Tunnel Box Groove Segmentation for Structural Rigidity
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Solution Overview
Problem
Conventional tunnel boxes with grooves for receiving fixing lugs suffer from reduced rigidity due to thinner walls and potential rod oxidation, which can damage roller shutter slats, and lack effective reinforcement to securely anchor with carpentry frames.
Innovation Solution
A tunnel box design featuring a groove with a notch that interrupts before the free edge, allowing an enlarged volume for rods, combined with additional rods and profiles to enhance structural rigidity, and a fixing lug system that connects the lintel and frame, maintaining comparable rigidity to conventional designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a groove is hollowed out in the arch wall or jamb wall to insert a fixing lug, then the fixing connection between lintel and frame is improved, but the wall thickness is reduced and structural rigidity deteriorates
Solution Approach 1:
The groove is segmented into two parts: a first groove portion extending from the outer face toward the inner face, and a second groove portion extending from the outer face at a different location. This segmentation allows the groove to be interrupted before reaching the inner face, maintaining wall thickness and rigidity while still providing adequate space for fixing lug insertion and connection.
Solution Approach 2:
The groove geometry is optimized locally: the first groove portion has a depth adapted to receive the fixing lug, while the groove is intentionally interrupted before reaching the inner face. This local quality adjustment ensures sufficient fixing capability while preserving the overall structural rigidity of the tunnel box.
2Strength
If rods are placed close to the faces of the jamb wall, then the structural reinforcement is improved, but rod oxidation and damage to roller shutter slats occur
Solution Approach 1:
A groove is introduced as an intermediary element between the rod and the inner face of the tunnel box. The groove accommodates the rod at an optimal position for structural reinforcement while maintaining sufficient distance from the inner face to prevent oxidation and roller shutter slat damage. The groove acts as a mediating structure that resolves the conflict between reinforcement effectiveness and protection against harmful effects.
3Ease of manufacture
If the groove extends to the free edge of the side wall, then the fixing lug insertion is simplified, but the volume of material is reduced and rigidity deteriorates
Solution Approach 1:
The groove is segmented into a first groove portion and a second groove portion, with the first portion providing adequate space for fixing lug insertion and the groove being interrupted before reaching the free edge. This segmentation maintains sufficient material volume for rigidity while still enabling practical fixing lug installation.
Solution Approach 2:
The groove extends partially toward the free edge but is intentionally interrupted before reaching it. This partial action provides sufficient space for fixing lug insertion without the excessive extension that would compromise structural rigidity and material volume.
Data Source
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AI summary
The present invention relates to a tunnel box (100) intended to house a window or door shutter mechanism, the tunnel box (100) being designed to be anchored above a reveal defining the frame for installing a window or door sash, the tunnel box (100) comprising an arch wall (V) extended by at least one edge, a side wall (L1, L2), a groove (110) cut from the outside of said side wall (L1) and/or the arch wall (V), said groove being intended to house a fixing/reinforcing bracket (200), said tunnel box incorporating a reinforcing frame (130) of its structure, comprising hoops (132) arranged radially within the material of said tunnel box, and rods (136) arranged longitudinally within the material of said tunnel box. so as to join the said hoops.According to the invention, the groove (110) is delimited by a notch (110a) which is interrupted before the free edge of the side wall (L1), creating an enlarged volume (M) of material in the lower part of the side wall (L1) in which at least one rod (136a) is located. Although locally thinner, the side wall of the tunnel box of the invention nevertheless incorporates a rod which, connected to a plurality of hoops, significantly increases the rigidity of the tunnel box. This increased stiffness can be used to rigidly secure the side wall of the tunnel box to a frame of a window or door.