Grade checker

Details Grade checker Grade checker

1978-10-02

1980-07-29

Stephan, Steven L.

Geometrical instruments

Straight-line light ray type

Multisight line

33282, 33286, G01C 900, G01C 500, G01C 1500

Patent

active

042143730

ABSTRACT:
A grade checker for determining the elevation of a grade relative to a pair of reference points spaced apart on opposite sides of the grade. The checker comprises an elongated sighting tube vertically orientable between the reference points and including a pair of inclined, oppositely facing reflecting surfaces at its lower extremity. The sighting tube can be raised to horizontally align the reflecting surfaces with the reference points, as determined by viewing through a window at the upper extremity of the sighting tube. The amount by which the sighting tube must be raised to effect such alignment is indicated, thereby indicating the elevation of the grade relative to the reference points.

REFERENCES:
patent: 688826 (1901-12-01), Clark
patent: 3300861 (1967-01-01), Lilly

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