Cellulose Mould Ejector Assembly for Damage-Free Product Release
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Solution Overview
Problem
Existing dry-forming techniques for manufacturing rigid cellulose products face challenges in reliably removing the final product from the moulding tool without causing damage, especially for non-flat shapes, due to the fluffy nature of cellulose fibres and the risk of vacuum conditions leading to tearing or marking.
Innovation Solution
A product forming unit with a pneumatically driven ejector member that is biased towards a retracted position during moulding, allowing for precise engagement and removal of the cellulose product after pressing, using a gas conduit to facilitate the ejector's movement and minimize surface contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a suction device is used to remove the pressed cellulose product from the moulding tool, then the product can be removed from the mould, but the fluffy cellulose fibres may create vacuum conditions causing the product to stick to the mould part, leading to tearing or marking
Solution Approach 1:
The patent replaces the mechanical suction-based removal system with a pneumatic ejection system. Instead of using suction cups that create vacuum conditions and risk tearing the fluffy cellulose product, compressed air is used to blow the product off the moulding tool. This substitution eliminates the harmful vacuum effect while achieving reliable product removal.
Solution Approach 2:
The patent employs pneumatic principles by using compressed air delivered through a gas conduit to eject the pressed cellulose product from the moulding tool. The pneumatic ejection system uses controlled air pressure to reliably remove the product without creating vacuum conditions that would cause sticking or damage to the delicate cellulose fibres.
2Ease of manufacture
If the ejector member is always biased towards the extended position to insert the cellulose blank, then the blank can be inserted, but the ejector member may damage the pressed cellulose product during insertion
Solution Approach 1:
The patent makes the ejector member dynamic by introducing a reversible bias mechanism. Instead of being permanently biased in one position, the ejector member can be temporarily biased towards the extended position during blank insertion, then switched to bias towards the retracted position during pressing. This dynamic adjustment allows the system to adapt to different operational phases, enabling easy blank insertion while protecting the product from damage during pressing.
Solution Approach 2:
The patent implements periodic action by alternating the bias direction of the ejector member according to the manufacturing cycle. During the insertion phase, the bias is towards extension to facilitate blank placement. During the pressing phase, the bias switches to retraction to protect the product. This periodic switching of bias direction optimizes performance for each stage of the manufacturing process.
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
Ensures reliable and damage-free removal of cellulose products, maintaining environmental benefits and reducing energy consumption, while protecting the out-feed device from damage.
Implementation Method 1
an ejector member (28) displaceable between a retracted position and an extended position in relation to the main body of the second mould part (16), wherein said ejector member (28) is biased towards said retracted position by means of a spring element (32)
Implementation Method 2
wherein said ejector member (28) is configured to be pneumatically driven from the retracted position to the extended position in order to engage the cellulose product (2) and remove the pressed cellulose product (2) from the second mould part (16) after the pressing of the cellulose blank (10)
Data Source
Figure 1
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AI summary
The present invention relates to a method and a product forming unit for dry manufacturing rigid cellulose products (2) having essentially non-flat general shape from a cellulose blank. The product forming unit comprising a moulding tool having a first mould part (15) and a second mould part (16), wherein at least one of the first mould part (15) and the second mould part (16) is displaceable in the axial direction in relation to the other in order to press the cellulose blank therebetween into final shape by applying a predetermined pressure P in the axial direction of the moulding tool, and wherein the second mould part (16) of the moulding tool comprises a main body and an ejector assembly having at least one ejector member (28). The at least one ejector member (28) is displaceable between a retracted position and an extended position in relation to the main body of the second mould part (16), wherein said ejector member (28) is biased towards said retracted position and configured to be pneumatically driven from the retracted position to the extended position in order to engage the cellulose product (2) and remove the pressed cellulose product (2) from the second mould part (16) after the pressing of the cellulose blank (10).