Dual Lock-Pin Ladder Hinge for Fast Closure and Stronger Locking

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Solution Overview

Problem

Existing ladder hinges with dual locking pins suffer from complex structures, excessive parts, slow closure, and insufficient strength, particularly lacking a reliable mechanism to hold the hinge in an unlocked state.

Innovation Solution

The design incorporates an outer and inner hinge member with a pivot and a locking device featuring lock-pins with holding grooves and inclined arc surfaces, allowing the hinge to securely hold the outer shell in an unlocked state and prevent excessive rotation, along with reinforcing ribs for enhanced strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional dual locking pin mechanism is used, then locking function is achieved, but structure becomes complicated and operation becomes slow

Engineering Contradiction:
Improvelocking functionVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the locking pin and holding groove into a single integrated component. The locking pin serves dual functions: it provides the locking function when engaged with the locking aperture, and simultaneously provides the holding groove to maintain the unlocked state. This merging eliminates the need for separate components, simplifying the overall structure while maintaining reliable locking and unlocking operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The locking pin is designed with multi-functionality. It not only performs the primary locking function by engaging with the locking aperture, but also provides the holding groove that serves as a stop to prevent excessive rotation and maintain the unlocked state. This universal design allows a single component to fulfill multiple functions, reducing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If traditional dual locking pin mechanism is used, then locking function is achieved, but closure speed becomes slow

Engineering Contradiction:
Improvelocking functionVSAvoidclosure speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The holding groove is pre-formed on the locking pin, creating a predetermined stop position before the locking aperture. During the closing operation, the outer hinge shell is guided into the holding groove first, establishing the unlocked state with a defined stop position. This preliminary action ensures that the hinge is properly positioned before locking occurs, enabling quick and smooth closure without delays.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If traditional dual locking pin mechanism is used, then locking function is achieved, but strength becomes insufficient

Engineering Contradiction:
Improvelocking functionVSAvoidhinge strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The holding groove is designed with a curved or arc-shaped cross-section that matches the curvature of the locking pin. This spherical or curved geometry distributes the contact stress more evenly across the contact surface, increasing the strength of the connection. The curved surface allows for better load distribution and reduces stress concentration, thereby enhancing the overall strength of the hinge mechanism.

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

This configuration simplifies the locking mechanism, enables quick operation, and significantly enhances the strength of the ladder hinge by ensuring the lock-pins maintain the hinge in an unlocked state during closure and prevent excessive rotation, improving overall functionality and safety.

Implementation Method 1

a compression spring (42) disposed outside the outer hinge member (1) with two ends thereof biasing the pivot (3) and the push knob (41), respectively

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the inclined arc surface presses against the second inner hinge shell to prevent the second outer hinge shell at the peripheries of the lock-holes from departing the holding grooves

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3581755B1Ladder hinge with dual lock-pins
Publication Date: 2021.04.07 YEH KANG SHUO
  • EP3581755B1 patent drawingFigure 1
  • EP3581755B1 patent drawingFigure 2
  • EP3581755B1 patent drawingFigure 3~4

AI summary

A ladder hinge with dual lock pins includes an outer hinge member, an inner hinge member, a pivot, and a locking device; the outer hinge member provides two opposite lock-holes; the inner hinge member provides three pairs of locating holes; the pivot joins the outer and inner hinge members; the locking device consists of a push knob, a compression spring, and a lock-pin assembly; the lock-pin assembly further has a handle, a linking shaft, and two lock-pins; the lock-pins each have a holding groove disposed near the free ends thereof to achieve the unlock state; the free ends of the lock-pins each are provided with an inclined arc surface at the back of the holding grooves for keeping the ladder hinge at unlocked state during the ladder hinge being closed.