Grip-yoke assembly with a redundant centrifugal load support
AssigneeTextron Inc.
InventorsDavid E. Snyder, Cecil E. Covington
Life of this patent
Estimating the term…
Abstract
A grip-yoke assembly for attaching a helicopter blade to the mast of the helicopter rotor having a conventional primary coupling to carry the centrifugal loads and a redundant path operative should the primary coupling fail to insure continued operability of the blade. In one embodiment, the redundant load path has a bearing surface formed on the inboard end of the grip and a corresponding thrust bearing mounted on an inboard yoke fitting for engagement with the bearing surface upon failure of the coupling. In an alternative embodiment, a bearing surface is formed on an outboard grip fitting and a corresponding thrust bearing is supported on the yoke outboard of the grip fitting.
Claims22
A redundant coupling for attaching a helicopter rotor blade to a mast mounted yoke where a grip encompasses said yoke and is rotatably attached thereto by a primary coupling to allow blade pitch change while opposing centrifugal forces from said blade, comprising:
- a transverse member mounted on said grip;
- a restraint member on said yoke;
- and
- a thrust bearing normally free from stress supported between said restraint member and said transverse member and adapted to carry said centrifugal forces upon failure of said primary coupling to permit outward displacement of said grip to stress said thrust bearing thereby restraining said blade while maintaining pitch change capability of said blade.
In combination, means for connecting a main helicopter blade to the rotor having a yoke connected to the rotor, a grip enclosing the yoke and connected to the blade, a strap assembly connecting the grip and yoke.
- the improvement which comprises a transverse member on said grip, a portion of said yoke outboard of said transverse member normally free of centrifugal forces on said grip for contacting said transverse member and retaining said yoke in said grip upon failure of said strap.
A coupling for attaching a helicopter rotor blade to a mast comprising:
- a yoke attached to and extending from said mast;
- a grip enclosing said yoke and attached to said blade;
- bearing means interconnecting said grip and yoke to maintain relative axial alignment and permit limited radial rotation therebetween;
- a primary load supporting means connecting said yoke and grip for transferring centrifugal loads from said grip to said yoke and for allowing limited radial rotation therebetween;
- and
- redundant load supporting means on said grip and yoke normally free from said loads for transferring said loads from said grip to said yoke upon outward displacement of said grip due to failure of said primary load supporting means.
In a coupling for attaching a helicopter rotor blade to a mast comprising in combination:
- a yoke attached to and extending from said mast;
- a grip enclosing said yoke and attached to said blade;
- bearing means interconnnecting said grip and yoke to maintain relative axial alignment and permit limited radial rotation;
- a primary load supporting means connecting said yoke and grip for transferring centrifugal loads from said grip to said yoke and for allowing limited radial rotation therebetween;
- and
- the improvement which comprises a redundant load supporting means on said grip and yoke normally free of said loads and positioned to transfer centrifugal loads from said grip to said yoke upon failure of said primary load supporting means and radial displacement of said blade relative to said yoke.
Dependencies are inferred from the claim text.