Rotor blade pitch control by mechanical hydraulic system sensing blade deflection

Claim 3

The combination of claim 1 including means for disabling a helicopter primary blade pitch control mechanism upon operation of said device.

Claim 4

The combination of claim 2 wherein said primary control mechanism comprises gyroscopic means and a blade actuation arm connected thereto, and said applying means includes an enabling arm positioned by said device for disabling the operative connection between said gyroscopic means and blade actuation arm.

Claim 5

The device of claim 1 in which said converting means comprises, a piston means operatively connected to said sensor and amplifying means, nozzle means operatively connected to said piston means, and at least two receiving ports in the root portion of the blade, said nozzle means being directed toward said receiving ports to produce such modulated pressures for said servo power actuator means.

Claim 6

The device of claim 4 in which said piston means constitutes a dashpot cylinder means providing for faster response to any of various loads imposed upon the rotor blade.

Claim 7

The device of claim 5 in which said dashpot cylinder means comprises, a cup operatively connected to said sensor and amplifying means, a piston having a head, an orifice in said head, a pair of springs one of which is seated in said cup and against said head, the other seated in said cavity, said springs positioning said piston.

Claim 8

The combination in accordance with claim 1 wheRein, said sensor means comprises a drum secured to the rotor blade in its root region, a pulley mounted for rotation about a point at said extended portion outboard from said drum, said pulley being of smaller diameter than the drum, inelastic band means encircling said drum and pulley combination whereby deflection of the blade produces rotational movement of said pulley, and means for coupling said pulley to said converting means.

Claim 9

The combination in accordance with claim 7 wherein said coupling means comprises, a second drum secured to said pulley, a second pulley smaller than said second drum mounted for rotation about a point between said second drum and drum, and an inelastic band encircling the second drum and second pulley combination, said second pulley being connected to said converting means.

Claim 10

The combination in accordance with claim 1 wherein said sensor and amplifying means comprises an elongated valve body secured at one end to the root portion of the rotor blade and extending outwardly therefrom, said body including an internal cavity, a rigid arm in said cavity and including a shorter extension extending out of the outer end of said body, said arm and extension being fulcrumed at the outer end of said body, a member secured to the blade, said extension physically engaging said member, motion of said member with respect to the blade root being indicative of blade deflection or deformation, such motion resulting in rotation of said arm and being amplified by the ratio of the lengths of said arm and shorter extension thereof, said arm adapted to be coupled to a fluidic nozzle means in said converting means, such motion capable of selectively positioning said nozzle means with respect to either one of two receiver ports connected to said power servo actuator means depending upon the extent of blade deflection or deformation.

Claim 11

Sensor and amplifying means for sensing deflection or deformation in a single rotor blade comprising in combination, an elongated body disposed in said blade and having an internal cavity therein, an inboard end thereon adapted to be securely attached to a root portion of said blade, and an outboard end thereon towards which said internal cavity extends, an arm disposed in said internal cavity, a lobe rigidly connected to said arm and mounted substantially exteriorly of said body, said arm and lobe being pivoted at said outboard end of said body, member means adapted to be secured to said blade and disposed beyond said elongated body, said lobe physically engaging said member means for obtaining movement of said blade thereby generating a signal, whereby such movement of said member means causes movement in said arm opposite to movement of said lobe and member means, the movement of said arm providing for amplification of such signal.

Claim 12

Sensor and amplifying means for sensing deflection or deformation in a single rotor blade comprising in combination, an elongated body disposed in said blade and having an internal cavity therein, an inboard end thereon adapted to be securely attached to a root portion of said blade, and an outboard end thereon towards which said internal cavity extends, an arm disposed in said internal cavity, a lobe rigidly connected to said arm and mounted substantially exteriorly of said body, said arm and lobe being pivoted at said outboard end of said body, member means adapted to be secured to said blade and disposed beyond said elongated body, said lobe physically engaging said member means for obtaining movement of said blade thereby generating a signal, whereby such movement of said member means causes movement in said arm opposite to movement of said lobe and member means, the movement of said arm providing for amplification of such signal.

Claim 13

An antiflapping system for a rotor blade in an airborne vehicle comprising in combination, blade deflection sensor and amplifying means within a rotor blade for producing a hydraulic pressure signal responsive to a load imposed on said blade, means for sensing the pitch azimuth of the rotor blade for applying a reversed pitch signal to the rotor blade on the rearward portion of its blade rotation, means for commanding the pitch of said blade, and speed responsive means for actuating said system when the blade r.p.m. falls below a predetermined value.

Claim 14

An antiflapping system for a rotor blade in an airborne vehicle comprising in combination, blade deflection sensor and amplifying means within a rotor blade for producing a hydraulic pressure signal responsive to a load imposed on said blade, means for sensing the pitch azimuth of the rotor blade for applying a reversed pitch signal to the rotor blade on the rearward portion of its blade rotation, means for commanding the pitch of said blade, and speed responsive means for actuating said system when the blade r.p.m. falls below a predetermined value.

Claim 15

The combination of claim 11 in which said sensor and amplifying means comprises a mechanical motion means and fluidic amplifier coupled together between the root portion and an outboard portion of said blade for converting a signal imposed by a load on said blade to hydraulic pressure differentials fed to said sensing means.

Claim 16

The combination of claim 12 in which sensor and amplifying means together with said sensing means constitutes signal inputs to said commanding means controlling the pitch of said blade.

Claim 17

In combination with a vehicle including a rotor mast, hub, and blade connected to said hub, a mechanism for applying a reversed pitch signal for a single blade independently controlled of and without interaction with another blade or blades during receding movement thereof at less than or reduced below normal r.p.m. of the blade, said mechanism comprising in combination, a nonrotating cam means mechanically secured to structure of the vehicle adjacent the mast or hub on which the blade is mounted, cam follower means mounted on the blade, hub or mast adapted for cooperative engagement with said nonrotating cam means, valve means mounted on the blade, hub or mast controllable by the engagement of said cam follower means with said nonrotating cam means, said nonrotating cam means being contoured to control operation of said valve means for producing a reversed pitch signal during a preselected portion of the blade during less than or reduced below normal r.p.m. of the single blade rotation.

Claim 18

In combination with a vehicle including a rotor mast, hub, and blade connected to said hub, a mechanism for applying a reversed pitch signal for a single blade independently controlled of and without interaction with another blade or blades during receding movement thereof at less than or reduced below normal r.p.m. of the blade, said mechanism comprising in combination, a nonrotating cam means mechanically secured to structure of the vehicle adjacent the mast or hub on which the blade is mounted, cam follower means mounted on the blade, hub or mast adapted for cooperative engagement with said nonrotating cam means, valve means mounted on the blade, hub or mast controllable by the engagement of said cam follower means with said nonrotating cam means, said nonrotating cam means being contoured to control operation of said valve means for producing a reversed pitch signal during a preselected portion of the blade during less than or reduced below normal r.p.m. of the single blade rotation.

Claim 19

The mechanism of claim 14 in which said valve means includes, a valve, a first pair of conduits connected to said valve and between which pressure signals incoming to said valve are modulated, a second pair of conduits connected to said valve and between which such modulated pressure signals are transmitted from said valve, and valve spool member means displaceable by the cooperative action between said cam follower and cam whereby cross-communication between the conduits of said first and second pairs of conduits provides for reversal of transmission of such modulated pressure signals between said first and second pairs of conduits.