Injection Moulding Core Frame Recess for Compact Ejection
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Solution Overview
Problem
Existing injection-moulding apparatuses for plastic parts are inefficient due to high complexity, cost, and bulkiness, particularly in the arrangement of oil-hydraulic pistons, which hinders the production of compact and lightweight plastic parts.
Innovation Solution
The apparatus is redesigned with a core frame featuring a recess for the ejection plate and reduced oil-hydraulic pistons, either two or one central piston, to minimize dimensions and weight, and simplify the system, allowing quicker moulding operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a set of four oil-hydraulic pistons is used in the ejection zone, then the ejection plate can be moved reliably, but the apparatus becomes bulky and complex
Solution Approach 1:
The patent merges multiple piston functions into a single integrated piston assembly. The single piston incorporates both the ejection function and the core withdrawal function, eliminating the need for separate piston systems. This merging reduces device complexity while maintaining reliability through a unified, coordinated movement mechanism.
Solution Approach 2:
The single piston assembly performs multiple functions: it ejects the finished part from the mould and simultaneously withdraws the core from the plastic part. This multi-functionality reduces the overall number of components needed while maintaining all necessary operational capabilities, directly addressing the complexity issue.
2Ease of operation
If four oil-hydraulic pistons with rigid rods and connecting plates are used, then the ejection plate can be actuated effectively, but the apparatus height and weight increase
Solution Approach 1:
The patent extracts and eliminates the heavy rigid rods and connecting plates from the piston system. By using a single piston with direct actuation, the unnecessary intermediate mechanical elements are removed, significantly reducing the weight of the stationary apparatus components while maintaining effective ejection plate actuation.
Solution Approach 2:
Instead of using multiple pistons connected through rigid rods and plates to the ejection plate, the invention inverts the approach by having a single piston directly connected to the ejection plate through a simplified linkage, eliminating the need for heavy intermediate structural elements.
3Device complexity
If the core frame is designed without a recess for the ejection plate, then the structure is simpler, but the stroke is longer and moulding operation is slower
Solution Approach 1:
The patent implements a recess in the core frame that accommodates the ejection plate, creating a nested structure where the ejection plate moves within the core frame's recessed area. This nesting allows for a shorter stroke distance while maintaining full ejection functionality, thereby increasing moulding operation speed without significantly complicating the core frame structure.
4Reliability
If multiple projecting parts and rigid rods are added to the ejection plate, then the piston connection is more secure, but the apparatus becomes more complex and costly
Solution Approach 1:
The patent extracts and removes the multiple projecting parts and rigid rods from the ejection plate design. By using a single piston with a simplified connection mechanism, the unnecessary intermediate elements are eliminated, reducing manufacturing complexity and cost while maintaining secure piston connection through the streamlined design.
Data Source
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AI summary
An apparatus (11,11',11") for the manufacture of injection-moulded plastic parts is described. The apparatus comprises: a back plate (12,12',12"), a core frame (17,17',17") fixed to the back plate, an ejection plate (13,13',13") and a set of ejection pistons (14,14',14") for moving the ejection plate with respect to said back plate, wherein the core frame is shaped in such a way as to comprise a recess for the ejection plate.