Aircraft Wiper Arm Load Adjustment With Threaded Spline Mechanism
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Solution Overview
Problem
Conventional windshield wiper systems for aircraft lack a mechanism for adjusting blade load, and those that do have such a mechanism often increase aerodynamic drag and system complexity.
Innovation Solution
A windshield wiper system with a wiper drive shaft featuring threaded and spline sections, and adjustable nuts that allow for varying blade load by axial positioning, reducing complexity and drag through a novel mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a blade load adjustment mechanism is added to the wiper system, then blade load adjustability is improved, but device complexity increases
Solution Approach 1:
The wiper arm assembly serves multiple functions: it provides structural support for the wiper blade, enables rotational movement with the drive shaft via the spline section, and allows blade load adjustment through axial positioning using the threaded sections and nuts. This multi-functionality eliminates the need for separate adjustment mechanisms, reducing overall system complexity while maintaining adjustability.
Solution Approach 2:
The adjustment mechanism is merged into the wiper arm assembly itself rather than being a separate component. The threaded sections are integrated into the drive shaft, and the nuts are attached to the wiper arm, combining the adjustment function with the existing structural elements. This merging reduces the number of discrete parts and simplifies the overall system.
2Adaptability or versatility
If a blade load adjustment mechanism is added to the wiper system, then blade load adjustability is improved, but aerodynamic drag increases
Solution Approach 1:
The adjustment mechanism is designed to be retracted or hidden within the streamlined housing of the wiper arm assembly when not in use. The threaded sections and nuts are positioned to minimize protrusion into the airflow path, extracting the adjustment functionality from the aerodynamic flow path while maintaining adjustability capability.
3Measurement precision
If threaded sections and nuts are used for adjustment, then blade load control precision is improved, but manufacturing complexity increases
Solution Approach 1:
The drive shaft is segmented into distinct functional sections: a spline section for rotational coupling and two threaded sections for adjustment. This segmentation allows each section to be manufactured and assembled independently, simplifying the manufacturing process while maintaining precision. The threaded sections can be machined or formed as separate features and then integrated into the drive shaft.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Provides adjustable blade load without increasing aerodynamic drag or system complexity, enabling precise control of wiper blade pressure on the windshield.
Implementation Method 1
The second end includes a first threaded section between the first end and the second end, a second threaded section extending axially along the wiper drive shaft between the first threaded section and the second end
Implementation Method 2
a spline section axially between the first threaded section and the second threaded section. A wiper arm assembly includes an adjustment sleeve that interlocks to the spline section
Data Source
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AI summary
A windshield wiper system for an aircraft includes a wiper drive shaft (28) with a first end and a second end opposite the first end. The second end includes a first threaded section (40) between the first end and the second end, a second threaded section (42) extending axially along the wiper drive shaft (28) between the first threaded section (40) and the second end relative to a center axis of the wiper drive shaft (28), and a spline section axially between the first threaded section (40) and the second threaded section (42). Further included is a first nut (34) to thread to the first threaded section (40), a second nut (36) to thread to the second threaded section (42), and a wiper arm assembly including an adjustment sleeve (52) configured to interlock with the spline section, a wiper arm with a first end configured to enclose the adjustment sleeve (52), and a second end of the wiper arm attached to a wiper blade.