Openable Captive Eye Hook for Replaceable Fall Protection Lanyards

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Solution Overview

Problem

Existing snap hooks in personal fall protection systems require the entire system to be discarded when the lanyard is deployed, lacking reusability and efficient lanyard replacement mechanisms, and do not provide sufficient safety features.

Innovation Solution

A rebar or snap hook with an openable captive eye mechanism featuring a one-way gate that allows the hook to be reused by opening from one end, enabling easy lanyard replacement and incorporating a dismountable gate mechanism for enhanced safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the lanyard is permanently stitched to the eye of the hook, then the connection is secure and reliable, but the entire system must be discarded when the lanyard is deployed and cannot be replaced on site

Engineering Contradiction:
Improveconnection reliabilityVSAvoidlanyard replaceability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The eye is segmented into a fixed portion and a movable gate portion that can be opened and closed. The gate can be opened to remove or replace the lanyard, and closed to secure it, allowing the hook to be reused after lanyard replacement while maintaining secure connection when closed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The gate is designed to be dynamically openable and closable, transitioning between locked and unlocked states. This dynamic capability allows the eye to adapt between securing the lanyard firmly and allowing its removal or replacement, resolving the contradiction between connection reliability and lanyard replaceability.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the gate is made openable to allow lanyard replacement, then the hook becomes reusable, but the safety and security of the connection may be compromised

Engineering Contradiction:
Improvelanyard replaceabilityVSAvoidconnection security
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The gate mechanism includes self-latching features with spring-loaded pins and recesses that automatically engage when the gate is closed, providing self-service locking without requiring additional fastening steps. This ensures the gate remains securely closed during use while allowing intentional opening for lanyard replacement.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The gate is designed to be temporarily opened only when necessary for lanyard replacement, then securely closed and recovered for continued use. The mechanism ensures that once closed, the gate maintains secure connection equivalent to or better than permanent stitching, allowing the hook to be recovered and reused.

Inventive Principle:
Principle #34Discarding and recovering

3Reliability

If a complex lock mechanism is added to secure the openable gate, then the safety is enhanced, but the device complexity increases

Engineering Contradiction:
Improvetamper-proof protectionVSAvoidgate mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking function is extracted as a separate self-latching mechanism distinct from the gate structure itself. Spring-loaded pins and recesses are integrated into the gate and frame, providing automatic locking without requiring complex external locking components, thus enhancing security while minimizing added complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The gate mechanism merges multiple functions into a single integrated assembly: the gate itself serves as both the opening/closing element and part of the locking mechanism through integrated pins and recesses. This combining of functions provides tamper-proof protection without proportionally increasing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

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

Enables the reuse of the snap hook by allowing easy lanyard replacement and provides tamper-proof protection, ensuring user safety and reducing waste.

Implementation Method 1

self-latching by means of a spring-loaded pin locating in a recess of the arm and having a cap to enable the pin to be withdrawn to open the karabiner

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

a pivoted arm which is biased to close the loop and which is self-latching by means of a spring-loaded pin

Methodology Applied
Scientific EffectSpring action: Spring

Data Source

PatentEP4051916B1Personal fall protection device with openable captive eye and lock mechanism
Publication Date: 2025.12.03 KARAM SAFETY PVT LTD
  • EP4051916B1 patent drawingFigure 1
  • EP4051916B1 patent drawingFigure 2
  • EP4051916B1 patent drawingFigure 3(a)~3(b)

AI summary

The present invention relates to a personal fall protection system with openable captive eye (100) and lock mechanism to enable strong and safe locking. The hinged gate (106) includes an internal cavity (105), connected to the posterior end (103) of the hook body (101) via fastening means (104). The one- way blocker and a conical seat (108) are in the anterior end (107) of the hook body (101). The captive eye (200) of the hook is opened from one of the ends by hinged gate (106) to insert the lanyard and the tightening means (109) is fitted in the internal cavity (105) of the hinged gate (106) to latch the hook. The gate and lock are spring operated and designed in a way that restricts opening of the gate.