Vehicle Battery Cutout Switch with Segmented Contacts
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Solution Overview
Problem
Battery cutout switches in vehicles and boats experience fretting corrosion and micro-interruptions due to vibrations, causing damage to contact surfaces and electrical discharges.
Innovation Solution
A switch design featuring a contact-holder body with movable electrical contacts that rest on fixed contacts at three points, utilizing compression springs and a cam mechanism to stabilize contact pressure and resist oscillatory movements, reducing the risk of fretting corrosion and micro-interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a movable electrical contact is elastically pushed against fixed contacts by an elastic force, then the contact pressure is maintained, but vibrations and elastic force cause oscillating movements leading to fretting corrosion and micro-interruptions
Solution Approach 1:
The movable electrical contact is divided into two separate contacts instead of being a single piece. This segmentation allows each contact to be independently positioned and stabilized, reducing the oscillatory movements that cause fretting corrosion while maintaining reliable electrical connection.
Solution Approach 2:
The two movable contacts are preliminarily positioned at specific locations on the contact-holder body before operation. This preliminary positioning ensures they rest stably on the fixed contacts, preventing vibrations from causing harmful oscillations during use.
2Device complexity
If a single movable contact is used, then the structure is simple, but it produces micro-interruptions and electrical discharges causing contact surface damage
Solution Approach 1:
The single movable contact is segmented into two separate movable contacts. This increases structural complexity slightly but dramatically improves reliability by eliminating micro-interruptions and electrical discharges through the distributed contact points.
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 effectively prevents fretting corrosion and micro-interruptions, ensuring stable contact pressure and reliable electrical connectivity despite vibrations, thereby extending the lifespan of the switch contacts.
Implementation Method 1
The contact-holder body 28 is subject to an elastic force that tends to push the contact-holder body towards the open electrical contacts position
Implementation Method 2
The movable electrical contact, in the closed contacts position, is elastically pushed against the fixed electrical contacts
Data Source
Figure 1
Figure 2
Figure 3~7
AI summary
A switch, in particular a battery cutout switch for vehicles and the like, comprising: - an insulating housing (12) carrying at least two fixed electrical contacts (22), - a contact-holder body (28) movable relative to the housing (12) along a rectilinear direction (A) between a closed contacts position and an open contacts position, - at least one movable electrical contact (32) carried by said contact-holder body (28) and having a first and a second contact zone (70, 72), cooperating with the head portions (23) of the respective fixed electrical contacts (22), wherein said first contact zone (70) of said movable electrical contact (32) has two protuberances (76) with curved contact surfaces that establish two points of contact with the head portion (23) of the respective fixed electrical contact (22), and said second contact zone (72) has a single protuberance (78) with a curved contact surface that establishes a single point of contact with the head portion (23) of the respective fixed electrical contact (22), so that in the closed contacts position, said movable electrical contact (32) is in contact with said fixed electrical contacts (22) at three points.