US3900913A

US3900913A - Core mounting assembly for rotary brooms

Info

Publication number: US3900913A
Application number: US456596A
Authority: US
Inventors: Arthur E Drumm
Original assignee: Arthur E Drumm
Current assignee: United Rotary Brush Corp
Priority date: 1974-04-01
Filing date: 1974-04-01
Publication date: 1975-08-26
Anticipated expiration: 1992-08-26

Abstract

An improved core mounting assembly is provided for securing of rotary brooms having a central, cylindrical core in fixed, driving relationship on an axle or drive shaft. A broom core of the type for which the core mounting assembly of this invention is designed to be utilized comprises an open-ended, tubular cylinder having the broom bristles mounted on the exterior surface thereof in accordance with well known prior art practices. A pair of the core mounting assemblies of this invention are mounted on a drive shaft and support a broom core in fixed, driving relationship to the shaft. Each core mounting assembly of this invention comprises a pair of parallel disposed plates positioned on the drive shaft with one plate secured in fixed driving relationship thereto. Each plate is circular and of a diameter to closely interfit within the broom core with the pair of plates having outer peripheral edges cooperatively defining an outwardly opening circumferential V-shaped groove and connecting bolts adapted to forcefully draw the two plates together axially in clamping relationship. A split circular ring of steel is disposed in the groove and displacement of the plates toward each other results in outward circumferential expansion of the ring into contacting engagement with the broom core for coaxial support of the broom core in frictional driving relationship to the axle.

Description

United States Patent Drumm ROTARY BROOMS [76] Inventor: Arthur E. Drumm, Rt. 1,

Marysville, Ohio 43040 [22] Filed: Apr. 1,1974

21 Appl. No.2 456,596

[52] U5. Cl. 15/179; 29/117; 279/2 [51] Int. Cl. A46B 13/02 [58] Field of Search 15/179, 180, 181, 182, 15/183; 279/2; 242/682; 29/117 [56] References Cited UNITED STATES PATENTS 2,365,980 12/1944 Thomas 279/2 2,647,701 8/1953 Cannard 279/2 2,734,749 2/1956 Benjamin." 279/2 2,749,133 6/1956 Rich 279/2 2,765,175 10/1956 Parker et al7 279/2 3,649,985 3/1972 Hunt 15/179 Primary ExuminerPeter Feldman Attorney, Agent, or FirmMahoney, Miller & Stebens [57] ABSTRACT An improved core mounting assembly is provided for [4 1 Aug. 26, 1975 securing of rotary brooms having a central, cylindrical core in fixed, driving relationship on an axle or drive shaft. A broom core of the type for which the core mounting assembly of this invention is designed to be utilized comprises an openended, tubular cylinder having the broom bristles mounted on the exterior surface thereof in accordance with well known prior art practices. A pair of the core mounting assemblies of this invention are mounted on a drive shaft and support a broom core in fixed, driving relationship to the shaft. Each core mounting assembly of this invention comprises a pair of parallel disposed plates positioned on the drive shaft with one plate secured in fixed driving relationship thereto. Each plate is circular and of a diameter to closely interfit within the broom core with the pair of plates having outer peripheral edges cooperatively defining an outwardly opening circumferen tial V-shaped groove and connecting bolts adapted to forcefully draw the two plates together axially in clamping relationship. A split circular ring of steel is disposed in the groove and displacement of the plates toward each other results in outward circumferential expansion of the ring into contacting engagement with the broom core for coaxial support of the broom core in frictional driving relationship to the axle.

5 Claims, 5 Drawing Figures CORE MOUNTING ASSEMBLY FOR ROTARY BROOMS BACKGROUND OF THE INVENTION Rotary brooms are widely utilized for industrial or street sweeping and one common broom construction is designated as the core-type. This type of broom comprises an elongated cylindrical core open at each end with the brush bristles or filaments being secured in various ways around the outer circumference of the core. An elongated drive shaft extends axially through the core and drivingly supports the rotary broom on a sweeping machine. A pair of core mounting assemblies are employed to secure the rotary broom through its core to the drive shaft.

Several types of core mounting assemblies are disclosed in the prior art with these prior assemblies including a circular ring of elastomeric material such as rubber carried by a circular ring device mounted on the drive shaft. The circular ring-mounting device is constructed to circumferentially expand the rubber ring into contacting engagement with the interior surface of the core. Rotational driving force is thus transmitted from the shaft to the core through the friction contact between the rubber ring and the core.

Examples of prior art core mounting assemblies are disclosed in US. Pat. Nos. 3,649,985 and 2,749,133. US. Pat. No. 2,749,133 discloses a structure that is similar to the improved core mounting assembly of this invention in that it comprises a pair of relatively axially movable ring-like members having circumferential inclined edge surfaces cooperatively defining a V-shaped groove. A closed rubber ring is mounted in the groove and is expanded radially outward when the two ringlike members are drawn together. This outward expansion causes the rubber ring to contact the inner surface of the core in frictional driving engagement. Subsequent separation of the ring-like members permits the rubber ring to contract thereby releasing the core for removal and replacement of the rotary broom.

US. Pat. No. 3,649,985 discloses a device which is functionally similar but that device does not include a V-shaped groove for the closed rubber ring. Expansion of the ring is achieved through a compression of force applied by means of opposed, axially displaceable plates. This axial compressive force results in radial expansion of the rubber ring both inwardly and outwardly.

These prior art core mounting assemblies have not proven entirely satisfactory in that the rubber ring does not provide sufficient frictional engagement with the core surface to prevent slippage. The rotary broom cores are relatively thin walled and of limited structural strength which restricts the radial force that may be accommodated thus correspondingly limited the frintional force. Also, the rubber material that is utilized for these rings is of a type that is relatively hard to have the necessary characteristics for resisting deterioration from abrasive particles encountered by rotary brooms. This hard rubber quickly develops a smooth surface with a low coefficient of friction as a result of sliding movement relative to the core and further reduces the effectiveness in providing an adequate driving engagement. The rubber ring is also an expensive component which must be replaced at frequent intervals.

LII

SUMMARY OF THE INVENTION An improved core mounting assembly is provided by this invention which comprises utilization of a split, steel ring carried by a pair of axially movable plates. The plates are adapted for mounting on a drive shaft with one plate fixed thereon in driving engagement. Each plate which is circular and of a diameter to fit with a rotary broom core has an inwardly inclined peripheral edge which cooperatively form a V-shaped groove. The steel ring is disposed in the groove and extends substantially around the circumference. Bolts extending axially through the one plate and threaded into the other plate function to draw the plates together thereby constricting the V-shaped groove and causing the steel ring to be displaced radially outward and into contacting engagement with the interior surface of a broom core. Such radial displacement is possible because the ring is split and the several components are relatively dimensioned to result in the outermost periphery of the ring projecting radially beyond the outer periphery of the plates. A series of rib-like projection may be formed on surface of the steel ring to enhance frictional engagement.

These and other objects and advantages of this invention will be readily apparent from the following detailed description of an embodiment of this invention and the accompanying drawings.

DESCRIPTION OF THE DRAWING FIGURES FIG. 1 is a medial longitudinal sectional view of a core mounting assembly embodying this invention disposed in supporting relationship to a core-type rotary broom.

FIG. 2 is an end elevational view on an enlarged scale of the core mounting assembly as seen on a plane extending through line 2-2 of FIG. 1.

FIG. 3 is a sectional view taken along line 33 of FIG. 2.

FIG. 4 is an end elevational view similar to FIG. 2 but on a reduced scale showing a modification.

FIG. 5 is a fragmentary sectional view on an enlarged scale taken along line 55 of FIG. 4.

DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT FIG. 1 of the drawings generally illustrates utilization of a pair of core mounting assemblies 10 embodying this invention. The two assemblies 10 are positioned in axially spaced relationship on an elongated drive shaft 1 1 which forms a part of a sweeping machine that is not otherwise illustrated. It will also be understood that a rotative driving force will be applied to the shaft 11 of this rotary broom assembly by well known but not illustrated mechanisms.

A rotary broom 12 of the core-type is generally illustrated in FIG. 1 to show how a broom is mounted and supported on the core mounting assemblies. A broom of this type includes a central core 13 which is an elongated, open-ended cylinder having an outer surface on which are mounted the flexible brush-forming filaments 14. It will be understood that the rotary broom 12 is shown in section for illustrative clarity as to the invention and that the broom is cylindrically configured. The core 13 is shown as a thin walled tube without indication of any means for attachment of the brush filaments as such means are well known in the prior art.

It will be sufficient for purpose of fully disclosing this invention to note that the core 13 has a smooth, cylindrical surface 15.

One of the two core mounting assemblies is shown in greater detail in FIGS. 2 and 3. Each assembly 10 is mounted on the drive shaft 11 in a position to be closely adjacent but spaced slightly inward of a respective open end of the core 13.

Forming a core mounting assembly 10 are a pair of

circular plates

16 and 17 and a split ring 18. One of the circular plates 16 is formed with a central aperture which closely fits on the shaft 11 and is secured to the shaft for transmitting rotative motion. Mounting of the plates may employ any type of shaft connecting devices although, in the illustrative embodiment, the plate 16 is fabricated from steel and is permanently affixed to the shaft by welding at the outer surface of the plate and indicated at 19. The second plate 17, also fabricated from steel, has a central aperture 20 of a diameter slightly larger than that of the shaft to readily permit axial movement of the plate along the shaft.

Interconnecting the two

plates

16 and 17 are fastening means which maintain the plates in coaxially aligned relationship and provide a means for drawing the plates axially together. In this illustrative embodiment, the fastening means includes four cap screws 21 which extend axially through respective apertures 22 formed in plate 16 and are threaded into sockets 23 formed in plate 17. Rotation of the cap screws 21 will thus permit the

plates

16 and 17 to relatively separate or will draw the plates together as determined by the direction of screw rotation.

Each of the

plates

16 and 17 is formed with respective inclined

peripheral edge surface

24 and 25. The direction of inclination is inwardly from the outer circumference toward a

respective side surface

16a, 17a of the two plates which are juxtaposed. This configuration results in a radially outward opening V-shaped groove 26 defined by the two inclined surfaces. It will be noted that the outer

circumferential edge surface

16b, 17b of each plate is of a slightly lesser diameter than that of the interior surface of the core 13. This permits the core 13 to be slid axially over the

plates

16 and 17 for purposes of removing and replacing of a rotary broom 12.

The split ring 18, in accordance with this invention, is formed from a round steel rod and is of a length to extend substantially around the

circular plates

16 and 17 in the groove 26 defined by these plates. The terminal ends 27 and 28 of the rod are shown spaced apart in FIGS. 2 and 3 with this spacing being that which is adequate to permit constriction of the ring from the illustrated diameter. This rod utilized in fabrication of this ring 18 is of a diameter to be fully contained within the groove 26 when the plates 16 are spaced apart a distance greater than that shown in FIG. 3. In that situation, the outermost circumferential surface portions of the ring 18 will at least be of the same, if not lesser, diameter than the peripheral edge surface 16b, l7b of the circular plates. This permits the core 13 to slide axially over the

plates

16, 17 without interference. Constriction of the ring 18 in this manner is accomplished by forming the ring with a slightly smaller diameter than the minimum required and thereby utilizing the resilient characteristic of steel.

Drawing the

plates

16 and 17 axially toward each other by means of the cap screws 21 will cause the

inclined surfaces

24 and 25 to cooperatively bear against the inwardly facing surface portions of the ring 18 resulting in radially outward expansion of the ring. Radially outward expansion of the ring 18 will bring the outermost circumferential surface portions into contacting engagement with the interior surface 15 of the core 13 as shown in FIGS. 2 and 3. The ring 18 will be expanded substantially uniformly and will maintain the coaxial alignment of the rotary broom core 13 relative to the drive shaft 11 while supporting the core in fixed, driven relationship. Appropriate tightening of the cap screws 21 produces the necessary friction driving engagement substantially uniformly around the core without distorting the thin walled core.

The frictional driving engagement between the ring 18 and both the core 13 and plate surfaces 24 and 25 is greatly enhanced by formation of rib-like projections 29 on the ring. These projections 29 extend circumferentially around the rod and effectively increase the frictional driving engagement. In the illustrative embodiment the projections 29 do not extend continuously around the rod and are offset axially of the rod but this is not considered a limitation as to formation of the projections. This frictional driving engagement may be further enhanced, if necessary, by forming the ring with a flattened outer peripheral surface having a larger area for contactly engaging the inner surface of the core.

For installations where the problem of the core slipping during use appears to be of serious consequence, a key-type interlock may be incorporated in the illustrated structure. FIGS. 4 and 5 are illustrative of an embodiment of a key-type interlock where the structure is the same as seen in the end view of FIG. 2. All components are the same as previously described with respect to FIGS. 1, 2 and 3 with the exception of forming aligned slots or

notches

31 and 32 in the

plates

16 and 17 and attaching a key 33 to the inner surface of the core 13. In this modification, the key 33 is an elongated bar of square cross-section which is secured to the core in axially disposed relationship as by welding in the case of metal components. Each of the

notches

31 and 32 are configured to cooperatively engage the key 33 to transmit a rotative driving force to the core and to also permit the core to be moved axially for replacement purposes. The split ring 18 still functions to support the core in coaxial alignment with the shaft 11 with the terminal ends 27 and 28 of the ring being relatively spaced to avoid interference with the key.

Although the preferred embodiment illustrated and described in detail has the peripheral edge surface of both plates inclined, it will be understood that the outwardly opening groove can be formed by having the peripheral edge of only one plate so inclined. The functional operation for expanding and radially displacing the ring will be the same. Also, the angle of inclination may be varied and the surface need not be straight lined. I

To facilitate engagement of the drive shaft and core mounting assembly with the driving mechanism of a sweeping machine, the circular plate 16 is provided with plurality of threaded sockets 30 formed on a bolt circle. A coupling member (not shown) which forms a part of the driving mechanism is readily secured to the end face of the plate 16 by cap screws (not shown) to complete a drive connection.

Utilization of a core mounting assembly fabricated in accordance with this invention will be readily understood from the preceeding detailed description of an embodiment thereof and the accompanying drawings. It will also be readily apparent that an improved core mounting assembly is provided for use with core-type rotary brooms and which has the advantages of enhanced frictional engagement between the mounting assembly and improved durability through incorporation of a split ring fabricated from steel.

Having thus described the invention, what is claimed l. A core mounting assembly comprising a drive shaft, a pair of circular plates positioned on said drive shaft for revolution therewith in a plane transverse to the axis of rotation, said plates dis posed axially spaced to each other and relatively axially movable with one said plate adapted to be drivingly mounted in supported relationship on a drive shaft, said plate being fixed to said shaft axially and the other plate being slidable axially of the shaft, at least one of said plates having a circumferential edge surface inclined inwardly toward a side surface thereof disposed adjacent a side surface of the other plate whereby said inclined circumferential edge surface cooperatively define an outwardly opening groove with the other of said plates,

fastening means mechanically coupling said plates in a predetermined axially-spaced relationship and selectively operable to axially displace said plates towards each other,

said fastening means comprising fastening members radially outwardly of said shaft and extending between said plates to which they are operatively connected, and

a split ring disposed in said groove formed by said plates and extending substantially around said plates, said ring being expansible radially outward in response to relative displacement of said plates toward each other to frictionally engage the inner surface of a circumscribing circular member and being formed from a resilient metal material so that its ends can be spread apart to be positioned in said groove and normally constricting to an internal diameter less than the external diameter of said plates so it will engage said inclined edge surface of the plate and to an external diameter less than the external diameter of said plates so it will be positioned fully within said groove when said plates are in said axially spaced relationship but will expand radially outwardly of said groove into engagement with said circular member upon displacement of said plates axially towards each other.

2. A core mounting assembly according to claim 1 wherein said ring is formed from a cylindrical steel rod with a plurality of rib-like projections extending in radially outward relationship to the ring and disposed in circumferentially spaced relationship, and with a plurality of spaced apart, rib-like projections extending in radially inward relationship to the ring into engagement with the inclined circumferential edge surface of said plate.

3. A core mounting assembly comprising a pair of circular plates adapted to be positioned on a drive shaft for revolution therewith in a plane transverse to the axis of rotation, said plates disposed axially spaced to each other and relatively axially movable with one said plate adapted to be drivingly mounted in supported relationship on a drive shaft, at least one of said plates having a circumferential edge surface inclined inwardly toward a side surface thereof disposed adjacent a side surface of the other plate whereby said inclined circumferential edge surface cooperatively defines an outwardly opening groove with the other of said plates,

fastening means mechanically coupling said plates and selectively operable to axially displace said plates towards each other, and

a split ring disposed in said groove formed by said plates and extending substantially around said plates, said ring being expansible radially outward in response to relative displacement of said plates toward each other to frictionally engage the inner surface of a circumscribing circular member and being formed from a resilient material,

each of said circular plates having an outwardly opening notch formed in the marginal edge portion at the outer periphery thereof, said notches in each plate being relatively aligned axially of the assembly and configured to cooperatively interengage with an elongated axially extending key secured to the inner surface of a circumscribing circular member with the key being movable axially through said notches, said split ring having terminal ends relatively spaced apart and disposed at relatively opposite sides of said notches.

4. A core mounting assembly according to claim 3 wherein both of said circular plates have a circumferential edge surface inclined inwardly toward a side surface thereof disposed adjacent a side surface of the other plate.

5. A core mounting assembly according to claim 2 wherein both of said circular plates have a circumferential edge surface inclined inwardly toward a side surface thereof disposed adjacent a side surface of the other plate to form said groove, said fastening members comprising a plurality of cap screws angularly disposed about the shaft passing through apertures in one of said plates and threaded into aligning sockets in the other of said plates.

Claims

1. A core mounting assembly comprIsing a drive shaft, a pair of circular plates positioned on said drive shaft for revolution therewith in a plane transverse to the axis of rotation, said plates disposed axially spaced to each other and relatively axially movable with one said plate adapted to be drivingly mounted in supported relationship on a drive shaft, said plate being fixed to said shaft axially and the other plate being slidable axially of the shaft, at least one of said plates having a circumferential edge surface inclined inwardly toward a side surface thereof disposed adjacent a side surface of the other plate whereby said inclined circumferential edge surface cooperatively define an outwardly opening groove with the other of said plates, fastening means mechanically coupling said plates in a predetermined axially-spaced relationship and selectively operable to axially displace said plates towards each other, said fastening means comprising fastening members radially outwardly of said shaft and extending between said plates to which they are operatively connected, and a split ring disposed in said groove formed by said plates and extending substantially around said plates, said ring being expansible radially outward in response to relative displacement of said plates toward each other to frictionally engage the inner surface of a circumscribing circular member and being formed from a resilient metal material so that its ends can be spread apart to be positioned in said groove and normally constricting to an internal diameter less than the external diameter of said plates so it will engage said inclined edge surface of the plate and to an external diameter less than the external diameter of said plates so it will be positioned fully within said groove when said plates are in said axially spaced relationship but will expand radially outwardly of said groove into engagement with said circular member upon displacement of said plates axially towards each other.

3. A core mounting assembly comprising a pair of circular plates adapted to be positioned on a drive shaft for revolution therewith in a plane transverse to the axis of rotation, said plates disposed axially spaced to each other and relatively axially movable with one said plate adapted to be drivingly mounted in supported relationship on a drive shaft, at least one of said plates having a circumferential edge surface inclined inwardly toward a side surface thereof disposed adjacent a side surface of the other plate whereby said inclined circumferential edge surface cooperatively defines an outwardly opening groove with the other of said plates, fastening means mechanically coupling said plates and selectively operable to axially displace said plates towards each other, and a split ring disposed in said groove formed by said plates and extending substantially around said plates, said ring being expansible radially outward in response to relative displacement of said plates toward each other to frictionally engage the inner surface of a circumscribing circular member and being formed from a resilient material, each of said circular plates having an outwardly opening notch formed in the marginal edge portion at the outer periphery thereof, said notches in each plate being relatively aligned axially of the assembly and configured to cooperatively interengage with an elongated axially extending key secured to the inner surface of a circumscribing circular member with the key being movable axially through said notches, said split ring having terminal ends relatively spaced apart and disposed at relatively opposite sides of said notches.