Torsion Coil Spring Switch Actuation for Compact Long Stroke

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Solution Overview

Problem

Switch devices require a longer stroke for power generation, but using compression coil or plate springs increases device size, and smaller springs fail to achieve intended lifetime, operation load, and stroke.

Innovation Solution

A switch device with a torsion coil spring acting between an actuation unit and a movable unit, allowing the actuation unit to move between positions with a force direction change, enabling a longer stroke while reducing device size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a compression coil spring or plate spring is used for returning movement, then the intended lifetime and operation load are achieved, but the size of the switch device increases

Engineering Contradiction:
ImprovelifetimeVSAvoidsize of switch device
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent changes the fundamental parameter of spring type from compression coil spring or plate spring to torsion coil spring. This parameter change allows the spring to function effectively in a different configuration (rotational/torsional rather than linear compression), enabling the same return function with reduced size constraints while maintaining lifetime and operation load requirements.

Inventive Principle:
Principle #35Parameter changes

2Volume of stationary object

If a smaller compression coil spring or plate spring is used, then the size of the switch device is reduced, but the intended lifetime and operation load cannot be achieved

Engineering Contradiction:
Improvesize of switch deviceVSAvoidlifetime
Core Design Contradiction:
Volume of stationary objectVSReliability

Solution Approach 1:

The invention changes the spring type parameter to torsion coil spring, which has different mechanical characteristics suitable for compact designs. The torsion mechanism allows for more efficient space utilization while maintaining the necessary mechanical strength and fatigue resistance for the intended lifetime and operation load.

Inventive Principle:
Principle #35Parameter changes

3Power

If a longer stroke is set for the member that moves in response to an operation, then the amount of power generation increases, but the size of the switch device increases

Engineering Contradiction:
Improvepower generationVSAvoidsize of switch device
Core Design Contradiction:
PowerVSVolume of stationary object

Solution Approach 1:

The patent transitions from linear motion (compression spring) to rotational/torsional motion (torsion coil spring). This dimensional change allows the actuation unit to achieve a longer effective stroke through rotational movement, increasing power generation capability while maintaining a compact device footprint since the torsion spring occupies less space than a linear compression spring of equivalent capacity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

The solution allows for a longer stroke and reduced size of the switch device, enhancing power generation efficiency and extending the lifetime of the springs.

Implementation Method 1

a torsion coil spring that acts between the actuation unit and the movable unit

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Data Source

PatentEP3258474B1Switch device
Publication Date: 2021.05.05 OMRON CORP
  • EP3258474B1 patent drawingFigure 1
  • EP3258474B1 patent drawingFigure 2A~2H
  • EP3258474B1 patent drawingFigure 3

AI summary

A switch device is small and has a long stroke set for a member that moves in response to an operation. The switch device includes an actuation unit (12), a movable unit (13), a first base (14), and a second spring (2), which is a torsion coil spring that acts between the actuation unit and the movable unit. The movable unit is movable with respect to the base. The second spring applies a force to the actuation unit when the actuation unit is at a third position in a direction that is not parallel to a direction in which the torsion coil spring applies a force to the actuation unit when the actuation unit is at a fourth position.