Adjustable Self-Locking Latch-Bolt Lock Backset

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Solution Overview

Problem

Existing self-locking latch locks require multiple backsets to accommodate different door configurations, leading to complexity and high costs in manufacturing and inventory management, as they need to be changed internally to adjust for various backsets.

Innovation Solution

A self-locking latch lock design featuring telescopically adjustable right-angled shoulders and a latch arrangement with circumferential grooves and latching teeth, allowing for adjustment to different backsets without changing internal components, and incorporating a crank latch to prevent wear and ensure secure locking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple backsets are provided to accommodate different door configurations, then adaptability is improved, but device complexity and manufacturing costs increase

Engineering Contradiction:
Improveadaptability to different backsetsVSAvoidcomplexity of keeping multiple backsets in stock
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The latch arrangement is made dynamically adjustable through telescopic movement. The latch head can be positioned at different locations along the latch shaft, allowing the backset to be adjusted between 55mm and 65mm without changing the lock body. This dynamic adjustment capability eliminates the need to maintain multiple static backset versions in inventory.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The latch arrangement is segmented into separate components: latch head, latch shaft, and push element. This segmentation allows independent adjustment of the latch head position along the latch shaft, enabling backset adjustment without affecting other lock components. The modular design simplifies manufacturing and inventory management compared to providing complete separate backset assemblies.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If internal components are changed to adjust backsets, then adaptability is improved, but ease of manufacture and installation deteriorate

Engineering Contradiction:
Improveadjustability of backsetVSAvoidease of manufacturing and installing different backsets
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

A single universal lock body design accommodates multiple backset requirements through the adjustable latch arrangement. The lock case, faceplate, and actuating mechanisms remain unchanged, while only the latch head position needs adjustment. This multi-functional design allows one lock body to serve multiple door configurations, greatly simplifying manufacturing and installation processes.

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

Solution Approach 2:

The latch head is pre-configured with circumferential grooves that engage with latching teeth at specific positions along the latch shaft. This preliminary structuring of the adjustment mechanism allows for simple position selection during installation or adjustment, rather than requiring complex internal component changes. The adjustment can be performed by rotating the latch shaft to engage different groove positions.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If the latch is made adjustable for different backsets, then adaptability is improved, but reliability may deteriorate due to additional adjustment mechanisms

Engineering Contradiction:
Improveadjustability to different backsetsVSAvoidreliability of locking mechanism
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The latch arrangement includes a self-locking mechanism where the circumferential grooves on the latch shaft automatically engage with latching teeth at the selected position. Once the latch head is positioned at the desired backset location, the grooves and teeth provide automatic mechanical locking without requiring additional fasteners or adjustment procedures. This self-service locking feature maintains high reliability by using a simple, robust mechanical engagement system.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The adjustment mechanism uses simple, inexpensive elements such as circumferential grooves and latching teeth that are integral parts of the latch components. These features provide reliable positioning and locking without adding complex adjustable mechanisms that would reduce reliability. The simplicity of the adjustment feature ensures it does not compromise the overall reliability of the locking system.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP2597233B1Self-locking latch-bolt lock
Publication Date: 2018.02.21 ASTRA GESELLSCHAFT FUR ASSET MANAGEMENT MBH & CO KG
  • EP2597233B1 patent drawingFigure 1a~1c
  • EP2597233B1 patent drawingFigure 2a~2b
  • EP2597233B1 patent drawingFigure 3

AI summary

The automatic locking latch lock comprises a trap arrangement (14) which brought in a lock case (10) under compression spring force between a retracted position, a middle case position and an extended locking position. A backset is modified between a pivot axis of a knob or a door handle and a face plate (12) of the lock case.