Automobile wheel alignment device and method

An apparatus for measuring the position of wheels on a vehicle comprising:

• a head unit;
• means for detachably and adjustably mounting the head unit on a front wheel;
• adjustable projecting means connectable to a power source and carried by the head unit for selectively projecting a first beam across the front of a vehicle to measure front wheel toe and for selectively projecting a second beam to the axially adjacent rear wheel to determine rear wheel position;
• beam receiving means;
• means for detachably mounting beam receiving means on the front wheel opposite the head unit and the rear wheel axially adjacent the head unit;
• and computation means coupled to the head unit for determining the amount of toe in a front wheel in relation to a vehicle thrust-line reference calculated from the positions of the rear wheels of the vehicle.

An apparatus for measuring the toe relationship of wheels on a vehicle with respect to a calculated thrust-line reference comprising:

• a head unit;
• means for detachably and adjustably mounting the head unit on a front wheel;
• adjustable projecting means connectable to a power source and carried by the head unit for selectively projecting a first beam across the front of a vehicle to measure front wheel toe and for selectively projecting a second beam to the axially adjacent rear wheel to determine rear wheel position;
• beam receiving means;
• means for detachably mounting beam receiving means on the front wheel opposite the head unit and the rear wheel axially adjacent the head unit;
• and meter means coupled to computation means on the head unit for calculating a vehicle thrust-line reference determined from the positions of the rear wheels of the vehicle and visually indicating the amount of toe in a front wheel in relation to the vehicle thrust-line reference.

A head unit for measuring vehicle wheel toe comprising:

• a base member;
• means for removably mounting the base member upon a vehicle wheel;
• means for orienting the base member along a predetermined axis relative to the wheel upon which it is mounted;
• means for maintaining the orientation of the base member on a predetermined axis;
• a light source carried by the base member;
• means connected to the light source for selective energization thereof and for coupling to a power source;
• light projecting means carried by the base member and disposed relative to the light source for transmission of a light beam on a predetermined optical axis;
• means for rotating the light projecting means relative to the base on an axis substantially normal to the optical axis;
• and wherein signal generating means connectable to a power source are carried by the base for generating signal values proportional to the rotation of the light projecting means relative to the base and means are provided for coupling the signal generating means to an indicator means for the transmission of signals thereto.

A head unit for measuring vehicle wheel toe comprising:

• a base member;
• means for removably mounting the base member upon a vehicle wheel;
• means for orienting the base member along a predetermined axis relatve to the wheel upon which it is mounted;
• means for maintaining the orientation of the base member on a predetermined axis;
• a light source carried by the base member;
• means connected to the light source for selective energization thereof and for coupling to a power source;
• light projecting means carried by the base member and disposed relative to the light source for transmission of a light beam on a predetermined optical axis;
• means for rotating the light projecting means relative to the base on an axis substantially normal to the optical axis;
• and wherein signal generating means connectable to a power source are carried by the base and means are provided for coupling the signal generating means to a computation means.

A method for producing predetermined toe angles of vehicle wheels comprising:

• determining the position of the rear wheels;
• measuring the position of each rear wheel of a vehicle;
• combining the positions of both rear wheels to determine the total toe of the rear wheels;
• computing the thrust-line of the vehicle determined by the position and combined toe angles of the rear vehicle wheels;
• measuring the toe angle of each front wheel of a vehicle in relation to the computed thrust-line of the vehicle;
• and adjusting the measured toe angle of each front wheel to a predetermined angular relationship with the computed thrust-line of the vehicle whereby the front wheel toe is set at a predetermined angle to the computed thrust-line of the vehicle.

A method for setting front vehicle wheel toe angles and maintaining a centered steering wheel comprising the steps of:

• centering the steering wheel;
• measuring a first toe angle of the left and right front vehicle wheels;
• measuring a second tow angle of the left and right rear vehicle wheels;
• determining the position of the rear wheels;
• calculating a center of thrust-line reference of the rear vehicle wheels from the position of the second toe angle of the left and right rear vehicle wheels referenced to the respective first toe angle of the left and right front vehicle wheels;
• calculating a third toe angle of the left and right vehicle wheels from the second toe angle and position of the left and right rear vehicle wheels in relationship to the center of thrust-line reference;
• and setting the third toe angle into the left and right front vehicle wheels in relationship to the thrust-line reference.

A method for centering the steering wheel and setting front toe angles of vehicle wheels comprising the steps of:

• centering the steering wheel of the vehicle;
• measuring a toe angle of the left and right front vehicle wheels with respect to a reference fixed at a predetermined distance from the opposite front vehicle wheel;
• measuring a toe angle and position of the left and right rear vehicle wheels with respect to the reference on the respective left and right front vehicle wheels;
• calculating a center of thrust-line reference of the rear vehicle wheels from the toe angle and position of the left and right rear vehicle wheels;
• referenced to the toe angle of the respective left and right front vehicle wheels;
• subtracting algebraically the toe angle of the left and right rear vehicle wheels from the thrust-line reference to determine a toe angle of the left and right front vehicle wheels in relationship to the thrust-line reference;
• and setting the toe angle of the left and right front vehicle wheels to a desired toe angle in relationship to the thrust-line reference and maintaining the steering wheel in centered position.

A method for measuring angular relationships of the wheels of a vehicle comprising the steps of:

• providing a head unit;
• positioning the head unit in a predetermined relationship with a first vehicle wheel;
• selectively projecting beams relative to the head unit and to beam receiving means disposed relative to second and third vehicle wheels;
• positioning the beam receiving means in a pre-selected relationship with respect to said second and third vehicle wheels;
• measuring the positional orientation of the rear-most pair of vehicle wheels relative to a reference axis;
• calculating a vehicle thrust-line reference from the positional orientation of the rear-most pair of the vehicle wheels established by beams projected to beam receiving means associated with such rear-most wheel pair;
• and measuring the angular relationship between the forward-most pair of vehicle wheels and the calculated thrust-line reference.

A method for measuring angular relationships of vehicle wheels comprising the steps of:

• providing a head unit;
• positioning the head unit in a pre-determined relationship with a first vehicle wheel;
• selectively projecting a beam relative to the head unit and to beam receiving means;
• positioning the beam receiving means in pre-selected relationships with respect to other vehicle wheels;
• measuring the angular relationship between the projected beam and a reference axis on the other vehicle wheels;
• and further including the steps of positioning the head unit adjacent one of the front wheels of the vehicle, providing a second head unit, positioning the second head unit in a pre-determined relationship with another of the front wheels of the vehicle, selectively projecting a beam relative to the second head unit to a beam receiving member, and positioning the beam receiving member adjacent each of two rear vehicle wheels for receipt of the projected beam.

A method for measuring toe of wheels on a vehicle comprising the steps of:

• mounting a head unit on a front wheel;
• mounting beam receiving members on the front wheel opposite the head unit and the rear wheel axially adjacent the head unit;
• selectively projecting a first beam across the front of the vehicle to measure front wheel toe and a second beam to the axially adjacent rear wheel to determine rear wheel position and toe;
• mounting a head unit on another front wheel;
• mounting beam receiving members on the front wheel opposite such other front wheel and the rear wheel axially adjacent the other front wheel;
• selectively projecting a third beam across the front of the vehicle to measure front wheel toe and a fourth beam to the axially adjacent rear wheel to determine rear wheel position and toe;
• calculating a vehicle thrust-line reference from the toe and positions of the rear wheels;
• and measuring front wheel toe in relation to the vehicle thrust-line reference.

A system for centering the steering wheel and measuring toe of wheels on a vehicle comprising:

• means for maintaining the steering wheel in a fixed center position;
• a first head unit;
• a first wheel clamp mounting the first head unit on the left front wheel;
• a second head unit;
• a second wheel clamp mounting the second head unit on the right front wheel;
• a first turret assembly connectable to a power supply and carried by the first head unit to selectively project a first light beam across the front of a vehicle to measure left front wheel position and to selectively project a second light beam to the axially adjacent left rear wheel to determine left rear wheel toe;
• a second turret assembly connectable to a power supply and carried by the second head unit to selectively project a third light beam across the front of the vehicle to measure right front wheel position and to selectively project a fourth light beam to the axially adjacent right rear wheel to determine right rear wheel position;
• each of the first and second turret assemblies comprising a lamp, a toe condenser and lens assembly, and a tracking condenser and lens assembly which are positioned on parallel optical axes;
• each of the turret assemblies further including a turret rotatable about a shaft relative to the base of the turret assembly and a signal generator coupled to the turret assembly to produce a signal value proportional to the rotation of the turret;
• targets mounted on the head units of the left and right front wheels;
• mirrors mounted on each of the left and right rear wheels;
• means connecting the signal generators to a computation means;
• and meter means coupled to the computation means for indicating the amount of toe in the left and right front wheels in relation to a vehicle thrust-line reference calculated from the rear wheel positions on the vehicle whereby each of the first and second turrets on the first and second head units can be operated to selectively project beams directly to the targets of the head units and indirectly thereto through mirrors thereby causing signal values produced by the signal generator to be transmitted to the computation means and calculated values therefrom visually displayed on the meter means.