US3101501A - Rotary broom for street sweeper - Google Patents

Description

Aug. 27, 1963 J. P. HORTON ETAL 3,101,501

ROTARY BROOM FOR STREET SWEEPER 2 Sheets-Sheet 1 Filed March 6, 1961 MOUNTING PLAT J. P. HORTON ETAL ROTARY BROOM FOR STREET SWEEPER 2 Sheets-Sheet 2 POSITIONING LUGS 6| ms; PLATE Aug. 27, 1963 Filed March 6, 1961 Ute Stes Patent Ofice 3,191,501 Patented Aug. 27, 1963 3,101,501 I ROTARY BROOM FOR STREET SWEEPER John P. Horton, 79 Old Fort Road, Bernardsville, N.J.; George E. Berry, Spring Run-Lanm-Maltinsville, N.J.;

and John E. Stirling, 1041 Wychw'ood Road, Westfield, NJ. Filed Mar. 6, 1961, Ser. No. 93,558

7 Claims. (Q1. 15- -1 80) This invention relates to a rotary broom for street sweepers. f i I I Rotary brooms are often used as side brooms having a vertical axis of rotation in connectionwith a horizontally disposed brush roller. The rotary broom'normall y serves to sweep the street dirt" from the gutter inward the assembly of this broom, the annular wire sections mento the roller brush which then ensures the further ,re- 1 associated with the provision of practicable brooms of this a type are quite dilferent from those associated with the provision of small industrial brushes of the'same general shape. 7

In the conventional type of rotarybroom, the brush back is a circular plate, or ring, or ser-ies of circular segments which, in the vicinity of a periphery, provided with one or more circular series of holes extending therethrough having a square, ,or circular, cross section and extending obliquely outward in a direction corresponding to the desired direction of the bristles in the finished rotary broom.' In each of the holes, a bunch of hair-pin shaped bristles is inserted from the rear side, or top side, of the brush back with its legs on either' side of a pin or hinder wire extending across the holes: The bristles are secured onto the back by tightening a ring, or plate, toward-the rear, or top, side ofvthe brush back proper. (Such rings, or plates, are often an integral part of the street sweeping machineon which the brushis mounted). The bent portion of the bunches of bristles are'thus clamped between the additional plate and the pins or binder wire extending transversely'across the holes of'thebr'ush back and between the legs of the bunches of bristles. a f i The. manufacture of these known rotary brooms very laborious and must, as far-as a substantialpart of the production is concernedg'be effected manually and consequently the production costs are very high. Also such a structure puts very heavy strain upoii'the'binder wire, it used, or the like. Any replacement of,worn brush material must be done manually and is likewise expensive, representing'an expense to the 'user comparable to the cost of anew broom. U Since a'considerable time is required to remove worn and insert new brush.

material, the user of the broom often feelsc'ompelled to keep spare brooms on hand'in order to keep the sweepijng machines operating, thus' representing an increased eco-;

nomic burden. 1

Recently efforts have been made in Europe to overcome many: of the aforementioned defects of conventional rotary brooms forstreetsweepers. In accordance with oneembodiment, a rotary broom for street sweepers is. provided comprisinga circular, steel broom back having" a"frusto-conical, outwardlyfla're'd', steel ,flangej we'lded thereto and an annular section of] hair-pin'shaped wire bristles secured in a U-shapedring by'wire's andrelea'sably vcl'amped between the broom backand a circularsteel plate ring having an outer diameter onlyf slightly less f than the 'outer diameter of the inside base of the broom backilf for street sweepers, a continuous-layer of steel sweeper a of breakage of the broom back.

tioned above -is positioned between the frusto-conical broom back and the clamping plate ring and, by means of a special assembly device, the clamping, ring is then forced in the direction of the, inside face of the broom back until the U-ring is firmly clamped between the clamping ring and the inside face of the broom back. The ring plate is held in releasable clamping relation by a plurality of threaded bolts extending from the broom back through both the broom back and the clamping plate ring and held in clamping position by suitable, nuts tightly screwed onto the bolt threads. In this way, the annular V-shaped assembly of bristles is forced downwardly in the direction, of the broom back and the bristles are forced into contact with the frusto-conical flange and therebelow to form a frusto-conical crown of brush material. The clamping plate is provided with upwardly extending prongs which impede the rotation of the U-shaped ring and brush material. During the assembly of this broom, the sides of the U-shaped ring are close and thereafter assist in securing the hair-pin shaped wires Considerable force is required to bring the broom back and clamping I plate into contact with the U-shaped ring.

H Iti-s a general object of this invention to provide a novel rotary broom for street sweepers which preserves the advantages of the recently developed broom mentioned above whilebring-ing about certain other advantages. It is another object of the invention to provide a rotary broom w'hich is especially easy to assemble and disassemble withor without-the use of special tools. It is an importantobject of this invention to provide a broom fora rotary street sweeper in which the bristles are'maintained in a vertical position during use so that the stiff but flexible bristles will exert a flipping action on stones or the like when it comes in contact with such articles. It is a special object of the invention to provide arotary broom which-permits thorough cleaning of street gutters by close approach to the curb without danger It is yet another special object of the invention to provide a rotary broom in which the rotation of the brush element relative to thebrush back is inhibited. It is yet another object of this invention to provide indentation, or pockets, in the fru-sto- 1 conical brush crow-nthat will facilitate a more effective rem-oval of larger objects, such as stones, from the gutter.

It is another important object of the invention to provide: a broom for a rotary street sweeper which willachieve' the above-mentioned objectives Without overloading the Other objects and more detailed description which follows. I

i It now been found that an especially effective and especially easily assembled and disassembled relatively light rotary broom of the latter type disclosed abovecan be provided having a unitaryback and a unitary section of annular brush material which can be releasably clamped. to the brhsh back in such a way that the foregoing objectives can be achieved.

" The features of the improved rotary broomof'this in In-thefproduction of thistype of known rotary broom 'vention 'canbe best appreciated from a consideration at J the ggir'ob-lems "experien-ced 'in the us'e' o'f kn'own rotary; brooms for street sweepers, especially knowh rotary brooms of the latter type mentioned above." lnlthe useg banish brooms," it-ha's'been 'tound it is'extremely im'-" portant that the wire of the brush section be held, not only originally but during operation, in a substantially radial direction. It the wires are not so held, they tend to slant back away from the direction of rotation of the broom and consequently lose a great proportion of the flipping action that is so desirable for a satisfactory sweeping operation. Further-more, if the wires slant backwards, the vertical distance between the lipof the housing of the broom back and the ground is decreased even though there may be no wear on the brush wire and the life of the broom is correspondingly decreased. Thus both for better sweeping and longer life, it is important to hold the broom wire in a radial posit-ion.

It has been found that the wires can be held in a radial position by providing a downwardly extending portion of the brush back with inwardly extending radial holding elements such as ribs or fins. These radial holding elements serve a plurality of additional 'functionsincluding reinforcing the broom back and a control of the wire down to the point where it leaves the housing of the broom back.

Also in the use of brooms having a steel structure as described in the prior :art, it has been found that such materials add excessive Weight to the broom to the point of overloading the suspension system on the sweeper. This overloading also causes the broom to bear too heavily on the street with a consequent excessive wear on the bristles. It appears that this difiiculty could be overcome by making the broom back and the clamping element out of a lightweight material. For practical reasons, aluminum casting-s were selected to achieve control over the Weight problem. It was found that rotary broom backs made from aluminum castings solved the weight problem but such brooms could not be attached to the mounting plate of the rotor of a sweeper in the customary manner by bolts-extending through the mounting plate and screwed into the back of the broom due to the fact that threads cut into the aluminum castings were bound to deform and strip in use. disadvantage was overcome by directly casting threaded inserts into the aluminum casting made of hard and non-deformable metal such as steel. Where necessary, the steel inserts were provided with shoulders to prevent the insert from being stripped out of the aluminum casting during use.

Likewise, by providing threaded steel inserts in the clamping element, it was found that the clamping element could be releasably clamped to the broom back so as to hold the annular section of bristles in the broom by bolts extending through the broom back and directly screwed into these inserts. This procedure avoided the necessity for using bolts which were held in clamping relation by nuts tightened onto the threaded end of the bolt as disclosed in the prior art. Such a prior art procedure necessitates the .use of conventional locking means which were not wholly satisfactory in use due to the tact that nuts tended to loosen during use of the broom. In accordance with this invention, it has been found that the problem of such loosening can be eliminated for most installations. This desirable result is accomplished by the recessing of the bolts in the top of the broom back a distance corresponding to the combined height of the bolt head and the washer used therewith. In this way, the bolt head is flush with the top of the broom back so that when the broom is mounted on a conventional sweeper mounting plate, the mounting plate covers the bolt heads and any tendency of the bolts to loosen in use is thereby prevented by the mounting plate being directly in contact with the top of the bolt heads. V

In the use of gutter brooms containing trusto-conical flanges of the prior art, it has been found that careless use of the broom in the effective cleaning of gutters may result in the outwardly extending flanges of the broom back coming into contact with the curb whereby the flanges may be damaged or even broken. On the other hand, extreme care in avoiding damage to the broom by avoiding all contact with the curb often impedes eflective cleaning of the streets. Yet an outwardly flared flange is desirable to properly position the bristles relative to the back of the broom. These problems have been overcome in the instant broom by providing a brush back with a downwardly extending flange having an at least partially vertical outer wall and an outwardly tapering inner wall. By providing an outer wall at least having a vertical section at its outermost periphery, greater bearing surfaces normally provided by multiple point contact with the curb when the sweeping machine closely approaches the curb thereby lessening the likelihood of damage, or breakage. Furthermore, due to the normal tilting of the rotary broom in the direction of the curb, any single point contact of the outside surface of the broom back with the curb will normally take place at a point removed from the outer periphery of the flange thereby lessening the leverage impact of such a contact.

'In the use of rotary brooms containing truev trustoconicalcrowns of brush material, as disclosed in the prior art, it has been found that such brooms are not always effective in removing large articles, such as stones, which have a tendency to be tossed down the street ahead of such brooms rather than being swept in toward the center of the street where they can be removed by the horizontal roller sweepers. In order to overcome this difficulty, the broom back hereof have been provided with internally extending protuberances, such as lugs, at the inside of the lower extremity of the downwardly extend-- ing flanges. These lugs, or the like, cause circumferential inden-tions in the crown of the brush material which have a tendency to catch stones and the like and throw them away from the curb towards the horizontal roller sweeper.

Additionally, it has been found that the packaging, manipulation and assembly of the bristles which constitute the brush material used in therotary broom, and replacement of the brush material, can be greatly facilitated if p the brush material is pro-assembled into a unitary flat, or

planar, annulus having its inner periphery fixedly positioned and bound as with a bonding material or a. metallic clamping element. For example, a very satisfactory brush tiller can be obtained from crimped wires of the type suitable for use in rotary brooms for street sweepers by placing layers of such wires across the open jaws ofa U-shaped ring, forcing the central portion of the. wires downwardly into contact with the inside base of the ring, as with binder wire, and thereafter hydraulically closing the jaws of the ring to force thewires into a substantially flat annular section of brush material held in the ring by the binder wire and the gripping effect of the closed jaws of the ring. This unitary annular wire filler may be easily packaged when shipped as a replacement and, easily clamped to the brush back by the owner of the street sweeping machine in the manner set out below.

Finally, it has been found that the brush material is more easily assembled to form the rotary broom if a specially designed clamping element is provided. It has been found that it is diflicult to assemble very stiff wire bristles when the clamping element is of approximately the same diameter as the base face of the brush back as shown in the prior The clamping element is also prefer-ably made of aluminum casting provided with threaded insets of harder material such as steel. The clamping element is cast so that its structure complements the functioning of the unitary brush back in a manner which will be apparent from the more detailed description below. In a preferred embodiment the clamping element. constitutes asubstantially bell-shaped ring having a flat annular lower extremity of the bell-shaped portion assumes aposition in close proximity tothe radial fins of the broom back thereby facilitating the holding of the bristles in a vertical position relative ,to the broom back when th broom -is in use. 7 V .3 i The broom hereof may be readily assembledbyplacing the clamping element on asupporting device and positioning the clamping ring of the assembled bristles. over positioning lugs provided on the clamping element. Then the broom back is placed over the assembled bristles with the bolt holes thereof in alignment with the threaded inserts in the clamping element. Upon inserting the bolts and tightening them by screwing them into the-threaded inserts inthe clamping element, the; inner peripherytof brush material is-forced into releasableclamping relationship with the inside face of the broom back. By providing a clamping element-with an appropriate outer diameter in the region where it cpntactsthe inner region of the annular brush material, the broom may be assembled without the necessity for the use of a special tool. The required use of special tools has obvious commercial disadvantages. Furthermore, the diameter of the clamping element where it first contacts the inner'region of the brush material and the outward. taper to the inside of the flange of the brush back may becorrelated so that upon assemblying the broom the curvature impart-ed to the brush material does not place an-undue stresson the bristles and the bristles conform to thettaper over a large bearing area, In the use'of a true firusto-conical flange as shown in the prior art, it is difficult to bring the bristles into contact with the flange-over more than a limited area withoutputting undue stress on the bristles. Under either circumstance, the useful life of the bristles is importantly lessened. H t 1 plhe invention is more fully explained in the following description referring to the accompanying drawings representing a specific illustrative embodiment of the improvedrotary broom, in which Y a I j s 1 FIG. l showsa fragmentary vertical {,CIOSS sectional view of an-assembl ed,broorn attached tothe mounting plate of the rotor of a street sweeper; r V t :FIG. 2 shows .a fragmentary vertical cross sectional view of the various elements of the broom in a position ready for finalassembly; p FIG. fishows a fragmentary bottom view or the unitary clamping element in perspective 5.; ,EIG. 4shows a fragmentary bottomview of the unitary broom back in perspective and; p V FIG. 5 shows 'a perspective View of the assembled broom mounted onthe've'rtieal rotor of a street sweeper. t Referring, tothe drawings where the same numbers are used to representthe various elements of the broom and the rotor to which it is designed to be attached, it will be seen the broom compn'sesalunit-ary aluminum back having a unitary annular brush section ztl clamped tothe back 10 by a unitary aluminum clamping element 30 releasably held in clamping relationby bolts 40 extending through the back '10 and screwed into the clamping element 30. 'As most-clearlyshown in FIGS. 1, 2, 4 and 5, the back '10 is provided a downwardly depending' flange 11 having avertical peripheral outer side wall 12 and radial-inwardly extending fins 13. The unitary back is provided with threaded steel inserts '14 cast thereinto for receiving the bolts 50 whichfirmly attach the back of thebroom 10 tothe mounting plate 60 attached to the rotor shaft 61. The back i10,is alsotprovided with mounting pads 15, indenting lugs16,' a series of annular bolt holes 177' for receiving bolts'40, and recessed portions 18 for receiving the heads 41 ofbolts 40 and the washers 42' used in association therewith. 1 It will be noted the bolt holes -17 are located at a position removed from the a'xis'iof theibroomwandmin a peripheral region of the-top of -the, broom back relative to. theiaxis "or the broom. Due to the torque-onthe-relatively large rotary brooms forstreet sweepers it is impractical to clamp the brush material to the brush back-axially; i

The inside surface 19 of the flange 11 is curved so as to conform substantially to the natural curvature of the broom bristles when the annular section of crimped steel Wire Zttyis heldin clamping relation to the back 10. It will be observed further that the radial fins 13 extend into the annular section of brush material to the region of the lower lip of the clamping element 30 where they function tohold the broom wire in a vertical position when the broom is in operation and, at the same time, function to inhibit the rotation of brush material relative to the broom back 10.

bell-shaped flange3-2 is provided with a series of threaded steel inserts 33 cast thereinto for receiving the threaded bolts 41). The cl ampingelement 30 -is provided with a suitable number of positioninglugs 34so'that the clamp- .ing ring 21 can be readily centered over the clamping element 38' to facilitate assembly and with a plurality of reinforcing ribs 35 which provide added strength to the clamping element without requiring excessive weight. The unitary clamping element 30 is constructed so that it; functions to' complement the functioning of the unitary back- 10 Thus in the assembled broom, when the annular section of brush material 20 is firmly clamped in place, the flat top surface 31 comes in positive contact with the surface of positioning lugs 15 and the lowerlip of the flange 3 2 is in. closeproximity to the radial fins '13 ofthe broom back 10 sothat the broom bristles will be separated into a plunality of vertical sections by the nadial.fi=ns'.- 'In this way, the bristles are supported at the point wherethey leave the broom housing yet they are not subjected toexce'ssivefatigue due to the fact the bristles are supported linearly by the radial fins and one another rather than being clamped, or supported, only at thepoint where they leave the clamping ring.'

It will be seenthat some of the advantages of the radial fins nwhich. support the bristles and hold them in a vertical position could be supplied by outwardly extending radial fins on they clamping element 30 rather than as inwardly extending radial fins on the broom back .10. it will .be apparent, however, that the radial fins on the broom back. afford structural support for exposed flange ll'and aiford better support for the bristles onthe outer periphery of the brush crown where support is most needed'.

'As-best illustrated in FIGS. land 2, it can be seen the broom hereof may be economically produced and easily assembled and disassembled in the following manner.

, Firstly, the unitary aluminum broom back 10 and the complementary unitary aluminum clamping element 30 are precast and the annular section of brush material 20 is preassembled in a manner disclosed above. Secondly, the clamping element 30 is positioned on asupport (not shown) and the annular ring 21 holding the annular section of brushmaterial is positioned over the posi tioning lugs 34. ,Thirdly, the bolt holes 17 of back '10 are aligned with the threaded steel inserts -33 of clamping element 30 and boltsA-tl' inserted 'into bolt holes 17 supported on washers 4:1 andfi-nitially screwed into thread-Y ed inserts 33'a'sFshown infF IG Z.v .Finally the bolts are tightened until the flat top 31 'of clamping element 30.

between a shoulder ofithe flange 31 of the clamping ele-. ment 3'0 and'the inside face of the broom back 10 with jaw 24 restingcn the' shou1der of flange 32rand jaw 23 in contact'with' the inside face of the broom back 10. If desired, once the broomis assembled the bolts 40 used in assembling the broom may be replaced with shorter bolts to avoid damage or breakage in use.

As shown, the annular top 31 of the clamping element 30 has an outer diameter substantially less than the diameter of the inner face of the broom back It so that when the annular section oi brush material 20 is held in clamping relation with the broom back lit the bristles of the broom are bent over a gradual curvature not placing an undue stress on the bristles while at the same time contacting the curved inside surface 19 of the broom back '10 over a wide bearing area. It will be apparent that the outer diameter of the positioning lugs 3'4 of the clamping element 30 and the curvature of the outwardly tapered inner surface 19 of the flange 11. of the broom back may be selected in conformity with the physical characteristics of the bristles contained in the annular section of brush material 20 so that the composite objectives of ease of assembly, proper sweeping angle for the brush material, and avoidance of undue stress on the brush material are achieved.

The local indentations in the outer periphery of the crown brush material imparted by the indenting lugs 16 are most clearly shown in the perspective view of an assembled and mounted broom in FIG. 5.

A rotary broom having the above disclosed features is very economical, assures ease of assembly and disassembly, has superior service life, and permits thorough cleaning of street gutters without the danger of damage or breakage.

The bristles used in the brooms of this invention may be those heretofore used in the production of rotary brooms. However, in order to obtain the objectives of the invention, the brush material should be still but flexible. Crimped steel wire has proven very satisfactory. Other materials such as straight steel wire, plastic filaments, etc. having these characteristics of stiffness and flexibility may also-he suitable.

While the annular section of brush material is disclosed as a continuous section, it will be apparent that discontinuous sections of brush material, or tufts, could be provided which would be supported in a vertical position in the manner described above.

It will be understood that flange is used herein to indicate a member depending from the annular broom back or from the annular back of the clamping element and providing a circumferentially continuous surface therebelow.

It will be obvious that the invention is not limited to the particular representative structural elements shown in the drawings. Modifications in the structural details adapted to achieve the objectives of the invention will be apparent to those skilled in the art of producing rotary brooms (for street sweepers without departing from the spirit of the invention or its scope as defined in the appended claims.

What is claimed is: j

1. A rotary broom tor street sweepers, comprising a brush back having :a downwardly extending flange, clamping means underlying said back, means releasably holding said clamping means. to said back, an easily removable annular section of brush material having an inner portion of continuous brush material clamped between said back and said clamping means and having other portions thereof passing through the space between said flange and said clamp-ing means and extending downwardly from the periphery of said flange, and means associated with said flange and said clamping means and extending into said other portions of the brush material vertically supporting it in the peripheral region of said flange.

2. A rotary broom for street sweepers, comprising (a) a brush back having a downwardly extending flange provided with inwardly extending radial means, (12) clampingmeans underlying said back extending into proximity to other portions thereof passing through the space between said flange and said clamping means and extending downwardly trom the periphery of said flange.

, 3. A rotary broom for street sweepers, comprising a brush back having a downwardly extending flange provided with peripheral inwardly extending radial fins, clamping means underlying said back having a downwardly extending flange extending in proximity to said fins when in clamping position, means rel'easably holding said clamping means to said back, an easily removable annular section of brush material having its inner portion clamped between said b'ack' and said clamping means and having other portions thereof passing through the space between said first flange and said clamping means and extending downwardly from the periphery of said first flange.

'4. -A rotary broom for street sweepers, comprising a brush back having a downwardly extending flange provided with outwardly tapered inner wall and inwardly extending radial fins, clamping means underlying said back having a downwardly extending flange extending in proximity to said fins when in clamping position, means releasably holding said clamping means to said back, an easily removable annular section of brushmaterial having its inner portion clamped between said back and said clamping means and having other portions. thereof passing thnoughthe space between said first flange and said clamping means and extending downwardly from the periphery of said first flange.

5. A rotary broom for street sweepers, comprising a brush back provided with a downwardly extending flange having outwardly tapered inner walls, inwardly extending fins and substantially vertical peripheral outer walls; clamping means underlying said back extending into proximity to said fins when in clamping position; means releasably holding said clamping means to said back; an easily removable annular section of brush material having an inner portion of continuous brush material clamped between said back and said clamping means and having other portions thereof passing through the space be tween said flange 'and said clamping means and extending downwardly from the periphery of said flange.

6. A back tor rotary brooms compnfsing a unitary annulus of light weight metal provided with a flange having an outwardly flared and concavely curved inner wall and inwardly extending radial. fins. V

7. A back tor rotary brooms comprising a unitary annular aluminum casting having a flange with outwardly tapered concavely curved inner walls, substantially vertical peripheral outer walls and inwardly extending radial fins; said back having threaded insertsof harder difiiculty deformable metal located in peripheral regions in the top thereof with respect to the axis of the broom back adapted to receive threaded bolts for attaching the broom back to 'a mounting plate of a rotor.

References Cited in the file of this patent UNITED STATES PATENTS France May 9,1960

Claims (1)

1. A ROTARY BROOM FOR STREET SWEEPERS, COMPRISING A BRUSH BACK HAVING A DOWNWARDLY EXTENDING FLANGE, CLAMPING MEANS UNDERLYING SAID BACK, MEANS RELEASABLY HOLDING SAID CLAMPING MEANS TO SAID BACK, AND EASILY REMOVABLE ANNULAR SECTION OF BRUSH MATERIAL HAVING AN INNER PORTION OF CONTINUOUS BRUSH MATERIAL CLAMPED BETWEEN SAID BACK AND SAID CLAMPING MEANS AND HAVING OTHER PORTIONS THEREOF PASSING THROUGH THE SPACE BETWEEN SAID FLANGE AND SAID CLAMPING MEANS AND EXTENDING DOWNWARDLY FROM THE PERIPHERY OF SAID FLANGE, AND MEANS ASSOCIATED WITH SAID FLANGE AND SAID CLAMPING MEANS AND EXTENDING INTO SAID OTHER PORTIONS OF THE BRUSH MATERIAL VERTICALLY SUPPORTING IT IN THE PERIPHERAL REGION OF SAID FLANGE.

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