WO2024173652A1

WO2024173652A1 - Dual operating lever lawn care vehicle with one hand operation capability

Info

Publication number: WO2024173652A1
Application number: PCT/US2024/015948
Authority: WO
Inventors: Benjamyn A. THOMPSON; Adam B. WATSON
Original assignee: Husqvarna Ab
Priority date: 2023-02-15
Filing date: 2024-02-15
Publication date: 2024-08-22

Abstract

A steering assembly for a riding lawn care vehicle including a first drive wheel and a second drive wheel powered by a first drive motor and a second drive motor may include a first steering lever operably coupled to the first drive motor a second steering lever operably coupled to a second drive motor, a differential locking assembly and a mode controller. The differential locking assembly may be operably coupled to the first and second motors to define a first mode in which unmatched positioning of the first and second steering levers causes turning of the riding lawn care vehicle based on different drive speed control inputs to each of the first and second drive motors, respectively, and a second mode in which matched drive speed control is provided to both the first and second drive motors based on a position of only one of the first and second steering levers. The mode controller may be operably coupled to the differential locking assembly to enable transition between the first mode and the second mode.

Description

DUAL OPERATING LEVER LAWN CARE VEHICLE WITH ONE HAND OPERATION CAPABILITY

TECHNICAL FIELD

Example embodiments generally relate to lawn care vehicles and, more particularly, to riding lawn care vehicles having independently operated drive wheels.

BACKGROUND

Lawn care tasks are commonly performed using various tools and/or machines that are configured for the performance of corresponding specific tasks. Certain tasks, like grass cutting, are typically performed by lawn mowers. Lawn mowers themselves may have many different configurations to support the needs and budgets of consumers. Walk-behind lawn mowers are typically compact, have comparatively small engines, and are relatively inexpensive. Meanwhile, at the other end of the spectrum, riding lawn mowers, such as lawn tractors, can be quite large. Riding lawn mowers can sometimes also be configured with various functional accessories (e.g., trailers, tillers, and/or the like) in addition to grass cutting components. Riding lawn mowers provide the convenience of a riding vehicle as well as a typically larger cutting deck as compared to a walk-behind model.

By their very nature, riding lawn mowers include steering assemblies that are used to direct the movement of the riding lawn mowers. The steering assemblies often take the familiar form of a steering wheel. However, handlebar assemblies have also been used in some cases. In either of these cases, the operator may grasp either the wheel or handlebars with one hand and control steering effectively while using the other hand to operate a working assembly, accessory, or make selections on a control panel. Thus, for example, the bag dump lever, which may be behind the operator, may be actuated with one hand while the operator otherwise continues to control steering with the other hand on the wheel or handlebars.

More recently, some mowers have been provided with very short (e.g., near zero) turning radiuses. Such mowers have employed separate steering levers that interface with the drive wheels on each respective side of the mower. When these separate steering levers are employed, it is common for a drive wheel on each side of the vehicle to be controlled by a corresponding lever on the same side of the vehicle. The drive wheel is then driven forward or backward based on whether the corresponding steering lever is also pushed forward or pulled backward toward the operator. Thus, manual control of both levers simultaneously is typically required while the vehicle is moving. Any operation that involves the removal of one hand from one of the steering levers would therefore typically require the operator to stop the vehicle (returning both steering levers to the neutral position) to remove one hand to actuate the working assembly, lever, or control panel actuator. In the example above, the operator would stop the vehicle (again by returning both steering levers to the neutral position) to then release one steering lever and use that hand to operate the bag dump lever.

This restriction on the operation of riding lawn care vehicles that employ dual steering levers would be desirable to overcome. Some example embodiments of the present invention provide just such an opportunity, as described in greater detail below.

BRIEF SUMMARY OF SOME EXAMPLES

In one example embodiment, a riding lawn care vehicle is provided. The riding lawn care vehicle may include a frame to which at least a first drive wheel and a second drive wheel of the riding lawn care vehicle are attachable, a first drive motor operably coupled to the first drive wheel to provide power thereto in forward and reverse driving directions, a second drive motor operably coupled to the second drive wheel to provide power thereto in the forward and the reverse driving directions, a steering assembly and a mode controller. The steering assembly may include a first steering lever and a second steering lever. The first and second steering levers may be operably coupled to the first and second drive motors, respectively. The steering assembly may further include a differential syncing assembly operably coupled to the first and second motors to define a first mode in which unmatched positioning of the first and second steering levers causes turning of the riding lawn care vehicle based on different drive speed control inputs to each of the first and second drive motors, respectively, and a second mode in which matched drive speed control is provided to both the first and second drive motors based on a position of only one of the first and second steering levers. The mode controller may be operably coupled to the differential locking assembly to enable transition between the first mode and the second mode.

In another example embodiment, a steering assembly for a riding lawn care vehicle including a first drive wheel and a second drive wheel powered by a first drive motor and a second drive motor may be provided. The steering assembly may include a first steering lever operably coupled to the first drive motor a second steering lever operably coupled to a second drive motor, a differential locking assembly and a mode controller. The differential locking assembly may be operably coupled to the first and second motors to define a first mode in which unmatched positioning of the first and second steering levers causes turning of the riding lawn care vehicle based on different drive speed control inputs to each of the first and second drive motors, respectively, and a second mode in which matched drive speed control is provided to both the first and second drive motors based on a position of only one of the first and second steering levers. The mode controller may be operably coupled to the differential locking assembly to enable transition between the first mode and the second mode.

Some example embodiments may improve an operator's ability to operate the lawn care vehicle with one hand. The user experience associated with operating the riding lawn care vehicle may therefore be improved.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Having thus described some embodiments of the present invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

FIG. 1 A illustrates a perspective view of a riding lawn care vehicle according to an example embodiment;

FIG. IB illustrates a top view of the riding lawn care vehicle according to an example embodiment;

FIG. 2 illustrates a perspective view of a steering assembly with steering levers positioned to be pulled back for rearward propulsion according to an example embodiment;

FIG. 3 illustrates a block diagram of some steering assembly components according to an example embodiment; and

FIG. 4 illustrates a block diagram of a steering assembly in accordance with an example embodiment.

DETAILED DESCRIPTION

Some example embodiments now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all example embodiments are shown. Indeed, the examples described and pictured herein should not be construed as being limiting as to the scope, applicability, or configuration of the present disclosure. Rather, these example embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout. Furthermore, as used herein, the term “or” is to be interpreted as a logical operator that results in true whenever one or more of its operands are true. As used herein, the phrase “operable coupling” and variants thereof should be understood to relate to direct or indirect connection that, in either case, enables functional interconnection of components that are operably coupled to each other.

Some example embodiments may improve the ability of an operator to apply, engage, actuate, and/or otherwise activate any levers, controllers, buttons or other actuators that require the operator to take one hand of the steering levers of a dual steering lever riding lawn care vehicle without requiring the operator to stop operation of the vehicle. In this regard, example embodiments may provide a steering assembly that can be placed in a differential lock mode that directs the motor controller associated with one drive wheel to act as a follower and be synchronized with the motor controller of the other drive wheel, which acts as a leader, regardless of the corresponding steering lever position of the follower. Moreover, some example embodiments may provide an actuator for entry into (and exit out of) the differential lock mode on one (or both) of the steering levers proximate to the operator’s normal grasping position so that the operator can use his/her hand on the corresponding steering lever to actuate the differential lock mode and enable the other hand to be removed. While in the differential lock mode, the follower motor controller will match the speed or revolutions per minute (RPM) of the motor controller of the leader. As such, the described assemblies and structures create a more intuitive, and less restricted, operator experience than the current typical way of operating the steering levers.

FIG. 1, which includes FIGS. 1 A and IB, illustrates a riding lawn care vehicle 10 according to an example embodiment. FIG. 1 A illustrates a perspective view of the riding lawn care vehicle 10, and FIG. IB illustrates a top view of the riding lawn care vehicle 10 according to an example embodiment. In some embodiments, the riding lawn care vehicle 10 may include a seat 20 that may be disposed at a center, rear, or front portion of the riding lawn care vehicle 10. The riding lawn care vehicle 10 may also include a steering assembly 30 (e.g., a set of steering levers or the like) functionally connected to wheels 31 and/or 32 of the riding lawn care vehicle 10 to allow the operator to steer the riding lawn care vehicle 10.

FIG. 2 illustrates a perspective view of a steering assembly with steering levers positioned to be pulled back for rearward propulsion according to an example embodiment. Referring to FIGS. 1 and 2, the operator may sit on the seat 20, which may be disposed to the rear of the steering assembly 30 to provide input for steering of the riding lawn care vehicle 10 via the steering assembly 30. However, some models may be stand-up models that eliminate the seat 20. If the seat 20 is eliminated, the operator may stand at an operator station proximate to the steering assembly 30. In an example embodiment, the steering assembly 30 may include separately operable steering levers 34 shown specifically in FIG. IB and FIG. 2.

The riding lawn care vehicle 10 may also include a cutting deck 40 having at least one cutting blade (e.g., three cutting blades) mounted therein. The cutting deck 40 may be positioned substantially rearward of a pair of front wheels 31 and substantially forward of a pair of rear wheels 32 in a position to enable the operator to cut grass using the cutting blade(s) when the cutting blade(s) are rotated below the cutting deck 40 when the cutting deck 40 is in a cutting position. However, in some alternative examples, the cutting deck 40 may be positioned in front of the front wheels 31. In some embodiments, a footrest 42 may also be positioned above the cutting deck 40 forward of the seat 20 to enable the operator to rest his or her feet thereon while seated in the seat 20. In embodiments that do not include the seat 20, the footrest 42 may form the operator station from which a standing operator controls the riding lawn care vehicle 10. When operating to cut grass, the grass clippings may be captured by a collection system, mulched, or expelled from the cutting deck 40 via either a side discharge or a rear discharge.

In the pictured example embodiment, an engine 50 of the riding lawn care vehicle 10 is disposed to the rear of a seated operator. However, in other example embodiments, the engine 50 could be in different positions such as in front of or below the operator. As shown in FIG. 1, the engine 50 may be operably coupled to one or more of the wheels 31 and/or 32 to provide drive power for the riding lawn care vehicle 10. The engine 50, the steering assembly 30, the cutting deck 40, the seat 20, and other components of the riding lawn care vehicle 10 may be operably connected (directly or indirectly) to a frame 60 of the riding lawn care vehicle 10. The frame 60 may be a rigid structure configured to provide support, connectivity, and/or interoperability functions for various ones of the components of the riding lawn care vehicle 10.

In some example embodiments, the steering assembly 30 may be embodied as an assembly of metallic and/or other rigid components that may be welded, bolted, and/or otherwise attached to each other and operably coupled to the wheels of the riding lawn care vehicle 10 to which steering inputs are provided (e.g., rear wheels 32). For example, the steering assembly 30 may include or otherwise be coupled with hydraulic motors that independently power one or more drive wheels (e.g., rear wheels 32) on each respective side of the riding lawn care vehicle 10. The steering levers 34 may be operable to move forward (i.e., in a direction opposite arrow 68 in FIG. 2) and rearward (i.e., in the direction shown by arrow 68 in FIG. 2) while in the inboard position (shown in both FIGS. 1 and 2). When a steering lever 34 is pushed forward (e.g., away from the operator an opposite the direction of arrow 68), the corresponding hydraulic motor may drive the corresponding wheel forward. When a steering lever 34 is pulled rearward (e.g., toward the operator as shown by the direction of arrows 68 in FIG. 2), the corresponding hydraulic motor may drive the corresponding wheel backward. Thus, when both steering levers 34 are pushed forward the same amount, the riding lawn care vehicle 10 travels forward in substantially a straight line because approximately the same amount of forward drive input is provided to each drive wheel. When both steering levers 34 are pulled back the same amount, the riding lawn care vehicle 10 travels backward (e.g., rearward) in substantially a straight line because approximately the same amount of rearward drive input is provided to each drive wheel. When one steering lever 34 is pushed forward and the other steering lever 34 is pulled back, the riding lawn care vehicle 10 begins to turn in a circle and/or spin. Steering right and left may be accomplished by providing uneven amounts of input to the steering levers 34. Other steering control systems may be employed in some alternative embodiments.

Although the steering levers 34 are generally moved forward (i.e., opposite the direction of the arrows 68 shown in FIG. 2) or backward (i.e., in the direction of the arrows 68 shown in FIG. 2) in any desirable combination while they are in the operating positions shown in FIGS. 1 and 2, it should be appreciated that the steering levers 34 may also be moved to an outboard position (e.g., in a non-operational state) by moving the steering levers 34 outwardly in the direction shown by arrows 70 in FIG. IB. In this regard, although the steering levers 34 are shown in the inboard (or operational) position in FIGS. 1 and 2, the steering levers 34 may be moved in the direction of arrows 70 (i.e., outboard) relative to their inboard position and into a non-operational position. In some cases, each of the steering levers 34 may be operably coupled to respective lever mounts 80 that may pivot to enable the steering levers 34 to move outwardly (e.g., to the outboard position) or inwardly (e.g., to an inboard and/or operating position). In some embodiments, when at least one (and sometimes both) of the steering levers 34 is pivoted outwardly, brakes may be applied and the operator may easily mount or dismount the riding lawn care vehicle 10 and sit in or leave the seat 20.

As seen in FIG. IB, the riding lawn care vehicle 10 may have a control panel 90, which may be disposed on either the right or left side of the seat 20 to be readily accessible to the operator while seated. As noted above, in order to actuate any buttons, levers or other actuators at the control panel 90 (or anywhere else on the riding lawn care vehicle 10), the operator will need to remove one of his/her hands (in this case the right hand) from a corresponding one of the steering levers 34. Since the respective lever mounts 80 are typically operably coupled to a biasing assembly that tends to return the steering levers 34 to a neutral position when not being pushed or pulled away from the neutral position by the operator, any activity that causes the operator to remove a hand from one of the steering levers 34 would normally necessarily return the released one of the steering levers 34 (in this case the right one) back to the neutral position. Thus, any movement of the other one of the steering levers 34 (in this case the left one) would necessarily cause the riding lawn care vehicle 10 to turn. There is quite simply no way to move either straight forward or straight back since one of the steering levers 34 (again, the right one in this example) is going to be left at the neutral position. Thus, to actuate control devices at the control panel 90 (or most other locations of the riding lawn care vehicle 10), the operator is typically forced to return both of the steering levers 34 to the neutral position, and not operate the riding lawn care vehicle 10 at all until such actuation of the other control devices has been completed.

To partially address this situation, a recent innovation for these types of riding lawn care vehicles has been to provide at least some controls directly on the steering levers 34. Thus, some controls otherwise normally provided on the control panel 90, which require Although not required, in some embodiments, one or more of the steering levers 34 may include an on stick control (OSC) 92. In FIG. 2, the OSC 92 is shown on the left one of the steering levers 34. However, the OSC 92 could alternatively be located on the right one of the steering levers 34, or an instance of the OSC 92 could be located on both steering levers 34.

The provision of the OSC 92 on one (or both) of the steering levers 34 may enable various electronic controls to be actuated during operation of the steering levers 34 since the operator is not required to remove the corresponding hand that presses buttons or actuates control features on the OSC 92 during such actuation. While this is a big improvement, it nevertheless does not provide a solution when the button, lever or other actuator happens to be located somewhere else. For a lever (e.g., a bag dump lever) that is located on the rear portion of the riding lawn care vehicle 10, for example, the operator still needs to stop operation of the vehicle, return the steering levers 34 to the neutral position, and then turn around and remove one hand from the steering levers 34 to actuate the bag dump lever. Example embodiments may provide a further improvement in this situation for the riding lawn care vehicle 10, which happens to be a so-called zero turn-type vehicle. However, it will further be appreciated that the solution described herein may be applied to any set of two (or more) independently driven motors on a lawn care vehicle with two or more drive elements. FIG. 3 illustrates a block diagram of some steering components of an example embodiment that addresses the situation described. As shown in FIG. 3, each one of the steering levers 34 may be operably coupled to a corresponding one of the lever mounts 80. The lever mounts 80 may be operably coupled to corresponding drive motors 100 that power respective ones of the drive wheels (e.g., the rear wheels 32). The drive motors 100 may, in some cases, have speed (or other control) inputs provided thereto be respective instances of a motor controller 110. A differential locking assembly 120 may be operably coupled to the drive motors 100 and/or the motor controllers 110 to, when activated, synchronize the drive speed of the drive motors 100 (e.g., via control of the motor controllers 110). Activation of the differential locking assembly 120 may, in some cases, be controlled in turn by a mode controller 130.

The mode controller 130 may be a button, lever or other actuator that initiates a differential lock mode when actuated (or activated). Thus, for example, when the mode controller 130 is pushed, depressed, deflected, rotated, or otherwise actuated, the mode controller 130 may transition the differential locking assembly 120 into a locked mode or state. At all other times, i.e., when the mode controller 130 is not actuated, the differential locking assembly 120 may be in an unlocked mode or state.

In some embodiments, the mode controller 130 may be disposed at the OSC 92 of FIG. 2. In such cases, the mode controller 130 may conveniently be actuated by a finger or other portion of the corresponding hand of the operator on the corresponding one of the steering levers 34 without the operator having to remove his/her hand from the corresponding one of the steering levers 34. Thus, for example, the operator may be actively moving one or both of the steering levers 34, and may actuate the mode controller 130 at the OSC 92. The actuation of the mode controller 130 may cause the differential locking assembly 120 to transition or shift to the locked mode, and the differential locking assembly 120 may synchronize the drive speed of the drive motors 100 directly or indirectly (e.g., via the motor controllers 110). When in the locked mode, a designated one of the drive motors 100 may be designated as leader, and the other one of the drive motors 100 may be designated as follower. The position of the one of the steering levers 34 that is on the same side as the leader (or lead drive motor) will thereafter determine the speed or RPM of the follower (or following drive motor).

In the example of FIG. 2, where the OSC 92 is on the left one of the steering levers 34, the drive motor 100 on the left side would become the leader when in the locked mode, and the drive motor 100 on the right side would become the follower. However, if the OSC 92 were on the opposite one of the steering levers 34 (i.e., on the right side), then the right one of the drive motors 100 would become the leader, and the left one of the drive motors 100 would become the follower. In an example in which one instance of the OSC 92 was on the left and another instance of the OSC 92 was on the right one of the steering levers 34, selection of the mode controller 130 on either instance of the OSC 92 would designate the drive motor 100 on the same side of the mode controller 130 selected the leader and the drive motor 100 on the opposite side of the mode controller 130 selected the follower. In still other example embodiments, the mode controller 130 may be disposed at the control panel 90, or another part of the riding lawn care vehicle 10 (e.g., a foot pedal or hand operated lever/button).

Once a leader and follower are determined, the position of the steering lever 34 associated with the follower may, in some cases be irrelevant. The drive motor 100 of the follower will have a speed that matches the drive motor 100 of the leader, based on the position of the steering lever 34 of the leader. In most cases, the steering lever 34 of the follower will likely return to the neutral position (under influence of normal biasing forces) when released. However, as noted in greater detail below, the steering lever 34 of the follower could, in some cases, be made to move with the steering lever 34 of the leader as well.

In an example embodiment, the drive motors 100 may be electric motors that operate under control of respective instances of the motor controller 110. The motor controller 110 of each one of the drive motors 100 may convert a position of the corresponding one of the steering levers 34 into a corresponding input or control signal for the respective drive motor 100 on its same side. In those cases, the differential locking assembly 120 may simply, when in the unlocked state, allow each respective motor controller 110 to independently use the input or control signal from its corresponding one of the steering levers 34 to dictate the speed of the corresponding one of the drive motors 100. Meanwhile, when in the locked state, the differential locking assembly 120 may substitute the input or control signal for the drive motor 100 of the follower with the corresponding input or control signal that was generated by or for the drive motor 100 of the leader.

Thus, for example, in some embodiments, the input or control signals generated by the motor controllers 110 may be communicated to the differential locking assembly 120 instead of directly to the respective ones of the drive motors 100. The differential locking assembly 120 may then, based on the unlocked or locked state that is determined by the mode controller 130, provide the appropriate input or control signal to the drive motors 100 based on the control paradigm described above.

The drive motors 100 could, in some alternative embodiments, be other types of motors that may or may not operate under electronic control. When the drive motors 100 are not electronically controllable via the motor controllers 110, the differential locking assembly 120 may take another form to permit mechanical, hydraulic, or other means to be used to communicate input from the steering lever 34 on one side to the drive motor 100 on the opposite side to simulate similar functionality to that which is described above (as shown by the dashed lines from the differential locking assembly 120 to the drive motors 100 in FIG. 3).

As noted above, the steering levers 34 may generally be biased toward a neutral position whenever the operator does not manually overcome the biasing force to move the steering levers 34 forward or rearward from the neutral position. Thus, under normal circumstances, if the operator releases one of the steering levers 34 while in the locked state, the drive motor 100 that acts as follower will have matched speed to the drive motor 100 that acts as leader and the steering lever 34 of the follower will return to the neutral position. This will remain the situation, with the speed of the drive motor 100 that acts as follower matching the speed of the drive motor 100 that acts as leader based on the steering lever 34 position of the leader, and regardless of the steering lever 34 position of the follower for as long as the mode controller 130 remains actuated. However, release of the mode controller 130 may transition to the unlocked state, and if such transition is immediate, the input for the drive motor 100 that was follower in the locked state may (if the steering lever 34 thereof is not otherwise moved) immediately be transitioned to zero speed. If the steering lever 34 of the drive motor 100 that was leader in the locked state is currently pressed far forward or rearward, an immediate and significant turn could result. To prevent such an immediate and significant turn from resulting, a number of potential control augmentation strategies may be employed. Some examples of such strategies are described below in reference to FIGS. 4.

FIG. 4 illustrates a left drive wheel 200 and a right drive wheel 202 that are operably coupled to corresponding ones of a left drive motor 210 and a right drive motor 212. The left and right drive wheels 202 are examples of rear wheels 32 in FIGS. 1 A, IB and 3, and the right and left drive motors 210 and 212 are examples of the drive motors 100 in FIG. 3. The left drive motor 210 may be operably coupled to a left motor controller 220 and the right drive motor 212 may be operably coupled to a right motor controller 222. In this context, the left and right motor controllers 220 and 222 may be examples of the motor controllers 110 of FIG. 3.

In some embodiments, the left and right motor controllers 220 and 222 may each be operably coupled to differential locking assembly 230 (which may be an example of differential locking assembly 120 of FIG. 3). Mode control for the differential locking assembly 120 may be provided to transition between locked and unlocked modes via mode controller 240. When the mode controller 240 is actuated to initiate the locked mode, the right drive motor 212 may be operated at the same speed as the left drive motor 210 in the manner described above. However, rather than simply having the position of the right steering lever 256 be in the neutral position (or at least irrelevant) when the locked mode is active, the example of FIG. 4 may further also cause the steering levers to move in synchronization as well.

As shown in FIG. 4, the differential locking assembly 230 may be operably coupled to a steering lever sensor 250, which may determine a position of a left steering lever 254. In this example embodiment, the mode controller 240 may be provided at the left steering lever 254, and therefore in the locked mode, the left drive motor 210 may always be the leader, and the right drive motor 212 may always be the follower when the locked mode is entered. It should be appreciated, however, that the roles may be swapped if the mode controller 240 is put on the right steering lever 256, or both steering levers could have instances of the mode controller 240 and whichever one is actuated would dictate which drive motor becomes leader and follower, as described above.

In an example in which the left steering lever 254 is associated with the leader in all cases, it is only necessary to have the steering lever sensor 250 monitor a position of the left steering lever 254. However, if the mode controller 240 (or an instance thereof) is provided at the right steering lever 256 instead (or additionally), then the steering lever sensor 250 (or another instance thereof) may be located at the right steering lever 256.

Returning to this example in which the left steering lever 254 is associated with the leader in all cases, the steering lever sensor 250 may report to the differential locking assembly 230 as to the position of the left steering lever 254 in real time as such movements occur to provide a current position of the left steering lever 254 at all times. The differential locking assembly 230 may also be operably coupled to a servomotor 260 (or other electric motor) that may be operably coupled to the right steering lever 256. The servomotor 260 may be capable of displacing the right steering lever 256 from the neutral position based on a lever control signal 270 provided by the differential locking assembly 230. Meanwhile, the lever control signal 270 may be generated based on the determined position of the left steering lever 254 as indicated by the steering lever sensor 250. The servomotor 260 and the steering lever sensor 250 may together be portions of a repositioning assembly (or lever repositioning assembly) of an example embodiment.

Thus, for example, if the mode controller 240 is actuated to transition the differential locking assembly 230 to the locked mode (or state), then the left drive motor 210 is to be the leader and the right drive motor 212 is to be the follower in the locked mode. The steering lever sensor 250 may provide the differential locking assembly 230 with an indication of a current position of the left steering lever 254. The differential locking assembly 230 may then provide the lever control signal 270 to the servomotor 260 to move the right steering lever 256 to match the current position of the left steering lever 254. The servomotor 260 may then continuously operate to maintain the right steering lever 256 in a matched position to that of the left steering lever 254 through any repositioning of the left steering lever 254 based on the input provided by the steering lever sensor 250 for as long as the mode controller 240 remains actuated (in the locked mode). By matching the physical movement of the left and right steering levers 254 and 256, the positions thereof will also be matched when the mode controller 240 is released and the differential locking assembly 230 transitions to the unlocked state. This will prevent the immediate and significant turn that a prompt jump change in mode or state might otherwise cause.

In some embodiments, the differential locking assembly 230 may further include a ramp controller 280 including memory and processing circuitry configured to slow a transition of the lever control signal 270 from a signal value corresponding to the current position of the right steering lever 256 (when the mode change occurs) to the neutral position. The memory of the ramp controller 280 may store ramped speed data that may define how fast the position of the steering levers can be allowed to change in a given circumstance or situation (e.g., based on vehicle speed, angle of the operating surface, or other factors).

In some embodiments, the differential locking assembly 230 may generate a transition notification (e.g., a beep, flashing light, vibration, whistle or other audible, visible or haptic feedback mechanism) to inform the operator that the right steering lever 256 (in this example) is in transition from automatic repositioning using the servomotor 260 to the neutral position. The transition notification may therefore remind the operator can to take manual control of the corresponding one of the steering levers (i.e., the right steering lever 256 in this example).

In an example embodiment, the ramp controller 280 may also or alternatively control the speed of the follower drive motor (e.g., the right drive motor 212 in this example) when the follower drive motor transitions out of the locked mode (or state). In such an example, the ramp controller 280 may provide inputs to the corresponding motor controller (e.g., the right motor controller 222 in this example) that transitions out of follower mode in order to control the speed of the follower drive motor smoothly and slowly during the transition until the speed reaches zero when the corresponding steering lever reaches the neutral position, or until the operator grasps and positions the corresponding steering lever. In other words, the ramp controller 280 may be configured to control a rate of speed change from a first speed corresponding to the current position of the left steering lever 254 when the mode controller 240 is released to a second speed corresponding to the current position of the right steering lever 256 when the mode controller 240 is released (particularly if not the same).

As an alternative (or additionally), the differential locking assembly 230 may initiate a drive change delay, and a corresponding transition notification (similar to that described above) while the drive change delay is in effect. The drive change delay may define a period of time after release of the mode controller 240 to transition to the unlocked mode (or state) during which the differential locking assembly 230 continues to operate in the locked state to give the operator time to grasp and control the follower steering lever.

In still other embodiments, the differential locking assembly 230 may provide instructions (audibly or visually) for the operator to return both the left and right steering levers 254 and 256 to neutral after release of the mode controller 240 to transition to the unlocked mode. A return to neutral may be required before further inputs to the left and right steering levers 254 and 256 can be used to steering the riding lawn care vehicle 10 in such an example to ensure that the operator is cognizant of the mode change and ready to operate the riding lawn care vehicle 10 in the unlocked mode (i.e., with both hands on the left and right steering levers 254 and 256).

As an alternative to the servo example described in reference to FIG. 4, other mechanical or electrical control paradigms for matching steering lever positions in the locked mode may be employed. For example, mechanical linkages that are made or released in and out of the locked state may be employed.

Accordingly, some example embodiments may describe an improved riding lawn care vehicle, or a steering assembly for the same. The riding lawn care vehicle may include a frame to which at least a first drive wheel and a second drive wheel of the riding lawn care vehicle are attachable, a first drive motor operably coupled to the first drive wheel to provide power thereto in forward and reverse driving directions, a second drive motor operably coupled to the second drive wheel to provide power thereto in the forward and the reverse driving directions, a steering assembly and a mode controller. The steering assembly may include a first steering lever and a second steering lever. The first and second steering levers may be operably coupled to the first and second drive motors, respectively. The steering assembly may further include a differential locking assembly operably coupled to the first and second motors to define a first mode in which unmatched positioning of the first and second steering levers causes turning of the riding lawn care vehicle based on different drive speed control inputs to each of the first and second drive motors, respectively, and a second mode in which matched drive speed control is provided to both the first and second drive motors based on a position of only one of the first and second steering levers. The mode controller may be operably coupled to the differential locking assembly to enable transition between the first mode and the second mode.

The riding lawn care vehicle (or steering assembly) of some embodiments may include additional, optional features, and/or the features described above may be modified or augmented. Some examples of modifications, optional features and augmentations are described below. It should be appreciated that the modifications, optional features and augmentations listed below may each be added alone, or they may be added cumulatively in any desirable combination. For example, in some embodiments, the mode controller may disposed at one of the first or second steering levers. As an alternative, an instance of the mode controller may be disposed at each of the first and second steering levers. In an example embodiment, actuation of the mode controller to transition to the second mode may cause a speed of both the first and second drive motors to be determined based on a position of the first steering lever while the second steering lever is in a neutral position. In some cases, release of the mode controller to transition to the first mode may cause a speed of the second drive motor to be determined based on a position of the second steering lever. The differential locking assembly may also include a ramp controller configured to control a rate of speed change from a first speed corresponding to the position of the first steering lever when the mode controller is released to a second speed corresponding to the position of the second steering lever when the mode controller is released. In an example embodiment, the differential locking assembly may include processing circuitry configured to provide a transition notification using visual, audible or haptic feedback to indicate a time delay after release of the mode controller which, when expired, will cause speed of the second drive motor to be determined based on a position of the second steering lever instead of the first steering lever. Alternatively or additionally, the differential locking assembly may include processing circuitry configured to provide a transition notification using visual, audible or haptic feedback to indicate a time period after release of the mode controller which, until expired, will prevent any speed control inputs to the first and second drive motors until both the first and second steering levers are returned to a neutral position. In some embodiments, the first drive motor and the second drive motor may each be respective instances of an electric motor, and the differential locking assembly may control speed of the first and second drive motors via input to a first motor controller operably coupled to the first drive motor and a second motor controller operably coupled to the second drive motor, respectively. In an example embodiment, the differential locking assembly may be operably coupled to a servomotor and a steering lever position sensor. The servomotor may be operably coupled to the second steering lever, and the steering lever position sensor may be disposed to determine a position of the first steering lever. In the second mode, the servomotor may displace (or carry) the second steering lever away from the neutral position to match a position of the first steering lever based on input from the steering lever position sensor. In some cases, actuation of the mode controller to transition to the second mode may cause a speed of both the first and second drive motors to be determined based on a position of the first steering lever while the second steering lever is moved by a repositioning assembly to match a position of the first steering lever. In some cases, the riding lawn care vehicle may be a zero turn mower.

Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing descriptions and the associated drawings describe exemplary embodiments in the context of certain exemplary combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. In cases where advantages, benefits, or solutions to problems are described herein, it should be appreciated that such advantages, benefits, and/or solutions may be applicable to some example embodiments, but not necessarily all example embodiments. Thus, any advantages, benefits, or solutions described herein should not be thought of as being critical, required, or essential to all embodiments or to that which is claimed herein. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

THAT WHICH IS CLAIMED:

1. A riding lawn care vehicle comprising: a frame to which at least a first drive wheel and a second drive wheel of the riding lawn care vehicle are attachable; a first drive motor operably coupled to the first drive wheel to provide power thereto in forward and reverse driving directions; a second drive motor operably coupled to the second drive wheel to provide power thereto in the forward and the reverse driving directions; a steering assembly comprising a first steering lever and a second steering lever, wherein the first and second steering levers are operably coupled to the first and second drive motors, respectively, the steering assembly further comprising a differential locking assembly operably coupled to the first and second motors to define: a first mode in which unmatched positioning of the first and second steering levers causes turning of the riding lawn care vehicle based on different drive speed control inputs to each of the first and second drive motors, respectively, and a second mode in which matched drive speed control is provided to both the first and second drive motors based on a position of only one of the first and second steering levers; and a mode controller operably coupled to the differential locking assembly to enable transition between the first mode and the second mode.

2. The riding lawn care vehicle of claim 1, wherein the mode controller is disposed at one of the first or second steering levers.

3. The riding lawn care vehicle of claim 1, wherein an instance of the mode controller is disposed at each of the first and second steering levers.

4. The riding lawn care vehicle of claim 1, wherein actuation of the mode controller to transition to the second mode causes a speed of both the first and second drive motors to be determined based on a position of the first steering lever while the second steering lever is in a neutral position.

5. The riding lawn care vehicle of claim 4, wherein release of the mode controller to transition to the first mode causes a speed of the second drive motor to be determined based on a position of the second steering lever, and wherein the differential locking assembly comprises a ramp controller configured to control a rate of speed change from a first speed corresponding to the position of the first steering lever when the mode controller is released to a second speed corresponding to the position of the second steering lever when the mode controller is released.

6. The riding lawn care vehicle of claim 4, wherein the differential locking assembly comprises processing circuitry configured to provide a transition notification using visual, audible or haptic feedback to indicate a time delay after release of the mode controller which, when expired, will cause speed of the second drive motor to be determined based on a position of the second steering lever instead of the first steering lever.

7. The riding lawn care vehicle of claim 4, wherein the differential locking assembly comprises processing circuitry configured to provide a transition notification using visual, audible or haptic feedback to indicate a time period after release of the mode controller which, until expired, will prevent any speed control inputs to the first and second drive motors until both the first and second steering levers are returned to a neutral position.

8. The riding lawn care vehicle of claim 1, wherein the first drive motor and the second drive motor are each respective instances of an electric motor, and wherein the differential locking assembly controls speed of the first and second drive motors via input to a first motor controller operably coupled to the first drive motor and a second motor controller operably coupled to the second drive motor, respectively.

9. The riding lawn care vehicle of claim 1, wherein the differential locking assembly is operably coupled to a servomotor and a steering lever position sensor, wherein the servomotor is operably coupled to the second steering lever, wherein the steering lever position sensor is disposed to determine a position of the first steering lever, and wherein, in the second mode, the servomotor displaces the second steering lever away from the neutral position to match a position of the first steering lever based on input from the steering lever position sensor.

10. The riding lawn care vehicle of claim 1, wherein actuation of the mode controller to transition to the second mode causes a speed of both the first and second drive motors to be determined based on a position of the first steering lever while the second steering lever is moved by a repositioning assembly to match a position of the first steering lever.

11. The riding lawn care vehicle of any of claims 1 to 10, wherein the riding lawn care vehicle is a zero turn mower.

12. A steering assembly for a riding lawn care vehicle comprising a first drive wheel and a second drive wheel powered by a first drive motor and a second drive motor, the steering assembly comprising: a first steering lever operably coupled to the first drive motor; a second steering lever operably coupled to a second drive motor; and a differential locking assembly operably coupled to the first and second motors to define: a first mode in which unmatched positioning of the first and second steering levers causes turning of the riding lawn care vehicle based on different drive speed control inputs to each of the first and second drive motors, respectively, and a second mode in which matched drive speed control is provided to both the first and second drive motors based on a position of only one of the first and second steering levers; and a mode controller operably coupled to the differential locking assembly to enable transition between the first mode and the second mode.

13. The steering assembly of claim 12, wherein the mode controller is disposed at one of the first or second steering levers.

14. The steering assembly of claim 12, wherein an instance of the mode controller is disposed at each of the first and second steering levers.

15. The steering assembly of claim 12, wherein actuation of the mode controller to transition to the second mode causes a speed of both the first and second drive motors to be determined based on a position of the first steering lever while the second steering lever is in a neutral position.

16. The steering assembly of claim 15, wherein release of the mode controller to transition to the first mode causes a speed of the second drive motor to be determined based on a position of the second steering lever, and wherein the differential locking assembly comprises a ramp controller configured to control a rate of speed change from a first speed corresponding to the position of the first steering lever when the mode controller is released to a second speed corresponding to the position of the second steering lever when the mode controller is released.

17. The steering assembly of claim 15, wherein the differential locking assembly comprises processing circuitry configured to provide a transition notification using visual, audible or haptic feedback to indicate a time delay after release of the mode controller which, when expired, will cause speed of the second drive motor to be determined based on a position of the second steering lever instead of the first steering lever.

18. The steering assembly of claim 15, wherein the differential locking assembly comprises processing circuitry configured to provide a transition notification using visual, audible or haptic feedback to indicate a time period after release of the mode controller which, until expired, will prevent any speed control inputs to the first and second drive motors until both the first and second steering levers are returned to a neutral position.

19. The steering assembly of claim 12, wherein the first drive motor and the second drive motor are each respective instances of an electric motor, and wherein the differential locking assembly controls speed of the first and second drive motors via input to a first motor controller operably coupled to the first drive motor and a second motor controller operably coupled to the second drive motor, respectively.

20. The steering assembly of claim 12, wherein the differential locking assembly is operably coupled to a servomotor and a steering lever position sensor, wherein the servomotor is operably coupled to the second steering lever, wherein the steering lever position sensor is disposed to determine a position of the first steering lever, and wherein, in the second mode, the servomotor displaces the second steering lever away from the neutral position to match a position of the first steering lever based on input from the steering lever position sensor.

21. The steering assembly of claim 12, wherein actuation of the mode controller to transition to the second mode causes a speed of both the first and second drive motors to be determined based on a position of the first steering lever while the second steering lever is moved by a repositioning assembly to match a position of the first steering lever.