Thermoformer Plug Assist Drive Assembly Simplification
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Solution Overview
Problem
Existing thermoforming apparatus drive mechanisms for advancing plug assists into mold cavities are overly complex, large, and prone to misalignment due to multiple ball screws, which complicates synchronization and exposes components to dirt and lubricant loss.
Innovation Solution
A compact plug assist drive system utilizing a single centrally located roller screw within an enclosing housing, supported by bearings and connected to guide-drive rods with quick connect couplings, eliminating the need for linear bearings and simplifying assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple ball screws are used to drive the platen, then the platen can be driven, but the device complexity increases and synchronization becomes difficult
Solution Approach 1:
The patent combines multiple ball screw drives into a single roller screw drive mechanism. The single roller screw centrally located on the platen eliminates the need for multiple separate ball screws and their interconnecting drive belts, thereby reducing device complexity while maintaining reliable synchronous motion of all plug assists.
Solution Approach 2:
The patent segments the drive function by using a single roller screw that independently drives each plug assist through individual pusher shafts, eliminating the need for complex interconnections between multiple ball screws while maintaining synchronization.
2Area of stationary object
If a large platen is used to accommodate four ball screws, then the ball screws can be mounted, but the overall assembly size increases
Solution Approach 1:
The patent consolidates multiple ball screw mounting locations into a single central roller screw location, dramatically reducing the platen area required for mounting drive components and reducing the overall assembly volume.
3Area of stationary object
If the assembly is large in size, then components can be accommodated, but protective enclosure cannot be provided allowing dirt entry and lubricant escape
Solution Approach 1:
The patent reduces the assembly to a compact size using a single central roller screw, enabling the entire mechanism to be enclosed in a protective housing that prevents dirt entry and lubricant escape while accommodating all drive components.
4Reliability
If multiple ball screws with interconnecting drive belts are used, then synchronization can be attempted, but the assembly becomes overly complex
Solution Approach 1:
The patent eliminates interconnecting drive belts by using a single roller screw that independently actuates each plug assist, maintaining synchronization through the common drive source while removing complex interconnection assemblies.
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 provides a simpler, more compact, and easily disassembled drive mechanism that maintains accurate alignment and protects components from dirt and lubricant loss, enhancing the efficiency and reliability of plug assist operations.
Implementation Method 1
a single centrally located roller screw mounted within an enclosing housing... The roller screw shaft has a protruding lower end which has a sheave mounted thereon receiving a belt driven by a servomotor driven sheave... The upper end of the roller screw nut is held abutting an adapter hub affixed to the drive platen to drive the platen up or down when the screw shaft is rotated by operation of the servo motor
Implementation Method 2
the roller screw shaft supported by a set of bearings mounted within a bearing housing affixed to the underside of a bottom plate
Data Source
AI summary
A plug assist drive assembly for driving plug assists in a thermoforming apparatus includes a single centrally located roller screw assembly enclosed in a housing and driving a third platen mounting the plug assist with a group of guide-drive bars connected to a drive platen which is driven by the roller screw nut. The roller screw assembly is removable by removing screws holding the nut to one hub adapter, the screws accessed through an opening in the housing normally covered with a plate.