Flat-bladed Key with Segmented Skew Cut Bitting for Torque Strength
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Solution Overview
Problem
Existing horizontal cam locks with reversible keys face challenges in maintaining key blade strength due to extensive bitting on both sides, which compromises the key's ability to withstand torque without breaking, and lack warding features in the keyway, making them vulnerable to lock-picking.
Innovation Solution
The design incorporates skew cut bittings that extend to the edge of the key blade, allowing larger diameter rotating tumbler pins to seat correctly, with bittings divided to occupy only half the width of each side, and includes warding features on both bitted and non-bitted sections to enhance strength and security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bittings extend across almost the full width of the key blade to operate locks, then the key can operate the lock, but the key blade becomes too weak to withstand torque
Solution Approach 1:
The bitting is segmented to occupy only a portion of the key blade width rather than extending across the full width. This segmentation allows the key to engage the tumbler pins while leaving sufficient material in the center of the blade to maintain structural strength and withstand torque during operation.
2Adaptability or versatility
If both sides of the key blade are bitted to operate different locks, then the key becomes reversible and can operate multiple locks, but significant material is removed making the blade weak
Solution Approach 1:
The bitting on each side of the key blade is segmented to occupy only a portion of the width, allowing both sides to be bitted for reversibility while maintaining sufficient material for strength.
Solution Approach 2:
Different regions of the key blade have different properties: the edge regions contain bitting for lock engagement while the center region maintains full material thickness for structural strength. This local differentiation allows the key to be bitted on both sides while remaining strong enough to withstand torque.
3Ease of operation
If the keyway has no warding features, then the key can be inserted easily, but the lock is vulnerable to lock-picking
Solution Approach 1:
Warding features are added to specific locations within the keyway at strategic positions that do not interfere with the bitting engagement. These localized warding features increase security against lock-picking while maintaining ease of key insertion and operation.
Data Source
AI summary
A cylinder lock with a rotating tumbler pin, a sidebar, and a slider has a keyway with a ward projection into the center of the bitting area of a key blade received by the keyway. The tip of each rotating tumbler pin seats on the bitting surfaces remaining to the sides of this center ward of the key, and the tumbler pins that are engaged by the bitting on the side of the key blade do not seat on more than half of the width of the blade. Half the pin width is removed from each tumbler pin near the tip thereof. The key has a bitted section at which one or more bittings are formed and a non-bitted section bitting that is devoid of bitting. The bittings extend at a constant depth to an edge of the key blade.