On the fly run-out correction for vehicle alignment

Claim 1

Apparatus for correcting for test instrument run-out in a vehicle wheel alignment system of the type wherein a fixture is detachably mounted on a wheel, said fixture including sensor means for detecting the angular inclination of said fixture during rotation of said wheel, and signal means responsive to said sensor means for providing signals proportional to the angular inclination of said fixture in a selected alignment plane; the improvement wherein said sensor means continuously provides fixture inclination signals during rotation of said wheel through at least 360° from any random starting position to any stopped position, means for continuously receiving said continuous inclination signals, maximum and minimum signal comparator devices and maximum and minimum signal storage devices respectively connected to said comparator devices, said means for receiving said inclination signals from said sensor means continuously presenting said inclination signals to said storage devices, said comparator devices having means for selectively providing load signals to their respective storage devices for admitting said inclination signals thereto, said maximum and minimum comparator devices providing said load signals only when said inclination signals are respectively greater than and lesser than the signals received from their associated signal storage devices thereby obtaining and storing the maximum and minimum angular fixture inclination signals in said alignment plane relative to a selected reference plane, first adder means for taking half the sum of said maximum and minimum angular fixture inclination signals to provide a first signal proportional to the actual angular inclination of said wheel in a selected alignment plane, means for coupling said maximum and minimum signals to said first adder means, and means for receiving an intermediate inclination signal from said sensor means when said wheel reaches any random stopped position and for receiving said first signal, said last named means operating to combine said first and intermediate signals and to provide a run-out error signal proportional to fixture run-out at said random stopped position.

Claim 6

The method of determining test instrument run-out error of vehicle wheels wherein the wheel under test is first raised from the ground and a test instrument is installed thereon, said test instrument comprising a fixture that is detachably mounted on said wheel, said test instrument also comprising a sensor support member that is rotatably mounted on said fixture about an axis that is determined by the mounted position of the fixture, said sensor support member being gravity stabilized as the wheel and fixture are rotated about the wheel axis, sensor means on said stabilized support member for detecting the angular inclination of said fixture axis during said wheel rotation, and signal means responsive to said sensor means for providing signals proportional to the angular inclination of said fixture axis in a selected alignment plane; the improvement comprising the steps of rotating said wheel at least 360° from any random starting position and thereafter stopping wheel rotation at any stopped position, continuously providing fixture axis inclination signals from said signal means during said wheel rotation, obtaining from said inclination signals the maximum and minimum angular fixture axis inclination signals in said selected plane relative to a selected reference plane, taking half the sum of said maximum and minimum angular fixture axis inclination signals to provide a preliminary inclination signal proportional to the actual angular inclination of said wheel axis in said alignment plane, obtaining an intermediate inclination signal from said sensor means and signal means proportional to the angular inclination of said fixture axis in said selected alignment plane at said wheel stopped position, taking the difference between said intermediate inclination signal and said preliminary inclination signal to provide a run-out error signal proportional to that portion of the maximum angular run-out of said fixture axis in said alignment plane that is present at said wheel stopped position with said wheel raised, storing said run-out error signal, lowering said wheel to the ground while the wheel remains at said stopped position, obtaining a final fixture axis inclination signal from said sensor means in said selected alignment plane when the wheel is lowered, and subtracting said run-out error signal from said final inclination signal to provide a corrected alignment signal that represents the true wheel axis inclination in said selected alignment plane, corrected for run-out error.

Claim 7

The method of determining test instrument run-out error of vehicle wheels wherein the wheel under test is first raised from the ground and a test instrument is installed thereon, said test instrument comprising a fixture that is detachably mounted on said wheel, said test instrument also comprising a sensor support member that is rotatably mounted on said fixture about an axis that is determined by the mounted position of the fixture, said sensor support member being gravity stabilized as the wheel and fixture are rotated about the wheel axis, sensor means on said stabilized support member for detecting the angular inclination of said fixture axis during said wheel rotation, and signal means responsive to said sensor means for providing signals proportional to the angular inclination of said fixture axis in a selected alignment plane; the improvement comprising the steps of rotating said wheel at least 360° from any random starting position and thereafter stopping wheel rotation at any stopped position, continuously providing fixture axis inclination signals from said signal means during said wheel rotation, obtaining from said inclination signals the maximum and minimum angular fixture axis inclination signals in said selected plane relative to a selected reference plane, taking half the sum of said maximum and minimum angular fixture axis inclination signals to provide a preliminary inclination signal proportional to the actual angular inclination of said wheel axis in said alignment plane, obtaining an intermediate inclination signal from said sensor means and signal means proportional to the angular inclination of said fixture axis in said selected alignment plane at said wheel stopped position, taking the difference between said intermediate inclination signal and said preliminary inclination signal to provide a run-out error signal proportional to that portion of the maximum angular run-out of said fixture axis in said alignment plane that is present at said wheel stopped position with said wheel raised, storing said run-out error signal, lowering said wheel to the ground while the wheel remains at said stopped position, obtaining a final fixture axis inclination signal from said sensor means in said selected alignment plane when the wheel is lowered, and subtracting said run-out error signal from said final inclination signal to provide a corrected alignment signal that represents the true wheel axis inclination in said selected alignment plane, corrected for run-out error.

Claim 12

The method of determining test instrument run-out error of vehicle wheels wherein the wheel under test is raised from the ground and a test instrument is installed thereon, said test instrument comprising a fixture that is detachably mounted on said wheel, said test instrument also comprising a sensor support member that is rotatably mounted on said fixture about an axis that is determined by the mounted position of the fixture, said sensor support member being gravity stabilized as the wheel and fixture are freely rotated about the wheel axis, sensor means on said stabilized support member for detecting the angular inclination of said fixture axis during said wheel rotation, and signal means responsive to said sensor means for providing signals proportional to the angular inclination of said fixture axis in a selected alignment plane; the improvement comprising the steps of elevating the wheel to free the wheel from the ground, rotating said wheel at least 360° from any random starting position and thereafter stopping wheel rotation at any stopped position, continuously providing fixture axis inclination signals from said signal means during said wheel rotation, obtaining from said continuously received inclination signals the maximum and minimum angular fixture axis inclination signals in said selection plane relative to a selected reference plane, taking half the sum of said maximum and minimum angular fixture axis inclination signals to provide a preliminary inclination signal proportional to the actual angular inclination of said wheel axis in said alignment plane, obtaining an intermediate inclination signal from said sensor means and signal means proportional to the angular inclination of said fixture axis in said selected alignment plane at said wheel stopped position and taking the difference between said intermediate inclination signal and said preliminary inclination signal to provide a run-out error signal that is proportional to that portion of the maximum angular run-out of said fixture axis in said alignment plane that exists at said wheel stopped position.

Claim 13

The method of determining test instrument run-out error of vehicle wheels wherein the wheel under test is raised from the ground and a test instrument is installed thereon, said test instrument comprising a fixture that is detachably mounted on said wheel, said test instrument also comprising a sensor support member that is rotatably mounted on said fixture about an axis that is determined by the mounted position of the fixture, said sensor support member being gravity stabilized as the wheel and fixture are freely rotated about the wheel axis, sensor means on said stabilized support member for detecting the angular inclination of said fixture axis during said wheel rotation, and signal means responsive to said sensor means for providing signals proportional to the angular inclination of said fixture axis in a selected alignment plane; the improvement comprising the steps of elevating the wheel to free the wheel from the ground, rotating said wheel at least 360° from any random starting position and thereafter stopping wheel rotation at any stopped position, continuously providing fixture axis inclination signals from said signal means during said wheel rotation, obtaining from said continuously received inclination signals the maximum and minimum angular fixture axis inclination signals in said selection plane relative to a selected reference plane, taking half the sum of said maximum and minimum angular fixture axis inclination signals to provide a preliminary inclination signal proportional to the actual angular inclination of said wheel axis in said alignment plane, obtaining an intermediate inclination signal from said sensor means and signal means proportional to the angular inclination of said fixture axis in said selected alignment plane at said wheel stopped position and taking the difference between said intermediate inclination signal and said preliminary inclination signal to provide a run-out error signal that is proportional to that portion of the maximum angular run-out of said fixture axis in said alignment plane that exists at said wheel stopped position.

Claim 17

The method of correcting for test instrument run-out error of vehicle wheels wherein a test instrument is installed on the wheel under test, said test instrument comprising a fixture that is detachably mounted on said wheel, sensor means on said fixture for detecting the angular inclination of said fixture during rotation of said wheel, signal means responsive to said sensor means for providing signals proportional to the angular inclination of said fixture in a selected alignment plane, and circuit means coupled to receive said signals and including maximum and minimum storage devices; the improvement comprising the steps of rotating said wheel at least 360° from any random starting position and thereafter stopping wheel rotation, continuously providing fixture inclination signals from said signal means during said wheel rotation, continuously comparing, during said wheel rotation, the present inclination signal with the previous inclination signals from said maximum and minimum signal storage devices, admitting the present inclination signal to said maximum signal storage device only when the present inclination signal is greater than that previously stored in said maximum signal storage device, and admitting the present inclination signal to said minimum signal storage device only when the present inclination signal is less than that previously stored in said minimum signal storage, thereby obtaining from said continuously provided inclination signals the maximum and minimum angular fixture inclination signals in said alignment plane relative to a selected reference plane, taking half the sum of said maximum and minimum angular fixture inclination signals to provide an inclination signal proportional to the actual angular inclination of said wheel in said selected alignment plane stopping the wheel at any random rotational position and sensing the stopped wheel fixture inclination, and combining the actual angular inclination signal with the stopped wheel fixture inclination to provide a run-out error signal indicative of the portion of maximum angular fixture run-out existing at the random stopped position.

Claim 18

The method of correcting for test instrument run-out error of vehicle wheels wherein a test instrument is installed on the wheel under test, said test instrument comprising a fixture that is detachably mounted on said wheel, sensor means on said fixture for detecting the angular inclination of said fixture during rotation of said wheel, signal means responsive to said sensor means for providing signals proportional to the angular inclination of said fixture in a selected alignment plane, and circuit means coupled to receive said signals and including maximum and minimum storage devices; the improvement comprising the steps of rotating said wheel at least 360° from any random starting position and thereafter stopping wheel rotation, continuously providing fixture inclination signals from said signal means during said wheel rotation, continuously comparing, during said wheel rotation, the present inclination signal with the previous inclination signals from said maximum and minimum signal storage devices, admitting the present inclination signal to said maximum signal storage device only when the present inclination signal is greater than that previously stored in said maximum signal storage device, and admitting the present inclination signal to said minimum signal storage device only when the present inclination signal is less than that previously stored in said minimum signal storage, thereby obtaining from said continuously provided inclination signals the maximum and minimum angular fixture inclination signals in said alignment plane relative to a selected reference plane, taking half the sum of said maximum and minimum angular fixture inclination signals to provide an inclination signal proportional to the actual angular inclination of said wheel in said selected alignment plane stopping the wheel at any random rotational position and sensing the stopped wheel fixture inclination, and combining the actual angular inclination signal with the stopped wheel fixture inclination to provide a run-out error signal indicative of the portion of maximum angular fixture run-out existing at the random stopped position.