Extruder Piston Rod Stripping Mechanism for Feed Protection

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Solution Overview

Problem

Existing squeezing devices for containers with masses, such as mortar or sealing materials, suffer from contamination of the piston rod, which can damage the feed mechanism and reduce the device's service life due to adhering dirt and residues.

Innovation Solution

The piston rod is equipped with teeth, and a stripping element with a recessed edge is used to remove dirt and contaminants, preventing them from entering the feed mechanism, while a housing with strategically placed stripping elements and outlet openings ensures effective dirt removal and protection of the feed mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the piston rod is advanced or retracted without protection, then the feeding mechanism can operate continuously, but dirt and contaminants adhere to the piston rod and penetrate into the feed mechanism causing damage

Engineering Contradiction:
Improveservice life of squeezing deviceVSAvoidcontamination of feed mechanism
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A stripping element is introduced as an intermediary component between the piston rod and the feed mechanism. This stripping element with its stripping edge contacts the piston rod surface to remove contaminants, preventing dirt from entering the feed mechanism while allowing continuous operation

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The stripping element performs preliminary cleaning action on the piston rod surface before the piston rod enters the feed mechanism area. By removing contaminants in advance during the advancement and retraction cycles, the feed mechanism is protected from contamination and damage

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a stripping element is added to remove dirt from the piston rod, then contamination of the feed mechanism is prevented, but the device complexity increases

Engineering Contradiction:
Improveprotection of feed mechanismVSAvoidnumber of components in squeezing device
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The stripping element is designed with a localized stripping edge that contacts only the specific area of the piston rod where contaminants accumulate. This targeted approach provides effective cleaning with minimal additional components, avoiding unnecessary complexity in the overall device structure

Inventive Principle:
Principle #3Local quality

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 design significantly increases the service life of the squeezing device by preventing contamination from entering the feed mechanism, reducing wear and tear, and ensuring a clean operation.

Implementation Method 1

the at least one stripping element has at least one section with at least one stripping edge which faces the at least one piston rod when the at least one piston rod is in the advanced or retracted position

Methodology Applied
Scientific EffectMechanical Force: Force

Data Source

PatentEP2295152B1Extruder
Publication Date: 2016.10.19 HILTI AG
  • EP2295152B1 patent drawingFigure 1~2
  • EP2295152B1 patent drawingFigure 3~6

AI summary

The device (11) has an accommodating chamber (12) for a container, and a piston rod (13) displaceable with respect to the accommodating chamber. A feed mechanism (21) is provided for feeding the piston rod, and a stripping element has a stripping edge facing the piston rod and extending over a large part of a cross-sectional circumference of the piston rod. A toothing is provided at a side of the piston rod, and a housing is provided for accommodating a part of the feed mechanism. The housing has housing walls comprising through-flow openings for the piston rod.