Adjustable rack assemblies and end caps for appliances

Adjustable rack assemblies and end caps for appliances, such as a dishwasher appliance, is provided herein. A rack assembly may include a frame, a rack, a first front wheel, a second front wheel, and an end cap. The rack may be selectively mounted to the frame to receive articles for washing within a wash chamber, and may be slidable along the frame between an extended position and a retracted position. The first front wheel may be rotatably attached to the rack above the frame. The second front wheel may be rotatably attached to the rack below the first front wheel in vertical alignment therewith. The end cap may be attached to the frame at a forward end thereof. The end cap may define a top-end catch profile and a bottom-end relief profile.

FIELD OF THE INVENTION

The present subject matter relates generally to rack assemblies for appliances, such as dishwasher appliances.

BACKGROUND OF THE INVENTION

Various appliances have slidable rack assemblies for holding articles therein. For example, a dishwasher appliance is typically provided with one or more rack assemblies into which various articles may be loaded for cleaning. The rack assemblies may include features such as, for example, tines that hold and orient the articles to receive sprays of wash and rinse fluids during the cleaning process. The articles to be cleaned may include a variety of dishes, cooking utensils, silverware, and other items.

The size of the articles can vary significantly. For example, glasses are available in a variety of different heights. Dishes are manufactured with various diameters between large and small. Pots used for cooking can have different depths.

In order to accommodate the larger articles, some dishwasher appliances include an upper rack assembly of a dishwasher appliance with features for height adjustment of the rack assembly. Such adjustability allows for movement of the upper rack assembly along a vertical direction. By moving or lifting the upper rack to a higher vertical height setting, larger articles can be accommodated in, for example, a lower rack assembly positioned beneath the upper rack assembly. Conversely, by lowering the upper rack to a lower vertical height setting, larger articles can be accommodated in, for, the upper rack assembly.

Certain adjustment features have been proposed for providing height adjustability for a rack assembly. Typically, these features include multiple moving parts that may require the user to manipulate both the rack assembly and the adjustment features at the same time when lifting or lowering the rack assembly. For example, the user may be required to lower or lift the rack assembly while simultaneously depressing or squeezing a lever or other aspect of the adjustment feature. For certain users, these adjustment features can be difficult to operate.

In some appliances, an end cap is provided at a front end of the rack assembly to prevent excessive forward movement of the assembly. For instance, the end cap may catch a wheel rolling along a top portion of the rack assembly. If the assembly is adjustable between multiple heights (i.e., vertical height settings), a different wheel may be provided at each height to be received by the end cap. However, the end cap may risk interfering with lower elements, such as the lower wheels, of the assembly (e.g., during height adjustment operations). Some existing rack assemblies stagger the wheels at each different height so that they are offset (e.g., relative the direction that rack assembly slides). This offset may prevent the end cap from hitting or interfering with the other wheels, but it limits the amount of sliding travel for the rack assembly. In other words, it limits how far the rack assembly may be pulled out from the wash chamber of a dishwasher appliance at certain heights or height settings.

Accordingly, a rack assembly for an appliance that can be easily adjusted to different vertical positions would be useful. In particular, a rack assembly for an appliance that can be easily adjusted to different vertical positions without limiting the amount of sliding travel of the rack assembly would be useful.

BRIEF DESCRIPTION OF THE INVENTION

In one exemplary aspect of the present disclosure, a rack assembly is provided. The rack assembly may include a frame, a rack, a first front wheel, a second front wheel, and an end cap. The frame may be positioned within a wash chamber of a dishwasher appliance. The rack may be selectively mounted to the frame to receive articles for washing. The rack may be slidable along the frame in a transverse direction between an extended position and a retracted position. The first front wheel may be rotatably attached to the rack above the frame. The second front wheel may be rotatably attached to the rack below the first front wheel in vertical alignment with the first front wheel. The end cap may be attached to the frame at a forward end thereof. The end cap may define a top-end catch profile and a bottom-end relief profile. The top-end catch profile may be directed rearward along the transverse direction. The top-end catch profile may have a transverse profile segment and a vertical profile segment extending from and above the transverse profile segment to receive the first front wheel in the extended position. The bottom-end relief profile may be directed forward along the transverse direction.

In another exemplary aspect of the present disclosure, a rack assembly is provided. The rack assembly may include a frame, a rack, a first front wheel, a second front wheel, and an end cap. The frame may be positioned within a wash chamber of a dishwasher appliance. The rack may be selectively mounted to the frame to receive articles for washing. The rack may be slidable along the frame in a transverse direction between an extended position and a retracted position. The first front wheel may be rotatably attached to the rack above the frame. The second front wheel may be rotatably attached to the rack below the first front wheel in vertical alignment with the first front wheel. The end cap may be attached to the frame at a forward end thereof. The end cap may define a top-end catch profile and a bottom-end relief profile. The top-end catch profile may have a transverse profile segment and a vertical profile segment extending arcuately from and above the transverse profile segment to receive the first front wheel in the extended position. The vertical profile segment may define a top vertex. The bottom-end relief profile may have a concave profile segment defining a bottom vertex and being directed forward along the transverse direction. The top vertex may be defined forward relative to the bottom vertex in the transverse direction. Moreover, at least a portion of the transverse profile segment may be defined forward relative to the bottom vertex along the transverse direction.

DETAILED DESCRIPTION

In order to aid understanding of this disclosure, several terms are defined below. The defined terms are understood to have meanings commonly recognized by persons of ordinary skill in the arts relevant to the present invention. The terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “includes” and “including” are intended to be inclusive in a manner similar to the term “comprising.” Similarly, the term “or” is generally intended to be inclusive (i.e., “A or B” is intended to mean “A or B or both”). Furthermore, as used herein, terms of approximation, such as “approximately,” “substantially,” or “about,” refer to being within a ten percent margin of error.

Turning now to the figures,FIGS. 1 and 2depict a dishwasher appliance100according to an exemplary embodiment of the present disclosure. Dishwasher appliance100defines a vertical direction V, a lateral direction L (FIG. 1), and a transverse direction T (FIG. 2). The vertical, lateral, and transverse directions V, L, and T are mutually perpendicular and form an orthogonal direction system.

Dishwasher appliance100also includes a cabinet102(or chassis) having a tub104therein that defines a wash chamber106. The tub104includes a front opening and a door120hinged at its bottom122for movement between a normally closed vertical position (shown inFIGS. 1 and 2), wherein the wash chamber106is sealed shut for washing operation, and a horizontal open position for loading and unloading of articles from dishwasher appliance100. In some embodiments, a latch114is used to lock and unlock door120for access to chamber106.

Slide assemblies124are mounted on opposing tub sidewalls128to support and provide for movement for a rack assembly (e.g., upper rack assembly130). In some embodiments, lower guides126are positioned in opposing manner of the sides of chamber106and provide a ridge or shelf for roller assemblies136so as to support and provide for movement of lower rack assembly132. Each of the upper and lower rack assemblies130,132is include a rack (e.g., rack210) fabricated into lattice structures including a plurality of elongated members134and135that extend in lateral (L), transverse (T), or vertical (V) directions. Each rack assembly130,132is adapted for movement between an extended loading position (not shown) in which the rack is substantially positioned outside the wash chamber106, and a retracted position (shown inFIGS. 1 and 2) in which the rack is located inside the wash chamber106. This is facilitated by slide assemblies124and roller assemblies136that carry rack assemblies130and132, respectively. Optionally, a silverware basket150may be removably attached to the lower rack assembly132for placement of silverware, small utensils, and the like, that are too small to be accommodated by the upper and lower racks130,132.

The dishwasher appliance100further includes a lower spray assembly144that is rotatably mounted within a lower region146of the wash chamber106and above a tub sump portion142so as to rotate in relatively close proximity to the lower rack132. A mid-level spray assembly148is located in an upper region of the wash chamber106and may be located in close proximity to upper rack130. Additionally, an upper spray assembly (not shown) may be located above the upper rack130.

The lower and mid-level spray assemblies144,148and the upper spray assembly are fed by a fluid circulation assembly for circulating water and wash fluid in the tub104. Portions of the fluid circulation assembly may be located in a machinery compartment140located below the bottom sump portion142of the tub104, as generally recognized in the art. Each spray assembly includes an arrangement of discharge ports or orifices for directing washing liquid onto dishes or other articles located in the upper and lower racks130,132, respectively. The arrangement of the discharge ports in at least the lower spray assembly144provides a rotational force by virtue of washing fluid flowing through the discharge ports. The resultant rotation of the lower spray assembly144provides coverage of dishes and other articles with a washing spray.

Dishwasher appliance100is further equipped with a controller116to regulate operation of dishwasher appliance100. Controller116may include a memory (e.g., non-transitive memory) and microprocessor, such as a general or special purpose microprocessor operable to execute programming instructions or micro-control code associated with a cleaning cycle. The memory may represent random access memory such as DRAM, or read only memory such as ROM or FLASH. In one embodiment, the processor executes programming instructions stored in memory. The memory may be a separate component from the processor or may be included onboard within the processor.

Controller116may be positioned in a variety of locations throughout dishwasher appliance100. In the illustrated embodiment, controller116may be located within a control panel area110of door120as shown. In such an embodiment, input/output (“I/O”) signals may be routed between the control system and various operational components of dishwasher appliance100along wiring harnesses that may be routed through bottom122of door120. In certain embodiments, the controller116includes a user interface panel112through which a user may select various operational features and modes and monitor progress of the dishwasher appliance100. In one embodiment, user interface panel112may represent a general purpose I/O (“GPIO”) device or functional block. In one embodiment, the user interface panel112may include input components, such as one or more of a variety of electrical, mechanical or electro-mechanical input devices including rotary dials, push buttons, and touch pads. User interface112may include a display component, such as a digital or analog display device designed to provide operational feedback to a user. User interface112may be in communication with controller116via one or more signal lines or shared communication busses.

It should be appreciated that the invention is not limited to any particular style, model, or configuration of dishwasher appliance. Thus, the exemplary embodiment depicted inFIGS. 1 and 2is for illustrative purposes only. For example, different locations may be provided for a user interface112, different configurations may be provided for rack assemblies130and132, and other differences may be applied as well.

Turning especially toFIGS. 2 and 3,FIG. 3illustrates a front, partial perspective view of a rack assembly (e.g., rack assembly130) according to an exemplary embodiment of the present disclosure (e.g., in an extended position). As described below, dishwasher appliance100includes one or more features for permitting easy removal/mounting of rack210within wash chamber106or movement of rack210to different heights (i.e., height settings) along the vertical direction V such that rack210may be placed in various predetermined positions along the vertical direction V. Although a rack210may be removable from wash chamber106and separable from the rest of dishwasher appliance100, the vertical direction V, lateral direction L, and transverse direction T described with respect to various elements of rack assembly130are, except as otherwise indicated, generally understood to correspond to the position of those elements when rack assembly130is mounted within wash chamber106and to the rest of appliance100(e.g., such that rack210can slide along a frame220in or along the transverse direction T).

It is noted that although adjustable rack assembly130is described as an upper rack assembly, alternative embodiments may include the adjustable rack assembly130at another suitable location (e.g., as a lower rack assembly). Moreover, although described within the context of a dishwasher appliance, the present disclosure may be utilized in any other suitable appliance, such as a refrigerator appliance.

In some embodiments, multiple rows of wheels bound a frame220of a corresponding slide assembly (e.g., slide assembly124) at each unique height setting (e.g., when rack assembly130, including removable rack210, is mounted within wash chamber106). As shown, a frame220of a slide assembly124may be mounted within wash chamber106at each lateral sidewall128of wash chamber106. In some embodiments, each frame220includes a pair of mated rails222,224. For instance embodiments, a first rail222may be fixed within wash chamber106(e.g., mounted to a sidewall128of wash chamber106). A second rail224may be slidably attached to first rail222. Generally, first and second rails222and224are mounted to each other such that first and second rails222and224are slidable relative to each other. For instance, the attachment between first and second rails222and224can permit movement or sliding of second rail224relative to first rail222along the transverse direction T (e.g., parallel to the transverse direction T). An internal bearing230positioned between the first and second rails222and224may, optionally, reduce friction and facilitate relative movement of first and second rails222and224. Moreover, although two rails222and224are illustrated, further embodiments may include additional rails or bearings slidably mounted to first and second rails222and224to permit further extension of frame220, as would be understood.

In some embodiments, a set of front wheels is provided on rack210(e.g., at each lateral side of rack210). For instance, the set of front wheels may include a first front wheel232A and a second front wheel232B at the same lateral side of rack210. In optional embodiments, a third front wheel232C is also included at the same lateral side. As would be understood, further optional embodiments may include additional front wheels.

As will be described below, front end cap240may receive or catch at least one wheel of the set of front wheels232A,232B,232C when rack210is pulled outward from wash chamber106(e.g., to the extended position) and may prevent excessive extension or travel of rack assembly130(e.g., along the vertical direction V T).

Each wheel of the set of front wheels232A,232B,232C may be attached to rack210. For example, each wheel232A,232B,232C may be rotatably attached to rack210(e.g., at a bracket fixed to rack210) to rotate about a unique rotation axis A. Each rotation axis A of front wheels232A,232B,232C may be parallel to the other rotation axes A of front wheels232A,232B,232C and, in certain embodiments, parallel to the lateral direction L (e.g., when rack210is mounted within wash chamber106and on frame220). When rack210is mounted on frame220(e.g., as illustrated inFIGS. 2 through 5), each front wheel232A,232B,232C is vertically aligned with the other front wheels232A,232B,232C. For instance, the front wheels232A,232B,232C may be positioned parallel to the vertical direction V such that each rotation axis A of the front wheels232A,232B,232C is orthogonal to a common line extending along the vertical direction V. Thus, first front wheel232A is vertically aligned to second front wheel232B. Third front wheel232C may further be vertically aligned to first front wheel232A and second front wheel232B. First front wheel232A may be positioned above second front wheel232B (e.g., in or along the vertical direction V when rack210is mounted to frame220). Second front wheel232B may be positioned above third front wheel232C (i.e., between first front wheel232A and third front wheel232C in or along the vertical direction V). When mounted to frame220, first front wheel232A may generally be positioned above frame220.

A unique height setting may be defined between each adjacent (e.g., vertically-adjacent) pair of front wheels232A,232B,232C. As an example, a first height setting may be defined along the vertical direction V between first front wheel232A and second front wheel232B. Rack210may thus be considered to be mounted at the first height setting when first front wheel232A is positioned over or above frame220(e.g., to rotate on or along an upper surface226of frame220) and second front wheel232B is positioned under or beneath frame220(e.g., to rotate or slide below a lower surface228of frame220). As another example, a second height setting may be defined below the first height setting. In particular, the second height setting may be defined along the vertical direction V between second front wheel232B and third front wheel232C. rack210may thus be considered to be mounted at the second height setting when second front wheel232B is positioned over or above frame220(e.g., to rotate on or along upper surface226of frame220) and third front wheel232C is positioned under or beneath frame220(e.g., to rotate or slide below lower surface228of frame220). When rack210is mounted at the second height setting, it is thus positioned higher (e.g., relative to the bottom portion of tub104—FIG. 2) than when rack210is mounted at the first height setting. Optional embodiments may include further height settings. Advantageously, rack210may have the same transverse extension or travel, regardless of the height setting at which it is mounted relative to frame220. In other words, rack210may be pulled out to the same transverse length at each of the predetermined height settings of rack assembly130.

In some embodiments, a set of rear wheels is provided on rack210(e.g., at each lateral side of rack210). The set of rear wheels may include a first rear wheel242A and a second rear wheel242B at the same lateral side of rack210. In optional embodiments, a third rear wheel242C is included at the same lateral side or rack210. Further optional embodiments may include additional rear wheels.

Each wheel of the set of rear wheels242A,242B,242C may be attached to rack210. For example, each rear wheel242A,242B,242C may be rotatably attached to rack210(e.g., at a bracket fixed to rack210) to rotate about a unique rotation axis A. Each rotation axis A of rear wheels242A,242B,242C may be parallel to the other rotation axes A of the rear wheels242A,242B,242C and, in certain embodiments, parallel to the lateral direction L (e.g., when rack210is mounted within wash chamber106and on frame220). In optional embodiments, when rack210is mounted on frame220(e.g., as illustrated inFIGS. 2 through 5), each rear wheel242A,242B,242C is vertically aligned with the other rear wheels242A,242B,242C.

For instance, the rear wheels242A,242B,242C may be positioned parallel to the vertical direction V such that each rotation axis A of rear wheels242A,242B,242C is orthogonal to a common line extending along the vertical direction V. Thus, first rear wheel242A may be vertically aligned to second rear wheel242B. Third rear wheel242C may further be vertically aligned to first rear wheel242A and second rear wheel242B. First rear wheel242A may be positioned above second rear wheel242B (e.g., in or along the vertical direction V when rack210is mounted to frame220). Second rear wheel242B may be positioned above third rear wheel242C (i.e., between first rear wheel242A and third rear wheel242C in or along the vertical direction V). When mounted to frame220, first rear wheel242A may generally be positioned above frame220.

As illustrated, the set of rear wheels242A,242B,242C is generally spaced apart from (e.g., rearward relative to) the set of front wheels232A,232B,232C in or along the transverse direction T. Each rear wheel242A,242B,242C may be transversely aligned with a corresponding front wheel232A,232B,232C (e.g., parallel to the transverse direction T such that each rotation axis A of a rear wheel242A,242B,242C is orthogonal to a common line extending along the transverse direction T to a corresponding front wheel232A,232B,232C). When rack210is mounted on frame220, at least one rear wheel242A,242B,242C may thus further support rack210on frame220. First rear wheel242A may be transversely aligned with first front wheel232A. Second rear wheel242B may be transversely aligned with second front wheel232B. Third rear wheel242C may be transversely aligned with third front wheel232C. A transverse spacing244may be defined between each transversely-aligned pair of front and rear wheels from the rotation axis A of a front wheel to the rotation axis A of the transversely-aligned rear wheel). Optionally, the transverse spacing244between each transversely-aligned may be equal.

With the set of front wheels232A,232B,232C, the set of rear wheels242A,242B,242C may further define the unique height settings. As an example, the first height setting may be further defined along the vertical direction V between first rear wheel242A and second rear wheel242B. In the first height setting, first rear wheel242A may be positioned over or above frame220(e.g., to rotate or slide on an upper surface226of frame220) and second rear wheel242B may be positioned under or beneath frame220(e.g., to rotate or slide on a lower surface228of frame220). As another example, the second height setting may be further defined along the vertical direction V between second rear wheel242B and third rear wheel242C. In the second height setting, second rear wheel242B may be positioned over or above frame220(e.g., to rotate or slide on an upper surface226of frame220) and third rear wheel242C may be positioned under or beneath frame220(e.g., to rotate or slide on a lower surface228of frame220).

An end cap240is attached to the frame220at a forward end thereof to catch one of the wheels (e.g., a front wheel232A,232B,232C) in an extended position and prevent excessive movement of the rack210(e.g., along the transverse direction T). A user can move rack210to adjust or shift upper rack assembly130upwardly or downwardly along the vertical direction V (e.g., relative to tub sump portion142or lower rack assembly132). Such adjustment can permit larger dishes to be loaded into upper or lower rack assemblies130and132.

Turning now toFIGS. 3 through 6,FIGS. 4 and 5illustrate a cross-sectional side view of rack assembly130as it moves between a retracted position (e.g., partially retracted position—FIG. 4) and an extended position (FIG. 5).FIG. 6illustrates a similar view wherein rack assembly130is in a tilted position (e.g., to be adjusted or removed from frame220).

As shown, when rack210is slidably mounted to frame220, a pair of wheels may bound frame220. In particular, at least one wheel (e.g., first front wheel232A) may be positioned on an upper surface226(e.g., uppermost vertical extreme) of frame220while another wheel (e.g., second front wheel232B) may be positioned below a lower surface228(e.g., lowermost vertical extreme) of frame220. In some embodiments, each of the bounding wheels defines a wheel radius246. Each wheel radius246may extend from a corresponding rotation axis A to a rolling contact surface248of wheel. As an example, in the illustrated embodiments and positions ofFIGS. 4 and 5, the wheel radius246of first front wheel232A extends perpendicularly from the corresponding rotation axis A and to the rolling contact surface248, which rotates along upper surface226(e.g., in contact therewith). In some embodiments, each bounding wheel (e.g., each wheel of the set of front wheels232A,232B,232C) defines a wheel radius246that is equal to the wheel radius246of the other wheel(s). Thus, first front wheel232A may define a wheel radius246, and second front wheel232B may define a wheel radius246that is equal (e.g., in length or magnitude) to the wheel radius246of the first front wheel232A.

Optionally, one or more guide flares250may extend radially outward from the contact surface248of each wheel (e.g., at opposite lateral sides of the corresponding wheel) and laterally bound frame220to maintain lateral alignment between the wheel and frame220.

Turning now toFIGS. 4 through 9,FIGS. 7 through 9illustrate various views of end cap240according to exemplary embodiments. As shown, end cap240may be attached to frame220(e.g., at a forward end thereof). For example a friction fit may be formed between end cap240and second rail224(e.g., such that end cap240slides with second rail224relative to first rail222). Additionally or alternatively, a suitable mechanical fastener or adhesive may join end cap240to frame220(e.g., at second rail224).

End cap240generally defines an outer profile across which one or more of the wheels (e.g., front wheels232A,232B,232C) may move. This outer profile may include a top-end catch profile252(TCP) and a bottom-end relief profile254(BRP). When assembled (e.g., when end cap240is attached to frame220), TCP252is directed rearward along the transverse direction T. Thus, TCP252generally faces wash chamber106(FIG. 2) and a back wall thereof. If viewed from inside the wash chamber106and, for example, at the same vertical height as end cap240, TCP252may be visible. In contrast to TCP252, BRP254is directed forward along the transverse direction T. Thus, BRP254generally faces away from wash chamber106(FIG. 2) and toward the region in front of appliance100(FIG. 2). If viewed from outside wash chamber106(e.g., directly in front of appliance100with the door120—FIG. 2—opened) and, for example, at the same vertical height as end cap240, BRP254may be visible. When assembled, TCP252extends smoothly or uninterrupted from upper surface226such that, for instance, first front wheel232A may roll or slide smoothly from upper surface226to TCP252. Additionally or alternatively, BRP254extends smoothly or uninterrupted from lower surface228such that, for instance, second front wheel232B may roll or slide unhalted from a point directly beneath lower surface228to a point directly beneath BRP254.

Generally, TCP252has a separate transverse profile segment256and vertical profile segment258. As illustrated, vertical profile segment258extends from and above transverse profile segment256. In particular, vertical profile segment258extends generally in vertical direction V from a base point262at transverse profile segment256to a vertical tip260positioned higher than base point262in the vertical direction V. The vertical tip260may define the upper extreme of vertical profile segment258or end cap240along the vertical direction V. Transverse profile segment256may extend parallel to the transverse direction T and, for example, from the upper surface226of frame220. In particular, transverse profile segment256may define a surface parallel to the transverse direction T extending from a start point264to the base point262.

In the extended position, vertical profile segment258may generally receive the corresponding front wheel (e.g., first front wheel232A) as it slides or rolls forward from transverse profile segment256. In some such embodiments, vertical profile segment258is positioned forward relative to front wheel232A,232B,232C (e.g., further from wash chamber106in the transverse direction T). Engagement or contact between the front wheel232A,232B,232C and vertical profile segment258may halt further forward transverse movement of rack210. In optional embodiments, when rack210is mounted to frame220(e.g., in the extended position), vertical tip260is positioned above (e.g., higher in the vertical direction V) than the rotation axis A of a corresponding front wheel (e.g., first front wheel232A). In such embodiments, the vertical distance between vertical tip260and the rotation axis A is defined as a vertical excess280.

In certain embodiments, vertical profile segment258is gradually curved upward. In other words, the outer surface of vertical profile segment258extends arcuately in transverse direction T and vertical direction V from transverse profile segment256to the vertical tip260. The curvature of vertical profile segment258may define a vertex (e.g., top vertex266). Moreover, the curvature may define a radius (e.g., top arcuate radius268) extending rearward from vertical profile segment258. For instance, the top arcuate radius268may extend from the top vertex266. In exemplary embodiments, top arcuate radius268is greater than or equal to the wheel radius246of the corresponding front wheel (e.g., first front wheel232A). As rack210moves between a retracted and extended position, the corresponding front wheel232A may advantageously move smoothly to/from the extended position without inadvertently rolling above the vertical tip260.

In optional embodiments, the curvature of vertical profile segment258defines a constant radius between transverse profile segment256and vertical tip260. Top vertex266may be defined at the midpoint between transverse profile segment256and vertical tip260. As shown, vertical profile segment258generally defines a discrete inner transverse length270and top vertical height272from start point264to vertical tip260. In certain embodiments, the top vertical height272is greater than the diameter of the corresponding front wheel (i.e., double the wheel radius246). In additional or alternative embodiments, the inner transverse length270is less than the diameter of the corresponding front wheel. As an example, the inner transverse length270may be between about 95% and about 100% of the diameter. As another example, the inner transverse length270may be about 99% of the diameter.

In some embodiments, BRP254generally defines a slightly sloped or S-shaped surface generally extending rearward from a front point274(e.g., outermost extreme in the transverse direction T) to a rear point276(e.g., innermost extreme in the transverse direction T) opposite from TCP252. An outer transverse length278may be defined along the transverse direction T between front point274and rear point276. As shown, outer transverse length278may be longer than inner transverse length270. Rear point276may generally be at the same vertical height as lower surface228of frame220. Moreover, rear point276may define the lowermost point of end cap240along the vertical direction V. In some such embodiments, when rack210is mounted to frame220in the extended position, rear point276is positioned directly above a portion of the corresponding front wheel (e.g., second front wheel232B). The vertical distance between rear point276and the surface of the corresponding wheel232B directly beneath rear point276may be defined as a vertical gap282. Optionally, the ratio of the vertical gap282over the vertical excess280may be a predefined clearance ratio between about 1.0 and about 2.0. Additionally or alternatively, the clearance ratio may be about 1.3.

A concave profile segment286of BRP254may extend from rear point276to a convex profile segment284, which itself may extend to front point274. An intermediate segment288may connect BRP254and TCP252(e.g., extending generally along the transverse direction T from vertical tip260to front point274).

When rack210is in the extended position, at least a portion of BRP254is positioned rearward relative to a corresponding front wheel (e.g., second front wheel232B) beneath BRP254. For example, a portion of concave profile segment284may be positioned further rearward and closer to wash chamber106(FIG. 2) in the transverse direction T than an outermost (i.e., forward most) surface of the corresponding wheel. In some embodiments, concave profile segment286defines a vertex (e.g., bottom vertex290). In some such embodiments, the bottom vertex290is positioned rearward relative to the rotation axis A of the corresponding front wheel232B in the transverse direction T. In other words, bottom vertex290is behind the rotation axis A of the corresponding front wheel232B. In additional or alternative embodiments, bottom vertex290is defined or positioned rearward relative to (e.g., behind) top vertex266. In further additional or alternative embodiments, bottom vertex290is defined or positioned rearward relative to (e.g., behind) at least a portion of transverse profile segment256in the transverse direction T. A radius (e.g., bottom arcuate radius292) may be defined to extend forward from bottom vertex290. In exemplary embodiments, bottom arcuate radius292is greater than or equal to the wheel radius246of the corresponding front wheel (e.g., second front wheel232B).

As shown, especially atFIG. 6, removal of rack210(e.g., from the extended mounted position) may be permitted by tilting rack210relative to frame220. The above-described embodiments and features may advantageously permit rack210to be inclined to the tilted position illustrated atFIG. 6. For instance, rack210may tilt about the upper wheel resting on frame220(e.g., about first rear wheel242A—FIG. 3). In the tilted position, the upper front wheel (e.g., first front wheel232A) is lifted above the vertical tip260of end cap240. The lower front wheel (e.g., second front wheel232B) may be received within a portion of BRP254(e.g., within concave segment286). In certain embodiments, the angle of incline for rack210relative to the extended position is a preset angle between, for instance, about 2.0° and about 5.0°. In other words, the difference in orientation of rack210between the extended position and the tilted position is defined by the preset angle. From the tilted position, rack210may be pulled forward along the transverse direction T and removed from frame220. Once removed, rack210may be moved to a new (or returned the same) height setting. Mounting rack210to frame220may generally follow a reverse motion from removal.