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:
Aug. 09, 2005
Filed:
Jul. 01, 2002
David Ferullo, Saint Mitre les Remparts, FR;
David Ferullo, Saint Mitre les Remparts, FR;
Eurocopter, Cedex, FR;
Abstract
A drag damper for use on a rotary-wing aircraft rotor comprises a body defining two variable volume chambers linked by a piston. The chambers filled with fluid in the damper are connected by a restrictor port in the piston or between the latter and the body, and via a channel of great length and small cross-section compared with the cross-section of the body, in which elastic means bear against and load the piston-rod assembly towards a neutral position, the anti-resonance frequency of the damper being matched substantially to the nominal rotation frequency of the rotor, and the restrictor port providing effective damping at the natural frequency (ωδ) of the blades in drag, differing by construction from the rotor frequency (Ω).