Trigger Liquid Dispenser Piston Sealing Against Lateral Force

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Solution Overview

Problem

Conventional trigger-type liquid dispensers experience liquid leakage due to piston tilting when lateral force is applied, compromising sealing performance between the piston and cylinder.

Innovation Solution

A trigger-type liquid dispenser with a coaxial double-wall cylinder configuration and a piston featuring front-side and rear-side sealing pieces, along with outer-circumferential and inner-circumferential support portions that prevent tilting by slidably abutting against the cylinder walls, maintaining a liquid-tight seal even under lateral force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the piston is engaged with the trigger in a conventional configuration, then the pump can be actuated to pressure-feed liquid, but lateral force applied to the trigger causes piston tilting and sealing piece deformation, deteriorating sealing performance and causing liquid leakage

Engineering Contradiction:
Improvetrigger operationVSAvoidsealing performance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The piston is divided into multiple functional segments: a front-side sealing piece, a rear-side sealing piece, and an outer-circumferential-side support portion. This segmentation allows each part to perform its specific function - sealing or support - independently, preventing tilting and maintaining sealing performance even when lateral force is applied to the trigger

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sealing pieces are designed to abut against the inner circumferential surface of the cylinder in the radial direction, while the support portion provides lateral support. This multi-dimensional arrangement of sealing and support elements prevents piston tilting by distributing forces across different spatial dimensions, maintaining reliable sealing under lateral load

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the sealing piece protrudes radially to seal between the piston and cylinder, then sealing is achieved, but lateral force causes excessive deformation of the sealing piece, compromising the seal

Engineering Contradiction:
Improvesealing performanceVSAvoidsealing piece resistance to deformation
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The outer-circumferential-side support portion acts as an intermediary element between the piston and the cylinder wall. It receives and distributes lateral forces before they can reach the sealing pieces, thereby protecting the sealing pieces from excessive deformation while maintaining their sealing function

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The support portion is positioned to abut against the inner circumferential surface of the cylinder in advance, providing preemptive lateral support to the piston. This beforehand cushioning prevents lateral force from being transmitted to the sealing pieces, protecting them from deformation before it can occur

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 support portions effectively absorb lateral loads, preventing piston tilting and ensuring stable sealing, thereby preventing liquid leakage and maintaining dispensing performance.

Implementation Method 1

an outer-circumferential-side support portion that is provided integrally in the piston on a front side of the front-side sealing piece and that slidably abuts against the inner circumferential surface of the outer tubular wall

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a front-side sealing piece and a rear-side sealing piece that each are provided integrally in the piston and that each abut against an inner circumferential surface of the outer tubular wall in a liquid-tight manner

Methodology Applied
Scientific EffectContact sealing:

Data Source

PatentEP3225314B1Trigger type liquid dispenser
Publication Date: 2021.10.13 YOSHINO KOGYOSHO CO LTD
  • EP3225314B1 patent drawingFigure 1
  • EP3225314B1 patent drawingFigure 2
  • EP3225314B1 patent drawingFigure 3

AI summary

Proposed is a trigger-type liquid dispenser (1) that, even when lateral force is applied to a trigger (35), prevents liquid leakage. The trigger-type liquid dispenser (1) according to the present disclosure includes a pump (18), which includes: a cylinder (21), which includes an inner tubular wall (19) and an outer tubular wall (20); a piston (23), which has a front-side end portion; a front-side sealing piece (24) and a rear-side sealing piece (25); an outer-circumferential-side support portion (26); and an inner-circumferential-side support portion (27). The outer-circumferential-side support portion (26) is provided with an annular cut-off portion (28), which forms a gap between the outer-circumferential-side support portion (26) and an outer circumferential surface of the piston (23).