Installation Box Membrane with Eccentric Tear Handle

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Solution Overview

Problem

Existing cavity wall boxes require manual tearing of a soft plastic membrane to open pipe entries, which can lead to uncontrolled crack formation and compromised windproofness when inserting installation pipes, especially corrugated hoses, due to the need for manual force application and potential misalignment of tear initiation.

Innovation Solution

The design features a soft plastic membrane with a tearing handle that has a concave curvature and is offset eccentrically, using a material thinning as the tearing contour, which limits crack propagation and ensures a defined tear initiation along the contour, allowing for easier and more controlled insertion of installation pipes while maintaining windproofness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a soft plastic membrane with a straight tear-off handle is used, then the membrane can be torn to open pipe entries, but uncontrolled crack propagation occurs compromising airtightness

Engineering Contradiction:
Improveease of opening pipe entryVSAvoidairtightness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The tear-off handle is designed with concave curvature instead of being straight. This curved geometry guides the tear propagation along a controlled path, preventing uncontrolled cracking while maintaining ease of opening the pipe entry.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The membrane structure is made non-uniform by introducing a material thinning at the tear contour location. This local variation in material thickness creates a preferred tear path that limits crack propagation, while the rest of the membrane maintains its original thickness and airtightness properties.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If manual force is applied to tear the membrane, then the pipe entry can be opened, but crack initiation becomes uncontrolled

Engineering Contradiction:
Improveease of opening pipe entryVSAvoidtear initiation precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The material thinning is pre-formed at the desired tear contour location during manufacturing. This preliminary preparation creates a predetermined weak point that initiates tearing at the exact desired location when force is applied, ensuring precise and controlled crack initiation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The concave curvature of the tear-off handle guides the application of manual force along a specific arc, which in turn directs the tear initiation and propagation along a controlled path, improving precision of tear location.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Reliability

If the tear contour is defined by material thinning, then crack propagation is limited, but the structure becomes more complex

Engineering Contradiction:
ImproveairtightnessVSAvoidmembrane structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The material thickness parameter is varied locally at the tear contour region instead of changing the overall membrane structure. This subtle parameter change creates the desired tear control function while maintaining the simplicity of the single-piece molded membrane structure.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design simplifies the handling and insertion process of installation pipes by ensuring a clean, defined tear and preventing radial crack formation, thereby maintaining windproofness and ensuring secure engagement of the pipe within the membrane.

Implementation Method 1

a material thinning is provided as the tear contour (13) which limits the propagation of cracks during tearing

Methodology Applied
Scientific EffectCrack propagation control through material thinning: Fracture Mechanics

Implementation Method 2

Each pipe entry (22) is covered with a soft plastic membrane (7), so that it is closed when not in use

Methodology Applied
Scientific EffectElastic deformation of soft plastic membrane: Elasticity

Data Source

PatentEP3703206B1Installation box and installation unit with such an installation box and installation pipe
Publication Date: 2021.06.30 OBO BETTERMANN HUNGARY KFT
  • EP3703206B1 patent drawingFigure 1~2
  • EP3703206B1 patent drawingFigure 3~4
  • EP3703206B1 patent drawingFigure 5~6

AI summary

An installation box 1 for electrical/electronic installations comprises a box body 2 for receiving at least one electrical/electronic component. This box body has a base 4, a surrounding wall 3, and a mounting opening 5. The box body 2 has at least one pipe entry covered by a soft plastic membrane 7, 7.1 for inserting the end section of an installation pipe. The soft plastic membrane 7, 7.1 has, at the position provided for pipe entry, a bead 8, 8.1 formed by material thickening and a tear zone 10, 10.1 enclosed by a tear contour 13, 13.1, with a cross-sectional area smaller than the cross-sectional area of ​​an installation pipe 14 to be inserted therein. The tear zone 10, 10.1 has a tear handle 9, 9.1 for removing the tear zone 10, 10.1. The tear-in handle 9, 9.1 is designed with a concavely curved actuating surface 11 for receiving a tearing force acting transversely to the tear contour 13, 13.1 for tearing, wherein the actuating surface 11 of the tear handle 9, 9.1 is arranged eccentrically with respect to the direction of the force direction intended for tearing onto the tear area 10, 10.1 and the tear handle 9 extends to the area of ​​the tear contour 13, 13.1.