Trigger Switch Contact Mechanism to Prevent Chattering
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Solution Overview
Problem
The seesaw type movable contact piece in trigger switches experiences slippage during contact and separation, leading to irregular open/close characteristics, low contact pressure, and chattering, which reduces reliability and causes wear.
Innovation Solution
A contact mechanism with a pair of movable contact pieces, where one is biased by a spring for pressure contact with a fixed contact, and the other is rotated by an operating element for pressure contact with a current-passing fixed contact, ensuring consistent contact pressure and preventing chattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seesaw type movable contact piece is used to ensure contact pressure, then chattering is prevented and contact reliability is improved, but slippage occurs in contact timing and open/close characteristics become irregular
Solution Approach 1:
The movable contact piece is divided into two separate contact pieces: a first movable contact piece for ensuring contact pressure and a second movable contact piece for precise contact timing. This segmentation allows each contact piece to independently fulfill its specific function without interference, resolving the contradiction between contact reliability and open/close characteristic precision.
Solution Approach 2:
A movable contact terminal is introduced as an intermediary component that rotatably supports both movable contact pieces. This intermediary structure enables independent rotation and positioning of each contact piece, allowing the first contact piece to provide contact pressure while the second contact piece maintains precise contact timing, thus resolving the contradiction.
2Object-affected harmful factors
If contact pressure is increased to prevent chattering, then vibration resistance is improved, but arc generation increases and contact surface wear occurs
Solution Approach 1:
The contact function is segmented into two separate contact pieces: the first movable contact piece applies contact pressure to prevent chattering and improve vibration resistance, while the second movable contact piece is designed to minimize arc generation. This segmentation allows optimization of each contact piece for its specific function, resolving the contradiction between vibration resistance and arc generation.
Solution Approach 2:
Different contact pieces are designed with different local qualities: the first movable contact piece has properties optimized for maintaining contact pressure and preventing chattering, while the second movable contact piece has properties optimized for reducing arc generation and minimizing surface wear. This local quality differentiation resolves the contradiction between vibration resistance and arc generation.
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 eliminates slippage and irregularities in contact timing, enhances vibration resistance, and prolongs contact lifespan by maintaining high contact reliability and preventing arc generation.
Implementation Method 1
an open/close movable contact piece (37) which is biased in a contact closing direction by a spring member (38)
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A contact mechanism is provided where vibration resistance canbe increased and, particularly, chattering during an operation can be prevented so that contact reliability is high, and no irregularity occurs in an open/close characteristic. Apair of movable contact pieces is supported on a movable contact terminal such that the pair of movable contact pieces is rotatable along with the reciprocation of an operating element. An open/close movable contact is mounted on an open/close movable contact piece which forms one of the movable contact pieces and is rotatably biased by a spring member. A current-passing movable contact is mounted on a current-passing movable contact piece which forms the other of the movable contact pieces. By moving the operating element, a restriction imposedonaposition of the operating element is released so that the open/close movable contact piece is rotated by a spring force of the spring member whereby the open/close movable contact is brought into pressure contact with an open/close fixed contact mounted on afixedcontact terminal. On the other hand, the current-pass ing movable contact piece is rotated by the operating element so that the current-passingmovable contact is brought into pressure contact with a current-passing fixed contact mounted on the fixed contact terminal.