Abstract:
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.

Description:
[0001]    The present application claims the benefit of U.S. Provisional Patent Application No. 62/167,818, filed May 28, 2015, incorporated by reference in its entirety herein. 
     
    
     BACKGROUND 
       [0002]    Aspects of the present invention relate to entanglement prevention in brush assemblies in autonomous robotic vacuums. 
         [0003]    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. 
         [0004]    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. 
         [0005]    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. 
         [0006]    It would be desirable to provide an approach which avoids entanglement in the first instance. 
       SUMMARY OF THE INVENTION 
       [0007]    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. 
         [0008]    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. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is an exploded view of an entanglement prevention apparatus in accordance with one aspect of the invention. 
           [0010]      FIG. 2  is another exploded view of an entanglement prevention apparatus in accordance with one aspect of the invention. 
           [0011]      FIG. 3  is another view of an entanglement prevention apparatus, as related to a brush assembly, in accordance with one aspect of the invention. 
           [0012]      FIG. 4  is yet another view of an entanglement prevention apparatus, as related to a brush assembly, in accordance with one aspect of the invention. 
           [0013]      FIG. 5  is an exploded view of an entanglement prevention apparatus, as related to a brush assembly, in accordance with one aspect of the invention. 
           [0014]      FIG. 6  is another exploded view of an entanglement prevention apparatus, as related to a brush assembly, in accordance with one aspect of the invention. 
           [0015]      FIG. 7  is yet another exploded view of an entanglement prevention apparatus, as related to a brush assembly, in accordance with one aspect of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    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. 
         [0017]    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. 
         [0018]    Looking at  FIG. 1 , an entanglement prevention apparatus  100  is constituted by a first endpiece  110  and a second endpiece  160 . In an embodiment, the endpieces  110  and  160  may be snapfit or otherwise attached to each other. Between the two endpieces  110 ,  160  sits an insert  120  which is shaped to fit closely with endpiece  110 ; a bar  130  providing support to insert  120 ; a washer  140 ; and a bushing  150 . In an embodiment, bar  130  and washer  140  may be press fit or otherwise attached to insert  120 . In an embodiment, bushing  150  may be press fit or otherwise attached to second endpiece  160 . The overall assembly of apparatus  100  is such that, when attached to a brush assembly as will be discussed in more detail herein, the insert  120 , with bar  130  and washer  140 , spins freely within the apparatus. 
         [0019]    Each of the components of apparatus  100  now will be discussed in more detail. In an embodiment, first endpiece  110  may be generally circular in cross section, except for a tongue-shaped extension  112  which in some circumstances can facilitate holding the structure fast to a brush housing assembly. In an embodiment, the endpiece  110  may be made of plastic. Other materials which facilitate snap fitting or other attachment to second endpiece  160  also are possible. 
         [0020]    Endpiece  110  has a first side  114  and a second, opposite side  116 . Sides  114  and  116  are sized to accommodate insert  120 , as now will be discussed. 
         [0021]    In an embodiment, insert  120  has a generally circular portion  122  and an extension  124  which is shaped to engage with the above-mentioned brush assembly. In an embodiment, extension  124  may have raised portions  126  which facilitate firmer engagement with the brush assembly. Circular portion  122  has a first surface, facing extension  124 , 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 portion  122  has 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. 
         [0022]    The bevel profile of circular portion  122  fits in a complementary fashion with a corresponding concave profile of side  116  of endpiece  110 . The fitting is such that, when endpieces  110  and  160  are mated (snap fit) to each other, insert  120  rotates freely within the assembly comprising endpieces  110  and  160 . Also, the profile of side  114  complements the shape of circular portion  122 . Side  114 ′s profile, the smaller part of the bevel profile, faces the brush assembly, as will be seen. Elements  130 ,  140 , and  150 , which will be discussed in more detail below, facilitate the free rotation of insert  120 . 
         [0023]    Bar  130 , which in an embodiment is metal, fits in an opening in insert  120 . Bar  130  may be force fit into insert  120 , or otherwise may be firmly attached or adhered to insert  120 . In an embodiment, washer  140  may have an opening corresponding to that of a diameter of bar  130 , and may facilitate rotation of bar  130  within insert  120 . 
         [0024]    Bushing  150 , which in an embodiment also is metal, has a flanged portion  152  and a cylindrical portion  154 . Cylindrical portion  154  may fit into an opening in second endpiece  160 . 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 endpiece  160 . An end of bar  130  may slide into an opening in bushing  150 . The metal to metal contact between bar  130  and bushing  150  reduces friction, and enables the bar  130  to rotate freely within the bushing  150 . Alternatively, for example, bushing  150  may be made of nylon, plastic, or other material which produces relatively little friction when in contact with bar  130 . As another alternative, bearings may replace bushing  150 . As yet another alternative, bar  130  may be made of a material other than metal. However, where torqueing of extension  124  in insert  120  potentially is an issue, having the bar  130  be made of more rigid material can be desirable. 
         [0025]    Second endpiece  160  may be made of a material which facilitates a press fit or a snap fit with first endpiece  110 . On a side opposite the side of endpiece  160  into which bushing  150  fits, there may be extensions,  162 ,  164  which facilitate attachment of apparatus  100  into a larger structure, such as an underside of a vacuum, which in an embodiment is an autonomous robotic vacuum. 
         [0026]      FIG. 2  shows an exploded view of apparatus  100  in an opposite direction or orientation, so that certain portions of elements  110 - 160  are more visible. In particular, side  116  of first endpiece  110  is more visible, as is the surface on that side which complements the upper surface of circular portion  122 . Cylindrical mating surface  118  also is visible. The lip on that mating surface surrounds circular portion  122  as that portion nests within first endpiece  110 . 
         [0027]      FIG. 2  shows a hole in the middle of insert  120 , into which bar  130  fits. In an embodiment, washer  140  seats in the underside of insert  120 , and is attached so that bar  130  is secure within extension  124  of insert  120 . As with the previous embodiment, washer  140  may facilitate rotation of bar  130  within insert  120 . The other side of second endpiece  160  also is more visible in  FIG. 2 , with extensions  162 ,  164  more visible. 
         [0028]      FIG. 3  shows a brush assembly  300  which includes brush  310 , apparatus  100 , and end cap  350 . In an embodiment, brush  310  includes bristled portions  320  and non-bristled portions  330 , for cleaning of different types of surfaces, different types of debris, and the like. In an embodiment, bristled portions  320  and/or non-bristled portions  330  are attached in serpentine fashion in brush  310 . Such a configuration may facilitate collection of gathered debris for direction toward a dustbin within the robotic vacuum.  FIG. 3  shows an embodiment in which these portions  320 ,  330  are 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. 
         [0029]    In  FIG. 3 , apparatus  100  is attached to brush  310  as part of the overall brush assembly  300 . In an embodiment, extension  124  of insert  120  of apparatus  100  fits into an opening (not seen in this figure, but visible in  FIGS. 5 and 7 , for example) at the center of the brush assembly  300 . In an embodiment, end cap  350  is attached to brush  310  on an opposite side from apparatus  100 . End cap  350  may 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 assembly  300  by motive force. Such attachment may require a different configuration for end cap  350  than for apparatus  100 . In an embodiment, end cap  350  may have the same structure, configuration, and operation as apparatus  100 . 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. 
         [0030]      FIG. 4  shows a side view of brush assembly  300 , making it easier to see end cap  350  as juxtaposed with apparatus  100 . The double serpentine configuration of bristled and non-bristled portions  320 ,  330  in an embodiment also is more apparent. 
         [0031]      FIG. 5  shows an exploded view of apparatus  100  as it fits into brush assembly  300 . As alluded to earlier, extension  124  of insert  120  fits through first endpiece  110  into an opening (unnumbered) in brush  310  so as to attach firmly within the opening, through press fit, force fit, or other manner of adherence, while enabling the subassembly comprising insert  120 , bar  130 , and washer  140  to continue to rotate freely through bushing  150 , thus enabling free rotation of brush assembly  300  at that end. The extensions on the side of second endpiece  160  may facilitate attachment of that assembly within an autonomous robotic vacuum. Such attachment will not impede free rotation of the insert  120  within apparatus  100 , however. The brush assembly opening into which extension  124  fits is central to the brush assembly. 
         [0032]      FIG. 6  shows a different, side view of what  FIG. 5  shows, including an exploded view of apparatus  100 , to show how parts  110 - 160  come together and go into brush assembly  300 . 
         [0033]      FIG. 7  shows yet a different view of brush assembly  300 , with an assembled version of apparatus  100  and insert  120  juxtaposed with an opening in brush assembly  300 . 
         [0034]    It has been discovered that the bevel shape of first endpiece  110 , into which insert  120  fits, tends to effectively guide hair and other potential entanglement debris away from the hub in which brush assembly  300  is 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 brush  310  to be positioned more closely to the hub on which brush assembly  300  is mounted, enabling a longer brush which can clean more surface during a pass of the robotic device. As a result, the brush  310  can 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. 
         [0035]    What has been described here is a brush assembly for use in an autonomous robotic device with various capabilities. The robotic device&#39;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. 
         [0036]    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. 
         [0037]    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.