Auto laundry conveyor dolly

A car wash dolly that uses a single shaft having two camshaft lobes and a series of snap ring grooves. The bolt-less design of the dolly includes a stronger camshaft and minimized component count. The center link and wheels may be mounted directly on the shaft to produce a sturdy design for the dolly. Grooves and snap rings are provided to “lock” wheels in their place on the shaft and to keep wheels physically close to one another to prevent dirt or other debris from getting between the wheels. Optional thrust washers also may be provided between plastic wheels and snap rings to reduce friction between the wheels during operation of the dolly in a car wash facility. The dolly according to the present disclosure is intended to roll, via a conveyor chain, on a slotted track of an auto-laundry system. Because of rules governing Abstracts, this Abstract should not be used to construe the claims in this patent application.

BACKGROUND

1. Field of the Disclosure

The present disclosure generally relates to the field of auto-laundry systems of the type employing an endless loop chain conveyor linking a plurality of car-pusher dollies that roll along slotted tracks, and, more particularly, to a car wash dolly design that uses a single, solid shaft with two camshaft lobes and a series of snap ring grooves.

2. Brief Description of Related Art

Certain auto-laundry systems, otherwise popularly known as “car washes,” use endless chain conveyors of the type having “dollies” linked into the continuous-loop chain of a conveyor at regular intervals. These dollies are used to push vehicles along a track by engaging the tread surface of the tires of the vehicle. The dollies, in turn, are connected into the continuous loop chain by means of a center link.

The track structure which is used in combination with the chain and the dollies typically comprises three separate tracks mounted in parallel and at different levels. The top track accommodates the tire of the vehicle being washed and also provides the travel path for dollies which are selected at any given time to push the vehicle along the track. An intermediate level track provides the forward track for unselected dollies to continue to move on, and the bottom level track provides a return path for the dollies. A selector is used to transfer dollies from the intermediate to the top level tracks when a vehicle is present to be conveyed.

The U.S. Pat. No. 7,243,605 to Belanger et al. describes a car wash dolly design that utilizes a steel axle member in the form of a steel bolt having a threaded end which receives a nut. A center link is mounted on the axle member and three different pairs of wheels are mounted on the axle member on opposite sides of the center link. Bearings are provided between all of the wheels for independent rotation of the wheels.

A dolly employing such a bolt-based design includes many lose parts that are “assembled” via the bolt which holds bushing tubes for each wheel, wheels, and the center link in place to produce the final structure. In other words, a single, thin bolt is forced to carry many components and hold them in place while bearing the weight of a vehicle. This arrangement frequently leads to bending of the bolt during operation, thereby necessitating removal and replacement of the damaged dollies. Furthermore, the bolt and nut engagement may become lose under certain operational conditions. Hence, the bolt-based dolly design may be commercially undesirable because it leads to a reduced lifespan of the dolly, resulting in expensive repairs/replacements.

SUMMARY

In one embodiment, the present disclosure relates to a car wash dolly having a stronger camshaft with bolt-less design and minimized component count. The center link and wheels may be mounted directly on the shaft to produce a sturdy design for the dolly. Grooves and snap rings are provided to keep wheels close to one another to prevent dirt or other debris from getting between the wheels. The dolly is intended to roll, via a conveyor chain, on a slotted track of a car wash system.

In an embodiment, an auto-laundry conveyor dolly of the type intended to roll on a slotted track is provided. The dolly includes a shaft and a center link having a chain attachment portion for attachment to a chain of the auto-laundry conveyor and a circular portion that encircles the shaft, the circular portion being attached to the shaft by a pin passing through the circular portion of the center link and into the shaft.

In an embodiment, an auto-laundry conveyor dolly of the type intended to roll on a slotted track is provided that includes a metal shaft with a plurality of grooves formed in the metal shaft. One or more wheels are furthermore mounted on the shaft between pairs of physically-adjacent grooves. A snap ring may furthermore be inserted into each groove to retain the wheels in their places.

In a further embodiment, the present disclosure relates to a shaft for an auto-laundry conveyor dolly. The shaft comprises a cylindrical metal tube that includes a cylindrical central portion, a pair of central grooves, a pair of cylindrical side portions, a pair of side grooves, a pair of cylindrical side lobes, and a pair of end grooves. The cylindrical central portion is configured to receive a pair of inner wheels and a center link. The pair of cylindrical side portions is formed on opposite sides of the central portion by forming or cutting a pair of central grooves into the metal tube at corresponding ends of the central portion, wherein both of the side portions and the central portion are coaxial and of substantially the same external diameter, and wherein each side portion is configured to receive a corresponding one of a pair of intermediate wheels. The pair of side grooves is cut into the metal tube at opposite outer ends of the pair of side portions and is coaxial with the pair of side portions. A pair of cylindrical side lobes is formed on both ends of the metal tube at opposite outer sides of the pair of side grooves, wherein each side lobe in the pair of side lobes is linked to a respective side portion in the pair of side portions via a corresponding side groove from the pair of side grooves and is configured to receive a corresponding one of a pair of outer wheels, and wherein centers of the pair of side lobes are axially offset from the centers of the pair of side portions and the central portion. The pair of end grooves is cut into the metal tube at opposite outer ends of the pair of side lobes and being coaxial with the pair of side lobes.

In another embodiment, the present disclosure relates to an auto-laundry conveyor dolly of the type intended to roll on a slotted track. The dolly comprises a shaft made of a cylindrical metal tube that includes: (i) a cylindrical central portion, (ii) a pair of cylindrical side portions on opposite sides of the central portion, wherein the pair of side portions is formed by forming or cutting a pair of central grooves into the metal tube at corresponding ends of the central portion, and wherein both of the side portions and the central portion are coaxial and substantially of the same external diameter, (iii) a pair of side grooves cut into the metal tube at opposite outer ends of the pair of side portions and being coaxial with the pair of side portions, (iv) a pair of cylindrical side lobes formed on both ends of the metal tube by forming the metal tube at opposite outer sides of the pair of side grooves, wherein each side lobe in the pair of side lobes is linked to a respective side portion in the pair of side portions via a corresponding side groove from the pair of side grooves, and wherein centers of the pair of side lobes are axially offset from the centers of the pair of side portions and the central portion, and (v) a pair of end grooves cut into the metal tube at opposite outer ends of the pair of side lobes and being coaxial with the pair of side lobes. The dolly further comprises: a center link attached to the central portion for connecting the dolly into a conveyor chain of the slotted track; a pair of inner wheels mounted on the central portion on opposite sides of the center link and sandwiched between the pair of central grooves; a first pair of open-ended snap rings non-movably inserted into the pair of central grooves; a second pair of open-ended snap rings non-movably inserted into the pair of side grooves; a pair of intermediate wheels mounted on the pair of side portions between the first pair of snap rings and the second pair of snap rings, wherein the intermediate wheels are coaxial with and substantially of the same internal diameter as the inner wheels; a third pair of open-ended snap rings non-movably inserted into the pair of end grooves; and a pair of outer wheels mounted on the pair of side lobes between the second pair of snap rings and the third pair of snap rings, wherein the outer wheels being axially offset from and of a smaller internal diameter than the intermediate wheels.

In a still further embodiment, the present disclosure relates to an auto-laundry dolly connected to a conveyor chain of a slotted track of an auto-laundry facility. In addition to the components discussed above in the preceding paragraph, the dolly may further comprise a cross-sectionally substantially circular pin hole drilled into the middle of a surface of the central portion, wherein the top surface is longitudinally substantially aligned with respective top surfaces of the pair of side lobes and the pair of side portions. The center link attached to the central portion may comprise a link hole of substantially the same diameter as the pin hole. The dolly may further comprise a cylindrical pin inserted through the link hole and the pin hole to thereby non-movably attach the center link to the central portion for connecting the dolly into the conveyor chain of the slotted track. A first pair of thrust washers may be mounted on the central portion on opposite sides of the center link between the inner wheels and the center link, and a second pair of thrust washers may be mounted on the pair of side portions between the first pair of snap rings and sides of the intermediate wheels adjacent to the first pair of snap rings.

Accordingly, the present invention provides solutions to the shortcomings of prior auto-laundry dollies and components of auto-laundry dollies, methods of using auto-laundry dollies and components of auto-laundry dollies, and systems using auto-laundry dollies and components of auto-laundry dollies. Those of ordinary skill in the construction and operation of auto-laundries will readily appreciate that those details described above and other details, features, and advantages of the present invention will become further apparent in the following detailed description of the preferred embodiments of the invention.

DETAILED DESCRIPTION

The accompanying figures and the description that follows set forth the present disclosure in embodiments of the present disclosure. However, it is contemplated that persons generally familiar with mechanical designs, and more particularly with designs of car wash dollies, will be able to apply the teachings of the present disclosure in other contexts by modification of certain details. Accordingly, the figures and description are not to be taken as restrictive of the scope of the present disclosure, but are to be understood as broad and general teachings. In the discussion herein, when any numerical value is referenced, such value should be understood to be the most practically-feasible design approximation taking into account variances that may be introduced by such mechanical operations as machining, tooling, drilling, etc.

It is observed at the outset that the directional terms such as “top,” “bottom,” “right,” “left,” “horizontal,” “vertical,” “upper,” “lower,” etc., and derivatives thereof are used hereinbelow for illustrative purpose only to facilitate description and understanding of relative positions of various mechanical components or parts constituting the car wash dolly according to the teachings of the present disclosure. Hence, such terms and derivatives thereof shall relate to the present disclosure as it is oriented in the drawing figures provided herein.

It is further observed here that the mechanical structures, components, assemblies, or engineering drawings thereof illustrated in various figures in the instant application are not drawn to scale, but are rather illustrated for the convenience of understanding various design aspects of a car wash dolly according to the teachings of the present disclosure.

Any reference in the specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of phrases such as “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment. References to “or” are furthermore intended as inclusive so “or” may indicate one or another of the ored terms or more than one ored term.

FIG. 1illustrates a partial, simplified view of an exemplary auto-laundry or car wash system10employing dollies12A through12F according to one embodiment of the present disclosure. A car14is shown to have entered the car wash system10with its tires placed on tracks15A through15D. Although not clearly visible inFIG. 1, it is noted here that in the slotted-track car wash system10, each tire of the car14spans two adjacent tracks. Thus, for example, the tires T1and T2will typically remain placed on the tracks15C and15D during the auto laundry operation. Two, track-specific conveyor chains16,17are also shown inFIG. 1. As is known in the art, each of these conveyor chains16,17operates in an endless loop pulling the dollies12A-12F along the track. The conveyor chains16,17may run under the gap or “slot” between adjacent tracks. The conveyor chains16,17along with the dollies that are selected to engage with car tires—e.g., the dollies12E and12F in FIG.1—push the tires (and, hence, the car) along the tracks during the car wash operation. The unselected dollies (e.g., the dollies12A-12D inFIG. 1) will continue to move on along corresponding tracks via respective conveyor chains as is known in the art.

It is noted here that the simplified depiction of the dollies12A-12F inFIG. 1is for illustrative purpose only. The actual shape and constructional details of these dollies12A-12F are illustrated more accurately and described in further detail below with reference to discussion of dolly25inFIGS. 2 through 12. It is further noted here that the constructional details of tracks15A-15D (e.g., track slots, track rails, cross beams, support assemblies, etc.) and conveyor chains16-17are not shown inFIG. 1for ease of illustration, because of their lack of relevance to the present discussion, and because of the availability of many known configurations for these elements of a car wash system. In an operational car wash system, the dollies according to the present disclosure may be used in conjunction with various presently-available slotted track and conveyor designs, which can be selected as desired.

FIG. 2shows a fully-assembled view of an exemplary dolly25according to one embodiment of the present disclosure. In one embodiment, each of the dollies12A-12F in the car wash system ofFIG. 1may be identical to the dolly25inFIG. 2. In the dolly25shown inFIG. 2, a center link26is attached to a central portion of a shaft34(not visible inFIG. 2, but shown, e.g., inFIGS. 3,4,8, and12). A link hole27(discussed later below) is visible in the center link26is visible inFIG. 2. The dolly25includes a first substantially identical pair of inner wheels28A-28B, a second substantially identical pair of intermediate wheels30A-30B, and a third substantially identical pair of outer wheels32A-32B mounted on opposite sides of the center link26in corresponding pairs as shown inFIG. 2. As is known in the art, the inner wheels28A-28B may primarily be disposed in a slot (such as slot16and17illustrated inFIG. 1) centered between opposite longitudinally extending track rails (such as tracks15A-15D illustrated inFIG. 1) and may remain in rolling contact with a car's tires (not shown) when a car is situated thereon. The intermediate wheels30A-30B are arranged axially with the inner wheels28A-28B and are generally in rolling contact with the tracks (such as tracks15A-15D illustrated inFIG. 1) so as to permit the dolly25to roll along the tracks. The outer wheels32A-32B are arranged in an axially offset manner to ride along the lower track, such as the bottom side of tracks15C and15D, when the dolly25is not engaged with a vehicle and moving along the lower track. The outer wheels32A-32B may ride along a wear strip (not shown) when the associated dolly25is operating on the upper track15C,15D or may be idle when the dolly25is operating on the upper track15C,15D and no wear strip is present. In various embodiments, each type of wheel—an inner wheel, an intermediate wheel, or an outer wheel—may have various dimensions.

FIG. 3depicts an exemplary set of components that may be used to assemble the dolly25illustrated inFIG. 2according to one embodiment of the present disclosure. For simplicity of illustration, only one wheel28A,30A, and32A from the corresponding pair of wheels is shown inFIG. 3. Although not visible inFIG. 2, it is seen fromFIG. 3that the dolly25may comprise of a cylindrical shaft34designed to receive various other components of the dolly25. The shaft34may function as a “foundation” upon which other components of the dolly25may be mounted. The other such components include the three pairs of wheels—the inner wheels28A-28B, the intermediate wheels30A-30B, and the outer wheels32A-32B, the center link26with the link hole27(discussed later hereinbelow) drilled therein to align with a pin hole36drilled on the top of the central portion of the shaft34, a metallic pin (not shown inFIG. 3, but illustrated as pin60inFIGS. 9-10) inserted through holes27and36to hold the dolly25in the desired clocked position for use in the conveyor, and three pairs of open-ended snap rings (one such snap ring38with two ends38A and38B is shown inFIG. 3and discussed in more detail later with reference toFIG. 11) that are inserted into and retained within corresponding grooves (not identified inFIG. 3, but discussed later with reference toFIG. 4) to maintain the wheels (e.g., wheels28A,30A, etc.) in their given shaft locations during operation of the dolly25. The grooves and snap rings maintain the wheels in close proximity to one another to minimize accumulation of dirt or other debris between the wheels. In one embodiment, the dolly25may also optionally include at least two pairs of thrust washers or “spacers” (one such washer40is shown inFIG. 3and discussed in more detail later hereinbelow) between adjacent pairs of wheels to reduce friction between the wheels. In one embodiment, one pair of washers40may be placed on each side of the center link26and thus be positioned between the center link26and the pair of inner wheels28A-28B. A second pair of washers40may be placed between the inner wheels28A-28B and their adjacent intermediate wheels30A-30B as shown in the exemplary partial illustration inFIG. 11. A third pair of washers40may be placed between the intermediate wheels30A-30B and the outer wheels32A-32B.

In the embodiment ofFIG. 3, the internal diameter ID1of an inner wheel (e.g., the wheel28A) may be substantially the same as the internal diameter ID2of an intermediate wheel (e.g., the wheel30A). On the other hand, the internal diameter ID3of an outer wheel (e.g., the wheel32A) may be smaller than the internal diameter ID1of an intermediate wheel or the diameter ID2of an inner wheel. On the other hand, in one embodiment, the external diameter ED1of an inner wheel (e.g., the wheel30A) may be larger than the external diameter ED2of an intermediate wheel (e.g., the wheel30A) or the external diameter ED3of an outer wheel (e.g., the wheel32A). In one embodiment, the external diameter ED2of an intermediate wheel is larger than the external diameter ED3of an outer wheel. As illustrated in the embodiment ofFIGS. 2-3, each intermediate wheel may be length-wise longer than either an inner wheel or an outer wheel, whereas an outer wheel may be length-wise longer than an inner wheel. The “lengths” of individual wheels are indicated by references “RL1,” “RL2,” and “RL3” inFIG. 3. As mentioned before, in one embodiment, each of the wheels28A-28B,30A-30B, and32A-32B may be made of plastic sufficiently hardened to withstand the wear and tear inherent in a car wash operation.

FIG. 4shows exemplary structural details of the shaft34illustrated inFIG. 3. As shown inFIG. 3, the dolly25may include a single, one piece shaft34that may be formed from one piece of metal or multiple pieces of metal welded or otherwise formed into such a single piece. FromFIG. 4, it is seen that the shaft34may be made in the form of a single, hollow, cylindrical tube41. The tube41may furthermore be formed of metal, such as steel in a form that is resistant to corrosive surroundings, such as those that typically exist in an auto-laundry. The tube41may include a cylindrical central portion42that may receive the pair of inner wheels28A-28B and the center link26(for example, using a pin inserted through the pin hole36, which is not clearly visible in the view ofFIG. 4). The tube41may further include a pair of cylindrical side portions43,44on opposite sides of the central portion42. The side portions43,44may be formed by cutting a pair of central grooves45,46into the metal tube41at corresponding ends of the central portion42. It is seen fromFIG. 4that the side portions43-44and the central portion42may be coaxial and of substantially the same external diameter. Each side portion43,44may receive a corresponding intermediate wheel30A,30B as illustrated in the assembled view of the dolly25inFIG. 2. Side grooves47,48may be cut into the metal tube41at opposite outer ends of the corresponding side portions43,44as illustrated inFIG. 4. Each side groove47,48may be coaxial with its adjacent side portion43,44(and, hence, also may be coaxial with the central portion42). The cutting of side grooves47,48may result in the formation of side groove boundaries49,50. As shown in the embodiment ofFIG. 4, the shaft34also includes a pair of cylindrical side lobes51,52that are formed on both ends of the tube41. The cylindrical side lobes51,52may be formed by machining the tube41at opposite outer sides of the pair of side grooves47,48(i.e., beyond the side groove boundaries49,50), casting the tube41with the side lobes51,52, attaching the side lobes51,52to the tube41by, for example, welding, or otherwise forming the side lobes51,52on the tube41, as desired. Each side lobe51,52may receive a corresponding outer wheel32A,32B as shown inFIG. 2.

In the embodiment illustrated inFIG. 4, the shaft34is made of metal and may be made of 1045 heat-treated and chromed (HTC) steel. The shaft34includes a plurality of grooves45,46,47,48,53,54formed into the metal shaft34. The wheels28A,28B,30A,30B,32A,32B are mounted on the shaft34between pairs of physically-adjacent grooves45,46,47,48,53,54. Snap rings38are placed in the grooves45,46,47,48,53,54to retain the wheels28A,28B,30A,30B,32A,32B in their desired positions on the shaft34.

Some or all of the wheels28A,28B,30A,30B,32A,32B may have indentations on one or both sides to accommodate snap rings38and thrust washers40where desired and maintain the wheels28A,28B,30A,30B,32A,32B in close proximity. Maintaining the wheels28A,28B,30A,30B,32A,32B in close proximity has various benefits including minimizing collection of dirt between the wheels28A,28B,30A,30B,32A,32B. Thus, the wheels28A,28B,30A,30B,32A,32B are formed with a hole through the center of the wheel28A,28B,30A,30B,32A,32B defining an inner diameter of each wheel28A,28B,30A,30B,32A,32B. The wheels28A,28B,30A,30B,32A,32B also have an outer surface defining an outer diameter of each wheel28A,28B,30A,30B,32A,32B, and the wheels28A,28B,30A,30B,32A,32B have a first side and a second side. Where a side indentation is desired on one or more of the wheels28A,28B,30A,30B,32A,32B the indentation may be formed on one or both sides of the wheel28A,28B,30A,30B,32A,32B extending from the hole toward the outer surface, but not extending as far as the outer surface, as is shown on wheels30A and32A inFIG. 3.

In the embodiment illustrated inFIG. 3, the center link26includes a chain attachment portion20for attaching the dolly25to a conveyor chain and a circular portion22for encircling the shaft34. In an embodiment, the circular portion22is attached to the shaft34by a pin60(shown inFIGS. 9-10) passing through the link hole27drilled or otherwise formed in the circular portion22of the center link26and into the pin hole36formed by drilling or otherwise in the shaft34. Once the center link26is attached to the shaft34, the first inner wheel28A is placed on one side of the center link26and the second inner wheel28B is placed on the opposite side of the center link26. A thrust washer40may be placed between each of the inner wheels28A,28B and the center link26. An additional thrust washer40may then be placed on the outside of each of the inner wheels28A,28B and a snap ring38may be placed in shaft grooves45and46to hold the inner wheels28A,28B in place. A thrust washer40may then be placed around the shaft34and against the outer side of the snap rings38placed in shaft grooves45and46and intermediate wheels34A,34B are placed on opposite ends of the shaft34and moved against the snap rings38or thrust washers40where they are used. A thrust washer40may next be placed on the outside of each of the intermediate wheels30A,30B and a snap ring38may be placed in shaft grooves47and48to hold the intermediate wheels30A,30B in place. A thrust washer40may be placed around the lobes51and52of the shaft34if desired and the first outer wheel32A may be placed on the first lobe51and the second outer wheel32B may be placed on the second lobe52. Where desired, a thrust washer40may be placed against the outer sides of the outer wheels32A,32B and a snap ring38is inserted into shaft groove53to hold the first outer wheel32A in place and another snap ring38is inserted into shaft groove54to hold the second outer wheel32B in place.

It is observed here that although the side portions43,44and the central portion42are coaxial, the centers of the side lobes51,52may be axially offset from the centers of the side portions43,44and the central portion42. This axially offset formation of side lobes51,52allows the outer wheels32A,32B to ride along the bottom of the track15C,15D when not engaged with a vehicle and to ride above and out of contact with the car wash tracks during operation of the dolly25in engaged operation with a vehicle. Referring again toFIG. 4, it is seen that a pair of end grooves53,54also may be cut into the tube41at opposite outer ends of the pair of side lobes51,52. Each end groove53,54may be coaxial with its corresponding side lobe51,52as illustrated inFIG. 4. It is noted here that the cutting or forming of the end grooves53,54may result in the formation of end groove boundaries55,56. The dimensions of various portions formed on the tube41are discussed hereinbelow with reference toFIGS. 6 and 7.

It is noted here thatFIG. 4shows an exemplary placement of the grooves45-48and53-54. For example, in different embodiments, the grooves45-48may be placed at different locations along the shaft34, thereby changing the lengths of the central portion42, the side portions43-44, and the side lobes51-52from those shown inFIGS. 4and6B. For example, in one embodiment, the size of the wheels28A-B,30A-B, and32A-B to be fitted onto the dolly25may dictate the length of the shaft34as well as the placement of the grooves on the shaft34. The width and depths of the grooves in other embodiments may be different as well from those shown inFIG. 6A. Such design flexibility is contemplated as part of the construction of the dolly25according to the teachings of the present disclosure.

In one embodiment, the tube41(and, hence the shaft34) is made of 1045 heat treated and chromed (HTC) steel. As is known, the heat treatment hardens the steel, thereby allowing the dolly25to withstand the operational conditions existing in a typical car wash facility. It is seen here that the dolly25does not use an assembly of metal parts, but rather uses one shaft34that has two lobes51,52formed thereon, one lobe51,52being formed on each end of the shaft34.

FIG. 5illustrates a close-up view of a portion of the camshaft34illustrated inFIG. 4. InFIG. 5, shaft elements on the right side of the central portion42are shown in more detail to more clearly illustrate various groove formations and shaft geometry. Typically, similar shaft elements would be symmetrically present on the left side of the central portion42as well as the right side illustrated inFIG. 5(as can be seen fromFIGS. 2 and 4). InFIG. 5, the cylindrical side portion44and the cylindrical side lobe52are shown in a close-up view, thereby more clearly identifying the side groove48, the side groove boundary50, the end groove54, and the end groove boundary56.

FIGS. 6A through 6Cdepict a top view, a side view, and an end view, respectively and dimensional details of the shaft34shown inFIG. 4. As noted before, the diagrams inFIGS. 6A-6C(and those inFIGS. 7A-7B) are not drawn to scale, but are merely to facilitate better understanding of the structural details of the shaft34.FIG. 6Ashows the top view of the shaft34with side lobes51,52at the bottom (instead of at the top as inFIG. 4).FIG. 6Aidentifies all shaft34portions, grooves, and groove boundaries in correspondence with the three-dimensional view of the shaft34inFIG. 4and, hence, additional details of these structural parts of the shaft34are not repeated herein for the sake of brevity. In one embodiment, each of the six grooves—45,46,47,48,53, and54—is of identical width, which is indicated by reference letters “GW” inFIG. 6A. Similarly, in one embodiment, each of these six grooves is of identical depth (indicated by reference letters “GD” inFIG. 6A) from the corresponding outer surface. In another embodiment, each of the four groove boundaries—49,50,55, and56—is of the same width, which is indicated by the reference letters “BW” inFIG. 6A. In one embodiment, GW is approximately 0.072 inch, GD is approximately 0.062 inch, and BW is approximately 0.063 inch. Hence, it is observed fromFIG. 6Athat the shaft34as illustrated inFIGS. 6A-6Cmay be a substantially symmetrical structure with similar parts having substantially similar dimensions.

FIG. 6Bprovides a side view of the shaft34with the side lobes51,52at the bottom. It is noted here that the reference numerals inFIG. 6Aare not repeated inFIG. 6Bto maintain clarity in the drawings and to avoid clutter.FIG. 6Bidentifies axial lengths of various portions of the shaft34according to one embodiment of the present disclosure. The length of the entire tube41(and, hence, the length of the entire shaft34) is indicated by reference letter “L,” the length of the central portion42is indicated by reference indicator “L1,” the length of each side portion43,44is indicated by reference indicator “L2,” the length of the shaft excluding the side lobe portions is indicated by reference indicator “L3,” and the length of each side lobe51,52is indicated by reference indicator “L4.” In one embodiment, L is approximately 10.76 inches, L1is approximately 2.56 inches, L2is approximately 2.35 inches, L3is approximately 7.67 inches, and L4is approximately 1.41 inches.

FIG. 6Cshows an end view for the corresponding side view illustrated inFIG. 6B. The axially offset orientation of the side lobes51,52is clearly evident from the spacing or offset “S” between the centers of the two circles: (i) a first circle representing as “D1” the external diameter of the shaft portion that includes the central portion42and two side portions43,44(but excludes the side lobes51,52), and (ii) a second circle representing as “D2” the external diameter of each side lobe51,52. In one embodiment, D1is approximately 1.875 inches, D2is approximately 1.375 inches, and S is approximately 0.25 inch.

FIGS. 7A and 7Bshow additional dimensional details of the camshaft34illustrated inFIG. 4. As mentioned earlier, in one embodiment, the tube41is a hollow, cylindrical tube. In that regard,FIGS. 7A and 7Billustrate the dimensions of various holes formed into the tube41. A pair of large “outer” holes (OH1,OH2), each having a diameter of “D3,” may be formed, for example by drilling a predetermined distance “L5” (from each end of the tube41) into the tube41from both outer ends of the tube41as shown inFIG. 7A. In one embodiment, D3is approximately 1 inch, and L5is approximately 4 inches. These outer holes (OH1, OH2) may function as lightning holes to remove some of the mass from the shaft34, thereby reducing the weight of the shaft34without negatively impacting its strength under operational conditions. It is seen fromFIG. 7Athat the diameter “D3” of each outer hole OH1, OH2may be considered as defining the “internal” diameter of its corresponding side lobe51or52.

In one embodiment, an “inner” hole (IH) having a diameter “D4” (which may be smaller than the diameter “D3” of each outer hole OH1, OH2) and having a length “L6” also may be drilled into the tube41between the pair of outer holes. The inner hole (IH) may remain coaxial with its adjacent outer holes (OH1, OH2) as shown inFIG. 7A. However, in an alternative embodiment, different relative placement of the inner and outer holes also may be contemplated. Furthermore, the outer holes (OH1, OH2) may not be axially symmetrical (coaxial) with the side lobes51,52in another embodiment. In the embodiment ofFIG. 7A, D4is approximately 0.5 inch and L6is approximately 2.76 inches. In one implementation, the inner hole (IH) may be initially drilled through the entire steel tube41after heat treating the tube41. The chrome plating of the shaft34may be then performed. Subsequently, additional metal may be drilled out of the tube41to form the outer holes OH1, OH2.

In the front view ofFIG. 7A, the cross-sectionally substantially circular pin hole36is also shown for clearer illustration of constructional details of the shaft34. In one embodiment, the pin hole36may be cylindrical in shape with a diameter of approximately ⅜ inch, and a length “L7” of approximately ⅜ inch to accommodate the pin60(illustrated inFIGS. 9-10). As noted before, the pin hole36may be drilled into the tube41to allow attachment of the center link26to the shaft34during assembly of the dolly25. Additional assembly details for the dolly25are provided below with reference to discussion ofFIGS. 8-12.

In the side view ofFIG. 7B(which corresponds to the front view depicted inFIG. 7A), the circles illustrated inFIG. 6Care shown along with (i) a circle representing the inner hole (IH) with diameter “D4,” (ii) a circle representing the outer holes (OH1, OH2) with diameter “D3,” and (iii) dotted circles representing the larger and smaller grooves (e.g., the larger side groove47and the smaller end groove53) cut into the tube41. The side view ofFIG. 7Bthus illustrates the axially-offset, hollow, cylindrical geometry of the shaft34in more detail. Although not visible in the side view ofFIG. 7B, it is observed that the pin hole36may be located at a ½ inch clocked position from the top of the shaft34as measured from the central axis passing through all the circles inFIG. 7B.

FIG. 8illustrates how the holes of the shaft34and the center link26may be aligned to attach the center link26to the shaft34. As shown inFIG. 8, a substantially circular pin hole36may be drilled into the middle of the central portion42of the tube41. The top surface in which the pin hole36is drilled may be that surface which is longitudinally substantially aligned with the respective top surfaces of the side portions43,44and the side lobes51,52. Alternately, as illustrated inFIGS. 3 and 8, the pin hole36may be drilled or otherwise formed a distance from the top surface of the central portion42of the tube41. The positional alignment may allow for proper operational orientation of the center link26upon its attachment to the shaft34. The link hole27may be drilled into a circular portion of the center link26that fits over the center portion42of the tube41. The center link26may thus be fitted over the shaft34such that the link hole27is aligned with the pin hole36and the center link26may be attached to the shaft34in a proper orientation by inserting a pin60(illustrated inFIGS. 9-10) through the top of the link hole27into the shaft34via the pin hole36. That pin60may also be metal and may be welded or otherwise secured in place in through the link hole27and pin hole36. In one embodiment, the link hole27is of substantially the same diameter as the pin hole36such that the pin60fully or nearly fully fills both the link hole27and the pin hole36.

In an embodiment, the cylindrical central portion42has a longitudinal portion L (shown onFIG. 6B), a diameter, and first and second ends. A first cylindrical lobe51, having a diameter smaller than the cylindrical central portion42diameter, extends from the first end of the cylindrical central portion42such that an outer surface of the first cylindrical lobe51is flush with an outer surface of the cylindrical central portion42and none of the surfaces of the first cylindrical lobe51extend beyond the surfaces of the cylindrical central portion42. Similarly, a second cylindrical lobe52having a diameter smaller than the cylindrical central portion42diameter and extends from the second end of the cylindrical central portion42such that an outer surface of the second cylindrical lobe52is flush with the outer surface of the cylindrical central portion42that is flush with the outer surface of the first cylindrical lobe51and none of the surfaces of the second cylindrical lobe52extend beyond the surfaces of the cylindrical central portion42. A pin hole36is formed in the cylindrical central portion42substantially centered along the longitudinal portion L (shown onFIG. 6B) of the cylindrical central portion42and at least one-quarter of one inch from the surface of the central cylinder that is flush with the first and second cylindrical lobes51,52. In embodiments, the pin hole36is clocked one-quarter to three-quarters of an inch from the flush surface. The center link26furthermore includes a link hole27and the pin60is disposed through the link hole27and into the pin hole36.

FIGS. 9 and 10provide close-up views of the pin60that attaches the center link26to the shaft34during assembly of the car wash dolly25inFIG. 2. As shown inFIG. 9, in one embodiment, the pin60is also made of steel and is in a cylindrical shape. Upon alignment of the pin hole36and the link hole27, the center link26may be pinned, via pin60, into a clocked position on the shaft34so as to hold the entire dolly25assembly in the desired clocked position for use on the auto-laundry conveyor. Upon attachment of the center link26to the shaft34via the pin60(as shown in the close-up view ofFIG. 10), a correct clocked position can be obtained for the shaft34of the dolly25so as to align the dolly25with a tire resting between two dollies25on an auto-laundry conveyor. The pin60may thus lock the shaft34to the center link26to maintain proper orientation of the shaft34during operation of the dolly25.

In one embodiment, after complete insertion of the pin60through the pin hole36into the link hole26of the shaft34, the pin60is welded to the center link26so as to further strengthen the attachment of the center link26with the shaft34. In one embodiment, the pin60is approximately ⅜ inch in diameter to closely matched to the diameters of the pin hole36and the link hole27, thereby allowing a snug fit between the center link26and the shaft34for the life of the dolly25. In one embodiment, the pin60may be approximately 5/16 inches in length.

FIG. 11shows a partial assembly view depicting placement of a snap ring38and a thrust washer40adjacent to an inner wheel (e.g., the wheel28B) on the shaft34of the car wash dolly25according to one embodiment of the present disclosure. The snap ring38and washer40are also shown inFIG. 3. As is seen fromFIG. 11, in one embodiment, the snap ring38may be “open-ended” in the sense that its two ends38A,38B do not connect. This may allow for easy “snapping” of the ring38into its corresponding groove (here, the groove46shown inFIGS. 4-5). The snap ring38is thus inserted into its corresponding groove after the inner wheel28B is mounted on the shaft34. The thrust washer40may be optionally inserted after the snap ring38, but prior to mounting the intermediate wheel (here, the wheel30B as shown inFIG. 12) on the shaft34. Thus, the washer40may remain inserted between the ring38and the intermediate wheel30B (not shown inFIG. 11, but shown inFIG. 12), thereby reducing friction between the wheels28A and30B during operation of the dolly25. Furthermore, as mentioned before, the grooves and snap rings may “lock” the wheels in their respective places on the shaft34and keep different wheels physically close to one another (while minimizing friction between such closely-spaced adjacent wheels) to minimize or prevent dirt or other debris from lodging between the wheels

Although only one snap ring38is shown inFIG. 11for ease of illustration, it is evident that a total of six snap rings—one in each of the six grooves45,46,47,48,53, and54—may be employed in one embodiment of the present disclosure. The snap rings for the grooves45-48may be substantially identical to the snap ring38shown inFIG. 11. However, because of the smaller diameter of the end grooves53,54, the snap rings (not shown) for those grooves may be smaller in size than the snap rings38for other grooves on the shaft34. Like the shaft34, all of these snap rings also may be made of steel or other suitable hard material to withstand the rigorous operational conditions typically present in an auto-laundry.

The thrust washer40may be made of steel and annular in structure, with its internal diameter substantially similar to the diameter of the corresponding side portion (here, the side portion44inFIG. 11) so as to allow a reasonably snug fit of the washer40on the shaft34while still allowing the washer40to remain rotationally movable around the shaft34. A similar second washer (not shown) also may be mounted between the wheels28A and30A in a similar manner (i.e., after inserting a snap ring after the wheel28A in the groove45, but before mounting the wheel30A on the side portion43). Although not shown inFIG. 11, in one embodiment, a second pair of thrust washers—each similar to the thrust washer40—also may be inserted on opposite sides of the center link26between the center link26and adjacent inner wheels28A,28B. This second pair of thrust washers may be mounted on the shaft34after the center link26is placed on the shaft34, but prior to mounting the wheels28A,28B on the shaft34. In one embodiment, the thrust washers in this second pair may be welded to the center link26to prevent their rotational movement during operation of the dolly25, but still providing an additional friction-reducing surface between the outer sides of the center link26and corresponding adjacent sides of the inner wheels28A,28B.

In one embodiment, no washer may be needed after the snap rings (such as snap ring38A) are placed in grooves47,48because the outer surfaces of corresponding groove boundaries49,50may themselves function as friction-reducing “spacers” between the pairs of adjacent intermediate and outer wheels—i.e., the wheel pairs30A-32A and30B-32B. Similarly, no washer may be needed at the end of the shaft34as well—i.e., after the snap rings (not shown) in grooves53and54.

FIG. 12illustrates a more-detailed partially-assembled view of the dolly25inFIG. 2. InFIG. 12, the center link26is shown mounted on the shaft34along with one set of wheels—i.e., the wheels28B,30B, and32B—mounted on the shaft34on the right side of the center link24in the manner discussed above with reference toFIG. 11. Various snap rings and thrust washers are not visible in the assembled view ofFIG. 12. The other set of wheels—i.e., the wheels28A,30A, and32B—also may be mounted on the left side of the center link26in a similar fashion to fully assemble the dolly25as shown inFIG. 2.

The foregoing describes design of a car wash dolly that uses a single, solid shaft with two camshaft lobes and a series of snap ring grooves. The bolt-less design of the dolly includes a stronger camshaft and minimized component count than prior dollies. The center link and wheels may be mounted directly on the shaft to produce a sturdy design for the dolly. Grooves and snap rings are provided to “lock” wheels in their place on the shaft and to keep wheels physically close to one another to minimize the entry of dirt or other debris between the wheels. Optional thrust washers also may be provided between plastic wheels and snap rings to reduce friction between the wheels during operation of the dolly in a car wash facility. As mentioned earlier, the dolly according to the present disclosure is intended to roll, via a conveyor chain, on a slotted track of a car wash system. It is noted here that although the shaft, snap rings, and thrust washers of the dolly are discussed to have been made of steel, other load-bearing materials (e.g., carbon fiber, different alloys of metals, etc.) also may be used instead of steel for one or more of such components as per relevant design considerations in alternative embodiments. Similarly, wheels made of materials other than plastic may be employed in the dolly to carry out desired functionality during a car wash operation. Furthermore, as mentioned before, various dimensional details provided hereinabove are exemplary in nature, and can be modified as needed without departing from the scope of the teachings in the present disclosure. Also, although the discussion hereinbefore focuses on a car wash facility, the dolly design principles discussed herein may be used to design similar dollies for use in laundry facilities for other types of vehicles or for other purposes.