Trigger Switch Arm Portion Bending for Compact Contact Biasing
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Solution Overview
Problem
Conventional trigger switches face challenges in miniaturization while maintaining reliable contact pressure, leading to reduced operability and reliability due to the limitations of helical and compression springs in existing designs.
Innovation Solution
A miniaturized trigger switch design featuring a chassis with a slide member, a trigger, power-supply and motor output terminals, and a contact mechanism with a movable and fixed contact system where the arm portion is bent to increase the spring length, allowing for proper biasing force without upsizing, and the lever portion is extended inward to minimize external projection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a helical spring is used to bias the movable piece, then the contact mechanism can be simplified, but the trigger switch cannot be miniaturized because the helical spring is extended off the outside of the fixed contact
Solution Approach 1:
The spring is repositioned from an external extension to an internal integration within the movable piece structure. The movable piece is designed with a recess that accommodates the compression spring, allowing the spring to be contained within the trigger switch housing rather than extending outward, thus enabling miniaturization while maintaining the biasing function
2Volume of moving object
If the trigger switch is miniaturized with a shortened compression spring, then the trigger switch size is reduced, but reliability is lowered because sufficient pressure-contact force cannot be obtained to the fixed contact
Solution Approach 1:
The compression spring is nested within the movable piece structure, specifically within a recess formed in the arm portion. This nesting allows the spring to be contained within the compact trigger switch housing while maintaining sufficient length to provide adequate biasing force for reliable contact
3Volume of moving object
If the spring is positioned inside the guide structure, then the trigger switch can be miniaturized, but it is necessary that a spring seat be formed outside the guide structure, increasing complexity
Solution Approach 1:
The spring seat function is merged with the movable piece structure itself. The arm portion of the movable piece is formed with a recess that serves as the spring seat, eliminating the need for a separate spring seat component outside the guide structure and reducing overall device complexity
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 miniaturization while enhancing contact reliability by ensuring sufficient biasing force and maintaining proper contact pressures, thus improving the overall performance and usability of electric tools.
Implementation Method 1
a spring seat receiving one end of a compression spring, the compression spring biasing the spring seat such that the moveable contact is separated from and brought into contact with the fixed contact
Data Source
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AI summary
An aspect of the invention provides a trigger switch which is miniaturized while reliability of a contact mechanism is enhanced. The trigger switch includes a slide member, arm portions, and lever portions. The slide member is slid in a chassis according to manipulation of a trigger. Movable contacts abutting on fixed contacts are provided on opposite sides to the slide members at front ends of the arm portions. The movable contacts are formed by swingably-supported metal plates, and the arm portions are extended from swingably-supported support portions. Spring seats are provided in intermediate portions of the arm portions, each spring seat receives one end of each of compression springs, and the compression springs bias the spring seats such that the arm portions are separated from and brought into contact with the slide member. The lever portions are extended from the support portions toward opposite sides to the arm portions, and the lever portion can abut on the slide member. In the trigger switch, steps are formed in front of and at the back of the spring seat in each arm portion, and each arm portion is bent such that each spring seat is recessed toward an opposite side to the slide member.