Actuator mechanism for variable angle vane arrays
First Claim
1. An actuator mechanism for a variable angle vane array for use in a fluid flow machine of the type having an axis and a casing,the variable angle vane array comprising a plurality of vanes, the vanes are pivotably mounted in the casing about radial axes, the vanes are pivotable between a first position giving maximum fluid flow delivery, and a second position giving minimum fluid flow delivery, each vane having a radially outer end,the mechanism comprising a lever arm in the form of a gear segment secured to the radially outer end of each vane for effecting pivoting movement thereof, anda toothed unison ring meshing with the gear segments for simultaneous transmission of pivoting movement to each vane through their respective gear segments,wherein, the gear segments and the unison ring are provided with emergency drive means which engage to cause the gear segments to turn beyond toothed engagement with the unison ring so as to pivot their respective vanes to an effective zero fluid delivery position.
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Accused Products
Abstract
A power turbine includes a stage of pivotable nozzle vanes. The individual vanes are pivoted by connecting them to a toothed unison ring via actuating levers in the form of gear segments. The gear segments only have sufficient teeth to enable pivoting of the vanes between normal maximum and minimum operating angles. If an emergency closure of the nozzle is required, the unison ring pivots the gear therewith, whereupon pins on the unison ring engage projections on each segment, thus causing the segments to continue pivoting the vanes to a closed position.
47 Citations
11 Claims
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1. An actuator mechanism for a variable angle vane array for use in a fluid flow machine of the type having an axis and a casing,
the variable angle vane array comprising a plurality of vanes, the vanes are pivotably mounted in the casing about radial axes, the vanes are pivotable between a first position giving maximum fluid flow delivery, and a second position giving minimum fluid flow delivery, each vane having a radially outer end, the mechanism comprising a lever arm in the form of a gear segment secured to the radially outer end of each vane for effecting pivoting movement thereof, and a toothed unison ring meshing with the gear segments for simultaneous transmission of pivoting movement to each vane through their respective gear segments, wherein, the gear segments and the unison ring are provided with emergency drive means which engage to cause the gear segments to turn beyond toothed engagement with the unison ring so as to pivot their respective vanes to an effective zero fluid delivery position.
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10. A variable angle vane having first and second ends and an axis of rotation extending longitudinally of the vane,
the vane having a lever arm in the form of a gear segment secured to, and extending substantially perpendicular from the first end of the vane, the gear segment having first and second extremities, the lever arm having a projection extending substantially longitudinally, relative to the vane, from the lever arm, the projection being located at the first extremity of the gear segment.
Specification