Switch Device with Rapid Contact Snap Action
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Solution Overview
Problem
Conventional switches with sliding-type movable contacts rely on the operation speed of the control knob for contact speed, which limits durability and is prone to spark generation and water ingress due to dust and oxide films.
Innovation Solution
A switch design featuring a tiltable control knob and movable contact holder with a sliding surface and elastic contact pieces, utilizing a spring-urged control plunger for rapid contact and separation, ensuring reliable operation and reduced spark generation, and a non-contact state gap for water prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a sliding-type movable contact is used, then the switch structure is simple, but the contact speed depends on control knob operation speed which reduces durability
Solution Approach 1:
The movable contact holder is designed to perform rapid tilting motion about the second pivotal shaft when the control plunger crosses the plane between pivotal shaft axes. This dynamic snap action converts the slow rotational movement of the control knob into rapid contact-making and contact-breaking motion, achieving high contact speed independent of control knob operation speed, thereby improving contact durability
Solution Approach 2:
The control plunger acts as an intermediary mechanism between the control knob and movable contact holder. It converts the rotational motion of the control knob into linear sliding motion along the sliding surface, which then triggers the rapid tilting of the movable contact holder. This intermediary mechanism decouples the contact speed from the control knob operation speed
2Ease of operation
If the movable contact operates slowly, then the control knob operation is smooth, but sparks are generated and oxide films accumulate reducing reliability
Solution Approach 1:
The movable contact holder remains stationary during normal operation and only performs rapid tilting motion when triggered by the control plunger crossing the pivotal shaft plane. This dynamic activation ensures that contact-making and contact-breaking occur rapidly to prevent spark generation and oxide film accumulation, while maintaining smooth control during non-actuation phases
3Volume of moving object
If the gap between contacts is reduced for downsizing, then the switch size is reduced, but water ingress and short circuits become more likely
Solution Approach 1:
The movable contact holder tilts rapidly to create sufficient gap between the movable contact and stationary contact when in the off position. This dynamic positioning ensures that even in a compact switch design, adequate separation distance is maintained during non-actuation to prevent water ingress and short circuits, while allowing reduced overall switch dimensions
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 design achieves rapid and reliable switching with improved durability, reduced spark generation, and prevention of water-induced short circuits, while allowing for downsizing compared to sliding-type switches.
Implementation Method 1
the control plunger is urged by a spring in a direction to abut on the sliding surface
Implementation Method 2
the movable contact is brought into contact with the stationary contact with an impact, thereby effectively removing interjacent objects such as oxide film and dust from between the contact portions
Data Source
AI summary
A control knob is supported on a switch base via a first pivotal shaft. A movable contact holder holds a movable contact, faces an inner side face of the control knob, and is supported on the switch base via a second pivotal shaft. The movable contact holder is provided with a sliding surface which faces the control knob. A control plunger whose tip end slidably abuts on the sliding surface is fitted to the control knob so as to be slidable in a direction perpendicular to an axis of the first pivotal shaft. A spring is provided between the control knob and the control plunger so as to urge the control plunger to a direction to but on the sliding surface. The movable contact is attached to the movable contact holder so as to come into contact with the stationary contact when the movable contact holder is turned to at least one of first and second actuation positions. Thus, it is possible to provide a switch which enables a rapid opening and closing between a movable contact and a stationary contact by imparting a snap action to the movable contact.