Switch Actuator with Variable Resistance for Muscle Fatigue

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Solution Overview

Problem

Electrical device switches with traditional restoring members cause hand muscle cramping during prolonged operation, leading to unreliable switching and increased risk of accidental operation due to high restoring forces, and existing locking mechanisms pose safety hazards.

Innovation Solution

A switch design incorporating a resistance generator with variable resistive forces along the travel path, allowing for modified haptics that reduce muscle load and eliminates the need for locking mechanisms, using magnets and detent structures to create a curved force characteristic that facilitates continuous operation without muscle strain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional restoring member is used to return the actuating element to the off position, then the switch can be reliably turned off, but the high restoring force causes hand muscle cramping during prolonged operation

Engineering Contradiction:

Improvereliable turning off of the switchVSAvoidhand muscle cramping

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The restoring force is segmented into two components: a constant baseline restoring force from the restoring member, and a variable resistive force from the resistance generator that changes along the travel path. This segmentation allows the total force to be optimized for both reliability and ease of operation at different positions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The resistance generator creates a dynamic resistive force that varies depending on the position of the actuating element along the travel path. The resistive force is stronger near the off position to ensure reliable resetting, and weaker near the on position to reduce muscle strain during prolonged operation.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If the restoring force is reduced to ease operation, then hand muscle cramping is reduced, but the switch becomes unreliable and increases risk of accidental operation

Engineering Contradiction:

Improvehand muscle crampingVSAvoidunreliable turning off of the switch

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The resistance generator provides a dynamic resistive force that is position-dependent. Near the off position where reliability is critical, the resistive force is strong to ensure the actuating element returns reliably. Near the on position where accidental operation risk is lower, the resistive force decreases to ease operation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Different force characteristics are applied at different locations along the travel path. The high resistive force is localized near the off position to ensure reliable resetting, while the lower resistive force is present near the on position to reduce muscle strain during continuous operation.

Inventive Principle:

Principle #3Local quality

3Reliability

If locking mechanisms are added to assure operation, then operational reliability is improved, but safety hazards and risk of injury increase

Engineering Contradiction:

Improveoperation of the electrical deviceVSAvoidrisk of injury

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The locking mechanism is completely removed from the system. Instead, the resistance generator creates a force landscape that naturally guides the actuating element to stable positions without mechanical locking, eliminating the safety hazards associated with locking mechanisms while maintaining operational reliability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Mechanical locking mechanisms are replaced with a magnetic resistance system. The resistance generator uses magnetic fields to create position-dependent resistive forces that guide the actuating element to stable positions, replacing mechanical locking with a field-based system that eliminates injury risks.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enables continuous, precise operation of electrical devices with reduced muscle fatigue and eliminates the risk of accidental switching, providing improved haptic feedback and safety by varying the sum of forces acting on the actuating element.

Implementation Method 1

a resistance generator (5) attached to the actuating element (3) and retained between at least one resistance bearing (6) formed on the travel path (2) of the switch housing (1) and at least one floating bearing (7) formed on the actuating element (3)

Methodology Applied

Scientific EffectMagnetic repulsion: Ion Repulsion/Attraction

Data Source

PatentUS9183997B2Switch for an electric device

Publication Date: 2015.11.10 JOHNSON ELECTRIC INTERNATIONAL AG

AI summary

A switch has a housing and an actuating element retained on a travel path in the housing. A restoring member (4) provides a restoring force urging the actuator to an off position at one end of the travel path. A resistance generator provides a resistance force which opposes the restoring force when the actuator is in a fully actuated position to reduce the holding force require to keep the actuating element in the fully actuated position.