Molding Unit With Fixed Cylinder And Movable Carriage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing molding units for thermoplastic container production by stretch blow molding face challenges in performing the 'boxing' operation efficiently, as they are cumbersome and hinder high-rate series manufacturing due to the weight of the carriage and pneumatic cylinder devices.
Innovation Solution
A molding unit design where the mold bottom is supported by a fixed carriage with a stationary cylinder, utilizing elastic return means and a cam follower system to control movement, allowing for a lightweight carriage and increased production rate without significant power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a pneumatic cylinder is mounted on the carriage to move the mold bottom over the boxing path, then enough force is available to perform the boxing operation, but the carriage weight increases significantly
Solution Approach 1:
The heavy pneumatic cylinder is extracted from the moving carriage and repositioned on the fixed holder. Only the lightweight piston rod remains attached to the carriage, providing the necessary boxing force without the weight penalty of the complete cylinder assembly.
Solution Approach 2:
Instead of mounting the cylinder on the carriage (moving component), the invention inverts the arrangement by mounting the cylinder on the fixed holder and allowing the piston rod to extend to the carriage. This reverses which component is stationary and which is mobile.
2Speed
If a cam actuation device is used to move the mold bottom, then rapid and precise control is achieved, but insufficient force is available to perform the boxing operation
Solution Approach 1:
The invention merges the advantages of both cam actuation and pneumatic actuation. The cam mechanism provides rapid positioning and precise control, while the pneumatic cylinder provides the necessary boxing force. These two systems work together on the same mold bottom actuation mechanism.
3Force
If a heavy carriage with pneumatic cylinder is used to perform boxing operation, then sufficient force is available, but production rate decreases due to cumbersome weight
Solution Approach 1:
The heavy cylinder is extracted from the moving carriage, leaving only the lightweight piston rod attached to the carriage. This extraction removes the source of excessive weight that limited production rate, while the stationary cylinder remains available to provide boxing force when needed.
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 design enables rapid and precise control of the mold bottom movement, achieving high production rates comparable to units without a boxing operation while reducing the weight and power requirements of the carriage, thus enhancing manufacturing efficiency.
Implementation Method 1
first actuation means having elastic return means that exert an elastic return force on the carriage toward its upper molding position
Implementation Method 2
first actuation means have a cam follower that is supported by the carriage and a cam path that works with the cam follower to make the carriage slide to its lower position
Implementation Method 3
second actuation means having at least one cylinder housing a piston sliding vertically that is able to push the mold bottom over its boxing path by pressurizing a lower work chamber of the cylinder
Data Source
AI summary
A molding unit (10) for forming a container made of thermoplastic material, includes: —a mold bottom (16) that is movable between a low position, an intermediate boxing position and a high position; —a carriage (24) that supports the mold bottom (16) and is mounted in a movable manner in a fixed holder (26); —actuation elements for moving the carriage (24) into its intermediate boxing position; —the actuation elements including a cylinder (32) that houses a piston (98) liable to push the mold bottom (16) through a boxing travel; characterized in that the mold bottom (16) is supported in a fixed manner by the carriage (24), the cylinder (32) being fixed with respect to the fixed holder (26). A method for employing the molding unit is also described.