US20210289708A1 - Battery-operated electric mower - Google Patents

Abstract

A battery-operated electric mower having a chassis that supports at least an operator support and a first and second drive wheel, each drive wheel respectively connected to one of a first and a second drive wheel motor. The first drive wheel motor may be connected to the first drive wheel by a first gear mechanism, which may include a first system of planetary gears, and the second drive wheel motor may be connected the second drive wheel by a second gear mechanism, which may include a second system of planetary gears. The chassis also supports a battery pack positioned, at least in part, within the same horizontal plane as at least one of the drive wheel motors. The battery may be positioned, at least in part, between the first drive wheel motor and the second drive wheel motor, significantly lowering the mower's center of gravity.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a continuation of U.S. patent application Ser. No. 16/522,823 filed on Jul. 26, 2019 and issued as U.S. Pat. No. 11,032,973 on Jun. 15, 2021, the disclosure of which is incorporated herein by reference in entirety for all purposes.
FIELD
• This invention relates to machinery for lawn care, and in particular to battery-operated electric lawn mowers.
BACKGROUND
• Gasoline mowers have been used extensively to address lawn care needs. Unfortunately, gasoline mowers have numerous disadvantages. More particularly, internal combustion engines produce significant emissions and pollutants into the air. In addition, they require several fluids to operate, which over time, can result in a leakage of harmful fluids into the environment.
• Electric mowers have been introduced to address many of these issues. Unfortunately, current electric mower designs also include certain drawbacks. More particularly, many require use of an AC voltage power cord, which severally limits their range. Alternatively, some electric mowers use batteries as a power source. However, such batteries add weight to the mower, and many have low power to weight ratios, which can generate a need, in some instances, for heavy and bulky battery packs to sufficiently power the mower. As such, the positioning of a battery-operated electric mower's battery packs can significantly impact the location of the mower's center of gravity.
• FIGS. 1 and 2 show the positioning of a series of battery packs in a prior artelectric mower2, described in U.S. Pat. No. 10,130,037.FIG. 1 shows a partial rear elevation view of the prior artelectric mower2, with some elements omitted for clarity. Theelectric mower2 has achassis12, withdrive wheels22 positioned on each side of thechassis12 and two electricdrive wheel motors42 positioned between thedrive wheels22, eachdrive wheel motor42 mechanically coupled to one of thedrive wheels22 by agear reduction axle44. A plurality ofbattery packs26 rest on abattery floor62 located in an elevated position above thedrive wheel motors42 andgear reduction axles44. Thus, the height of thebattery packs26 with respect to a ground surface is limited in a downward direction by the presence of thedrive wheel motors42 and thegear reduction axles44.FIG. 2 shows a partial bottom view of the same prior art electric mower shown inFIG. 1, with some elements omitted for clarity. Here again, thedrive wheel motors42 andgear reduction axles44 are shown positioned between thedrive wheels22, underneath thebattery packs26. Thebattery floor62 has been omitted to reveal the plurality ofbattery packs26.
BRIEF SUMMARY OF THE INVENTION
• With respect to mowers, a lower center of gravity is generally more desirable than a higher center of gravity. Lowering the center of gravity, among other things, can increase the overall stability of the mower and the bank angle at which the mower may safely travel without overturning. It is additionally beneficial for a mower to be compact, as increased compactness may, among other things, increase the maneuverability of a mower during operation and the storability of a mower post operation. Therefore, structuring a battery-powered electric mower to house battery packs at a lower height relative to the ground surface can be desirable, as can structuring the mower to house the battery packs in a more forward position with respect to the front of the mower.
• In certain aspects, the present invention provides a battery-powered mower with a lowered center of gravity. In accordance with some forms of the invention, the batteries are configured to achieve the lowered center of gravity. Accordingly, in one embodiment, the present invention provides a battery-operated mower that includes a first and a second drive wheel connected to a chassis. An operator support for supporting an operator is also connected to the chassis. A first drive wheel motor is connected to the first drive wheel, and a second drive wheel motor is connected to the second drive wheel. A battery pack, supported by the chassis, is positioned at least in part between the first drive wheel motor and the second drive wheel motor.
• In another embodiment, the invention provides a battery-operated mower, having a chassis. A drive wheel motor is connected to an exterior portion of the chassis. A gear mechanism is mechanically coupled to the drive wheel motor. And a drive wheel is connected to the gear mechanism. Additionally, a battery pack is electrically connected to the drive wheel motor. The battery pack is positioned at least in part within the same horizontal plane as the drive wheel motor.
• In a further embodiment, the invention provides a battery-powered mower, including a chassis, with an operator support for supporting an operator connected to the chassis. Further, a first electric drive wheel motor is secured to a first exterior surface of the chassis. A first planetary gear reduction box, including a first system of planetary gears, is mechanically coupled to the first electric drive wheel motor, and a first drive wheel is secured to the first planetary gear reduction box. The first drive wheel surrounds at least a portion of the first electric drive wheel motor and at least a portion of the first planetary gear reduction box. Additionally, a second electric drive wheel motor is secured to a second exterior surface of the chassis. A second planetary gear reduction box, including a second system of planetary gears, is mechanically coupled to the second electric drive wheel motor. And a second drive wheel is secured to the second planetary gear reduction box. The second drive wheel surrounds at least a portion of the second electric drive wheel motor and at least a portion of the second planetary gear reduction box.
• Other objects and advantages of the present disclosure will become apparent hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
• Embodiments of the battery-operated electric mower are disclosed with reference to the accompanying exemplary drawings, which are for illustrative purposes. Various portions or components of the apparatus may be omitted from illustration in one or more FIGS. to improve clarity or to provide a view of underlying components. The battery-operated electric mower is not limited in application to the details of construction or the arrangement of the components illustrated in the drawings. The battery-operated electric mower is capable of other embodiments or of being practiced or carried out in various other ways. In the drawings:
• FIG. 1 is a rear elevation view of a prior art mower with various portions removed for clarity.
• FIG. 2 is a partial bottom view of the prior art mower ofFIG. 1 with various portions removed for clarity.
• FIG. 3 is a top front perspective view of a mower, according to one embodiment of the present disclosure.
• FIG. 4 is a top rear perspective view of the mower ofFIG. 3.
• FIG. 5 is a top plan view of the mower ofFIG. 3.
• FIG. 6 is a front elevation view of the mower ofFIG. 3.
• FIG. 7 is a left side elevation view of the mower ofFIG. 3.
• FIG. 7A is an enlarged left side elevation view of the drive wheel and gear reduction box shown inFIG. 7.
• FIG. 7B is a left side elevation view of the mower ofFIG. 7 with the left-side drive wheel and select parts of the chassis removed to show the battery packs.
• FIG. 8 is a bottom rear perspective view of the mower ofFIG. 3.
• FIG. 9 is a bottom plan view of the mower ofFIG. 3 with select parts of the chassis removed to show the battery packs.
• FIG. 10 is a rear elevation view of the mower ofFIG. 3.
• FIG. 11 is a cross-sectional rear elevation view of the mower ofFIG. 7 taken along line11-11 ofFIG. 7.
• FIG. 12 is a sectional top perspective view of the mower ofFIG. 7 taken along line12-12 ofFIG. 7.
• FIG. 13 is an enlarged cross-sectional rear elevation view of the left-side drive wheel and associated parts of the mower shown inFIG. 11.
• FIG. 14 is an enlarged cross-sectional view of the left-side gear reduction box, drive wheel motor, and associated parts of the mower ofFIG. 7, taken along line11-11.
DETAILED DESCRIPTION
• Referring toFIGS. 3-12, numerous perspective and elevation views of a battery-poweredelectric mower102 are provided, as described above. For reference, a rear104, aright side106, aleft side108, and a front110 are identified inFIG. 3.
• Themower102 includes achassis112 that consists of numerous structural members secured together to form a framework (i.e., a frame) for interconnecting various components of themower102, such components including but not limited to amower deck114, anoperator support116, a right sideoperator control panel118, a left sideoperator control panel120, a plurality ofdrive wheels122, and a plurality of frontsupport wheel assemblies124 that each may include a swivel mount and a wheel. Thechassis112 also houses one or more battery packs126 (FIGS. 3-5, 7B, and 9-12) for powering various electrical components of the mower, for example, drive wheel motors, blade motors, etc. In the illustrated embodiment, themower102 includes six battery packs126. However, in other embodiments, more or fewer battery packs126 may be included, based on factors such as the power output of a givenbattery pack126 and the power needs of a givenelectric mower102.
• In a least some embodiments, themower102 may include one or moreoperator control panels118,120 configured to provide a plurality of operator actuatable controls and annunciators, for example, for controlling main power, engaging cutting blade operations, adjusting the deck height, etc. In at least some embodiments, theseoperator control panels118,120 are located on opposite sides of theoperator support116, within easy reach of an operator. In the illustrated embodiment, theoperator support116 is shown as a sitting chair, although in other embodiments, theoperator support116 may be one of various other types of supports, for example, a standing pad, and the position of theoperator control panels118,120 may be accordingly adjusted, if necessary, to maintain operator accessibility.
• Referring toFIG. 5, in some embodiments, an ON/OFFkey switch128 may be provided on one of theoperator control panels118,120 to direct power from the battery packs126 to the electrical components of themower102. In the present embodiment, the ON/OFFkey switch128 is shown on the left sideoperator control panel120. As an alternative to using a key switch, in some embodiments, the power may be controlled from atouchscreen129. In certain embodiments, thetouch screen129 may produce a keypad when activated (for example, by the push of a button), and power to themower102 may be triggered by the entering of a particular code onto the keypad. In alternative embodiments, the keypad may be a separate element from thetouch screen129. Thetouch screen129 may further relate information with regard to the battery packs126, such as the state of charge (similar to a fuel gauge on a gas lawn mower), the time and/or percent remaining in the battery, and/or individual battery cell voltages and/or temperatures. Additionally, thetouch screen129 may relay to the operator service reminders, current (amp) usage, average current draw, drive speed position (high and low range), blade speed (high and low), lights (on and off), diagnostic information relating to potential faults in the system, and/or service reminders.
• Thedeck114 provides a sturdy structure for which to mount other components, such as a plurality ofelectric blade motors130, each having arespective cutting blade132, with eachcutting blade132 secured to the output shaft of arespective blade motor130. In some embodiments, the battery packs126 supply power to theblade motors130. Theblade motors130 each includemotor casings134, which are shown protruding through the top of thedeck114. Thedeck114 may also include a plurality of free-wheel support rollers136 for support of the deck as the mower moves over terrain.
• In at least some embodiments, mower steering may be provided by one or more actuators operable by an operator to signal whether the operator desires to steer right or left. In the illustrated embodiment, themower102 includes aright control actuator138 and aleft control actuator140. As illustrated, theactuators138,140 can be shaped as movable lap bars pivotably secured to thechassis112, while in other embodiments, the actuators can take various other forms, including a single arm capable of actuation to the left or right, or a pair of foot operated actuators. In other embodiments still, steering mechanisms other than actuators may be utilized. In an embodiment including actuator steering, movement of the right or leftcontrol actuator138,140 forward or backward may communicate to at least one drive wheel controller (not shown) to signal an electricdrive wheel motor142 to rotate acorresponding drive wheel122 forward or backward. If one of thecontrol actuators138,140 is not actuated, while the other is actuated, one of thedrive wheels122 will not rotate, thereby allowing for zero-turn capability. In certain embodiments, the drive wheel controllers may also provide power received from the battery packs126 to the electricdrive wheel motors142, and thus, provide the travel speed for themower102. In at least some embodiments, the electricdrive wheel motors142 are P/N E3258-420, as manufactured by Auburn Gear, LLC, located in Auburn, Ind.
• Referring toFIGS. 11-14, the electricdrive wheel motor142 is mechanically coupled to agear reduction box144. As shown in detail inFIG. 14, astator146 of the electricdrive wheel motor142 turns ashaft148 that axially traverses thegear reduction box144, theshaft148 turning a series ofplanetary gears150 within thegear reduction box144. Thegear reduction box144 and electricdrive wheel motor142 are sized to fit and positioned at least in part within the drive wheel122 (FIGS. 11-13). The planetary gear configuration of thegear reduction box144 is one means by which to increase the compactness of the gear reduction box. In the embodiment shown, thegear reduction box144 is mounted to arim123 of thedrive wheel122 by a drivewheel mounting flange152. Thestator146 of the electricdrive wheel motor142 is mounted to adrive mount tube154 by atube mounting flange156, thedrive mount tube154 being secured to thechassis112 by a plurality ofgussets158. Thus, in the illustrated embodiment, as thedrive wheel122 rotates, thegear reduction box144 coincidingly rotates with thedrive wheel122, while thestator146 remains secured against rotation with respect to thechassis112. In the embodiment shown, thedrive mount tube154 protrudes part way into thedrive wheel122 and surrounds at least a portion of thedrive wheel motor142.
• In at least some embodiments, thegear reduction box144 may additionally include an externally accessible disengaging mechanism to disengage thegear reduction box144 from the electricdrive wheel motor142 from outside thechassis112. In the embodiment shown, the disengaging mechanism includes anexternal plate159 of thegear reduction box144, having a protrudingportion160, shown also inFIG. 7A, from a side elevation perspective. When desiring to disengage thegear reduction box144, the operator may remove theexternal plate159, reverse theplate159, such that the protrudingportion160 now faces the interior of thechassis112, and reconnect theexternal plate159 to thegear reduction box144. Referring toFIG. 7A, in the present embodiment, theplate159 is removed by removing twobolts161. However, in other embodiments, a different number of bolts or a different method of securement may be employed. Referring back toFIGS. 13-14, when theexternal plate159 is reconnected in the reverse direction, the protrudingportion160 pushes in on the electricdrive motor shaft148, to disengage thegear reduction box144 from the electricdrive wheel motor142. The option to disengage thegear reduction box144 from the exterior of thechassis112 saves the operator the time and effort of having to enter the interior of thechassis112 to achieve such disengagement. Thus, should themower102 lose battery power, themower102 may readily be brought into a state where thedrive wheels122 may rotate when themower102 is pushed, even if an internal braking mechanism is engaged with respect to the electricdrive wheel motor142.
• In the present embodiment, thedrive wheel122 has an overall width of approximately 12 inches, and thegear reduction box144 and electricdrive wheel motor142 have a combined axial width of approximately 9 inches, capable of being positioned completely within the width of thedrive wheel122. In certain other embodiments, the combined axial width of the electricdrive wheel motor142 and thegear reduction box144 may vary, as may the width of thedrive wheel122. In some embodiments, the width of the electricdrive wheel motor142 may protrude beyond the width of thedrive wheel122; for example, in some embodiments, the width of the electricdrive wheel motor142 may be positioned 90 percent within the width of the drive wheel, etc. In such an embodiment, thedrive mount tube154 may be lengthened and thedrive wheel122 may be accordingly offset from thechassis112.
• In the present embodiment, the exterior mounting of thegear reduction boxes144 and the electricdrive wheel motors142 allows the battery packs126 of the present embodiment to be positioned between thedrive wheel motors142, thus lowered to an improved height relative to a ground surface as compared to the prior art, thus lowering the center of gravity of themower102. Lowering the center of gravity of themower102 increases the stability of themower102 and increases the bank angle at which themower102 may safely travel without overturning. Further, locating the electric drive wheel motors outside thechassis112 allows one or more of the battery packs126, at the lowered height, to, in some embodiments, be moved toward thefront110 of themower102 into a position underneath theoperator support116, as best shown inFIG. 7B, shortening the permissible length of themower102. Ashorter mower102 can lead to such benefits as decreased material costs during production, decreased weight, and increased compactness for greater ease of storage and maneuvering.
• In the illustrated embodiment, the fourbattery packs126 positioned closest to thefront110 of themower102 rest on afront battery floor162, while the two battery packs closest to the rear104 of themower102, rest on arear battery floor164. In other embodiments, eachbattery floor162,164 may support the same or a different number of battery packs126. In the present embodiment, therear battery floor164 is elevated about two to three inches above thefront battery floor162, which is positioned approximately six inches from the ground surface. Elevating therear battery floor164 slightly above thefront battery floor162 with respect to the ground surface provides improved clearance when themower102 is traveling up hills, over curves or drops, or over big bumps or holes where one or both of the rear wheels may drops abruptly. However, this express battery floor configuration is not required by the present disclosure. In other embodiments, the relative heights of thebattery floors162,164 may vary and more or fewer battery floors may be utilized. For instance, in certain embodiments, the rear battery floor may be lowered closer to the ground surface and angled upwards away from the ground surface in the rearward direction, or a single battery floor may be used and similarly angled upwards away from the ground surface in the rearward direction, such that the rear of a battery back positioned on such a sloped battery floor is slightly elevated above the front of the battery pack.
• When more than onebattery pack126 is utilized, the battery packs126 may be electrically interconnected to supply their power jointly. The interconnection can be either a parallel or series connection. Some embodiments may include amain battery disconnect127 that may be used to connect or disconnect the battery power from the mower. Eachbattery pack126 can include one or more removable portions situated therein, each portion including one or more battery cells (not shown). The battery packs126 can be modular, allowing them to be easily replaceable with another battery pack having an identical size and shape. Some embodiments may include battery packs126 that are readily removable. Other embodiments may include battery packs126 that are fixed in place, with less ease of removability. The battery packs126 may or may not be situated in a readily accessible location. Although, when the battery packs126 are situated in a readily accessible location, as illustrated herein, an operator can easily add multiple battery packs126 to increase operating time or power. In addition, more efficient accessibility to the battery packs126 may allow an operator to quickly swap out a dischargedbattery pack126 for a chargedbattery pack126 and resume operation without having to wait for internal batteries to charge.
• In at least some embodiments, the battery packs126 are comprised of lithium-based battery cells, capable of maintaining a near constant voltage for the duration of their state of charge. Although in other embodiments, other battery packs126 can be compromised of other types of battery cells, such as Nickel-based, Lead acid based, etc. When lithium-based, for example, the battery packs126 require no fluid refills or maintenance. The battery packs can be designed to store enough power to operate themower102 for commercial all day operations on one charge.
• Although the invention has been herein described in what is perceived to be the most practical and preferred embodiments, it is to be understood that the invention is not intended to be limited to the specific embodiments set forth above. Rather, it is recognized that modifications may be made by one of skill in the art of the invention without departing from the spirit or intent of the invention and, therefore, the invention is to be taken as including all reasonable equivalents to the subject matter of the appended claims and the description of the invention herein.

Claims (18)

What is claimed is:

1. A battery-operated mower comprising:

a first drive wheel;

a second drive wheel;

a chassis connected to the first drive wheel and the second drive wheel;

an operator support connected to the chassis for supporting an operator;

a first drive wheel motor connected to the first drive wheel;

a second drive wheel motor connected to the second drive wheel; and

a battery pack supported by the chassis and positioned at least in part between the first drive wheel motor and the second drive wheel motor.

2. The mower ofclaim 1, wherein the first drive wheel motor is positioned at least in part within the first drive wheel and the second drive wheel motor is positioned at least in part within the second drive wheel.

3. The mower ofclaim 2, wherein the first drive wheel has a first drive wheel width, the second drive wheel has a second drive wheel width, the first drive wheel motor has a first drive wheel motor width, and the second drive wheel motor has a second drive wheel motor width, and wherein the first drive wheel motor width is positioned at least 90 percent within the first drive wheel width and the second drive wheel motor width is positioned at least 90 percent within the second drive wheel width.

4. The mower ofclaim 3, wherein the battery pack comprises a first battery pack, and further comprising a second battery pack supported by the chassis and positioned at least in part underneath the operator support.

5. The mower ofclaim 4, further comprising a first planetary gear reduction box positioned at least in part within the first drive wheel and a second planetary gear reduction box positioned at least in part within the second drive wheel, the first planetary gear reduction box mechanically coupled to the first drive wheel motor and secured to the first drive wheel and the second planetary gear reduction box mechanically coupled to the second drive wheel motor and secured to the second drive wheel.

6. The mower ofclaim 5, wherein the first drive wheel comprises a first rim and the second drive wheel comprises a second rim, and wherein the first planetary gear reduction box is secured to the first rim and the second planetary gear reduction box is secured to the second rim.

7. The mower ofclaim 6, wherein the first planetary gear reduction box has a first planetary gear reduction box width and the second planetary gear reduction box has a second planetary gear reduction box width, and wherein the first planetary gear reduction box width is positioned completely within the first drive wheel width and the second planetary gear reduction box width is positioned completely within the second drive wheel width.

8. The mower ofclaim 7, wherein the first drive wheel motor is selectively engageable by a first control actuator and the second drive wheel motor is selectively engageable by a second control actuator.

9. A battery-operated mower comprising:

a chassis;

a drive wheel motor connected to an exterior portion of the chassis;

a gear mechanism mechanically coupled to the drive wheel motor;

a drive wheel connected to the gear mechanism; and

a battery pack electrically connected to the drive wheel motor and positioned at least in part within the same horizontal plane as the drive wheel motor.

10. The mower ofclaim 9, wherein the gear mechanism comprises a gear reduction box including a plurality of gears arranged in a planetary configuration.

11. The mower ofclaim 10, wherein at least a portion of the gear reduction box is positioned within the drive wheel.

12. The mower ofclaim 11, wherein the drive wheel motor is connected to the exterior portion of the chassis by a drive mount tube.

13. The mower ofclaim 12, wherein the gear reduction box further comprises a disengaging mechanism actuatable from an externally accessible face of the gear reduction box, the disengaging mechanism configured to disengage the gear reduction box from the drive wheel motor when actuated by the operator.

14. The mower ofclaim 13, wherein the drive wheel motor further comprises a shaft that axially traverses the gear reduction box, and wherein the disengagement mechanism comprises a reversible plate having a first face facing the exterior of the chassis when the gear reduction box is engaged with the drive wheel motor and a second face facing the interior of the chassis when the gear reduction box is engaged with the drive wheel motor, the first face having a protruding portion positioned such that when the plate is reversed, the protruding portion pushes on the shaft with sufficient force to disengaging the gear reduction box from the drive wheel motor.

15. A battery-operated mower comprising:

a chassis;

an operator support connected to the chassis for supporting an operator;

a first electric drive wheel motor secured to a first exterior surface of the chassis;

a first planetary gear reduction box mechanically coupled to the first electric drive wheel motor, the first planetary gear reduction box including a first system of planetary gears;

a first drive wheel secured to the first planetary gear reduction box, the first drive wheel surrounding at least a portion of the first electric drive wheel motor and at least a portion of the first planetary gear reduction box;

a second electric drive wheel motor secured to a second exterior surface of the chassis;

a second planetary gear reduction box mechanically coupled to the second electric drive wheel motor, the second planetary gear reduction box including a second system of planetary gears;

a second drive wheel secured to the second planetary gear reduction box, the second drive wheel surrounding at least a portion of the second electric drive wheel motor and at least a portion of the second planetary gear reduction box; and

a first battery pack supported by the chassis, electrically connected to the first electric drive wheel motor and the second electric drive wheel motor, the first battery pack positioned at least in part between the first electric drive wheel motor and the second electric drive wheel motor.

16. The mower ofclaim 15, further comprising a second battery pack, and wherein the chassis further includes a first battery floor supporting the first battery pack, the first battery floor positioned at a first height relative to a ground surface, and a second battery floor supporting the second battery pack, the second battery floor positioned at a second height relative to the ground surface.

17. The mower ofclaim 16, wherein the second battery pack is positioned at least in part underneath the operator support.

18. The mower ofclaim 17, wherein the first planetary gear reduction box further includes a first exterior face and a first disengaging mechanism actuatable from the first exterior face, and the second planetary gear reduction box further includes a second exterior face and a second disengaging mechanism actuatable from the second exterior face, the first disengaging mechanism configured to disengage the first planetary gear reduction box from the first electric drive wheel motor when actuated by the operator and the second disengaging mechanism configured to disengage the second planetary gear reduction box from the second electric drive wheel motor when actuated by the operator.

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