Fusible Nut Assembly Wedge Positioning
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Solution Overview
Problem
The existing mechanical connection between primary and secondary nuts in aircraft THSA actuators requires complex and costly instrumentation for precise assembly, making the process time-consuming and inefficient.
Innovation Solution
An assembly featuring adjustable spacing means forming a wedge between the primary and secondary nuts, along with a fusible driving mechanism, allows for quick and secure positioning without the need for expensive or time-consuming equipment, utilizing a link that breaks under a predetermined load to facilitate force transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If complex instrumentation is used to hold the two nuts in precise relative position during assembly, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The wedge is pre-adjusted to the correct thickness to establish the precise play between the secondary nut and screw threading before assembly. This preliminary adjustment eliminates the need for complex instrumentation during the actual assembly process, as the correct positioning is already built into the wedge structure.
Solution Approach 2:
The wedge acts as an intermediary element between the primary and secondary nuts, providing the necessary spacing to achieve precise play. By introducing this intermediate component with predetermined thickness, the complex direct positioning of two nuts is simplified into a single-component solution.
2Manufacturing precision
If complex instrumentation is used for precise assembly positioning, then manufacturing precision is improved, but assembly time increases
Solution Approach 1:
The wedge is pre-adjusted to the correct thickness to establish the precise play between the secondary nut and screw threading before assembly. This preliminary adjustment eliminates the need for complex instrumentation during the actual assembly process, as the correct positioning is already built into the wedge structure.
3Reliability
If the pin acts as a fuse to break under predetermined load, then reliability is improved, but the pin structure becomes more complex
Solution Approach 1:
The pin's cross-sectional dimensions are specifically designed to fail at a predetermined load level. By controlling the geometric parameters of the pin (its cross-section size), the failsafe function is achieved through simple dimensional design rather than complex structural mechanisms.
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
This solution enables a simplified and faster assembly process while maintaining optimal reliability during primary nut failure, ensuring precise play and efficient force transmission without heavy or costly equipment.
Implementation Method 1
adjustable spacing means forming a wedge between the first and second nuts
Implementation Method 2
the link comprises a portion with cross-section sized so as to break under a predetermined load
Data Source
AI summary
The assembly comprises a first and a second nut intended to cooperate with a screw in particular provided in an adjustable tailplane actuator for an aircraft, and a mechanical connection between the first and the second nut comprising means for fusible driving of the second nut by the first nut, in which the mechanical connection also comprises adjustable spacing means forming a wedge between the first and second nuts.