Espagnolette Rod Tool-Free Assembly via Cardanic Joint
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Solution Overview
Problem
Existing fixed leaf locks for doors require high accuracy in insertion openings, leading to misalignments and increased manufacturing costs due to complex assembly processes and additional openings for tool access, making them expensive and difficult to assemble reliably.
Innovation Solution
A two-part espagnolette rod design with a cardanic configuration allows tool-free assembly, compensating for misalignments through a non-positive connection between the screw and ball bushing, and a cone bushing, eliminating the need for additional openings and simplifying production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed leaf locks are assembled with traditional screw connections requiring tool access through openings, then reliable connection is achieved, but manufacturing costs increase and assembly complexity increases
Solution Approach 1:
The espagnolette rod is divided into two separate sections that are assembled together without tools. The first section contains the locking mechanism housing, while the second section contains the espagnolette bolt. These sections connect through a cardanic joint with ball bushings, eliminating the need for traditional screw fastening and tool access openings.
Solution Approach 2:
The ball bushings are nested within the cardanic joint structure, with the first ball bushing received by the screw in a non-positive connection and the second ball bushing receiving the second section of the espagnolette rod. This nested arrangement enables tool-free assembly while maintaining reliable connection.
2Ease of manufacture
If insertion openings for lock housing, espagnolette rod bore, and guide sleeve bore are made independently, then manufacturing flexibility is improved, but misalignments occur between guide sleeve and espagnolette rod
Solution Approach 1:
The cardanic joint design changes the geometric parameters of the connection, allowing angular adjustment and compensation for misalignments between independently manufactured components. The ball bushings enable rotational movement that accommodates variations in bore positioning while maintaining functional alignment.
3Ease of manufacture
If additional opening is made on forend for tool access, then screw connection is enabled, but manufacturing costs increase
Solution Approach 1:
The screw connection method is extracted and replaced with a tool-free ball bushing-based cardanic joint assembly. This eliminates the need for additional openings on the forend for tool access, thereby reducing manufacturing costs while maintaining assembly capability.
4Productivity
If fitter mounts fixed leaf lock without clear view, then installation is completed, but assembly time increases and skill requirement increases
Solution Approach 1:
The cardanic joint with ball bushings is designed to assemble itself without tools or complex alignment procedures. The non-positive connection of the first ball bushing by the screw and the positive engagement of the second ball bushing enable intuitive, tool-free assembly that does not require fitter skill or clear viewing access.
Data Source
Figure 1
Figure 2
Figure 3~6
AI summary
The interlocking device (1) has a locking rod (60) which stands in work connection with a lock mechanism with a section at an end. The locking rod is engaged with another section with an end in an opening of a door frame. The former section of the locking rod is connected with the latter section of the locking rod without tools.