Cistern Connection Piece Anti-Rotation Housing

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Solution Overview

Problem

Existing cistern designs face challenges in securely fixing the connection piece against rotation relative to the cistern wall, leading to complex machining requirements, increased material costs, and potential stress on plastic components due to torsional forces during flushing water line fastening.

Innovation Solution

A cistern design featuring a connection piece with radial projections and a housing consisting of two interlocking halves, which provide a form-fitting, twist-proof and axially fixed mounting, along with a sleeve and flange area for secure attachment to the cistern wall, utilizing a union nut for additional fixation and distributing torsional forces effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the connection piece is made with hexagonal outer contour and hexagonal opening in the flange part to prevent rotation, then the connection piece is secured against rotation relative to the cistern wall, but the machining complexity of the connecting piece increases significantly

Engineering Contradiction:
Improveanti-rotation securityVSAvoidmachining complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses asymmetric key-shaped projections with specific geometric features (flat sides, rounded corners, varying lengths) that mate with corresponding asymmetric receptacles in the housing halves. This asymmetric design provides reliable anti-rotation security while being manufacturable through standard injection molding processes for the plastic housing and simple machining or molding for the brass connection piece.

Inventive Principle:
Principle #4Asymmetry

2Strength

If the dimensions of the connecting piece are increased to ensure sufficient strength during power transmission, then the strength during torsional loading is improved, but the material requirements and costs increase

Engineering Contradiction:
Improvestrength during power transmissionVSAvoidmaterial requirements
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The patent segments the force transmission path by introducing key-shaped projections that concentrate torsional forces at specific localized contact points between the connection piece and housing halves. This segmentation allows the connection piece to maintain sufficient strength during power transmission while using less material, as the forces are distributed to multiple discrete engagement points rather than requiring uniform thickening of the entire component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by providing reinforced geometric features (key-shaped projections with specific cross-sectional areas) only at the critical locations where force transmission occurs. The connection piece has varying thickness and reinforcement only where needed for torque transmission, rather than uniformly increasing dimensions throughout the entire component, thus reducing overall material requirements while maintaining necessary strength.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If the housing is made of plastic to match the cistern wall material, then the overall cistern construction is simplified and costs are reduced, but the housing may not adequately absorb torsional forces without exceeding permissible surface pressure

Engineering Contradiction:
Improvecistern construction simplicityVSAvoidtorsional force absorption
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent segments the torsional force absorption function by dividing the housing into two separate housing halves that can be positively connected to each other. This segmentation allows the plastic housing to adequately absorb torsional forces through the combined strength of both halves working together, while maintaining the simplicity of plastic construction and matching the cistern wall material.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges the strength contribution of two housing halves working together to achieve sufficient torsional force absorption. The two plastic housing halves are designed to be positively connected, combining their structural capacity to handle torsional loads while exceeding the permissible surface pressure requirements through their combined strength rather than requiring a single oversized plastic component.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If at least two components are used to axially secure the sealing body in the double nipple, then the axial fixation is reliable, but the device complexity increases

Engineering Contradiction:
Improveaxial fixation reliabilityVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into a single integrated housing structure that provides both axial fixation and anti-rotation security for the connection piece. The housing halves with their positive connection features simultaneously achieve reliable axial positioning and prevent rotation, eliminating the need for separate axial securing components and reducing overall device complexity while maintaining reliability.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2460943B1Flushing cistern
Publication Date: 2015.08.26 GROHEDAL SANITARSYSTEME GMBH
  • EP2460943B1 patent drawingFigure 1
  • EP2460943B1 patent drawingFigure 2
  • EP2460943B1 patent drawingFigure 3

AI summary

The cistern has a connection piece (1) provided for inner and outer rinsing water inflow lines and arranged in an aperture of a cistern wall. A housing enables fixation of the connection piece in the cistern wall, where the connection piece is axially fixed and rotationally mounted in the housing. The housing comprises housing halves (21) positively connected with one another. The housing or the housing halves comprises a case region (214) and a flange region (215). Complementary half shells are provided for the housing. An external thread is provided in the case region.