Door Handle Retainer System with Setscrew Alignment

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Solution Overview

Problem

Existing methods for securing door handles to lock mechanisms, such as lever catches and setscrews, face issues like play between components, assembly difficulties, and security concerns, including the risk of unauthorized removal.

Innovation Solution

A door handle assembly featuring a sleeve, spindle, and handle housing with a setscrew that secures the handle by threading outwardly into the handle housing, and a tool-accessible mechanism that aligns only when the lock is unlocked, preventing unauthorized removal and minimizing play.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a setscrew is mounted through the lever handle to secure the door handle, then the handle can be secured to the lock mechanism, but the setscrew becomes accessible on the exterior and can be completely removed by unauthorized persons, allowing them to remove the handle and disable the lock mechanism

Engineering Contradiction:

ImprovesecurityVSAvoidunauthorized removal

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The setscrew is extracted from the exterior accessible position and relocated to the interior of the lever handle, where it can only be accessed through the interior opening. This removes the security vulnerability of exterior accessibility while maintaining the securing function.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The interior opening in the lever handle serves as an intermediary access path for the setscrew. Instead of direct exterior access, the setscrew is accessed through this intermediate interior opening, which is not accessible when the door is locked, thereby providing security.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If a setscrew is mounted through the lever handle, then the handle can be secured, but the setscrew can be fully backed out during installation and become lost

Engineering Contradiction:

ImproveassemblyVSAvoidretention

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The setscrew is pre-positioned within the lever handle interior before the lever handle is assembled to the door handle. This preliminary positioning ensures the setscrew cannot be lost during installation, as it is already contained within the lever handle structure.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The assembly process is segmented into distinct steps: first positioning the setscrew within the lever handle, then assembling the lever handle to the door handle. This segmentation allows the setscrew to be securely retained within the lever handle during assembly, preventing loss.

Inventive Principle:

Principle #1Segmentation

3Ease of operation

If a lever catch is used to mount the door handle, then assembly is simple, but there is play between the door handle and lock mechanism

Engineering Contradiction:

ImproveassemblyVSAvoidplay between components

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The traditional lever catch mechanical system is replaced with a setscrew fastening system. The setscrew threads into the lever handle and contacts the door handle interior surface, providing a more precise and stable mechanical connection that eliminates play while maintaining assembly simplicity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 provides a secure, play-free attachment of door handles to lock mechanisms, adaptable for both left and right-handed doors, enhancing security and assembly ease while preventing unauthorized access.

Implementation Method 1

A setscrew within the sleeve is then rotated to secure the handle and eliminate 'play' between the sleeve and the handle

Methodology Applied

Scientific EffectThreading: Screw

Implementation Method 2

The spindle opening is selectively alignable with the opening in the handle housing to allow the tool to extend through the spindle and to the fastener. Alignment of the opening in the spindle and the handle housing is only possible when in an unlocked condition

Methodology Applied

Scientific EffectMechanical alignment constraint: Geometry

Data Source

PatentUS8201307B2Door handle retainer system

Publication Date: 2012.06.19 ASSA ABLOY AMERICAS RESIDENTIAL INC

AI summary

A door handle assembly providing an entry function includes a sleeve, a spindle and a handle that fits over the sleeve. Gap and play between the handle and the sleeve is eliminated by tightening of a threaded fastener against an inner surface of the handle. A tool is selectively received through an opening in the spindle for tightening the threaded fastener. The opening in the spindle is alignable with an aperture in the handle when in an unlocked condition. The tool is then permitted to extend through the aperture and the opening in the spindle to engage the threaded fastener. A second end of the threaded fastener abuts the inner surface of the handle, securing the handle to the sleeve. Another door handle assembly according to this invention provides a privacy function and includes a threaded fastener that contacts an inner surface of a door handle assembly.