Cartridge Liquid Injector With Dynamic Reduction Ratio Switching

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Solution Overview

Problem

Conventional cartridge liquid injectors require manual operation to return the plunger, leading to insanitation issues and a need for an electrically driven solution that can quickly reverse the plunger's direction.

Innovation Solution

The cartridge liquid injector incorporates a reduction ratio switching mechanism using a gear group that adjusts the reduction ratio based on the plunger's direction and cartridge attachment state, allowing for automatic speed adjustment and motor direction switching to enable quick electrical driving of the plunger's return.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If the motor with reduction device is used to return the plunger, then the plunger can be moved backward automatically, but the returning process takes too long

Engineering Contradiction:
Improveautomatic plunger returnVSAvoidplunger return time
Core Design Contradiction:
Extent of automationVSLoss of time

Solution Approach 1:

The reduction ratio is dynamically changed based on the plunger's position and movement direction. When the plunger needs to be returned, the reduction ratio switching portion switches to a lower reduction ratio, enabling the motor to rotate faster and return the plunger quickly. This dynamic adjustment resolves the contradiction between automated operation and time consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the reduction ratio parameter according to the operational phase. During injection, a higher reduction ratio provides precise low-speed control. During return, a lower reduction ratio enables fast rotation. This parameter change allows the same motor to achieve both precise injection and rapid return without manual intervention.

Inventive Principle:
Principle #35Parameter changes

2Speed

If the plunger is pushed back with hands, then the returning process is quick, but insanitation occurs

Engineering Contradiction:
Improveplunger return speedVSAvoidinsanitation
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The system uses itself to return the plunger through automated electrical driving. The motor with reduction device, controlled by the reduction ratio switching portion, automatically returns the plunger without requiring manual contact. This self-service approach eliminates insanitation while maintaining quick return speed.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If a high reduction ratio is used for pushing forward the plunger, then precise low-speed injection is achieved, but the return speed becomes slow

Engineering Contradiction:
Improveinjection precisionVSAvoidplunger return speed
Core Design Contradiction:
Manufacturing precisionVSSpeed

Solution Approach 1:

The reduction ratio is dynamically adjusted based on the operational phase. During the injection phase, a high reduction ratio provides precise low-speed control. During the return phase, the reduction ratio switching portion switches to a lower reduction ratio, enabling fast rotation and quick plunger return. This dynamic switching resolves the speed-precision contradiction.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The operational cycle is segmented into injection phase and return phase, each with optimized reduction ratios. The reduction ratio switching portion divides the motor's rotational output into different speed ranges suitable for different phases, allowing precise injection and rapid return to occur sequentially with optimal performance in each phase.

Inventive Principle:
Principle #1Segmentation

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 solution allows for rapid and sanitary automatic return of the plunger, improving efficiency and reducing the time required for the plunger's reverse motion, addressing the insanitation and speed limitations of conventional devices.

Implementation Method 1

a reduction gear group having a plurality of gears (4b, 6b, 6c) coupled to each other

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 2

a rack member (7) selectively engageable with one of the slow speed gear and fast speed gear for moving the rack member linearly

Methodology Applied
Scientific EffectRack and pinion mechanism: Rack and Pinion

Data Source

PatentEP2014323B1Cartridge liquid injector
Publication Date: 2010.10.06 NIPRO CORP
  • EP2014323B1 patent drawingFigure 1
  • EP2014323B1 patent drawingFigure 2
  • EP2014323B1 patent drawingFigure 3~5

AI summary

A cartridge liquid injector includes a drive motor (3) rotatable in forward and reverse directions, for applying driving force, a reduction portion (4) reducing a speed of rotational output of the drive motor (3), a linear motion portion (5) converting rotational output of the reduction portion (4) to linear motion, a plunger (9) pushed forward or pulled back by the linear motion portion (5) to move forward an injection plug (11b) of a cartridge (11a), and a reduction ratio switching portion (6) switching a reduction ratio of the reduction portion (4) such that the reduction ratio in pulling back the plunger (9) is lower than the reduction ratio in pushing forward the plunger (9).