Espagnolette Guide Pin Hook and Bearing Surface Design
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Solution Overview
Problem
Existing window and door locking mechanisms experience high wear and instability due to shear stresses on guide pins and pivot axes under operating forces.
Innovation Solution
The guide pin features a hook that engages behind a projection of the guide groove's undercut, allowing it to absorb tensile forces and avoid shear stresses, while the pivot axis is supported by a counter-bearing surface, reducing wear and stabilizing the closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the guide pin is arranged in a straight line with the bearing axis and support surface, then the structure is simple, but shear stresses are introduced into the guide pin causing high wear and instability
Solution Approach 1:
The guide pin is designed with an asymmetric hook shape at its free end, which engages behind a projection of the guide groove to form an undercut. This asymmetric geometry allows the guide pin to absorb tensile forces while avoiding shear stresses, resolving the contradiction between structural simplicity and reliability
Solution Approach 2:
Instead of arranging the guide pin, bearing axis, and support surface in a straight line (conventional design), the invention inverts the force transmission path by positioning the pivot axis and support surface to create a moment arm. This inversion transforms shear stress into tensile force absorption, improving reliability while maintaining acceptable structural complexity
2Force
If the pivot axis supports the locking element in the protruding position, then operating forces are largely supported by the pivot axis, but this increases wear on the pivot axis
Solution Approach 1:
The hook on the guide pin acts as an intermediary element that transfers operating forces from the locking element to the coupling element. By engaging behind the guide groove projection, the hook creates a force transmission path that bypasses the pivot axis, reducing wear while maintaining load bearing capacity
Solution Approach 2:
The invention introduces a moment arm dimension by positioning the support surface and pivot axis at different locations. This dimensional change allows forces to be transmitted through a lever arm mechanism rather than directly through the pivot axis, reducing wear on the pivot axis while maintaining force support capability
Data Source
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AI summary
In a locking device (6) for a drive rod fitting (3) with a pivotable locking element (12) having a guide groove (17), a guide pin (16) has a hook (20) with which it engages a projection (21) of the guide groove (17). Furthermore, bearing surfaces (22, 23) are arranged next to a pivot axis (19) of the locking element (12). Operating forces of the locking device are transferred via the hook (20) and the bearing surfaces (22, 23). This keeps the load on the pivot axis (19) low.