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:
Apr. 19, 1988
Filed:
Dec. 09, 1986
William B Wright, Derby, GB;
Rolls-Royce plc, London, GB;
Abstract
A propeller module for an aero gas turbine engine comprising two contra-rotating propellers has a reduction gear train positioned axially between the propellers. Pitch change mechanism are provided to change the pitch of the blades of both propellers independently of the differential speed of the propellers. The pitch change mechanisms comprise two sets of hydraulic motors one set of which is mounted on a carrier member of the gear train within the planet gears, the other set is mounted on the hub of the second propeller. Pitch selector valves control the supply of hydraulic fluid to the hydraulic motors, and the pitch selector valves are operated by a pitch change power unit. The pitch selector valves are positioned coaxially of the propellers and a transfer tube extends coaxially between the pitch selector valves to transfer hydraulic fluid therebetween independently of differential speed of the propellers.