Reversible Thin Key With Dual-Sided Serrations
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Solution Overview
Problem
Existing keys for cylinder locks either lack reversibility due to asymmetrical designs or are difficult to duplicate due to symmetrical serrations, and they often compromise on thickness and strength due to additional features like grooves or walls.
Innovation Solution
A key design featuring a blade with serrations on both sides, where notches on one side are symmetrically positioned and sized to match the thickness, allowing for reversible insertion and enhanced security by preventing easy duplication, while maintaining a thin and strong structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If serrations are formed on both sides of the blade to prevent easy duplication, then security is improved, but the blade thickness increases
Solution Approach 1:
The patent positions notches on opposite sides of the blade such that their depths sum to the blade thickness, utilizing the thickness dimension efficiently. This allows serrations on both sides without increasing overall blade thickness, resolving the contradiction between security (serrations on both sides) and blade thickness.
Solution Approach 2:
The blade is segmented into multiple notches (first and second notches) positioned at different locations. Each notch contains serrations that engage with corresponding tumblers, distributing the security function across multiple segments rather than requiring a single thick section.
2Reliability
If a wall is added to prevent duplication, then security is improved, but the blade becomes thicker
Solution Approach 1:
Instead of adding a wall that increases thickness, the patent uses notches cut into the blade faces. The notches have depths that sum to the blade thickness, utilizing the existing thickness dimension to create duplication-resistant features without adding to the overall blade thickness.
3Reliability
If an asymmetrical design is used, then duplication difficulty is improved, but reversibility is lost
Solution Approach 1:
The patent employs asymmetrical notch positioning and serration patterns on opposite sides of the blade. The first notch and its serrations differ from the second notch and serrations, creating difficulty for duplication while maintaining reversibility through careful symmetrical placement relative to the blade center.
Solution Approach 2:
The patent creates reversibility by positioning notches and serrations such that the blade can be inserted with either side facing forward. The asymmetrical features are arranged to engage tumblers correctly regardless of which side of the blade is inserted first, allowing the key to function in reversed orientation.
Data Source
AI summary
A thin key that is thin but includes serrations on each of two opposite sides of a blade (42, 72). The key is associated with a cylinder lock including a rotor (13) with tumblers (21-28) retained in the rotor. The blade, which is for insertion into the rotor of the cylinder lock, includes opposite first and second wide sides (F1, F3; F2, F4) and opposite first and second narrow sides (51, 74; 52, 75). A first notch (54, 76) is formed in the first wide side and a second notch (64, 86) is formed in the second wide side. The first and second notches each have a serrated wall (54a, 76a; 64a, 86a) engageable with the tumblers. The first notch and the second notch are spaced apart so that they do not overlap each other. The sum of the depths of the first and second notches (L1, D1; L2, D2) is greater than or equal to the thickness of the blade (L3, D3).