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:
Mar. 07, 1989
Filed:
Nov. 12, 1987
William B Wright, Derby, GB;
Rolls-Royce plc, Longdon, GB;
Abstract
A pitch arrangement for a variable pitch fan assembly of a turbofan gas turbine engine comprises a plurality of fan blades, each of which has a root portion rotatably mounted, in a thrust bearing on a fan rotor. A control ring is arranged coaxially with and is rotatably mounted on the fan rotor, and each of the fan blades is connected to the control ring by a lever arm. The pitch of the fan blades is varied by rotation of the control ring in either direction. A plurality of hydraulic rams are arranged to drive the control ring through a plurality of bell cranks. The hydraulic rams are mounted on the fan rotor so that the pistons and shafts move in a radial direction such that the centrifugal force of the pistons and shafts is applied to the bell cranks so that a counter turning movement is applied to the control ring to oppose the centrifugal turning moment of the fan blades.