Electric Switch Actuator Lever Design for Extended Travel

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Solution Overview

Problem

Existing electric switches with additional actuators face limitations in extending actuating travel without increasing the stress on the switching element, and are prone to damage from improper use forces.

Innovation Solution

The actuating lever is mounted to a side surface and extends over the upper surface of the housing, allowing for additional over-travel without damaging the switching element, with a stop preventing further movement of the actuating plunger and the lever making contact with the housing edge to resist excessive forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the actuating lever is mounted on the side surface and extends over the upper surface of the housing, then the actuating travel is extended with a long over-travel after switching, but the switching element may be damaged by forces from improper use

Engineering Contradiction:
Improveactuating travelVSAvoidswitching element protection
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The actuating plunger serves as an intermediary element between the actuating lever and the switching element. It absorbs and transmits the actuating forces while protecting the switching element from direct exposure to improper use forces. The plunger's linear movement path and connection to the lever create a mechanical buffer that maintains reliability while enabling extended travel.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The stop arranged in the switch housing provides beforehand cushioning by limiting the movement of the actuating plunger. This stop prevents the plunger from moving beyond a certain point, thereby protecting the switching element from damaging forces that could result from excessive actuating travel or improper use, while still allowing for extended operational over-travel.

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

2Length of moving object

If a force is applied to the end of the additional actuator, then the switching travel is increased by a linear factor, but the actuating force required becomes correspondingly lower

Engineering Contradiction:
Improveswitching travelVSAvoidactuating force
Core Design Contradiction:
Length of moving objectVSForce

Solution Approach 1:

The actuating lever is mounted on the side surface of the housing rather than directly on the actuating plunger's axis. This dimensional change in mounting location creates a lever arm that provides mechanical advantage, allowing forces applied at the extended end of the lever to be transformed into effective actuating force on the plunger, thereby increasing switching travel while reducing required actuating force.

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

Solution Approach 2:

The actuating lever is designed to be movable and pivotable with respect to the housing, allowing it to dynamically adjust its position during actuation. This dynamic configuration enables the lever to optimize its mechanical advantage throughout the range of motion, facilitating increased switching travel with reduced actuating force requirements.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If the actuating lever is allowed to move further after switching, then an additional over-travel is permitted, but the switching state changes unintentionally

Engineering Contradiction:
Improveover-travel capabilityVSAvoidswitching state stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The actuating plunger acts as an intermediary that decouples the actuating lever's movement from the switching element. The lever can move freely through its full range including over-travel, while the plunger only transmits force to the switching element within the precise range needed for reliable switching, thereby maintaining switching state stability despite extended lever movement.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The stop in the housing provides beforehand cushioning by defining the precise limit at which the actuating plunger can move. This stop ensures that the switching element is actuated only within the correct range, preventing unintentional switching state changes even when the actuating lever is moved further for ease of operation or to provide tactile feedback.

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

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

This configuration reduces the load on the actuating plunger and lever, enabling extended actuating travel without changing the switching state and preventing damage from improper use forces, while allowing the actuating lever to resist forces through a counterforce.

Implementation Method 1

an actuating lever (4) mounted on and pivotable or otherwise movable with respect to the housing

Methodology Applied
Scientific EffectLever: Lever

Implementation Method 2

For a force acting upon the end of the additional actuator switching travel is increased by an approximately linear factor in relation to the switch without an additional actuator and the actuating force is correspondingly lower

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Implementation Method 3

The resilient actuating lever according to the invention... If yet more force is applied to the actuating lever, the free end of the actuating lever can be bent over the edge, and in doing so the lever of the actuating lever is shortened due to the new contact point at the edge of the housing. The actuating lever is now able to resist the contacting forces through the application of a higher counterforce.

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2908325B1Electric switch with an actuator
Publication Date: 2019.06.19 JOHNSON ELECTRIC INTERNATIONAL AG
  • EP2908325B1 patent drawingFigure 1~3
  • EP2908325B1 patent drawingFigure 4~6

AI summary

An electric switch has a housing with an upper surface (2) through which a actuating plunger (3) extends at a position close to a side surface. The actuating plunger is arranged to operate a switching element disposed inside the housing. An actuating lever is fixed to the side surface adjacent the plunger such that the actuating lever (4) extends over and beyond the upper surface (2) of the housing (1). A stop for the actuating plunger (1) is arranged inside the housing (1). With this switch the actuating travel is extended solely in relation to the switch. Furthermore a long over-travel exists following switching, wherein any forces which might occur through improper use in relation to the switch do not cause any damaging effects to the switching element.