Flat Key Groove Profiling via Variable Milling Depth
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Solution Overview
Problem
Existing methods for producing flat keys with detectable height structures are not effective in preventing key duplication, as they rely on insert elements or uniform groove depths, making it easy to replicate the keys.
Innovation Solution
A method involving a milling tool with varying penetration depth to create grooves with undercut walls and varying depths, forming a continuous height structure that is difficult to replicate, and a flat key design with bonded height structures across the groove width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If insert elements or uniform groove depths are used in flat key design, then key manufacturing is simplified, but key security against duplication is reduced
Solution Approach 1:
The patent applies local quality by creating zones with different groove depths along the key shaft. The milling cutter is displaced in the transverse direction during milling, resulting in some sections having greater groove depth than others. This non-uniform groove depth distribution makes key duplication more difficult while maintaining a relatively simple manufacturing process using conventional milling equipment.
2Device complexity
If conventional milling methods with constant penetration depth are used, then manufacturing process is simple, but groove patterns are uniform and easy to replicate
Solution Approach 1:
The patent applies dynamics by varying the penetration depth of the milling cutter during the milling process. Instead of maintaining a constant penetration depth, the cutter's depth is dynamically adjusted by displacing it in the transverse direction during milling. This creates non-uniform groove depths that are difficult to replicate, while the overall milling process remains relatively simple and uses conventional equipment.
3Manufacturing precision
If the milling cutter is displaced transversely during milling, then groove depth variation is achieved, but manufacturing precision control becomes more complex
Solution Approach 1:
The patent applies parameter changes by modifying the penetration depth parameter of the milling cutter during the milling process. The cutter is displaced in the transverse direction, which changes the effective penetration depth at different sections of the key shaft. This parameter variation creates the desired non-uniform groove depth pattern while using a relatively simple displacement mechanism that does not require complex control systems.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a method for producing a profile groove in a flat key. A milling tool (11) is used to cut a groove (2) into a blank (1). To create a height structure (6), the cutting depth of the milling tool (11) is varied while cutting the groove (2). This results in a structure that can be detected by a locking pin and is materially bonded to the blank (1).