Door Latch Assembly with Movable Extension for Ajar Positioning

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Solution Overview

Problem

Existing door latch assemblies are inadequate in maintaining a door in a fixed ajar position, leading to poor air circulation and inadequate exclusion of pets and small children, as they lack enhanced functionality to secure the door effectively.

Innovation Solution

A door latch assembly comprising a base member with a striker plate portion and an extension member, which can be attached to a conventional door jamb, allowing the door to be securely held in an ajar position using a locking mechanism that includes a key and teeth for secure alignment and support, while being easily removable for normal door operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional door latch structure is used, then the door can be closed and locked, but it cannot maintain a fixed ajar position effectively

Engineering Contradiction:

Improvedoor position maintenance capabilityVSAvoiddoor position stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The door latch assembly incorporates a movable extension member that can transition between retracted and extended positions, allowing the latch to adapt to different door positions (closed or ajar) while maintaining stability in each position through the locking mechanism with teeth and key

Inventive Principle:

Principle #15Dynamics

2Productivity

If the door is held ajar to improve air circulation, then air circulation improves, but pets and small children can still access restricted areas

Engineering Contradiction:

Improveair circulationVSAvoidunauthorized access by pets and children

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The latch mechanism applies localized restraint at the door edge through the extension member and striker plate assembly, creating a barrier that prevents unauthorized access while leaving the rest of the door in an open position for air circulation

Inventive Principle:

Principle #3Local quality

3Reliability

If a more complex locking mechanism is added to secure the door in ajar position, then door position stability improves, but ease of operation deteriorates

Engineering Contradiction:

Improvedoor position stabilityVSAvoidlatch operation simplicity

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The extension member is designed to be self-aligning with the striker plate through the key and teeth geometry, allowing the latch to secure itself in the ajar position without requiring precise manual alignment or complex adjustment by the user

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS8376422B2Door latch assembly and methods of use thereof

Publication Date: 2013.02.19 SWINK KERRY

AI summary

A door latch assembly is attachable to a door jamb. The door latch assembly includes a base member and an extension member. The base member is mountable to the door jamb. The extension member is connectable to the base member such that the extension member extends from the base member. The extension member has a door stop member and a latch cup member. The door stop member is disposed substantially perpendicular to the latch cup member so that the door stop member provides a support for the door and the latch cup member receives a latch of the door so that the door is maintained in an ajar position.