Snap Ring Locking for Door Fittings With Easy Disassembly

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Solution Overview

Problem

Existing rest systems for door or window fittings face challenges such as increased friction due to manufacturing tolerances, difficulty in assembly and disassembly, and the sprinkler's ability to rotate freely around the axis of rotation, making it hard to disassemble the system.

Innovation Solution

A pressed grate with a sprinkling surface that limits the sprinkler's movement around the axis of rotation, combined with a thorn sleeve that has a conical import area and a puncture, allowing for easy assembly and disassembly by ensuring the sprinkler is always in a favorable position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the snap ring is allowed to rotate freely around the rotation axis, then the assembly can accommodate manufacturing tolerances, but the snap ring may move to unfavorable positions making disassembly difficult

Engineering Contradiction:
Improveaccommodation of manufacturing tolerancesVSAvoiddisassembly difficulty
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The embossing on the snap ring support surface pre-positions the snap ring at a favorable location before assembly is completed. This preliminary positioning ensures that the snap ring opening remains accessible for disassembly operations, preventing the snap ring from rotating to unfavorable positions while still allowing accommodation of manufacturing tolerances through the conical insertion surface.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The embossing creates an asymmetric feature on the otherwise symmetric snap ring support surface. This asymmetric element restricts the snap ring's rotational freedom by providing a preferred positioning feature, while the overall symmetric conical insertion surface still allows for tolerance accommodation in the radial direction.

Inventive Principle:
Principle #4Asymmetry

2Ease of operation

If the snap ring is constrained to a fixed position, then disassembly becomes easier, but the system cannot accommodate manufacturing tolerances in door processing

Engineering Contradiction:
Improvedisassembly easeVSAvoidaccommodation of manufacturing tolerances
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The positioning function is segmented into two independent components: the conical insertion surface handles tolerance accommodation through its self-aligning geometry, while the embossing handles snap ring positioning for easy disassembly. This segmentation allows each feature to optimize its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The solution moves the positioning constraint from the rotational dimension to the axial dimension. The embossing constrains the snap ring axially rather than radially, allowing the snap ring to still accommodate radial tolerances while preventing rotation to unfavorable angular positions.

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

3Productivity

If the snap ring is positioned favorably for disassembly, then assembly time is reduced, but the structure becomes more complex

Engineering Contradiction:
Improveassembly speedVSAvoidstructure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Instead of modifying the entire snap ring support surface, only a localized embossing feature is added. This local modification provides the necessary positioning function without fundamentally changing the overall structure, maintaining simplicity while enabling faster assembly and disassembly operations.

Inventive Principle:
Principle #3Local quality

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 enables easier and quicker assembly and disassembly of door or window fittings, reduces friction, and ensures the system functions properly even with larger deviations in thorn sleeve alignment.

Implementation Method 1

a snap ring which is dimensioned such that it can be pushed over the conical insertion surface of the mandrel sleeve and is thereby spread open

Methodology Applied
Scientific EffectConical expansion: Wedge

Implementation Method 2

the snap ring support surface has an outwardly directed embossing extending in the axial direction... the snap ring can only move to a limited extent around the rotation axis of the locking system

Methodology Applied
Scientific EffectGeometric constraint: Geometry

Data Source

PatentEP3770360B1Door or window fitting, snap ring, push escutcheon and locking system for door or window fittings
Publication Date: 2025.04.30 GLUTZ AG
  • EP3770360B1 patent drawingFigure 1~3
  • EP3770360B1 patent drawingFigure 4~5b
  • EP3770360B1 patent drawingFigure 6~8

AI summary

The present invention relates to a snap ring (14) for locking systems of a door or window fitting in the form of an annular disc open at one point (14a), comprising an inner contour (14d) and an outer contour (14c), wherein the snap ring (14) has a recess (14b) which represents an area of ​​reduced width of the disc, wherein the recess (14) is located on the side of the disc opposite the ring opening (14a), and wherein the snap ring (14) has pliers clearances (17d) at the ring opening (14a) for the engagement of pliers jaws of pliers, in particular gripping pliers or spreading pliers.