Rotational Position Detection for Plastic Preforms
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Solution Overview
Problem
Existing systems for producing oval or asymmetrical plastic containers with screw-on closures face challenges in rotational alignment, requiring mechanical adjustments and multiple sensors, which limits machine performance and is not adjustable for different preforms.
Innovation Solution
A device using an image recording system, such as a camera, to detect the rotational position of plastic preforms relative to their longitudinal axis through spatially resolved imaging, allowing for contact-free, adjustable illumination and evaluation, enabling precise alignment without mechanical conversions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are used to detect rotational position at each processing station, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the detection function from multiple distributed sensors and consolidates it into a single image acquisition device that captures the rotational position of the preform. This single device replaces what would otherwise require multiple sensors at different processing stations, thereby reducing device complexity while maintaining measurement precision through spatially resolved imaging
Solution Approach 2:
The patent uses optical copying through imaging to detect rotational position. Instead of using physical sensors that contact or closely approach the preform at multiple stations, a single optical system creates an image copy of the preform's position, which can then be analyzed to determine rotational orientation. This eliminates the need for multiple physical sensors and their associated calibration procedures
2Manufacturing precision
If mechanical orientation devices are used to align plastic preforms, then manufacturing precision is improved, but machine performance and productivity deteriorate
Solution Approach 1:
The patent replaces mechanical orientation devices with an optical detection and control system. Instead of using mechanical cams, gears, or physical alignment mechanisms that would slow down the production line, the system uses an image acquisition device to detect rotational position and a control device to calculate and command the required rotation. This substitution of mechanical systems with optical and electronic systems maintains manufacturing precision while significantly improving machine performance and productivity
3Measurement precision
If sensors are positioned at each blowing or transport station, then measurement precision is improved, but device complexity and ease of operation worsen due to calibration requirements
Solution Approach 1:
The patent creates a universal detection system where a single image acquisition device serves all detection needs for rotational position across the entire production line. This universal device does not require separate calibration for each station like traditional sensors would. The system captures spatially resolved images that contain positional information, and a control device processes these images to determine rotational position regardless of where in the production line the measurement is taken, thereby eliminating calibration dependencies
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
Enables precise rotational alignment of plastic preforms with a single image capture, reducing the need for multiple sensors and mechanical adjustments, improving machine performance and adaptability to various preform types.
Implementation Method 1
a lighting device (4) which illuminates the plastic preform (10)
Implementation Method 2
an observation device (2) which observes the plastic preform (10) illuminated by the lighting device (4) essentially along its longitudinal direction (L) and takes an image of the plastic preform (10)
Data Source
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AI summary
The apparatus (1) for detecting a geometrical position of plastic material containers including plastic material pre-forms (10), comprises: an image-recording device (2), which records a locally resolved image of the plastic material containers, and is arranged in such a way that it observes the plastic material containers along its longitudinal direction; an illumination device (4), which illuminates a region of the plastic material containers observed by the image-recording device; and an evaluation device. The apparatus (1) for detecting a geometrical position of plastic material containers including plastic material pre-forms (10), comprises: an image-recording device (2), which records a locally resolved image of the plastic containers and is arranged in such a way that it observes the plastic containers along its longitudinal direction; an illumination device (4), which illuminates a region of the plastic containers observed by the image-recording device; an evaluation device, which, on the basis of an image recorded by the image-recording device, determines a rotary setting of the plastic containers with respect to its longitudinal direction; and a lens body (8) arranged between the illumination device and the plastic containers. The plastic containers have a base member and a thread region. The illumination device is arranged: in an annular manner with respect to the longitudinal direction of the plastic containers; between the image-recording device and the plastic containers; below the plastic containers; and in such a way that light emerging from the illumination device does not strike the image-recording device directly. The image-recording device is arranged below the plastic containers, and records an image of an illuminated support ring. The lens body is arranged between an observation device and the plastics container. The illumination device illuminates the support ring of the plastic containers. Independent claims are included for: (1) a plant for the treatment of plastic material pre-forms; and (2) a method for detecting a geometrical position of plastic material containers.