Tolerance Compensating Circuit Board Lever Mechanism
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Solution Overview
Problem
Existing systems for mounting circuit boards into motherboards in complex aerospace systems face reliability issues due to manufacturing tolerances, which can lead to incomplete electrical connections, and previous solutions, such as levers and biasing arrangements, are often complex and insufficient.
Innovation Solution
A control module design that uses levers with pivotally mounted brackets and Belleville washers to ensure a secure connection by compensating for tolerance build-up through a mechanism where the levers pivot to engage Belleville washers, pulling the circuit boards into place, and a locking pawl to maintain the connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional levers are used to lock LRMs into the chassis, then the LRM can be secured in place, but the manufacturing tolerances cause insufficient LRM travel to ensure reliable electrical connection
Solution Approach 1:
The lever is designed to pivot dynamically during the insertion process, allowing it to accommodate tolerance variations. The pivot mechanism enables the lever to move between positions, providing adaptive travel that compensates for manufacturing tolerances and ensures reliable electrical connection despite variability in assembly dimensions.
Solution Approach 2:
The invention changes the geometric parameters of the lever and bracket assembly to create a pivot mechanism that increases the effective travel distance. By adjusting the pivot point location and bracket dimensions, the system achieves greater LRM travel capability within the same manufacturing tolerance ranges, improving connection reliability without requiring tighter manufacturing precision.
2Reliability
If various biasing arrangements are proposed to compensate for tolerances, then LRM travel can be improved, but the device complexity increases
Solution Approach 1:
The biasing function is merged into the lever and bracket assembly itself rather than being a separate mechanism. The pivot mechanism inherently provides the biasing action needed to push the LRM against the motherboard, eliminating the need for additional springs or actuators. This integration maintains simplicity while achieving reliable electrical connections through the geometric design of the pivot system.
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
Ensures a reliable and secure electrical interface by providing adequate LRM travel to account for tolerance stack-up, ensuring consistent connections and easy removal of circuit boards.
Implementation Method 1
Belleville washers to ensure a secure connection by compensating for tolerance build-up through a mechanism where the levers pivot to engage Belleville washers, pulling the circuit boards into place
Data Source
Figure 1A~1B
Figure 2
Figure 3A~4
AI summary
A control module (20) comprises a motherboard (24) and at least one circuit board (26) removably connected to the motherboard (24). There is at least one lever (28) connected to the removable circuit board (26). The lever (28) is moveable between a release and locked position. The lever (28) contacts a lock bracket (38) in the locked position to move the bracket against a spring force, such that a bias force maintains the at least one circuit board (26) in contact with the motherboard (24).