Monolithic Piston Body for Door Closing Device

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Solution Overview

Problem

The high manufacturing effort and costs associated with locking devices for doors and windows due to the regular machining of inserts and subsequent plastic coating.

Innovation Solution

A locking device with a monolithic piston body made from plastic or liquid state materials, simplifying the structure and reducing manufacturing steps, where the damping piston is injection molded and the spring piston is die-cast, allowing for cost-effective production with sufficient stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If inserts are machined and coated with plastic, then sufficiently high forces can be transmitted while retaining advantageous friction properties, but the manufacturing effort and costs increase

Engineering Contradiction:
Improveforce transmission capabilityVSAvoidmanufacturing effort
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The invention merges the insert and piston body into a single monolithic component made of plastic or liquid state material. This eliminates the need for separate insert machining and plastic coating operations, directly resolving the contradiction by maintaining force transmission capability through the unified structure while dramatically reducing manufacturing complexity and costs.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention uses plastic or liquid state materials to create a monolithic piston body that replaces the traditional composite structure of metal insert plus plastic coating. This single material approach achieves the necessary mechanical properties and friction characteristics without requiring multiple materials and complex assembly processes.

Inventive Principle:
Principle #40Composite materials

2Reliability

If inserts are machined and coated with plastic, then the locking device can function properly, but the manufacturing costs increase

Engineering Contradiction:
Improvefunctional performanceVSAvoidmanufacturing costs
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention combines the insert and piston body into one monolithic component, eliminating multiple manufacturing steps (machining, coating, assembly) while maintaining all necessary functional properties. This directly reduces manufacturing costs while preserving the reliability required for proper locking device operation.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If the piston body is made monolithic from plastic or liquid state material, then the structure is simplified and manufacturing costs are reduced, but the force transmission capability must be maintained

Engineering Contradiction:
Improvestructural complexityVSAvoidforce transmission capability
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The invention changes the material parameters by using plastic or liquid state materials with appropriate mechanical properties to create a monolithic piston body. This allows the structure to be simplified without compromising force transmission capability, as the material properties are selected to meet the strength requirements while enabling simpler manufacturing.

Inventive Principle:
Principle #35Parameter changes

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

This approach significantly reduces manufacturing complexity and costs while maintaining stability and functionality, enabling a cost-effective design for door and window closing devices.

Implementation Method 1

a spring piston (16) acted upon by a spring (14) for applying a closing force to a closer shaft (18)

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

a damping piston (22) for damping the movement of the closer shaft (18)

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP3665354B1Closing device for closing a door or window leaf
Publication Date: 2023.11.29 GRETSCH UNITAS GMBH BAUBESCHLAGFABRIK
  • EP3665354B1 patent drawingFigure 1
  • EP3665354B1 patent drawingFigure 2
  • EP3665354B1 patent drawingFigure 3

AI summary

The invention relates to a closing device (10) for closing a door or window leaf, comprising a spring piston (16) which is 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). In order to allow a closing device to be provided in an inexpensive manner using simple structural means, the closing device is designed and developed such that the damping piston (22) or the spring piston (16) has a piston body (32, 62) which is produced monolithically and is primary-shaped from the plastic or liquid state.