Multi-Stage Fluid Actuator for Blow Molding Nozzle Control
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Solution Overview
Problem
Prior art fluid operated actuators in blow molding systems face challenges in maintaining concentricity and cushioning the impact of the nozzle as it contacts the preform, leading to potential damage due to high-speed operation and lack of effective impact cushioning.
Innovation Solution
A multiple-stage fluid operated actuator with a multiple-piece piston assembly is introduced, featuring a housing with varying bores and pistons that separate into distinct fluid chambers, allowing for controlled pressurization and exhaustion to maintain concentricity and cushion the nozzle's impact through increased pressure in an airtight chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large piston head is used to increase the speed at which the nozzle can be lowered, then the productivity is improved, but the manufacturing precision deteriorates as it becomes increasingly difficult to maintain concentricity of the piston within the bore
Solution Approach 1:
The piston is divided into multiple segments (first piston head, second piston head, intermediate section) that can move independently or in coordination. This segmentation allows each segment to be optimized for different functions: the first piston head for high-speed movement and the second piston head for precision positioning and concentricity maintenance, thereby resolving the contradiction between productivity and manufacturing precision.
Solution Approach 2:
The patent employs dynamic control of the piston segments where the intermediate section can extend or retract based on operational requirements. During high-speed lowering, the intermediate section retracts to reduce the effective piston head size and improve concentricity maintenance, while during precision positioning, it extends to provide the necessary stability and control, thus dynamically balancing speed and precision requirements.
2Productivity
If a large piston head is used to increase the speed of travel, then the productivity is improved, but the object-affected harmful factors worsen as the nozzle impacts the preform with a relatively high amount of force
Solution Approach 1:
The patent incorporates a cushioning mechanism through the multi-segment piston design where the intermediate section and second piston head act as a cushioning system. As the first piston head drives the nozzle at high speed, the intermediate section extends to provide gradual deceleration before the nozzle contacts the preform, thereby cushioning the impact and reducing harmful forces while maintaining high productivity.
Solution Approach 2:
The dynamic extension and retraction of the intermediate section allows the system to optimize between high-speed travel and impact cushioning. During the approach phase, the intermediate section is retracted to maximize speed, and during the final positioning phase, it extends to provide progressive deceleration and impact absorption, thus dynamically managing the trade-off between productivity and harmful impact forces.
3Productivity
If a large piston head is used to increase the speed of travel, then the productivity is improved, but the reliability deteriorates due to premature damaging of the nozzle, the preform, or both
Solution Approach 1:
The multi-segment piston design with the intermediate section and second piston head provides a built-in cushioning system that activates before nozzle-preform contact. This beforehand cushioning mechanism progressively reduces the impact velocity, preventing premature damage to the nozzle and preform while maintaining the high-speed travel capability needed for productivity, thus resolving the contradiction between productivity and reliability.
Solution Approach 2:
By segmenting the piston into multiple functional heads and an intermediate section, the system can isolate the high-speed movement function from the precision contact function. The first piston head handles high-speed travel for productivity, while the second piston head and intermediate section handle the controlled deceleration and precise positioning, protecting the nozzle and preform from damage and thereby improving reliability without sacrificing productivity.
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
The solution effectively maintains concentricity and cushions the nozzle's impact, reducing the risk of damage to the nozzle and preform by distributing force more evenly, thereby improving the reliability and precision of the blow molding process.
Implementation Method 1
increased pressure in an airtight chamber... cushioning the impact of the nozzle as it reaches the end of travel
Implementation Method 2
fluid operated actuator comprises a housing including a first bore with a first cross-sectional area and a second bore with a second cross-sectional area... pressurizing the first fluid chamber
Data Source
AI summary
A multiple-stage fluid operated actuator (100) is provided. The multiple-stage fluid operated actuator (100) comprises a housing (101) including a first bore (212) with a first cross-sectional area and a second bore (215) with a second cross-sectional area. The multiple-stage fluid operated actuator (100) further comprises a piston assembly (210) including a first piston (210a) movable within the first bore (212) and a second piston (210b) movable within the first and second bores (212, 215). The piston assembly (210) separates the first and second bores (212, 215) into a first fluid chamber (214a) selectively in fluid communication with a pressurized fluid source (220) or an exhaust, an airtight second fluid chamber (214b), and a third fluid chamber (214c) selectively in fluid communication with the pressurized fluid source (220) or the exhaust.