Lock Device With Segmented Helical Keyways
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Solution Overview
Problem
Conventional lock devices require high-strength materials for the core body and face difficulties in forming recesses on the inner helical surface of helical blades, making it challenging to create effective keyways and increasing the ease of picking the lock.
Innovation Solution
The lock device incorporates a cylindrical core body with angularly spaced-apart helical keyways and tumbler units, where the tube through holes do not extend through the lock axis, allowing for increased structural strength and making it harder to form recesses on the helical blades, thus enhancing security by requiring precise geometry matching between the key and lock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the through holes extend through the central axis of the core body, then the keyways can be formed in the core body, but the core body must be made of high-strength material to maintain structural strength
Solution Approach 1:
The through holes are segmented into two parts: a first portion extending from the first end surface towards the second end surface, and a second portion extending from the second end surface towards the first end surface. These segments meet or overlap at different positions along the central axis, avoiding a complete through-hole that would compromise structural integrity while still enabling keyway formation.
2Ease of manufacture
If the through holes extend through the central axis, then the pins can be mounted in the core body, but it becomes difficult to form recesses in the inner helical surface of the helical blades
Solution Approach 1:
The recesses are formed on the outer peripheral surface of the helical blades rather than on the inner helical surface. This dimensional change from internal to external surface makes the recess formation process significantly easier while maintaining the functional relationship between the pins and helical blades.
3Reliability
If the through holes extend through the central axis, then the lock mechanism can function, but the lock becomes easier to pick
Solution Approach 1:
The asymmetric configuration of the segmented through holes and the positioning of the pins create a more complex interaction geometry between the key and lock components. This asymmetry increases the difficulty of picking by requiring precise geometric matching rather than allowing simple manipulation.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A lock (100) includes a housing (2), a cylindrical core body (3) and a tumbler unit (4). The core body (3) is rotatably mounted in the housing (2), and includes a core axle (32), and a core tube (33) sleeved on the core axle (32). The core axle (32) has a helical keyway (323) . The tumbler unit (4) includes a housing pin hole (41) formed in the housing (2), a tube through hole (42) formed through the core tube (33), a pin assembly (43) movably mounted in the housing pin hole (41) and the tube through hole (42), a hole-defining surface (44) defining the tube through hole (42) and having a shoulder surface portion (441), and a resilient member (45) disposed in the housing (2) and resiliently biasing the pin assembly (43) to abut against the shoulder surface portion (441) and extend into the helical keyway (323) .