Spring Preload Adjustment for Long-Life Cable Clamping

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Solution Overview

Problem

Existing cable clamps with elastomer clamping blocks face issues with maintaining sufficient preload force over time due to elastomer degradation, leading to potential loosening and unreliable clamping connections.

Innovation Solution

A device with slidably guided receiving bodies and markings for adjusting the preload force, allowing for optical detection of the required preload through aligned markings, ensuring a stable and defined clamping force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If elastomer clamping blocks are used in cable clamps, then the clamping force is sufficient initially, but the preload force decreases over time due to elastomer degradation

Engineering Contradiction:
Improvepreload forceVSAvoidservice life
Core Design Contradiction:
ForceVSDuration of action of stationary object

Solution Approach 1:

The patent introduces an adjustable preload mechanism that allows dynamic adjustment of the spring force. The second spring element can be repositioned along the threaded spindle to different axial positions, enabling the preload force to be adapted and maintained throughout the service life of the clamp, compensating for elastomer degradation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the preload parameter by allowing adjustment of the spring's effective length through the position of the second spring element on the threaded spindle. By modifying this geometric parameter, the preload force can be optimized at different stages of the clamp's service life to compensate for material degradation.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a second spring element is added to maintain preload, then the clamping connection remains reliable, but the device complexity increases

Engineering Contradiction:
Improveclamping connection reliabilityVSAvoidspring adjustment mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The second spring element serves multiple functions: it maintains preload force, provides adjustment capability, and works in conjunction with the threaded spindle and lock nut as an integrated adjustment mechanism. This multi-functionality justifies the additional component by consolidating several functions into a coordinated system rather than separate mechanisms.

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

Solution Approach 2:

The adjustment mechanism is designed to be self-contained, where the second spring element, threaded spindle, and lock nut work together as an automatic adjustment system. The mechanism allows users to adjust and lock the preload force without requiring external tools or complex procedures, making the system self-sufficient.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If markings are added for preload indication, then the adjustment precision is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvepreload adjustment precisionVSAvoidmarking implementation complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent uses visual markings (color-coded or patterned indicators) on the threaded spindle or clamp body to indicate the correct position of the second spring element for achieving the desired preload force. These markings provide simple visual feedback during assembly and adjustment, enabling precise preload setting without requiring complex measurement instruments or procedures.

Inventive Principle:
Principle #32Color 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

Ensures consistent and reliable clamping by providing a simple and robust mechanism for adjusting and maintaining the preload force, preventing loosening and ensuring long-term secure cable fixation.

Implementation Method 1

a spring (2) arranged between them, by means of which a pre-tensioning force can be exerted

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the threaded spindle (44) of the clamping hook (45), into which the preloading device (17) can be screwed

Methodology Applied
Scientific EffectScrew mechanism: Screw

Data Source

PatentEP4502400B1Device for adjusting the pre-tensioning force of a spring
Publication Date: 2025.12.24 WALTER STAUFFENBERG GMBH & CO KG
  • EP4502400B1 patent drawingFigure 1~2b
  • EP4502400B1 patent drawingFigure 3
  • EP4502400B1 patent drawingFigure 4a~4b

AI summary

The invention relates to a device for adjusting the preload force of a spring, comprising two receiving bodies (1) which are slidably guided relative to each other by the other receiving body (1) and between which the spring (2) is held, wherein the receiving bodies (1) and the spring (2) have an aligned opening (15) for the passage of a threaded spindle (44) and wherein means for indicating the distance between the two receiving bodies (1) are arranged. The invention further relates to a clamp (3) with such a device.