Independent Photocell Alignment for Box Paper Sheets
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Solution Overview
Problem
The existing methods for pointing sheets of paper in the construction of paper or cardboard boxes suffer from errors due to the misalignment of the center of rotation of the pointing machine with respect to the photocells, leading to increased inaccuracies as the sheet dimensions grow, affecting production quality.
Innovation Solution
The method involves independently movable width-search photocells that compensate for the error in the center of rotation by adjusting their position during the pointing process, using a combination of waiting and movement steps to align accurately, and storing sheet positions to create a history for pre-alignment, allowing for the use of various sensors like photocells, cameras, or other edge detection systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the standard pointing algorithms with parallel advancement of photocells are used, then the pointing process is simplified, but alignment precision deteriorates due to the different centre of rotation between the structure and photocells
Solution Approach 1:
The system divides the photocell array into multiple independent segments that can move and rotate independently relative to each other. Each photocell segment is positioned at a different radius from the rotation center, allowing them to compensate for the rotational mismatch error individually, thus resolving the contradiction between simple operation and high precision.
Solution Approach 2:
The photocell structure transitions from a static rigid array to a dynamic system where individual photocells can adjust their positions and orientations. The photocells are mounted on movable supports that allow independent rotation and translation, enabling real-time compensation for alignment errors during the pointing process.
2Device complexity
If the centre of rotation of the pointing machine structure is not aligned with the photocells, then the system structure is simpler, but alignment accuracy deteriorates as sheet dimensions increase
Solution Approach 1:
An intermediate mechanical structure is introduced between the rotation center and the photocells. This intermediate structure acts as a mediator that transforms the rotational motion into compensated positional adjustments, allowing the photocells to maintain accurate alignment with the sheet edges even when the overall system rotation center does not coincide with the photocell positions.
3Manufacturing precision
If independent movement of photocells is implemented to compensate for rotation errors, then alignment accuracy improves, but device complexity increases
Solution Approach 1:
The system merges the rotational adjustment function with the positional adjustment function into a unified mechanism. By combining radial and tangential movement capabilities in a single integrated structure, the system achieves complex error compensation without proportionally increasing the number of independent actuators, thus balancing precision improvement with acceptable complexity.
Data Source
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AI summary
Method for aligning sheets of paper (F), comprising a first width- search sensor (17), a second width-search sensor (16), said first and second sensors being mounted longitudinally staggered on a supporting structure (S) provided with transverse and longitudinal advancement means, and a rotation motion relative to the sheet, comprising the following steps: a) simultaneous transverse advancement of the first and second sensors, b) stop of the first sensor once a first point of a longitudinal edge of the sheet is reached, c) initiation of a advancement and retraction cycle of the first sensor between an upstream position before the edge and a downstream position after the edge of the sheet, d) initiation of a continuous checking step if the second sensor has also reached the edge of the sheet, where, during said checking step, if the second sensor has not reached the edge, continue said advancement of the second sensor and said advance and retraction cycle of the first sensor, when the second sensor has also reached the edge, retraction and immediate stop before the edge of the second sensor, waiting for the first sensor to move immediately before the edge of the sheet due to said advance and retraction cycle, and also stop of the first sensor immediately before the edge of the sheet.