Bypass valve mechanism

Claim 2

In a gas turbine engine of the type having a casing structure supporting first and second independently rotatable compressor rotors arranged in serial flow relationship for pressurizing fluid in an annular passage, the improvement comprising: means for selectively bypassing a predetermined and variable portion of the fluid pressurized by said first compressor rotor, said means including a plurality of circumferentially spaced bypass passages formed through said casing structure and communicating with said annular passage, a valve member for each said bypass passage, each said valve member hingeably connected to said casing structure for rotation to and from a position closing its respective bypass passage, and means for rotating said valve members in unison about their hinge connections to close or variably open communication between said annular passage and said bypass passages, said valve member rotating means comprising a unison ring disposed within said casing structure and extending generally coaxially around said annular passage, a bellcrank for each said valve member, each said bellcrank secured to said casing structure for rotation about an axis generally radial of said annular passage and having a first arm pivotally connected to said unison ring and a second arm pivotally and linkably connected to said valve member, and means for rotating said unison ring.

Claim 3

The improved gas turbine engine of claim 1 furthEr characterized in that said unison ring rotating means comprise at least one drive bellcrank secured to said casing structure for rotation about an axis generally radial of said annular passage, said drive crank having a first and second arm projecting from its rotational axis, said first arm pivotally connected to said unison ring, and actuator means connected to said second arm of said drive crank.

Claim 4

The improved gas turbine engine of claim 1 further characterized in that said casing structure, in part, defines a streamline outer boundary for said annular passage, with said valve member adapted to define a generally streamline continuation of said outer boundary when disposed in said closing position.

Claim 5

The improved gas turbine engine of claim 1 further characterized by and including track means carried by said casing structure for supporting said unison ring, said unison ring formed with a cylindrical inner surface for slidingly and telescopingly engaging said track means.

Claim 6

A turbofan engine having a core engine casing projecting into an annular fan duct and defining an annular fan duct passage therebetween having an exhaust nozzle at its downstream end, said core engine casing defining, in part, an annular core engine flow passage having an inlet opening to said fan duct passage, first and second axial flow compressor means arranged in serial flow relationship along said core engine flow passage for pressurizing fluid flow therethrough, said core engine casing defining a generally streamline outer boundary for said core engine flow passage intermediate said first and second compressor means, a plurality of circumferentially spaced bypass passages formed through said core engine casing, each said bypass passage formed with an inlet opening to said core engine flow passage, intermediate said first and second compressor means, and an outlet opening to said fan duct passage, a valve member for each said bypass passage, each said valve member hingeably connected to said core engine casing structure for rotation between a position closing communication between its respective bypass passage and said core engine flow passage and a position variably opening said communication, said valve members adapted to form a generally streamline continuation of said core engine flow passage streamline outer boundary when in said closing position, and means for rotating said valve members in unison between said closing and variably open positions.

Claim 7

A turbofan engine having a core engine casing projecting into an annular fan duct and defining an annular fan duct passage therebetween having an exhaust nozzle at its downstream end, said core engine casing defining, in part, an annular core engine flow passage having an inlet opening to said fan duct passage, first and second axial flow compressor means arranged in serial flow relationship along said core engine flow passage for pressurizing fluid flow therethrough, said core engine casing defining a generally streamline outer boundary for said core engine flow passage intermediate said first and second compressor means, a plurality of circumferentially spaced bypass passages formed through said core engine casing, each said bypass passage formed with an inlet opening to said core engine flow passage, intermediate said first and second compressor means, and an outlet opening to said fan duct passage, a valve member for each said bypass passage, each said valve member hingeably connected to said core engine casing structure for rotation between a position closing communication between its respective bypass passage and said core engine flow passage and a position variably opening said communication, said valve members adapted to form a generally streamline continuation of said core engine flow passage streamline outer boundary when in said closing position, and means for rotating said valve members in unison between said closing and variably open positions.

Claim 8

The turbofan engine of claim 6 further characterized in that each said valve member includes a generally rectangular valve plate, and a lug joining and projecting radially outwardly from each said valve plate, with said hinge connections disposed along the upstream edges of their respective valve plates and adjacent their respective bypass passage inlets, said valve member rotating means including a unison ring disposed within said casing upstream of said bypass passages, a bellcrank assembly for each said valve member journaled to said casing, intermediate said unison ring and said bypass passages, for rotation about an axis generally radial of the longitudinal axis of said core engine flow passage, each said bellcrank including a first arm extending from the bellcrank rotational axis and pivotally connected adjacent its distal end to said unison ring, and a second arm extending from the bellcrank rotational axis and pivotally and linkably connected adjacent its distal end to its respective valve member lug, whereby rotation of said unison ring about the longitudinal axis of said core engine flow path effects unison rotation of each said valve member about its hinge connection, and means for rotatably driving said unison ring about said core engine flow path longitudinal axis.

Claim 9

The turbofan engine of claim 6 further characterized in that said means for rotatably driving said unison ring includes at least one drive bellcrank journaled for rotation to said core engine casing about an axis generally radial of said core engine flow pAssage, said drive bellcrank including a first and a second arm projecting from said bellcrank rotational axis, said first drive crank arm pivotally connected adjacent its distal end to said unison ring, and actuator means, including a piston rod pivotally connected to said second drive crank arm adjacent its distal end.

Claim 10

The turbofan engine of claim 7 further characterized in that said unison ring is generally C-shaped in cross section and defines an axially downstream opening circumferential groove sized to receive the distal ends of said bellcrank first arms with sufficient clearance to permit relative radial movement therebetween each said first arm pivotal connection comprising ball joint means carried by said first arm and slidingly secured to said unison ring along an axis radial of said core engine flow passage.