Sequential-Piston Discharge Device for Large-Volume, Low-Force Operation

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Solution Overview

Problem

Conventional pressure accumulation-type discharge devices face challenges in achieving large discharge volumes due to longer cylinder strokes and heavier operation forces.

Innovation Solution

A discharge device design featuring a first cylinder, a second cylinder with a larger sectional area, and pistons that slide within these cylinders, along with a holding member and pressure accumulating portion, allows for easy achievement of large discharge volumes by controlled piston movements and reduced operation force through sequential advancement of pistons.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the cylinder stroke is increased to achieve large discharge volume, then the discharge volume increases, but the operation force becomes heavier

Engineering Contradiction:
Improvedischarge volumeVSAvoidoperation force
Core Design Contradiction:
Quantity of substanceVSForce

Solution Approach 1:

The pump chamber is divided into a first pump chamber (24a) and a second pump chamber (4b) with different sectional areas. The first piston (3) and second piston (25) operate sequentially in these chambers, allowing the system to achieve large discharge volume through multiple stages rather than requiring a single long-stroke cylinder, thereby reducing operation force.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first piston (3) performs preliminary pumping action in the first pump chamber (24a) before the second piston (25) operates in the second pump chamber (4b). This sequential preliminary action allows fluid to be progressively moved and pressurized, achieving large discharge volume without requiring the full force needed for a single-stage large-displacement operation.

Inventive Principle:
Principle #10Preliminary action

2Quantity of substance

If the cylinder stroke is increased to achieve large discharge volume, then the discharge volume increases, but the device complexity increases

Engineering Contradiction:
Improvedischarge volumeVSAvoiddevice complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The first pump chamber (24a) and second pump chamber (4b) are merged into a single pump chamber structure that is pressurized as a unit. The holding member (16) simultaneously holds both the first piston (3) and second piston (25), integrating multiple pumping actions into a coordinated system that achieves large discharge volume without proportionally increasing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pump chamber serves multiple functions: it acts as the first pump chamber (24a) when the first piston (3) is operating, and as the second pump chamber (4b) when the second piston (25) is operating. This multi-functionality allows the same space to be used for different stages of the pumping cycle, reducing overall device complexity while maintaining large discharge volume capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enables efficient and vigorous discharge of large volumes with reduced operational effort, preventing liquid dripping and heavy operations.

Implementation Method 1

a first urging member configured to urge the first piston in the advancing direction

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

a second urging member configured to urge the first cylinder in the advancing direction

Methodology Applied
Scientific EffectElastic force: Elasticity

Data Source

PatentEP4628220A1Discharge device
Publication Date: 2025.10.08 YOSHINO KOGYOSHO CO LTD
  • EP4628220A1 patent drawingFigure 1
  • EP4628220A1 patent drawingFigure 2
  • EP4628220A1 patent drawingFigure 3

AI summary

A discharge device (1) including: a first cylinder (24); a first piston (3) configured to slide on the first cylinder (24); a second cylinder (4) having a larger sectional area than the first cylinder (24); a second piston (25) configured to slide on the second cylinder (4); a holding member (16) configured to advance and retract along with the first piston (3), the first cylinder (24), and the second piston (25) with respect to the second cylinder (4) in response to an external operation; an internal flow path (18) through which fluid is discharged in accordance with advancing and retracting movements of the holding member (16) via a pump chamber (18a) defined by the first cylinder (24), the first piston (3), the second cylinder (4), and the second piston (25); and a pressure accumulating portion (17) configured to move the first piston (3) from an open position in which the internal flow path (18) is opened to a closed position in which the internal flow path (18) is closed by urging force in a direction that opposes an increase in internal pressure of the pump chamber (18a) due to advancement of the holding member (16) with respect to the second cylinder (4), wherein, in response to the operation, the holding member (16) advances along with the first piston (3) with respect to the second cylinder (4) and moves the first piston (3) to the open position, and subsequently advances along with the second piston (25).