Apparatus for measuring wheel alignment of motor vehicles

摘要

The system of the present invention provides means for quick and accurate measurement of various wheel alignment parameters of motor vehicles by the use of reflected light beams. A laser source mounted near the front end of the vehicle provides a pair of light beams directed 180 degrees apart across the front end of the vehicle. Each of the beams is reflected along the side of the vehicle by a roof mirror set mounted near each front corner of the vehicle. The mirror sets each deflect a beam through a constant net angle of 90 degrees for a wide range of angles of incident light so that the laser source can be rotated to quickly provide parallel beams which are aligned substantially parallel to the sides of the vehicle. These mirror sets also provide stable beams and present small movements thereof from affecting the accuracy of the measurements being made. A pair of relay roof mirror sets, positioned adjacent the wheels whose alignment parameters are being measured, each reflects the beams onto flat mirrors pendulously mounted on the wheels. Each flat mirror returns the beam to the associated relay roof mirror set which, in turn, reflects the beam back to a grid-like light responsive target. The position of the return beam on the target causes the target to provide electronic output signals to logic circuitry which calculates the camber, caster and toe angle of the associated vehicle wheel.