Patent Description:
Embodiments of the present disclosure relates to autonomous ground working vehicles and, more particularly, to an autonomous mower.

Lawn and garden machines are known for performing a variety of tasks. For instance, powered lawn mowers are used by both homeowners and professionals alike to maintain turf areas within a property or yard.

Mowers that autonomously perform a grass cutting function are also known. Autonomous mowers typically have a deck or housing supporting one or more cutting blades. Battery-powered electric motors can power both the cutting blade(s) and a propulsion system.

As with conventional mowers, it can be beneficial to adjust the height of cut provided by the mower. For example, lawn conditions and/or homeowner preferences can benefit from cutting the grass at one of several different heights.

<CIT> discloses a lawn mower robot, including an inner body, an outer cover configured to surround an outer-side of the inner body, wheels rotatably mounted at both sides of the inner body, respectively, a rotating plate rotatably mounted on a bottom surface of the inner body and disposed be inclined downward with respect to a horizontal plane in a travelling direction of the inner body, a plurality of blades coupled to an edge portion of the rotating plate to be unfolded in a centrifugal direction and folded in the direction of the center of the circle and spaced apart from each other in a circumferential direction of the rotating plate to cut grass while rotating around the rotating shaft of the rotating plate, and a blade protection cover formed to be spaced apart from the blades to prevent a fragment of an obstacle from being thrown out of the cover due to collision with the blades, wherein the blade has a cross-sectional shape of a parallelogram and is formed of a plate having a predetermined width in a longitudinal direction.

The above summary is not intended to describe each embodiment or every implementation. Rather, a more complete understanding of illustrative embodiments will become apparent and appreciated by reference to the following Detailed Description of Exemplary Embodiments and claims in view of the accompanying figures of the drawing.

Exemplary embodiments will be further described with reference to the figures of the drawing, wherein:.

The figures are rendered primarily for clarity and, as a result, are not necessarily drawn to scale. Moreover, various structure/components, including but not limited to fasteners, electrical components (wiring, cables, etc.), and the like, can be shown diagrammatically or removed from some or all of the views to better illustrate aspects of the depicted embodiments, or where inclusion of such structure/components is not necessary to an understanding of the various exemplary embodiments described herein. The lack of illustration/description of such structure/components in a particular figure is, however, not to be interpreted as limiting the scope of the various embodiments in any way.

In the following detailed description of illustrative embodiments, reference is made to the accompanying figures of the drawing which form a part hereof. It is to be understood that other embodiments, which cannot be described and/or illustrated herein, are certainly contemplated.

All headings provided herein are for the convenience of the reader and should not be used to limit the meaning of any text that follows the heading, unless so specified. Moreover, unless otherwise indicated, all numbers expressing quantities, and all terms expressing direction/orientation (e.g., vertical, horizontal, parallel, perpendicular, etc.) in the specification and claims are to be understood as being modified in all instances by the term "about. " Further, the term "and/or" (if used) means one or all of the listed elements or a combination of any two or more of the listed elements. Still further, "i.e." can be used herein as an abbreviation for the Latin phrase id est, and means "that is," while "e.g.," can be used as an abbreviation for the Latin phrase exempli gratia and means "for example.

Embodiments of the present disclosure are directed to autonomous ground working vehicles operable within a predefined work region (e.g., a turf area of a residential or commercial property). Such vehicles have a tool and operate the tool autonomously within the work region. For example, the vehicle can be configured as an autonomous lawn mower adapted to cut grass as the mower travels over the work region. Vehicles in accordance with embodiments of the present disclosure thus have a tool (e.g., cutting blade) control system formed by a tool (e.g., blade) drive system and a tool (e.g., blade) height adjustment (e.g., height-of-cut (HOC)) control system. The HOC control system can allow the mower to automatically change the height of cut grass, and/or can permit the operator to adjust the height of cut via commands issued from a remote computer (e.g., desktop computer, tablet, smart phone) or dedicated local (attached to the mower) interface. Moreover, HOC control systems in accordance with embodiments of the present disclosure can be manufactured in a cost-effective manner while still providing consistent transition between different heights-of-cut (i.e., height-of-cut changes can occur with little or minimal binding or chatter).

While the "tool" is described herein as cutting blade for a lawn mower, such a configuration is exemplary only as systems and methods described herein can also find application to other autonomously operated vehicles incorporating other tools including, for example, commercial turf products, other ground working vehicles (e.g., debris blowers/vacuums, aerators, material spreaders, snow throwers), as well as indoor working vehicles such as vacuums and floor scrubbers/cleaners.

It is noted that the term "comprises" and variations thereof do not have a limiting meaning where these terms appear in the accompanying description and claims. Further, "a," "an," "the," "at least one," and "one or more" are used interchangeably herein. Moreover, relative terms such as "left," "right," "front," "fore," "forward," "rear," "aft," "rearward," "top," "bottom," "side," "upper," "lower," "above," "below," "horizontal," "vertical," and the like can be used herein and, if so, are from the perspective shown in the particular figure, or while the vehicle (e.g., mower <NUM>) is operating upon a ground surface <NUM> as shown in <FIG>. These terms are used only to simplify the description, however, and not to limit the interpretation of any embodiment described.

Still further, the suffixes "a" and "b" can be used throughout this description to denote various left- and right- side parts/features, respectively. However, in most pertinent respects, the parts/features denoted with "a" and "b" suffixes are substantially identical to, or mirror images of, one another. It is understood that, unless otherwise noted, the description of an individual part/feature (e.g., part/feature identified with an "a" suffix) also applies to the opposing part/feature (e.g., part/feature identified with a "b" suffix). Similarly, the description of a part/feature identified with no suffix can apply, unless noted otherwise, to both the corresponding left and right part/feature.

<FIG> and <FIG> illustrate a perspective view and side elevation view, respectively, of an exemplary working vehicle, e.g., autonomous lawn mower <NUM>, in accordance with embodiments of the present disclosure. The mower <NUM> has a mower housing or deck <NUM> (including a chassis <NUM>; see <FIG>) supported in rolling engagement upon a ground surface <NUM> by two or more ground-engaging wheels. For example, rear wheels <NUM> (e.g., rear wheels 106a, 106b) and front wheels <NUM> (e.g., front wheels 108a, 108b; see <FIG>) can be attached, respectively, at or near the rear and front sides of the deck <NUM> as shown. The wheels can rotate, relative to the deck <NUM>, as the deck translates over the ground surface <NUM>. Some of the wheels can be powered to propel the mower during operation. For example, the rear wheels <NUM> can be independently driven in forward and reverse directions, while the front wheels can passively caster. As a result, differential rotation of the rear wheels <NUM> can affect both forward and reverse propulsion as well as steering of the mower <NUM>.

As shown in <FIG> and <FIG>, the deck <NUM> can have a chassis <NUM> adapted to support various components of the mower. The chassis <NUM> is coupled to the wheels <NUM>, <NUM> and can be coupled to corresponding drive wheel motors <NUM>, radio <NUM>, a battery(s) <NUM>, a cutting assembly <NUM>, and a controller <NUM> among other components. The deck <NUM> can have a chassis cover <NUM> adapted to at least partially seal or otherwise protect various components of the mower <NUM> and chassis <NUM>. The deck <NUM> can have a bump shroud <NUM> that forms an outer body of the mower <NUM>.

The bump shroud <NUM> can form a plurality of sidewalls (e.g., left and right sidewalls <NUM> (e.g., left sidewall 103b, right sidewall 103a), front sidewall <NUM>, and rear sidewall <NUM>) that partially enclose the chassis <NUM>. In particular, the bump shroud at least partially encloses an upper portion of the chassis <NUM> and the chassis cover <NUM>. A cutting chamber <NUM> is defined under the chassis <NUM>. In some embodiments the bump shroud surrounds a portion of the cutting chamber <NUM>. In some embodiments, the sidewalls can be configured to detect contact of the moving mower <NUM> with obstacles. Moreover, the left and right sidewalls <NUM> can extend outwardly to or beyond the rear wheel track width to effectively form trim edges of the mower during operation. The bump shroud <NUM> can have a roof portion <NUM> that defines the top side of the mower <NUM>, where the roof portion <NUM> is coupled to each of the plurality of sidewalls <NUM>, <NUM>, <NUM>.

The roof portion <NUM> can have one or more access openings <NUM>, <NUM> to provide user access to a control panel <NUM> (<FIG>) and/or manually operable adjustment features (which will be described in more detail below). In some embodiments, an access opening <NUM>, <NUM> can have a manually openable cover that selectively provides access to a control panel or other adjustment features. In some embodiments, a control panel can be disposed across an access opening <NUM>, <NUM> and in other embodiments, an access opening <NUM>, <NUM> can be omitted and a control panel can be disposed on the roof portion <NUM>.

<FIG> depicts a perspective view of an example cutting assembly <NUM> consistent with various embodiments, <FIG> depicts a cross-sectional view y-y consistent with the example cutting assembly <NUM> of <FIG>, <FIG> is an exploded cross-sectional view of <FIG>, and <FIG> is another cross-sectional view z-z of <FIG> where the cutting assembly <NUM> is coupled to an example chassis <NUM>. The example cutting assembly <NUM> can be incorporated in various mowers, such as the example mower <NUM> described above. The cutting assembly <NUM> is generally configured to cut grass. The cutting assembly <NUM> has a motor housing <NUM> defining a motor cavity <NUM>, a tool motor <NUM> disposed in the motor cavity <NUM> and a tool <NUM> operatively coupled to the tool motor <NUM>. In various embodiments the tool <NUM> is a cutting blade assembly <NUM>.

The tool motor <NUM> is adapted to power at least one ground working tool as further described herein. While illustrated herein as an electric tool motor <NUM>, alternative prime movers, such as internal combustion engines, are also contemplated. The tool motor <NUM> has an output shaft <NUM> defining a motor axis xm that extends in a first direction through the motor cavity <NUM>. In various embodiments, the tool motor <NUM> is configured to rotate the output shaft <NUM> clockwise and counterclockwise relative to the motor axis xm.

A ground working tool (e.g., rotatable cutting blade assembly <NUM>) is coupled to the output shaft <NUM>. The cutting blade assembly <NUM> can have a plurality of (e.g., four) cutting blades <NUM> coupled to a cutting disk <NUM>, where the cutting disk <NUM> is coupled to the output shaft <NUM>. Each cutting blade <NUM> extends outward from the cutting disk <NUM> during operation. The cutting blade assembly <NUM> has a tool axis xt about which the cutting disk <NUM> is rotatable. In operation, the cutting blades <NUM> are configured to revolve about the tool axis xt. In various embodiments, the cutting blades <NUM> are configured to revolve about the tool axis xt in each of a clockwise direction and a counterclockwise direction. In some embodiments, the tool axis xt can be collinear with the motor axis xm. Each of the cutting blades <NUM> are coupled to the cutting disk <NUM> with a blade fastener <NUM> such as a bolt, screw, pin, or the like. In some embodiments, each of the cutting blades <NUM> can be pivotably coupled to the cutting disk <NUM> by the blade fastener <NUM>.

In the current example, a protective plate <NUM> is coupled to the output shaft <NUM> that is configured to be positioned between a ground surface (such as ground surface <NUM> in <FIG>) and the blade fastener <NUM>, but in some embodiments the protective plate <NUM> can be omitted. The cutting disk <NUM> can be attached, directly or indirectly, to the output shaft <NUM> by a disk fastener <NUM>. In particular, the various components of the cutting blade assembly <NUM> can define an output shaft opening <NUM> (<FIG>) that is configured to receive the output shaft <NUM>. The various components of the cutting blade assembly <NUM> can be fixed to the output shaft <NUM> by securing the disk fastener <NUM> to the output shaft <NUM> via, for example, mating threads mutually defined by the disk fastener <NUM> and the output shaft <NUM>.

During operation, the output shaft <NUM> rotates the cutting blade assembly <NUM> at a speed sufficient to permit the cutting blades <NUM> to sever grass <NUM> (see <FIG>) and other vegetation over which the deck <NUM> passes. By pivotably coupling each cutting blade <NUM> to the rotatable cutting disk <NUM>, the cutting blades are capable of incurring blade strikes against various objects (e.g., rocks, tree roots, etc.) without causing excessive damage to the cutting blades <NUM>, cutting blade assembly <NUM>, output shaft <NUM>, tool motor <NUM>, and/or other portions of the mower <NUM>. While described herein in the context of one or more cutting "blades," other cutting elements including, for example, conventional mower blades, flexible string or line elements, etc., are certainly possible without departing from the scope of this disclosure.

As stated above, the wheels <NUM> can be powered (e.g., by separate drive wheel motors <NUM>; see <FIG>) so that the mower <NUM> is self-propelled. While shown having four wheels, other embodiments can utilize any number of wheels (e.g., two or more). Still further, as used herein, "wheels" can refer to other ground-engaging members such as tracks, rollers, or skids.

Referring back generally to <FIG>, the mower <NUM> can have one or more sensors <NUM> (<FIG>) to assist with localization. For instance, some embodiments can have a global positioning system (GPS) receiver adapted to estimate a position of the mower <NUM> within the work region and provide such information to the controller <NUM> (see <FIG>). In other embodiments, one or more of the wheels <NUM>, <NUM> can have encoders (not shown) that provide wheel rotation/speed information that can be used to estimate mower position (e.g., based upon an initial start position) within a given work region. Other sensors (e.g., inertial measurement unit, vision (camera) sensor, infrared sensor, radio detection and ranging (radar) sensor, light detection and ranging (lidar) sensor, etc.) now known or later developed can also be incorporated into the mower <NUM>. The mower <NUM> can further have sensors adapted to detect a boundary wire when the latter is used to define a boundary of the work region.

Referring specifically to <FIG> and <FIG>, the controller <NUM> can be adapted to electronically monitor and control various mower functions. An exemplary controller can have a processor <NUM> (<FIG>) that receives various inputs and executes one or more computer programs or applications stored in memory <NUM>. The memory <NUM> can have computer-readable instructions or applications that, when executed, e.g., by the processor <NUM>, cause the controller <NUM> to perform various calculations and/or issue commands. That is to say, the processor <NUM> and memory <NUM> can together define a computing apparatus operable to process input data and generate the desired output to one or more components/devices. For example, the processor <NUM> can receive various input data including positional data from the GPS receiver and/or wheel encoders and generate speed and steering angle commands to drive wheel motors <NUM> and cause the rear wheels <NUM> to rotate (at the same or different speeds and in the same or different directions). The controller <NUM> can further control the cutting assembly <NUM> (e.g., both the tool motor <NUM> described above and an HOC control system, which will be described below). In other words, the controller <NUM> can control the steering angle and speed of the mower <NUM>, as well as the operation and height of the cutting blade assembly <NUM>.

In view of the above, it will be readily apparent that the functionality of the controller <NUM> can be implemented in any manner known to one skilled in the art. For instance, the memory <NUM> can have any volatile, non-volatile, magnetic, optical, and/or electrical media, such as a random-access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically-erasable programmable ROM (EEPROM), flash memory, and/or any other digital media. While shown as both being incorporated into the controller <NUM>, the memory <NUM> and the processor <NUM> could be contained in separate modules.

The processor <NUM> can have any one or more of a microprocessor, a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), and/or equivalent discrete or integrated logic circuitry. In some embodiments, the processor <NUM> can have multiple components, such as any combination of one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, and/or one or more FPGAs, as well as other discrete or integrated logic circuitry. The functions attributed to the controller/processor herein can be embodied as software, firmware, hardware, or any combination thereof. In at least one embodiment, various subsystems of the mower <NUM>, as described above, could be connected in most any manner, e.g., directly to one another, wirelessly, via a bus architecture (e.g., controller area network (CAN) bus), or any other connection configuration that permits data and/or power to pass between the various components (e.g., controller, tool motor, HOC control system (e.g., height adjustment or height adjustment motor as further described below), drive wheel motors <NUM>, GPS, wheel encoders, bump sensors, etc.) of the mower.

With specific reference to <FIG>, an exemplary tool drive system <NUM> is now described. The tool drive system <NUM> in combination with a HOC control system can together define the cutting assembly <NUM>. The tool drive system <NUM> has a prime mover in the form of a tool motor (e.g., electric tool motor <NUM>) secured to and directly supported by a motor mounting surface <NUM> on a frame, e g. , motor frame <NUM>. The motor frame <NUM> is configured to be coupled to the chassis <NUM> of a mower and supports a tool (e.g., cutting blade assembly <NUM>) relative to the chassis <NUM>. As further described below, the motor frame <NUM> is axially translatable relative to the chassis <NUM> (e.g., along axis xm) to allow adjustment of a height of the tool (e.g., cutting blade assembly <NUM>) relative to the ground surface <NUM>.

The tool motor <NUM> can be fixed to the motor frame <NUM> where it can rest upon a flange <NUM> defining at least a portion of the motor mounting surface <NUM>. In particular, the tool motor <NUM> can have a mating surface <NUM> that is configured to be mounted to the motor mounting surface <NUM>. The motor mounting surface <NUM> can define fastener openings <NUM> (one of which is visible in <FIG>) that are configured to align with aligning fastener openings of the tool motor <NUM> (not currently visible) to mutually receive a fastener (not shown) to secure the tool motor <NUM> to the motor mounting surface <NUM>. In some embodiments, the motor mounting surface <NUM> is orthogonal to the motor axis xm. In some embodiments, the motor mounting surface <NUM> is orthogonal to the tool axis xt.

The tool motor <NUM> can have a wiring harness <NUM> (visible in <FIG>) to permit communication of the tool motor <NUM> with the controller <NUM> (see <FIG>). A power cord <NUM> is coupled to the tool motor <NUM> that is configured to provide power to the tool motor <NUM> from the battery <NUM> (see <FIG>) to selectively rotate the cutting blade assembly <NUM>. In some embodiments, the motor housing <NUM> can be provided to cover portions of the tool drive system <NUM> and HOC control system located above the chassis <NUM>.

A motor key <NUM> can be secured to the output shaft <NUM> of the tool motor <NUM> such that the motor key <NUM> rotates with the output shaft <NUM>. The motor key <NUM> can be received within a keyway <NUM> (visible in <FIG>) formed in the cutting disk <NUM> of the cutting blade assembly <NUM> to permit transmission of rotational force from the tool motor <NUM> to the cutting disk <NUM>.

The motor cavity <NUM>/motor housing <NUM> has a central axis, which is referred to herein as the housing axis xh, extending in the axial direction. In a variety of embodiments, the housing axis xh of the motor housing <NUM> is oblique to each of the motor mounting surface <NUM>, the motor axis xm and the tool axis xt. As such, the housing axis xh is nonparallel to the tool axis xt and the motor axis xm. In such embodiments, the cutting blade assembly <NUM> can be configured to operate in a plane Pc that is oblique to a generally planar ground surface <NUM> (<FIG>). The angle between the plane Pc defined by the cutting blade assembly <NUM> and a generally planar ground surface <NUM> can be referred to as the "rake angle" of the vehicle <NUM> (which is a mower <NUM> in the current example). The rake angle is generally measured from the front to the back of the vehicle <NUM>. In some embodiments, however there can be an angle from the right side to the left side of the vehicle (or vice versa). The angle can range from <NUM>° to <NUM>°, <NUM>° to <NUM>° or <NUM>° to <NUM>°, in embodiments. In one particular example, the angle is <NUM>°. The angle between the motor axis xm and/or tool axis xt and the housing axis xh can be equivalent to the angle, in various embodiments.

As stated above, the cutting assembly <NUM> can also have the HOC control system as shown in <FIG>. The HOC control system can be used to adjust the relative height of the cutting blades <NUM> (e.g., of the cutting disk <NUM>) relative to the chassis <NUM> or the ground surface <NUM> (see <FIG>) to allow corresponding variation in the height of cut grass <NUM>. In various embodiments, the HOC control system does not modify the angle (such as the rake angle) of the cutting blade assembly <NUM>.

With reference first to <FIG>, the exemplary HOC control system is defined, in part, by components of the motor housing <NUM>. The motor housing <NUM> is generally coupled to the chassis <NUM> and defines the motor cavity <NUM> extending in the axial direction. The motor housing <NUM> has a first inner housing portion <NUM> and a second inner housing portion <NUM>. Each of the first inner housing portion <NUM> and the second inner housing portion <NUM> are translatable relative to the chassis and are operatively coupled to modify the height of the cutting blades <NUM>. The first inner housing portion <NUM> has the motor frame <NUM>, which defines the motor mounting surface <NUM>.

The chassis <NUM> defines a cutting assembly opening <NUM> (see <FIG>). The cutting assembly <NUM> extends from the upper portion of the chassis <NUM> to the cutting chamber <NUM> through the cutting assembly opening <NUM>. In particular, the first inner housing portion <NUM> extends through the cutting assembly opening <NUM> such that the cutting blade assembly <NUM> is positioned between the chassis <NUM> and the ground surface <NUM>. The cutting blade assembly <NUM> is generally positioned below the chassis. The tool motor <NUM> is generally housed above the chassis <NUM>.

The first inner housing portion <NUM> and the second inner housing portion <NUM> are in threaded engagement. The first inner housing portion <NUM> defines a first helical thread <NUM> about the motor cavity <NUM> and the second housing portion defines a second helical thread <NUM> about the motor cavity <NUM>. The second helical thread <NUM> engages the first helical thread <NUM>. The first inner housing portion <NUM> is axially translatable and generally rotatably fixed relative to the chassis, and the second inner housing portion <NUM> is axially fixed relative to the chassis and rotatable relative to the chassis. As such, when the second inner housing portion <NUM> rotates relative to the chassis (and the first inner housing portion <NUM>), the interaction between the first helical thread <NUM> and the second helical thread <NUM> results in axial translation of the first inner housing portion <NUM> and, therefore, the motor mounting surface <NUM> and the cutting blade assembly <NUM>, relative to the chassis (and the second inner housing portion <NUM>) along axis xm.

In the current example, the first inner housing portion <NUM> defines an external (i.e., male) helical thread <NUM> and the second inner housing portion <NUM> defines an internal (i.e., female) helical thread <NUM>, but the opposite configuration is certainly possible in other examples.

In examples consistent with the currently-described figures, the vehicle has a height adjustment drive <NUM> that is configured to adjust the height of the cutting blade assembly <NUM> relative to the ground and/or the chassis <NUM>. The height adjustment drive <NUM> has a height adjustment motor <NUM> that is in operative communication with the second inner housing portion <NUM>. In particular, the second inner housing portion <NUM> defines gear teeth <NUM> about the motor cavity <NUM>, and a pinion gear <NUM> engages the gear teeth <NUM> of the second inner housing portion <NUM>. The height adjustment motor <NUM> is configured to selectively rotate the pinion gear <NUM> in response to a command input to change the height of the cutting blade assembly <NUM>. More particularly, the height adjustment motor <NUM> has an output shaft <NUM> that is fixed to the pinion gear about a shaft opening <NUM> defined thereby. Rotating of the pinion gear <NUM> results in rotation of the second inner housing portion <NUM>, which results in axial translation of the first inner housing portion <NUM>. In some embodiments, the height adjustment motor <NUM> can be omitted, and a manually rotatable handle can be in rotatable communication with the pinion gear <NUM>. The direction of rotation of the pinion gear <NUM> can be controlled to correspondingly change the direction of axial translation of the first inner housing portion <NUM>.

In some embodiments, the HOC control system has a sensor system having one or more sensors in the vehicle <NUM> that provide feedback to the controller <NUM> that represents the estimated height of the cutting blade assembly <NUM>. The controller <NUM> can use the data representing the estimated height of the cutting blade assembly <NUM> to selectively operate the height adjustment motor <NUM> to achieve the desired cutting blade assembly <NUM> height.

A variety of types of sensors can be used in the sensor system to sense data representing the height of the cutting blade assembly <NUM>. A proximity sensor, such as an electromagnetic sensor, an ultrasonic sensor, photoelectric sensor, or types of proximity sensors, can be configured to sense an axial distance between particular components that correlates with the height of the cutting blade assembly <NUM>. For example, a proximity sensor can be positioned on a bottom surface of the chassis <NUM> or a top surface of the cutting disk to sense the distance between a bottom surface of the chassis <NUM> (visible in <FIG>) and the top surface of the cutting disk <NUM>. As another example, a proximity sensor can be positioned on the annular segment <NUM> to sense the distance between the annular segment <NUM> and an outer body <NUM> (the outer body <NUM> is described in more detail, below).

In the current example, as visible in <FIG>, a proximity sensor <NUM> is positioned on an underside of a casing cover <NUM> in sensing alignment with a portion of the first inner housing portion <NUM>. For example, the proximity sensor <NUM> is positioned in axial alignment with an end surface <NUM> of an inner body <NUM> of the first inner housing portion <NUM> to sense the distance between the casing cover <NUM> and the end surface <NUM> of the inner body <NUM>. In an example, a target <NUM> can be positioned on the end surface <NUM> of the inner body <NUM> that is in sensing alignment with the proximity sensor. The proximity sensor <NUM> can be configured to sense the distance of the target <NUM>. Both the casing cover <NUM> and the inner body <NUM> are described in detail, below.

In some embodiments the sensor system can be configured to sense the rotational position of the second inner housing portion <NUM> or the pinion gear <NUM> (as examples), which the system can be configured to correlate with the height of the cutting blade assembly <NUM>. For example, an encoder can have one or more targets (such as a magnet). The encoder is positioned on one of either a rotationally fixed component or a rotatable component, and each of the one or more targets are positioned on the other of the rotationally fixed component or the rotatable component. The encoder is configured to detect passage of each of the targets as the rotatable component is rotated. The sensed passage of each of the targets can correlate with a particular height of the cutting blade assembly <NUM> based on the pitch of the helical threads <NUM>, <NUM>. As a more specific example, the encoder can be positioned on an underside of the casing cover <NUM> and a plurality of targets can be positioned on or adjacent the gear teeth <NUM>. In such an example, the encoder can be circumferentially aligned with each of the targets about the central axis of the housing xh such that, as the gear teeth <NUM> are rotated about the housing axis xh, each of the targets are detectable by the encoder.

The cutting blade assembly <NUM> height can be adjusted from a minimum height Hmin to a maximum height Hmax (Hmax is depicted in <FIG>; Hmin is not currently depicted). The minimum height Hmin corresponds to the position of the cutting blade assembly <NUM> at its furthest axial distance from the chassis <NUM> and its closest axial distance to a substantially planar ground surface <NUM> (resulting in a minimum height-of-cut of grass, for example). The maximum height Hmax corresponds to the position of the cutting blade assembly <NUM> at its closest axial distance to the chassis <NUM> and its furthest axial distance to the substantially planar ground surface <NUM> (resulting in a maximum height-of-cut of grass, for example).

During autonomous operation of the mower <NUM>, the controller <NUM> (see <FIG>) can control rotation of the second inner housing portion <NUM> and thus adjust the height of the cutting blades <NUM>/cutting blade assembly <NUM> relative to the ground surface <NUM> in response to a signal received by the controller <NUM>. For example, the signal could be generated by the sensor <NUM> (diagrammatically illustrated in <FIG>) in communication with the controller <NUM>. The sensor <NUM> can, in some embodiments, be selected from a grass height sensor, a moisture sensor, and a cutting motor load (e.g., current) sensor. The controller <NUM> can, upon receipt of the signal, automatically increase or decrease the height-of-cut (e.g., control rotation of the second inner housing portion <NUM>) to ensure effective cutting quality.

In some embodiments, the signal to change the cutting height of the cutting blade assembly <NUM> can be a command issued by an operator, e.g., received via the radio <NUM> from a remote computer <NUM> (such as a mobile phone or tablet; <FIG>) or remote control, or provided directly via a control panel <NUM> located on the mower itself. That is to say, the operator can manually input the desired height-of-cut, after which the controller <NUM> will command the rest of the HOC control system to provide the desired height. In some embodiments, the controller <NUM> can receive a signal representative of a calendar date and then automatically adjust the height-of-cut to better complement the particular mowing season, e.g., a lower height of cut can be automatically selected during autumn.

In some embodiments, the sensor system may be periodically calibrated to maintain accuracy of the estimated height of the cutting blade assembly <NUM> determined by the HOC control system. For example, on a periodic basis (e.g., daily, weekly, monthly, or after the expiration of a certain number of operating hours), the controller <NUM> can command the height adjustment motor <NUM> to raise the cutting blade assembly <NUM>/motor frame <NUM> to its maximum height Hmax. As this occurs, the second inner housing portion <NUM> can rotate until the first inner housing portion <NUM> eventually reaches a stop, at which point the height adjustment motor <NUM> will stall. Such a stall may be detected by, among other methods, the controller <NUM> detecting an increase in motor <NUM> current. Once stall is detected, the controller <NUM> can terminate current to the height adjustment motor <NUM> and set the position of the first inner housing portion as equal to the maximum height Hmax. Upon receiving a command to change the cutting height (e.g., directly from the controller <NUM> or indirectly via a remote computer <NUM> (see <FIG>)), the controller <NUM> can command the height adjustment motor <NUM> to rotate the second inner housing portion <NUM> to adjust the cutting height. The controller <NUM> can estimate a vertical position of the cutting blade assembly <NUM> by monitoring the sensor system.

To minimize debris/moisture ingress from the cutting chamber <NUM> (see <FIG> and <FIG>) into the area above the chassis <NUM>, a seal <NUM> can be disposed between the chassis and the tool drive system <NUM>. While various configurations are certainly possible, the seal <NUM> can be a flexible annular lip seal that is attached (e.g., fastened, adhered, etc.) to the chassis <NUM> to engage with interference to form a seal with the motor housing <NUM> as the latter translates relative to the chassis <NUM>. The seal <NUM> generally extends radially inward from the chassis <NUM> to frictionally engage an outer surface of the first inner housing portion <NUM> around the first inner housing portion <NUM>. The seal <NUM> can be constructed of a variety of materials and combinations of materials, such as an elastomeric material such as rubber. In the current example, the seal <NUM> is disposed between the first inner housing portion <NUM> and the chassis <NUM> about the cutting assembly opening <NUM> and is in sealing contact with both the chassis <NUM> and the first inner housing portion <NUM>. In various embodiments the seal <NUM> is a wiper seal. The wiper seal can have a wiper lip <NUM> that contacts the surface of the first inner housing portion <NUM>. In such examples the wiper lip <NUM> is configured to scrape the surface of the first inner housing portion <NUM> as the first inner housing portion <NUM> translates axially through the cutting assembly opening <NUM> of the chassis. Such scraping functionality can prevent debris on the surface of the first inner housing portion <NUM>.

As one of skill can appreciate, the fit between the first helical thread <NUM> of the first inner housing portion <NUM> and the second helical thread <NUM> of the second inner housing portion <NUM> can contribute to the quality of operation when adjusting the height of the cutting blade assembly <NUM>. It is generally desirable to translate the motor frame <NUM> upwardly and downwardly without applying excessive force and without binding or chatter during mowing. In some embodiments, smooth operation can be accomplished by tightly controlling and reducing tolerances of the size, location, and parallelism of both the first inner housing portion <NUM> and the second inner housing portion <NUM>. However, providing such reduced tolerances between components can increase the cost and complexity of manufacture.

In some embodiments it can be desirable to relax the tolerances between the first inner housing portion <NUM> and the second inner housing portion <NUM>. In such embodiments the seal <NUM> between the chassis <NUM> and the first inner housing portion <NUM> can exert a stabilizing force on the first inner housing portion <NUM> relative to the chassis <NUM>. The seal <NUM> can frictionally engage an outer surface of the first inner housing portion <NUM> about the first inner housing portion <NUM>. As a result, axial translation of the motor frame <NUM> in each direction can occur relatively smoothly and with limited (or no) binding. Furthermore, shifting of the first inner housing portion <NUM> (and, therefore, the motor frame <NUM>) in the lateral and longitudinal (fore-and-aft) directions can be reduced or eliminated. By reducing this free play, the cutting blade assembly can operate effectively (e.g., without chattering) even when cutting relatively high grass.

The first inner housing portion <NUM> has a variety of different structures to be consistent with the technology disclosed herein. As mentioned above, the first inner housing portion <NUM> has the motor mounting surface <NUM> that is fixed to the tool motor <NUM>. The first inner housing portion <NUM> has an inner body <NUM> that extends from the motor mounting surface <NUM> towards the second inner housing portion <NUM>. Indeed, as is visible in <FIG>, the first inner housing portion <NUM> extends into the second inner housing portion <NUM>. The inner body <NUM> of the first inner housing portion <NUM> defines the first helical thread <NUM>, as discussed above.

The first inner housing portion <NUM> also has an outer body <NUM> extending axially from the motor mounting surface <NUM> towards the second inner housing portion <NUM>. The outer body <NUM> and the inner body <NUM> define an annular gap <NUM> that receives a portion of the second inner housing portion <NUM>. The outer body <NUM> of the first inner housing portion <NUM> defines an outer cylindrical surface <NUM> that is in contact with the seal <NUM> and translates in the axial direction against the seal <NUM> as the height of the cutting blade assembly <NUM> is adjusted.

In the current example, the first inner housing portion <NUM> has an inner body <NUM>, an outer body <NUM>, and a motor frame <NUM> that are separate components fixed together, but in some other embodiments the inner body <NUM>, outer body <NUM> and/or the motor frame <NUM> can be a single, unitary structure.

In various embodiments the motor housing <NUM> has a casing <NUM> that is generally configured to house portions of the HOC control system positioned above the chassis. The casing <NUM> generally houses the first inner housing portion <NUM> and the second inner housing portion <NUM>. The casing <NUM> surrounds the first inner housing portion <NUM> and the second inner housing portion <NUM> above the chassis <NUM>. In the current example, the casing <NUM> has a main section <NUM> that extends axially from the chassis <NUM> towards the gear teeth <NUM> of the second inner housing portion <NUM>. The casing <NUM> has a secondary section <NUM> that is fixed to the main section <NUM>. In various embodiments the secondary section <NUM> and the main section <NUM> form a seal. The secondary section <NUM> extends axially from the main section <NUM> to surround the gear teeth <NUM> of the second inner housing portion <NUM> and the pinion gear <NUM> (<FIG>). The casing <NUM> also has a casing cover <NUM> fixed to the secondary section <NUM>. The casing cover <NUM> extends across the distal end of the secondary section <NUM>, where the "distal end" is the end furthest from the chassis <NUM> in the axial direction. In various embodiments, the casing cover <NUM> and the secondary section <NUM> form a seal.

While the casing <NUM> has three main components in the example design, in some other embodiments the casing can be formed with fewer components or more components. In some examples, the main section <NUM> and the secondary section <NUM> can form a unitary structure. In some examples, the secondary section <NUM> and the casing cover <NUM> can form a unitary structure. The casing <NUM>, in particular the main section <NUM> of the casing <NUM>, is fixed to the chassis <NUM> with one or more fasteners (not currently visible). As such, the casing <NUM> is axially fixed and rotatably fixed relative to the chassis <NUM>. A casing seal <NUM> can be disposed between the casing <NUM> and the chassis <NUM>. While in the current example, the casing <NUM> does not extend around the height adjustment motor <NUM>, in some other embodiments, the casing <NUM> does extend around the height adjustment motor <NUM> to contain the height adjustment motor <NUM>.

In examples consistent with the current design, the casing <NUM> forms a mounting structure <NUM> on which the second inner housing portion <NUM> is rotatably mounted. In particular, the main section <NUM> of the casing <NUM> has an inner wall <NUM> extending in the axial direction about the housing axis xh. The inner wall <NUM> has a cylindrical shape. The inner wall <NUM> defines a chamber <NUM> (<FIG>) that is configured to receive the second inner housing portion <NUM> and accommodate rotation of the second inner housing portion <NUM>. As such, the chamber <NUM> has a central axis that is the housing axis xh.

The inner wall <NUM> of the casing <NUM> is radially spaced from the main section <NUM> and fixed to the main section <NUM> via an annular segment <NUM> towards the distal end of the main section <NUM>. The mounting structure <NUM> has an inwardly extending radial flange <NUM> towards a proximal end of the inner wall <NUM> that forms a first annular mounting surface <NUM> which receives and accommodates rotation of a proximal end <NUM> of the second inner housing portion <NUM>. The mounting structure <NUM> also has a second annular mounting surface <NUM> on its distal end that is configured to receive and accommodate rotation of a portion of the second inner housing portion <NUM>. The mounting structure <NUM> can have other configurations, as well. In the current example, the main section <NUM>, annular segment <NUM> and inner wall <NUM> are a unitary structure, but in other embodiments one or more of those elements can be separate components that are fixed together.

The outer body <NUM> of the first inner housing portion <NUM> extends axially into the annular space between the inner wall <NUM> and the main section <NUM> of the casing <NUM>. Also, the inner wall <NUM> extends axially into the annular gap <NUM> between the inner body <NUM> and outer body <NUM>. Such a configuration creates a tortuous fluid pathway radially inward from the outside of the main section <NUM> towards the tool motor <NUM>.

In various embodiments the first inner housing portion <NUM> is rotatably fixed relative to the chassis <NUM> via a radial alignment feature <NUM> (best visible in <FIG>) that is configured to radially align the first inner housing portion <NUM> and the casing <NUM>. In the current example the radial alignment feature <NUM> is a protrusion <NUM> extending radially from the outer body <NUM> of the first inner housing portion <NUM> that is received by a corresponding radial slot <NUM> defined by the casing <NUM>. The radial slot <NUM> extends axially along the casing <NUM> to accommodate the protrusion <NUM> across the axial translation range of the first inner housing portion <NUM>. In this particular example, the protrusion <NUM> extends radially outward from the outer body <NUM> and the radial slot <NUM> is defined by the main section <NUM> of the casing <NUM>. Other configurations can be used, however. For example, the casing <NUM> can define a radial protrusion and the first inner housing portion <NUM> can define a corresponding radial slot. In some embodiments the radial protrusion can extend radially inward.

<FIG> depicts another example cross-sectional view p-p of the cutting assembly <NUM> of <FIG> such that the routing of the power cord <NUM> through the cutting assembly <NUM> to the tool motor <NUM> is more clearly visible. In this example, the main section <NUM> and the outer body <NUM> of the first inner housing portion <NUM> defines a first cord opening <NUM> through which the power cord <NUM> passes. The main section <NUM> has a cord housing <NUM> extending radially outward from the rest of the main section <NUM>. The cord housing also extends axially downward towards the chassis <NUM> (not currently depicted, but the cord housing <NUM> and the chassis <NUM> are partially visible in <FIG>). Like the rest of the main section <NUM>, the cord housing <NUM> forms a seal with the chassis <NUM>. The cord housing <NUM> defines a second cord opening <NUM> through which the power cord <NUM> passes from outside the cutting assembly <NUM> to inside the cutting assembly <NUM>. A cord seal <NUM> can be disposed between the cord housing <NUM> and the power cord <NUM> in the second cord opening <NUM>.

The power cord <NUM> is generally routed through the components of the cutting assembly <NUM> that are rotatably fixed relative to the chassis <NUM>. In particular, in this example, the power cord <NUM> is routed from outside the cutting assembly <NUM> through the second cord opening <NUM> and from the cord housing <NUM> through the first cord opening <NUM>. From the first cord opening <NUM> the power cord <NUM> extends axially towards the chassis <NUM> within a gap between the outer body <NUM> of the first inner housing portion <NUM> and the inner wall <NUM> of the main section <NUM>. The power cord <NUM> passes through a third cord opening <NUM> defined by the inner body <NUM> of the first inner housing portion <NUM> and extends axially along the motor cavity <NUM> to the tool motor <NUM>. Notably, the power cord <NUM> bypasses the second inner housing portion <NUM>, which is rotatable relative to the chassis <NUM>. The power cord <NUM> does not pass through the second inner housing portion <NUM>. Such a configuration can prevent wrapping of the power cord <NUM> about system components as the second inner housing portion <NUM> is rotated.

The cord housing <NUM> and motor cavity <NUM> can generally be configured to house a linear length of the power cord <NUM> to accommodate axial translation of the cutting blade assembly <NUM> (and, therefore, the tool motor <NUM>) from the minimum height Hmin to the maximum height Hmax positions.

While described above as utilizing a powered or automatic HOC control system (using the height adjustment motor <NUM>), such a configuration is not limiting. For example, embodiments in which the mower operator can manually adjust the height-of-cut are also contemplated. <FIG> illustrates a cross-sectional view of such a manual height adjustment system of a cutting assembly <NUM> consistent with <FIG>, and <FIG> is an exploded view consistent with <FIG>.

In general, the cutting assembly <NUM> can be similar to the cutting assembly <NUM> already described herein with respect to <FIG> and, as a result, like reference numerals are used where appropriate. The descriptions of similar components described earlier herein generally apply to corresponding components in the current figure unless contradictory to the current description. The cutting assembly <NUM> can have a motor housing <NUM> that is configured to be coupled to a chassis <NUM> (<FIG>). The motor housing <NUM> defines a motor cavity <NUM> extending in an axial direction. The motor housing <NUM> has a first inner housing portion <NUM> and a second inner housing portion <NUM>. Each of the first inner housing portion <NUM> and the second inner housing portion <NUM> are translatable relative to the chassis <NUM> and are operatively coupled to modify the height of cutting blades <NUM> in a cutting blade assembly <NUM>. The first inner housing portion <NUM> has the motor frame <NUM>, which defines the motor mounting surface <NUM>. A tool motor <NUM> is fixed to the motor mounting surface <NUM>. The tool motor <NUM> has an output shaft <NUM> extending in a first direction (e.g., in the direction of central axis xh).

The first inner housing portion <NUM> and the second inner housing portion <NUM> are in threaded engagement. The first inner housing portion <NUM> defines a first helical thread <NUM> about the motor cavity <NUM> and the second housing portion defines a second helical thread <NUM> about the motor cavity <NUM>. The second helical thread <NUM> engages the first helical thread <NUM>. The first inner housing portion <NUM> is axially translatable and rotatably fixed relative to the chassis <NUM>, and the second inner housing portion <NUM> is axially fixed relative to the chassis <NUM> and rotatable relative to the chassis <NUM>. As such, when the second inner housing portion <NUM> rotates relative to the chassis <NUM> (and the first inner housing portion <NUM>), the interaction between the first helical thread <NUM> and the second helical thread <NUM> results in axial translation of the first inner housing portion <NUM> and, therefore, the motor mounting surface <NUM> and the cutting blade assembly <NUM>, relative to the chassis <NUM> (and the second inner housing portion <NUM>).

The currently described cutting assembly <NUM> differs from previously described examples, however, in that it eliminates the height adjustment motor <NUM> of the height adjustment drive <NUM> of <FIG>. In its place, the height adjustment drive <NUM> can have a manual turn screw <NUM> fixed to the second inner housing portion <NUM>. The turn screw <NUM> can extend axially through the motor housing <NUM> (in particular, the casing cover <NUM> of the motor housing <NUM>) and can have an axis of rotation that is colinear with the housing axis xh. A knob <NUM> can be attached or otherwise affixed to an upper end of the turn screw <NUM> such that rotation of the knob <NUM> causes rotation of the turn screw <NUM> and, correspondingly, rotation of the second inner housing portion <NUM>. In particular, a cover <NUM> is fixed to a distal end <NUM> of the second inner housing portion <NUM> and extends across a distal end of the motor cavity <NUM>. The turn screw <NUM> is fixed to the cover <NUM> such that manual rotation of the turn screw <NUM> results in rotation of the second inner housing portion <NUM>. For the same reasons already set forth herein, such drive screw rotation can proportionally adjust the height-of-cut by axially translating the motor frame <NUM> (via the first inner housing portion <NUM>) upwardly or downwardly. In some embodiments, a <NUM>° rotation of the drive screw results in linear translation of the cutting blade assembly <NUM> across its full range.

The knob <NUM> can protrude outside and above the motor housing <NUM> so that it is accessible to the operator as needed. For example, as visible in <FIG>, the roof portion <NUM> of the bump shroud <NUM> can have a knob access opening <NUM> through which a user can access the knob <NUM>. In some embodiments, a knob access cover can be disposed over the knob access opening <NUM>. In such embodiments the knob access cover can be a hinged or sliding cover over the knob access opening <NUM> through which the knob <NUM> is accessible. In some embodiments, the knob <NUM> can have a crank offset from the rotational axis of the turn screw <NUM> to provide an alternate gripping surface for rotation of the knob <NUM>. In some embodiments, such a crank can fold or telescope outwardly from the knob when needed and otherwise collapse. Yet other embodiments can forgo the crank altogether in lieu of some other type of easily gripped knob surface, e.g., knurls, spokes, depressions, etc., consistent with <FIG> and <FIG>.

While shown as extending upwardly through a top of the motor housing <NUM>, the knob <NUM> of the turn screw <NUM> can alternatively extend through one of the sides of the motor housing <NUM>. In such a case, the height adjustment drive <NUM> might require additional elements (e.g., bevel gears, shafts, etc.) to convert rotation of the knob to rotation of the turn screw <NUM>.

In some embodiments, a cutting assembly <NUM>/<NUM> can be designed to have a modular configuration such that a height adjustment drive can be optionally manual or automatic. For example, the second inner housing portion <NUM>, the height adjustment drive <NUM>, the casing cover <NUM> and the secondary section <NUM> consistent with <FIG> is configured to be detached from the cutting assembly <NUM> and replaced with the second inner housing portion <NUM>, the height adjustment drive <NUM>, the casing cover <NUM> and the secondary section <NUM> of <FIG>. In some embodiments the height adjustment motor <NUM> depicted in <FIG> is configured to be detachable from the pinion gear <NUM> and a manually rotatable handle is configured to be attached in operable communication with the pinion gear <NUM>. In some embodiments, the knob <NUM> and, potentially, the turn screw <NUM> are replaceable with a height adjustment motor having an output shaft that is configured to be coupled to the cover <NUM>. Other embodiments are certainly contemplated.

<FIG> depicts yet another example of a cutting assembly <NUM>, consistent with various embodiments. In general, the cutting assembly <NUM> can be similar to the cutting assembly <NUM> already described herein with respect to <FIG> and, as a result, like reference numerals are used where appropriate. The descriptions of similar components described earlier herein generally apply to corresponding components in the current figure unless contradictory to the current description.

The cutting assembly <NUM> has a motor housing <NUM> that is configured to be coupled to a chassis <NUM> (<FIG>). The motor housing <NUM> defines a motor cavity <NUM> extending in an axial direction xh. The motor housing <NUM> has a first inner housing portion <NUM> and a second inner housing portion <NUM>. Each of the first inner housing portion <NUM> and the second inner housing portion <NUM> are translatable relative to the chassis <NUM> and are operatively coupled to modify the height of cutting blades <NUM> in a cutting blade assembly <NUM>. The first inner housing portion <NUM> has the motor frame <NUM>, which defines the motor mounting surface <NUM>. A tool motor <NUM> is fixed to the motor mounting surface <NUM>. The tool motor <NUM> has an output shaft <NUM> extending in a first direction (e.g., in the direction of central axis of the motor xm).

The first inner housing portion <NUM> and the second inner housing portion <NUM> are in threaded engagement. The first inner housing portion <NUM> defines a first helical thread <NUM> about the motor cavity <NUM> and the second inner housing portion <NUM> defines a second helical thread <NUM> about the motor cavity <NUM>, similar to previously-described examples. The first helical thread <NUM> and the second helical thread <NUM> are in threaded engagement about the central axis of the housing xh. The first inner housing portion <NUM> is axially translatable and rotatably fixed relative to the chassis <NUM>. The second inner housing portion <NUM> is axially fixed relative to the chassis <NUM> and rotatable relative to the chassis <NUM>. As such, when the second inner housing portion <NUM> rotates relative to the chassis <NUM> (and the first inner housing portion <NUM>), the second helical thread <NUM> rotates relative to the first helical thread <NUM>, which results in axial translation of the first inner housing portion <NUM> and, therefore, the motor mounting surface <NUM> and the cutting blade assembly <NUM>, relative to the chassis <NUM> (and the second inner housing portion <NUM>).

The current example has a modified seal configuration compared to previously depicted examples. A seal assembly <NUM> is configured to be disposed across the cutting assembly opening <NUM> between the chassis <NUM> (see <FIG> and <FIG>) and the motor housing <NUM> to limit the ingress of debris to the motor cavity <NUM>. In the current example, the seal assembly <NUM> has a bellows <NUM> that forms a seal between the chassis <NUM> and the cutting assembly <NUM> across the cutting assembly opening <NUM>. The bellows <NUM> has a first end <NUM> that is configured to be sealed to the chassis <NUM> about the cutting assembly opening <NUM>. The bellows <NUM> has a second end <NUM> that is sealed around a portion of the motor housing <NUM> (such as the first inner housing portion <NUM>) that is positioned within the cutting assembly opening <NUM> (see <FIG>). As such, the bellows <NUM> defines a barrier across the cutting assembly opening <NUM> between the chassis <NUM> and the motor housing <NUM>. In various embodiments, the second end <NUM> of the bellows <NUM> is coupled to the first inner housing portion <NUM>. In particular, the second end <NUM> of the bellows <NUM> is coupled to the first inner housing portion <NUM> towards the end <NUM> of the first inner housing portion <NUM> under the chassis <NUM>.

The bellows <NUM> lengthens and shortens in the axial direction between a collapsed configuration and an expanded configuration, which accommodates the range of axial translation of the first inner housing portion <NUM> relative to the chassis <NUM>. At the minimum cutting height Hmin the bellows <NUM> is in its expanded position and at the maximum cutting height Hmax, the bellows <NUM> is in its collapsed position.

In the current example, the seal assembly <NUM> has an annular seal <NUM> that sealably couples the bellows <NUM> to the chassis <NUM> about the cutting assembly opening <NUM>. The annular seal <NUM> is configured to be attached, such as with a fastener <NUM>, to the chassis <NUM>. The seal <NUM> is configured to be disposed between the first inner housing portion <NUM> and the chassis <NUM> about the cutting assembly opening <NUM> (similar to as depicted in <FIG>). In various embodiments, the annular seal <NUM> has a stabilizer portion <NUM> that is configured to exert a stabilizing force on the first inner housing portion <NUM> relative to the chassis <NUM>, as has been discussed above. The stabilizer portion <NUM> extends radially inward from the bellows <NUM> towards the first inner housing portion <NUM>. The stabilizer portion <NUM> frictionally engages the outer surface of first inner housing portion <NUM> around the first inner housing portion <NUM>. In some embodiments the stabilizer portion <NUM> is a single cohesive inner radial surface in surrounding engagement with the first inner housing portion <NUM>. In some embodiments the stabilizer portion <NUM> is a series of discrete surfaces each engaging the first inner housing portion <NUM> and collectively surrounding the first inner housing portion <NUM>.

In some embodiments, similar to examples described above, the annular seal <NUM> can also be configured to sealably engage the motor housing <NUM> as it axially translates relative to the chassis <NUM>. The seal <NUM> makes sealing contact with the first inner housing portion <NUM> in addition to the chassis <NUM>. Similar to the examples discussed above, the seal <NUM> can be a wiper seal where the stabilizing portion <NUM> further defines a wiper lip that is configured to scrape the surface of the first inner housing portion <NUM> as it translates axially through the cutting assembly opening <NUM> (see <FIG>).

Cutting assemblies <NUM>, <NUM> consistent with the technology disclosed herein can incorporate cutting blades having a variety of different configurations and combinations of configurations. <FIG> depict an example cutting blade <NUM>, such as a cutting blade <NUM> visible in <FIG>. As described above, the cutting assembly <NUM> can have a cutting disk <NUM> coupled to the output shaft <NUM> of the tool motor <NUM>, and a plurality of cutting blades <NUM> can be coupled to the cutting disk <NUM>. Each cutting blade <NUM> can extend outward from the cutting disk <NUM>.

Referring now specifically to <FIG>, where <FIG> is a facing view of a profile of an example cutting blade <NUM>, <FIG> is a perspective view of the example cutting blade <NUM>, and <FIG> is a facing view of a distal end <NUM> of the example cutting blade <NUM>. The cutting blade <NUM> generally has a blade body <NUM> having a proximal end <NUM>, a distal end <NUM>, and a length LB extending from the proximal end <NUM> to the distal end <NUM>. The term "distal end" in the context of the cutting blade <NUM> is the outermost end of the blade relative to the central axis xm of the motor <NUM>. The cutting blade <NUM> has a first face <NUM> and a second face <NUM>. The cutting blade <NUM> has a thickness T from the first face <NUM> to the second face <NUM> (<FIG>).

The proximal end <NUM> is generally configured to be coupled to a cutting disk <NUM>, which is visible in <FIG> and <FIG>. In this example, the blade body <NUM> defines a fastener opening <NUM> towards the proximal end <NUM>. The fastener opening <NUM> is configured to receive a blade fastener <NUM> that fastens the cutting blade <NUM> and the cutting disk <NUM>. The proximal end <NUM> has a length LP. The length of the proximal end LP is generally in a width direction, which is orthogonal to both the blade length LB of the blade body <NUM> and the blade thickness T of the blade body <NUM>. In various embodiments, the length of the proximal end LP is the narrowest portion of the blade body <NUM> in the width direction. In the current example, the proximal end <NUM> generally defines a plane surface, but in other embodiments the proximal end <NUM> can define a segmented or curved surface.

The distal end <NUM> of the blade body <NUM> is configured to be positioned outward from the cutting disk (also visible in <FIG>). In a variety of embodiments, the distal end <NUM> defines a plane surface orthogonal to the blade length LB. The distal end <NUM> defines a distal end length LD orthogonal to the blade length LB and the blade thickness T. In a variety of embodiments, the length of the distal end LD defines a widest portion of the blade body <NUM> in the width direction. The length of the distal end LD can vary, but in various embodiments the length of the distal end LD is at least <NUM>.

The blade body <NUM> is generally configured such that the width of the blade body tapers from the distal end towards the proximal end. Such a configuration distributes the center of mass of the cutting blade <NUM> closer to the distal end <NUM> than the proximal end <NUM>. As discussed above, when a mower is in operation, the cutting disk <NUM> (<FIG>) rotates about the output shaft <NUM>, which rotates each of the cutting blades <NUM> about the output shaft <NUM>. Positioning the center of mass closer to the distal end <NUM> than the proximal end <NUM> of the blade body <NUM> can help resist pivoting of the blade body <NUM> relative to the cutting disk <NUM> in response to normal cutting operations where the blade body <NUM> is striking and severing stalks of grass and weeds. Also, a relative increase in the mass of the cutting blade <NUM> can increase the momentum of the cutting blades <NUM> when the cutting blade assembly <NUM> (<FIG>) is in operation, which can reduce the amount of energy (such as battery power) required to maintain the cutting blade assembly <NUM> in operation.

Returning specifically to <FIG>, the blade body <NUM> defines a first cutting edge <NUM> that is configured to sever stalks of grass and weeds. The first cutting edge <NUM> can be defined by the first face <NUM>. In various embodiments, the first cutting edge <NUM> is mutually defined by the intersection of the first face <NUM> and a first edge plane <NUM> that extends from the second face <NUM> to the first face <NUM>. The first edge plane <NUM> defines a taper in the thickness T of the blade body from the second face <NUM> to the first cutting edge <NUM>. In various embodiments, the first cutting edge <NUM> is straight, meaning that the first cutting edge <NUM> extends along a straight line. The first cutting edge <NUM> generally intersects the distal end <NUM> of the cutting blade <NUM>, however the intersection can form a relatively small radius r<NUM>, such as currently depicted. In various embodiments, the first cutting edge <NUM> forms an acute angle α<NUM> with the distal end <NUM>. The first cutting edge <NUM> extends from the distal end <NUM> towards the proximal end <NUM>.

In various embodiments, the blade body <NUM> defines a second cutting edge <NUM> that is configured to sever stalks of grass and weeds. The second cutting edge <NUM> can be defined by the second face <NUM>. In various embodiments, the second cutting edge <NUM> is mutually defined by the intersection of the second face <NUM> and a second edge plane <NUM> that extends from the first face <NUM> to the second face <NUM>. The second edge plane <NUM> defines a taper in the thickness T of the blade body <NUM> from the first face <NUM> to the second face <NUM> at the second cutting edge <NUM>. In various embodiments, the second cutting edge <NUM> is straight. The second cutting edge <NUM> generally intersects the distal end <NUM> of the cutting blade <NUM>, however the intersection can form a relatively small radius r<NUM>. In various embodiments, the second cutting edge <NUM> forms an acute angle α<NUM> with the distal end <NUM>. The second cutting edge <NUM> extends from the distal end <NUM> towards the proximal end <NUM>.

In some embodiments, the second cutting edge <NUM> can be omitted. In various embodiments, only one of the first cutting edge <NUM> and the second cutting edge <NUM> is in severing engagement with grass/weeds during mower operation. However, in examples consistent with the currently-described embodiments, the cutting blade <NUM> is rotationally symmetric about a rotational axis xr parallel to the length direction of the cutting blade <NUM>. The rotational axis xr is central to the thickness T and width of the cutting blade <NUM>. If the first cutting edge <NUM> becomes dull or is subject to a replacement schedule, the cutting blade <NUM> can be detached from the cutting disk <NUM>, rotated <NUM>° about the rotational axis xr, and reattached to the cutting disk <NUM> so that the second cutting edge <NUM> is configured to be in severing engagement with the grass/weeds.

In various embodiments, the tool motor <NUM> (see <FIG>, for example) is configured to rotate its output shaft <NUM> and therefore, the cutting blade assembly <NUM>, in a first direction about the tool axis xt such that the first cutting edge <NUM> is in severing engagement with grass/weeds during mower operation. In many such embodiments, the tool motor <NUM> is configured to rotate its output shaft <NUM> and therefore, the cutting blade assembly <NUM>, in a second, opposite direction about the tool axis xt such that the second cutting edge <NUM> is in severing engagement with grass/weeds during mower operation. Such a configuration can advantageously extend the time between service intervals because the cutting life of the blades is essentially doubled.

In various embodiments a controller such as described above can be in operative communication with the motor to control the direction of rotation of the output shaft <NUM>. In some embodiments, the controller can be configured to provide a command to the motor to reverse the rotation of the output shaft <NUM>. Such a command can be provided upon identifying that rotation of the output shaft <NUM> in a first direction has exceeded a threshold length of time, for example. In such embodiments, the mower can advantageously ensure that a relatively sharp cutting blade is in use. In some embodiments, the controller can be configured to provide a command to the motor to reverse the rotation of the output shaft <NUM> upon receiving input from a user through a user interface such as a control panel or remote computer. In some embodiments, the direction of rotation of the output shaft <NUM> is selectable by a user.

In various embodiments, the first cutting edge <NUM> and the second cutting edge <NUM> diverge from each other as they approach the distal end <NUM> of the cutting blade <NUM>. The oblique orientation of the first cutting edge <NUM> (and the second cutting edge <NUM>) relative to the length direction of the blade body <NUM> can increase the cutting capacity of the edges <NUM>, <NUM> compared to a cutting edge that is parallel to the length of the blade body <NUM>.

Claim 1:
An autonomous ground working vehicle (<NUM>) comprising:
a chassis (<NUM>);
wheels (<NUM>, <NUM>) coupled to the chassis (<NUM>);
a motor housing (<NUM>) coupled to the chassis (<NUM>), the motor housing (<NUM>) defining a motor cavity (<NUM>) extending in an axial direction, the motor housing (<NUM>) comprising a first inner housing portion (<NUM>) having a first helical thread (<NUM>) about the motor cavity (<NUM>) and a second inner housing portion (<NUM>) having a second helical thread (<NUM>) about the motor cavity (<NUM>) that engages the first helical thread (<NUM>), wherein the first inner housing portion (<NUM>) has a motor mounting surface (<NUM>) and is axially translatable relative to the chassis (<NUM>) and rotatably fixed relative to the chassis (<NUM>), and the second inner housing portion (<NUM>) is rotatable relative to the chassis (<NUM>) and axially fixed relative to the chassis (<NUM>), wherein the first inner housing portion (<NUM>) comprises:
an inner body (<NUM>) extending from the motor mounting surface (<NUM>) towards the second inner housing portion (<NUM>), wherein the inner body (<NUM>) defines the first helical thread (<NUM>); and
an outer body (<NUM>) extending axially from the motor mounting surface (<NUM>) towards the second inner housing portion (<NUM>), wherein the outer body (<NUM>) and the inner body (<NUM>) define an annular gap (<NUM>) that receives a portion of the second inner housing portion (<NUM>);
a tool motor (<NUM>) fixed to the motor mounting surface (<NUM>), the tool motor (<NUM>) having an output shaft (<NUM>) extending in a first direction; and
a tool (<NUM>) fixed to the output shaft (<NUM>).