Aeronautics and astronautics – Aircraft sustentation – Sustaining airfoils
Reexamination Certificate
1998-11-12
2001-05-15
Jordan, Charles T. (Department: 3644)
Aeronautics and astronautics
Aircraft sustentation
Sustaining airfoils
C244S214000, C244S075100, C244S231000, C464S032000, C403S002000
Reexamination Certificate
active
06231012
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to airplane wing high lift device such as leading edges slats/flaps and trailing edge flaps. More particularly, the invention relates to the high lift drive system gearboxes used to deploy leading edge slats/flaps and trailing edge flaps.
BACKGROUND OF THE INVENTION
The mechanical power for deploying high lift devices in many commercial airplanes today involves very high speed rotational torque. Such torque is generated by a power drive unit, or system power source, and transmitted via torque tubes forming a driveline along the wing to the most outboard rotary actuator to be powered. These rotary actuators are actually gear speed reducers that reduce the rotational speed from about 700-1000 rpm to about 1-10 rpm. This increases the available torque correspondingly so that the high lift devices may be deployed with appropriate force and speed of deployment, even under adverse conditions such as ice buildup on the wing leading edge.
In some commercial airplanes, it has been possible to place the drivelines such that they align with the rotary actuator. In other airplanes, this has not been possible, and it has been necessary to utilize an “offset” gearbox to transmit the rotary power from the centerline of the driveline, forwardly to the centerline of the rotary actuator. Hence, the term “offset gearbox” has been applied to the gearbox of this invention.
A problem in this type of offset gearbox is that, due in part to its complexity, and because aircraft safety is a concern, it can be costly and time consuming to perform inspections on and to perform required maintenance activities.
SUMMARY OF THE INVENTION
One aspect of the present invention provides for an improvement in deployment of a high lift device comprising a non-back brake system for use in controlling back driven loads.
Another aspect of the present invention relates to an improved no-back offset gearbox and an improved shearout or mechanical fuse to prevent damage to other components under excessive torque loads, said shearout comprising a dedicated dog bone shaft that will avoid the nuisance shearout failures of the prior art. Said shearout additionally having a closely toleranced shear neck designed to rupture within a 20% scatter band. The shear essentially uses a quill shaft with external splines at both ends and an hourglass-shaped neck in the middle.
Still another aspect of the present invention relates to the assembly of the first stage gear and second stage pinion in that they are in a unique nesting arrangement and interconnected with the shearout. The design allows the gears to share the same bearings but remain independent and capable of rotating with respect to one another in the event of a shearout failure.
Also, the shearout extraction components are integrated into the design of the gearbox and provide a built-in capability for removing broken shearout pieces without removing or disassembly of the gearbox.
REFERENCES:
patent: 2892329 (1959-06-01), Trigilio
patent: 3090258 (1963-05-01), Zink et al.
patent: 3185413 (1965-05-01), Walker
patent: 3321988 (1967-05-01), Peras
patent: 3667214 (1972-06-01), Addie
patent: 4411546 (1983-10-01), Fischer
patent: 4669999 (1987-06-01), Miller
patent: 4971267 (1990-11-01), Fulton et al.
patent: 5474408 (1995-12-01), Dinitz et al.
patent: 5553960 (1996-09-01), Turer et al.
Cacciola Michael J.
Gardner Mark J.
Steadman Stephen T.
Best Christian M.
Jordan Charles T.
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