Stroller Joint Connecting Structure That Prevents Bolt Loosening

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Solution Overview

Problem

Current foldable strollers face issues with joint connections that allow rotational torque, leading to loosening of bolts and nuts, and lack a compact locking mechanism that conceals these components, affecting user experience and structural integrity.

Innovation Solution

A connecting structure with a spacer member and locking mechanism that prevents rotational torque by spacing the joint components apart, using a screw-like member fixed to one joint and a spacer that cannot rotate, ensuring secure and concealed joint connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional bolt and nut connection is used to connect joint components, then the joint can be assembled, but the rotational torque causes the bolts and nuts to loosen over time

Engineering Contradiction:
Improvejoint connection stabilityVSAvoidbolt and nut tightness
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent extracts the harmful rotational torque transmission path by spacing the connecting member away from the second joint component. The spacer member creates a gap that prevents the connecting member from contacting the second joint component, thereby eliminating the torque that would otherwise cause loosening of the bolt-nut connection.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The spacer member acts as an intermediary element between the connecting member and the second joint component. It introduces a deliberate gap that mediates the interaction, preventing direct contact and the subsequent harmful rotational torque while still allowing the joint to function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If the connecting member is positioned close to the second joint component for compactness, then the structure is more compact, but rotational torque is generated causing loosening

Engineering Contradiction:
Improvejoint connection compactnessVSAvoidjoint connection stability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The spacer member serves as an intermediary that deliberately creates spacing between the connecting member and the second joint component. This spacer is a non-rotating element that prevents torque transmission while maintaining a controlled, compact arrangement of the joint components.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the connecting member contacts the second joint component directly, then the locking mechanism is simpler, but the appearance is messy and the connection is less secure

Engineering Contradiction:
Improvelocking mechanism complexityVSAvoidjoint connection appearance
Core Design Contradiction:
Device complexityVSShape

Solution Approach 1:

The patent removes the direct contact between the connecting member and the second joint component by introducing a spacer. This extraction of the harmful contact point eliminates the messy appearance and insecure connection while the overall structure remains relatively simple.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4613609A1Connecting structure, child carrying device, frame, and child carrier
Publication Date: 2025.09.10 WONDERLAND SWITZERLAND AG
  • EP4613609A1 patent drawingFigure 1
  • EP4613609A1 patent drawingFigure 2A~2B
  • EP4613609A1 patent drawingFigure 3A~3B

AI summary

A connecting structure is provided, including: a first joint component and a second joint component pivotable relative to each other around an axial direction; and a connecting member extending through the second joint component in the axial direction and inserted into and screwedly connected to the first joint component to restrict a separation of the first joint component from the second joint component in a direction parallel to the axial direction. The connecting member is spaced apart from the second joint component.