Blade pitch control mechanism for helicopters
AssigneeUnited Technologies Corporation
InventorsDonald L. Ferris, Robert L. Faiz
Life of this patent
Estimating the term…
Abstract
Pitch control linkage for the upper rotor of coaxial counterrotating rotors utilizes conventional swashplate, control rod and servomotor elements for changing blade pitch but without the conventional rotating and non-rotating scissors for reacting swashplate torque. This is accomplished by the use of rotating and non-rotating walking beams and combination torque reacting control rods between the walking beams and the rotatable and non-rotatable swashplate elements. Means are also disclosed for shimming the rotatable walking beams to achieve pre-track adjustment of the pitch of individual blades.
Claims9
In a helicopter, an upstanding rotor having a drive shaft, a rotor hub mounted at the upper end of said shaft, an axial passage extended through said shaft and into said hub, a variable pitch blade rotatable by said shaft having a spindle extended into said passage, a pitch control horn mounted on the end of said spindle within said passage, and means for controlling the pitch of said blade including a swashplate having rotatable and non-rotatable elements, a member rotatable by said drive shaft adjacent the lower end of the latter, a first pitch control link having a torque transmitting bearing in said rotatable member, a second link extended through said passage connecting said first link to said blade horn, and a third link having means connecting it to said first link and to said rotatable swashplate element for transmitting the rotary movement of said first link to said rotatable element.
In a helicopter, an upstanding rotor having a drive shaft, a rotor hub mounted at the upper end of said shaft, a passage extended through said shaft and into said hub, a variable pitch blade driven by said shaft having a spindle extended into said passage, a pitch control horn mounted on the end of said spindle within said passage, a swashplate having rotatable and non-rotatable elements, and blade pitch control linkage connecting said rotatable swashplate element with said blade horn comprising a transverse walking beam journaled in structure rotatable with said shaft, a first control link extended through said passage connecting said walking beam to said blade horn, a second control link having a connection at one of its ends to said walking beam and a connection at its other end to said rotatable swashplate element, said connection to said walking beam comprising a torque transmitting journal bearing so oriented as to transmit torque from said rotating walking beam to said second link, and said connection to said rotatable swashplate element comprising a self-aligning ball type joint.
In a helicopter, an upstanding rotor having a drive shaft, a rotor hub mounted at the upper end of said shaft, a passage extending through said shaft and into said hub, a plurality of variable pitch blades rotatable by said shaft having spindles extended into said passage, pitch control horns fixed to said spindles within said passage, and means for controlling the pitch of said blades including a conical member fixed to said shaft at its upper and smaller end having a plurality of spaced peripheral lands at its lower end, a plurality of mounting blocks secured to said lands, a swashplate having rotatable and non-rotatable elements, said rotatable element having a hub on which said swashplate is universally mounted, said hub having arms secured to said blocks, a transverse walking beam on each of said blocks, a blade pitch control rod extended through said passage connecting each walking beam to a different blade horn, blade pitch control links connected at one of their ends to said beams and at their other ends to said rotatable swashplate element, all of said links save one having self-aligning ball type joints forming said connections at both ends, the odd link having a self-aligning ball type joint connecting it to said rotatable swashplate element and a second journal bearing connecting it to said walking beam, said second journal bearing being so oriented as to transmit torque from said rotating walking beam to said rotatable swashplate element.
Dependencies are inferred from the claim text.