BRUSH ENTANGLEMENT PREVENTION APPARATUS IN AUTONOMOUS ROBOTIC VACUUMS

An apparatus draws or leads hair and other potential entanglement debris away from the hub of a brush assembly in a vacuum as the brush rotates during vacuuming, thus avoiding or reducing entanglement and attendant problems, and obviating or reducing the need for manual removal of the entanglement. The apparatus has a profile which draws hair and other entanglement debris away from a hub of the brush assembly, or prevents it from reaching the hub, thus enabling the brush/brush assembly to continue to rotate freely. In one implementation, the apparatus attaches to a vacuum brush in an autonomous robotic vacuum.

BACKGROUND

Aspects of the present invention relate to entanglement prevention in brush assemblies in autonomous robotic vacuums.

Autonomous robotic vacuums often work in rooms on a schedule, when the user is not present. As such a vacuum traverses an environment, the vacuum picks up dirt, dust, lint, hair, and other debris and collects it in an onboard bin. In environments where substantial amounts of hair fall on the ground, brushes on board an autonomous robotic vacuum pick up the hair. Such pick up is known to cause clogging of the brush assembly, and in particular the hub on which the brush(es) is/are mounted, potentially preventing the brush(es) from rotating, and thus keeping the vacuum from operating properly. As such vacuums tend to be battery operated, the battery can run down before the vacuum finishes traversing the environment. Alternatively, if the vacuum keeps moving with the clogged brush assembly, proper cleaning cannot occur.

When the user returns, s/he may not know that there has been an entanglement. In that situation, the user may simply recharge the vacuum and set it again to operate when the user is away. However, the vacuum will not clean, because the entanglement still is there. As a result, the user will come home and find that the vacuum has not performed its intended tasks.

If the user examines the vacuum, s/he may see the entanglement. The user then has to remove the entanglement manually. However, in some circumstances the user may not see the entanglement, around the hub, very clearly. Also, even if the user does see the entanglement, it may not be easy to remove. Over time, the buildup of hair and debris could cause fatal damage to the robotic vacuum.

It would be desirable to provide an approach which avoids entanglement in the first instance.

SUMMARY OF THE INVENTION

In view of the foregoing, it is an object of the present invention to provide an apparatus which draws or leads hair and other potential entanglement debris away from the hub of a brush assembly as the brush rotates during vacuuming, thus avoiding or reducing entanglement and attendant problems, and obviating or reducing the need for manual removal of the entanglement.

In one aspect, an effect of the entanglement prevention apparatus is to enable the brush to be closer to the hub, enabling the brush to clean more effectively.

DETAILED DESCRIPTION

As now will be described in detail with respect to one or more embodiments, in one aspect the invention provides an apparatus which attaches to a vacuum brush, enabling the brush to rotate freely. The apparatus has a profile which draws hair and other entanglement debris away from a hub of the brush assembly, or prevents it from reaching the hub, thus enabling the brush/brush assembly to continue to rotate freely.

In one aspect of the invention, any number of autonomous robotic vacuums which operate with a brush assembly may employ the entanglement prevention apparatus described herein. One example of a robotic device which has vacuuming as one of its functions is described in U.S. Pat. No. 7,555,363, commonly assigned with the present application. The contents of this patent are incorporated herein by reference.

Looking atFIG. 1, an entanglement prevention apparatus100is constituted by a first endpiece110and a second endpiece160. In an embodiment, the endpieces110and160may be snapfit or otherwise attached to each other. Between the two endpieces110,160sits an insert120which is shaped to fit closely with endpiece110; a bar130providing support to insert120; a washer140; and a bushing150. In an embodiment, bar130and washer140may be press fit or otherwise attached to insert120. In an embodiment, bushing150may be press fit or otherwise attached to second endpiece160. The overall assembly of apparatus100is such that, when attached to a brush assembly as will be discussed in more detail herein, the insert120, with bar130and washer140, spins freely within the apparatus.

Each of the components of apparatus100now will be discussed in more detail. In an embodiment, first endpiece110may be generally circular in cross section, except for a tongue-shaped extension112which in some circumstances can facilitate holding the structure fast to a brush housing assembly. In an embodiment, the endpiece110may be made of plastic. Other materials which facilitate snap fitting or other attachment to second endpiece160also are possible.

Endpiece110has a first side114and a second, opposite side116. Sides114and116are sized to accommodate insert120, as now will be discussed.

In an embodiment, insert120has a generally circular portion122and an extension124which is shaped to engage with the above-mentioned brush assembly. In an embodiment, extension124may have raised portions126which facilitate firmer engagement with the brush assembly. Circular portion122has a first surface, facing extension124, with a first radius, and a second surface, on an opposite of the first surface, having a second, larger radius. In an embodiment, the progression from the first radius to the second radius is smooth and generally continuous. As a result, the circular portion122has a profile which variously may be known to ordinarily skilled artisans as a bevel, a chamfer, a taper, a slanted or angled surface, or a truncated cone. Each of these terms can have meanings which are synonymous or which are slightly different from each other. In the description herein, for convenience, the shape will be referred to as a bevel. However, this term should be understood to be shorthand for any of the several terms just mentioned, with corresponding definitions being applicable. Thus, for example, in the context of the present disclosure, something that is referred to as a chamfer will be understood also to be a bevel, a taper, a slanged or angled surface, or a truncated cone. Calling a structure one of these names does not prevent it from being known under one of the other names.

The bevel profile of circular portion122fits in a complementary fashion with a corresponding concave profile of side116of endpiece110. The fitting is such that, when endpieces110and160are mated (snap fit) to each other, insert120rotates freely within the assembly comprising endpieces110and160. Also, the profile of side114complements the shape of circular portion122. Side114′s profile, the smaller part of the bevel profile, faces the brush assembly, as will be seen. Elements130,140, and150, which will be discussed in more detail below, facilitate the free rotation of insert120.

Bar130, which in an embodiment is metal, fits in an opening in insert120. Bar130may be force fit into insert120, or otherwise may be firmly attached or adhered to insert120. In an embodiment, washer140may have an opening corresponding to that of a diameter of bar130, and may facilitate rotation of bar130within insert120.

Bushing150, which in an embodiment also is metal, has a flanged portion152and a cylindrical portion154. Cylindrical portion154may fit into an opening in second endpiece160. This fit may be a force fit or a press fit, or other kind of attachment or adherence that puts bushing securely in the second endpiece160. An end of bar130may slide into an opening in bushing150. The metal to metal contact between bar130and bushing150reduces friction, and enables the bar130to rotate freely within the bushing150. Alternatively, for example, bushing150may be made of nylon, plastic, or other material which produces relatively little friction when in contact with bar130. As another alternative, bearings may replace bushing150. As yet another alternative, bar130may be made of a material other than metal. However, where torqueing of extension124in insert120potentially is an issue, having the bar130be made of more rigid material can be desirable.

Second endpiece160may be made of a material which facilitates a press fit or a snap fit with first endpiece110. On a side opposite the side of endpiece160into which bushing150fits, there may be extensions,162,164which facilitate attachment of apparatus100into a larger structure, such as an underside of a vacuum, which in an embodiment is an autonomous robotic vacuum.

FIG. 2shows an exploded view of apparatus100in an opposite direction or orientation, so that certain portions of elements110-160are more visible. In particular, side116of first endpiece110is more visible, as is the surface on that side which complements the upper surface of circular portion122. Cylindrical mating surface118also is visible. The lip on that mating surface surrounds circular portion122as that portion nests within first endpiece110.

FIG. 2shows a hole in the middle of insert120, into which bar130fits. In an embodiment, washer140seats in the underside of insert120, and is attached so that bar130is secure within extension124of insert120. As with the previous embodiment, washer140may facilitate rotation of bar130within insert120. The other side of second endpiece160also is more visible inFIG. 2, with extensions162,164more visible.

FIG. 3shows a brush assembly300which includes brush310, apparatus100, and end cap350. In an embodiment, brush310includes bristled portions320and non-bristled portions330, for cleaning of different types of surfaces, different types of debris, and the like. In an embodiment, bristled portions320and/or non-bristled portions330are attached in serpentine fashion in brush310. Such a configuration may facilitate collection of gathered debris for direction toward a dustbin within the robotic vacuum.FIG. 3shows an embodiment in which these portions320,330are attached in a double serpentine configuration. Such a configuration also can facilitate guidance of debris toward a dustbin or other receptacle on board a robotic vacuum such as may be seen in U.S. Pat. No. 7,555,363.

InFIG. 3, apparatus100is attached to brush310as part of the overall brush assembly300. In an embodiment, extension124of insert120of apparatus100fits into an opening (not seen in this figure, but visible inFIGS. 5 and 7, for example) at the center of the brush assembly300. In an embodiment, end cap350is attached to brush310on an opposite side from apparatus100. End cap350may be configured to attach to motive structure, for example, in an autonomous robotic vacuum or other cleaning apparatus, so as to facilitate rotation of the brush assembly300by motive force. Such attachment may require a different configuration for end cap350than for apparatus100. In an embodiment, end cap350may have the same structure, configuration, and operation as apparatus100. In an embodiment, rotation of the brush may come through attachment, either directly or via some kind of gearing arrangement, to motive wheels, again as may be seen in U.S. Pat. No. 7,555,363.

FIG. 4shows a side view of brush assembly300, making it easier to see end cap350as juxtaposed with apparatus100. The double serpentine configuration of bristled and non-bristled portions320,330in an embodiment also is more apparent.

FIG. 5shows an exploded view of apparatus100as it fits into brush assembly300. As alluded to earlier, extension124of insert120fits through first endpiece110into an opening (unnumbered) in brush310so as to attach firmly within the opening, through press fit, force fit, or other manner of adherence, while enabling the subassembly comprising insert120, bar130, and washer140to continue to rotate freely through bushing150, thus enabling free rotation of brush assembly300at that end. The extensions on the side of second endpiece160may facilitate attachment of that assembly within an autonomous robotic vacuum. Such attachment will not impede free rotation of the insert120within apparatus100, however. The brush assembly opening into which extension124fits is central to the brush assembly.

FIG. 6shows a different, side view of whatFIG. 5shows, including an exploded view of apparatus100, to show how parts110-160come together and go into brush assembly300.

FIG. 7shows yet a different view of brush assembly300, with an assembled version of apparatus100and insert120juxtaposed with an opening in brush assembly300.

It has been discovered that the bevel shape of first endpiece110, into which insert120fits, tends to effectively guide hair and other potential entanglement debris away from the hub in which brush assembly300is mounted, or prevent such debris from reaching the hub in the first place. As a result, debris will not wrap around any portion of the bushing or bearing mechanism, potentially fouling it. Hair or fibers have difficulty going from a smaller diameter to a larger diameter along the bevel as the assembly rotates. The bevel creates a barrier to keep fiber or hair from impinging on the bushing or bearing, preventing clogging. The effect of this structure is to enable the brush310to be positioned more closely to the hub on which brush assembly300is mounted, enabling a longer brush which can clean more surface during a pass of the robotic device. As a result, the brush310can clean more effectively within the overall robotic vacuum structure (actually, closer to the outer edges of that structure), in part because of the brush proximity to the hub.

What has been described here is a brush assembly for use in an autonomous robotic device with various capabilities. The robotic device's autonomy is in contrast to a remote control operation of the device. Autonomy enables the robotic device to operate without supervision or external influence, for example, to clean the environment, or zones within the environment in which the robot is operating. The entanglement prevention feature described herein works well with an autonomous robotic device which may operate, for example, on a schedule when the owner/user/operator is unavailable (for example, in the case of a home robotic vacuum, away from home). Entanglement prevention means that, for example, while the owner/user/operator is unavailable, the autonomous robotic device may operate with lessened risk of non-functionality, or battery drain, or the like because of fouling or other impeding of rotation of the brush assembly.

The brush assembly, of which the entanglement prevention apparatus described herein is a part, may be part of a home robotic vacuum, but also may be configured as a cartridge which a user may select from among several types of cleaning cartridges or modules (e.g. waxers, dusters, buffers, mops, or other types of cleaners). That is, an autonomous robotic device employing a brush assembly with the entanglement prevention apparatus described herein may be configured to receive different kinds of cleaning cartridges or modules, so as to perform as a floor cleaning product which performs different types of cleaning, not just vacuuming. A non-limiting example of such a cartridge configuration again may be seen in U.S. Pat. No. 7,555,363.

Although the invention has been described in language specific to structural features and/or methodological steps, it is to be understood that the invention is not to be limited to the specific features or steps disclosed. Rather, the specific features and steps are disclosed as preferred forms of implementing the invention, which is to be defined by the claims.