Screw Weighing Device Reverse Rotation Control

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Solution Overview

Problem

Conventional weighing devices face difficulties in removing articles stuck between troughs and screws, leading to hygiene issues and potential damage to the articles, which lowers their commercial value.

Innovation Solution

A weighing device with a control unit that switches the rotation direction of the screw between forward and reverse based on torque or rotation speed to easily dislodge stuck articles, allowing for continuous operation without physical or electrical stopping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the screw rotates continuously in one direction to convey the article, then the productivity is improved, but the article may get stuck between the trough and the screw causing hygiene issues and potential damage

Engineering Contradiction:
Improveconveyance efficiencyVSAvoidarticle integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The screw rotation is controlled to alternate between forward rotation (conveyance direction) and reverse rotation (loosening direction). The control unit monitors torque or rotation speed and switches rotation direction periodically when sticking is detected, allowing the screw to both convey articles efficiently and prevent/detach stuck articles through reverse rotation.

Inventive Principle:
Principle #19Periodic action

2Productivity

If the screw rotates at high speed to increase conveyance rate, then the productivity is improved, but the torque increases causing articles to get stuck more easily

Engineering Contradiction:
Improveconveyance rateVSAvoidsticking force
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The control unit monitors torque or rotation speed as feedback signals during screw rotation. When the torque exceeds a threshold or rotation speed drops indicating an article is stuck, the control unit automatically switches the rotation direction to reverse, creating a feedback control mechanism that prevents excessive sticking force while maintaining high conveyance rates during normal operation.

Inventive Principle:
Principle #23Feedback

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

Enables easy removal of stuck articles and reduces damage, ensuring efficient and uninterrupted operation of the weighing device.

Implementation Method 1

a screw that rotates in the trough to convey the article put in the trough toward the weighing unit

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4242603B1Weighing device
Publication Date: 2024.10.16 ISHIDA CO LTD
  • EP4242603B1 patent drawingFigure 1
  • EP4242603B1 patent drawingFigure 2
  • EP4242603B1 patent drawingFigure 3

AI summary

A weighing device (1) has: a weighing unit (WH) that weighs a weight value of an article put from an outside; a trough (21) that extends toward the weighing unit and has an open upper portion; a screw (22) that rotates in the trough (21) to convey the article put in the trough (21) toward the weighing unit; a drive portion (40) that rotates the screw (22); and a control unit (50) that controls the rotation. The control unit (50) causes the screw (22) to convey the article by switching between a first rotation in which the article is conveyed in a direction of approaching the weighing unit and a second rotation in which the article is conveyed in a direction away from the weighing unit, on the basis of a torque generated at the time of the rotation or a rotation speed of the rotation.