Door Handle Limiter Integrated With Chain Lock Security

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Traditional door chain locks cannot restrict the use of the door handle, leaving security gaps despite their ability to limit the door's opening angle.

Innovation Solution

A door handle limiter comprising a latch component, lock hook, and chain, which is connected to a door chain lock, prevents the door handle from being pushed down by latching onto the inner door handle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional door chain lock is used, then the door opening angle can be limited, but the door handle cannot be restricted from being pushed down

Engineering Contradiction:

ImprovesecurityVSAvoidhandle restriction capability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent combines the door chain lock function with a door handle limiter function into a single integrated device. The limiter component is attached to the chain lock, and its latch engages with the door handle to prevent it from being pushed down, while the chain lock continues to limit the door opening angle. This merging resolves the contradiction by making the security device versatile enough to restrict both door opening and handle operation.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The door chain lock is enhanced with additional functionality through the attached limiter component. The limiter's latch specifically engages with the door handle to prevent pushing down, while the main body integrates with the chain lock structure. This multi-functionality allows a single device to perform both angle limitation and handle restriction, resolving the security gap in traditional chain locks.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of operation

If a door chain lock without key is used, then convenience is improved, but security against unauthorized access is weakened

Engineering Contradiction:

Improvekeyless operationVSAvoidanti-theft capability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The limiter component is pre-configured with a latch that automatically engages with the door handle when the chain lock is installed. This preliminary anti-action prevents the handle from being pushed down before any attempted intrusion occurs. The spring mechanism ensures the latch is always in the blocking position, providing continuous security enhancement without requiring additional keys or complex operations.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The limiter acts as an intermediary component between the chain lock and the door handle. It mediates the interaction by physically blocking the handle's downward movement through the latch engagement, while maintaining the keyless operation convenience of the original chain lock. This intermediary structure enhances security without compromising ease of use.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20260043273A1Door handle limiter

Publication Date: 2026.02.12 SHOPIN LOCK

AI summary

A door handle limiter includes a latch component including a latch part, a lock hook, and a chain. The chain has a first end thereof connected to the latch component, and a second end of the chain is connected to the lock hook. The user simply needs to hook the lock hook onto the chain of the door chain lock and then latch the latch component onto the end of the inner door handle. This prevents the door handle from being pushed down.