Nested Tension Spring End Closure for Compact High-Force Assembly

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Solution Overview

Problem

Existing spring assemblies face challenges in achieving higher tensile forces within a limited space while maintaining cost-effectiveness and efficient production.

Innovation Solution

The solution involves arranging three tension springs with different outer diameters one inside the other, with modified end areas where the outer spring is spread, the middle spring is also spread, and the inner spring is constricted, allowing for a compact and powerful connection using external end elements and connecting elements with hook-shaped locks that engage between the coils.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If multiple tension springs are arranged concentrically to increase tensile force in limited space, then the tensile force capability is improved, but the complexity of connecting the springs increases

Engineering Contradiction:
Improvetensile forceVSAvoidconnection complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent applies nesting by arranging three tension springs (first, second, and third tension springs) concentrically, with each spring placed inside the previous one. This nested configuration allows multiple springs to occupy the same spatial envelope, significantly increasing the total tensile force capability while maintaining a compact overall size. The connecting elements are designed to engage with all nested springs simultaneously through a single connection point, further simplifying the assembly process despite the complex internal structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of manufacture

If conventional connection methods are used for nested springs, then the assembly is simple, but additional fastening elements increase device complexity and manufacturing costs

Engineering Contradiction:
Improvemanufacturing costVSAvoidnumber of fastening elements
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the functions of multiple connection points into a single integrated connecting element. Instead of requiring separate fasteners for each spring, the connecting element is designed with a unified structure that engages with all three nested springs simultaneously through its geometric configuration. This merging approach eliminates the need for additional fastening elements, reducing both device complexity and manufacturing costs while maintaining secure connection of all springs.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The connecting elements utilize the existing geometric features of the tension springs (such as the wire diameter and coil structure) to create self-retaining connections. The connecting elements are designed to engage with the springs in a way that allows the spring's own structure to provide the connection interface, eliminating the need for separate fastening components. This self-service approach reduces the bill of materials and simplifies assembly.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4130509A1End closure for a spring package
Publication Date: 2023.02.08 ALCOMEX BEHEER BV
  • EP4130509A1 patent drawingFigure 1
  • EP4130509A1 patent drawingFigure 2
  • EP4130509A1 patent drawingFigure 2a

AI summary

The invention relates to an end termination (35) for a spring assembly consisting of several tension springs (1, 2, 3), in which the individual tension springs (1, 2, 3) to be connected each have a different outer diameter and are arranged inside one another as a spring assembly and are connected to each other by retaining elements, wherein the outer tension spring (1) and the middle tension spring (3) arranged therein each have a spreading (19, 21) in their end regions between adjacent coils, and the inner tension spring (2) arranged in the tension spring (3) has a partial constriction (22) of its outer diameter in its end region, in their end regions the tension springs (1, 2, 3) are each connected to each other by termination elements (4, 5, 36, 43) attachable from outside the spring assembly and simultaneously by connecting elements (6, 39), the termination elements (4, 5, 36, 43) are designed as identical parts.which have an upper bracket (10) for engaging in the constriction (22) of the inner tension spring (2) and a lower bracket (14) for engaging in the expansion (21) of the middle tension spring (3), the outer tension spring (1) is held by the connecting elements (6, 39) engaging in the expansion (21), so that there is an overall force-fit and form-fit between the tension springs (1, 2, 3), the end elements (4, 5, 36, 43) and the connecting elements (6, 39).