Variable pitch arrangement for a gas turbine engine
First Claim
1. A variable pitch arrangement for a gas turbine engine comprising:
- a rotor having an axis of rotation;
a plurality of first blades being arranged circumferentially on and extending radially from the rotor, the plurality of first blades being rotatably mounted on the rotor to allow the pitch of the first blades to be varied, wherein each first blade has a circular root portion having gear teeth on at least a portion of its circumference, a leading edge and a trailing edge;
a plurality of second blades being arranged circumferentially on and extending radially from the rotor, the plurality of second blades being rotatably mounted on the rotor to allow the pitch of the second blade'"'"'s to be varied, wherein each second blade has a circular root portion having gear teeth on at least a portion of its circumference, a leading edge and a trailing edge;
wherein the plurality of first blades and the plurality of second blades are arranged to e rotatably mounted in a plane substantially perpendicular to ht axis of rotation of the rotor, and arranged alternately circumferentially, the number of second blades being equal to the number of first bladesfirst actuator means being arranged to vary the pitch of the plurality of first blades only, the first actuator comprising a first annular member having gear teeth on its circumference which mesh only with the gear teeth on the root portions of the first blades;
second actuator means being arranged to vary the pitch of the plurality of second blades only, the second actuator comprising a second annular member having gear teeth on its circumference which mesh only with the gear teeth on the root portions of the second blades;
wherein the first actuator means and the second actuator means vary the pitch of the first blades and the second blades independently of each other so that ht leading edges of the first blades are prevented from contacting the trailing edges of the second blades.
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Accused Products
Abstract
A variable pitch arrangement to enable reverse pitch settings of fan blades to be achieved without the leading and trailing edges of adjacent fan blades abutting each other comprises two sets of fan blades and two sets of actuators. The two sets of fan blades are rotatably mounted on the fan rotor, and arranged circumferentially on the fan rotor. The blades in the first set of fan blades are arranged alternately circumferentially with the blades in the second set of fan blades. There are equal numbers of blades in each set of fan blades. The two sets of actuators act independently of each other on the two sets of fan blades such that the pitch of the blades in the first set and the pitch of the blades in the second set are varied in a phased relation to prevent fouling of the blades. Initially one set of blades varies pitch quickly while the other set of blades varies pitch slowly, and then the first set of blades varies pitch slowly while the other set of blades varies pitch quickly.
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Citations
12 Claims
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1. A variable pitch arrangement for a gas turbine engine comprising:
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a rotor having an axis of rotation; a plurality of first blades being arranged circumferentially on and extending radially from the rotor, the plurality of first blades being rotatably mounted on the rotor to allow the pitch of the first blades to be varied, wherein each first blade has a circular root portion having gear teeth on at least a portion of its circumference, a leading edge and a trailing edge; a plurality of second blades being arranged circumferentially on and extending radially from the rotor, the plurality of second blades being rotatably mounted on the rotor to allow the pitch of the second blade'"'"'s to be varied, wherein each second blade has a circular root portion having gear teeth on at least a portion of its circumference, a leading edge and a trailing edge; wherein the plurality of first blades and the plurality of second blades are arranged to e rotatably mounted in a plane substantially perpendicular to ht axis of rotation of the rotor, and arranged alternately circumferentially, the number of second blades being equal to the number of first blades first actuator means being arranged to vary the pitch of the plurality of first blades only, the first actuator comprising a first annular member having gear teeth on its circumference which mesh only with the gear teeth on the root portions of the first blades; second actuator means being arranged to vary the pitch of the plurality of second blades only, the second actuator comprising a second annular member having gear teeth on its circumference which mesh only with the gear teeth on the root portions of the second blades; wherein the first actuator means and the second actuator means vary the pitch of the first blades and the second blades independently of each other so that ht leading edges of the first blades are prevented from contacting the trailing edges of the second blades. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification