Blow Pin Alignment Adjusting Members for Parison Sealing
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Solution Overview
Problem
In extrusion blow molding, misalignment between the blow pin shaft and the centerline of the forming die leads to issues such as damage to the blow pin, perforation of the parison, inadequate sealing, and incomplete expansion due to lack of parallelism, causing operational inefficiencies and potential damage.
Innovation Solution
The implementation of a blow molding apparatus with at least three adjusting members to ensure substantial parallelism between the blow pin shaft and the centerline of the forming die, and between the sealing element and the parison opening, using threaded portions to achieve precise orientation of the actuator and support members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the blow pin shaft is rigidly connected to the actuator rod without adjusting means, then the structure is simple, but misalignment occurs between the blow pin shaft and the centerline of the forming die
Solution Approach 1:
The patent introduces adjusting means between the actuator mounting and the blow pin shaft to allow dynamic adjustment of the blow pin shaft's lateral position and orientation. This enables the system to adapt to manufacturing tolerances and achieve proper alignment without requiring complex rigid connections, resolving the contradiction between structural simplicity and alignment precision.
Solution Approach 2:
The adjusting means allow modification of the blow pin shaft's position parameters (lateral offset and angular orientation) relative to the actuator rod and forming die. By enabling parameter adjustment, the system can compensate for misalignment while maintaining a relatively simple overall structure, balancing device complexity with manufacturing precision.
2Manufacturing precision
If adjusting means are added to align the blow pin shaft with the forming die centerline, then alignment precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the alignment function into separate adjusting mechanisms positioned between the actuator mounting and the blow pin shaft. This segmentation allows independent adjustment of lateral position and angular orientation, achieving precise alignment while keeping each adjusting component simple and modular, thus limiting the increase in overall device complexity.
3Ease of manufacture
If the blow pin shaft is not parallel to the forming die centerline, then manufacturing is easier, but the blow pin causes damage to the parison or fails to seal properly
Solution Approach 1:
The adjusting means are configured to be set during the assembly process before operation begins. This preliminary adjustment ensures that the blow pin shaft is properly aligned with the forming die centerline and that the blow pin will seal correctly against the parison, preventing damage and ensuring reliable sealing while maintaining ease of assembly.
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 solution ensures accurate alignment and sealing, preventing pressurized fluid bypass and binding issues, resulting in complete expansion and improved quality of the blow-molded articles by maintaining parallelism and proper orientation of the blow pin and sealing elements.
Implementation Method 1
The adjusting members may each comprise a threaded portion engaged with at least one of an actuator mounting member to which the actuator is attached and a support member so that rotation of the adjusting member is converted to relative translation of the actuator mounting member and support member
Data Source
AI summary
A blow molding apparatus wherein an extruded tubular parison is pressurized to form a molded article, comprises a blow pin for introducing pressurized fluid into the parison, an actuator for advancing and retracting the blow pin and adjusting means for determining the orientation of the actuator to achieve substantial parallelism of a blow pin shaft to which the blow pin is attached and a centerline of the opening through a forming die through which the blow pin shaft passes and to achieve substantial parallelism of a sealing element of the blow pin with a plane transverse to the opening of the parison.