Insect Screen Door Hinge Bushing for Easier Assembly

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Solution Overview

Problem

The installation of a sliding washer between the upper and lower parts of hinge fittings in insect screen doors is laborious, particularly when done simultaneously on multiple fittings.

Innovation Solution

A bearing bushing is designed to be easily inserted into receptacles, fixed by gluing or pressing, and accommodates a pin, providing a sliding bearing that prevents abrasive engagement and noise generation by guiding the pin's movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sliding washer is installed between the upper and lower parts of hinge fittings, then the sash can swing open and closed smoothly with prevention of abrasive movement, but the installation becomes laborious, particularly when done simultaneously on multiple fittings

Engineering Contradiction:
Improvesmooth swinging movementVSAvoidinstallation labor
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The bearing bush combines multiple functions into a single component: it provides the sliding bearing surface for smooth movement, prevents abrasive contact between metal parts, and serves as a guide for the pin. This eliminates the need for separate sliding washers and reduces assembly steps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bearing bush serves multiple purposes simultaneously: it acts as a sliding element for smooth movement, a protective element to prevent abrasion, and a positioning element to guide the pin. This multi-functionality reduces the number of separate components needed and simplifies installation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Object-affected harmful factors

If a sliding washer is positioned between upper and lower hinge parts, then abrasive movement is prevented, but the assembly process becomes more complex and time-consuming

Engineering Contradiction:
Improveabrasive movement preventionVSAvoidassembly process
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The bearing bush merges the protective function against abrasion with the sliding function into a single integrated component, eliminating the need for separate sliding washers and reducing assembly complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bearing bush acts as an intermediary element that prevents direct metal-to-metal contact, thereby preventing abrasive movement, while simultaneously providing a guided path for the pin through its bore.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If multiple hinge fittings are assembled simultaneously, then the door can be installed efficiently, but the installation of sliding washers becomes particularly laborious

Engineering Contradiction:
Improveinstallation efficiencyVSAvoidtime for sliding washer installation
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

By combining the sliding bearing function with the bearing bush, the number of separate installation steps is reduced, allowing multiple hinge fittings to be assembled more efficiently without the time-consuming task of installing separate sliding washers.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bearing bush can be pre-installed into the hinge parts before final assembly, or even pre-positioned during manufacturing, which would significantly reduce the time required during on-site installation of multiple hinge fittings.

Inventive Principle:
Principle #10Preliminary action

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

Facilitates easy assembly of hinge fittings with reduced labor and prevents damage and noise by ensuring smooth sliding movement between hinge parts.

Implementation Method 1

a sliding element in the form of a sliding disc is usually placed between the upper and lower hinge parts. This creates a sliding bearing that allows the sash to swing open and closed smoothly, while also preventing the usually metal upper hinge parts from abrasive movement on the equally metal lower hinge parts

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3708749B1Insect protection door
Publication Date: 2025.09.03 LAMMERMANN GERD
  • EP3708749B1 patent drawingFigure 1
  • EP3708749B1 patent drawingFigure 2
  • EP3708749B1 patent drawingFigure 3~4

AI summary

Insect screen door comprising a rectangular sash frame (4) made of several frame profiles (9, 10, 11, 12), which in the installation position is pivotably mounted on a mounting or cover frame (2) via at least two hinge fittings (3a, 3b, 3c), wherein each hinge fitting (3a, 3b, 3c) comprises a hinge top part (18, 33) and a hinge bottom part (19, 34) as well as a pin (20) forming a pivot axis and inserted into mutually aligned receptacles on the hinge top and bottom parts (18, 33, 19, 34), and a sliding element by means of which the hinge top part (18, 19) is slidably mounted on the hinge bottom part (19, 34), wherein the sliding element is a bushing (22) receiving the pin (20) in a bore (23), which is inserted into one of the receptacles and has an end bearing collar (24), which is located between the upper and lower hinge parts (18, 33, 19, 34).