peterson Aug. 7, 1956 2,824,327 Van Clief Feb. 25, 1958 2,882,815 Bernier Apr. 21, 1959 2,907,063 Jones Oct. 6, 1959 2,921,328 Bongiovanni Jan. 19, 1960 2,977,622 Nelson et a1. Apr. 4, 1961

Claims

1. A ROTARY, POWER-DRIVEN BRUSH COMPRISING A MANDREL, WHICH IS A SHEET OF METAL CONSTITUTING A TUBE, BUSHINGS DISPOSED WITHIN THE TUBE, SAID TUBE FURTHER HAVING SLOTS FORMED THEREIN AND U-SHAPED CLIPS HAVING BIGHT PORTIONS DISPOSED WITHIN THE TUBE AND LEGS RADIALLY OUTWARDLY EXTENDING THROUGH THE SLOTS, THE CLIPS OF FLATTENED SECTION, AND A BRUSH STRIP COMPRISING A CHANNEL BACKING WOUND ABOUT THE MANDREL, THE CLIPS ENGAGING THE TURNS OF THE BRUSH STRIP AND MEANS SECURING THE STRIP IN THE CLIPS, SAID MEANS COMPRISING SCREWS THROUGH THE SIDES OF EACH OF THE CLIPS AND ENGAGING THE SIDE WALLS OF THE CHANNEL BACKING OF THE STRIP.