1
Phillip R Johnson: Laser land-surveying apparatus with digital display. Dakota Electron, Williamson Bains Moore & Hansen, June 14, 1977: US04029415 (58 worldwide citation)

A land-surveying apparatus for use with a laser beam source to obtain grade and range distances has a grade pole with a laser beam detection unit slidably mounted thereon, electrical measuring means being connected between the grade pole and the detection unit to generate an electrical grade signal ...


2
Phillip R Johnson: Tool carrying vehicle with laser control apparatus. Dakota Electron, Williamson Bains Moore & Hansen, July 31, 1979: US04162708 (55 worldwide citation)

A tool-carrying vehicle, such as a road grader, is provided with an apparatus for maintaining a predetermined distance between its blade or other tool and a laser reference plane generated by a rotating laser beam. The apparatus includes a detector housing supported on a mounting extending upwardly ...


3
Phillip R Johnson, Peter F M Prillinger, Alfred W Sieving: Control system for an integral spring-loaded parking and service brake. Caterpillar Tractor Co, Phillips Moore Weissenberger Lempio & Strabala, December 21, 1976: US03999075 (13 worldwide citation)

A control system for a spring-applied service brake which can also be used as a parking brake. Pressure from the vehicle hydraulic system is normally used to release the brakes. In the event of a loss of the primary pressure from the hydraulic system, the control system switches automatically to use ...