Pivotable Gripper Arms for Reliable Preform Handling
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Solution Overview
Problem
Existing blow molding devices face challenges in reliably and gently handling preforms at high speeds without causing mechanical damage, as current tongs do not meet the requirements for efficient and trouble-free handling of preforms and blow-molded bottles.
Innovation Solution
The device features tong-like transport elements with pivotably coupled arms, a central element, and springs that automatically close and hold preforms without external forces, allowing for easy positioning and release, and a compact design with a step-shaped central element and adapted contours for secure handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional tongs are used for handling preforms, then the handling can be performed with simple structure, but the preforms cannot be handled reliably at high speeds without mechanical damage
Solution Approach 1:
The patent applies dynamics by making the tong arms movable and adjustable through a cam mechanism. The tong arms can pivot relative to the tong carrier, allowing dynamic adaptation to different preform positions and orientations during high-speed handling. This dynamic capability enables reliable handling at high speeds while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent introduces a cam mechanism as an intermediary element that mediates between the drive system and the tong arms. The cam converts rotational motion into the desired pivoting motion of the tong arms, providing smooth and controlled movement without requiring complex direct actuation mechanisms. This intermediary approach simplifies the overall system while improving handling reliability.
2Ease of operation
If external forces are applied to open and close tongs, then precise positioning can be achieved, but the device complexity and actuation requirements increase
Solution Approach 1:
The patent applies self-service through the cam mechanism that automatically positions the tong arms during the rotation cycle. The cam profile is designed to automatically open and close the tongs at the appropriate times without requiring external positioning forces. The tong arms follow the cam contour, achieving precise positioning automatically as part of the rotational motion, thereby simplifying operation while maintaining control precision.
3Productivity
If high conveying rates are used, then productivity increases, but mechanical damage to preforms during handling increases
Solution Approach 1:
The dynamic pivoting capability of the tong arms allows them to adapt to the preform's position and orientation during high-speed conveying. This dynamic adjustment enables gentle engagement and disengagement of the preforms, reducing mechanical damage while maintaining high conveying rates. The smooth motion controlled by the cam mechanism prevents sudden impacts or jerks that could damage the 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
This solution enables reliable and gentle handling of preforms and blow-molded containers at high speeds, minimizing mechanical damage and requiring minimal external actuation, with a stable and efficient mechanism for both closing and opening the transport element.
Implementation Method 1
each of the tong arms (45, 46) is resiliently braced by at least one spring (56, 57) relative to the central element (49)
Data Source
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AI summary
The apparatus serves for blow moulding containers. Preforms of a thermoplastic material are heated in the region of a heating zone and subsequently transferred to a blow moulding device. The blow moulding device is provided with at least one blow moulding station for transforming the preforms into the containers. Provided for handling the preforms is a gripper-like transporting element (41) with two gripper arms (45, 46), which are arranged pivotably in relation to a gripper carrier (42). Each of the gripper arms can be pivoted by means of at least one lever and is coupled with a central element (49). The central element is arranged at least partly between the gripper arms. Each of the gripper arms is resiliently clamped with respect to the central element by at least one spring (56, 57).