Door Handle Assembly Using Threaded Square Spindle and Bearing Bushings

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Solution Overview

Problem

Existing door handle systems require precise positioning and drilling of boreholes, which can lead to assembly difficulties and potential damage to the door due to misalignment and non-concentric installation of components.

Innovation Solution

A handle system utilizing bearing bushes with a threaded square pin and a threaded nut for precise positioning, where the bushes are pressed into the door bore, eliminating the need for drilling and ensuring concentric alignment through radially protruding collars and webs, facilitating easier assembly and preventing damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If drill holes are pre-drilled in the door for mounting escutcheon/base combinations, then the handles can be securely mounted, but the positioning precision requirements increase and assembly complexity increases

Engineering Contradiction:
Improvemounting securityVSAvoiddrill hole positioning precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The bearing bushings are pre-assembled with the escutcheon/base combinations and the square spindle, creating a pre-assembled unit that can be directly pressed into the door without requiring pre-drilled holes. This preliminary assembly eliminates the need for precise drill hole positioning while maintaining secure mounting.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The pressing-in mechanism extracts the requirement for pre-drilled holes from the mounting process. By using a pressing-in mechanism with the bearing bushings, the system eliminates the need for separate drilling operations and the associated precision requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If drill holes are pre-drilled in the door, then handles can be mounted, but the assembly process becomes more complex and time-consuming

Engineering Contradiction:
Improvemounting securityVSAvoidassembly process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple components (escutcheon/base combinations, bearing bushings, square spindle, and mounting hardware) are merged into a single pre-assembled unit. This consolidation reduces the number of separate steps required during installation, eliminating the need for separate drilling, fitting, and securing operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The escutcheon/base combinations, bearing bushings, and square spindle are pre-assembled before installation. This preliminary assembly simplifies the on-site installation process to a single pressing-in operation, significantly reducing assembly complexity and installation time.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If bearing bushings are hammered into the door bore, then they can be installed without drilling, but the door may be damaged and concentric alignment becomes difficult

Engineering Contradiction:
Improveinstallation simplicityVSAvoiddoor damage risk
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The bearing bushings are designed with a pressing-in mechanism that distributes the installation force evenly, cushioning against the door material to prevent localized damage. The gradual pressing-in process replaces the sudden impact force of hammering, eliminating the risk of door damage while maintaining installation simplicity.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Ease of manufacture

If bearing bushings are hammered into the door bore, then they can be installed without drilling, but concentric alignment with the lock follower becomes difficult

Engineering Contradiction:
Improveinstallation simplicityVSAvoidconcentric alignment precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The square spindle acts as an intermediary element that connects the bearing bushings to the lock follower. During the pressing-in process, the square spindle is inserted through the lock follower first, serving as a guide that ensures the bearing bushings are pressed in concentrically with the lock follower, eliminating alignment difficulties.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3205794B1Handle system and method of assembly
Publication Date: 2019.06.26 HEWI HEINRICH WILKE GMBH
  • EP3205794B1 patent drawingFigure 1~2
  • EP3205794B1 patent drawingFigure 3~4
  • EP3205794B1 patent drawingFigure 5~6

AI summary

The present invention relates to a handle system for mounting on a door having a door bore. The handle system comprises a first handle, a second handle, a square spindle which serves to connect the handles and has a first end section which can be attached to or is attached to the first handle in a pre-assembled state, as well as a first bearing bushing for supporting the first handle and a second bearing bushing for supporting the second handle, wherein the bearing bushings each have a passage for receiving the square spindle. The square spindle is provided with a thread in a second end section facing away from the first end section, onto which a threaded nut can be screwed in order to press the at least one bearing bushing into the door bore. The invention further relates to a method for mounting the handle system.