Actuator Rotational Locking Mechanism for Emergency Stop

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Solution Overview

Problem

Emergency stop operators for electric machines often require complex spring-loading and latch mechanisms to prevent accidental return to the inactive position, which can be inefficient and require multiple pushes to activate and deactivate, and are not logically intuitive for operation.

Innovation Solution

An actuator device with a rotational locking mechanism that allows the actuator body to move from a first to a second position by pushing and back to the first position by pulling, using projections and inclined abutment surfaces to stabilize the second part in the second position and prevent longitudinal motion back to the first position without relying on spring-loading or latch mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If spring-loading and latch mechanisms are used to prevent accidental return to inactive position, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improveprevention of accidental returnVSAvoidcomplexity of spring-loading and latch mechanisms

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the spring-loading and latch mechanisms from the actuator device, replacing them with a pure geometric locking system. The rotational locking mechanism uses fixed projections and corresponding recesses that engage purely through geometry, eliminating the need for elastic elements and latch components, thus reducing device complexity while maintaining reliability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using active spring-loading and latch mechanisms to maintain position, the patent inverts the approach by using passive geometric interlocking features. The projections on the holder element and corresponding recesses on the actuator body create a self-locking system where the geometry itself prevents accidental return, rather than relying on active retention mechanisms.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If multiple pushes are required to activate and deactivate the operator, then reliability is improved, but ease of operation deteriorates

Engineering Contradiction:

Improveprevention of accidental activationVSAvoidnumber of pushes required

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent inverts the conventional emergency stop operation by allowing activation through a single push while deactivation requires a pulling motion. The geometric locking mechanism is designed so that pushing the actuator body engages the projections with recesses to lock in the active position, while returning requires a deliberate pulling motion to disengage, providing intuitive and simple operation.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The actuator device uses the operator's own pulling motion to disengage the geometric locking mechanism. The projections and recesses are positioned such that normal pulling of the actuator body automatically disengages the lock and returns it to the inactive position, eliminating the need for complex reset mechanisms or multiple operational steps.

Inventive Principle:

Principle #25Self-service

3Ease of operation

If spring-loading is used to return actuator body to first position, then ease of operation is improved, but reliability deteriorates due to risk of accidental return

Engineering Contradiction:

Improveautomatic return to inactive positionVSAvoidrisk of accidental return

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent removes spring-loading mechanisms entirely, replacing them with a geometric system where the actuator body returns to the inactive position through the operator's pulling motion. The fixed projections on the holder element and corresponding recesses on the actuator body create a deterministic system where return occurs only when the operator deliberately pulls, eliminating accidental return caused by spring failure or insufficient force.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using spring-loading to automatically return the actuator body, the patent inverts the approach by requiring the operator's pulling motion to initiate return. The geometric interlocking features ensure that the actuator body remains stable in the active position during normal operation and only returns when deliberately pulled, providing both ease of operation and high reliability.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS8513557B2Actuator device and an electric switch device provided therewith

Publication Date: 2013.08.20 ABB (SCHWEIZ) AG

AI summary

An actuator device including a holder element provided to be fixed against a device operated on by the actuator device. An actuator body is displaceable in a longitudinal direction along the holder element. A guide member is provided so as to guide the actuator body along the holder element. The actuator body includes a first part that is operable from outside the actuator device, and a second part that is movable in the longitudinal direction in relation to the first part. The actuator body is displaceable to a first, non-actuated position, in which the first part and the second part of the body are movable in the longitudinal direction and a second, actuated position, in which the second part is rotationally displaced in relation to the first part and abuts an abutment surface on the holder element such that motion of the second part in the longitudinal direction towards the first position is inhibited. The first part includes a rotational locking member that engages the second part in the second position and locks the second part rotationally in the second position.