Fine grade indicating system

Claim 1

A high-low-on-grade level indicating system for use in conjunction with a road bed type fine grading machine adapted to operate on a grading surface, comprising: a support means rigidly mounted on said machine aft of its grading mechanism, said support means including at least one generally vertical hollow sleeve-like means; a sensor arm slideably mounted within said sleeve-like means and moveable up and down therein; ground engaging means operatively connected to said sensor arm for engaging the grading surface and moving said sensor arm vertically up or down in response to changes in grade detected by said ground engaging means as it traverses the grading surface; a plurality of switch means, including a series of individual switches, associated with said high-low-on-grade level system; switch manipulating means assigned with said sensor arm and operatively connected to said plurality of switch means for actuating respective switches of said switch means in response to the up or down movement of said sensor arm within said sleevelike means; and a plurality of grade indicator means operatively connected to said switch means for indicating the grade level detected by said ground engaging means in response to the actuation of said switch manipulating means by the up or down movement of said sensor arm within said sleeve-like means resulting from corresponding up or down movement of said ground engaging means.