Jaw-Coupled Spring Tensioning Mechanism to Prevent Overrun Stress

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Solution Overview

Problem

Existing tensioning mechanisms for spring storage drives in circuit breakers suffer from stress and strain on components due to the transmission of forces during the tensioning and overrun of the accumulator spring, leading to potential wear and damage.

Innovation Solution

A tensioning mechanism featuring a jaw coupling that decouples the intermediate shaft from the freewheel and intermediate gear when the accumulator spring is tensioned, using a displaceable clutch shoe and a freewheel to prevent force transmission, combined with a locking mechanism to maintain tension and a return spring for re-tensioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the intermediate shaft is directly coupled to the freewheel and intermediate gear for tensioning the storage spring, then the tensioning motor can effectively tension the storage spring, but forces during overrun are transmitted to the intermediate shaft and locking mechanism components causing stress and strain

Engineering Contradiction:
Improvetensioning capabilityVSAvoidcomponent stress
Core Design Contradiction:
PowerVSStrength

Solution Approach 1:

The jaw coupling acts as an intermediary element between the intermediate shaft and the freewheel/intermediate gear. It selectively transmits torque during tensioning while blocking force transmission during overrun, protecting the intermediate shaft and locking mechanism from excessive stresses

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The coupling transitions from a static direct connection to a dynamic selective connection. The jaw coupling engages during tensioning to transmit power, and disengages during overrun to isolate the intermediate shaft from harmful forces, adapting the connection state based on operational phase

Inventive Principle:
Principle #15Dynamics

2Strength

If the jaw coupling decouples the intermediate shaft from the freewheel during tensioning, then stress on components is reduced, but the complexity of the coupling mechanism increases

Engineering Contradiction:
Improvecomponent stress reductionVSAvoidcoupling mechanism complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The coupling mechanism is segmented into distinct functional elements: the jaw coupling with movable jaws, the intermediate shaft, the freewheel, and the locking mechanism. This segmentation allows each component to perform its specific function independently, simplifying the overall design despite the added decoupling capability

Inventive Principle:
Principle #1Segmentation

3Reliability

If the locking mechanism continuously locks the tensioning wheel, then the storage spring remains tensioned, but the tensioning motor cannot overrun to reset the mechanism

Engineering Contradiction:
Improvespring tension maintenanceVSAvoidmechanism reset capability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking mechanism transitions from a static continuous lock to a dynamic selective lock. The jaw coupling enables the locking mechanism to maintain engagement during tensioning and storage, while allowing disengagement during overrun, adapting the lock state based on operational requirements

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system operates in periodic cycles: tensioning phase where the lock is engaged, storage phase where the lock maintains tension, and reset phase where the lock is disengaged to allow overrun. This periodic engagement and disengagement enables both reliable tension maintenance and mechanism reset capability

Inventive Principle:
Principle #19Periodic 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

Reduces stress and strain on components by preventing force transmission during accumulator spring tensioning, thereby minimizing wear and damage, ensuring reliable and efficient operation of the spring storage drive.

Implementation Method 1

an intermediate wheel (4) driven by a tensioning motor (100), a freewheel (3) coupled to the intermediate wheel (4)

Methodology Applied
Scientific EffectFreewheel mechanism: Ratchet

Implementation Method 2

a jaw coupling (20) that couples the freewheel (3) to the intermediate shaft (2) for tensioning the storage spring and decouples it from the intermediate shaft (2) in the tensioned state of the storage spring

Methodology Applied
Scientific EffectJaw coupling: Mechanical Fastener

Implementation Method 3

a return spring (14) coupled to the first clutch shoe (12), which applies a spring force on the first clutch shoe (12) in the direction of the first end position

Methodology Applied
Scientific EffectElastic spring force: Spring

Implementation Method 4

a locking mechanism for releasably locking the tensioning wheel (9) in a tensioned state of the storage spring

Methodology Applied
Scientific EffectMechanical locking: Mechanical Fastener

Data Source

PatentEP3659161B1Tensioning mechanism for clamping a pre-loaded spring of a spring-loaded accumulator drive
Publication Date: 2026.03.18 SIEMENS ENERGY GLOBAL GMBH & CO KG
  • EP3659161B1 patent drawingFigure 1
  • EP3659161B1 patent drawingFigure 2

AI summary

The invention relates to a tensioning mechanism (1) for tensioning a pre-loaded spring of a spring-loaded accumulator drive. Said tensioning mechanism (1) comprises a tensioning wheel (9) coupled to the pre-loaded spring, an intermediate shaft (2) coupled to the tensioning wheel (9), an idler gear (4) that can be driven by a clamping motor, a freewheel (3) coupled to the idler gear (4), a locking mechanism (28) for detachably locking the tensioning wheel (9) in a tensioned state of the pre-loaded spring, and a dog clutch (20) that couples the freewheel (3) to the intermediate shaft (2) in order to tension the pre-loaded spring and uncouples same from the intermediate shaft (2) in the tensioned state of the pre-loaded spring.