Permanent Formwork Modules With Screw-Assembled Half-Spacers

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Solution Overview

Problem

The existing lost formwork elements for concrete swimming pool walls require manual welding of half-spacers, leading to high manufacturing costs and variability in weld quality, which can result in structural disorders and deformation under concrete pressure, affecting the wall's flatness and mechanical strength.

Innovation Solution

The use of modules with half-spacers featuring proximal bores for screw assembly, providing high mechanical resistance and rigidity, allowing assembly by unskilled personnel with a screwdriver, and enabling unassembled module storage with reduced footprint, while minimizing material perforation and oxidation risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If manual welding is used to assemble half-spacers, then the formwork element can be constructed, but the manufacturing cost increases and weld quality becomes variable

Engineering Contradiction:
Improveassembly processVSAvoidweld quality consistency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the welding process (thermal/chemical system) with a mechanical screw assembly system. The half-spacers are equipped with proximal bores that receive assembly screws, transforming the joining mechanism from welding to mechanical fastening. This substitution eliminates weld quality variability while maintaining structural integrity, as screws provide consistent mechanical connection without the complexities of weld procedure control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If welding is used to join half-spacers, then the modules can be assembled, but the labor cost and manufacturing complexity increase

Engineering Contradiction:
Improveassembly speedVSAvoidassembly process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The half-spacers are designed with self-aligning proximal bores that guide the assembly screws directly into position. This self-service feature eliminates the need for complex welding fixtures or specialized equipment, allowing unskilled personnel to assemble the modules using only a screwdriver or electric screwdriver. The design inherently provides alignment and positioning functions that would otherwise require complex external tools.

Inventive Principle:
Principle #25Self-service

3Strength

If welding is used to ensure structural strength, then the formwork can withstand concrete pressure, but the risk of deformation under pressure increases due to weld variability

Engineering Contradiction:
Improveformwork mechanical strengthVSAvoidwall flatness
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent changes the joining parameter from weld penetration depth and temperature control to screw insertion depth and tightening torque. The assembly screws engage with threaded portions in the proximal bores, providing controlled mechanical fastening with precise engagement parameters. This parameter change ensures consistent clamping force distribution across all half-spacers, preventing localized deformations that could compromise wall flatness under concrete pressure.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If modules are delivered pre-assembled to ensure quality, then the assembly quality improves, but the storage volume and delivery cost increase

Engineering Contradiction:
Improveassembly qualityVSAvoidstorage volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent segments the formwork system into modular panels with integrated half-spacers that are designed for easy field assembly. Each panel is self-contained with the necessary joining features (proximal bores in half-spacers), allowing quality control at the panel manufacturing stage while maintaining compact storage. The segmentation enables panels to be stored in a nested or stacked configuration with reduced footprint compared to fully pre-assembled structures.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP1749951B1Permanent formwork element and module for building such an element
Publication Date: 2009.07.15 TOUT POUR LEAU PRAT
  • EP1749951B1 patent drawingFigure 1
  • EP1749951B1 patent drawingFigure 2
  • EP1749951B1 patent drawingFigure 3

AI summary

The module has a set of semi-cross-bars (20) distributed on a back side (5) of a rectangular panel (3) by extending perpendicular to the panel. The semi-cross-bars are placed in four rows parallel to an upper edge of the panel. Each semi-cross-bar has a male and/or female embedding element at the level of its distal end for engagement in a complimentary embedding element of a corresponding semi-cross-bar during the assembly of the module with another module. The semi-cross-bars have a proximal bore (22) receiving an assembling screw and emerge out at the level of a front side (4) of the panel. An independent claim is also included for a permanent formwork element comprising two identical modules embedded with each other at the level of their semi-cross-bars and assembled by a set of screws engaged by a set of screws engaged in proximal bores of embedded semi-cross-bars.