WO2015031834A1

WO2015031834A1 - Vehicle alignment testing method and apparatus

Info

Publication number: WO2015031834A1
Application number: PCT/US2014/053545
Authority: WO
Inventors: John TAK
Original assignee: International Marketing, Inc.
Priority date: 2013-08-29
Filing date: 2014-08-29
Publication date: 2015-03-05

Abstract

Provided is a method for evaluating the need for alignment of a vehicle. The method comprises providing a vehicle having at least one fixed axle; obtaining a measurement of a wheelbase on a first side of a vehicle, obtaining a measurement of a wheelbase on a second side of the vehicle, comparing the measurement of a wheelbase on a first side of a vehicle with the measurement of a wheelbase on a second side of a vehicle to provide a determination regarding whether said measurements differ by more than a predetermined threshold value, and choosing among a plurality of options for subsequent steps based on said determination.

Description

VEHICLE ALIGNMENT TESTING METHOD AND APPARATUS CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of, and priority to, U.S. Provisional Application No. 61/871,697, filed August 29, 2013, which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

[0002] This application claims the benefit of, and priority to, U.S. Provisional Application No. 61/871,697, filed August 29, 2013, which is hereby incorporated by reference.

Description of Related Art

[0003] The present disclosure relates to vehicles, namely, cars, trucks, buses and other vehicles. More specifically the present disclosure relates to alignment of vehicles having four or more wheels.

[0004] Alignment of the wheels of a vehicle is a standard vehicle maintenance procedure. Poor alignment can undesirably reduce mileage, tire life, and vehicle handling. Alignment generally consists of testing and, if needed, correcting the angles of the wheels of a vehicle. Typical procedures for alignment of a vehicle are complex and expensive. It remains desirable to develop alignment testing methods and apparatuses that reduce complexity and cost as well as methods and apparatuses to evaluate the need for alignment of a vehicle.

SUMMARY OF THE INVENTION

[0005] Particular embodiments of the invention provide a method for evaluating the need for alignment of a vehicle, or, in other words determining whether a vehicle is misaligned. In certain embodiments, the method comprises providing a vehicle having at least one fixed axle, obtaining a measurement of a wheelbase on a first side of a vehicle, obtaining a measurement of a wheelbase on a second side of the vehicle, comparing the measurement of a wheelbase on a first side of a vehicle with the measurement of a wheelbase on a second side of a vehicle to provide a determination regarding whether said measurements differ by more than a predetermined threshold value, and choosing among a plurality of options for subsequent steps based on said determination.

[0006] Certain embodiments of the method comprise ascertaining whether a solid axle of the vehicle and the wheels arranged thereon are square to the longitudinal centerline of the vehicle, that is, in other words, ascertaining whether the rear axle is perpendicular to the vehicle longitudinal centerline. In certain embodiments, the alignment of the front wheels are checked by obtaining a measurement representative of the magnitude of the toe angle of the front wheels.

[0007] In particular embodiments, ascertaining the squareness of the rear axle to the vehicle longitudinal centerline, includes the steps of measuring a first wheelbase distance on a first lateral side of a vehicle, measuring a second wheelbase distance on a second lateral side of a vehicle, and comparing the first wheelbase distance with the second wheelbase distance. If it is determined the first and second wheelbase distances are substantially equal, then it is presumed that the rear axle is substantially perpendicular to the vehicle centerline.

[0008] In other embodiments, before obtaining a measurement representative of the magnitude of the toe angle of the front wheels, the squareness of the solid axle to the centerline of the vehicle is further verified, which includes performing the following steps: measuring a first distance from the first front wheel to the second rear wheel arranged on the opposing lateral side of the vehicle, measuring a second distance from the second front wheel to the first rear wheel arranged on the opposing lateral side of the vehicle, and comparing the first distance with the second distance. If it is determined that the first distance is substantially equal to the second distance, it is presumed that the rear axle is substantially perpendicular to the vehicle centerline, and the toe is subsequently measured as described herein. If it is determined that the first and second distances are not substantially equal, then it is determined that an alignment may be needed.

[0009] In particular embodiments, also provided is a method for evaluating the need for alignment of a vehicle comprising providing a vehicle having at least one fixed axle and having at least four wheels; operationally engaging an alignment apparatus comprising at least four alignment fixtures to the vehicle; obtaining a measurement of a wheelbase on the first side of the vehicle; obtaining a measurement of a wheelbase on the second side of the vehicle; and obtaining measurement representative of the magnitude of the toe angle of one or more of the front wheels. Each alignment fixture is engaged with one of the wheels. The four wheels comprise a front steerable wheel on a first side of the vehicle, a front steerable wheel on a second side of the vehicle laterally opposite the first side, a rear wheel on the first side of the vehicle, and a rear wheel on the second side of the vehicle.

[0010] In another embodiment, also provided is an alignment apparatus for evaluating the need for alignment of a vehicle having at least one fixed axle comprising a first alignment fixture adapted for selectable engagement with a front steerable wheel on a first side of the vehicle; a second alignment fixture adapted for selectable engagement with a front steerable wheel on a second side of the vehicle laterally opposite the first side; a third alignment fixture adapted for selectable engagement with a rear wheel on the first side of the vehicle; and a fourth alignment fixture adapted for selectable engagement with a rear wheel on the second side of the vehicle. The first alignment fixture and the third alignment fixture are adapted to produce a measurement of a wheelbase on the first side of the vehicle by directing a laser therebetween. The second alignment fixture and the fourth alignment fixture are adapted to produce a measurement of a wheelbase on the second side of the vehicle by directing a laser therebetween. The first alignment fixture and the second alignment fixture are adapted to produce a measurement representative of the magnitude of the toe angle of the front steerable wheels by directing a laser therebetween.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Reference is made to the accompanying drawings in which particular embodiments and further benefits of the subject matter are illustrated as described in more detail in the description below, in which:

[0012] FIG. 1A is top view of a representation of a vehicle having a fixed axle, in accordance with an embodiment of the invention.

[0013] FIG. IB is side view of a representation of the vehicle of FIG. 1 A having a fixed axle.

[0014] FIG. 2 is a top view close up of a schematic representation of a first embodiment of an alignment apparatus. [0015] FIG. 3A is a isometric view of a solid model representation of one component of a second embodiment of an alignment apparatus.

[0016] FIG. 3B is a top view of the solid model representation of the component of the second embodiment of an alignment apparatus.

[0017] FIG. 3C is a front view of the solid model representation of the component of the second embodiment of an alignment apparatus.

[0018] FIG. 3D is a isometric view of the solid model representation of the component of the second embodiment of an alignment apparatus operationally engaged with a model of a tire- wheel assembly.

[0019] FIG. 3E is a isometric view of the solid model representation of the component of the second embodiment of an alignment apparatus.

[0020] FIG. 3F is a schematic representation of the component of the tire-wheel assemblies of a vehicle.

[0021] FIG. 3G is a flowchart depicting one embodiment of a method of alignment testing.

[0022] FIG. 3H is a schematic showing one method of taking measurements and communicating the data from the measurements in one embodiment of a method of alignment testing.

[0023] FIG. 4A is a isometric view of a solid model representation of one component of a third embodiment of an alignment apparatus.

[0024] FIG. 4B is an exploded view of the solid model representation of the component of the third embodiment of an alignment apparatus.

[0025] FIG. 4C is an isometric view of a solid model representation of an associated tire wheel assembly engaged with a subset of the third embodiment of an alignment apparatus.

[0026] FIG. 4D is an isometric view of a solid model representation of an associated tire wheel assembly engaged with the third embodiment of an alignment apparatus.

DETAILED DESCRIPTION OF THE INVENTION

[0027] The present subject matter provides a method and apparatus for evaluating the need for alignment of a vehicle having at least one fixed axle. Output from evaluation of the need for alignment of a vehicle having at least one fixed axle may take the form of a Boolean pass or fail result, where pass result indicates no alignment is needed and a fail result indicates an alignment is needed. The present subject matter provides a method and apparatus for adapted for measuring the alignment of a vehicle having at least one fixed axle. Because traditional methods of checking wheel alignments are often time consuming, they are also costly. Accordingly, the present subject matter provides a quick check that will allow a user to more quickly diagnose any problems regarding vehicle performance, such as tire performance, for example, which may display uneven tire wear or tire imbalance or vibration. In quickly checking the need for wheel alignment, a user may gain a better sense of whether the problem is the result of wheel misalignment or of some other vehicle issue, such as wheel vibrations, which may arise due to tire/wheel imbalance or suspension issues. The exemplary embodiments discussed herein may be employed on any vehicle having a fixed axle.

[0028] Referring now to FIGS. 1A and IB, shown is a vehicle 100. Vehicle 100 comprises a frame 110, a fixed axle 120 engaged with frame 110, a first rear wheel 142, a second rear wheel 144, a first front wheel 132, and a second front wheel 134. It is noted that the first front and first rear wheels are arranged on a first lateral side of the vehicle, while the second front and second rear wheels are arranged on a second lateral side of the vehicle, the first lateral side being arranged opposite the second lateral side relative a longitudinal centerline of the vehicle. In the non-limiting embodiment shown, front wheels 132, 134 are steerable, while the rear wheels 142, 144 are non- steerable during vehicle operation.

[0029] In the non-limiting embodiment shown in FIGS. 1A and IB, an alignment apparatus 150 is engaged with the wheels 132, 134, 142, 144 of the vehicle 100. In the embodiment shown, alignment apparatus 150 comprises a first front member 152, a first rear member 162, a second front member 154, and a second rear member 164. It is to be understood that, in lieu of providing all such members 152, 162, 154, 164 at once, in particular embodiments a pair of front and rear members, such as members 152, 162, may be used separately on both pairs of front and rear wheels. In the embodiment shown in FIGS. 1A and IB, each of the first front member 152 and the second front member comprises a laser emitter 172 and a laser receiver 173. Furthermore, each of the first rear member 162 and the second rear member 164 comprises a laser reflector 174. Each laser reflector 174 is adapted to reflect a laser beam 175 emitted from a laser emitter 172, while each laser receiver 173 is adapted to receive and detect a laser beam 175 reflected from laser reflector 174. [0030] It is understood that each laser emitter 172 and receiver 173 may be arranged substantially along the rotational axis of the corresponding front wheel 132, 134 to which each is attached, or a pre-determined offset distance from said rotational axis, while the laser reflector 174 is arranged substantially along the rotational axis of the solid axle 120 or of the rear wheel 142, 144 to which each is attached, or a pre-determined offset distance from either such rotational axis. In particular embodiments, at least one of the laser emitter 172 and receiver 173 is arranged substantially at the intersection of the rotational axis and the steering or pivoting axis of a corresponding front wheel.

[0031] In operation, a processor 210 - either included with the laser receiver or otherwise in communication with the laser receiver - is able to determine the distance between the laser emitter and the laser reflector using known principles. Accordingly, by discharging a laser beam from the laser emitter 172 and capturing the reflected beam from the reflector 174 with the laser receiver 173, each of the first and second front members 152, 154 is adapted to determine a distance between a corresponding laser emitter 172 and laser reflector 174.

[0032] While the distance of the wheelbase 182, 184 between the laser emitter 172 and the laser reflector 174 may comprise a wheelbase distance extending from the rotational axis 176 of the solid axle 120 and to the rotational axis 178, 180 of each front wheel 132, 134, it is understood that the distance measured may be any pre-determined distance, meaning that the laser emitter and the laser reflector may each be aligned along the rotational axis of the solid axle and the front wheel, respectively, or may be offset a known distance therefrom. Therefore, the processor 210 may be configured to output the actual distance measured, or the actual wheelbase after taking into account any offset distance extending between each of the emitter and the reflector from the corresponding front or rear rotational axis.

[0033] In determining whether the rotational axis of the solid axle is substantially perpendicular to the centerline of the vehicle, in particular embodiments, the first measured distance of the wheelbase 182 (that is, the distance between laser emitter 172 and the laser reflector 174 for the first front and rear wheels) is compared to the second measured distance of the wheelbase 184 (that is, the distance between laser emitter 172 and the laser reflector 174 for the second front and rear wheels). The first and second measured distances of the wheelbases 182, 184 are compared to one another. If first and second measured distances of the wheelbase 182, 184 are equal or substantially equal, it may be presumed that the rotational axis of the solid axle, or the rotational axis of each of the rear wheels 142, 144, is perpendicular or substantially perpendicular, respectively, to the longitudinal centerline CL of the vehicle.

[0034] At this juncture, if the measured distances are equal or substantially equal, it may be presumed the rotational axis of the solid axle is at least substantially perpendicular to the centerline of the vehicle. However, in further embodiments, the squareness (that is, the perpendicularity) of the rotational axis to the solid axle may be further evaluated by measuring a distance extending from each of the first and second wheels to the rear wheel on the opposing side of the vehicle, that is, to each of the second and first rear wheels, respectively, and comparing the distances measured. This distances are referred to as first and second cross- distances. It is understood that the same members, or members similar in operation, may be employed, namely, first front member 152, first rear member 162, second front member 154, and a second rear member 164, or each may be modified, such as by using certain attachments or spacers to avoid any features of the vehicle that may otherwise obstruct the laser beam from reaching the reflector arranged across the vehicle (that is, between first front member 152 and second rear member 164, and between second front member 154 and first rear member 162). In lieu of directing laser beams between opposing front and rear wheels, it is appreciated that the laser beams may be directed from one of the wheels in a direction diagonally across the vehicle to a common reflector, such as reflector 192, arranged along the vehicle longitudinal centerline or at a location offset a pre-determined distance between the vehicle centerline and the diagonal wheel (that is, the wheel arranged on the opposing side of the vehicle longitudinal centerline and along the opposing end of the vehicle). For example, as discussed previously, a laser beam may be directed from the first front wheel to a reflector arranged at the second rear wheel to determine a first cross-distance. Or, in lieu thereof, a laser beam may be directed to a reflector located along the vehicle longitudinal centerline, such as at its intersection with the rear axle rotational axis - and any pre-determined distance there from along the vehicle longitudinal centerline (see reflector 192, for example). Still further, the same laser beam may be directed at a first reflector arranged between the longitudinal centerline and the second rear wheel, while a second reflector is arranged between the longitudinal centerline and the first rear wheel to determine a second cross-distance from a laser beam directed from the second front wheel. Nonetheless, if the first and second cross-distances are equal or substantially equal, it is presumed that the rotational axis of the solid axle is perpendicular or substantially perpendicular to the vehicle longitudinal centerline.

[0035] It is appreciated that, in other embodiments, the first and second front members may instead be mounted on the rear wheels, and the first and second rear members may instead be mounted on the front wheels, such that the laser emitters and receivers are instead located on the rear wheels and each laser reflector is instead located on a front wheel.

[0036] Once it has been determined that the solid axle is perpendicular or substantially perpendicular to the vehicle longitudinal centerline, then the toe for any steerable wheel is measured, such as any front wheel as provided in the exemplary embodiment shown. If it is determined that the solid axle is not at least substantially perpendicular to the vehicle longitudinal centerline, then an alignment may be needed.

[0037] In the non-limiting embodiment shown in FIGS. 1A and IB, measurement of toe is performed by discharging a laser beam longitudinally from the laser emitter 172 and capturing the reflected beam from the reflector 174 with the laser receiver 173, determining the longitudinal distance between the corresponding laser emitter 172 and laser reflector 174, and determining the lateral distance along laser receiver 173 from some predefined reference point, a zero angle point, at which the incident laser beam strikes. The arcsine of the ratio of the lateral distance to twice the longitudinal distance is the toe angle. The receiver 173 may have a target 197. The target 197 which may provide visual information about the location of the incident beam along a scale and have identifiers, indicia or markings, arranged along target to permit a user to gauge the lateral distance from some predefined reference point or the target 197 may provide automatic observation or recognition, such as by a laser receiver, etc. from the predefined reference point.

[0038] An imaginary plane of rotation of the first rear wheel 142 will be referred to as plane 185. Plane 185 is normal to the rotational axis 179 of first rear wheel 142 and is assumed to be substantially coincident with the center of axle 120. An imaginary plane of rotation of the second rear wheel 144 will be referred to as plane 186, which is normal to the rotational axis 181 of second rear wheel 144 and is assumed to be substantially coincident with the center of axle 120. An imaginary plane of rotation of the first front wheel 132 will be referred to as plane 187. Plane 187 is normal to the rotational axis 178 of first front wheel 152. An imaginary plane of rotation of the second front wheel 134 will be referred to as plane 188. Plane 188 is normal to the rotational axis 180 about which second front wheel 134 rotates during operation.

[0039] In an alternative embodiment, laser reflector 174 includes a target 198 having a scale to permit a user to gauge the point of incidence of the laser beam 175 thereon relative a reference location along the scale. By using the first front member 152 to determine distance over which the emitted laser 175 travels from the laser emitter 172 to the laser reflector 174 and back to laser receiver 173 and knowing the pre-determined distance from the laser emitter 172 to the point on the laser receiver 173 at which the laser beam 175 is received, a user may substantially define with conventional trigonometry the geometry of the triangle defined by the laser beam 175. Once the geometry of the triangle is known, a user may define with conventional trigonometry the length of wheelbase 182. Also, once the geometry of the triangle defined by the laser beam 175 is known, a user may define with conventional trigonometry the vertical angle between plane 185 and plane 187. This vertical angle between plane 185 and plane 187 is conventionally referred to as the toe angle of the left front wheel and is a useful alignment parameter. The same may be performed and determined for any other steerable wheel.

[0040] In an exemplary embodiment shown in FIG. IB, a horizontal target 194 may be arranged at any distance beneath any steerable wheel (front wheel 134 is shown for example) and a predetermined distance from a known vertical plane, which allows the second front member 154 to project a laser beam therefrom for reception by target 194. The target 194 includes scale identifiers 196, such as indicia or markings, to allow a user to determine the camber relative a reference location. This vertical angle between plane 186 and plane 188 is conventionally referred to as the camber angle of the left front wheel and is a useful alignment parameter. With reference to FIG. 1A, horizontal targets 193 and 194 are shown arranged beneath both first and second front wheels 132, 134, respectively.

[0041] By employing these methods, it is possible to evaluate the necessity of an alignment, to quickly ascertain the perpendicularity of a solid axle, as well as to more quickly ascertaining alignment parameters, such as toe and camber, for example. The alignment parameters may also be compared to intended or desired measurements for each parameter, whether manually or by use of a processor.

[0042] The provided methods allow for evaluating the need for alignment of a vehicle. In one embodiment, a method comprises obtaining a measurement of a wheelbase on a first side of a vehicle, and obtaining a measurement of a wheelbase on a second side of the vehicle, where the measurements are distances. These measurements of the wheelbase are compared to one another and the difference, if any between them is determined. In one embodiment, this difference is compared to a predetermined reference value. In some embodiments, if the difference is greater than or equal to the predetermined reference value, it indicates that the vehicle is sufficiently out of alignment that an alignment should be performed and an alignment may be performed. In some embodiments, if the difference is less than the predetermined reference value, it indicates that the vehicle may be sufficiently aligned such that the next step may be to perform additional evaluation steps or to discontinue evaluation. In other embodiments, the wheelbase measurements for the first and second sides are compared, and if sufficiently different, that is, if not substantially equal, then an alignment may be warranted. In further embodiments, a next step is to perform additional evaluation steps, these additional evaluation steps may include one or more of the step of ascertaining whether a rear axle is perpendicular to a longitudinal centerline of the vehicle, the step of measuring the toe or camber angle of one or more front wheels, other steps. Ascertaining whether a rear axle is perpendicular to a longitudinal centerline of the vehicle may comprise the steps of measuring a first distance from the first front wheel to the second rear wheel arranged on the opposing lateral side of the vehicle; measuring a second distance from the second front wheel to the first rear wheel arranged on the opposing lateral side of the vehicle; and comparing the first distance with the second distance. Measuring the toe or camber angle of one or more front wheels may comprise comparing a measurement obtained by measuring the toe angle of each front wheels to an intended toe or predetermined reference toe or a range of predetermined reference toe angles for each front wheel.

[0043] Referring now to the non-limiting embodiment shown in FIGS. 3A-3E, shown is an alignment fixture 310 adapted for engagement with a tire- wheel assembly. A tire- wheel assembly is a tire operatively mounted on a corresponding wheel adapted for operative use on a wheeled vehicle. An alignment apparatus 300 may consist of a plurality of alignment fixtures 310. The alignment fixtures 310 of the alignment apparatus 300 are adapted for engagement with a vehicle where each alignment fixtures 310 may be operatively engaged with a single tire- wheel assembly 320. In the embodiment shown in FIGS. 3A-3E, the alignment fixtures 310 may each be engaged with a tire-wheel assembly 320 of a vehicle. Without limitation, in certain embodiments, the alignment apparatus 300 may consist or 2, 3, or 4 alignment fixtures 310. In the non-limiting embodiment depicted in the schematic of FIG. 3F, each of the four alignment fixtures 310a, 310b, 310c, 310d shown, is engaged with one of the four tire-wheel assemblies 320a, 320b, 320c, 320d shown. In the embodiment depicted in the schematic of FIG. 3F, the first front wheel 320a and first rear wheel 320d are arranged on a first lateral side of the vehicle, while the second front wheel 320b and second rear wheel 320c are arranged on a second lateral side of the vehicle, the first lateral side being arranged opposite the second lateral side relative a longitudinal centerline of the vehicle. In the non-limiting embodiment shown, front wheels 320a, 320b, are steerable, while the rear wheels 320c, 320d are non-steerable during vehicle operation. It is to be understood that the schematic of FIG. 3F, is non-limiting in the sense that rear wheels 320c, and 320d need not be the only or rear most wheel set of the vehicle; there may be one or more additional sets of wheels behind the rear wheels 320c, 320d.

[0044] In the embodiment shown in FIGS. 3A-3F, the alignment fixtures 310 each comprise a pair of blocks 316 connected by an adjustable mechanism 317. The blocks 316 each define a base surface engagement plane 314 adapted to face against and operationally engage a base surface 94, such as, without limitation, a roadway or garage floor or the like, upon which the footprint of the tire-wheel assembly 320 is disposed during testing as shown in FIG. 3D. The blocks 316 define a sidewall engagement plane 318 adapted to face against and operationally engage a sidewall face or similarly-oriented face of the tire-wheel assembly 320 as shown in FIG. 3D. The blocks 316 each define a tread engagement plane 319 adapted to face against and operationally engage the tread of the tire-wheel assembly 320 as shown in FIG. 3D. Collectively the base surface engagement plane 314, the sidewall engagement plane 318, and the tread engagement planes 319 are adapted to positively locate an alignment fixture 310 with respect to the tire- wheel assembly 320 with which it is operationally engaged. [0045] Adjustable mechanism 317 allows the blocks 316 to be moved with respect to one another such that the alignment fixtures 310 may be clamped onto or otherwise engaged with tire- wheel assembly 320 as shown in FIG. 3D. As shown in non-limiting embodiment in FIGS. 3A-3E, adjustable mechanism 317 may comprise a mechanism, such as a telescopeable slider, scissor linkage, or other linkage. In certain non-limiting embodiments the adjustable mechanism 317 may be adapted to permit the blocks 316 to translate along an axis 315.

[0046] In the embodiment shown in FIGS. 3A-3F, the alignment fixtures 310a, 310b comprises a laser emitter 312 and a laser receiver 313. Furthermore, each of the alignment fixtures 310c, 310d comprises a laser receiver 313. Each laser emitter 312 is adapted to emit a laser beam. In some non-limiting embodiments, a laser emitter 312 may be engaged with additional components to permit a user to selectably guide the direction of the emitted laser beam. In some embodiments, a user may selectably guide the direction of the emitted laser beam by adjusting moving or rotating the laser emitter 312 or by moving or rotating a mirror or prism or other device adapted to reflect, refract, or otherwise redirect the emitted laser beam. As shown in the non-limiting embodiment depicted in FIG. 3F, alignment fixtures 310a may comprise a first laser emitter 312 adapted to emit a laser beam 311a from location 1 and adapted to emit a laser beam 311c from location 1, and a second laser emitter 312 adapted to emit a laser beam 311b from location 2; alignment fixtures 310b may comprise a first laser emitter 312 adapted to emit a laser beam 3 l id from location 3, a first laser receiver 313 adapted to receive laser beam 311a at location 3, and a second laser receiver 313 adapted to receive a laser beam 311b at location 6; alignment fixtures 310c may comprise a laser receiver 313 adapted to receive laser beam 31 Id at location 5; alignment fixtures 310d may comprise a laser receiver 313 adapted to receive laser beam 31 lc at location 4.

[0047] As shown in the non-limiting embodiment depicted in FIG. 3F, in some methods, a user may use an alignment fixture 310a in which the laser emitter 312 is engaged with additional components to permit a user to selectably guide the direction of the emitted laser beam such that a single emitter 312 may emit a beam from location 1 to a receiver 313 at location 4, thereby permitting a laser measurement of the distance from location 1 to location 4, and, at a another time, before or after, the same single emitter 312 may emit a beam from location 1 to a receiver 313 at location 3 thereby permitting a laser measurement of the distance from location 1 to location 3. Using this latter method, two different laser measurements, distance from location 1 to location 4, and distance from location 1 to location 3 are possible using a single laser emitter 312.

[0048] As shown in FIGS. 3D and 3F, in certain non-limiting methods of use fixtures 310a, 310b, 310c, and 310d may each be engaged with a tire wheel assembly 320a , 320b, 320c, and 320d of a vehicle. In the non-limiting embodiment shown in FIG. 3F, the vehicle in question comprises a set of front tire-wheel assemblies 320a, 320b, and a set of rear-ward tire wheel assemblies 320c, 320d. In the non-limiting embodiment shown in FIG. 3F the vehicle has a set of rear-ward tire-wheel assemblies, comprising one or more fixed axles where the front-most set of these rear-ward fixed axles is shown as rear-ward tire wheel assemblies 320c, 320d. In some embodiment, it may be assumed, without the introduction of important error, that these latter fixed axles are substantially immovable with respect to the vehicle for alignment purposes. In the non-limiting embodiment shown in FIG. 3F, fixture 310a is engaged with the driver's side front tire- wheel assembly; fixture 310b is engaged with the passenger's side front tire- wheel assembly; fixture 310c is engaged with a passenger's side rear- ward tire-wheel assembly; fixture 310d is engaged with a driver's side rear- ward tire- wheel assembly. Fixtures 310a, 310b, 310c, and 310d may be used to take four different laser measurements, the distance from location 1 to location 4, the distance from location 1 to location 3, the distance from location 3 to location 5, and the distance from location 2 to location 6 are possible. In the non-limiting embodiment shown in FIG. 3F, the four different laser measurements are taken by emitting laser beam 31 la to obtain the distance from 1 to 3, emitting laser beam 311b to obtain the distance from 2 to 6, emitting laser beam 311c to obtain the distance from 1 to 4, and emitting laser beam 3 l id to obtain the distance from 3 to 5. Once the laser measurements are taken, they are compared. In one comparison, the distance from 1 to 4, the driver's side wheelbase distance, is compared to the distance from 3 to 5, passenger side wheelbase distance, in order to obtain the difference in wheelbase distance across the vehicle. If the difference in wheelbase distance across the vehicle is larger than a predetermined threshold value, then the measurement indicates that alignment of the vehicle to correct the difference in wheelbase distance across the vehicle is needed. In another comparison, the distance from 2 to 6, the front-ward distance between the driver's side and passenger's side front tire-wheel assemblies, is compared to the distance from 1 to 3, the rear-ward distance between the driver's side and passenger's side front tire-wheel assemblies, in order to obtain a measurement representative of the magnitude of the toe angle. If the difference in the front-ward distance between the driver's side and passenger's side front tire-wheel assemblies and the rear-ward distance between the driver's side and passenger's side front tire- wheel assemblies is larger than a predetermined threshold value, then the measurement indicates that alignment of the vehicle to correct the difference in the front-ward distance between the driver's side and passenger's side front tire-wheel assemblies and the rear-ward distance between the driver's side and passenger's side front tire-wheel assemblies is needed. By extension, in some methods if both of the above comparisons yield a difference less than the relevant predetermined threshold value, then alignment of the vehicle is not necessary. Accordingly, by taking the above measurements with the above apparatus, and performing the above comparisons, a user may determine if alignment of the vehicle is needed. An exemplary embodiment of the method is shown in FIG. 3G by way of flowchart 370. In another exemplary embodiment of the method, as diagrammed in FIG. 3H by way of diagram 380, communication between the alignment fixtures 310 may be by Bluetooth as shown by the arrows 382, in addition to any other means as contemplated herein or as maybe known to one of ordinary skill.

[0049] Referring now to the non-limiting embodiment shown in FIGS. 4A-4D, shown is an alignment fixture 410 adapted for engagement with a tire- wheel assembly 420. A tire- wheel assembly 420 is a tire 424 as mounted on a corresponding wheel 426 for operative use on a wheeled vehicle. An alignment apparatus may consist of a plurality of alignment fixtures 410. The alignment fixtures 410 of the alignment apparatus are adapted for engagement with a vehicle where each alignment fixtures 410 may be operatively engaged with a single tire- wheel assembly 420. In the embodiment shown in FIGS. 4A-4D, the alignment fixtures 410 may each be engaged with a tire-wheel assembly 420 of a vehicle. Without limitation, in certain embodiments, the alignment apparatus may consist or 2, 3, or 4 alignment fixtures 410.

[0050] Similarly to the non-limiting embodiment depicted in the schematic of FIG. 3F, each of the four alignment fixtures 410, may be engaged with one of the four tire-wheel assemblies 420. Similarly to the non-limiting embodiment depicted in the schematic of FIG. 3F, the first front wheel and first rear wheel are arranged on a first lateral side of the vehicle, while the second front wheel and second rear wheel are arranged on a second lateral side of the vehicle, the first lateral side being arranged opposite the second lateral side relative a longitudinal centerline of the vehicle where the front wheels are steerable, while the rear wheels are non-steerable during vehicle operation.

[0051] In the embodiment shown in FIGS. 4A-4D, the alignment fixtures 410 each comprise a set of lug nut caps 411, a set of mounting legs 412, a support plate 415, a toe arm 416, and a housing 417. The lug nut caps are provide engagement with the wheel 426 and are adapted for engagement with the lug nuts (not shown) of a wheel 426. The mounting legs 412 are elongated structures each having a first end 413 engaged with a lug nut cap 411 proximate to an associated wheel 426 and extending from the lug nut cap 411 to provide clearance from the associated wheel 426 for a second end 414. Support plate 415 engages each of the second ends 414 of each of the mounting legs 412 and provides a structure which connects them. To the support plate 415 may be engaged with the toe arm 416 by a rod or pin 415a that locates the engagement which still permitting rotational freedom about the axis of the rod or pin 415a. This same rotational freedom can be selectably controlled by use with a friction fit or a set screw or both. By permitting selectably controllable rotational freedom about the axis of the rod or pin 415a, the components engaged with rod or pin 415a may be leveled, oriented, or adjusted with respect to one another or otherwise as a user desires. The toe arm 416 is an elongated structure that extends from a first end 416a proximate to the support plate 415 and extends to a second end 416b distal from the support plate. Proximate to the second end 416b of the toe arm 416 is engaged a laser distance measurer 417. The toe arm 416 is long enough and shaped such that the laser distance measurer 417 engaged therewith has clearance around tire 424 such that the laser distance measurer 417 has a clear line of sight pas the tire. As shown in the embodiment depicted in FIG. 4D, each laser distance measurer 417 is held out from tire 424 such that each laser distance measurer 417 has a clear line of sight in the lateral direction 492 across the centerline of the associated vehicle. A reflector 418 or another laser distance measurer 417 may also or alternatively be engaged with the support plate 415 to provide a laser measurement in the longitudinal direction 494.

[0052] In the embodiment shown in FIGS. 4A-4D the alignment fixtures 410 comprise one or more laser distance measurers 417. Each laser distance measurer 417 is adapted to emit a laser beam. As shown in the non-limiting embodiment depicted in FIGS. 4A-4D, in some methods, a user may use an alignment fixture 410 with which two laser distance measurer 417 are engaged to emit laser beams along direction 492 both in front of and behind the tire 424 and across the latitudinal direction of the vehicle to a similar alignment fixture 410 engaged with the tire on the opposite side of the vehicle and, by comparing the measurements, get a measurement representative of the toe of the vehicle. If the toe is larger than a predetermined threshold value, then the measurement indicates that alignment of the vehicle to correct the toe is needed.

[0053] Similarly, in some methods, a user may use an alignment fixture 410 with which a laser distance measurer 417 is engaged to emit a laser beam along direction 494 along the vehicle and either from or to a reflector or another laser distance measurer 417 engaged with a tire wheel assembly engaged with a fixed axle so as to get a measurement of the wheelbase distance on one side of the vehicle. By taking a similar measurement on the opposite side of the vehicle and comparing the wheelbase distance on one side of the vehicle with the wheelbase distance on opposite side of the vehicle, get a measurement representative of the difference of the wheelbase distance across the vehicle. If the difference in wheelbase distance across the vehicle is larger than a predetermined threshold value, then the measurement indicates that alignment of the vehicle to correct the difference in wheelbase distance across the vehicle is needed.

[0054] The above instruments and measurement devices may communicate with one another or with a controller or a computer by cabling, wiring, wireless communications system, or other conventional means, such as but not limited to radio, infrared, Bluetooth, Ethernet, or Wi-Fi.

[0055] With respect to a particular vehicle or model of vehicle it may be possible to set up a vehicle having known to have very good alignment and to use the above described methods or apparatuses to obtain reference alignment measurements against which subsequent alignment measurements may be compared, These reference alignment measurements or a subset thereof may be useful in establishing, or predetermining, reference values. Established reference values may be used as a basis for comparison such that subsequent measurements may be compared to the established reference values, and the magnitude of the difference, if any, used to guide choosing among a plurality of options for subsequent steps. Established reference values may be used as a basis for comparison such that subsequent measurements may be compared to the established reference values, and the magnitude of the difference, if any, may be compared to a threshold value where if the magnitude of the difference is greater than the threshold value, the vehicle fails the alignment check such that alignment is needed and if the magnitude of the difference is equal to or less than the threshold value, the vehicle passes the alignment check such that an alignment is not needed.

[0056] It will be appreciated by those of reasonable skill in the art, that various modifications can be made, and that many changes can be made to the exemplary embodiments without departing from the principles of the present subject matter. These and other modifications in the nature of the present subject matter or the provided embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the present subject matter and not as a limitation.

Claims

CLAIMS What is claimed is:

1. A method for evaluating the need for alignment of a vehicle comprising:

providing a vehicle having at least one fixed axle;

obtaining a measurement of a wheelbase on a first side of a vehicle;

obtaining a measurement of a wheelbase on a second side of the vehicle; and

comparing the measurement of a wheelbase on a first side of a vehicle with the measurement of a wheelbase on a second side of a vehicle to provide a determination regarding whether said measurements differ by more than a predetermined threshold value; and

choosing among a plurality of options for subsequent steps based on said determination.

2. The method of claim 1 wherein said determination is a Boolean pass or fail.

3. The method of claim 2 wherein said plurality of options for subsequent steps comprises an option for performing an alignment.

4. The method of claim 3 wherein said plurality of options for subsequent steps comprises at least one option for performing additional evaluation steps.

5. The method of claim 4, wherein said at least one option for performing additional evaluation steps comprises ascertaining whether a rear axle is perpendicular to a longitudinal centerline of the vehicle.

6. The method of claim 5, wherein ascertaining whether a rear axle is perpendicular to longitudinal centerline of the vehicle comprises the steps of,

measuring a first distance from a first front wheel to a second rear wheel arranged on the opposing lateral side of the vehicle;

measuring a second distance from a second front wheel to a first rear wheel arranged on the opposing lateral side of the vehicle; and comparing the first distance with the second distance.

7. The method of claim 6, further comprising comparing a measurement representative of magnitude of toe angle of the front wheels to a threshold value.

8. The method of claim 4, wherein said at least one option for performing additional evaluation steps comprises performing an alignment.

9. A method for evaluating need for alignment of a vehicle comprising:

providing a vehicle having at least one fixed axle and having at least four wheels;

operationally engaging an alignment apparatus comprising at least four alignment fixtures to the vehicle,

wherein each alignment fixture is engaged with one of the four wheels; and wherein the four wheels comprise,

a front steerable wheel on a first side of the vehicle, a front steerable wheel on a second side of the vehicle laterally opposite the first side,

a rear wheel on the first side of the vehicle,

a rear wheel on the second side of the vehicle;

obtaining a measurement of a wheelbase on the first side of the vehicle;

obtaining a measurement of a wheelbase on the second side of the vehicle; and obtaining measurement representative of magnitude of toe angle of the front wheels.

10. The method of claim 9, wherein obtaining a measurement of a wheelbase on the first side of the vehicle comprises a measurement made by emitting a laser between

the alignment fixture engaged with the front steerable wheel on the first side of the vehicle; and

the alignment fixture engaged with the rear wheel on the first side of the vehicle.

11. The method of claim 10, wherein obtaining a measurement of a wheelbase on the second side of the vehicle comprises a measurement made by emitting a laser between

the alignment fixture engaged with the front steerable wheel on the second side of the vehicle; and

the alignment fixture engaged with the rear wheel on the second side of the vehicle.

12. The method of claim 11, wherein obtaining a measurement representative of the magnitude of the toe angle of the front wheels comprises a measurement made by emitting a first laser between

the alignment fixture engaged with the front steerable wheel on the second side of the vehicle..

13. The method of claim 12, wherein obtaining a measurement representative of the magnitude of the toe angle of the front wheels comprises a measurement made by emitting a second laser between

the alignment fixture engaged with the front steerable wheel on the second side of the vehicle.

14. The method of claim 13, wherein the first laser is emitted along a path in front of the front steerable wheel on the first side of the vehicle and in front of the front steerable wheel on the second side of the vehicle.

15. The method of claim 14, wherein the second laser is emitted along a path to the rear of the front steerable wheel on the first side of the vehicle and to the rear of the front steerable wheel on the second side of the vehicle. An alignment apparatus for evaluating the need for alignment of a vehicle having at least fixed axle comprising:

a first alignment fixture adapted for selectable engagement with a front steerable wheel on a first side of the vehicle;

a second alignment fixture adapted for selectable engagement with a front steerable wheel on a second side of the vehicle laterally opposite the first side;

a third alignment fixture adapted for selectable engagement with a rear wheel on the first side of the vehicle; and

a fourth alignment fixture adapted for selectable engagement with a rear wheel on the second side of the vehicle;

wherein the first alignment fixture and the third alignment fixture are adapted to produce a measurement of a wheelbase on the first side of the vehicle by directing a laser therebetween;

wherein the second alignment fixture and the fourth alignment fixture are adapted to produce a measurement of a wheelbase on the second side of the vehicle by directing a laser therebetween; and

wherein the first alignment fixture and the second alignment fixture are adapted to produce a measurement representative of the magnitude of the toe angle of the front steerable wheels by directing a laser therebetween.