Abstract: A wheel alignment measuring system for measuring front wheel toe including a laser beam light projector mounted on a front wheel of a motor vehicle which projects a beam of light onto a pivotally mounted front mirror on the projector which oscillates back and forth through a ten degree angle about a reference line The beam of light reflected from the oscillating mirror swings ten degrees on either side of a central reference beam line, and during its swing the beam strikes a fixed roof mirror mounted on the opposite front wheel of the vehicle The thus reflected beam sweeps back and forth across the light projector and is successively intercepted by each of a pair of closely spaced photocells on the light projector, the cells being equally spaced on opposite sides of the reference beam line The cells develop signals when they intercept the light beam which signals control and up/down counter through a flip-flop The time interval required for the moving light beam to fall on a first cell, sweep in one outward direction and return in the opposite direction to the second cell is compared with the time interval required for the beam to continue its sweep from the second cell in said opposite direction and return in said one outward direction to the first cell Such comparison is stored by the counter as a binary difference signal A digital/analog converter converts the binary difference between these time intervals into a voltage which represents the total toe angle between the front wheels The toe angle of the projector-mounting front wheel is obtained in a similar manner by sweeping a rearwardly directed light beam across a fixed roof mirror on the rear wheel that is directly behind said front wheel In the preferred embodiment, the direction or "sense" of the oscillating light beam is obtained by employing two photocells on opposite sides of a reference line so that the paired cells intercept the beam in one order on an outward sweep and in the opposite order on a return sweep In a modified embodiment, a single cell replaces the paired cells, and a switch, which is operated by a cam on the motor shaft that swings the mirror, provides signals to a circuit which determines the direction of beam swing

Abstract: 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.

Abstract: In a system for aligning a wheel employing means for generating electrical signals indicative of camber, toe and the rotational position of the wheel when the camber and toe readings are sensed employs an improved sensor assembly for generating the toe readings. The same sensor assembly can also be used with respect to providing a reference with respect to certain rear wheel relationships.

Abstract: A master slave steering system is provided for earth construction machinery having front and rear steerable wheels or tracks. A front steering sensor is connected to control the front wheel or track, and the rear wheel or track is controlled either from a rear steering sensor in an automatic mode or in response to the steering of the front wheel or track in a slave mode to insure that, in the automatic mode, the front and rear wheels or tracks are rotated independently as dictated by their respective sensors and, in the slave mode, the front and rear wheels or tracks are rotated in an opposite direction with respect to one another.

Abstract: An agricultural tractor with over-size front tires for use with a mechanical front wheel drive is provided with large caster angle front wheels to allow a front wheel to tuck under the tractor to achieve small radius turns.

Abstract: A vehicle wheel alignment device for determining or checking the toe of the steerable wheels of a vehicle, and in which device the wheel toe measurements are displayed at the rear and front of the wheels to visually show the toe alignment, as well as being displayed, if desired, at a location beneath the vehicle adjacent the tie rod ends where wheel toe is normally adjusted.