Door and Window Closer Piston Inserts for Force Distribution

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Solution Overview

Problem

Conventional locking devices for doors and windows suffer from high manufacturing costs and complexity due to numerous components, and the use of plastic and non-ferrous metal alloys leads to material fatigue and erosion, requiring improved force distribution and material selection.

Innovation Solution

A locking device with a two-part piston design, featuring a piston body and insert, where the insert distributes forces over a large surface area, allowing the use of easier-to-process materials like zinc or plastic, and includes a cup-shaped recess for the roller to enhance durability and reduce assembly complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional locking devices use numerous machined components, then the device can achieve basic functionality, but the manufacturing effort and costs become comparatively high

Engineering Contradiction:
Improvemanufacturing effortVSAvoidnumber of components
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent combines multiple individual components into integrated units. The piston body integrates the bearing surface, sealing elements, and connection features into a single component. The housing combines the cylindrical body, end caps, and mounting features together. This merging reduces the total number of components and simplifies manufacturing while maintaining the locking device's functionality.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If the damping piston and spring piston are made from plastic or non-ferrous metal alloys, then the device can be manufactured more easily, but the bearing surfaces suffer from fatigue and erosion leading to reduced service life

Engineering Contradiction:
Improveease of processingVSAvoidservice life
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent employs composite construction where the piston body is made from easily processable materials like plastic or non-ferrous metal alloys, while the bearing surfaces are reinforced with耐磨 (wear-resistant) inserts or coatings. This composite approach allows the main body to be manufactured easily while the critical bearing surfaces maintain high durability and resistance to fatigue and erosion.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different material properties to different parts of the piston. The main piston body uses easily processable materials, while the specific bearing surfaces that contact the roller are enhanced with wear-resistant materials or coatings. This local quality enhancement ensures that only the critical areas have the necessary durability while the overall device remains easy to manufacture.

Inventive Principle:
Principle #3Local quality

3Device complexity

If foot sections are used on the spring piston to bridge the closer shaft, then the structure can be simplified, but tight tolerances are required to avoid damage to the foot sections

Engineering Contradiction:
Improvestructural simplicityVSAvoidtolerance requirements
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent introduces an intermediary element (such as a bearing insert or protective coating) between the foot sections and the closer shaft. This intermediary component absorbs the tolerance variations and prevents direct contact that could damage the foot sections, allowing for looser tolerances while maintaining structural simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 reliable and durable locking device with reduced manufacturing effort and costs, while minimizing material fatigue and erosion, ensuring stable force distribution and easy assembly.

Implementation Method 1

the roller is in contact with the closer shaft... the forces acting from the roller on the bearing surfaces of the damping piston can lead to fatigue and erosion

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a spring piston (16) loaded with a spring (14), which exerts a closing force on the closer shaft (18)

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 3

a damping piston (22), which damps the movement of the closer shaft (18)

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Data Source

PatentEP3885519B1Device for closing a door or window leaf
Publication Date: 2025.08.27 GRETSCH UNITAS GMBH BAUBESCHLAGFABRIK
  • EP3885519B1 patent drawingFigure 1
  • EP3885519B1 patent drawingFigure 2a~2c
  • EP3885519B1 patent drawingFigure 3a~3c

AI summary

A closing device (10) for closing a door or window sash, comprising a spring piston (16) acted upon by a spring (14) for applying a closing force to a closing shaft (18) and a damping piston (22) for damping the movement of the closing shaft (18), is designed and further developed in such a way as to provide a reliable and durable closing device with simple design means, such that the damping piston (22) and/or the spring piston (16) each have a piston body (32, 34), wherein a cup-shaped recess (36, 38) is formed on the end face of the piston body (32, 34), into which an insert (40) with a roller (42) for engagement with the closing shaft (18) is inserted, wherein the roller (42) is rotatably mounted on the insert (40) by means of an axle (44).