The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 14, 1989
Filed:
Oct. 19, 1987
Edward G Nielsen, Grand Rapids, MI (US);
Timothy E Steenwyk, Grand Rapids, MI (US);
Laser Alignment, Inc., Grand Rapids, MI (US);
Abstract
A control for an excavator controls the position of the bucket cutting edge to a desired depth accurately by a calibrating laser receiver mounted on the excavator stick member and passed through a stationary laser plane wherever the stick is moved into or out of a trench. Linear position encoders monitor the length that the actuating cylinders are extended and lookup tables convert the encoder outputs to angle representations for determining the positions of the laser receiver and the cutting edge. Other lookup tables are utilized to avoid time-consuming iterative calculation procedures to provide real-time digital process solutions of trigonometric functions. The apparatus includes a unique laser receiver comprising a plurality of linearly aligned photo receptors with associated circuitry for producing an output representative of the receptor illuminated or, if a group of receptors are illuminated, the centermost receptor illuminated. An alternative embodiment, suitable for retrofit of existing excavators, utilizes gravity-operated pendant angle sensors on each member to provide an indication of cutting edge position.