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:
Oct. 16, 1979
Filed:
Mar. 20, 1978
Gregory J Korkosz, Malibu, CA (US);
Summa Corporation, Las Vegas, NV (US);
Abstract
In some helicopters power is transmitted from a gearbox adjacent the engine to the tail rotor by a long shaft. To minimize weight, a tubular shaft is used, which rotates at supercritical speeds. Vibrations resulting from shaft unbalance are magnified by resonance as the shaft passes through its critical speeds making it essential that the shaft be finely balanced. This is accomplished by slowly rotating the shaft about its axis while measuring at a chosen station along its length both the wall thickness of the tubular shaft and the distance from a fixed reference plane to the outer surface of the shaft. From these data are determined the local cross sectional area and the location of the center of gravity at the chosen station. From the latter two quantities are determined both the amount of counterweight required and its required angular location around the shaft, for the chosen station. The measurements are repeated at a large number of stations along the shaft. Self-adhering aluminum tape is used as the counterweight, which is applied to the outer surface of the shaft in a continuous manner along its length. The number of layers of tape and their width determine the amount of weight applied. It is assumed that the variation in mass density of the shaft is negligible.