Door Fitting Locking Mechanism for Narrow Tubular Frames

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Solution Overview

Problem

Existing door fittings are difficult to install and lack secure fastening mechanisms, particularly on tubular frame doors, which are narrow and do not allow for conventional mounting methods.

Innovation Solution

A door fitting with a mounting device featuring a locking device that moves between locking and release positions, secured by a pin element recess and fastening elements, ensuring the fitting can only be removed when the door is open, and incorporating an electronic module for enhanced security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional mounting methods are used on tubular frame doors, then the mounting process becomes difficult and time-consuming, but the narrow frame design limits the available space for mounting elements

Engineering Contradiction:
Improveease of installationVSAvoidavailable mounting space
Core Design Contradiction:
Ease of manufactureVSArea of stationary object

Solution Approach 1:

The mounting device is divided into separate functional components: a mounting plate for attachment to the door, a locking device with movable locking elements, and a fitting device for securing the handle. This segmentation allows each component to be optimized independently and simplifies the installation process by enabling modular assembly on the narrow tubular frame

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking device utilizes movement in a direction perpendicular to the door surface (along the mounting axis) to achieve secure fastening. The locking elements can move between engaged and disengaged positions, providing a third dimension of control beyond the limited two-dimensional mounting space on the narrow frame

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If simple fastening mechanisms are used, then the installation is easier, but the security against unauthorized removal is insufficient

Engineering Contradiction:
Improvesecurity against unauthorized removalVSAvoidcomplexity of fastening mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking device incorporates movable locking elements that can transition between locked and unlocked states. The locking elements are positioned to engage with corresponding features on the fitting device, creating a dynamic fastening system that provides high security when engaged but can be readily released when needed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking device acts as an intermediary mechanism between the mounting plate and the fitting device. It provides the necessary security function while maintaining a relatively simple overall structure, as the locking elements are integrated into the mounting assembly rather than requiring separate complex fastening systems

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the fitting device is securely fastened to prevent removal, then security is improved, but the ability to service or replace the fitting becomes difficult

Engineering Contradiction:
Improvetamper-proof attachmentVSAvoidease of servicing or replacing fitting
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The locking device uses movable locking elements that can be easily transitioned between engaged and disengaged states. This dynamic mechanism provides tamper-proof attachment when locked but allows straightforward servicing or replacement when unlocked, eliminating the trade-off between security and maintainability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking device is designed to be self-contained and self-operating. The locking and unlocking functions are integrated into the mounting mechanism itself, allowing the fitting to be secured or serviced without requiring external tools or complex procedures. The movable locking elements can be actuated directly through the existing mounting structure

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3974604B1Door fitting, especially for a tubular frame door
Publication Date: 2025.07.16 DORMAKABA SCHWEIZ AG
  • EP3974604B1 patent drawingFigure 1
  • EP3974604B1 patent drawingFigure 2
  • EP3974604B1 patent drawingFigure 3

AI summary

The invention relates to a door fitting (1) comprising a mounting device (2) designed for mounting on a door (101), and a fitting device (4) designed for attachment to the mounting device (2), with a handle area (43) for receiving a handle (8), in particular a door handle, wherein the mounting device (2) comprises a mounting plate (21) and a locking device (25) movably arranged on the mounting plate (21) in a locking position and a release position, wherein the locking device (25) is designed to engage positively in the fitting device (4) in the locking position in order to attach the fitting device (4) to the mounting device (2), and wherein the locking device (25) has a first pin element recess, in particular a lock cylinder recess (26), for inserting a pin element, in particular a lock cylinder.exhibits and the first pin element recess (26) is designed such that an inserted pin element blocks movement of the locking device (25) from the locking position to the release position.