Extruder Control Unit with Dynamic Piston Return

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Solution Overview

Problem

Existing squeezing devices for bulk containers require complex handling and two-handed adjustments, lack consistent metering, and have structural limitations that can lead to damage, especially when inserting new containers.

Innovation Solution

A control method that detects the piston rod's position after forward movement and adjusts the return travel based on maximum available travel, with a separate power assembly and signal input for the motor, allowing for a compact and inexpensive actuating element, and includes a dosing setting unit, position detection unit, and display unit for precise control and user feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the actuating element is arranged within the connection between the power source and the motor, then the motor power can be switched, but the actuating element must be made sufficiently solid which increases device complexity and space requirements

Engineering Contradiction:
Improvemotor power switching capabilityVSAvoidactuating element structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The actuating element is extracted from the power connection path and relocated to a separate signal input on the control unit. This allows the actuating element to be small and simple (requiring only auxiliary voltage) while the control unit handles the power switching function separately, resolving the contradiction between reliability and device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If a predetermined return travel distance is set for the piston rod, then the mass flow after dispensing can be controlled, but damage may occur to the device when inserting new containers due to insufficient travel adjustment

Engineering Contradiction:
Improvemass flow controlVSAvoiddevice damage risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The return travel distance is made dynamic rather than fixed. The control unit automatically adjusts the return travel based on the detected piston rod position after forward movement. If the piston rod is already near the rearmost position, the return travel is reduced or omitted, preventing damage when inserting new containers while maintaining mass flow control during normal operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A position detection unit provides feedback on the piston rod position after forward movement. This feedback enables the control unit to intelligently determine the appropriate return travel distance, preventing both mass flow issues and potential device damage from excessive return travel.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If two correcting variables must be set by the user, then the device can be adjusted for different container types, but both hands are required during squeezing which reduces ease of operation

Engineering Contradiction:
Improvecontainer type adjustmentVSAvoidhands-free operation capability
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The device performs self-adjustment automatically. Instead of requiring the user to manually set two correcting variables, the control unit automatically determines and adjusts the return travel distance based on position detection feedback, enabling one-handed or hands-free operation while maintaining adaptability to different container types.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2314384B1Extruder
Publication Date: 2014.12.31 HILTI AG
  • EP2314384B1 patent drawingFigure 1~2
  • EP2314384B1 patent drawingFigure 3~5

AI summary

The invention relates to a dispensing device (11) for containers (6) containing materials, comprising a receiving chamber (12) for the container (6), a piston rod (13) displaceable relative to the receiving chamber (12), a motor (21) for moving the piston rod (13), an actuating element (26) for generating a control signal when the actuating element (26) is actuated, and a control unit (31) for controlling the motor (21). The control unit (31) has a power module for connecting the motor (21) to a power supply (19) and a separate signal input that is electrically connected to the actuating element (26). The power module connects the motor (21) to the power supply (19) in response to the control signal at this signal input. The invention further relates to a control method for controlling such a dispensing device (11).