Locking Rod Fitting Spring Preload for Low Friction Operation

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Solution Overview

Problem

Existing connecting rod fittings face challenges in compensating for large air gap tolerances with high frictional forces, leading to increased operating forces for users, and struggle to absorb radial forces from seal contact pressure or wind pressure, reducing stability.

Innovation Solution

A connecting rod fitting with a spring element arranged on the forend, which applies a force to the locking pin to prestress it outward, allowing for adjustment of spring force independently of the drive rod's stability, facilitating low frictional forces and reduced operating forces by enabling the locking pin to be displaced along its longitudinal direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the rod dimensions are predetermined by the forces to be transmitted, then high force is required to pull out the locking bolt, but this results in high operating forces for users at the handle

Engineering Contradiction:
Improveforce to pull out locking boltVSAvoidoperating forces at handle
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

A spring element is introduced that preliminarily acts on the locking bolt to reduce the frictional forces between the locking bolt and the strike plate during the locking operation. The spring element applies a force component that opposes the frictional resistance, thereby reducing the operating force required at the handle while maintaining the necessary locking force

Inventive Principle:
Principle #9Preliminary anti-action

2Adaptability or versatility

If a guide element is used to couple the locking bolt to the drive rod, then the locking bolt can pivot away from the drive rod, but radial forces from seal pressure or wind pressure cannot be adequately absorbed

Engineering Contradiction:
Improvepivoting movement of locking boltVSAvoidradial forces absorption
Core Design Contradiction:
Adaptability or versatilityVSForce

Solution Approach 1:

The coupling between the locking bolt and drive rod is segmented into two functional components: a guide element that enables pivoting movement for adaptability, and a separate support structure (the spring element and its mounting on the drive rod) that provides radial support to absorb seal pressure and wind pressure. This segmentation allows each component to specialize in its primary function without compromise

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If the locking bolt requires sufficient play in the passage to allow pivoting movement, then the locking bolt can accommodate radial forces, but this reduces stability

Engineering Contradiction:
Improvepivoting movement capabilityVSAvoidstability of locking bolt position
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The system transitions from a static rigid connection to a dynamic coupled system where the locking bolt can pivot within controlled limits through the guide element, while the spring element dynamically adjusts to maintain optimal contact and stability. The spring element's elastic properties allow it to accommodate small movements while maintaining stable engagement, providing both adaptability and stability simultaneously

Inventive Principle:
Principle #15Dynamics

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 effectively compensates for large air gap tolerances with low frictional forces, reducing operating forces on the handle and enhancing stability by allowing the locking pin to be displaced with reduced displacement forces, thus improving user experience and system stability.

Implementation Method 1

a spring element is arranged on the side of the faceplate facing away from the drive rod (faceplate exterior), which is supported on the faceplate and exerts a force on the locking bolt that forces or attempts to bring the locking bolt into a position extended relative to the faceplate

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

the rod, which is slightly spaced from the faceplate, deforms elastically. This allows for gap compensation

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3783176B1Drive rod fitting, door or window closure and door or window assembly
Publication Date: 2021.10.13 GRETSCH UNITAS GMBH BAUBESCHLAGFABRIK
  • EP3783176B1 patent drawingFigure 1
  • EP3783176B1 patent drawingFigure 2~3
  • EP3783176B1 patent drawingFigure 4~6

AI summary

A locking rod fitting (10) for a door or window sash, comprising a faceplate (12), a locking rod (14) arranged on the faceplate (12) and longitudinally displaceable relative to the faceplate (12), and a locking bolt (16) attached to the locking rod (14) and projecting through an elongated hole (18) formed in the faceplate (12), is designed and further developed in such a way as to provide a stable locking rod fitting with simple design means in which only low frictional forces occur even when compensating for large rebate tolerances, such that a spring element (30) is arranged on the side of the faceplate (12) facing away from the locking rod (14), which is supported on the faceplate (12) and exerts a force on the locking bolt (16) to bring the locking bolt (16) into a position extended relative to the faceplate (12). A door or window lock and a door or window assembly with such a locking rod fitting are specified.