Lifting Cam Section for Mandrel Extraction in Container Preform Conveying
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Solution Overview
Problem
High-speed production of containers with non-axisymmetric shapes faces challenges due to involuntary preform rotation during mandrel extraction, leading to reduced production rates and potential damage from incorrectly positioned preforms during the conveying process.
Innovation Solution
A conveying device with a lifting cam section that reduces mandrel extraction time and allows for controlled ejection of incorrectly positioned preforms, utilizing a linear motor and cam follower system to manage the mandrel's active and inactive positions efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the mandrel extraction speed is increased to match the high preform running speed (1 m/s), then production rate is improved, but the preform undergoes involuntary rotation during extraction causing misalignment with the mold
Solution Approach 1:
The cam mechanism is designed to perform the mandrel extraction action in advance and in a controlled manner before the preform reaches the molding position. The cam profile is specifically shaped to complete the extraction quickly and smoothly, ensuring the preform is freed from the mandrel before any potential rotation can occur during high-speed operation.
Solution Approach 2:
The cam mechanism provides dynamic control of the mandrel extraction process, allowing the extraction speed to vary during the cycle. The cam profile creates a controlled motion sequence that accelerates and decelerates the mandrel extraction smoothly, matching the high preform running speed while maintaining precise angular positioning through the predetermined cam path.
2Device complexity
If a fixed cam is used to control mandrel extraction, then the device structure is simple, but the extraction speed is limited by the cam path slope against elastic return force
Solution Approach 1:
The cam mechanism is designed with a specifically shaped profile that creates dynamic extraction speeds. The cam profile includes sections with different slopes that control the extraction speed at different stages: a steeper section for rapid extraction when needed, and gentler sections for controlled deceleration and positioning. This dynamic cam design overcomes the limitation of fixed extraction speed while maintaining the simplicity of a mechanical cam system.
3Productivity
If the preform is heated at high speed, then production rate is improved, but the preform may be incorrectly positioned during transfer causing damage to equipment
Solution Approach 1:
The cam-controlled mandrel extraction performs the positioning-critical action in advance, before the preform is transferred to the molding station. By ensuring complete and controlled extraction at the optimal moment in the cycle, the system prevents mispositioning issues that could lead to equipment damage during high-speed operation.
Solution Approach 2:
The cam mechanism provides inherent feedback control through its mechanical geometry. The cam profile is designed to automatically adjust the extraction timing and speed based on the preform position in the cycle, ensuring that extraction is complete and controlled before transfer occurs, thereby preventing equipment damage from mispositioned preforms.
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
Enhances production speed and reliability by minimizing involuntary preform rotation and ensuring safe ejection of mispositioned preforms, thereby maintaining production continuity and reducing equipment damage.
Implementation Method 1
utilizing a linear motor and cam follower system to manage the mandrel's active and inactive positions efficiently
Implementation Method 2
A conveying device with a lifting cam section that reduces mandrel extraction time and allows for controlled ejection of incorrectly positioned preforms, utilizing a linear motor and cam follower system
Data Source
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AI summary
The invention relates to a hollow body conveying device (10) for a container manufacturing installation by preforming, the conveying device comprising: - a transport element (24) having a mandrel (38) mounted to slide vertically between an active position and an inactive position; - a cam follower (82) fixed to slide with the mandrel (38); - a first cam path (91A) along which a cam follower (82) occupies its active position; characterized in that it comprises a section (92) of lifting cam mounted to slide between a lower position in which an upstream end (94A) of its cam path (94) is level with the first cam path (91A) and an upper position in which a downstream end (94B) of its cam path (94) is level with the inactive position of the cam follower (82).