Abstract: An air-bearing gage tip or pad for a gage head is mounted on a swivel and closely follows the surface of a non-porous material without touching the surface and accommodates undulating surfaces which approach the pad at an angle and also small errors in mounting the pad normal to the surface, and additionally accepts small imperfect, surface perturbations without loss of air. The air-bearing pad features advantages in respect of increase in bearing stiffness and increase in mechanical response of the gage head and improvement in freedom from adverse effects encountered in the prior art and tending to be caused by thermal shifts and inherent hysteresis.

Abstract: An improved trimmer type road construction apparatus, particularly useful in applications requiring a high degree of maneuverability and control flexibility, which is steeringly controlled by turning a centrally disposed front track assembly in such a manner that the main frame can be raised and lowered relative to the front drive assembly without a loss of steering control; and which has an automatic steering, grade and slope control constructed to be automatically adapted to particular job specifications and locations. The trimmer also has a reclaimer assembly for removal of the excavated earth, the reclaimer assembly being automatically positionable to deposit the excavated earth in predetermined, controlled positions about the trimmer.