Safety Door Handle Bolt Stopper for Automatic Locking

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Solution Overview

Problem

Current door handle systems require manual operation and adjustment for bolt extension/retraction, lack durability, and are not suitable for both left and right hinged installations, posing risks of damage and user inconvenience.

Innovation Solution

A door handle system with a bolt unit featuring a bolt stopper that automatically switches between blocking and release positions based on door closure, using an activation means to ensure the bolt is protected and aligned with the lock unit, allowing for easy operation and enhanced durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the bolt is allowed to extend automatically when the door closes, then the locking function is improved, but the bolt may collide with the doorframe causing damage

Engineering Contradiction:
Improvelocking functionVSAvoidbolt damage from collision
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The bolt stopper is pre-positioned to block the bolt's path before the door reaches the closed position. As the door approaches closure, the stopper prevents the bolt from extending too far and colliding with the doorframe. The stopper is designed to be disengaged at the precise moment when the bolt should lock, allowing automatic extension without damage.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If manual operation is required to extend and retract the bolt, then the bolt can be controlled precisely, but user interaction complexity increases

Engineering Contradiction:
Improvebolt controlVSAvoiduser interaction steps
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The door handle system is designed to automatically control the bolt's extension and retraction based on door position. The bolt stopper mechanism self-activates as the door moves, blocking or releasing the bolt without requiring user intervention. This eliminates the need for manual operation while maintaining precise control through the automatic mechanical linkage between door position and bolt state.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If the door handle system is designed for one-sided operation, then the structure is simplified, but it cannot be used for both left and right hinged doors

Engineering Contradiction:
Improvedoor hingel installationVSAvoidhandle structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The door handle system employs a symmetric design where the bolt stopper and activation means can be positioned on either the left or right side of the door. The mechanical components are arranged to function identically regardless of which side the door hinges on, allowing a single handle design to serve both left-handed and right-handed door installations without requiring mirror-image variants.

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

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 system ensures the bolt is protected from damage during door closure, reduces user interaction, and facilitates installation on both left and right hinged doors, enhancing durability and convenience.

Implementation Method 1

the bolt is pushed forward by springs into the locked position as soon as the door reaches the closed position

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

a biasing spring, ensuring the bolt remains retracted while the door is open

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP4484686B1A door handle system for a safety door, especially for a sliding door or swing door
Publication Date: 2025.07.30 SICK AG
  • EP4484686B1 patent drawingFigure 1
  • EP4484686B1 patent drawingFigure 2A~2B
  • EP4484686B1 patent drawingFigure 3

AI summary

A door handle system (1) comprises a bolt unit (5). The bolt unit (5) comprises a housing (7) with a bolt opening (8), a handle (9) and a bolt module (10) with a bolt (11). The bolt (11) is moveable respective to the housing (7). The bolt (11) can be moved out of the bolt opening (8) of the housing (7) for engaging with a corresponding lock opening (12). The bolt unit (5) comprises a restraining device (13) with a bolt stopper (14). The bolt stopper (14) is configured to be switched between a blocking position in which it engages with the bolt (11) and a release position in which it releases the bolt (11) thereby allowing the bolt (11) to move out of the bolt opening (8). An activation means (15) is to switch the bolt (11) from the blocking position into the release position.