Motor Operator Decoupling Camshaft Position Sensing

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Solution Overview

Problem

Existing electrical switching apparatuses lack a decoupling mechanism to prevent damage from continued rotational force when the charging motor fails to stop, as the over-running clutch assembly does not disengage the hub assembly from the sprocket in such events.

Innovation Solution

A decoupling assembly that includes a lifter pin assembly and an elongated second end to a link member, which pivots to move a pawl between engaging and disengaging positions, allowing the hub assembly to 'float' on the sprocket and prevent rotational force transfer from the motor shaft to the cam shaft in case of motor failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the over-running clutch assembly is used to charge the closing springs, then the closing springs can be charged by motor rotation, but the hub assembly remains engaged with the sprocket causing continued rotation to transfer force to the cam shaft and potentially damage the apparatus

Engineering Contradiction:
Improvemotor operation reliabilityVSAvoidrotational force damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The decoupling assembly acts as an intermediary mechanism between the hub assembly and the cam shaft. When the motor fails to stop, the decoupling assembly engages to prevent rotational force from being transferred to the cam shaft, thereby protecting the apparatus from damage while allowing the motor to continue operating safely.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system transitions from a static engaged state to a dynamic decoupled state when motor failure is detected. The hub assembly can disengage from the sprocket under excessive rotational force, allowing the motor to continue rotating without transferring damaging forces to the cam shaft and closing springs.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the hub assembly is permanently engaged with the sprocket, then motor rotation reliably charges the closing springs, but motor failure to stop causes continued force transfer and potential apparatus damage

Engineering Contradiction:
Improvecharging efficiencyVSAvoidmotor failure damage
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The engagement between the hub assembly and sprocket is made dynamic rather than permanent. The decoupling assembly allows the hub assembly to disengage when excessive rotational force is detected, providing automatic protection against motor failure while maintaining reliable engagement during normal charging operations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The decoupling assembly is pre-positioned to engage automatically when motor failure occurs, providing beforehand protection against damage. This safety mechanism is already in place before motor failure happens, preventing harmful force transfer without requiring active control systems.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Object-affected harmful factors

If a decoupling mechanism is added to prevent damage from motor failure, then apparatus protection is improved, but the device complexity increases

Engineering Contradiction:
Improvemotor failure damageVSAvoidcharging assembly complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The decoupling assembly is merged with the existing over-running clutch assembly, sharing common components and integration points. This combining approach minimizes the increase in device complexity by utilizing already-present structural elements rather than adding entirely separate protection systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The decoupling assembly operates automatically based on the mechanical state of the motor and clutch assembly, without requiring external control systems or additional sensors. The mechanism self-activates when motor failure conditions are detected, reducing complexity by eliminating the need for complex control circuits or monitoring systems.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2143118B1Motor operator de-coupling system sensing camshaft position
Publication Date: 2011.02.23 EATON CORP
  • EP2143118B1 patent drawingFigure 1
  • EP2143118B1 patent drawingFigure 2
  • EP2143118B1 patent drawingFigure 3A

AI summary

A decoupling assembly (200) structured to decouple the charging motor (70) and the charging assembly cam shaft (74) is provided. The decoupling assembly (200) includes a lifter pin assembly (220) and an elongated second end (212) to a link member (172) in the over-running clutch assembly (140). The link member (172) supports a pawl (178) which engages an over-running clutch assembly sprocket (142). The pawl (178) is disposed on one side of a link member (172) that is pivotally attached to an over-running clutch assembly hub assembly (144). The link member (172) is structured to pivot in a "see-saw" like manner and thereby move the pawl (178) between a first position, wherein the pawl (178) engages the sprocket (142), and a second position, wherein the pawl (178) does not engage the sprocket (142). The lifter pin assembly (220) includes a lifter pin (222) that is structured to engage the link member second end (212) and thereby move the pawl (178) between the first position and the second position.