EP0803223A2

EP0803223A2 - Brush roll for a vacuum cleaner

Info

Publication number: EP0803223A2
Application number: EP97850058A
Authority: EP
Inventors: Lars Kilström; Björn Riise; Anders Haegermarck
Original assignee: Electrolux AB
Current assignee: Electrolux AB
Priority date: 1996-04-25
Filing date: 1997-04-17
Publication date: 1997-10-29
Also published as: SE9601574L; EP0803223A3; SE9601574D0

Abstract

A vacuum cleaner brush roll (13) having a core with a cylindrical outer surface (16). The core has a series of recesses (18) in which brush tufts (19) are secured. A minor part of the length of the brush tuft (19) extends, when not under load, outside the roll outer surface (16) and the brush tuft (19) is fixed at the bottom of the associated recess (18). The recess is shaped such that a portion of the brush tuft disposed within the recess can be moved in a direction perpendicular to the tuft length direction.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a vacuum cleaner brush roll having a cylindrical outer surface with several extending brush tufts.
Brush rolls of the above-described type are commonly used in upright vacuum cleaners, and in motor-driven nozzles for canister-type vacuum cleaners. The brush roll works against the floor, sets the dirt particles free, and moves the particles toward a nozzle opening. The dirt particles are transported through the nozzle opening to a dust container by air flowing toward a fan unit.
It is desirable for such brush rolls to use brush tufts having a length such that each separate bristle, due to its elasticity, contributes in throwing the dust particles toward the nozzle opening. Accordingly, the free length of the brush tuft cannot be too short. Using a brush roll with a small diameter and long-extending brush tufts, however, creates certain complications since these brush tufts have a tendency to wind up carpet fringes and threads on the roll, thereby preventing rotation of the roll. The tendency for carpet fringes to wind up on the roll decreases as the diameter of the roll increases. However, the free length of the brush tuft has to be shortened when the full diameter is increased to permit the brush roll to fit within the available space. Shorter brush tufts do not satisfactorily propel particles toward the nozzle opening. Previously known brush rolls are thus a compromise between these contradictory demands.
Therefore, there exists a need in the art for a brush roll having a large diameter, to reduce the risk of carpet fibers to wind up on the roll, while having brush tufts of a length sufficient to propel dirt particles toward the nozzle opening.

SUMMARY OF THE INVENTION

The present invention is directed toward a brush roll for an autonomous, self-guiding vacuum cleaner which operates without manual efforts or supervision and having a limited power. The brush roll is designed such that the roll does not get stuck into carpet fringes and is not prevented from rotating when contacting the floor.
In accordance with the present invention, a brush roll has a core and a plurality of brush tufts. The core has a cylindrical outer surface and a plurality of recesses. Each of the tufts is secured to the core at a bottom of an associated recess.
In further accordance with the present invention, a minor part of a length of the brush tuft extends beyond the core outer surface when not loaded and, when loaded, is moved in a direction generally perpendicualar to a length of the tuft. The brush tuft can bend so that a brush tuft tip lies near the core cylindrical outer surface.

BRIEF DESCRIPTION OF THE DRAWINGS

These and further features of the invention will be apparent with reference to the following description and drawings, wherein:

FIG. 1 is a perspective view of a self-guiding vacuum cleaner supporting a brush roll according to the invention;
FIG. 2 is a perspective view of the brush roll according to the present invention;
FIG. 3 is a section through the brush roll with a brush tuft in a non-working position, whereas;
FIG. 4 is a section through the brush roll similar to FIG. 3, but with the brush tuft in a working position in engagement with the floor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The vacuum cleaner shown in FIG. 1 comprises a chassis with a housing 10 partly shaped as a handle 11. The chassis has, at its bottom side, a brush roll 12 and a nozzle (not shown). The nozzle fluidly communicates with a chamber in the housing containing a dust container (not shown). The chamber communicates with a fan unit having an outlet 13 to atmosphere. The vacuum cleaner also has supporting wheels (not shown) and drive wheels 14 for driving and guiding the vacuum cleaner on the floor. The vacuum cleaner further comprises an electronic control system which, by means of electric components, supervises and guides the vacuum cleaner. Several rechargeable batteries (not shown) placed in the housing 10 are used as a power source for driving the brush roll, the fan unit and the driving wheels 14.
With reference to FIGS. 2-4, the brush roll 12 comprises an elongated homogeneous core 15 with a cylindrical outer surface 16. The brush roll 12 is preferably made of wood or plastic. The core 15 has, at both of its ends, shafts 17 which are rotatably supported in the vacuum cleaner. The core 15 is provided with several recesses 18 separated from each other and each receiving a brush tuft 19.
The brush tufts 19 preferably have a circular cross-section and comprise several bristles of a natural or synthetic material. Each tuft 19 is secured at the bottom 20 of an associated recess 18 and has a length such that a portion of the tuft 19, when in a non-working or at-rest position, extends somewhat outside the cylindrical outer surface 16 of the brush roll core 15 (FIG. 3). The recesses 18 are dimensioned such that the brush tufts 19 have a certain play with regard to the walls of the recess 18. In other words, the brush tufts 19 can move within the recess 18 relative to the core 15 and the core outer surface 16.
A rear wall part 21 of the recess 18, as seen in the direction of rotation R, is spaced a relatively large distance from the brush tuft 19, which means that the brush tuft 19, when sufficiently loaded, will move or bend toward the rear wall part 21. The brush tuft 19, if sufficiently loaded or overloaded, will bend so that the tip of the brush tuft 19 comes close to, or is immediately inside, the outer surface 16 of the brush roll core 15 (FIG. 4). The rear wall part 21 defining the rearward extent of the recess 18 is preferably at an angle to a diameter reference line D of the core and a brush tuft central length axis A, as shown in FIG. 3. When the brush tuft is overloaded, the brush tuft 19 bends and engages the wall 21 (FIG. 4).
The recess 18 is placed and oriented such that the length direction of the brush tuft 19 is parallel to the diameter reference line D of the core 15 while the central length axis A of the brush tuft 19 is spaced a distance from the diameter reference line D. Preferably, the recesses 18 are positioned at equal distances from each other as seen in the length direction of a longitudinal axis of the brush roll, and at equal distances from each other as seen in direction of the circumference. The last-mentioned angular distance is preferably in the range of 90-180° and, more preferably, about 150°.
The brush roll 12 operates in the following way. The brush roll 12 is rotated in the direction denoted R. When the tip of the tuft bristles engage the floor, the brush tuft 19 will normally bend somewhat without engaging the rear wall part 21 before the tip of the bristle comes free of the floor. This means that the brush tuft 19 springs forward thereby throwing free dirt particles forwards and upwards toward the nozzle opening. If the bristle tip should have a tendency to grip and start winding a carpet fringe, the brush tuft 19 will be bent to the position shown in FIG. 4, which means that the carpet fringe during continued rotation of the brush roll 12 is peeled off by the cylindrical surface 16 since the free length of the brush tuft 19 gradually decreases until the tip of the tuft 19 falls inside the outer surface 16 and the carpet fringe is free.
It should also be mentioned that although the brush roll according to the invention is mainly intended to be used with an autonomous self-guiding vacuum cleaner of the type described above, it can, of course, be used with various other types of vacuum cleaners and nozzles.
Although the present invention is described herein with particularity, it should be apparent that the scope of the invention is not limited to that shown and described herein. Rather, the present invention is capable of numerous additions, modifications, and replacements of parts without departing from the spirit and scope of the present invention, as defined by the claims appended hereto.

Claims

A vacuum cleaner brush roll (13) comprising a core with a cylindrical outer surface (16) and a plurality of brush tufts (19) extending from the core characterized in that the core has a plurality of recesses (18), each of said brush tufts (19) being secured to said roll (13) at a bottom of an associated recess (18), a minor part of a length of the brush tuft (19), when not loaded, extends beyond the roll outer surface (16), said recess being shaped so that at least a portion of the brush tuft within the recess can be moved in a direction generally perpendicular to the length direction of said tuft.
A vacuum cleaner brush roll according to claim 1, characterized in that the recess (18) and the brush tuft (19) each have a length and a shape such that the brush tuft, during rotation of the brush roll and during engagement of the brush tuft with a floor, can bend so that a tip of the brush tuft lies near the cylindrical surface (16).
A vacuum cleaner brush roll according to claim 1 or 2, characterized in that the length direction of the brush tuft, when the brush tuft is not loaded, is parallel to a diameter reference line (D) of the brush roll, a central length axis (A) of the brush tuft being spaced a distance from said diameter reference line.
A vacuum cleaner brush roll according to any of the preceding claims, characterized in that the brush tuft (19) has a generally circular cross section.
A vacuum cleaner brush roll according to any of the preceding claims, characterized in that the brush tufts (19) are spaced equal distances from one another as seen in the length direction of the brush roll and as seen in a circumferential direction of the brush roll.
A vacuum cleaner brush roll according to claim 5, wherein the angular distance in the circumferential direction is greater than 90° and less than 180°.