Mortise Lock Bolt With Sliding Tension Plate

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Solution Overview

Problem

Mortise locks with a single bolt face challenges in efficiently transitioning from a door-closed position to a locking position due to high frictional forces, making door locking uncomfortable or impossible.

Innovation Solution

A bolt design featuring a main body and a tension adjuster plate that allows relative movement, reducing friction by using pin barrings with spring and ball elements to facilitate smooth operation between the main body and the striking plate, enabling the bolt to move between door-closed, locking, and retracted positions without high friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single bolt is used to fulfill both door-closing and locking functions, then the device complexity is reduced, but the ease of operation deteriorates due to high frictional forces during position transition

Engineering Contradiction:
Improvenumber of boltsVSAvoidease of bolt operation
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The bolt is divided into two independent functional parts: a main body for locking function and a tension adjuster plate for door-closing function. This segmentation allows each part to be optimized independently - the main body can be moved without the tension adjuster plate, reducing friction during locking operation while maintaining the benefit of a single integrated bolt structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tension adjuster plate acts as an intermediary element between the door and the main body. It absorbs the frictional forces generated during door-closing operation, allowing the main body to move independently with reduced friction when transitioning to the locking position.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the bolt is pressed against the striking plate to keep the door closed, then the door sealing is improved, but the frictional forces increase making locking difficult

Engineering Contradiction:
Improvedoor sealingVSAvoidease of bolt operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The bolt is divided into two independent functional parts: a main body for locking function and a tension adjuster plate for door-closing function. This segmentation allows each part to be optimized independently - the main body can be moved without the tension adjuster plate, reducing friction during locking operation while maintaining the benefit of a single integrated bolt structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The high frictional forces that normally hinder locking operation are converted into a beneficial function by the tension adjuster plate. The plate is designed to slide along the main body, and the friction between the plate and striking plate is harnessed to maintain door-closing force and sealing, while the main body can still move independently for locking.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 reduces frictional forces during locking and unlocking, allowing for comfortable and efficient operation of the mortise lock, maintaining the door's sealed position while minimizing the impact of high frictional forces.

Implementation Method 1

Each pin barring comprises a spring element and a ball element

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

Each pin barring comprises a spring element and a ball element

Methodology Applied
Scientific EffectBall bearing: Ball Bearing

Data Source

PatentEP3578739B1Bolt for a mortise lock
Publication Date: 2020.11.18 DORMAKABA DEUT GMBH
  • EP3578739B1 patent drawingFigure 1~2
  • EP3578739B1 patent drawingFigure 1
  • EP3578739B1 patent drawingFigure 3

AI summary

The invention regards a bolt (1) of a mortise lock (2), the bolt (1) being adapted to be introduced into a striking plate (3) and comprising: a main body (4) including a connecting part (5) adapted to be coupled with a driving element (6) of the mortise lock (2), and a tension adjuster plate (7) provided on an outer surface (8) of the main body (4), wherein the tension adjuster plate (7) is linearly slidable along the outer surface (8) of the main body (4).