Mower blade coupling assembly

Abstract

A motor-blade assembly can include an electric motor assembly having an output shaft extending along a longitudinal axis, a coupling assembly secured to the output shaft, the coupling assembly including an elastomeric portion and a rigid portion, and a mower blade secured to the coupling assembly rigid portion by at least one retaining member. The elastomeric portion can be elastically deformable to allow the mower blade to at least partially rotate with respect to the output shaft about at least two different axes.

Description

MOWER BLADE COUPLING ASSEMBLYRELATED APPLICATIONS

[0001] This application claims priority to United States Provisional Patent Application Serial Number 63 / 517,543, filed on August 3, 2023; claims priority to United States Provisional Patent Application Serial Number 63 / 517,546, filed on August 3, 2023; and claims priority to United States Provisional Patent Application Serial Number 63 / 551,200, filed on February 8, 2024, the entireties of each of which are hereby incorporated herein by reference.TECHNICAL FIELD

[0002] The present invention generally relates to coupling assembly for use in mounting a mower blade to a shaft, more particularly to a shaft of an electrical motor.BACKGROUND

[0003] The use of electric motors in mower applications has become increasingly common. In some applications, a rotary cutting blade of the mower is directly coupled to the shaft of the electric motor. During operation, it is sometimes the case that the cutting blade will strike an object, such as a rock, that will cause the blade to either deflect or stop rotating altogether. In either case, damage to the motor shaft can result. Improvements are desired.SUMMARY

[0004] A motor-blade assembly can include an electric motor assembly having an output shaft extending along a longitudinal axis; a coupling assembly secured to the output shaft, the coupling assembly including an elastomeric portion and a rigid portion; and a mower blade secured to the coupling assembly rigid portion by at least one retaining member; wherein the elastomeric portion is elastically deformable to allow the mower blade to at least partially rotate with respect to the output shaft about at least two different axes.

[0005] In some examples, the elastomeric portion is received into an opening defined by the rigid portion.

[0006] In some examples, the rigid portion includes a recessed portion for receiving the mower blade.

[0007] In some examples, the at least one retaining member includes a head portion abutting the mower blade and a threaded portion received by the output shaft.

[0008] In some examples, the at least one retaining member includes a concaveshaped portion for receiving a portion of the mower blade when a length of the mower blade is disposed at an oblique angle to the longitudinal axis.

[0009] In some examples, the elastomeric portion and the rigid portion are separate components coupled together with an interference fit resulting in a static friction force preventing relative rotation between the elastomeric portion and the rigid portion below a relative torque force below the static friction force.

[0010] In some examples, the motor-blade assembly can further include: a first coupling part coupled to the output shaft; a second coupling part defining the elastomeric portion and being coupled to the first coupling part; and a third coupling part defining the rigid portion and being coupled to the second coupling part.

[0011] In some examples, the second and third coupling parts are coupled together with an interference fit resulting in a static friction force preventing relative rotation between the second and third coupling parts below a relative torque force below the static friction force.

[0012] In some examples, a portion of the first coupling part defines a protrusion received into a complementarily shaped recess of the second coupling part.

[0013] In some examples, the protrusion and recess have a non-circular shape.

[0014] In some examples, the first coupling part and the second coupling part define a hub member, with the elastomeric portion defined by the second coupling part at least partially surrounding the first coupling part.

[0015] In some examples, the first and second coupling parts are formed from a different material.

[0016] In some examples, the coupling assembly is coupled to the output shaft by an output shaft retaining member.

[0017] In some examples, the third coupling part is secured to the mower blade by a pair of retaining members.

[0018] In some examples, the third coupling part includes a radially inwardly extending lip to provide an abutment surface between the second coupling part and the third coupling part.

[0019] In some examples, the elastomeric portion and the rigid portion are separate components coupled together such that a first surface of the elastomeric portion contactsa second surface of the rigid portion, wherein relative movement between the first and second surfaces is prevented below a minimum torque force and allowed above the minimum torque force.

[0020] In some examples, the minimum torque force equal to or equal to a maximum torque rating of the electrical motor.

[0021] In some examples, the maximum torque rating is at least 22 ft-lb.

[0022] A coupling assembly for securing a mower blade to a motor shaft can include an elastomeric portion extending along a longitudinal axis; and a rigid portion defining a central opening within which the elastomeric portion is received, the rigid portion defining a mounting surface for securing the mower blade; wherein the elastomeric portion is elastically deformable to allow the mower blade to at least partially rotate with respect to the output shaft about at least two different axes.

[0023] In some examples, the elastomeric portion defines a sidewall having a noncircular shape.

[0024] In some examples, the rigid portion defines a recess exposing a bottom surface of the elastomeric portion such that at least a portion of the bottom surface is contactable with the mower blade, when installed.

[0025] In some examples, the coupling assembly further includes a threaded retaining member for clamping the mower blade against a portion of the elastomeric portion bottom surface.

[0026] In some examples, the retaining member includes a concave-shaped portion for receiving a portion of the mower blade when a length of the mower blade is disposed at an oblique angle to the longitudinal axis.

[0027] In some examples, the elastomeric portion is defined by a hub member configured to be coupled to the motor shaft.

[0028] In some examples, the rigid portion is defined by a periphery member configured to be coupled to the mower blade.

[0029] In some examples, the rigid portion includes a radially inwardly extending lip to provide an abutment surface between the elastomeric portion and the rigid portion.

[0030] In some examples, the elastomeric and rigid portions are coupled together such that relative movement between contacting surfaces of the elastomeric and rigid portions is prevented below a minimum torque force and allowed above the minimum torque force.

[0031] A coupling assembly for securing a mower blade to a motor shaft can include a first coupling part extending along a longitudinal axis, the first coupling part defining a central aperture extending along the longitudinal axis and being for receiving the motor shaft; a second coupling part coupled with the first coupling part, the second coupling part being formed from an elastomeric material; and a third coupling part defining an interface portion for rotationally engaging with the mower blade, the third coupling part being coupled with the second coupling part with an interference fit resulting in a static friction force preventing relative rotation between the second and third coupling parts below a relative torque force below the static friction force.

[0032] In some examples, the second coupling part is received into a central opening defined in the third coupling part.

[0033] In some examples, the third coupling part includes a recessed portion for receiving the mower blade.

[0034] In some examples, a portion of the first coupling part defines a protrusion received into a complementarily shaped recess of the second coupling part.

[0035] In some examples, the protrusion and recess have a non-circular shape.

[0036] In some examples, the first coupling part and the second coupling part cooperate to define a hub member, with the second coupling part at least partially surrounding the first coupling part.

[0037] In some examples, the third coupling part includes a radially inwardly extending lip to provide an abutment surface between the second coupling part and the third coupling part.

[0038] A coupling assembly for securing a mower blade to a motor shaft can include a first part including an elastomeric portion extending along a longitudinal axis and defining a central aperture for receiving the motor shaft; and a second part including a rigid portion defining a central opening within which the elastomeric portion is received such that a mechanical interference exists between the first and second parts in a direction of rotation of the coupling assembly, wherein the mower blade is mounted to the rigid portion; wherein the elastomeric portion is elastically deformable to allow the mower blade to at least partially rotate with respect to the output shaft about at least two different axes.

[0039] In some examples, the elastomeric portion defines a sidewall having a noncircular shape.

[0040] In some examples, the first part contacts the second part at least along an outer perimeter of the first part.

[0041] In some examples, the central opening of the rigid portion exposes a bottom surface of the elastomeric portion such that at least a portion of the bottom surface is contactable with the mower blade, when installed.

[0042] In some examples, the bottom surface of the elastomeric portion includes at least one annular ring extending in an axial direction.

[0043] In some examples, the bottom surface of the elastomeric portion includes a pair of annular rings spaced apart by a recessed portion.

[0044] In some examples, the first part includes an integrally formed key for engaging with a corresponding slot in the motor shaft.

[0045] In some examples, the coupling assembly further includes a pair of threaded retaining members for securing the mower blade to the rigid portion and against a portion of the elastomeric portion bottom surface.

[0046] In some examples, the coupling assembly further includes an output shaft retaining member for secunng the first part to the motor shaft.

[0047] A coupling assembly for securing a mower blade to a motor shaft can include: a first coupling part extending along a longitudinal axis, the first coupling part defining a central aperture extending along the longitudinal axis and configured to receive the motor shaft; a second coupling part coupled with the first coupling part, the second coupling part being formed from an elastomeric material; and a third coupling part defining an interface portion for rotationally engaging with the mower blade, the third coupling part being coupled with the second coupling part such that relative movement between contacting surfaces of the second and third coupling parts is prevented below a minimum torque force and allowed above the minimum torque force.

[0048] In some examples, a top surface of the second coupling part has at least one angled or chamfered surface for increasing clearance between the coupling assembly and the motor assembly.

[0049] In some examples, the second coupling part innermost diameter is defined by an inwardly extending lip that contacts an end surface of the second coupling part

[0050] In some examples, the coupling assembly further includes a support plate contacting an end surface of the second coupling part and an end surface of the third coupling part.

[0051] A variety of additional inventive aspects will be set forth in the description that follows. The inventive aspects can relate to individual features and to combinations of features. It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the embodiments disclosed herein are based.BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings, which are incorporated in and constitute a part of the description, illustrate several aspects of the present disclosure. A brief description of the drawings is as follows below.

[0053] Figure 1 is a first perspective view depicting a motor-blade assembly having features in accordance with the present disclosure.

[0054] Figure 2 is a second perspective view of the motor-blade assembly show n in Figure 1.

[0055] Figure 3 is a first side elevation view of the motor-blade assembly shown in Figure 1.

[0056] Figure 3 A is a first side elevation view of the motor-blade assembly shown inFigure 1, w ith the blade shown in a deflected state.

[0057] Figure 4 is a bottom plan view of the motor-blade assembly shown in Figure 1.

[0058] Figure 5 is a second side elevation view of the motor-blade assembly shown in Figure 1.

[0059] Figure 6 is a partial cross-sectional side view- of the motor-blade assembly shown in Figure 1.

[0060] Figure 7 is an exploded perspective view- of the motor-blade assembly shown in Figure 1.

[0061] Figure 8 is an exploded perspective view of a coupling assembly of the motorblade assembly shown in Figure 1.

[0062] Figure 8A is a partially exploded perspective view of the coupling assembly of the motor-blade assembly shown in Figure 1 .

[0063] Figure 9 is a first perspective view of a first coupling part of the coupling assembly shown in Figure 8.

[0064] Figure 10 is a second perspective view of the first coupling part shown in Figure 9.

[0065] Figure 11 is a top plan view of the first coupling part shown in Figure 9.

[0066] Figure 12 is a bottom plan view of the first coupling part shown in Figure 9.

[0067] Figure 13 is a side elevation view of the first coupling part shown in Figure9.

[0068] Figure 14 is a first perspective view of a second coupling part of the coupling assembly shown in Figure 8.

[0069] Figure 15 is a second perspective view of the second coupling part shown in Figure 14.

[0070] Figure 16 is a top plan view of the second coupling part shown in Figure 14.

[0071] Figure 17 is a bottom plan view of the second coupling part shown in Figure14.

[0072] Figure 18 is a cross-sectional side view of the second coupling part shown inFigure 14.

[0073] Figure 19 is a first perspective view of a third coupling part of the coupling assembly shown in Figure 8.

[0074] Figure 20 is a second perspective view of the third coupling part shown in Figure 19.

[0075] Figure 21 is a top plan view of the third coupling part shown in Figure 19.

[0076] Figure 22 is a bottom plan view of the third coupling part shown in Figure 19.

[0077] Figure 23 is a first side elevation view of the third coupling part shown inFigure 19.

[0078] Figure 24 is a second side elevation view of the third coupling part shown in Figure 19.

[0079] Figure 25 is a perspective view of a retaining member of the motor-blade assembly shown in Figure 1.

[0080] Figure 26 is a second perspective view of the retaining member shown in Figure 25.

[0081] Figure 27 is a side elevation view of the retaining member shown in Figure 25.

[0082] Figure 28 is a first perspective view depicting a second example of a motorblade assembly having features in accordance with the present disclosure.

[0083] Figure 29 is a second perspective view of the motor-blade assembly shown inFigure 28.

[0084] Figure 30 is a first perspective view depicting a coupling assembly of the motor-blade assembly shown in Figure 28.

[0085] Figure 31 is a second perspective view of the coupling assembly shown in Figure 30.

[0086] Figure 32 is a partial cross-sectional side view of the motor-blade assembly- shown in Figure 28.

[0087] Figure 33 is a first perspective view depicting a third example of a motorblade assembly having features in accordance with the present disclosure.

[0088] Figure 34 is a second perspective view of the motor-blade assembly shown inFigure 33.

[0089] Figure 35 is a first side elevation view of the motor-blade assembly shown in Figure 33.

[0090] Figure 36 is a first side elevation view of the motor-blade assembly show n in Figure 33, with the blade shown in a deflected state.

[0091] Figure 37 is a bottom plan view of the motor-blade assembly shown in Figure 33.

[0092] Figure 38 is a second side elevation view of the motor-blade assembly shown in Figure 33.

[0093] Figure 39 is a partial cross-sectional side view of the motor-blade assembly shown in Figure 33.

[0094] Figure 39 A is a cross-sectional view of a modified version of the motor-blade assembly shown in Figure 39.

[0095] Figure 40 is an exploded perspective view of the motor-blade assembly shown in Figure 33.

[0096] Figure 41 is a first partial exploded perspective view- of the motor-blade assembly shown in Figure 33.

[0097] Figure 42 is a second partial exploded perspective view- of the motor-blade assembly shown in Figure 33.

[0098] Figure 43 is a first perspective view of a first coupling part of the motor-blade assembly shown in Figure 33.

[0099] Figure 44 is a second perspective view of the first coupling part shown in Figure 43.

[0100] Figure 45 is a top plan view of the first coupling part shown in Figure 43.

[0101] Figure 46 is a bottom plan view of the first coupling part shown in Figure 43.

[0102] Figure 47 is a cross-sectional perspective view of the first coupling part shown in Figure 43.

[0103] Figure 48 is a first perspective view of a second coupling part of the motorblade assembly shown in Figure 33.

[0104] Figure 49 is a second perspective view of the second coupling part shown in Figure 48.

[0105] Figure 50 is a top plan view of the second coupling part shown in Figure 48.

[0106] Figure 51 is a bottom plan view of the second coupling part shown in Figure48.

[0107] Figure 52 is a cross-sectional perspective view of the second coupling part shown in Figure 48.

[0108] Figure 53 is a first perspective view' depicting a fourth example of a motorblade assembly, including a coupling assembly and a mower blade, having features in accordance with the present disclosure.

[0109] Figure 54 is a second perspective view of the motor-blade assembly shown in Figure 53.

[0110] Figure 55 is a first side view of the motor-blade assembly shown in Figure 53.

[0111] Figure 56 is a second side view of the motor-blade assembly shown in Figure 53.

[0112] Figure 57 is a bottom view' of the motor-blade assembly shown in Figure 53.

[0113] Figure 58 is a first cross-sectional side view' of the motor-blade assembly shown in Figure 53.

[0114] Figure 58 A is a partial cross-sectional side view of the motor-blade assembly shown in Figure 53, with a support plate added between the mower blade and the coupling assembly.

[0115] Figure 59 is a second cross-sectional side view' of the motor-assembly shown in Figure 53.

[0116] Figure 60 is a perspective exploded is a first cross-sectional side view of the motor-blade assembly shown in Figure 53.

[0117] Figure 61 is a first perspective view of a first coupling part of the coupling assembly shown in Figure 53.

[0118] Figure 62 is a second perspective view of the first coupling part shown in Figure 61.

[0119] Figure 63 is a top view of the first coupling part shown in Figure 61.

[0120] Figure 64 is a bottom view of the first coupling part shown in Figure 61.

[0121] Figure 65 is a cross-sectional side view- of the first coupling part shown inFigure 61.

[0122] Figure 66 is a first perspective view' of a second coupling part of the coupling assembly shown in Figure 53.

[0123] Figure 67 is a second perspective view of the second coupling part shown in Figure 61.

[0124] Figure 68 is a top view of the second coupling part shown in Figure 61.

[0125] Figure 69 is a bottom view of the second coupling part shown in Figure 61.

[0126] Figure 70 is a cross-sectional side view of the second coupling part shown in Figure 61.

[0127] Figure 71 is a perspective view' of the first coupling part of the coupling assembly shown in Figure 53.

[0128] Figure 72 is a top view of the first coupling part of the first coupling part shown in Figure 71.

[0129] Figure 73 is a top cross-sectional view showing the first, second, and third coupling parts of the coupling assembly shown in Figure 53.

[0130] Figure 74 is a perspective view of a mower for which the motor-blade assemblies shown in Figures 1, 28, 33, and 53 can be utilized.

[0131] Figure 75 is a perspective bottom view' of the mower shown in Figure 71 .DETAILED DESCRIPTION

[0132] Reference will now be made in detail to exemplary aspects of the present disclosure that are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0133] Referring to Figures 1-27, 28-32, and 33-40, a motor-blade assembly 10, 10’, and 10” is presented. As shown, the motor-blade assembly 10, 10’. and 10” includes an electric motor assembly 20 and a mower blade 30 secured to the electric motor assembly 20 via a coupling assembly 100.

[0134] As further depicted at Figures 74 and 75, a plurality of the motor-blade assemblies 10, 10’, 10”. and 10’” may be used with a mower 1. In the example shown, three motor-blade assemblies 10, 10’, and 10” are mounted to a deck 2 of the mowersuch that a portion of the electric motor assemblies 20 extends through a bottom side of the deck 2 and such that the coupling assemblies 100 and blades 30 are housed within an interior area defined by the deck 2. Other numbers of motor-blade assemblies 10, 10’, and 10” may be used.Motor-Blade Assembly 10

[0135] Referring to Figures 1-27. a first example of a motor-blade assembly 10 is presented. In one aspect, the electric motor assemblies 20 assembly includes a motor housing 22 within which a stator and rotor (not shown) are disposed. The electric motor assembly 20 also includes an electric motor shaft 24 operably coupled to the rotor, which can be provided with a recess 24a for receiving a key. The electric motor assembly 20 is further shown as including a power cable 26 for powering the stator. The pow er cable 26 is shown with a connector assembly 26a for engagement with a power source and optionally a motor controller (not shown).

[0136] As referenced at Figure 7, the mower blade 30 extends between a first side 30a and a second side 30b and between a first end 30c and a second end 30d. Proximate the first end 30c, the mower blade 30 is provided with a cutting edge 30e on the second side 30b and a deflector portion 30g on the first side 30a. Similarly, proximate the second end 30d, the mower blade 30 is provided with a cutting edge 30f on the first side 30a and a deflector portion 30h on the second side 30b. The mower blade 30 is further shown as including a central opening 30i defined by a sidewall 30j extending between atop surface 30k and a bottom surface 30m of the mow er blade 30.

[0137] With additional reference to Figures 6, 8, and 8A, the coupling assembly 100 can include a first coupling part 102 that is received into a second coupling part 104, and a third coupling part 106 receiving the second coupling part 104.

[0138] As most easily viewed at Figures 9-13, the first coupling part 102 includes a main body 102a defining a central aperture 102b for receiving the electric motor shaft 24. In one aspect, a key 102p is integrally formed in the main body 102a and is received into the motor shaft recess 24a. In some examples, the first coupling part 102 is slip fit onto the electric motor shaft 24. In other examples, the first coupling part 102 is alternatively or additionally secured to the electric motor shaft 24 with a retaining member such as a pin, threaded screw, or bolt. The first coupling part 102 is further shown as including top portion 102c defining atop surface 102d and a side surface 102e. In the example shown, side surface 102e is shown as being a cylindrical surface. Othershapes are possible. The first coupling part 102 is further shown as including a flange portion 102f defining a top surface 102g, side surface 102h, and bottom surface 102i. In the example shown, side surface 102h is shown as being a cylindrical surface. The first coupling part 102 is further shown as including a protrusion 102j, having an outer perimeter 102k defining a plurality of side surfaces 102m, and a bottom surface 102n. In the example shown, the side surfaces 102m are flat or planar side surfaces, but may be provided in other arrangements, as described below.

[0139] The first coupling part 102 may be formed from a variety of materials, for example metal materials, polymeric materials, and / or composite materials. In one example, the first coupling part is formed from a steel material as either a powdered metal, casting, and / or a machined part. In one aspect, the first coupling part is configured as a relatively rigid structure capable of transmitting torque from the electric motor shaft 24 to the second coupling part 104 without significant flexing or bending. Accordingly, the first coupling part 102 may be referred to as forming a rigid portion of the coupling assembly 100.

[0140] As most easily viewed at Figures 14-18, the second coupling part 104 includes a main body 104a defining a central aperture 104b extending along a sidewall 104c, a top surface 104d, a side surface 104e, and a bottom surface 104f. In the example show n, side surface 104e is shown as being a cylindrical surface. Other shapes are possible. The main body 104a is further shown as defining a recessed portion 104g having a side surface 104h defining a plurality of side surfaces 104i extending to a bottom surface 104j . In the example shown, the side surfaces 104i are flat or planar side surfaces, but may be provided in other arrangements, as described below. In one aspect, it is noted that the top surface 104d is sloped downward in a radial inward direction (i. e. , in a direction toward a longitudinal or rotational axis X) to accommodate the difference between the thickness of the first coupling part flange portion 102f and that of an inward extending lip 106p of the third coupling part 106 discussed below. As can be most easily viewed at Figure 6, this configuration results in the surfaces 102g and 104d being generally coplanar.

[0141] In one aspect, the recessed portion 104g has a negative shape that is complementary to the positive shape defined by the protrusion 102j of the first coupling part 102 such that the protrusion 102j can be received into the recessed portion 104g until the surfaces 102n, 104j abut and / or the surfaces 102i, 104d abut. Once received, the side surfaces 102m and 104i engage, due to mechanical interference between the surfaces, such that rotation of the first coupling part 102 caused by the electric motor shaft 24 willtransfer torque to the second coupling part 104. Such a connection involving mechanical interference may be referred to as a fixed or rigid coupling and / or a rotationally fixed coupling. In the example shown, six side surfaces 102m, 104i are provided in a hexagonal shape. However, other numbers of side surfaces and polygonal shapes may be used without departing from the concepts presented herein. For example, the side surfaces 102m, 104i can include three sides defining a triangular shape, four sides defining a rectangular or square shape, five sides defining a pentagonal shape, eight sides defining an octagonal shape, etc. Non-convex polygonal shapes, such as star shapes, may also be defined by the side surfaces 102m, 104i. Other shapes are also possible, such as noncircular shapes, oval shapes, elliptical shapes, and obround shapes. Generally polygonal shapes that would otherwise be considered as being polygon but for having rounded comers may also be used. Further, the side surfaces 102m, 104i can be formed as flat or curved sides to define any shape having no order of rotational symmetry as such a shape would inherently prevent relative rotation between the first and second coupling parts 102, 104. Due to rotational and balance concerns, a shape that is arranged to have a center or centroid aligned with the longitudinal axis X of the electric motor shaft 24, the first coupling part 102 and second coupling part 104 is preferred. In one aspect, the first and second coupling parts 102, 104 may also be referred to as portions of a hub member 105, as illustrated at Figure 8 A.

[0142] The second coupling part 104 may be formed from a variety of materials. In some examples, the second coupling part is formed from an elastomeric or polymeric material such as plastic, natural or synthetic rubbers (e.g., ethylene propylene diene monomer rubber or EPDM rubber), and / or combinations thereof. In one example, the second coupling part 104 is formed from a natural rubber a Shore A hardness durometer of about 50 to 70. In one aspect, the second coupling part 104 is configured as a structure sufficiently rigid to transmit torque from the first coupling part to the third coupling part while being flexible enough to elastically deform, deforming beyond a torque or torsional shear value. In one example, the side surface 104e or outer perimeter of the second coupling part 104 can elastically deform up to about 50 foot-pounds of torque while the center of the second coupling part 104 is held in a stationary position. Accordingly, the second coupling part 104 may be referred to as forming an elastomeric portion of the coupling assembly 100.

[0143] In the example shown, the perimeter dimensions of the recessed portion 104g of the second coupling part 104 are slightly less than that of the corresponding perimeterdimensions of the protrusion 102j of the first coupling part such that the first coupling part 102 can be received by the second coupling part in an interference fit (e.g., press fit or friction fit) type arrangement. Alternative or additional securing means may be utilized, for example, mechanical fasteners and / or adhesives. It is noted that the protrusion and recess configuration of the first and second coupling parts 102, 104 could be reversed such that the first coupling part 102 defines a recess for receiving a protrusion of the second coupling part 104.

[0144] As most easily viewed at Figures 14-18, the third coupling part 106 is provided with a main body 106a defining a central aperture 106b extending along a sidewall 106c, a top surface 106d, a side surface 106e, and a bottom surface 106f. As shown, the sidewall 106c and side surface 106e are shown as being cylindrical surfaces. Other shapes are possible. The third coupling part 106 is further shown as including a recessed portion 106g for receiving the mower blade 30. The recessed portion 106g may more broadly be referred to as an interface portion or mounting surface. In one aspect, the recessed portion 106g extends through the top surface 106d and side surface 106e to define first and second bottom surfaces 106h. 106i. first and second side surfaces 106j. 106k, and third and fourth side surfaces 106m, 106n. The third coupling part 106 is also shown as including a radially inwardly extending lip 106p, formed as an extension of the top surface 104d. The lip 106p provides for an abutment surface between the second and third coupling parts 104. 106.

[0145] The third coupling part 106 may be formed from a variety of materials, for example metal materials, plastic or polymeric materials, and / or composite materials. In one example, the third coupling part is formed from a steel material as either a powdered metal, casting, and / or a machined part. In one aspect, the third coupling part 106 is configured as a relatively rigid structure capable of transmitting torque from the first and second coupling parts 102, 104 to the mower blade 30 without significant flexing or bending. Accordingly, the third coupling part 106 may be referred to as forming a rigid portion of the coupling assembly 100. In one aspect, the diameter of the sidewall 106c of the third coupling part 106 is slightly less than that of the diameter of the side surface 104e such that the second coupling part 104 can be received by the third coupling part 106 with an interference fit (e.g., press fit or friction fit) manner until the inward extending lip 106p of the third coupling part 106 abuts the top surfaces 104d of the second coupling part 104. Such a connection allows for the third coupling part 106 to rotate relative to the second coupling part 104 when a torque or torsional shear stress exceedsthe static friction force between the side surface 104e and sidewall 106c. In some characterizations, the interface between the side surface 104e and sidewall 106c may be referred to as a slip plane.

[0146] Referring to Figures 25-27, a retaining member 110 is shown in further detail. The retaining member 110 secures the mower blade 30 and coupling assembly 100 to the electric motor shaft 24 of the electric motor assembly 20 such that a surface 110g of the retaining member 110 exerts a clamping force onto the mower blade 30. As shown, the retaining member 110 is formed from a main body 110a which further defines a threaded portion 110b, a head portion 110c, a flange portion 11 Od defining a flange face 11 Oe, and a blade control portion 11 Of. In one aspect, the threaded portion 110b is configured to be received by a correspondingly shaped threaded opening 24b in the electric motor shaft 24 of the electric motor assembly 20. In one aspect, the head portion 110c is configured as a standard hex head such that a wrench or other tool can be used to tighten the retaining member 110. The head portion 110c can be configured with other tool interface shapes, such as a recess with a hex shape for an Allen tool or bit. In one aspect, the blade control portion 11 Of is located between the threaded portion 110b and the flange face 1 lOd, and thus can also be characterized as being located between the threaded portion 110b and the head portion 110c. As show n, the blade control portion 11 Of is provided with a first cylindrical outer surface 11 Oh, a second outer cylindrical outer surface 11 Oi, a first sloped surface HOj, a second sloped surface 110k, and a central portion 110m. The central portion 1 10m is provided with a smaller diameter in comparison to the surfaces 1 l Oh, HOi and is located between the sloped surfaces HOj, 110k. Accordingly, the sloped surfaces 1 lOh, 1 lOi slope in a narrowing direction from the surfaces 1 lOh, 1 lOi towards the central portion 110m to form a generally concave shape defining a recessed portion 1 lOn. In one aspect, the recessed portion HOn can be characterized as a concave recess or cavity, a radial recess or cavity, and / or a radially inward directed recess or cavity. Although surfaces HOj, 110k, and 110m are shown as being straight surfaces, the recessed portion 1 lOn can be defined by a continuously curved surface as well.

[0147] Referring to back to Figure 6, a vertical cross-section of the motor-blade assembly 10 is presented such that the interconnections between the electric motor shaft 24, coupling assembly 100, retaining member 110, and mower blade 30 are shown in further detail. As noted above, the coupling assembly 100 is assembled such that surface 102h contacts or abuts surface 104d; surface 104d contacts or abuts the underside of lip 106p; surfaces 104e, 104c contact or abut each other; and surfaces 102m, 104i contact orabut each other, such that surfaces 102n, 104j abut or contact each other. The coupling assembly 100 is installed onto the electric motor shaft 24 such that the surface defining central opening 102b surrounds and contacts the electric motor shaft 24 in a slip fit type manner using an interacting key and key way to transmit torque. The mower blade 30 is installed onto the coupling assembly 100 such that the mower blade 30 is received into the recessed portion 106g of the third coupling part 106 and such that the top surface 30k of the mower blade 30 contacts and abuts surface 104f of the second coupling part 104. In this position, the first side 30a of the mower blade 30 contacts and abuts the side surfaces 106j, 106k while the second side 30b of the mower blade 30 contacts and abuts the side surfaces 106m, 106n. By virtue of this contact, the rotation of the third coupling part 106 imparts torque and rotation onto the mower blade 30. Once the mower blade 30 is received by the recessed portion 106g, the retaining member 110 can be inserted through the central apertures of the first, second, and third coupling parts 102, 104, 106 and threaded into the recess 24a of the electric motor shaft 24. When the retaining member 110 is fully threaded and torqued, mower blade 30 is clamped between the flange face I lOe of the retaining member 110 and the surface 104f of the second coupling member 104 to secure the mower blade 30 within the recessed portion 106g. In this position, the surface HOi of the retaining member 110 is received by and abuts the sidewall 30j of the mower blade while the surface 1 lOh of the retaining member 110 is received by and abuts the sidewall 104c of the second coupling part 104. As a result, the cavity portion 11 On of the blade control portion 1 1 Of is open and unobstructed when the mower blade 30 is in the secured and aligned position shown at Figure 6.

[0148] With the above-described configuration, the coupling assembly 100 is advantageously able to protect the electric motor assemblies 20 and electric motor shaft 24 from impact loads caused by the mower blade 30 striking an object such as a rock, stump, or branches / limbs in multiple ways. In one scenario, when the rotating mower blade 30 strikes an object, the resulting impact torque or torque shear will momentarily rise to a level sufficient to elastically deform the second coupling part 104 in a rotational direction about a rotational axis. These same forces may be also sufficient to overcome the static friction force at the slip plane defined at surfaces 104e, 106c such that relative rotation between the second and third coupling parts 104, 106 occurs. By allowing for elastomeric deformation and controlled slippage, the resulting angular impulse or impact torque imparted onto the electric motor shaft 24 by the impact event can be significantly reduced well ahead of any safety shut-down controls being enacted that would eventuallycut power off to the electric motor assembly 20. Although the combined energy absorption or dampening effect of these features provides certain advantages, each of these features alone is advantageous in reducing the angular impulse or impact torque imparted onto the electric motor shaft 24, at least to some degree. In addition to the above dynamic, some types of impact events can also cause the leading edge of the mower blade 30 to deflect upward, and potentially over the impacted object, for example as illustrated at Figure 3A. An impact force on the mower blade 30 of this type can impart a significant bending moment force onto the electric motor shaft 24. However, with the disclosed design, these forces can be mitigated by the elastic properties of the second coupling part 104 and the blade control portion 11 Of of the retaining member 110. As the mower blade 30 is compressed between the retaining member flange portion 1 lOd and the elastomeric second coupling part 104, the mower blade 30 can vertically deflect at one end to a certain degree (i.e., such that the length of the blade is at an oblique angle to the longitudinal axis X) as the second coupling part 104 will elastically compress to accommodate such movement. As shown, the blade 30 is enabled to rotate to at least some degree by the second coupling part 104, generally about an axis Y, orthogonal to the axis X, and through an angle al. In the example shown, the angle al is about 5 degrees and may be referred to as the vertical angular displacement of the blade. Further, the blade control portion 11 Of is shaped to allow the top edge of the sidewall 30j, proximate top surface 30k and on the upwardly deflecting end of the mower blade 30, to be received into the cavity portion 1 1 On as the second coupling part 104 compresses. Accordingly, the impact bending or moment force onto the retaining member 110 and thus the electric motor shaft 24, can be significantly reduced during an impact event by the disclosed design. This arrangement can also operate to protect the mower blade 30 from further damage as well. In view of the above, it can be appreciated that the above-described features enable the coupling assembly 100 to allo ? the blade 30 to rotate with respect to the motor shaft about two different axes (e.g., X-axis and Y-axis) to simultaneously minimize and absorb the torsional impact force imparted onto the motor shaft.Motor-Blade Assembly 10’

[0149] Referring to Figures 33-40, a second example of a motor-blade assembly 10’ is presented. Motor-blade assembly 10' includes the same electric motor assemblies 20 and mower blade 30 as shown and described for motor-blade assembly 10’ and can be used in conjunction with a mower 1 and deck 2, as illustrated at Figures 74 and 75, in thesame manner as described above. Accordingly, the above-provided description for these features is fully applicable for motor-blade assembly 10' and need not be repeated again in this section. Motor-blade assembly 10’ is similar to motor-blade assembly 10 in that motor-blade assembly 10’ includes a coupling assembly 100 comprising first and second coupling parts 102, 104 forming a hub member 105, and a third coupling part 106 in which a slip plane is defined between the second and third coupling parts 104. 106. However, motor blade assembly 10’ differs in that the mower blade 30 is mounted directly to the third coupling part 106 via retaining members or fasteners I l la, 11 1b with the first coupling part 102 being mounted to the shaft 24 via retaining member 110. With such a configuration, the first and second coupling parts 102, 104 can be joined together by a variety of means such as by a friction or interference fit, a mechanical interface, fasteners, adhesives, and over-molding, and may also be collectively referred to as hub member 105. As shown, the first coupling part 102 defines a central through hole 102b for receipt of the electric motor shaft 24, wherein the retaining member 110 abuts the bottom surface of the first coupling part 102. By fastening the second coupling part 102 directly to the shaft 24 in this manner, the retaining member 110 can advantageously be provided with a shorter cantilevered length in contrast to the previous embodiment. As shown, the third coupling part 106 includes a pair of threaded openings 106s, which may be referred to collectively as an interface portion 106s. that align with a corresponding pair of through holes 30p provided in the mower blade 30 such that fasteners I l la. 111b can be used to secure the mower blade 30 to the third coupling part 106, as illustrated at Figure 32. Opening 30i in the mow er blade 30 for this embodiment is also shown as being enlarged relative to the first embodiment such that the fastener 110 can be accessed with the blade 30 mounted to the third coupling part 106.

[0150] In one aspect, the first coupling part 102 can also be provided with a radially extending flange portion 102q extending within the material of the second coupling part 104. Once the coupling assembly 100 is assembled, and with reference to Figure 32, the second coupling part 104 is placed in a compressive state between the blade 30 and the third coupling part, via the radially inwardly extending lip 106p, wherein the material of the second coupling part 104 is also compressed against the flange portion 102q of the first coupling part 102. In cases where the second coupling part 104 is overmolded onto the first coupling part 102, this state of compression of the second coupling part 104 increases the bond joint between the first and second coupling parts 102, 104. Accordingly, this configuration results in a more robust assembly with increasedresistance to potential failure of the bond joint due to shear forces generated during an impact event.Motor-Blade Assembly 10”

[0151] Referring to Figures 33-52, a third example of a motor-blade assembly 10” is presented. Motor-blade assembly 10” includes the same electric motor assemblies 20 and mower blade 30 as shown and described for motor-blade assemblies 10 and 10’ and can be used in conjunction with a mower 1 and deck 2, as illustrated at Figures 74 and 75, in the same manner as described above. Accordingly, the above-provided description for these features is fully applicable for motor-blade assembly 10” and need not be repeated again in this section. Motor-blade assembly 10” is similar to motor-blade assembly 10’ in that motor-blade assembly 10” includes a coupling assembly 100 comprising a first coupling part 102, a second coupling part 104, and a third coupling part 106 in which the first coupling part 102 is mounted to the shaft 24 via retaining member 110 and in which the mower blade 30 is mounted to the third coupling part 106 via retaining members I l la. 1 11b.

[0152] In embodiments, the hub member 105 can be received within a central opening 106b of a third coupling part 106, alternatively referred to as a periphery member 107, with the first coupling part 102 defining a central aperture 102b for receipt of the electric motor shaft 24 of the electric motor assembly 20, and the periphery member 107 defining an interface portion 106s configured to be coupled to the mower blade 30. Motor-blade assembly 10” differs from the other disclosed embodiments in that the elastomeric portion of the hub member 105 can define an outer sidewall having a noncircular shape, for example in the form of a polygon or other shape having a number of flat surfaces intersecting at comers which can be elastically deformable to allow the mower blade to at least partially rotate with respect to the output shaft about at least two different axes.

[0153] As depicted in Figures 41-42, the coupling assembly 100 can include a first coupling part 102 at least partially surrounded by a second coupling part 104. which in some embodiments can be formed as a multi-material, unitary member, collectively referred to as a hub member 105. In embodiments, the first coupling part 102 can be formed of a rigid material, while the second coupling part 104 can be formed of an elastic material. In the example shown, the first coupling part 102 is provided with a polygonal- type shape which enhances the connection between the first and second coupling parts102, 104 and provides for other advantages explained below. The second coupling 104 part can represent the elastomeric portion of the coupling assembly 100. The coupling assembly 100 also includes a third coupling part 106, alternatively referred to as a periphery member 107, defining a recess into which the hub member 105 can be positioned. As further depicted, the coupling assembly 100 can also include a first retaining member 110 configured to couple the first coupling part 102 to the electric motor shaft 24, and one or more second retaining members I l la, 111b configured to couple the mower blade 30 to the periphery member 107.

[0154] As depicted in Figure 43-47, the first coupling part 102 includes a main body 102a defining a central aperture 102b for receiving the electric motor shaft 24. In one aspect, a key is integrally formed in the main body 102a and is received into the motor shaft recess 24a. The main body 102a further defines a top surface 102g, a side surface 102h, and a bottom surface 102i. In the example shown, side surface 102h is shown as being a cylindrical surface, although other shapes are possible. The first coupling part 102 may be formed from a variety of materials, for example metal materials, polymeric materials, and / or composite materials. In one example, the first coupling part is formed from a steel material as either a pow dered metal, casting, and / or a machined part. In one aspect, the first coupling part 102 is configured as a relatively rigid structure capable of transmitting torque from the electric motor shaft 24 to the second coupling part 104 without significant flexing or bending.

[0155] The second coupling part 104 includes a main body 104a defining a top surface 104d, a side surface 104e, and a bottom surface 104f. In the example shown, side surface 104e is shown as being a non-circular shape. For example, as depicted in Figures 43-47, the side surface 104e can be in the form of a polygon defining twelve side surfaces 104k. The second coupling part 104 may be formed from a variety of materials. In some examples, the second coupling part 104 is formed from an elastomeric or polymeric material such as plastic, natural or synthetic rubbers (e.g., ethylene propylene diene monomer rubber or EPDM rubber), and / or combinations thereof. In one example, the second coupling part 104 is formed from a natural rubber a Shore A hardness durometer of about 50 to 70. In one aspect, the second part 104 is configured as a structure sufficiently rigid to transmit torque from the first coupling part 102 to the third coupling part 106 while being flexible enough to elastically deform, deforming bey ond a torque or torsional shear value. In one example, the side surface 104e or outer perimeter of the second coupling part 104 can elastically deform up to about 50 foot-pounds of torquewhile the center of the second coupling part 104 is held in a stationary position. Accordingly, the second coupling part 104 may be referred to as forming an elastomeric portion of the coupling assembly 100.

[0156] As further depicted, in some embodiments, the first coupling part 102 can be integrally formed with the second coupling part 104. For example, in some embodiments, a rigid metal first coupling part 102 can be over molded with a softer polymer material forming the second coupling part 104. Together the first coupling part 102 and the second coupling part 104 form a single piece hub member 105.

[0157] The third coupling part 106, alternatively referred to as a pen phen member 107, is provided with a main body 106a defining a central aperture 106b extending along a sidewall 106c, a top surface 106d. a side surface 106e, and a bottom surface 106f. As shown, the sidewall 106c and side surface 106e are shown as being cylindrical surfaces, although other shapes are possible. The third coupling part 106 is further shown as including an interface portion 106s or mounting surface for receiving the mower blade 30 (as depicted in Figure 42). In the example shown, interface portion 106s is provided as a pair of threaded recesses. Other arrangements are possible, for example, through holes for receiving bolts. The third coupling part 106 is also shown as including a radially inw ardly extending lip 106p, formed as an extension of the top surface 104d. The lip 106p provides for an abutment surface between the second and third coupling parts 104, 106 such that the second coupling part 104 can be placed in a compressed state between the third coupling part 106 and the blade 30. This compression increases the torsional shear resistance of the second coupling part. In the example shown, sidewall 106c is shown as being a non-circular shape. For example, as depicted in Figures 48-52, a periphery’ of the sidewall 106c be in the shape of a polygon defining twelve side surfaces 106r.

[0158] The third coupling part 106 may be formed from a variety of materials, for example metal materials, plastic or polymeric materials, and / or composite materials. In one example, the third coupling part is formed from a steel material as either a powdered metal, casting, and / or a machined part. In one aspect, the third coupling part 106 is configured as a relatively rigid structure capable of transmitting torque from the first and second coupling parts 102, 104 to the mower blade 30 without significant flexing or bending. Accordingly, the third coupling part 106 may be referred to as forming a rigid portion of the coupling assembly 100.

[0159] In one aspect, the central aperture 106b of the third coupling part has a negative shape that is complementary to the positive shape defined by the side surface 104e of the second coupling part 104 such that a portion of the second coupling part 104 can be received into the central aperture 106 until the side surfaces 104k and 106r abut. Once received, the side surfaces 104k and 106r engage, due to mechanical interference between the surfaces, such that rotation of the second coupling part 104 caused by the electric motor shaft 24 will transfer torque to the third coupling part 106. Such a connection involving mechanical interference may be referred to as a fixed or rigid coupling and / or a rotationally fixed coupling. In the example shown, side surfaces 104k, 106r are provided in a twelve-sided polygon shape. However, other numbers of side surfaces and polygonal shapes may be used without departing from the concepts presented herein. For example, the side surfaces 104k, 106r can include three sides defining a triangular shape, four sides defining a rectangular or square shape, five sides defining a pentagonal shape, eight sides defining an octagonal shape, etc. Non-convex polygonal shapes, such as star shapes, may also be defined by the side surfaces 104k, 106r. Other shapes are also possible, such as non-circular shapes, oval shapes, elliptical shapes, and obround shapes. Generally polygonal shapes that would otherwise be considered as being polygon but for having rounded comers may also be used. Further, the side surfaces 104k, 106r can be formed as flat or curved sides to define any shape having no order of rotational symmetry as such a shape would inherently prevent relative rotation between the second and third coupling parts 104, 106. Due to rotational and balance concerns, a shape that is arranged to have a center or centroid aligned with the longitudinal axis X of the electric motor shaft 24 is preferred. It is noted that although a mechanical interference exists between the second and third coupling parts 104, 106, the elasticity of the second coupling part 104 can allow the second coupling part to index or cog into different positions with sufficient torsional force, such as that encountered during an impact event of the mower blade 30.

[0160] As depicted in Figures 41-42, the first retaining member 110 secures the hub member 105 to the electric motor shaft 24 of the electric motor assembly 20. The second retaining members I l la, 111b secure the mower blade 30 to the periphery member 107, enabling the mower blade 30 and periphery member 107 to rotate relative to the hub member 105 when the hub member 105 elastically deforms and / or indexes or cogs into a different position relative to the periphery member 107 due to an impact event. Inembodiments, each of the retaining members 110, I l la, 111b can include a main body 110a defining a threaded portion 110b and a head portion 110c.

[0161] With reference to Figures 39 and 42, in some embodiments, the central aperture 106b of the rigid portion can expose a bottom surface 104f of the elastomeric portion, such that at least a portion of the bottom surface 104f is contactable with the mower blade 30, when installed. For example, in some embodiments, the bottom surface 104f of the elastomeric portion can define at least one annular ring 104m extending outwardly from the bottom surface 104f in an axial direction. As best depicted in Figures 39 and 47, in some embodiments, the bottom surface 104 can include three annular rings 104m, 104n, 104r that contact the blade 30. In one aspect, the rings 104m. 104n, 104r are spaced apart by recessed portions 104s, 104t that form a cavity or portion of the bottom surface 104f that is non-contacting with the blade 30. With such a configuration, the rings 104m, 104n, 104r provide increased initial compression compliance against the blade 30, in comparison to an entirely planar bottom surface 104f, to allow for some degree of angular deflection of the mower blade 30 during an impact event. Other configurations are possible, such as those including more or fewer than three annular rings.

[0162] Referring to Figure 39A, which shows a cross-sectional view orthogonal to that shown in Figure 39, a variation of the coupling assembly 100 is presented. In one aspect, the coupling assembly 100 shown in Figure 39A includes a first coupling part 102 that has a slightly modified shape for the flange portion 102q. a second coupling part 104 with additional compliance features, and a third coupling part that is generally the same as is shown in Figure 39. In one aspect, the second coupling part 104 has compliance features in the form of additional circumferential rings 104u, 104v, separated by cavity or recessed portion 104w, that are provided on the outer perimeter side surface 104k. In the example shown, a third circumferential ring 104x is shown as being provided within the recessed portion 104w and between rings 104u, 104v. In one aspect, the rings 104u, 104v extend to contact the third coupling part 106, when the second coupling part 104 is in an undeflected or relaxed state, while ring 104x extends radially to a lesser extent and is out of contact with the third coupling part 106 in the same state. With such a configuration, the second coupling part 104 is made relatively more compliant under compression due to blade deflection in comparison to an entirely planar surface 104k. In a deflected state of the second coupling part 104, the ring 104x can come into contact with the third coupling part 106 such that the ring 104x provides resistance to further deflection of the third coupling part 106. The second coupling part 104 can also beprovided with an annular ring 104y and recess 104z on the top side of the coupling part 104 to provide for additional compliance. As the inclusion of the flange portion 102q functions to add stiffness to the second coupling part 104, the inclusion and configuration of the above-described rings provide compliance features to the second coupling part 104 to achieve selected compliance characteristics.

[0163] Referring back to Figure 39A, a vertical cross-section of the motor-blade assembly 10” is presented such that the interconnections between the electric motor shaft 24, coupling assembly 100, retaining members 110, l l la-b, and mower blade 30 are shown in further detail. As noted above, the coupling assembly 100 is assembled such that the top surface 104d abuts the underside of lip 106p, and surfaces 104e. 106r contact or abut each other. The coupling assembly 100 is installed onto the electric motor shaft 24 such that the surface defining central opening 102b surrounds and contacts the electric motor shaft 24 in a slip fit type manner using an interacting key and key way to transmit torque. The mower blade 30 is installed onto the coupling assembly 100 such that the mower blade 30 is operably coupled to the interface portion 106s of the third coupling part 106 and such that the top surface of the mower blade 30 contacts and abuts surface 104f of the second coupling part 104. By virtue of this contact, the rotation of the third coupling part 106 imparts torque and rotation onto the mower blade 30.

[0164] As is dimensioned at Figure 39A, it can be seen that the flange portion 102q of the first coupling part 102 defines an outermost dimension or diameter DI while the radially inside surface of the lip 106p of the third coupling part defies a dimension or diameter D2 that is less than diameter D 1. Accordingly, the first coupling part 102 cannot be passed through the opening defined by the lip 106p of the third coupling part 106. This configuration is advantageous in cases where an impact event causes a complete failure of the second coupling part 104 such that the second coupling part 104 no longer interconnects the first coupling part 102 to the third coupling part 106, and the attached blade 30. In such a circumstance, the flange portion 102q of the first coupling part 102 will ensure that the third coupling part 106 cannot become completely separated from the first coupling part 102 via abutment with the lip 106p. Although not dimensioned, the configuration shown at Figure 39 is similarly configured to have a flange portion 102q with a greater diameter or dimension than that defined by the radial inward edge of the lip 106p, and thus provides for this same advantage. Also, the configuration illustrated at Figure 32 may be modified to have this characteristic as well, by extending 106p in aradially inward direction, by extending 102q in a radially outward direction, or a combination of both.

[0165] With the above-described configuration, the coupling assembly 100 is advantageously able to protect the electric motor assemblies 20 and electric motor shaft 24 from impact loads caused by the mower blade 30 striking an object such as a rock, stump, or branches / limbs in multiple ways. In one scenario, when the rotating mower blade 30 strikes an object, the resulting impact torque or torque shear will momentarily rise to a level sufficient to elastically deform the second coupling part 104 in a rotational direction about a rotational axis. By allowing for elastomeric deformation and controlled slippage, the resulting angular impulse or impact torque imparted onto the electric motor shaft 24 by the impact event can be significantly reduced well ahead of any safety shutdown controls being enacted that would eventually cut power off to the electric motor assembly 20. Although the combined energy' absorption or dampening effect of these features provides certain advantages, each of these features alone is advantageous in reducing the angular impulse or impact torque imparted onto the electric motor shaft 24 at least to some degree.

[0166] In addition to the above dynamic, some types of impact events can also cause the leading edge of the mower blade 30 to deflect upward, and potentially over the impacted object, for example as illustrated at Figure 36. An impact force on the mower blade 30 of this type can impart a significant bending moment force onto the electric motor shaft 24. However, with the disclosed design, forces produced by vertical deflection of the blade are largely isolated by the elastic second coupling part 104 such that moment forces translated to the retaining member 110 are minimized. Further, and as already discussed with respect to the embodiment shown at Figures 28-32, this configuration also allows for the retaining member 110 to have a relatively short cantilevered length such that any moment forces translated to the retaining member 110 are reduced. In one aspect, the moment forces caused by vertical blade deflection can be mitigated by the elastic properties of the second coupling part 104, particularly the mechanical interference between the second coupling part 104 and the third coupling part 106. As depicted, the mower blade 30 can vertically deflect at one end to a certain degree (i.e., such that the length of the blade is at an oblique angle to the longitudinal axis X) as the second coupling part 104 will elastically compress to accommodate such movement. As shown, the blade 30 is enabled to rotate to at least some degree by the second coupling part 104, generally about an axis Y, orthogonal to the axis X, and through an angle al.In the example shown, the angle al is about 5 degrees and may be referred to as the vertical angular displacement of the blade. In view of the above, it can be appreciated that the above-described features enable the coupling assembly 100 to allow the blade 30 to rotate with respect to the motor shaft about tw o different axes (e. g. , X-axis and Y -axi s) to simultaneously minimize and absorb the torsional impact force imparted onto the motor shaft.Motor-Blade Assembly 10’”

[0167] Referring to Figures 53-70, a fourth example of a motor-blade assembly 10’” is presented. Motor-blade assembly 10’” includes the same electric motor assemblies 20 and mower blades 30 as shown and described for motor-blade assemblies 10. 10’, and 10” and can be used in conjunction with a mower 1 and deck 2, as illustrated at Figures 74 and 75, in the same manner as described above. Accordingly, the above-provided descriptions for these features are fully applicable for motor-blade assembly 10”’ and need not be repeated again in this section. Motor-blade assembly 10”’ is generally similar to motor-blade assembly 10” and includes a coupling assembly 100 comprising a first coupling part 102, a second coupling part 104, and a third coupling part 106 in which the first coupling part 102 is mounted to the shaft 24 via retaining member 110 and in which the mower blade 30 is mounted to the third coupling part 106 via retaining members I l la, 111b. Accordingly, the above-provided description for motor-blade assembly 10” is applicable to motor-blade assembly 10’” and need not be repeated again in this section. Rather, this section will focus on the differences between the motor-blade assembly 10’” and motor-blade assembly 10”. It is further noted that the below-- described features may likewise also be incorporated into the motor-blade assemblies 10, 10’, and 10”.

[0168] In one aspect, and as most easily viewed at Figures 58 to 65, the second coupling part 104 is provided with a solid outer perimeter side surface 104k rather than having circumferential rings and recesses 104u-104x. This arrangement is generally similar to that shown at Figure 39 and in contrast to that shown at Figure 39A. In some configurations, it is desirable to maximize the amount of material at this location such that more material is present betw een the end of the first coupling part 102 and the third coupling part 106, even though the slipping force betw een the coupling parts 104, 106 may be increased without changes to other parameters. Figure 58 also illustrates that the distance between the end of the first coupling part 102 and the inner surface of the thirdcoupling part 106 is slightly increased to accommodate more material for the second coupling part 104. However, even with such a modification, the dimension D2 still remains smaller than dimension DI such that the third coupling part 106 cannot separate from the first coupling part 106 in the event the second coupling part 104 loses structural integrity sufficient to retain the parts together. In some examples, to further aid in preventing such a separation and / or to enhance the connection between the first and second coupling parts, the material thickness at the end of the first coupling part can be enlarged to create a circumferential outermost ring with a greater thickness in comparison to an adjacent radially inward portion of the first coupling part 102.

[0169] With reference to Figures 69 and 73, a modification of the third coupling part 106 can be seen in which the side surfaces 106 are oriented to result in a pair of side surfaces 106r-b, passing through a centerline or axis 106x of the third coupling part 106, being orthogonal to the axis 106x and such that a pair of side surfaces 106r-a extend parallel to the axis 106x. This is in contrast to the third coupling part 106 associated with motor-blade assembly 10"’ in which the side surfaces 106 are rotated such that the axis 106x passes through that the comers between the side surfaces 106r. The configuration shown for motor-blade assembly 10”’, particularly with respect to side surfaces 106r-a, can result in an orientation of the second coupling part 104 that provides for a greater material volume at locations where force and compression can be the greatest during an impact event. With reference to Figures 71-73, this material-increasing advantage can be further enhanced by also providing the first coupling part 102 with an outer perimeter shape that corresponds to the shape of the second and third coupling parts 104, 106. For example, and as most easily viewed at Figure 73, the first coupling part 102 can be provided with flat sides 102f that are aligned with the flat sides of the first and coupling parts 104, 106, wherein the first, second, and third coupling parts 102, 104, 106 have an equal number of flat sides. By providing the first, second, and third coupling parts 102, 104, 106 with matching geometries, the thickness of the elastomeric portion is more consistent and the load during an impact event is more evenly distributed. With reference to Figures 58. 60. 66. and 68, it can also be seen that the third coupling part 106 is configured with hexagonal recesses 106t for receiving similarly shaped nuts 113. As most easily viewed at Figure 58, nuts 113 threadably receive bolts 111 to clamp the blade 30 between the third coupling part 106 and heads of the bolts 111.

[0170] In one aspect, and as most easily viewed at Figures 58-59 and 65. atop surface102r of the first coupling part 102 is provided with a chamfered or angled portion 102sthat extends at an oblique angle to the longitudinal axis X, which is in contrast to the more squared-off shape shown at Figures 39 and 39A. The first coupling part 102 is also provided with a hub or top portion 102u defining a surface 102g that is recessed from the bottom portion 22a of the electric motor, for example recessed by 0.25 inch. By providing the top surface 102r with an angled portion 102s at this location and by providing for additional clearance at the hub portion 102u, clearance between the first coupling part 102 and a bottom portion or part 22a of the electric motor assembly housing 22 is increased when the blade 30 is in a deflected state when bending of the motor shaft may occur. This configuration advantageously reduces the chance that the first coupling part 102 will undesirably contact or impact a portion of the electric motor assembly 20 during an impact event. The third coupling part 106 is similarly provided with a sloped, angled, or chamfered surface 106u at the location of the lip 106p to increase clearance between the top surface of the third coupling part 106 and the bottom portion 22a of the electric motor assembly housing 22 to reduce the chance of undesirable metal-to-metal contact between the third coupling part 106 and the housing 22.

[0171] With reference to Figure 58A, the motor-blade assembly 10 is shown as being additionally provided with a support plate 112 that is clamped between the blade 30 and the third coupling part 106. In examples, the support plate 112 has an outer perimeter that matches that of the third coupling part 106, for example the shape view able at Figures 68 and 69. The support plate 112 can also be provided with other shapes such as a circular or polygonal type shape. In one aspect, the support plate 112 is sized and shaped such that the support plate 112 is the same size or larger than the opening defined by the third coupling part 106 that receives the second coupling part 104. In one aspect, the support plate 112 is configured to cover the bottom surface of the second coupling part 104 such that the bottom surface of the second coupling part 104 is covered not left exposed. This is in contrast to the configuration shown for the motor-blade assembly 10” in which portions of the second coupling part 104 not covered by the blade 30 are left exposed. By covering the bottom surface of the second coupling part 104. the second coupling part 104 is constrained from expanding out of the third coupling part 106 which can improve performance during an impact event. Further, the second coupling part 104 is protected from impact by debris during normal operation. In some examples, the third coupling part 106 can be provided with apertures or openings in the sidewall defining the side surface 106r to allow for controlled expansion of the second coupling part 104 during an impact event.

[0172] As shown and described herein, the coupling assemblies 10. 10’, 10’', and 10”’ can advantageously ensure that the elastomeric part will not rotationally slip or cog relative to the rigid part until a torque force meeting or exceeding a maximum torque rating of the electric motor assembly 20 is applied. With such a configuration, it can be assured that the blade 30 will rotate with the motor output shaft 24 without slippage throughout the entire operational torque range of the electric motor assembly 20. Such a configuration also ensures that slippage does occur above the maximum torque rating may be indicative of a circumstance in which the blade 30 has incurred an impact event and potential damage to the electric motor assembly 20 could occur. In an illustrative and non-limiting example, an electric motor assembly has a maximum torque rating of 22 ft- 1b (foot-pounds) and the required torque to cause the elastomeric part to slip, cog, or otherwise rotate relative to the rigid part is between 35 and 55 ft-lb, a value that is also below a torque value that would damage the exemplar}7motor assembly.

[0173] Having described the preferred aspects and implementations of the present disclosure, modifications and equivalents of the disclosed concepts may readily occur to one skilled in the art. However, it is intended that such modifications and equivalents be included within the scope of the claims which are appended hereto.

Claims

CLAIMSWhat is claimed is:

1. A motor-blade assembly comprising: a. an electric motor assembly having an output shaft extending along a longitudinal axis; b. a coupling assembly secured to the output shaft, the coupling assembly including an elastomeric portion and a rigid portion; and c. a mower blade secured to the coupling assembly rigid portion by at least one retaining member; d. wherein the elastomeric portion is elastically deformable to allow the mower blade to at least partially rotate with respect to the output shaft about at least two different axes.

2. The motor-blade assembly of claim 1. wherein the elastomeric portion is received into an opening defined by the rigid portion.

3. The motor-blade assembly of claim 1, wherein the elastomeric portion and the rigid portion are separate components coupled together such that a first surface of the elastomeric portion contacts a second surface of the rigid portion, wherein relative movement between the first and second surfaces is prevented below a minimum torque force and allowed above the minimum torque force.

4. The motor-blade assembly of claim 3, wherein the minimum torque force is equal to a maximum torque rating of the electrical motor.

5. The motor-blade assembly of claim 4. wherein the maximum torque rating is at least 22 ft-lb.

6. The motor-blade assembly of claim 1, further comprising: a. a first coupling part coupled to the output shaft; b. a second coupling part defining the elastomeric portion and being coupled to the first coupling part; andc. a third coupling part defining the rigid portion and being coupled to the second coupling part.

7. The motor-blade assembly of claim 6, wherein the second and third coupling parts are coupled together such that relative movement betw een contacting surfaces of the second and third coupling parts is prevented below a minimum torque force and allowed above the minimum torque force.

8. The motor-blade assembly of claim 6, wherein a portion of the first coupling part defines a protrusion received into a complementarily shaped recess of the second coupling part.

9. The motor-blade assembly of claim 8, wherein the protrusion and recess have a noncircular shape.

10. The motor-blade assembly of claim 6. wherein the first coupling part and the second coupling part define a hub member, with the elastomeric portion defined by the second coupling part at least partially surrounding the first coupling part.

11. The motor-blade assembly of claim 10, wherein the first and second coupling parts are formed from a different material.

12. The motor-blade assembly of claim 6, wherein the coupling assembly is coupled to the output shaft by an output shaft retaining member.

13. The motor-blade assembly of claim 6, wherein the third coupling part is secured to the mower blade by a pair of retaining members.

14. The motor-blade assembly of claim 6, wherein the third coupling part includes a radially inwardly extending lip to provide an abutment surface betw een the second coupling part and the third coupling part.

15. A coupling assembly for securing a mower blade to a motor shaft, the coupling assembly comprising: a. an elastomeric portion extending along a longitudinal axis; and b. a rigid portion defining a central opening within which the elastomeric portion is received, the rigid portion defining a mounting surface for securing the mower blade; c. wherein the elastomeric portion is elastically deformable to allow the mower blade to at least partially rotate with respect to the output shaft about at least two different axes.

16. The coupling assembly of claim 15, wherein the elastomeric portion is defined by a hub member configured to be coupled to the motor shaft.

17. The coupling assembly of claim 15, wherein the rigid portion is defined by a periphery member configured to be coupled to the mower blade.

18. The coupling assembly of claim 15, wherein the rigid portion includes a radially inwardly extending lip to provide an abutment surface between the elastomeric portion and the rigid portion.

19. The coupling assembly of claim 15, wherein the elastomeric and rigid portions are coupled together such that relative movement betw een contacting surfaces of the elastomeric and rigid portions is prevented below a minimum torque force and allowed above the minimum torque force.

20. A coupling assembly for securing a mow er blade to a motor shaft, the coupling assembly comprising: a. a first coupling part extending along a longitudinal axis, the first coupling part defining a central aperture extending along the longitudinal axis and configured to receive the motor shaft; b. a second coupling part coupled with the first coupling part, the second coupling part being formed from an elastomeric material; and c. a third coupling part defining an interface portion for rotationally engaging with the mow er blade, the third coupling part being coupled with the second couplingpart such that relative movement between contacting surfaces of the second and third coupling parts is prevented below a minimum torque force and allowed above the minimum torque force.

21. The coupling assembly of claim 20, wherein the second coupling part is received into a central opening defined in the third coupling part.

22. The coupling assembly of claim 20, wherein the first coupling part and the second coupling part cooperate to define a hub member, with the second coupling part at least partially surrounding the first coupling part.

23. The coupling assembly of claim 20, wherein the third coupling part includes a radially inwardly extending lip to provide an abutment surface between the second coupling part and the third coupling part.

24. A coupling assembly for securing a mower blade to a shaft of a motor assembly, the coupling assembly comprising: a. a first coupling part extending along a longitudinal axis, the first coupling part defining a central aperture extending along the longitudinal axis and configured to receive the motor shaft; b. a second coupling part coupled with the first coupling part, the second coupling part being formed from an elastomeric material, the second coupling part having an outermost diameter; and c. a third coupling part defining an interface portion for rotationally engaging with the mower blade, the third coupling part being coupled with the second coupling part, the third coupling part defining an innermost diameter that is less than the outermost diameter of the second coupling part.

25. The coupling assembly of claim 24, wherein the first coupling part includes an integrally formed key for engaging with a corresponding slot in the motor shaft.

26. The coupling assembly of claim 24, wherein the coupling assembly further includes a pair of threaded retaining members for securing the mower blade to the rigid portion and against a portion of the second coupling part.

27. The coupling assembly of claim 24, wherein a top surface of the second coupling part has at least one angled or chamfered surface for increasing clearance between the coupling assembly and the motor assembly.

28. The coupling assembly of claim 24, wherein the second coupling part innermost diameter is defined by an inwardly extending lip that contacts an end surface of the second coupling part.

29. The coupling assembly of claim 24, further including a support plate contacting an end surface of the second coupling part and an end surface of the third coupling part.

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