U-Shaped Window Profile Connector With Variable Cam Radius Friction Claws

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Solution Overview

Problem

Existing plug-in joining members for window frame profiles, particularly hollow profiles for glass panel struts, face issues with reliable and efficient fixation due to uneven friction distribution and potential deformation, leading to unreliable connections.

Innovation Solution

A plug-in joining member with an elongated U-shaped cross-section featuring friction claws with gradually increasing cam radii towards the central line, uniform stiffness, and strategically placed beadings, ensuring consistent friction and resistance across all claws for stable fixation within hollow profiles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If friction claws are arranged with uniform cam radius, then manufacturing is simplified, but fixation reliability deteriorates due to uneven friction distribution and potential deformation

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidfixation reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by varying the cam radius of individual friction claws according to their position. Friction claws closer to the center have larger cam radii while those at the ends have smaller cam radii. This localized differentiation compensates for the stiffer behavior of central claws and ensures uniform friction distribution across all claws, resolving the contradiction between manufacturing simplicity and fixation reliability.

Inventive Principle:
Principle #3Local quality

2Reliability

If friction claws have different stiffness, then fixation reliability improves through better adaptation, but device complexity increases due to varied manufacturing requirements

Engineering Contradiction:
Improvefixation reliabilityVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements local quality by positioning friction claws at different distances from the neutral axis of the U-shaped profile. Claws closer to the center are positioned farther from the neutral axis while end claws are positioned closer. This creates different stiffness characteristics for each claw location, allowing better adaptation to local conditions and improving fixation reliability without requiring complex varied manufacturing processes.

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If friction claws are positioned at different elevations, then deformation prevention improves, but manufacturing precision requirements increase

Engineering Contradiction:
Improvedeformation preventionVSAvoidelevation precision
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent applies the curvature principle by designing friction claws with cam-shaped profiles rather than straight profiles. The cam radius varies systematically from smaller values at end claws to larger values at central claws. This curved geometry allows the claws to engage the profile walls at optimized angles and positions, preventing deformation while maintaining manufacturability through standardized cam formation processes.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

The design enhances the reliability and durability of the fixation by maintaining uniform adhesion and resistance, preventing deformation and slip during insertion, while allowing for easier tolerance adjustments and consistent holding action across all friction claws.

Implementation Method 1

The side walls are provided with friction claws, where the friction claws at the both sides are turned towards the central line of the joining member

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3730732B1Plug connector for connecting ends of window profiles
Publication Date: 2021.11.10 GRZYWACZ CEZARY
  • EP3730732B1 patent drawingFigure 1~2
  • EP3730732B1 patent drawingFigure 3~4
  • EP3730732B1 patent drawingFigure 5~6

AI summary

Plug-in joining member (1) designed to make connections between ends of window frame profiles is formed as an elongated piece with nearly U-shaped cross-section and comprising a bottom wall (2) and side walls (3) adjacent to the bottom wall (2) down its side edges. Side walls (3) of the joining member (1) are provided with friction claws (4), arranged at the both sides of the central line (O) and turned towards the central line (O) of the joining member (1). The joining member (1) also has at least one central stop (5, 5'). Cam radiuses R1, R2, R3, R4 in working portions (4A) of each subsequent friction claw (4) on a specific side wall (3) gradually increase from each far end of the joining member (1) towards the central line (O) of the joining member (1), whereas tips (7) of working portions (4A) of friction claws (4), after having them bent out to working positions, are arranged at the same elevations above the bottom wall (2). Preferably, uniform stiffness of all friction claws (4) is maintained and tips (7) of working portions (4A) of friction claws extend outwardly to the same distance with reference to the longitudinal central axis (O1) of the joining member (1).