Patent Description:
Some such surface maintenance machines are commercially available "micro" rider machines, allowing an operator to stand on a platform. Some of these machines have a centrally located front wheel and two rear wheels, with the operator platform inset between the rear wheels. In such machines, a common way to steer and propel a wheel (typically the centrally located front wheel) is by using a wheel motor rotatable by means of a steering linkage. In such machines, the location of the center of gravity should be accounted for to provide stability during normal vehicle operation (e.g., braking during turning).

Moreover, known mechanisms to steer and propel three-wheeled machines, such as using independently driven wheels (e.g., differential steering), can often lead to higher complexity. Prior three wheeled machines with two front wheels and one rear wheel have used steerable rear wheels which may lead to rear swing, which may cause portions of the vehicle to move in a direction opposite to the direction of turn. Rear swing may be undesirable when maneuvering next to objects (walls, curbs, buildings, people, etc.). Another known mechanism for three-wheeled vehicles includes a steerable single front wheel and two rear wheels propelled by a transaxle. This mechanism does not allow for a zero turn (e.g., a turn of zero turning radius). Other ways of steering a three-wheeled machine with two front wheels and a single rear wheel machine include providing a steering linkage connecting the two front wheels. As the steering linkage does permit sufficient steering rotation, such a mechanism would not permit a zero turn. <CIT> describes a floor cleansing machine, particularly for industrial use, comprising a chassis which supports floor cleansing means in a downward region; the chassis further defines a driver's seat and is provided at the rear with at least one pair of lateral wheels and at the front with a steerable central wheel; the chassis is provided with at least one pair of auxiliary lateral ground supports which are arranged on mutually opposite sides with respect to the steerable central wheel. <CIT> describes a floor cleaning machine with at least two movable squeegees to provide coverage of the liquid applied to the floor in a path with the squeegees extending beyond the outer perimeter sides of the liquid path both during straight ahead movement and during turning maneuvers. The squeegee assemblies are carried by a chassis. A floor scrubbing device is provided to apply liquid to the floor and to mix dirt on the floor with the applied liquid. A liquid pickup device is also provided to remove the applied liquid from the floor at a position adjacent to each of the squeegee assemblies. <CIT> describes an ultra-high speed burnisher with a pair of opposing polygonal burnishing pads. The polygonal pads may be Y-shaped, flower-shaped, hexagonal-shaped, daisy-shaped, elongate like a lawnmower blade, triangular-shaped, square-shaped, pentagonal-shaped or cross-shaped. A method for producing polygonal pads and the resulting product of this method are also described. A method for burnishing the floor of a store with at least <NUM>,<NUM> square feet (<NUM>,<NUM> square meter) of floor space on a single battery charge is also described.

In one aspect, this disclosure is directed to a surface maintenance machine as defined in claim <NUM>, with preferred or optional features as set put in the dependent claims.

<FIG> is a perspective view of an exemplary surface maintenance machine <NUM>. <FIG> illustrates the surface maintenance machine <NUM> with some body panels removed for clarity. In the illustrated embodiment shown in <FIG>, the surface maintenance machine <NUM> is s a ride-on machine <NUM>. The surface maintenance machine <NUM> can perform maintenance tasks such as sweeping, scrubbing, polishing (burnishing) a surface. The surface can be a floor surface, pavement, road surface and the like. Embodiments of the surface maintenance machine <NUM> include components that are supported on a mobile body <NUM>. As best seen in <FIG>, the mobile body <NUM> comprises a frame <NUM> supported on wheels for travel over a surface, on which a surface maintenance operation is to be performed. The mobile body <NUM> may include operator controls (not shown) and a steering control such as a steering wheel <NUM> such that an operator <NUM> can turn the steering wheel <NUM> and control the speed of the machine <NUM> without having to remove the operator's hands from the steering wheel <NUM> using means well-known in the art. The machine can perform maintenance on a maintenance path which can have an area corresponding to an envelope defined by the front surface <NUM>, back surface <NUM> and two lateral surfaces <NUM> and <NUM> of the machine <NUM> as the machine travels on a surface <NUM>.

The surface maintenance machine <NUM> can be powered by an on-board power source such as one or more batteries or an internal combustion engine (not shown). The power source can be proximate the front of the surface maintenance machine <NUM>, or it may instead be located elsewhere, such as within the interior of the surface maintenance machine <NUM>, supported within the frame <NUM>, and/or proximate the rear of the surface maintenance machine <NUM>. Alternatively, the surface maintenance machine <NUM> can be powered by an external electrical source (e.g., a power generator) via an electrical outlet or a fuel cell. The interior of the surface maintenance machine <NUM> can include electrical connections (not shown) for transmission and control of various components.

While not shown in detail in <FIG>, the surface maintenance machine <NUM> includes a maintenance head assembly <NUM>. The maintenance head assembly <NUM> houses one or more surface maintenance tools such as scrub brushes, sweeping brushes, and polishing, stripping or burnishing pads, and tools for extracting (e.g., dry or wet vacuum tools). For example, the maintenance head is a cleaning head comprising one or more cleaning tools (e.g., sweeping or scrubbing brushes). Alternatively, the maintenance head is a treatment head comprising one or more treatment tools (e.g., polishing, stripping or buffing pads). Many different types of surface maintenance tools are used to perform one or more maintenance operations on the surface <NUM>. The maintenance operation can be a dry operation or a wet operation. Such maintenance tools include sweeping, scrubbing brushes, wet scrubbing pads, polishing/burnishing and/or buffing pads. Additionally, one or more side brushes for performing sweeping, dry or wet vacuuming, extracting, scrubbing or other operations can be provided. The maintenance head assembly <NUM> can extend toward a surface on which a maintenance operation is to be performed. For example, the maintenance head assembly <NUM> can be attached to the base of the surface maintenance machine <NUM> such that the head can be lowered to an operating position and raised to a traveling position. The maintenance head assembly <NUM> is connected to the surface maintenance machine <NUM> using any known mechanism, such as a suspension and lift mechanism such as those illustrated in <CIT>.

In some embodiments, the interior of the surface maintenance machine <NUM> can include a vacuum system (not shown) for removal of debris from the surface. In such embodiments, the interior can include a fluid source tank (not shown) and a fluid recovery tank (not shown). The fluid source tank can include a fluid source such as a cleaner or sanitizing fluid that can be applied to the surface <NUM> during treating operations. The fluid recovery tank holds recovered fluid source that has been applied to the surface <NUM> and soiled. The interior of the surface maintenance machine <NUM> can include passageways (not shown) for passage of debris and dirty liquid. In some such cases, the vacuum system can be fluidly coupled to the recovery tank for drawing dirt, debris or soiled liquid from the surface. The vacuum system may comprise a vacuum-assisted squeegee (to be described with respect to <FIG>) mounted to extend from a lower rearward portion <NUM> of machine <NUM>. Fluid, for example, clean liquid, which may be mixed with a detergent, can be dispensed from the scrubbing fluid tank to the floor beneath machine <NUM>, in proximity to the scrubbing brushes, and soiled scrubbing fluid is drawn by the squeegee centrally, after which it is suctioned via a recovery hose into the recovery tank. Machine <NUM> can also include a feedback control system to operate these and other elements of machine <NUM>, according to apparatus and methods which are known to those skilled in the art.

In alternative embodiments, the surface maintenance machines <NUM> may be combination sweeper and scrubber machines <NUM>. In such embodiments, in addition to the elements describe above, the machines <NUM> may either be an air sweeper-scrubber or a mechanical sweeper-scrubber. Such machines <NUM> can also include sweeping brushes (e.g., rotary broom) extending toward a surface (e.g., from the underside of the machine <NUM>), with the sweeping brushes designed to direct dirt and debris into a hopper. In the cases of an air sweeper-scrubber, the machine <NUM> can also include a vacuum system for suctioning dirt and debris from the surface <NUM>. In still other embodiments, the machine <NUM> may be a sweeper. In such embodiments, the machine <NUM> may include the elements as described above for a sweeper and scrubber machine <NUM>, but would not include the scrubbing elements such as scrubbers, squeegees and fluid storage tanks (for detergent, recovered fluid and clean liquid).

In use, an operator may ride the machine <NUM> in a standing position and stand on an operator platform <NUM>. The operator platform <NUM> can optionally include one or more foot pedals <NUM>, <NUM> for engaging with maintenance tools <NUM> extending from below the machine <NUM>, as will be described further below. Continuing with the illustrated embodiment of <FIG>, advantageously, the machine <NUM> includes an operator console <NUM> provided on the machine <NUM> body. The operator console <NUM> can include controls for steering, propelling, and controlling various operations of the machine <NUM>. For instance, the operator console <NUM> can include a steering control such as a steering wheel <NUM> such that an operator standing on the operating platform can grasp and turn the steering wheel <NUM> to turn the machine <NUM>. Further, the operator console <NUM> can include speed controls (e.g., such as a knob, not shown) that can control the speed of the machine <NUM> without having to remove the operator's hands from the steering wheel <NUM> using means well-known in the art. As is apparent from the foregoing disclosure, the operator console <NUM> can be approximately at the waist-level of an adult operator standing on the operating platform. Such embodiments allow a compact vehicle design while providing easy to use controls to control the operation of the machine <NUM>.

Continuing with <FIG>, the surface maintenance machine <NUM> according to some embodiments can have an overall width <NUM> of less than about three feet (<NUM>,<NUM> meter). For example, the machine <NUM> can have an overall width <NUM> of less than about <NUM> inches (about <NUM>). As used herein, the term "width" refers to the distance between lateral surfaces <NUM>, <NUM>(e.g., perpendicular to the longitudinal centerline and/or the transverse centerline <NUM>) of the machine <NUM>. The lateral confines of the machine <NUM> in such cases are within about <NUM> inches (about <NUM>). In such cases, the machine <NUM> has a maintenance path corresponding to an envelope of the surface in contact with the maintenance head assembly <NUM> during a surface maintenance operation. The envelope as used herein can be the area defined by the front surface <NUM>, back surface <NUM> and two lateral surfaces <NUM> and <NUM> of the machine <NUM>. The maintenance path can have a width (e.g., distance between lateral surfaces <NUM> and <NUM>) of between about <NUM> inches and about <NUM> inches (between about <NUM> and about <NUM>). Such machines <NUM> are sometimes referred to as "micro-riders" because of their compact sizes. While an exemplary micro-rider machine is illustrated, the embodiments disclosed herein can apply similarly to machines of any sizes and configuration.

With continued reference to <FIG>, in certain embodiments, the machine <NUM> comprises three wheels. In the illustrated embodiment, the machine <NUM> comprises a steerable front wheel <NUM>, and a non-steerable front wheel <NUM>. As shown herein, the steerable front wheel <NUM> and non-steerable front wheel <NUM> are positioned toward a lower front portion <NUM> to the front of a transverse centerline <NUM> of the machine <NUM> when the machine <NUM> is moving in a forward direction <NUM>. As illustrated herein, the transverse centerline corresponds to a line positioned about one-half of the distance <NUM> between the front wheels <NUM>, <NUM> and rear wheel <NUM>. Also illustrated in <FIG> is a rear wheel <NUM> positioned near the lower rearward portion <NUM> to the rear of the transverse centerline <NUM> of the machine <NUM> when the machine <NUM> is moving in a forward direction <NUM>. In some cases, rear wheel <NUM> comprises a unitary wheel (e.g., one-piece design). For example, in some cases, there may be no other wheels to the rear of the transverse centerline <NUM> except for a single rear wheel <NUM>. While the rear wheel <NUM> is shown as being centered on the longitudinal centerline <NUM> of the machine, small offsets from the central location are still contemplated by the illustrated embodiments, and the rear wheel <NUM> may not have equal portions extending on opposite sides of the longitudinal centerline <NUM>.

In the embodiments illustrated herein, the front wheel <NUM> is steered, while the non-steerable front wheel <NUM> trails along and turns as the machine <NUM> is turned. Alternatively, both front wheels <NUM>, <NUM> can be steered. In embodiments disclosed herein, at least one of the front wheels <NUM>, <NUM> is steered, while the rear wheel <NUM> may or may not be steered. While the following description is described relative to steering the front wheel <NUM>, it should be noted that both front wheels <NUM>, <NUM>, and rear wheels <NUM> can be steered in a manner similar to the operation described relative to front wheel <NUM> below.

The machine <NUM> comprises a steering assembly having a steering wheel <NUM> coupled to (e.g., via a steering column and rack and pinion steering mechanism, or other such steering mechanisms known in the art) the steerable front wheel <NUM>. By turning the steering wheel <NUM>, the front wheel <NUM> can be turned to turn the machine <NUM> around a corner. The front wheel <NUM> can be turned by any angle to complete a turn having a desired angle (e.g., less than or equal to <NUM> degrees), as will be explained further with respect to <FIG>. Such embodiments can be beneficial in allowing a greater degree of freedom for the steerable-front wheel <NUM>, thereby permitting the machine <NUM> to be used for maintaining surfaces in narrow spaces (e.g., hallways or aisles with width under about three feet (about <NUM>), enter or leave doorways having a width of about <NUM> inches (about <NUM>), perform a zero turn in an aisle of width about <NUM> inches (about <NUM>) and the like).

Referring now to <FIG>, the machine <NUM> can include a motive source <NUM> for providing motive force to the steerable front wheel <NUM> to drive the machine <NUM> on a surface <NUM>. The motive source <NUM> can be positioned proximal to and coupled to (e.g., directly or via a transmission system) the front wheels <NUM>, <NUM>. As such, the illustrated embodiments represent a front wheel <NUM> drive and a front steered vehicle. The rear wheel <NUM> in such cases can be neither steered nor propelled, thereby allowing for the rear wheel <NUM> to remain substantially stationary when the machine <NUM> is turned by an operator. The rear wheel <NUM> in some embodiments can be a non-marking wheel (e.g., made of a material that is resilient relative to the frame <NUM> of the machine <NUM>) to reduce wheel marks on the surface <NUM> being maintained. For example, as shown in <FIG>, the machine <NUM> can include a motor coupled the steerable front wheel <NUM> to drive the front wheel <NUM>. In such cases, the non-steerable front wheel <NUM> may not be propelled by the motive source <NUM>. For example, the non-steerable front wheel <NUM> can be a caster and remain non-steered and non-driven during normal operation of the machine <NUM> and merely turn or rotate to facilitate moving the machine <NUM>. As will be further explained below, embodiments such as those illustrated in <FIG> can offer improved stability and reduce "rear swing" over other three-wheeled drive and steering systems of machines <NUM> known in the art, especially when the machine <NUM> is being turned around a sharp turn (e.g., <NUM> degrees or more) with respect to the forward direction <NUM> of the machine <NUM>.

Alternatively, the motive source <NUM> can propel the rear wheel <NUM>. In such cases, the rear wheel <NUM> may or may not be steerable, while one or more of the front wheels <NUM>, <NUM> can be steerable. Any configuration of steering and propelling of the wheels are contemplated, and the embodiments described herein are not limited to the illustrated embodiment shown in <FIG>. For example, the two front wheels <NUM>, <NUM> can each steerable by a steering mechanism (e.g., a single steering mechanism steering two front wheels). Similarly, both front wheels <NUM>, <NUM> can be propelled by the motive source <NUM> for providing motive force to the front wheels. Alternatively, at least one of the front wheels <NUM>, <NUM> are steerable by a steering mechanism, and the rear wheel <NUM> is non-steerable, but can be propelled by a motive source for providing motive force to the rear wheel <NUM>.

During use, an operator may have to turn the machine <NUM> to perform a surface <NUM> maintenance operation, or to travel to a different surface. For example, an operator may turn the machine <NUM> less than or equal to about <NUM> degrees (e.g., a left turn, a right turn or a U-turn) from the forward direction <NUM> in a narrow aisle. In such cases, to improve the stability of the machine <NUM> and also to reduce rear swing, in the embodiments described herein, the rear wheel <NUM> is neither driven by the motive source <NUM>, nor steered. The machine therefore pivots about a stationary pivot point <NUM> when turned. When an operator turns the machine <NUM> by a desired angle (e.g., <NUM> degrees), the machine <NUM> turns about the stationary pivot point <NUM> by the desired angle. As the rear wheel <NUM> is not driven or steered, its chances of traversing a path having a radius of curvature different from (e.g., wider than) the radius of curvature of the turn are reduced. Such embodiments reduce rear swing and any damage due to collision of the rear of the machine <NUM> with any obstruction to the rear of the transverse centerline <NUM> of the machine <NUM> (e.g., walls, etc.) as the machine <NUM> is cleaning in the proximity of an obstruction, such as along a wall or around a corner.

Continuing with the above, the stationary pivot point is at the intersection of a longitudinal centerline <NUM> of the machine and a rotational axis <NUM> of the rear wheel <NUM>. In some cases, the rear wheel <NUM> can be an idler wheel. In such cases, the rotational axis <NUM> of the rear wheel <NUM> is parallel to the transverse centerline <NUM> of the machine when the machine turns. Alternatively, in some embodiments, the rear wheel <NUM> can pivot to a limited extent. In such cases, the rotational axis <NUM> of the rear wheel <NUM> is passively pivotable relative to the transverse centerline <NUM> of the machine. In such cases, the rear wheel <NUM> is non-steerable and is not propelled, but may pivot to a limited extent similar to a caster. Still further, the rear wheel <NUM> can be actively steered (e.g., by the steering mechanism and/or a transaxle) and/or propelled (e.g., by the motive source <NUM>). In examples where the rear wheel <NUM> is actively steered, the rotational axis <NUM> is actively pivotable with respect to the transverse centerline <NUM> of the machine by a steering mechanism and/or a transaxle.

With continued reference to <FIG>, the rear wheel <NUM> is generally centered about a longitudinal centerline <NUM> of the machine <NUM> such that the rear wheel <NUM> extends on two opposite sides of the longitudinal centerline <NUM>. As used herein "generally centered" includes small offsets of the rear wheel <NUM> relative to the longitudinal centerline such that portions of the rear wheel <NUM> that extend on either side of the longitudinal centerline <NUM> may not be exactly equal. As illustrated herein, the longitudinal centerline <NUM> can correspond to a line positioned about one-half of the distance <NUM> between the front wheels <NUM>, <NUM>. The steerable and non-steerable front wheels <NUM>, <NUM> may be positioned symmetrically or asymmetrically on either side of the longitudinal centerline <NUM> of the machine <NUM>. In such cases, as best seen in <FIG>, the front and rear wheels <NUM>, <NUM>, <NUM> are arranged in a triangular orientation. When viewed from the bottom, each of the front and rear wheels <NUM>, <NUM>, <NUM> form a vertex of the triangle <NUM>, with the sides <NUM>, <NUM> of the triangle <NUM> tapering from the front of the machine <NUM> to the rear. As will be described further below, such embodiments with two front wheels <NUM>, <NUM> and a single rear wheel <NUM> can offer less sensitivity to center of gravity position over conventional three-wheeled surface maintenance machines (e.g., such as conventional machines having a single front wheel and two rear wheels). In such embodiments, there may be no other wheel other than the rear wheel <NUM> positioned to the rear of the transverse centerline of the machine that is inline with the rotational axis <NUM> of the rear wheel. Accordingly, the rear wheel <NUM> is centrally located such that it is symmetrically positioned on the longitudinal centerline <NUM> of the machine. In such a configuration, the machine <NUM> has three contact points with the surface <NUM>, each contact point corresponding to each of the front wheels <NUM>, <NUM> and the rear wheel <NUM>. The contact points define a contact plane such that no other wheels except the three wheels <NUM>, <NUM>, and <NUM> contact the surface <NUM> at the contact plane.

As referred to previously, the front wheel <NUM> is coupled to a steering wheel <NUM> to turn the machine <NUM> by a desired angle, while the rear wheel <NUM> remains stationary while turning. For instance, as the machine <NUM> is turned, it may pivot about the center of the stationary rear wheel <NUM>. As shown in <FIG>, the steerable front wheel <NUM> (and the motive source <NUM> coupled thereto) can be offset with respect to the longitudinal centerline <NUM> of the machine <NUM>. One skilled in the art would recognize that as a result of this orientation, the front wheel <NUM> turns by a turning angle with respect to the longitudinal centerline <NUM> wherein the turning angle may be greater than the desired angle by which the machine <NUM> is to be turned. For example, in the illustrated embodiment, the front wheel <NUM> is turned by a turning angle greater than <NUM> degrees (e.g., between about <NUM> degrees and about <NUM> degrees) with respect to the longitudinal centerline <NUM> of the machine <NUM> to turn the machine <NUM> away from the longitudinal centerline in the direction <NUM> shown in <FIG>. Moreover, if the front wheels <NUM>, <NUM> are to be spaced further apart than by the distance <NUM> shown in <FIG>, the turning angle of the steering wheel <NUM> increases further from the exemplary angles (e.g., greater than about <NUM> degrees) described herein in order to turn the machine <NUM> away from the longitudinal centerline (e.g., along arrow <NUM>) by an angle of about <NUM> degrees. Similarly, the steering assembly is configured for steering the front wheel by an angle less <NUM> degrees with respect to the longitudinal centerline of the machine when turning the machine toward the longitudinal centerline (e.g., along the direction <NUM>) by an angle of about <NUM> degrees.

With continued reference to <FIG>, the triangular orientation of the front wheels <NUM>, <NUM> and the rear wheel <NUM> permits a center of gravity <NUM> of the machine <NUM> to be suitably located. For instance, a projection of the center of gravity <NUM>, in the top plan view of <FIG> is shown as being positioned substantially toward the front of the transverse centerline <NUM> and within the triangle <NUM> formed by the front and rear wheels <NUM>, <NUM>, <NUM>. As is apparent to one of ordinary skill in the art, when the projected position of the center of gravity <NUM> of the machine <NUM> lies within the triangular orientation of the front and rear wheels <NUM>, <NUM>, <NUM>, the machine <NUM> remains in stable equilibrium, and is undue instabilities during use of the machine <NUM> (e.g., braking during turning, etc.) may be reduced. Such undesirable effects may include excessive lateral acceleration due to centrifugal forces directed radially outward about the center of curvature of the turn that throws the operator outwardly while turning. In some exemplary embodiments, the machine <NUM> can be front-loaded to position its center of gravity <NUM> to the front of the transverse centerline <NUM> and within the triangle <NUM>. For example, heavier components of the machine <NUM> (e.g., scrub head, battery or other power source, motive source <NUM> such as motor) can be positioned to the front of the transverse centerline <NUM>. Such embodiments have a weight distribution wherein more of the machine <NUM>'s weight is toward its front when an operator is not standing on the operator platform <NUM> and/or when solution tanks positioned to the front of the transverse centerline <NUM> comprising clean or dirty liquids are full, thereby moving the center of gravity <NUM> to the front of the transverse centerline <NUM> of the machine <NUM>. For instance, in some such cases, the center of gravity can be within the front one-third of the machine <NUM> (e.g., one-third of the distance <NUM> shown in <FIG>) and projected to fall within the triangle <NUM> formed by the first and second front wheels <NUM>, <NUM>, and the rear wheel <NUM> when the operator is not standing on the platform <NUM>. In such cases, the position of the center of gravity can be configured to remain generally within the triangle <NUM> formed by the first and second front wheels <NUM>, <NUM> and the rear wheel <NUM> when the operator is standing on the operator platform and the machine is being operated normally. As used herein, "normal operation" can refer to any of the following: being driven on a floor surface, braked, turned, braked during a turn, when solution tanks are empty, when the operator has at least one foot on the operator platform, performing one or more maintenance operations on the surface and the like. Such embodiments can also reduce the chances of the machine <NUM> (e.g., to the rear of the transverse centerline <NUM>) having weight imbalances when an operator steps on or off from the operator platform <NUM>, and when the operator is standing on the platform <NUM>. For instance, embodiments such as those disclosed herein have reduced instabilities (e.g., tipping, one of the wheels losing contact with the surface, and the like) when the operator has one foot on the operator platform <NUM>. Additionally, the machine reduces instabilities (e.g., tipping, one of the wheels losing contact with the surface, and the like) when the operator has both their feet on the operator platform <NUM>, and when the machine turns, brakes during a turn or travels on an inclined surface.

When the weight of the machine <NUM> or the operator shifts (e.g., braking during turning or traveling on an inclined surface, etc.) by allowing the center of gravity <NUM> of the machine <NUM> to remain lower to the ground and to the front of the machine <NUM> (e.g., at position <NUM>' shown in <FIG>), turning moments (e.g., that could result in instabilities due to lateral forces overcoming gravitational forces acting on the center of gravity of the machine <NUM>) are reduced as is well-known to one of ordinary skill in the art. For example, the projected position of the center of the gravity <NUM> is positioned in close proximity to the surface <NUM> such that the center of the gravity <NUM> is no greater than the lower one-half, and more preferably one-third of the machine height when an operator is standing on the operator platform <NUM>. In some such cases, the machine is stable when the operator is turning the machine (e.g., a zero turn) and/or braking while turning. In some such cases, and referring to <FIG> and <FIG>, components of the machine <NUM> can also be arranged such that the a lower portion <NUM> of the machine <NUM> below a major center plane <NUM> of the machine <NUM> is heavier relative to an upper portion <NUM> of the machine <NUM> to above the major plane <NUM> of the machine <NUM> when an operator is standing on the operator platform <NUM>. Such embodiments lower the center of gravity <NUM> so that its projected position is further toward the surface <NUM>, and reduce the machine <NUM> and/or the operator from experiencing dynamic instabilities during normal use of the machine <NUM> which can involve operations such as braking during turning, performing a zero turn, or other similar operations. During such operations, even if the weight of the machine <NUM> or the operator's position shifts, the projected position of the center of gravity <NUM> lies proximal to the surface <NUM> and within the lateral confines (e.g., sides <NUM>, <NUM>) of the triangular configuration of the front and rear wheels <NUM>, <NUM>, <NUM>. Such embodiments reduce the potential for the machine <NUM> to become unstable during routine use of the machine <NUM>.

With continued reference to <FIG> and referring now to <FIG>, the stability of the machine during turning (e.g., zero turns) or braking during turning can be illustrated by the geometric orientation of the front and rear wheels. As seen in <FIG>, the rear wheel <NUM> is cylindrical in shape and has a first lateral side <NUM> and a second lateral side <NUM>. The front wheels <NUM>, <NUM> are each oriented such that the sides <NUM>, <NUM> from each of the front wheels <NUM>, <NUM> abut the lateral sides <NUM>, <NUM> of the rear wheel <NUM>. In such embodiments, the projected position of the center of gravity <NUM> is generally contained within the triangular area between the front and rear wheels <NUM>, <NUM>, <NUM> due to front loading the machine <NUM>. As a result, force and moment imbalances are reduced, thereby allowing the operator to ride, turn, brake during turn or travel over an inclined surface with increased safety.

Continuing with the above, the center of gravity <NUM> is positioned substantially toward the front of the transverse centerline <NUM> and projected to fall within the triangle <NUM> formed by the front wheels <NUM>, <NUM> and the rear wheel <NUM> when the operator is standing on the operator platform <NUM> and performs at least one of turning, braking during a turn, or travel over an inclined surface. As shown by the schematic of <FIG>, if for instance, an operator turns the machine and/or brakes during a turn, in an exemplary embodiment, the resulting braking force vector indicated by arrow <NUM>'is toward one of the front wheels when turning.

In conventional three-wheeled machines, a single front wheel <NUM> and two rear wheels <NUM>, <NUM> form a triangle <NUM>, where the conventional three-wheeled machine has a longitudinal centerline <NUM> and a transverse centerline <NUM> as shown in <FIG>. In this embodiment, when an operator brakes during a turn, the location of the center of gravity <NUM> is inherently connected to the stable operation of the machine. For instance, if an operator turns the machine and/or brakes during a turn, the resulting braking force vector indicated by arrow <NUM>'is toward the line between the front wheel and one of the rear wheels when turning and outside the triangle <NUM>. In contrast, in embodiments of the surface maintenance machine with two front wheels and a single rear wheel illustrated schematically by <FIG>, the resulting braking force vector <NUM>' remains generally within the triangle <NUM>, and as result, has relatively improved stability while braking during a turn, ramp climbing or during a zero turn. During these operations of the machine, the machine generally resists various accelerations and decelerations better because of front wheels <NUM>, <NUM> being wide set and have a substantially broad envelope to the front of the transverse centerline <NUM> due to two front wheels <NUM>, <NUM> and a single rear wheel <NUM>. Accordingly, if the machine's normal operations such as turning, braking during a turn remains generally within the triangle <NUM>. The machine therefore has generally improved stability and resists a wheel (e.g., a front wheel inner relative to the radius of a turn) losing its contact with surface on which the machine operates due to moments about the center of gravity <NUM>.

Referring now to <FIG>, the surface maintenance machine <NUM> comprises an operator platform <NUM> to allow an operator to stand thereon. The operator platform <NUM> can be positioned to the rear of the transverse centerline <NUM> of the machine <NUM>. The operator platform <NUM> extends around the rear wheel <NUM>, and laterally outwardly from the longitudinal centerline <NUM> for supporting an operator in a standing position with the operator's legs on either side of the rear wheel <NUM> as shown in <FIG>. The rear wheel <NUM> can be positioned centrally with respect to the platform. In some such cases, the platform <NUM> optionally includes a cut-out portion <NUM>. The cut-out portion <NUM> of the operator platform <NUM> receives the rear wheel <NUM>. The operator platform <NUM> comprises a first side portion <NUM>, a second side portion <NUM> and a central portion <NUM>. The cut-out portion <NUM> in such cases is surrounded on opposite lateral sides by the first and second side portions <NUM> and <NUM>. The first and second side portions <NUM> and <NUM> are each integrally formed with the central portion <NUM>. As seen in <FIG>, the first and second side portions <NUM>, <NUM> extend on opposite sides of the rear wheel <NUM>. An operator can stand in a standing position such that the first and second side portions <NUM>, <NUM> each receive an operator's foot. Accordingly, the first and second side portions <NUM>, <NUM> can have a width sufficient to accommodate an operator's foot, <NUM>, <NUM>. For example, the width can be between about <NUM> inches (<NUM>,<NUM>) and about <NUM> inches (between about <NUM> and about <NUM>) such that an adult operator can comfortably stand in the first and second side portions <NUM>, <NUM> so that the operator's foot <NUM>, <NUM> are on both sides of the rotational axis <NUM> (and positioned thereabove). Alternatively, the operator platform <NUM> may not have a cut-out portion, and can be positioned above the rear wheel <NUM>.

Optionally, in some embodiments wherein the operator platform <NUM> has a cut-out portion <NUM>, a cover (not shown) can be positioned over the rear wheel <NUM> to avoid the operator's foot from inadvertently contacting the rear wheel <NUM>. The rear wheel <NUM> is approximately at the same height above the surface <NUM> as a central rotational axis of the rear wheel <NUM>. Such embodiments allow the operator a wider tread surface than is conventionally used in "micro" rider style surface maintenance machine <NUM> by having the rear wheel <NUM> be positioned centrally, and by having the operator platform <NUM> extend around it. In some such cases, the operator platform <NUM> is of a width <NUM> that approximately equals the width <NUM> of the maintenance path <NUM> and/or the width <NUM> of the machine.

In embodiments illustrated in <FIG>, during a turn (e.g., a zero turn), the point about which the machine turns (referred to as "center of turn") can generally be within an envelope of the operator platform when the machine is being turned up to and during a zero turn. Such embodiments allow the operator comfort during a turn and further ensure stability during zero turns.

<FIG> illustrates a side perspective view of a cross-section taken along the plane <NUM>-<NUM> illustrated in <FIG>. <FIG> illustrates a top view of a rear portion of the machine <NUM>. In <FIG> and <FIG>, the forward direction of travel of the machine <NUM> is illustrated by the arrow referenced as <NUM>. As shown in <FIG> and <FIG>, machine <NUM> has at least one rear wheel <NUM>. In embodiments where the rear wheel <NUM> is rotatable, the rotation is about the rotational axis <NUM>. As seen in <FIG> and <FIG>, the operator platform <NUM> extends both to the front and the rear of the rotational axis <NUM> of the rear wheel <NUM>. The central portion <NUM> is to the rear of the rotational axis <NUM> and the first and second side portions <NUM>, <NUM> extend to the front and rear of the rotational axis <NUM>. In such embodiments, when an operator stands on the operator platform <NUM>, the operator's feet <NUM>, <NUM> can be to the front and rear of the rotational axis <NUM>. As is seen in <FIG> and <FIG>, the operator platform <NUM> also extends to the front and rear of the entire rear wheel <NUM>. The rear wheel <NUM> is surrounded by the first and second side portions <NUM>, <NUM> and the central portion <NUM> of the operator platform <NUM>. The rear wheel <NUM> can thus be positioned, such that the operator platform <NUM> extends deeper relative to the diameter of the rear wheel <NUM>.

Embodiments of a surface maintenance machine <NUM> with a rear operator platform <NUM> disclosed herein offer several advantages. The rear standing platform allows the operator to standing in a desired position with a wider tread surface than is conventional. The rear standing platform with a wider tread allows the operator to step on and off the machine <NUM>. Components of the machine <NUM> according some embodiments are arranged to have the machine <NUM> be front loaded and the center of gravity <NUM> be lower toward the ground. Such embodiments offer improved stability, and additionally provide for efficient use of space for packaging batteries and cleaning components. Embodiments also provide for a short overall length for the machine <NUM>, forward protection for the operator, low step-on height, and easy presentation of controls to the operator. Embodiments of the machine also allows an operator to rapidly decelerate during a turn, thereby providing a safe operation of the machine (e.g., if an operator encounters an obstacle) and results in satisfactory maintenance performance (e.g., by reducing the chances of scrubbing tools from throwing off liquids when turning too fast).

Referring now to <FIG>, which illustrates a portion of the machine <NUM> shown in <FIG>, the surface maintenance machine <NUM> includes a maintenance head assembly <NUM>. The maintenance head assembly <NUM> houses one or more maintenance tools <NUM> such as scrub brushes, sweeping brushes, and polishing, stripping or burnishing pads, and tools for extracting (e.g., dry or wet vacuum tools) as described previously. The maintenance head assembly <NUM> comprises a deck <NUM> that houses one or more maintenance tools <NUM> (best seen in <FIG>). The maintenance tool <NUM> can be rotatable relative to the remainder of the maintenance head assembly <NUM> (such as the deck <NUM>), for instance, by a motive source <NUM> (e.g., a motor) that can be coupled to the maintenance tool <NUM> (e.g., using belts, or other motive force transmission systems, not shown) that apply torque and thereby impart a rotational motion on to the maintenance tools <NUM>. The maintenance head assembly <NUM> can be attached to the body (e.g., a frame member <NUM>) of the surface maintenance machine <NUM> such that the maintenance head assembly <NUM> can be lowered to an operating position (so as to be in contact with the floor surface <NUM>) and raised to a traveling position when the machine <NUM> is not performing a maintenance operation. The maintenance head assembly <NUM> is connected to the surface maintenance machine <NUM> using any known mechanism, such as a lift mechanism and suspension <NUM>, as illustrated in <CIT>.

With continued reference to <FIG>, the lift mechanism and suspension <NUM> allows the maintenance head assembly <NUM> to be raised and lowered and allows the maintenance tools <NUM> to conform to undulations in the floor. The deck <NUM> of the maintenance head assembly <NUM> is attached to the frame <NUM> of the machine <NUM> (not shown in <FIG>) by a lift mechanism and suspension <NUM> assembly that includes a lift arm <NUM>, a linear actuator (not shown), and associated coupling structures. Coupling structures include brackets, springs, control arms, and the like for providing controlled pivoting of the linear actuator relative to the deck <NUM> so as to remain in contact with the floor surface <NUM> (e.g., when traveling over uneven floor surfaces) when performing a maintenance operation, and be raised to the traveling position when the machine <NUM> is not performing a maintenance operation.

Components of the lift mechanism and suspension <NUM> can be operatively coupled to the operator console <NUM> and/or foot pedals <NUM> on the operator platform <NUM>. For example, the foot pedals <NUM> can be mechanically coupled to coupling structures of the lift mechanism and suspension <NUM>. Additionally, the foot pedals <NUM> can be electrically coupled to a controller in communication with the linear actuator such that when the foot pedals <NUM> are pressed by the operator's feet, the controller communicates with the linear actuator to raise or lower the maintenance bead assembly to move it between the operating position and the transport position.

With continued reference to <FIG>, a squeegee assembly <NUM> is provided on the rear of and connected to the maintenance head assembly <NUM>. The squeegee assembly <NUM> can drag on the surface along the sides of maintenance tool <NUM> to keep water on the floor from spreading out sidewise away from the machine <NUM>. The squeegee assembly <NUM> curves inward to direct the water centrally to the machine <NUM> toward the rear thereof. A vacuum system (not shown) is fluidly coupled to the squeegee assembly <NUM> so as to collect the water accumulating on the rear of the machine and deposit the collected water into a waste recovery tank (not shown). The maintenance head assembly <NUM> can be configured to "float" relative to machine <NUM>, thereby keeping the maintenance tool <NUM> (e.g., a brush or a pad) in contact with the surface being maintained (e.g., cleaned or treated) even if the surface is somewhat irregular or uneven. Likewise, due to the mechanical connection between the squeegee assembly <NUM> and the maintenance head assembly <NUM>, the squeegee assembly <NUM> can also float relative to machine <NUM> to enable the squeegee assembly <NUM> to remain in contact with surfaces being maintained, even though they are somewhat irregular or uneven.

The squeegee assembly <NUM> includes a frame <NUM>, squeegee blades <NUM>, <NUM>, and a retainer <NUM>. Blades may include one or more flexible blades that may be spaced apart or tight against each other. For instance, the illustrated embodiment provides an inner squeegee blade <NUM> facing the maintenance head assembly <NUM>, and an outer squeegee blade <NUM> positioned to the rear of the inner squeegee blade <NUM> (e.g., when the machine is moving in a generally forward direction). The inner squeegee blade <NUM> generally confronts water on the floor surface <NUM> first and directs water toward a central portion of the squeegee blades <NUM>, <NUM>. Further, the inner squeegee blade <NUM> and outer squeegee blade <NUM> may be in contact with the floor surface <NUM>. In some such cases, the inner squeegee blade <NUM> can have vents to draw-in liquids into a plenum formed by the inner squeegee blade <NUM> and outer squeegee blade <NUM>. The squeegee blades <NUM>, <NUM> can therefore form a seal with the floor. The vacuum system may apply a vacuum in the plenum between the outer and inner squeegee blades <NUM>, <NUM>, which, due to the seal formed with the floor surface <NUM>, and optionally due to vents on the inner squeegee blade <NUM>, facilitates suction of collected water from the center of the squeegee. Squeegee blades <NUM>, <NUM> can also deflect in a controlled manner to a predetermined extent (for instance, deflection about twice the thickness of the blade) to effectively collect liquids from the floor surface.

The blades can contact the floor surface <NUM> and are made from suitable material such as rubber, neoprene, urethane, or the like. The one or more flexible blades may be of the same or of differing thicknesses, have differing levels of flexibility, and may have differing lower extents. Exemplary squeegee assemblies contemplated in the present disclosure include the squeegee assemblies described in <CIT>, assigned to the assignee of the present application. The squeegee assembly <NUM> can be of a sufficient weight so as to apply uniform pressure on the squeegee blades <NUM>, <NUM> substantially around the perimeter of the squeegee assembly <NUM>. For instance, the weight of the squeegee assembly <NUM> can be configured so as to apply a certain magnitude of downforce on the squeegee blades <NUM>, <NUM>. Additional mechanical members (e.g., wheels and castors, as will be described further below) can further facilitate uniform application of downforce on the squeegee assembly <NUM>.

As described further below, embodiments of the present disclosure permit an interchangeable squeegee assembly <NUM> that can be connected to different sizes of maintenance tools <NUM> (brushes or pads), while facilitating easy removal for servicing (e.g., replacing or "rotating" squeegee blades <NUM>, <NUM> due to wear). Further, the squeegee assembly <NUM> according to certain embodiments of the present disclosure can also be designed as articulating, so as to effectively direct and collect water from the surface when the machine is being turned (e.g., around a corner in a building).

<FIG> is a top plan view of the assembly shown in <FIG> to illustrate the relative position of the squeegee assembly <NUM> and the maintenance head assembly <NUM> when the machine is traveling in a generally straight path in a direction indicated by the arrow. <FIG> show respectively, a perspective view and a top plan view of the squeegee assembly <NUM> of <FIG> to illustrate the relative position of the squeegee assembly <NUM> and the maintenance head assembly <NUM> when the machine takes a turn relative to the direction <NUM>. As seen in <FIG>, some embodiments of the present disclosure advantageously provide an articulating mechanism <NUM> to permit controlled articulation of the squeegee assembly <NUM> when the machine is turned (e.g., a right or a left turn, relative to the travel direction shown in <FIG>) to direct and collect water that may pool up when the machine is turned.

Referring now to <FIG>, the articulating mechanism <NUM> is attached to coupling structures on the deck <NUM> of the maintenance head assembly <NUM>. For example, the articulating mechanism <NUM> can be connected to brackets <NUM> to which the lift arm <NUM> of the lift mechanism and suspension <NUM>. Of course, the articulating mechanism <NUM> can also be connected at other locations on the deck <NUM> of the maintenance head assembly <NUM>. The connection of the articulating mechanism <NUM> can be such that it is easily removable in the event that the squeegee assembly <NUM> needs to be replaced for servicing. For instance, the connection of the articulating mechanism <NUM> can be to the exterior of the motive source <NUM> (e.g., motor) of the maintenance head assembly <NUM>, so that an operator may be able to detach the squeegee assembly <NUM> without having to disconnect numerous connections such as those of the lift mechanism and suspension <NUM>, and the like.

As seen in <FIG>, the articulating mechanism <NUM> permits controlled articulation of the squeegee assembly <NUM>. As used herein, the term articulation may include both pivotal motion (along arrows <NUM>) of the squeegee assembly <NUM> relative to the maintenance head assembly <NUM> about a pivot axis <NUM>, as well as swivel motion (along arrows <NUM>) of the squeegee assembly <NUM> about the swivel axis <NUM>. In some exemplary embodiments, the articulating mechanism <NUM> may permit a swivel of about <NUM> degrees either side of the swivel axis <NUM>, thereby a total swivel arc of about <NUM> degrees. Such embodiments permit effectively collecting water from behind the machine when the machine completes a sharp turn of about <NUM> degrees. In such cases, as is apparent to one skilled in the art, the swivel axis <NUM> of the squeegee assembly <NUM> generally coincides with the center of turn of the machine and/or centroid of the maintenance head assembly <NUM>.

<FIG> illustrate another embodiment of the maintenance head assembly <NUM>. The maintenance head assembly <NUM> of <FIG> are substantially similar to that illustrated in <FIG>, with the exception that the embodiment of <FIG> is generally oval in shape (as seen from the top plan view of <FIG>), with a deck <NUM> configured to house a pair of disc-shaped maintenance tools (e.g., brushes or pads), whereas the embodiment of <FIG> is generally circular in shape (as seen from the top plan view of <FIG>). In the view shown in <FIG>, the machine is traveling in a generally straight path, in a direction indicated by the arrow <NUM>. <FIG> show respectively, a perspective view and a top plan view of the maintenance head assembly <NUM> of <FIG> to illustrate the relative position of the squeegee assembly <NUM> and the maintenance head assembly <NUM> when the machine takes a turn. While the articulating mechanism <NUM> is described above with respect to <FIG>, it should be understood that the articulating mechanism <NUM> shown in <FIG> operates in a similar fashion to that shown in <FIG>.

<FIG> illustrates an enlarged perspective view of the articulating mechanism <NUM>. The articulating mechanism <NUM> seen in <FIG> can be coupled to the maintenance head assembly <NUM> shown in <FIG> or maintenance head assembly <NUM> shown in <FIG>. As seen therein, the articulating mechanism <NUM> comprises a swivel mechanism <NUM> for controlled swivel of the squeegee assembly <NUM> about the swivel axis <NUM> and a hinge mechanism <NUM> for controlled pivoting of the squeegee assembly <NUM> about the pivot axis. The swivel mechanism <NUM> comprises at least one curved rail on which two or more rollers <NUM>, <NUM> are guided. In the illustrated embodiment, two curved rails <NUM>, <NUM> radially offset from each other. The rails <NUM>, <NUM> are curved such that they have a center of curvature that coincides with the swivel axis <NUM>, and in turn, the center of turn of the machine and/or centroid of the maintenance head assembly <NUM>. In the illustrated embodiment, the curvature of the rails <NUM>, <NUM> corresponds to an arc extending between about <NUM> degrees and about <NUM> degrees. Further, the curvature of the rails <NUM>, <NUM> is generally circular (e.g., as seen from the top view of <FIG>, <FIG>, <FIG> and <FIG>) such that any two points on the rails <NUM>, <NUM> are generally equidistant from the center of the curvature of the rails <NUM>, <NUM> (as is apparent from <FIG>). While two rails having a fixed radius corresponding to a circular shape is illustrated, other shapes of the rails <NUM>, <NUM> (e.g., a non-circular curvature) can be used to customize the articulating mechanism based on the machine architecture. For example, the rails <NUM>, <NUM> can follow a generally oval shape when viewed from the top so as to conform to the shape of the oval maintenance head assembly shown in <FIG>. Alternatively, a non-uniform shape can also be used for other machine and/or maintenance head assembly architectures.

While the rails <NUM>, <NUM> are illustrated as being generally tubular in shape, other shapes such as rectangular or square cross-section are contemplated within the scope of the present disclosure. Further, in addition to being radially offset, the rails <NUM>, <NUM> can be axially offset (e.g., along the swivel axis <NUM>) such that one rail is above another rail. Alternatively, the rails <NUM>, <NUM> may not be radially offset, but may be axially offset such that one rail is above another rail, but both rails have the same radius from their center of curvature. Any orientation of the rails <NUM>, <NUM> that is adequately rigid and resists structural loads (e.g., flexures) generated due to swiveling of the squeegee assembly <NUM> when the machine turns, and supports the weight of the squeegee assembly <NUM> can be used. Additionally, while rails are illustrated, it should be noted that track and carriage systems or other mechanical equivalents that permit guided motion of the squeegee assembly <NUM> over an arcuate path are contemplated within the scope of the present disclosure.

With continued reference to <FIG>, the swivel mechanism <NUM> comprises a pair of rollers <NUM>, <NUM> housed in a swivel bracket <NUM> that roll against the rails <NUM>, <NUM>. The rollers <NUM>, <NUM> and rails <NUM>, <NUM> can be configured to have minimal friction therebetween such that the rollers <NUM>, <NUM> freely roll in a guided fashion along the rails <NUM>, <NUM>. For instance, and referring now to the sectional view of <FIG>, the rollers <NUM>, <NUM> comprise an outer sleeve <NUM> made of low-friction materials such as Delrin, nylon, and the like permitting frictionless rolling motion of the outer sleeve <NUM> on at least one rail (for instance, the inner rail <NUM>). Additionally, the rollers <NUM>, <NUM> can also roll on the outer rail <NUM>. Further, the rollers <NUM>, <NUM> comprise a metal bushing <NUM> housed within the outer sleeve <NUM> so that the rollers <NUM>, <NUM> can maintain structural rigidity and withstand dynamic loads experienced while rolling on the rails. For example, while the outer sleeve <NUM> may roll against at least one of the rails <NUM>, <NUM> when the machine turns, the bushing <NUM> may be substantially stationary relative to the outer sleeve <NUM> so as to support and balance the articulating motion of the squeegee assembly <NUM> and associated loads acting thereon. The outer sleeve <NUM> of the rollers <NUM>, <NUM> can have end caps that engage with at least one of the rails <NUM>, <NUM>, and to reduce the chances of the rollers <NUM>, <NUM> separating from the rails <NUM>, <NUM>. In the illustrated embodiment, the rollers <NUM>, <NUM> are shaped to resemble spools, although any shape that provides the above-described function is contemplated within the scope of the present disclosure.

Referring back to <FIG>, the rollers <NUM>, <NUM> are connected to the swivel bracket <NUM> by way of a bolted connection. When connected, the rollers <NUM>, <NUM> are spaced apart from each other along a circumferential direction by an arc distance. In the illustrated embodiment, the spacing between the two rollers <NUM>, <NUM> extends an arc of between about <NUM> degrees and about <NUM> degrees. Such embodiments provide sufficient resistance to certain forces by spreading out such forces acting on the swivel mechanism <NUM> over a larger area. For instance, if the squeegee assembly <NUM> abuts against an obstacle and experiences side impact when the squeegee assembly <NUM> has swiveled to the position shown in <FIG> or <FIG>, the side impact experienced by the squeegee assembly <NUM> is spread out over a substantial area of the swivel bracket <NUM>, thereby reducing damage to the swivel mechanism <NUM>. As is apparent to one skilled in the art, further spacing the rollers <NUM>, <NUM> apart may provide additional area to distribute impact loads, however, at the expense of reduced swivel path. While the examples illustrated herein permit a swivel of about <NUM> degrees on either side of the swivel axis <NUM> (for a total of about <NUM> degrees), larger or smaller swivel is contemplated within the scope of the present disclosure. For example, the swivel can be between about <NUM> degrees and about <NUM> degrees. Similarly, roller spacing greater than or less than those illustrated (e.g., between about <NUM> degrees and about <NUM> degrees) are contemplated within the scope of the present disclosure.

Referring back to <FIG>, as alluded to before, the rails <NUM>, <NUM> are connected to the maintenance head assembly <NUM> by way of brackets <NUM> and a bolted connection. Advantageously, the brackets <NUM> connect to the brackets of the lift mechanism and suspension <NUM> which provides a compact connection of the squeegee assembly <NUM> to the maintenance head assembly <NUM>. The brackets, while illustrated as L-shaped, can be of any shape so as to serve as limit stops for the swivel mechanism <NUM> to reduce the chances of the squeegee assembly <NUM> traveling too far, and being damaged (e.g., by making contact with wheels <NUM> of the machine). In the illustrated embodiment, the brackets are positioned diametrically opposite to each other (e.g., about <NUM> degrees apart) accommodate a swivel arc of between about <NUM> degrees about <NUM> degrees, though of course, the brackets <NUM> may be positioned closer or farther apart.

Referring again to <FIG>, the articulating mechanism <NUM> comprises a hinge mechanism <NUM> for controlled pivoting of the squeegee assembly <NUM> relative to the maintenance head assembly <NUM> about one or more pivot axes. The hinge mechanism <NUM> facilitates maintaining the squeegee assembly <NUM> (e.g., squeegee blades <NUM>, <NUM>) generally parallel to the floor. The hinge mechanism <NUM> permits the squeegee blades <NUM>, <NUM> (e.g., the outer squeegee blade <NUM>) to remain in contact with the floor surface <NUM>. The hinge mechanism <NUM> is a double-hinge design, permitting pivoting of the squeegee assembly <NUM> relative to the maintenance head assembly <NUM> about a first pivot axis <NUM>, and a second pivot axis <NUM>. The first pivot axis <NUM> offset vertically above the second pivot axis <NUM>. The hinge mechanism <NUM> comprises a hinge plate <NUM> that engages with the swivel bracket <NUM> at one end, and an H-shaped hinge bracket <NUM> at the other end. The first pivot axis <NUM> passes through the hinge plate <NUM>. The hinge bracket, in turn is connected with vertical brackets <NUM> by a bolted connection. The second hinge axis passes through the bolted connection between the hinge bracket and the vertical brackets <NUM>.

Such a configuration may permit the squeegee to be in contact with the floor surface <NUM> in different modes. For instance, the machine may be operated when the squeegee picks up water from floor while the maintenance tool <NUM> (e.g., scrub brush) is in contact with the floor surface <NUM> and is performing a maintenance operation (e.g., scrubbing). Alternatively, the machine may be operated such that the squeegee picks up water from the floor while the maintenance tool <NUM> is not in contact with the floor surface <NUM>, for instance, when excess water from a flooding may have to be picked up from the ground. Still further, the squeegee may have to not be in contact with the floor surface <NUM> while the maintenance tool <NUM> is performing a maintenance operation (e.g., a pre-soak while scrubbing). In such cases, the double hinge design of the hinge mechanism <NUM> allows the squeegee assembly <NUM> to be raised above or below the maintenance head assembly <NUM>, while also permitting the squeegee blades <NUM>, <NUM> to be parallel to the floor surface <NUM>. Such embodiments advantageously offer effective water pick-up which may not be possible with hinge mechanism <NUM> that permit pivoting about a single pivot axis. Instead of the illustrated hinge mechanism <NUM>, mechanical equivalents, such as a vertically-oriented slot and/or rollers housed within the vertical slot can also be used in alternative embodiments.

<FIG> illustrates a side view of the squeegee assembly <NUM> of the present embodiment. As mentioned above, the embodiment illustrated in <FIG> can be used interchangeably with the maintenance head assembly <NUM> shown in <FIG> or <FIG>. The squeegee assembly <NUM> comprises a first set of end wheels. In the illustrated embodiment, the squeegee assembly <NUM> comprises four end wheels. A first end wheel <NUM> is configured to roll on the surface <NUM> when the squeegee assembly <NUM> articulates (e.g., into the positions shown in <FIG>, <FIG>) when the machine turns. Further, a second end wheel <NUM> provided with a rotational axis <NUM> perpendicular to the rotational axis <NUM> of the first end wheel <NUM>. Further, the first end wheel <NUM> may swivel about the plane containing the rotational axis <NUM>, for instance, relative to the maintenance head assembly as illustrated in <FIG>. As is apparent to one skilled in the art, the squeegee assembly <NUM> comprises a second set of end wheels opposite to the first set of end wheels so that the first and second set of end wheels terminate at the opposite ends of the curved squeegee assembly <NUM>. Similar to the first set of end wheels, the second set of end wheels may comprise a third end wheel <NUM> configured to roll on the surface <NUM> when the squeegee assembly <NUM> articulates (e.g., into the positions shown in <FIG>, <FIG>) when the machine turns. Further, a fourth end wheel <NUM> provided with a rotational axis perpendicular to the rotational axis of the third end wheel <NUM>. While end wheels are illustrated as cylindrical members that can swivel, it should be understood that castors may also be used in lieu of end wheels without loss of functionality. In the illustrated embodiment, end wheel <NUM> may act as a bumper when the squeegee assembly encounters lateral impacts due to an obstruction (e.g., a wall), whereas the end wheel <NUM> can support the front of the squeegee assembly during transport. Instead of wheels <NUM> and/or <NUM>, as is apparent to one skilled in the art, other mechanical means that act as bumpers and/or supports (e.g., simple brackets) may be used without loss of functionality.

In addition to the set of end wheels, as is seen from <FIG>, the squeegee assembly <NUM> includes a caster <NUM> positioned centrally between the first and second set of end wheels. As indicated previously, the mass of the squeegee assembly <NUM> facilitates applying a predetermined magnitude of downforce on the squeegee blades <NUM>, <NUM>. The end wheels (e.g., first end wheel and third end wheel <NUM>) and caster <NUM> can further facilitate uniform application of downforce on the squeegee assembly <NUM>.

The caster <NUM> and/or end wheels may also facilitate articulating the squeegee assembly <NUM> corresponding to the direction of turn of the machine. For instance, when the machine turns in a certain predefined direction (e.g., a <NUM>-degree right turn relative to its forward direction of motion), as a result of the frictional contact of the squeegee blades <NUM>, <NUM> on the floor surface <NUM> and the squeegee assembly <NUM> may articulate to follow the direction of turn of the machine, while collecting water from rearward of the machine. For example, to collect water as the machine turns, the squeegee may articulate in a direction opposite to the direction of turn of the machine (e.g., as a result of frictional contact of the squeegee blades <NUM>, <NUM> with the floor surface). Thus, if the machine makes a <NUM> degree turn relative to the forward direction, the squeegee assembly <NUM> may move leftward relative to the forward direction. Such a motion of the squeegee assembly <NUM> may be cooperatively accomplished by the uniform downforce acting on the squeegee blades <NUM>, <NUM>, and/or vacuum between the squeegee blades <NUM>, <NUM>, which acts to keep the squeegee blades <NUM>, <NUM> pressed against the floor surface <NUM> while the machine turns, and/or the motion of the caster <NUM> and/or end wheels.

Embodiments of the present disclosure provide an interchangeable squeegee assembly that can articulate when the machine turns to effectively pick up water during wet maintenance operations such as scrubbing. The articulating mechanism according to the present disclosure may be interchangeably used with maintenance tools (e.g., scrub brushes) of different size, and may attach to exterior components of maintenance head assemblies to permit easy removal for servicing and/or replacement.

<FIG> illustrate portions of the surface maintenance machine with several of the external body panels not shown in <FIG>. As illustrated, the body panels, when added, define a storage area for storing a variety of tools and supplies <NUM> as will be described further below. With reference to <FIG>, the mobile body of the surface maintenance machine includes a forward section <NUM>, a middle section <NUM> and a rearward section <NUM>. The terms "forward", "rearward" and "middle section <NUM>" are referenced with respect to the direction of travel <NUM> of the machine and the transverse centerline <NUM> of the machine. For instance, as illustrated, the forward section <NUM> is positioned to the front of the transverse centerline <NUM> of the machine, the middle section <NUM> is generally centered on the transverse centerline <NUM> and the rearward section <NUM> is positioned to the rear of the transverse centerline <NUM>, when the machine moves in the direction <NUM>.

With continued reference to <FIG>, and referring now to <FIG>, the forward section <NUM> extends over a forward section depth 700d, the middle section <NUM> extends over a middle section depth 702d, and the rearward section <NUM> extends over a rearward section depth 704d. As is apparent, each of the forward section depth 700d, the middle section depth 702d, and the rearward section depth 704d can be defined in a direction parallel to the direction of travel <NUM> of the machine. Further, the forward section <NUM> can extend over a forward section width 700w, the middle section <NUM> extends over a middle section width 702w, and the rearward section <NUM> extends over a rearward section width 704w. In this case, each of the forward section width 700w, middle section width 702w and the rearward section width 704w can be defined in a direction perpendicular to the direction of travel <NUM> and/or between lateral walls <NUM>, <NUM> of the machine.

The machine can have overall dimensions configured such that at least two of the forward section depth 700d, the middle section depth 702d, and the rearward section depth 704d are equal. Further, at least two of the forward section width 700w, the middle section width 702w, and the rearward section width 704w can be equal. In some examples, the forward section <NUM> and the rearward section <NUM> can have generally equal dimensions. Further, the forward section <NUM>, the middle section <NUM> and the rearward section <NUM> can all be substantially of the same dimensions.

With reference to <FIG> and referring now to <FIG>, body panels of the machine may define the boundaries of the storage area so as to isolate it from various components of the machine such as batteries <NUM>, solution and/or recovery tanks, sweep chamber and/or hopper, maintenance tools, and the like. For instance, the body may have a center plane <NUM> parallel to the floor surface and a generally planar top surface <NUM> positioned above the center plane <NUM> of the body and generally parallel thereto. The generally planar top surface <NUM> can be at a first distance <NUM> above the floor surface. Further, the body can have a generally planar lower surface <NUM> positioned below the center plane <NUM> of the body and generally parallel thereto. The generally planar lower surface <NUM> can be located at a second distance <NUM> below the generally planar top surface <NUM>.

With continued reference to <FIG> and <FIG>, the body panels may further include boundaries that define a storage chamber <NUM>. For instance, the body panels may include a front wall <NUM>, a rear wall <NUM>, lateral walls <NUM>, <NUM>, such that the storage chamber <NUM> is generally isolated from components of the surface maintenance machine and generally hollow to permit storage of maintenance tools and/or supplies <NUM>. As mentioned previously, "front", "rear" and "lateral" refer to the position and orientation with respect to the direction of travel <NUM> and/or transverse centerline <NUM>. As seen in <FIG> and <FIG>, the front wall <NUM> of the storage chamber <NUM> abuts the forward section <NUM> and the rear wall <NUM> of the storage chamber <NUM> abuts the rearward section <NUM>. For instance, the front wall <NUM> can be a common boundary between the forward section <NUM> and the middle section <NUM>. Likewise, the rear wall <NUM> can be a common boundary between the middle section <NUM> and rearward section <NUM>. As seen in <FIG> and <FIG>, the storage chamber <NUM> extends over a depth 730d (defined between its lateral walls <NUM>, <NUM>) substantially equal to the middle section depth 702d and over a width 730w substantially equal to the middle section width 702w.

Referring back to <FIG>, the generally planar top surface <NUM> can be located at a first distance <NUM> from the floor surface whereby, the first distance <NUM> corresponds to the machine height. In such cases, the storage chamber <NUM> can extend between the generally planar top surface <NUM> and the generally planar lower surface <NUM> of the machine body wherein the generally planar lower surface <NUM> is at a second distance <NUM> below the generally planar top surface <NUM>, such that the second distance <NUM> generally corresponds to the height of the storage chamber <NUM>. In some such cases, the second distance <NUM> is greater than about two-thirds of the first distance <NUM>. In such cases, the storage chamber <NUM> may extend over a height of about two-thirds the height of the machine.

Referring again to <FIG>, the boundaries of the storage chamber <NUM> facilitate substantially isolating the storage chamber <NUM> from components of the machine. For instance, the storage chamber <NUM> can be fluidly isolated from a maintenance chamber <NUM> that houses one or more maintenance tools. Further, as seen in <FIG>, components of the machine can be re-arranged so as to permit a substantially hollow middle section <NUM> for defining the storage chamber <NUM>. For instance, components of the machine such as batteries <NUM> for propelling the machine, and/or recovery tank <NUM> for collecting fluids from the floor surface, can be substantially located in the forward section <NUM>. Further, solution tank for supplying a fluid toward a floor surface may be positioned outside the middle section <NUM>. In the illustrated embodiment, for instance, the solution tank is defined peripherally around the body of the vehicle, with an inlet port <NUM> positioned in the rearward section <NUM>.

With continued reference to <FIG>, and as indicated above, components of the machine (e.g., such as batteries <NUM>, maintenance head assemblies, solution tanks, vacuum systems, machine controls and the like), can be arranged to create a substantially hollow portion having a volume sufficient to house the storage chamber <NUM>. As shown in <FIG>, in one example, the entirety of the batteries <NUM> and the recovery tank <NUM> can be respectively located in the forward section <NUM>, though, portions of the recovery hose <NUM> may pass around the storage chamber <NUM>. Continuing with the example illustrated in <FIG>, a storage chamber bottom surface <NUM> can be coplanar with or below a top surface <NUM> of at least one battery positioned in the forward section <NUM>. Such embodiments permit an adequate volume of storage chamber <NUM> to store a variety of maintenance tools and/or supplies <NUM>.

Referring now to <FIG>, the storage chamber <NUM> comprises one or more access doors for permitting access to the storage chamber <NUM> when opened. In the illustrated embodiment, the storage chamber <NUM> comprises a first access door <NUM> configured to open in a lateral direction <NUM>. The first access door <NUM> can be formed by at least portions of a lateral wall of the storage chamber <NUM>. Further, the first access door <NUM> (and in turn, the lateral walls <NUM>, <NUM> of the storage chamber <NUM>) can be generally coplanar with lateral walls <NUM>, <NUM> of the machine, such that the storage chamber <NUM> is generally confined within the lateral extents of the machine and does not protrude outside of the machine envelope. With continued reference to <FIG>, the storage chamber <NUM> comprises a second access door <NUM> configured to open in a direction <NUM> perpendicular to the direction of opening <NUM> of the first access door <NUM>. Additionally, either, or both of the first access door <NUM> and the second access door <NUM> may be accessible from the operator platform such that the operator may access them (e.g., grasp and/or open). As is apparent from <FIG>, the second access door <NUM> is generally coplanar with the generally planar top surface <NUM> such that the storage chamber <NUM> can remain confined within a machine envelope. In such cases, the lateral walls <NUM>, <NUM> of the machine and the generally planar top surface <NUM> may constitute at least portions of the outer boundaries of the envelope.

Referring back to <FIG>, the storage chamber <NUM> defined in the middle section <NUM> of the machine body for storing surface maintenance tools and supplies <NUM> that an operator may use for performing one or more manual surface maintenance tasks. For instance, the operator may remove the surface maintenance tools and/or supplies <NUM>, such as spray bottles housed in a caddy <NUM> with a one or more bins <NUM>, brooms and/or mops <NUM>, wash cloths, and the like and transport them manually to a location where a manual maintenance operation is to be performed. Referring now to <FIG>, the storage chamber <NUM> may also be configured to store debris collected from the manual maintenance, for instance, in a trash bag <NUM>, that may be positioned in the storage chamber <NUM> (e.g., using frame elements <NUM>).

As seen in <FIG> and referring to the enlarged portions thereof illustrated in <FIG>, the storage chamber <NUM> can be of a modular design so as to facilitate housing individual storage modules such as a storage caddy <NUM>, one or more storage bins <NUM>, a drip catching bin for storing/collecting fluids from a mop, a debris compartment and the like. For instance, in <FIG>, the storage chamber <NUM> is illustrated as having a trash bag <NUM> housed therewithin, whereby the trash bag <NUM> extends substantially over the height of the storage chamber <NUM>. <FIG> illustrates another use of the storage chamber <NUM>, whereby the trash bag <NUM> extends over one half of the height of the storage chamber <NUM>, and a storage bin is placed in the remaining space. <FIG> illustrates a further use of the storage chamber <NUM>, wherein a plurality of bins <NUM>/trays can be placed in the space within the storage chamber <NUM> instead of a trash bag <NUM>. Any such modular arrangements are contemplated within the scope of the present disclosure.

Claim 1:
A surface maintenance machine (<NUM>) comprising:
a frame (<NUM>);
a maintenance head assembly (<NUM>) supported by the machine (<NUM>) and extending toward a surface, the maintenance head assembly (<NUM>) comprising one or more surface maintenance tools for performing a surface maintenance operation;
a first front wheel (<NUM>), and a second front wheel (<NUM>), the first (<NUM>) and second (<NUM>) front wheels being positioned to the front of a transverse centerline (<NUM>) of the machine (<NUM>) when the machine (<NUM>) is moving in a forward direction, at least one of the first (<NUM>) and second (<NUM>) front wheels being steerable by a steering mechanism,
a rear wheel (<NUM>) positioned to the rear of the transverse centerline (<NUM>) of the machine (<NUM>) when the machine (<NUM>) is moving in a forward direction;
characterized in that:
a longitudinal centerline (<NUM>) of the machine (<NUM>) extends through the rear wheel (<NUM>) at a lateral center point of the rear wheel (<NUM>), the first (<NUM>) and second (<NUM>) front wheels being positioned on opposite sides of the longitudinal centerline (<NUM>), such that the first (<NUM>) and second (<NUM>) front wheels and the rear wheel (<NUM>) form a triangle, the surface maintenance machine (<NUM>) having a center of gravity; and
an operator platform (<NUM>) supported by the frame (<NUM>) and configured for allowing an operator to stand thereon, the operator platform (<NUM>) positioned to the rear of the transverse centerline (<NUM>) of the machine (<NUM>), such that the center of gravity of the machine (<NUM>) is positioned in the front one-third of the machine (<NUM>) and within the triangle formed by the first (<NUM>) and second (<NUM>) front wheels and the rear wheel (<NUM>) when the operator is not standing on the platform, the machine (<NUM>) be configured such that the position of the center of gravity remains generally within the triangle formed by the first (<NUM>) and second (<NUM>) front wheels and the rear wheel (<NUM>) when the operator is standing on the operator platform (<NUM>) and the machine (<NUM>) is being operated normally.