Trigger Switch Air Pressure Stabilizing Mechanism

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Solution Overview

Problem

Existing trigger switches in electric tools face issues with dust and moisture ingress due to air pressure changes and lack of air escape mechanisms, affecting operational smoothness and reliability.

Innovation Solution

Incorporation of a communication hole with a spherical ball or thin film sheet to stabilize air pressure and prevent dust and moisture entry, featuring a discharge port to release air and a plunger-engaging portion to manage air pressure fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the case and cover are sealed with adhesive agent, then dust-proof and waterproof properties are improved, but air pressure changes occur when trigger is operated affecting switching action

Engineering Contradiction:
Improvedust-proof and waterproof propertiesVSAvoidswitching action smoothness
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The sealed case is segmented by introducing communication holes at strategic locations - one near the switch mechanism and another at the distal end of the plunger. This segmentation allows controlled air flow paths that prevent pressure buildup while maintaining overall sealing integrity against dust and moisture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The plunger acts as an intermediary element with an integrated communication hole system. It mediates between the sealed switch chamber and the external environment, allowing air to escape through the distal end opening while preventing direct entry of dust and moisture into the switch mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Extent of automation

If the trigger reciprocates to operate the switch, then switching function is achieved, but air compression occurs in the sealed interior affecting operation

Engineering Contradiction:
Improveswitching functionVSAvoidair pressure in switch chamber
Core Design Contradiction:
Extent of automationVSStress or pressure

Solution Approach 1:

The communication hole is preliminarily positioned in the plunger to anticipate and prevent air compression issues before they occur. As the plunger moves during trigger operation, air can escape through the pre-positioned communication hole, preventing pressure buildup that would otherwise interfere with switching action.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If communication hole is provided in plunger, then air pressure stabilization is improved, but dust and moisture may enter through communication hole

Engineering Contradiction:
Improveair pressure stabilityVSAvoiddust and moisture entry
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

A flexible membrane is introduced to cover the communication hole in the plunger. This thin flexible film allows air pressure equalization while physically blocking dust and moisture particles from entering through the communication hole, thus maintaining both air stability and contamination protection.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The communication hole at the distal end of the plunger has different functional requirements than the switch chamber. By providing selective coverage with flexible membrane only at the communication hole location, the design achieves local quality differentiation - allowing air flow where needed while blocking contaminants at vulnerable points.

Inventive Principle:
Principle #3Local quality

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 dust and moisture ingress, maintaining operational smoothness by stabilizing air pressure and ensuring reliable switching actions in electric tools.

Implementation Method 1

a spherical ball is provided in the interior of the communication hole in terms of dust proof, and dust and moisture contained in air flowing through the communication hole may be blocked

Methodology Applied
Scientific EffectPhysical barrier blocking: Filter (physical)

Implementation Method 2

a thin film sheet configured to allow air to pass therethrough and block moisture and dust is arranged at an end of the communication hole

Methodology Applied
Scientific EffectSelective permeability: Semipermeable Membrane

Implementation Method 3

the switch mechanism 14 includes an air pressure stabilizing mechanism configured to cancel an air compressing action in the interior of the switch chamber caused by the switch mechanism moving in the interior of the switch chamber

Methodology Applied
Scientific EffectPressure stabilization:

Implementation Method 4

the plunger-engaging portion of the trigger is provided with the discharge port communicating with the communication hole and configured to release air from the communication hole

Methodology Applied
Scientific EffectAir discharge:

Data Source

PatentEP2835807B8Trigger switch
Publication Date: 2018.11.28 SATORI ELECTRIC CO LTD

AI summary

Disclosed a trigger switch having high dust-proof properties and waterproof properties. It includes: a case (11) having a switch chamber (12) in which a switch mechanism (14) is arranged in a sealed state; a plunger (13) inserted into a shaft hole (15) formed on one end side of the case (11) freely slidable, coupled to the switch mechanism (14), and biased forward; and a trigger (21) used for operating the switch by engaging and locking a distal end of the plunger (13), wherein the switch mechanism (14) includes an air pressure stabilizing mechanism configured to cancel an air compressing action in the interior of the switch chamber (12) caused by the switch mechanism moving in the interior of the switch chamber. The air pressure stabilizing mechanism includes a communication hole (16) extending from a rear end opening facing the switch chamber (12) to a distal end opening on the plunger (13), and a plunger-engaging portion (22) of the trigger includes a discharge port (24) communicating with the communication hole (16) and configured to release air from the communicating hole.