Wheel alignment system
DC CAFCFirst Claim
1. A wheel alignment system for measuring alignment angles of wheels which support a vehicle on a running surface, comprisingsystem function control means for providing system operating instructions and for receiving alignment angle data,angle sensing means mounted on at least two of the vehicle support wheels for providing angle measurement signals indicative of the angle between the planes of the support wheels and a reference direction,said angle sensing means further comprising fast response signal amplitude sampling means for providing substantially instantaneous toe angle measurement signal detection, whereby data update frequency is increased and angle sensing accuracy is improved,sensor and system interface control means for receiving and preprocessing said angle measurement signals and external system control inputs and for providing bi-directional data flow between said angle sensing means and said system function control means, andgraphics array control and display means for receiving and displaying measured alignment angle data.
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Abstract
The disclosure herein relates to an alignment system and method which provides improved accuracy measurement of vehicle wheel alignment characteristics, guidance for an operator through known yet obscure adjustment procedures, an interface between system alignment sensors and the system controller which provides efficient handling of system generated data and system inputs and outputs, and live measurements and display of all alignment quantities so that interdependent changes between adjustable alignment quantities are observable.
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Citations
36 Claims
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1. A wheel alignment system for measuring alignment angles of wheels which support a vehicle on a running surface, comprising
system function control means for providing system operating instructions and for receiving alignment angle data, angle sensing means mounted on at least two of the vehicle support wheels for providing angle measurement signals indicative of the angle between the planes of the support wheels and a reference direction, said angle sensing means further comprising fast response signal amplitude sampling means for providing substantially instantaneous toe angle measurement signal detection, whereby data update frequency is increased and angle sensing accuracy is improved, sensor and system interface control means for receiving and preprocessing said angle measurement signals and external system control inputs and for providing bi-directional data flow between said angle sensing means and said system function control means, and graphics array control and display means for receiving and displaying measured alignment angle data.
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2. A wheel alignment system for measuring alignment angles of wheels which support a vehicle on a running surface, comprising
system function control means for providing system operating instructions and for receiving alignment angle data, angle sensing means mounted on at least two of the vehicle support wheels for providing angle measurement signals indicative of the angle between the planes of the support wheels and a reference direction, said angle sensing means further comprising improved response toe angle sensing means for providing substantially instantaneous angle measurement signal detection, whereby data update frequency is increased and angle sensing accuracy is improved, sensor and system interface control means for receiving said angle measurement signals and external system control inputs and for providing bi-directional data flow between said angle sensing means and said system function control means, and graphics array control and display means for receiving and displaying measured alignment angle data, wherein said angle sensing means comprises means for projecting a plurality of light beams having a predetermined carrier frequency at known successive time intervals and in known orientation relative to the plane of one of the at least two support wheels, light beam receiving means mounted in known orientation relative to the plane of the other one of the at least two support wheels and in the path of the plurality of light beams, whereby an angle signal output is provided upon reception of ones of said plurality of light beams, high pass filter means connected to receive said angle signal output, said high pass filter having a pass band substantially above ambient light noise frequencies and including said carrier frequency whereby said angle output signal is passed substantially noise free, means for detecting said substantially noise free angle output signal and for storing a signal indicative of the amplitude thereof, and control means for receiving said stored signal indicative of amplitude an for erasing said stored signal before the next successive projected light beam is sensed by said light beam receiving means.
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6. A toe angle signal sensing system for detecting toe angle of a wheel pair supporting a vehicle for running on an underlying surface, wherein a plurality of light beams having a predetermined carrier frequency are projected at known successive times and at known angles to the plane of one of the wheel pair, and a light beam receiver is mounted in known position and in the path of the plurality of light beams and producing an angle signal output indicative of reception of ones of the light beams, comprising
high pass filter means connected to receive said angle signal output and having a pass band substantially above ambient light noise frequencies and including the carrier frequency for providing a high pass output relating to said angle signal output, means for detecting said high pass output and for storing a signal indicative of the amplitude thereof, and control means for receiving and for erasing said stored signal indicative of amplitude before the next successive light beam is sensed by the light beam receiver.
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11. A method of adjusting the rolling direction of a pair of wheels to a predetermined angle, wherein the wheels are connected by a solid axle supported by a pair of spaced spring assemblies attached to the axle by shackles extending through holes in a pair of shackle plates, comprising the steps of
measuring the wheel rolling direction angle, calculating an adjustment angle between the measured wheel rolling direction and the predetermined wheel rolling direction, measuring the distance between the spaced spring assemblies, and computing an elongation dimension and direction for the holes in the shackle plate as the product of the distance and the sine of the adjustment angle.
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13. A method for simultaneously adjusting camber and caster of a wheel on a vehicle to a specified value, wherein the wheel assembly is pivotally carried on the vehicle by a member having a particular geometry which is attached to the vehicle body at forward and rear adjustable attachment points, and wherein measurement instruments provide wheel caster and camber measurements, comprising the steps of
initially adjusting the position of one of the forward and rear adjustable attachment points, sensing the effect of the step of initially adjusting on camber and caster measurement, predicting the effect of subsequent adjustment at the other of the forward and rear adjustable attachment points by using the effect from the sensing step, and calculating the adjustments at each of the forward and rear adjustable attachment points to obtain the specified values of wheel caster and camber for any particular geometry of the member which pivotally carries the wheel.
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18. A method of adjusting alignment of a laterally disposed pair of independent suspended wheels on a vehicle, wherein the wheels have alignment measurement instruments in communication therewith for measuring wheel alignment characteristics of the pair of wheels and wherein the wheels are carried by support structure connected together by a rigid member extending therebetween, comprising the steps of
measuring the camber and steering axis inclination alignment characteristics for each of the pair of wheels, comparing the measured alignment characteristics for each wheel of the pair for indication of lateral shift of the rigid member, and adjusting the lateral position of the rigid member in the direction which moves steering axis inclination and camber measurements on both of the pair of wheels toward specification values if indication exists that the rigid member has shifted.
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19. A method of adjusting steering axis inclination, included angle and camber of a wheel suspended from and supporting a vehicle for running on an underlying surface while the wheel is raised above the underlying surface, wherein alignment measurement instruments are coupled to the wheel for providing alignment angle output, and wherein brakes are locked and the alignment measurement instruments are locked to prevent rotation relative to the wheel during known portions of the process, comprising the steps of
steering the wheel straight ahead, storing the camber measurement output while the vehicle is set down on the underlying surface, raising the vehicle above the underlying surface, measuring the camber output when the vehicle is raised, calculating the difference between the camber outputs with the vehicle lowered and raised, steering the wheel through a known angle in a left direction, storing the steering axis inclination alignment angle left turn output, steering the wheel through a known angle in a right direction, storing the steering axis inclination angle right turn output, calculating the steering axis inclination angle from the left and right turn outputs, calculating a modified steering axis inclination angle output using the difference between camber outputs lowered and raised, storing the modified steering axis inclination angle output, and adjusting camber and steering axis inclination outputs in the raised condition using the stored modified steering axis inclination output and the stored camber measurement output obtained when the wheel was set down.
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32. An alignment system display for showing alignment characteristics of wheels on a vehicle, comprising
a graphics array control means, and means for providing a live display of all quantities being aligned connected to said graphics array control means, whereby all current changes in quantities relating to alignment characteristics caused by alignment adjustment are displayed.
Specification