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1. (WO2019049045) DUAL BLADE WALK-BEHIND MOWER
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DUAL BLADE WALK-BEHIND MOWER

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. application number 62/554,198 filed September 5, 2017, the entire contents of which are hereby incorporated by reference in its entirety.

TECHNICAL FIELD

Example embodiments generally relate to outdoor power equipment and, more particularly, relate to a walk-behind lawn mower that employs two blades that turn in opposite directions.

BACKGROUND

Yard maintenance tasks are commonly performed using various tools and/or machines that are configured for the performance of corresponding specific tasks. Certain tasks, like grass cutting, are typically performed by lawn mowers. Lawn mowers themselves may have many different configurations to support the needs and budgets of consumers. Walk-behind lawn mowers are typically relatively compact, have comparatively small engines and are relatively inexpensive. Meanwhile, at the other end of the spectrum, riding lawn mowers, such as lawn tractors, can be quite large. Riding lawn mowers can sometimes also be configured with various functional accessories (e.g., trailers, tillers and/or the like) in addition to grass cutting components. Riding lawn mowers can also be ruggedly built and have sufficient power, traction, and handling capabilities to enable operators to mow over rough terrain, if needed.

Walk-behind models are often used when smaller lots or tighter areas are to be mowed. Some, relatively simple walk-behind models may move responsive only to the pushing force provided by the operator. However, other models may provide power to either or both of the front and rear sets of wheels to assist the operator relative to providing mobility for the lawn mower. In many instances, the power may be provided, for example, via a belt system that is selectively powered off the same shaft that turns a blade for cutting grass.

In many cases, lawn mower blades have standard sizes that correspondingly dictate the width of the cutting deck used to house the cutting blade. Thus, the width of most cutting decks for walk-behind lawn mowers with a single cutting blade end up being between 20 inches and 24 inches. The width of the cutting deck generally dictates the number of passes needed to cover a certain area. Thus, for lawns that may be considered to be too small for a riding lawn mower, but would require a large number of passes to achieve full coverage using a standard

sized walk-behind mower, the customer may not find these options fully satisfying. Accordingly, it may be desirable to provide an option for customers to obtain a wider deck size in a walk-behind model.

BRIEF SUMMARY OF SOME EXAMPLES

Some example embodiments may therefore provide for a walk-behind lawn mower that uses a dual blade design to achieve a wider cutting width than standard walk-behind models. However, the wider cutting width may still be employed in connection with a rear discharge and, if desired, also with a bagging attachment that may also be operably coupled to a rear portion of the lawn mower.

In one example embodiment, a lawn mower is provided. The lawn mower may include a blade housing, a power source supported at least in part by the blade housing to selectively rotate a drive shaft, a mobility assembly including a first set of wheels and second set of wheels operably coupled to the blade housing, a first cutting blade, a second cutting blade, and a power transfer assembly. The first cutting blade and the second cutting blade may be disposed to be rotatable within the blade housing in a same plane such that respective blade orbits of the first cutting blade and the second cutting blade at least partially overlap at an overlap region. The power transfer assembly may be operably coupled to the drive shaft and configured to drive the first cutting blade and the second cutting blade to rotate within the blade housing in opposite directions and control timing of passage of the first cutting blade and the second cutting blade through the overlap region. The blade housing may be configured to be operably coupled to a bagging attachment via a first discharge tunnel disposed proximate to the first cutting blade and a second discharge tunnel disposed proximate to the second cutting blade. The first cutting blade rotates to generate a first flow path along a first side of the blade housing toward the first discharge tunnel and the second cutting blade rotates to generate a second flow path along a second side of the blade housing toward the second discharge tunnel.

In another example embodiment, a power transfer assembly for lawn mower is provided. The power transfer assembly may include a drive belt operably coupling a drive shaft of an engine of the lawn mower to at least one of a first cutting blade and a second cutting blade that may each be disposed to be rotatable in a same plane within a blade housing of the lawn mower such that respective blade orbits of the first cutting blade and the second cutting blade at least partially overlap at an overlap region. The power transfer assembly may be configured to drive the first cutting blade and the second cutting blade to rotate within the blade housing in opposite directions and control timing of passage of the first cutting blade and the second cutting blade through the overlap region.

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

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

FIG. 1 illustrates a block diagram of a walk-behind lawn mower according to an example embodiment;

FIG. 2 illustrates a perspective view of the walk-behind lawn mower according to an example embodiment;

FIG. 3 illustrates a bottom view of a cutting deck of the walk-behind lawn mower (i.e., from below the blade housing) in accordance with an example embodiment;

FIG. 4 illustrates a top view of the cutting deck according to an example embodiment;

FIG. 5 illustrates a similar view to that of FIG. 4 except that portions of the engine are removed to provide a better view of a power transfer assembly in accordance with an example embodiment; and

FIG. 6 illustrates an alternative blade housing design according to an example embodiment.

DETAILED DESCRIPTION

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

Some example embodiments described herein provide structures for improved cutting performance on a walk-behind lawn mower. In this regard, some embodiments may provide for the provision of a cutting width that can be wider than the length of a single blade (e.g., 30 inches or greater). This increased width may be provided by driving at least two blades in a

same cutting plane (e.g., substantially parallel to the ground surface) while turning the blades about axes that are spaced apart from each other by a distance that is less than a blade length apart. Thus, the coverage areas (or blade orbits) of the blades at least partially overlap. To achieve such overlap, timing control of the rotation of the blades is provided to ensure that the blades do not contact each other in the overlap region. Example embodiments may therefore also include a power transfer assembly that is configured to maintain timing control over the rotation of the blades while distributing power from the power supply of the mower to the blades. Example embodiments may also enable the clippings from the blades to be provided into a common collection assembly via dual discharge tunnels. Other structural features described herein may further enhance the performance and capabilities of the walk-behind lawn mower as described in greater detail below.

FIG. 1 illustrates a block diagram of a walk-behind lawn mower 100 of an example embodiment. The walk-behind lawn mower 100 may include an engine 110, a mobility assembly 120, and a working assembly 130. The engine 110 may be a gasoline or petrol engine in some cases. However, example embodiments could alternatively be operable with other power sources such as a battery or another electrical source (e.g., mains power). In such cases, the engine 110 could be replaced by an electric motor or other power source.

The mobility assembly 120 may, in some cases, be operably coupled to the engine 110 to enable the walk-behind lawn mower 100 to move over a ground surface upon which the walk-behind lawn mower 100 is operable via powered driving of the mobility assembly 120. However, the mobility assembly 120 could alternatively not be operably coupled to the engine 110 and therefore not be powered in other cases (e.g., moving only responsive to application of force by an operator). Thus, the mobility assembly 120 may enable the operator to move the walk-behind lawn mower 100 without power being applied to the mobility assembly 120 from the engine 110 (e.g., when the operator pushes the walk-behind lawn mower 100), or the engine 110 may at least be capable of providing power to the mobility assembly 110. The mobility assembly 120 may include wheels (e.g., front and rear wheels), or any other suitable components that can be powered to cause the walk-behind lawn mower 100 to move over the ground. If powered, the mobility assembly 120 could be front wheel drive, rear wheel drive, or all-wheel drive including petrol or electric power. If electric powered, one or more electric motors could be used to power the wheels and/or the blades independently of one another or collectively.

The working assembly 130 may be operably coupled to the engine 110 to perform a working function responsive at least in part to operation of the engine 110. As mentioned

above, the working assembly 130 could perform working functions such as cutting of grass. As such, the working assembly 130 may include at least two cutting blades that are each powered by the engine 110. The cutting blades may be turned about respective axes that are spaced apart from each other by a distance that is less than a length of either of the cutting blades (i.e., less than a blade length) in order to ensure that the blade orbits at least partially overlap.

Meanwhile, as shown in FIG. 1, the working assembly 130 may be operably coupled to the engine via a power transfer assembly 140. The power transfer assembly 140 may be configured to power each of the respective cutting blades of the working assembly 130 such that the cutting blades rotate in opposing directions (e.g., one clockwise, and the other counterclockwise) and are timing controlled to avoid collision of the cutting blades where the blade orbits overlap.

FIG. 2 illustrates a perspective view of the walk-behind lawn mower 100 of an example embodiment. FIG. 3 illustrates a bottom view of the walk-behind lawn mower 100, and FIG. 4 illustrates a top view of the walk-behind lawn mower 100. FIG. 5 illustrates a top view with portions of the engine 110 removed to expose more components of the power transfer assembly 140. The walk-behind lawn mower 100 of FIGS . 2-5 includes a blade housing 200 and a handle assembly 205 that extends rearwardly and upwardly away from the blade housing 200. The blade housing 200 may house at least a first rotatable cutting blade and a second rotatable cutting blade (e.g., first cutting blade 210 and second cutting blade 212, respectively). The first and second cutting blades 210 and 212 may each be suspended above the ground at the end of respective first and second rotatable shafts 220 and 222. The first and second rotatable shafts 220 and 222 may each be turned responsive to operation of the engine 110 via the power transfer assembly 140. Operation of the engine 110 may be initiated by a recoil starter via pulling of a recoil starter handle 230 by the operator. However, in other embodiments, the engine 110 may alternatively be started via a key, switch or other similar device.

The mobility assembly 120 of this example may be embodied in the form of front wheels 240 and rear wheels 242. A substantial portion of the weight of the walk-behind lawn mower 100 may rest on the front and rear wheels 240 and 242 (i.e., the mobility assembly 120) and the mobility assembly 120 may also provide for movement of the walk-behind lawn mower 100. In some cases, the mobility assembly 120 may be driven via power from the engine 110, as described above. However, the operator may also simply push the walk-behind lawn mower 100 to cause the front and rear wheels 240 and 242 of the mobility assembly 120 to rotate over the ground.

In some examples, the front and rear wheels 240 and 242 may be adjustable in their respective heights. Adjusting the height of the front wheels 240 and/or the rear wheels 242 may be employed in order to provide a level cut and/or to adjust the height of the first and second cutting blades 210 and 212, which are held to rotate in a common plane that is substantially parallel to the ground. The height adjustments may be made either locally or via remote wheel height adjustment.

Rotation of the cutting blades may generate grass clippings, and/or other debris that may be ejected from the blade housing 200. In some cases, the clippings/debris may be ejected from a side or rear of the blade housing 200. In one embodiment, the first and second cutting blades 210 and 212 turn in opposite directions and away from the center-rear of the cutting deck. Accordingly, in this embodiment, ejection may most efficiently be accomplished from opposing sides of the blade housing 200. Rear discharge may be preferred in some cases. When rear discharge is employed, a bagging attachment 250 may be operably coupled to a rear portion (e.g., between the rear wheels 242) of the blade housing 200 to collect discharged clippings/debris. However, the bagging attachment 250 may receive the clippings/debris through two respective discharge tunnels (e.g., first discharge tunnel 260 and second discharge tunnel 262) that correlate to the respective ones of the first and second cutting blades 210 and 212. In particular, for example, the first discharge tunnel 260 may be provided to receive clippings/debris discharged from the first cutting blade 210 on one rear side of the blade housing 200 (e.g., by one of the rear wheels 242), and the second discharge tunnel 262 may be provided to receive clippings/debris discharged from the second cutting blade 212 on the opposite rear side of the blade housing 200 (e.g., by the other rear wheel 242). The first and second discharge tunnels 260 and 262 may be fixed to the blade housing 200 (e.g., as molded portions formed into the blade housing 200, or as components that are welded, bolted or otherwise fixedly attached to the blade housing 200), or may be separate portions (e.g., plastic components) that are removably attachable to the blade housing 200.

In the example of FIG. 3, the first and second discharge tunnels 260 and 262 are operably coupled to guide vanes 270 formed in the blade housing 200. The guide vanes 270 may be structural formations of walls and/or recesses that are provided to guide or direct the flow of clippings/debris toward the bagging attachment 250. The guide vanes 270 may therefore be used to facilitate direction of the clippings/debris into the first and second discharge tunnels 260 and 262. In this example, the guide vanes 270 are integrally formed in the blade housing 200. However, in other examples, the guide vanes 270 may be formed using metal, plastic, or other rigid walls or surfaces that are positioned to extend substantially perpendicular to the top surface or wall of the blade housing 200 to direct clippings/debris or otherwise direct flow within the blade housing 200 in an advantageous way.

Referring again to FIG. 3, some example embodiments may provide the first and second rotatable shafts 220 and 222 such that they equidistant from a longitudinal centerline of the walk-behind lawn mower 100 and mirrored in position with respect to the longitudinal centerline of the walk-behind lawn mower 100. Thus, the first and second rotatable shafts 220 and 222 may each be also equidistant from the front end of the walk-behind lawn mower 100 or otherwise each extending in a plane that is substantially parallel to a direction of extension of both front and rear axles that extend between the front and rear wheels 240 and 242, respectively. As such, the blade orbits of the first and second cutting blades 210 and 212 may be symmetrical with respect to the longitudinal centerline of the walk-behind lawn mower 100 and mirrored in position with respect to the longitudinal centerline of the walk-behind lawn mower 100. However, in other embodiments, such a symmetrical structure may not be employed. Thus, for example, the first and second cutting blades 210 and 212 could be staggered such that the first rotatable shaft 220 is located slightly forward (or rearward) of the second rotatable shaft 222 so that continuous coverage can be achieved across a width of the blade housing 200 without necessarily needing to employ an overlap region or control timing of blades entering such overlap region.

In an embodiment in which a symmetrical cutting blade arrangement is employed, the guide vanes 270 may also be symmetrical. Moreover, to the extent that baffles are included in an exemplary design, full baffles 272 (e.g., baffles that extend downward from a top portion of the blade housing 200 and have a length substantially equal to a length of the sidewalls of the blade housing 200) may be provided to outline portions of the blade orbits where the blade orbits do not overlap. Partial baffles 274 (e.g., baffles that extend downward from the top portion of the blade housing 200 by a length less than the distance between the top portion of the blade housing 200 and the plane in which the first and second cutting blades 210 and 212 rotate) may be provided to direct flow at other portions of the blade housing 200.

As discussed above, the power transfer assembly 140 may be configured to control timing of rotation of the first and second cutting blades 210 and 212 to ensure that the blade orbits can overlap without conflict or collision. The first cutting blade 210 may be configured to rotate about the first rotatable shaft 220 responsive to provision of power from the engine 110 via a drive belt 280. In particular, a drive shaft 281 of the engine 110 may be turned responsive to operation of the engine 110. The drive shaft 281 may be operably coupled to a drive pulley. The drive belt 280 may be operably coupled to the drive pulley disposed at the engine 110 and a shaft pulley 282 that may be operably coupled to the first rotatable shaft 220. The first rotatable shaft 220 and the shaft pulley 282 may each also be operably coupled to a first gear 290. Thus, for example, the first gear 290 and the shaft pulley 282 may be adjacent to one another and rotate about the first rotatable shaft 220.

The power for rotation of the first rotatable shaft 220, which is driven by the engine 110 via the drive belt 280, may be transferred to second rotatable shaft 222 via the power transfer assembly 140 in a way that also controls timing of the passage of each of the first and second cutting blades 210 and 212 through an overlap region at which the blade orbits of the first and second cutting blades 210 and 212 overlap. In this regard, the timing is controlled to ensure that only one of the first and second cutting blades 210 and 212 is in the overlap region at any given time. One way to achieve this goal is to orient the first and second cutting blades 210 and 212 such that they are substantially perpendicular to each other when either blade is parallel to the longitudinal centerline of the longitudinal centerline of the walk-behind lawn mower 100. Thus, referring to FIG. 3, in which the first cutting blade 210 is substantially parallel to the longitudinal centerline of the walk-behind lawn mower 100, the second cutting blade 212 extends substantially perpendicular to the first cutting blade 210 and to the longitudinal centerline of the walk-behind lawn mower 100. When the second cutting blade 212 rotates to a position at which the second cutting blade 212 is substantially parallel to the longitudinal centerline of the walk-behind lawn mower 100, the first cutting blade 210 will have rotated to a position to be substantially perpendicular to the second cutting blade 212 and to the longitudinal centerline of the walk-behind lawn mower 100.

In the example of FIGS. 2-5, the power transfer assembly 140 maintains the timing control over passage through the overlap region while also controlling rotation of the first and second cutting blades 210 and 212 in opposite directions. In this regard, the first cutting blade 210 rotates clockwise (when viewed from below) while the second cutting blade 212 rotates counterclockwise (when viewed from below), while sweeping clippings/debris outwardly to direct the clippings/debris along outer edges or sides of the blade housing 200 before discharge. Thus, the clippings/debris follow respective flow paths that pass along opposite sides of the blade housing 200 (e.g., not through the middle of the blade housing 200) rearward toward respective ones of the first and second discharge tunnels 260 and 262. The structures of the power transfer assembly 140 of this example that control timing and rotation of the first and second cutting blades 210 and 212 include the first gear 290, a second gear 292, a third gear 294, and a fourth gear 296. The fourth gear 296 is operably coupled to the second rotatable shaft 222, and the second and third gears 292 and 294 are each operably coupled to respective intermediate shafts that are equidistant from each other and from the respective adjacent one of either the first rotatable shaft 220 or the second rotatable shaft 222. Thus, the first and second rotatable shafts 220 and 222 may be provided in a linear arrangement with the intermediate shafts of the second and third gears 292 and 294 such that a line passing through all four shafts may be substantially perpendicular to the longitudinal centerline of the walk-behind lawn mower 100.

Although not required, it may be the case that only the first and second rotatable shafts 220 and 222 penetrate through the blade housing 200. Thus, the intermediate shafts may only extend upwardly away from the blade housing 200. In this example, each of the first gear 290, the second gear 292, the third gear 294 and the fourth gear 296 may lie in a same plane. Moreover, the plane in which the first gear 290, the second gear 292, the third gear 294 and the fourth gear 296 lie may be substantially parallel to a plane in which the blade orbits of each of the first and second cutting blades 210 and 212 lie (which is also substantially parallel to the ground).

The power transfer assembly 140 of this example uses four gears, however, any even number of gears could be employed where a diameter of each gear (d) is selected such that the diameter (d) is equal to a length (L) between the first and second rotatable shafts 220 and 222 divided by a number of gears (n) minus 1 (i.e., <i=L/(n-l)). The even number of gears ensures that the second cutting blade 212 will turn in the opposite direction to the direction of rotation of the first cutting blade 210. In this regard, and in reference to FIG. 5, if the first cutting blade 210 appears to rotate clockwise when viewed from below, then the first rotatable shaft 220, the first gear 290, and the shaft pulley 282 would appear to rotate counterclockwise when viewed from above. The second gear 292 turns in a direction opposite the direction of rotation of the first gear 290. The third gear 294 is therefore driven by the second gear 292 to turn in a direction opposite the direction of rotation of the second gear 292 and in the same direction of rotation as the first gear 290. The fourth gear 296 is driven by the third gear 294 to turn in a direction opposite the direction of rotation of the third gear 294 (and first gear 290), and in the same direction of rotation as the second gear 292. Thus, the fourth gear 296 and the second rotatable shaft 222 turn in a direction opposite to the direction of rotation of the first gear 290 and the first rotatable shaft 220. Moreover, since the first, second, third and fourth gears 290, 292, 294 and 296 stay positively engaged with respective adjacent gears, the timing differences established when the first and second cutting blades 210 and 212 are attached to the first and second rotatable shafts 220 and 222, respectively, are maintained unchanged during operation

of the walk-behind lawn mower 100 and clippings/debris are pushed to opposite side edges of the blade housing 200 before discharge.

Although the use of the first, second, third and fourth gears 290, 292, 294 and 296, and the shaft pulley 282 and drive belt 280 to instantiate the power transfer assembly 140 of this example results in desired timing control and turning of the first and second cutting blades 210 and 212 in opposite directions, it should be appreciated that other structures could alternatively be employed to achieve similar results. For example, separate electric motors powered by battery and configured to turn the blades, separate belts/pulleys, gear arrangements with different sized gears, etc., may alternatively be employed.

Regardless of the method used to turn the first and second cutting blades 210 and 212, the power transfer assembly 140 provides for coupling power from a single source (e.g., the drive shaft 281) to rotate the first and second cutting blades 210 and 212 in opposite directions while enabling the first and second cutting blades 210 and 212 to each pass through the overlap region without collision. Moreover, in an example embodiment, the rotation of the first and second cutting blades 210 and 212 may create airflow within the blade housing 200 to move clippings/debris outwardly and rearwardly into respective discharge tunnels (e.g., the first and second discharge tunnels 260 and 262) that lead into the bagging attachment 250 disposed at a rear portion of the blade housing 200.

FIG. 6 illustrates an alternative blade housing 300 design according to an example embodiment. The first and second cutting blades 210 and 212 are also shown in FIG. 6, and may operate as described above. However, the blade housing 300 may have a different shape with full baffles 310 and partial baffles 312 in different arrangements in order to provide different flow dynamics. In some cases, the discharge tunnels may be plastic removable tunnels (not shown in FIG. 6 as they are presently removed) that may be added to side discharge portions of the blade housing 300 in contrast to the rear discharge embodiment shown in FIGS. 2-5. Thus, FIG. 6 illustrates that different flow dynamics may be achieved in respective different embodiments and different discharge options could be accommodated either with a back fit option (e.g., removable tunnels inserted in rear or side discharge ports) or by integrally forming discharge tunnels in blade housings. Example embodiments could therefore be employed in connection with a bagging attachment for either side or rear discharge blade housings.

Accordingly, an example embodiment may provide a lawn mower and corresponding power transfer assembly for the lawn mower. The lawn mower may include a blade housing, a power source supported at least in part by the blade housing to selectively rotate a drive shaft, a mobility assembly including a first set of wheels and second set of wheels operably coupled to the blade housing, a first cutting blade, a second cutting blade, and the power transfer assembly. The first cutting blade and the second cutting blade may be disposed to be rotatable within the blade housing in a same plane such that respective blade orbits of the first cutting blade and the second cutting blade at least partially overlap at an overlap region. The power transfer assembly may be operably coupled to the drive shaft and configured to drive the first cutting blade and the second cutting blade to rotate within the blade housing in opposite directions and control timing of passage of the first cutting blade and the second cutting blade through the overlap region. The blade housing may be configured to be operably coupled to a bagging attachment via a first discharge tunnel disposed proximate to the first cutting blade and a second discharge tunnel disposed proximate to the second cutting blade. The first cutting blade rotates to generate a first flow path along a first side of the blade housing toward the first discharge tunnel and the second cutting blade rotates to generate a second flow path along a second side of the blade housing toward the second discharge tunnel.

In an example embodiment, the lawn mower and/or power transfer assembly may include additional, optional features, and/or the features described above may be modified or augmented. The additional or optional features and/or augmentations or modifications may be combined in any desirable way. Some examples of modifications, optional features and augmentations are described below. In this regard, for example, in some cases, (1) the first and second discharge tunnels mirror each other with respect to a longitudinal centerline of the lawn mower. Alternatively or additionally, (2) the first and second discharge tunnels may be removably or fixedly mounted to the blade housing. Alternatively or additionally, (3) the blade housing may further include guide vanes configured to direct clippings/debris toward respective ones of the first and second discharge tunnels. In some embodiments, (4), the blade housing may include full length baffles outlining portions of the blade orbits of the first and second cutting blades other than at the overlap region. Alternatively or additionally, (5) the blade housing may include partial length baffles inside the blade orbits of the first and second cutting blades to direct flows of clippings/debris within the blade housing. In some cases, (6) the first cutting blade may be operably coupled to a first rotatable shaft and the second cutting blade may be operably coupled to a second rotatable shaft. In such an example, the power transfer assembly may include a drive belt operably coupled between only one of the first rotatable shaft or the second rotatable shaft and the drive shaft. In some embodiments, (7) the first rotatable shaft and the second rotatable shaft may be operably coupled to each other such that timing of passage of the first cutting blade and the second cutting blade through the overlap region is controlled to prevent the first and second cutting blades from being in the overlap region at the same time. In some cases, (8) in response to the first cutting blade being substantially perpendicular to a longitudinal centerline of the lawn mower, the second cutting blade is disposed substantially parallel to the longitudinal centerline and the first cutting blade, and in response to the second cutting blade being substantially perpendicular to the longitudinal centerline, the first cutting blade is disposed substantially parallel to the longitudinal centerline and the second cutting blade. In an example embodiment, (9) the first rotatable shaft may be driven by the drive shaft, and the second rotatable shaft may be driven via the first rotatable shaft.

In some embodiments, any or all of (1) to (9) may be employed and the blade orbits may be symmetrical about a longitudinal centerline of the lawn mower, and a first rotatable shaft to which the first cutting blade may be operably coupled and a second rotatable shaft to which the second cutting blade is operably coupled are each equidistant from the longitudinal centerline of the lawn mower. In an example embodiment, any or all of (1) to (9) may be employed and the power transfer assembly comprises an even number of gears. In some cases, any or all of (1) to (9) may be employed and the lawn mower may be a walk-behind lawn mower.

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