Curved Latch Bolt Guide Surface for Reduced Opening Force

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Solution Overview

Problem

Existing door opener units often require high opening forces and can be noisy due to constant friction conditions and non-adaptive latch pressing speeds, leading to a difficult and unpleasant opening experience.

Innovation Solution

A door opener unit with a curved lock latch guide surface that adapts friction conditions and latch pressing speed by featuring multiple sliding sections with varying curvatures and slopes, ensuring smooth transitions and reduced noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a flat lock latch guide surface is used, then the structure is simple, but the door requires high opening forces and generates noise due to constant friction conditions

Engineering Contradiction:
Improveguide surface structureVSAvoiddoor opening ease
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The lock latch guide surface is designed with a curved profile instead of a flat surface. The curvature varies along the sliding path, creating zones with different friction characteristics. This allows the latch to slide smoothly during door opening while maintaining simplicity in the overall guide surface structure.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Ease of operation

If a curved lock latch guide surface is used, then the friction conditions are adapted and opening is easier, but the device complexity increases

Engineering Contradiction:
Improvedoor opening easeVSAvoidguide surface structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The curved guide surface is divided into multiple sliding zones with different curvature radii. The first zone has a larger radius for initial engagement, while subsequent zones have progressively smaller radii to increase friction and pressing force. This segmentation allows complex friction adaptation without requiring an entirely complex guide surface structure.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If constant latch pressing speed is used, then the mechanism is simple, but the opening process is noisy and requires high forces

Engineering Contradiction:
Improvelatch pressing mechanismVSAvoidnoise and opening force
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The latch pressing speed is made variable through the curved guide surface design. As the door opens, the changing curvature dynamically adjusts the pressing force - starting with gentle engagement and progressively increasing the pressing speed and force. This dynamic adaptation reduces noise and required opening forces without complex additional mechanisms.

Inventive Principle:
Principle #15Dynamics

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

The adapted friction conditions and variable latch pressing speed enhance the ease and smoothness of door opening, reducing noise and the subjective effort required, providing a harmonious opening process.

Implementation Method 1

friction phenomena occurring here

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2159355B1Door opener unit with curved latch bolt guide surface
Publication Date: 2014.02.26 ASSA ABLOY SICHERHEITSTECHNIK GMBH
  • EP2159355B1 patent drawingFigure 1
  • EP2159355B1 patent drawingFigure 2~3

AI summary

The opener unit (101) has a retaining area (105) engaged with a lock latch (S) of a door lock. The retaining area is partially limited by a lock latch guiding surface (106) in a door opening direction (O). The lock latch slides on the guiding surface during opening of a door until the lock latch is withdrawn from the retaining area. The guiding surface is formed to be curved along individual sliding sections for the lock latch. A curving axis extends perpendicular to the opening direction and to an engaging direction (E) of the latch.