Lock Body Latch Bolt Buffer Structure for Noise Reduction

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Solution Overview

Problem

Existing door locks generate noise due to impact between internal components, and previous solutions like rubber rings and damping oils have limitations such as aging or increased resistance in cold environments, failing to effectively reduce noise across various occasions and environments.

Innovation Solution

A latch bolt buffer structure comprising a latch bolt assembly connected to a damper via a connecting rod, with a silencing mechanism that uses a torsion spring and damping flat shaft to slow down the latch bolt's extension and retraction, minimizing noise through rotational resistance and silencing blocks, ensuring stability and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If rubber ring is mounted on pull rod to reduce impact noise, then noise is reduced, but rubber ring ages and adheres to pull rod causing bolt to fail extending or retracting

Engineering Contradiction:
Improveimpact noiseVSAvoidbolt extension and retraction functionality
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

A silencing block made of sound-absorbent plastic is introduced as an intermediary between the latch bolt and the box bottom. This mediator absorbs impact noise while maintaining bolt functionality, avoiding the aging and adhesion problems of rubber rings directly mounted on the pull rod.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The silencing block is designed as a replaceable component that can be easily replaced when worn or degraded. This allows the noise-reducing function to be maintained without compromising the permanent bolt mechanism, addressing both noise reduction and reliability concerns.

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

2Object-generated harmful factors

If damping oil is added to eliminate collision sound, then noise is reduced, but damping oil condenses in cold environment increasing resistance and making latch bolt dull

Engineering Contradiction:
Improvecollision noiseVSAvoidperformance in cold environment
Core Design Contradiction:
Object-generated harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent replaces the fluid-based damping oil system with a solid mechanical damping structure consisting of silencing blocks and sound-absorbent plastic components. This mechanical substitution eliminates the temperature-sensitive condensation issue while maintaining noise reduction functionality across different environments.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the physical state parameter from liquid (damping oil) to solid (silencing blocks and plastic materials). This parameter change makes the noise reduction mechanism insensitive to temperature variations, ensuring consistent performance in both cold and warm environments.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If traditional latch bolt structure is used, then structure is simple, but impact between internal components generates noise

Engineering Contradiction:
Improvelatch bolt structureVSAvoidimpact noise
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The noise-generating impact function is extracted from the main latch bolt mechanism by introducing separate silencing blocks and sound-absorbent plastic components. These extracted elements specifically address noise reduction without complicating the core bolt structure, maintaining simplicity while reducing noise.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution effectively reduces noise during door operation by maintaining consistent speed and minimizing frictional sounds, providing a high-safety, stable, and silent lock body suitable for diverse environments.

Implementation Method 1

the damper generates rotational resistance to slow down the swing moment, thereby achieving the buffer for the extension (or retraction) of the latch bolt

Methodology Applied
Scientific EffectDamping: Damping

Implementation Method 2

a reversing plate and a torsion spring are fixed at corresponding positions on a bottom plate surface of the box bottom

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3492676B1Buffer structure for lock body latch bolt
Publication Date: 2023.05.03 GUANGDONG MINGMEN LOCKS IND
  • EP3492676B1 patent drawingFigure 1
  • EP3492676B1 patent drawingFigure 2
  • EP3492676B1 patent drawingFigure 3

AI summary

The present disclosure provides a latch bolt buffer structure for a lock body, including an outer lining board (1) for the lock body, a latch bolt assembly (5), a damper (7), a connecting rod (6), a latch bolt poking mechanism (4), a dead bolt mechanism (4), a box cover (8) and a box bottom assembly (2) for the lock body. The latch bolt assembly (5) includes a latch bolt (53), a friction bolt (51), a pull rod (56), a spring (54), a limiting silencing ring (55), and a slider (57). The box bottom assembly (2) includes an inner lining board (21) for the lock body, a silencing block (22) for the dead bolt, a silencing block (29) for the latch bolt, a box bottom (20), a positioning plate (27), a spring (25), a fixing nail (24) and a damper (27). One or more manufacturing parts made of a sound-absorbent plastic material, such as nylon, TPE elastic plastic, ABS or other sound-absorbent materials, is adopted to replace metal parts, or a method of separating the metal parts by sound-absorbent plastic material is adopted to reduce the noise generated by friction. At the same time, the buffer function of the damper is used to reduce the sound generated by the collision of the parts when the lock body is working.