Combination Lock Disc Securing Mechanism Prevents Axial Disengagement
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Solution Overview
Problem
Conventional combination locks face issues with unintentional code changes due to axial separation of the clutch plate from the first tumbler disc during forced movement, leading to unknown new combination codes.
Innovation Solution
A combination lock design that includes a locking lever with a disc securing portion to prevent axial disengagement of the tumbler discs from the drive portion, ensuring the clutch plate and innermost tumbler disc remain axially fixed or captured when the locking bolt is retracted, thereby preventing unintended code changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the locking lever is permitted to move freely to engage with aligned notches during dial rotation, then the locking member can be actuated to release the lock, but the tumbler discs may axially disengage from the drive plate causing unintended code changes
Solution Approach 1:
A disc securing portion is introduced as an intermediary component between the locking lever and the tumbler discs. This securing portion engages with the drive plate to prevent axial disengagement of the tumbler discs during lever movement, thereby mediating between the need for lever freedom of movement and the need to maintain disc positioning integrity
Solution Approach 2:
The solution addresses the problem by adding a dimensional constraint in the axial direction. The disc securing portion provides axial positioning that prevents separation along the axis while allowing the locking lever to move freely in its operational direction, thus solving the contradiction by constraining motion in one dimension without affecting operation in another
2Adaptability or versatility
If the dial is rotated to successive positions to align notches in tumbler discs, then the combination can be changed by separating the drive plate from the first tumbler disc, but forced movement may cause unintentional code changes
Solution Approach 1:
The disc securing portion acts as a mediator that distinguishes between authorized code changes (performed with the lock in a specific state) and unauthorized forced changes. It allows legitimate combination changes while preventing unintended changes during forced movement or operation
Solution Approach 2:
The disc securing portion provides preliminary protection against axial disengagement before any forced movement occurs. By pre-establishing the axial constraint, it prevents the harmful effect of unintended code changes before they can happen during dial rotation or forced movement
Data Source
AI summary
A combination locking arrangement includes a locking member, a locking lever connected to the locking member; and at least first and second tumbler discs rotatable about a tumbler disc axis. When each of the tumbler discs is rotated to an unlocking orientation, the locking lever engages aligned recesses in the tumbler discs, such that further rotation of the tumbler discs moves the locking member from the locking position to the releasing position. A dial is rotatable about the tumbler disc axis for selective rotation of the tumbler discs, and includes a drive portion rotationally secured in interlocking engagement with the first tumbler disc in one of a plurality of code selecting orientations. The locking lever includes a disc securing portion positioned to prevent axial disengagement of the first tumbler disc from the dial drive portion when the locking lever is engaged with the aligned recesses in the tumbler discs.