Change-over Contact Piece Assembly for Consistent Pressure

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Solution Overview

Problem

Existing contact piece assemblies in auxiliary switches face challenges in maintaining consistent contact pressure between movable and stationary contacts, leading to instability and reliability issues due to manufacturing tolerances and material considerations.

Innovation Solution

A change-over contact piece assembly design featuring a movable contact carrier with clamping portions, extensions, and a reset member, which rotates to ensure consistent contact pressure by using locating protrusions and accommodation grooves, reducing the impact of mechanical tolerances and enhancing stability and current-carrying capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a movable contact piece is used in a single-break change-over contact piece assembly, then switching between different electrical circuits is achieved, but it is difficult to maintain consistent contact pressure with stationary contact pieces on upper and lower sides

Engineering Contradiction:
Improveswitching capabilityVSAvoidcontact pressure consistency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The movable contact assembly is segmented into a movable contact carrier and a movable contact piece, allowing independent optimization of each component's function and contact pressure distribution

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The movable contact carrier acts as an intermediary between the movable contact piece and stationary contacts, providing a stable mounting platform that ensures consistent contact pressure through precise positioning structures

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If manufacturing tolerances and material variations are considered, then production flexibility is improved, but contact piece pressure consistency deteriorates

Engineering Contradiction:
Improveproduction flexibilityVSAvoidcontact pressure uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The clampable connection structure employs asymmetric design elements that compensate for manufacturing tolerances, ensuring consistent contact pressure despite variations in production dimensions

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The connection structure incorporates built-in tolerance compensation mechanisms that preemptively account for manufacturing variations, maintaining contact pressure consistency before assembly errors can affect performance

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

3Reliability

If the movable contact carrier has a large current-carrying section, then current-carrying capacity is improved, but device complexity increases

Engineering Contradiction:
Improvecurrent-carrying capacityVSAvoidcarrier structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The movable contact carrier is designed as a multi-functional component that simultaneously provides mechanical support, electrical conduction, and positioning functions, reducing overall device complexity while maintaining large current-carrying capacity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The carrier integrates the current-carrying path with the mechanical support structure, merging electrical and mechanical functions into a single component that reduces part count and assembly complexity

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3340271B1Change-over contact piece assembly and auxiliary switch with same
Publication Date: 2019.10.16 SIEMENS AG
  • EP3340271B1 patent drawingFigure 1
  • EP3340271B1 patent drawingFigure 2
  • EP3340271B1 patent drawingFigure 3

AI summary

The present invention discloses a change-over contact piece assembly, comprising: a first stationary contact piece with a first stationary contact provided thereon; a second stationary contact piece with a second stationary contact provided thereon; and a movable contact piece assembly comprising: a movable contact carrier connectable to a rotary member; a movable contact fixed on the movable contact carrier; and a reset member, with one end thereof being connected to the movable contact carrier, and the other end thereof being connected to the rotary member, wherein as the rotary member rotates, the movable contact can be driven into contact with the first stationary contact or the second stationary contact. The present invention further provides an auxiliary switch having the above-mentioned change-over contact piece assembly. With the change-over contact piece assembly of the present invention, it can be ensured that the movable contact carrier applies the same contact piece pressure to stationary contact pieces on upper and lower sides, thereby ensuring the stability of electrical contact between the movable contact and the stationary contacts.