CN210749025U

CN210749025U - Side sweeping and self-moving device

Info

Publication number: CN210749025U
Application number: CN201920563216.7U
Authority: CN
Inventors: 赵冰; 陆江; 李明月
Original assignee: Anker Innovations Co Ltd
Current assignee: Anker Innovations Co Ltd
Priority date: 2019-04-23
Filing date: 2019-04-23
Publication date: 2020-06-16
Anticipated expiration: 2029-04-23

Abstract

The utility model provides a limit is swept and is reached from mobile device, the limit is swept and is included: the cleaning device comprises a fixing part and at least four cleaning parts, wherein the fixing part is used for driving the cleaning parts to rotate, one end of each cleaning part is connected with the fixing part, and the other end of each cleaning part extends to the outer side of the edge of the fixing part. The utility model discloses an use four at least cleaning parts on limit sweeping, can enough guarantee the realization of limit sweeping function, can sweep the structure on the limit again and be applied to for example when sweeping the floor from the mobile device of robot, avoid sweeping the winding electric wire on the limit and appearing the dead problem of machine card when walking from the mobile device, and, sweep rotatory in-process on the limit even the brush hair scatters and can not shelter from the cliff sensor yet, thereby guarantee cliff sensor can normal work, avoided because to the cliff sensor shelter from and the appearance of the cliff problem that falls that leads to.

Description

Side sweeping and self-moving device

Technical Field

The utility model relates to a clean technical field of intelligence particularly relates to a limit is swept and is from mobile device.

Background

With the improvement of living standard of people, the application of self-moving devices (such as sweeping robots) is more and more extensive, so that the self-moving devices become necessary daily supplies in the life of people gradually. The floor sweeping robot is also called an automatic sweeper, an intelligent dust collector, a robot dust collector and the like, can automatically and autonomously complete floor sweeping work in a room by means of certain artificial intelligence, and saves time and labor for housework of people.

The bottom of the sweeping robot is usually provided with a side sweep for sweeping dust or other impurities on the ground to a suction port of the sweeping robot, and the dust or other impurities are sucked into a dust box inside the sweeping robot from the suction port. The traditional sweeping robot usually uses an edge broom with three bundles of bristles to clean corners, however, the edge broom structure is easy to wind wires when the sweeping robot walks, so that the machine is blocked, and the condition of falling off a cliff is triggered by easily shielding a cliff sensor when the bristles are scattered.

Therefore, in view of the above problems, the present invention provides a novel edge-scanning and self-moving device.

SUMMERY OF THE UTILITY MODEL

In the summary section a series of concepts in a simplified form is introduced, which will be described in further detail in the detailed description section. The inventive content does not imply any attempt to define the essential features and essential features of the claimed solution, nor is it implied to be intended to define the scope of the claimed solution.

Not enough to prior art, the utility model provides a limit is swept, limit is swept and is included:

the cleaning device comprises a fixing part and at least four cleaning parts, wherein the fixing part is used for driving the cleaning parts to rotate, one end of each cleaning part is connected with the fixing part, and the other end of each cleaning part extends to the outer side of the edge of the fixing part.

Illustratively, the at least four cleaning parts are distributed around the edge of the fixing part at equal intervals.

For example, when the edge brush is mounted on the self-moving device, a distance from an end of each of the cleaning portions located outside the fixed portion to a center of the fixed portion is smaller than a distance from a cliff sensor of the self-moving device to the center of the fixed portion.

For example, when the edge broom is mounted on the self-moving device, a distance from an end of the at least four cleaning parts located outside the fixed part to a center of the fixed part is greater than or equal to a distance from a cliff sensor of the self-moving device to the center of the fixed part.

Exemplarily, the partial cleaning portion is one cleaning portion of the at least four cleaning portions.

Illustratively, the number of the at least four sweeping parts is 12.

Illustratively, each of the sweeping parts includes bristles connected to the fixing part.

Illustratively, bristles of at least some of the at least four sweeping parts are coated with soft gel.

Illustratively, the soft gel coats a partial length of the bristles adjacent the anchor.

The utility model discloses another aspect provides a from mobile device, from mobile device includes:

a housing;

at least one of the aforementioned edge sweeps, the edge sweeps being rotatably disposed at the bottom of the housing;

at least one cliff sensor disposed at a bottom of the housing.

The utility model discloses a limit is swept including fixed part and four at least cleaning parts, the fixed part is used for driving the cleaning part rotates, the one end of cleaning part is connected the fixed part, the other end extends to the edge outside of fixed part uses four at least cleaning parts can enough guarantee the realization of limit sweeping the function, can sweep the structure on the limit again and be applied to for example when sweeping the self-moving device of robot, avoids sweeping the winding electric wire when walking from the self-moving device and appearing the dead problem of machine card on the limit to, sweep rotatory in-process on the limit and also can not shelter from cliff sensor even the brush hair scatters, thereby guarantee that cliff sensor can normally work, avoided because to the appearance of falling cliff problem that leads to sheltering from of cliff sensor.

Drawings

The following drawings of the present invention are used herein as part of the present invention for understanding the present invention. There are shown in the drawings, embodiments and descriptions of the invention, which are used to explain the principles of the invention.

In the drawings:

fig. 1 illustrates a bottom view of a self-moving device according to an embodiment of the present invention;

FIG. 2 shows a schematic view of a side sweep of an embodiment of the present invention;

figure 3 shows a schematic view of the edge scan rotational coverage of an embodiment of the present invention.

The reference numerals are explained below:

steering wheel 102 of bottom case 101

Edge broom 103 fixing part 1031

Cleaning part 1032

First drive wheel assembly 1041 second drive wheel assembly 1042

Cliff sensor 105 cliff sensor's transmitter 1051

Cliff sensor receiver 1052 edge sweep rotational coverage 106

Detailed Description

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the present invention.

It is to be understood that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. Like reference numerals refer to like elements throughout.

It will be understood that when an element or layer is referred to as being "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it can be directly on, adjacent to, connected or coupled to the other elements or layers or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly adjacent to," "directly connected to" or "directly coupled to" other elements or layers, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.

Spatial relational terms such as "under," "below," "under," "above," "over," and the like may be used herein for convenience in describing the relationship of one element or feature to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, then elements or features described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary terms "under" and "under" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of the associated listed items.

In order to thoroughly understand the present invention, a detailed structure will be provided in the following description in order to explain the technical solution provided by the present invention. The preferred embodiments of the present invention are described in detail below, however, other embodiments of the present invention are possible in addition to these detailed descriptions.

Next, the edge-scanning and self-moving device in the embodiment of the present invention will be described in detail with reference to the accompanying drawings, wherein fig. 1 shows a bottom view of the self-moving device according to an embodiment of the present invention; FIG. 2 shows a schematic view of a side sweep of an embodiment of the present invention; figure 3 shows a schematic view of the edge scan rotational coverage of an embodiment of the present invention.

It should be noted that, in the present embodiment, the new scheme is mainly explained and explained by taking the case that the self-moving device is a sweeping robot as an example, but those skilled in the art can understand that the self-moving device is not limited to the sweeping robot, and may be other devices such as a dust collector, etc.

As an example, as shown in fig. 1, the self-moving device 100 includes a housing, wherein the housing has a cavity (not shown) therein, and the housing includes a bottom case 101 and a top case, wherein the bottom case and the top case are combined into a housing of the entire self-moving device.

The bottom case 101 and the top case may be combined by means of a snap or a fastening connection by means of a fastener (e.g., a screw, a bolt), wherein the bottom case 101 and the top case have a cavity therebetween for accommodating various components of the self-moving apparatus.

The bottom case 101 may be integrally formed of a material such as plastic, which includes a plurality of preformed grooves, recesses, or structural members for mounting or integrating various components of the self-moving device on the bottom case 101.

In some embodiments, the top case may also be integrally molded from a material such as plastic and configured to complement bottom case 101 and provide protection for various components mounted to the bottom case 101. The bottom case 101 and the top case may be removably combined together by various suitable fasteners (e.g., screws, bolts), and after being combined together, the bottom case 101 and the top case form a low-height enclosure having a generally cylindrical configuration that is generally symmetrical along its front-to-rear axis, or other suitably shaped symmetrical configuration.

In one embodiment, the self-moving device further comprises a steering wheel 102 disposed below the housing, wherein the steering wheel 102 comprises a rotating shaft disposed in a vertical direction. The steering wheel can rotate in a horizontal 360-degree range around a rotating shaft.

Illustratively, a groove (not shown) for accommodating the steering wheel 102 is provided at the bottom of the bottom case 101, and at least a part of the wheel body of the steering wheel protrudes outward from the bottom of the bottom case 101 when the steering wheel 102 is attached to the bottom case 101.

The steerable wheel 102 may be, for example, a universal wheel, or other suitable steerable wheel configuration. Illustratively, the steering wheel 102 includes a wheel body and a base. The steering wheel 102 is located at one end of the front-to-back diameter of the self-moving device, such as a sweeping robot.

A groove is provided on the bottom of the bottom case 101 of the self-moving device, the base is mounted in the groove and can rotate on a horizontal plane parallel to the bottom surface of the base, and the wheel is mounted on the base and can rotate on a vertical plane perpendicular to the horizontal plane. The base has a generally circular configuration with a wheel eccentrically mounted on the circular base. For example, the base includes a sloped surface that is sloped with respect to a bottom surface of the base and adjacent to the wheel such that during sweeping, the sloped surface is forward of the wheel to reduce the resistance of the wheel to movement from the mobile device.

In some embodiments, the inclined surface of the base is inclined at 5 ° to 30 °, such as 10 °, 15 °, 20 °, and so on, with respect to the bottom surface of the bottom case 101. In some embodiments, the wheel is located 0.3-3 cm below the bottom surface of the bottom case 101, for example, the lowest end of the wheel is 0.5 cm, 1 cm, 2 cm, etc. below the bottom surface of the bottom case 101.

Although in the above described embodiments the self-moving device, e.g. the sweeping robot, has only one steerable wheel, in other embodiments the sweeping robot may have two or more steerable wheels. For example, the sweeping robot may have first and second steerable wheels located at one end of the front-to-back diameter of the sweeping robot and spaced apart from each other.

In one example, the self-moving device further includes a first drive wheel assembly 1041 and a second drive wheel assembly 1042, each having a respective independently operated motor.

The first and second

drive wheel assemblies

1041 and 1042 are independently mounted in recesses at opposite ends of a bottom lateral diameter of the bottom housing 101 that is perpendicular to the front-to-rear diameter on which the steerable wheels are typically disposed. Since the two drive wheel assemblies are driven by independent motors, a wider range of steering maneuvers can be provided for the self-propelled device, e.g., sharp turns, gradual turns, pivot turns, and the like. Installing two drive wheel subassemblies at the both ends of horizontal diameter provides stronger steering ability for sweeping robot.

It should be noted that, during the cleaning, all of the bottom ends of the plurality of wheels of the sweeping robot, including the steering wheel, the first driving wheel assembly and the second driving wheel assembly, reach the plane parallel to the bottom surface of the movable key, so that the sweeping robot runs stably.

By way of example, the self-moving device 100 also includes a user interface that may be disposed on a top case or a sidewall of the self-moving device to receive one or more user commands and/or to display a current state of the self-moving device. The user interface is capable of communicating with the controller such that one or more user commands received by the user interface can cause a self-moving device, such as a sweeping robot, to perform a routine, such as a cleaning.

In one example, the self-moving device further comprises a sweeping system for sweeping or treating the floor surface. The purging system may be a dry purging system or a wet purging system.

As an example, as shown in fig. 1, the main cleaning function of the dry cleaning system is derived from a sweeping system consisting of a rolling brush structure, a dust box structure, a fan structure, an air outlet and connecting parts among the four. The rolling brush structure with certain interference with the ground sweeps the garbage on the ground and winds the garbage to the front of a dust suction opening between the rolling brush structure and the dust box structure, and then the garbage is sucked into the dust box structure by the air with suction generated by the fan structure and passing through the dust box structure.

The dust removal capacity of the self-moving device can be represented by the cleaning efficiency DPU (dust pick up efficiency) of the garbage, and the cleaning efficiency DPU is influenced by the structure and the material of the rolling brush, the wind power utilization rate of an air duct formed by a dust suction port, a dust box structure, a fan structure, an air outlet and connecting parts among the dust suction port, the dust box structure, the fan structure, the air outlet and the dust box structure, and the type and the power of the fan.

The dry sweeping system may also include a side sweep 103 having an axis of rotation that is angled relative to the ground for moving debris into the rolling brush area of the sweeping system. Optionally, the self-moving device 100 comprises at least one side sweep 103, for example two side sweeps 103, the two side sweeps 103 being arranged on both sides of the steering wheel 102, in particular at the front end of the housing. The self-moving apparatus further includes a side-sweep motor (not shown) for controlling the rotation of the side-sweep 103.

The edge brush 103 has an end portion located outside the side wall of the mobile device case, that is, a partial area to be cleaned by the edge brush is located outside the edge of the smart mobile outermost periphery, so that the partial area located outside the mobile device case can be cleaned by the edge brush, and thus an area closer to a wall surface or the like can be cleaned.

The self-moving device further includes a plurality of sensors for sensing the surrounding environment, such as a position determining device (not shown) located above the housing, a bumper located at a forward portion of the housing, a cliff sensor and an ultrasonic sensor (not shown), an infrared sensor (not shown), a magnetometer (not shown), an accelerometer (not shown), a gyroscope (not shown), an odometer (not shown), and the like, for providing various position information and motion state information of the self-moving device to the control system.

In one example, as shown in fig. 1, the self-moving apparatus 100 further includes at least one cliff sensor 105, for example, two cliff sensors 105, provided on the bottom of the housing, and the cliff sensor 105 is a sensor for detecting a cliff (a hole, a cliff, or the like) that is a place where the ground does not exist by detecting whether the ground exists around. The self-moving apparatus 100 can be prevented from falling from a high platform such as a table by providing a cliff sensor.

Alternatively, the cliff sensors 105 are disposed at the edge of the bottom case 101, preferably in an even number, and may be symmetrically disposed to detect whether there is an object under the sensors to prevent the object from falling from the mobile device 100.

Cliff sensor 105 may be an optical sensor, such as an infrared sensor, disposed at the bottom of the housing (e.g., on bottom case 101), cliff sensor 105 may include a transmitter 1051 and a receiver 1052, such as transmitter 1051 for transmitting a sensing signal (e.g., infrared light) and receiver 1052 for receiving the sensing signal reflected back by the object to provide distance feedback to control movement of the self-moving device, which may prevent the self-moving device from falling off a high platform, such as a table. In addition to optical sensors, cliff sensors 105 may also be mechanical or ultrasonic sensors.

The cliff sensors 105 are located at the front bottom of the self-moving device 100, are even in number, and are arranged in bilateral symmetry to detect whether there is an object below the sensors, so as to prevent the self-moving device 100 from falling.

The self-moving device also comprises a control system which is arranged on a circuit main board of the self-moving device and comprises a non-transitory memory, such as a hard disk, a flash memory and a random access memory, and a communication computing processor, such as a central processing unit and an application processor. The control system includes a processor, a microprocessor, or the like, and further includes a control circuit electrically connected to the cliff sensor, the processor, or the like, and the control system may control the self-moving device to maintain a moving state when the cliff sensor detects the presence of an object below the self-moving device, and to stop moving, turning, or the like to prevent the self-moving device from falling when the cliff sensor detects the absence of an object below the self-moving device.

The position of the side broom 103 is adjacent to the cliff sensor 105, in order to solve the problem that the side broom currently used for sweeping winds the electric wire and shields the cliff sensor, as shown in fig. 2 and 3, the embodiment of the present invention provides a side broom 103, the side broom comprises a fixing part 1031 and at least four cleaning parts 1032, the fixing part 1031 is used for driving the cleaning parts 1032 to rotate, one end of the cleaning parts 1032 is connected with the fixing part 1031, and the other end extends to the outer side of the edge of the fixing part 1031.

The fixing part 1031 is used for driving the cleaning part to rotate, wherein the self-moving device includes a rotating shaft, one end of the rotating shaft is connected to the edge-cleaning motor, the other end of the rotating shaft is connected to the fixing part, the connection may be a fixed connection, or a detachable connection, for example, the fixing part may be connected to one end of the rotating shaft by a screw or other connecting members.

The fixing part 1031 may be, for example, circular or other suitable shape, and the axis of the rotating shaft is perpendicular to the fixing part 1031, and the axis of the rotating shaft serves as a sweeping rotation axis, and the rotation axis may be perpendicular to the bottom surface of the housing. The edge-sweeping motor drives the rotation shaft to rotate, thereby driving the fixing part 1031 to rotate, and the fixing part 1031 drives the cleaning part 1032 to rotate, so as to perform cleaning.

The at least four cleaning parts 1032 can be arranged around the fixing part in any suitable arrangement, for example, as shown in fig. 2, the at least four cleaning parts 1032 are equally spaced from each other around the edge of the fixing part 1031, for example, adjacent cleaning parts 1032 have the same included angle therebetween. In one example, each of the cleaning portions 1032 extends a partial length in a radial direction from the stationary portion.

In one example, when the side broom 103 has two first cleaning parts, the two first cleaning parts are spaced apart, for example, at equal intervals, around the outer circumference of the fixing part 1031.

The number of the at least four cleaning portions 1032 may be any number from 4 to 8, any number from 4 to 12, or any number from 6 to 12, wherein optionally the number of the at least four cleaning portions is 12. The 12 cleaning parts (such as bristles) are distributed at equal intervals, namely symmetrically, so that the problem that the machine is blocked when the self-moving device walks while sweeping and winding electric wires can be effectively avoided, and the cliff sensor cannot be shielded. Fig. 3 shows a schematic view of the side-scan rotation coverage 106 according to an embodiment of the present invention, and it can be seen from the figure that the side-scan rotation coverage 106 does not block the region where the cliff sensor 105 is located, and particularly does not block the receiver 1052 of the cliff sensor, so as to ensure the normal operation of the cliff sensor.

The length of the cleaning parts 1032 can be set appropriately according to actual needs, and each cleaning part can have the same length or different lengths, for example, when the side broom 103 is mounted on the mobile device, the distance from the end of each cleaning part 1032 located outside the fastening part 1031 to the center of the fastening part 1031 is smaller than the distance from the cliff sensor 105 of the mobile device to the center of the fastening part 1031, particularly smaller than the distance from the receiver 1052 of the cliff sensor to the center of the fastening part 1031, or when the side broom is mounted on the mobile device, the distance from the end of each cleaning part located outside the fastening part to the center of the fastening part is greater than or equal to the distance from the cliff sensor of the mobile device to the center of the fastening part, for example, one cleaning part of the at least four cleaning parts is greater than or equal to the distance from the cliff sensor of the mobile device to the center of the fastening part However, in any case, it is necessary to ensure that the end of the cleaning part 1032 of the side broom 103 remote from the attachment part is positioned outside the side wall of the case of the self-moving device, that is, the cleaning part 1032 of a certain length is positioned outside the edge of the outermost periphery of the self-moving device during the rotation of the side broom, so that the side broom can clean a part of the area positioned outside the case of the self-moving device, and can clean an area closer to the wall surface, and the like, thereby preventing the existence of a dead space. Moreover, even if a part of the cleaning part shields the cliff sensor, the normal operation of the cliff sensor is not influenced, and the length of the part of the cleaning part is longer, so that the cleaning is more favorable for cleaning an area close to a wall surface and the like, and the cleaning dead angle is prevented.

Optionally, each of the cleaning parts 1032 includes bristles connected to the fixing part 1031. The bristles of the cleaning part 1032 may be any suitable bristles, for example, a bundle of bristles consisting of a plurality of strip-shaped bristles, and only one bundle of bristles is mounted on each cleaning part 1032. Alternatively, the bristles may be replaced by other cleaning elements having a cleaning function, such as strips of adhesive or other flexible strips.

In one example, the bristles of at least some of the at least four sweeps 1032 are coated with a soft gel (not shown), e.g., the bristles of each sweep 1032 are coated with a soft gel. Optionally, the soft gel coats at least a portion of the length of the bristles. For example, the soft gel covers all of the bristles, or the soft gel covers part of the length of the bristles, and particularly, the soft gel covers part of the length of the bristles adjacent to the fixing part.

Because the soft rubber material has certain toughness and elasticity, the bristles cannot be easily broken even if a harder object is swept in the sweeping and rotating process. In addition, because the flexible glue material is flexible material, consequently clean the in-process on ground, the degree of wear is less between flexible glue and the ground to avoid fish tail ground.

To sum up, the utility model discloses an limit is swept including fixed part and four at least cleaning parts, the fixed part is used for driving the cleaning part rotates, the one end of cleaning part is connected the fixed part, the other end extends to the edge outside of fixed part uses four at least cleaning parts can enough guarantee the limit to sweep the realization of sweeping the function, can sweep the structure on the limit again and be applied to for example when sweeping the self-moving device of robot, avoids sweeping the winding electric wire when walking from the self-moving device and appearing the dead problem of machine card on the limit to, sweep rotatory in-process even the brush hair scatters on the limit and also can not shelter from cliff sensor, thereby guarantee that cliff sensor can normally work, avoided because to the appearance of falling cliff problem that leads to sheltering from of cliff sensor.

In addition, the self-moving device of the embodiment of the application has the advantages due to the edge sweeping.

The present invention has been described in terms of the above embodiments, but it is to be understood that the above embodiments are for purposes of illustration and description only and are not intended to limit the invention to the described embodiments. Furthermore, it will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that many more modifications and variations are possible in light of the teaching of the present invention and are within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. An edge brush, comprising:

2. The edge brush as claimed in claim 1, wherein the at least four sweeping portions are equally spaced from each other around the edge of the fixed portion.

3. The edge broom of claim 1, wherein when the edge broom is mounted on a self-moving device, a distance from an end of each cleaning portion located outside the fixed portion to a center of the fixed portion is smaller than a distance from a cliff sensor of the self-moving device to the center of the fixed portion.

4. The edge brush as claimed in claim 1, wherein when the edge brush is mounted on the self-moving device, a distance from an end of the at least four cleaning parts located outside the fixed part to a center of the fixed part is greater than or equal to a distance from a cliff sensor of the self-moving device to the center of the fixed part.

5. The edge broom of claim 4, wherein the partial sweep is one of the at least four sweeps.

6. The edge broom of claim 1, wherein the at least four sweeping portions are 12 in number.

7. The edge brush as claimed in claim 1, wherein each of the sweeping parts includes bristles connected to the fixing part.

8. The edge broom of claim 7, wherein bristles of at least some of the at least four sweeping portions are coated with soft gel.

9. The edge broom of claim 8, wherein the soft gel coats a partial length of the bristles adjacent the anchor portion.

10. A self-moving apparatus, comprising:

a housing;

at least one sweeper according to any one of claims 1 to 9 rotatably disposed at the bottom of the housing;

at least one cliff sensor disposed at a bottom of the housing.