Bellows Fastening Means With Inner Undercut Region

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Solution Overview

Problem

Existing fastening means for bellows, such as endless clamping rings, often fail to securely close the free ends of band-shaped sections, leading to potential opening during transport or use, especially under dynamic loads, and require expensive welding or crimping processes.

Innovation Solution

A fastening means with a male and female end section, featuring an inner undercut area in the male end section and a mushroom-shaped projection in the female end section, which interlock to provide enhanced closure and resistance to opening, incorporating additional outer undercut areas for improved stability and material overlaps to prevent gap formation under stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If welding or crimping processes are used to close the free ends of band-shaped sections, then the closure strength is improved, but the manufacturing complexity and cost increase

Engineering Contradiction:
Improveclosure strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The fastening means is divided into male and female end sections with complementary geometries. The male end section includes a base, foot section, and head part with undercut areas, while the female end section has corresponding recesses and protrusions. This segmentation allows the components to interlock mechanically without requiring welding or crimping, thus maintaining closure strength while reducing manufacturing complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The male and female end sections are designed to nest within each other when assembled. The foot section of the male end section engages into the recess of the female end section, and the head part with undercut areas interlocks with the complementary features. This nested configuration provides secure closure without additional joining processes

Inventive Principle:
Principle #7Nested doll (Nesting)

2Device complexity

If simple overlapping tensioning straps are used, then the manufacturing complexity is reduced, but the reliability of closure under dynamic loads deteriorates

Engineering Contradiction:
Improvemanufacturing complexityVSAvoidclosure reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The fastening means employs asymmetric geometries in the male and female end sections. The male end section features a foot section with specific profile and a head part with undercut areas, while the female end section has complementary asymmetric recesses and protrusions. This asymmetric design creates a mechanically interlocked connection that reliably resists opening under dynamic loads, unlike simple symmetric overlapping straps

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention introduces undercut areas that extend in multiple dimensions. The head part of the male end section has undercut areas that create three-dimensional interlocking features, allowing the fastening means to resist forces from multiple directions. This multi-dimensional engagement significantly improves closure reliability compared to simple two-dimensional overlapping straps

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

3Device complexity

If endless clamping rings are used without improved closure features, then the device complexity is reduced, but the stability under tensile stress deteriorates

Engineering Contradiction:
Improvedevice complexityVSAvoidclosure stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The male and female end sections are pre-configured with complementary geometries including undercut areas, recesses, and protrusions before assembly. This preliminary configuration ensures that when the fastening means is assembled, the interlocking features automatically engage to provide stable closure under tensile stress, eliminating the need for additional stabilization measures

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3140554B1Fastening means, in particular for bellows, having an inner undercut region
Publication Date: 2020.06.24 GKN DRIVELINE INT GMBH
  • EP3140554B1 patent drawingFigure 1
  • EP3140554B1 patent drawingFigure 2a
  • EP3140554B1 patent drawingFigure 2b

AI summary

The invention relates to a fastening means (10), in particular for bellows, comprising a male end segment (14) and a female end segment (16) complementary to the male end segment, and to the use of said fastening means to fasten bellows to joint housings and/or shafts. According to the invention, said fastening means has an inner undercut region (36) in order to provided an improved closing behavior of the fastening means.