Punching Machine Idle Wheel Encoder Profile Length Detection
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Solution Overview
Problem
Conventional punching machines lack precision and speed in making ventilation holes on roller shutter and Venetian blind profiles due to slipping issues with motorized rollers, which limits hole placement accuracy to ±2-3 mm and maximum feed speed to 60 m/min.
Innovation Solution
The introduction of idle wheels with encoders to independently detect profile length, combined with independent motorized roller actuation and optical presence sensors, allows for precise hole placement and increased feed speeds by reducing the impact of roller slipping and optimizing movement speed regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motorized rollers are used to feed and extract the profile, then the profile can be transported through the punch, but roller slipping causes measurement errors of 2-3 mm in profile length detection
Solution Approach 1:
The patent introduces idle wheels as intermediary elements that contact the profile downstream of the punch. These idle wheels serve as mediators between the profile and the measurement system, providing a reliable reference point for length detection that is not affected by roller slipping upstream. The idle wheels rotate in response to profile movement and provide encoder signals that accurately reflect the true profile position.
Solution Approach 2:
The patent replaces the mechanical measurement approach (based on motorized roller rotation) with an optical/electronic measurement system using encoders on idle wheels. This substitution eliminates the mechanical coupling between the drive system and measurement system, allowing accurate length detection independent of roller grip conditions.
2Productivity
If feed speed is increased to improve productivity, then more profiles can be processed per unit time, but precision in hole placement deteriorates due to increased roller slipping
Solution Approach 1:
The patent replaces the mechanical speed-control system (relying on roller grip) with an electronic control system using encoders on idle wheels. This allows precise speed regulation and position tracking independent of mechanical slip, enabling high feed speeds while maintaining hole placement precision within ±0.3 mm.
Solution Approach 2:
The patent implements a feedback control system where encoders on the idle wheels continuously monitor the actual profile position and speed. This feedback information is used to adjust the punch operation and maintain precise hole placement even at high feed speeds, eliminating the trade-off between productivity and precision.
3Extent of automation
If encoders on motorized rollers are used to detect profile length, then the system can control hole positioning, but roller slipping renders the detected values inaccurate
Solution Approach 1:
The patent introduces idle wheels as intermediary measurement elements that are kinematically coupled to the profile movement but dynamically independent of the drive system. These idle wheels provide encoder signals that accurately reflect true profile position, serving as a reliable reference for numerical control despite roller slipping upstream.
Solution Approach 2:
Instead of measuring profile length by tracking the rotation of drive rollers (which slip), the patent inverts the approach by using idle wheels that are passively driven by profile movement. This inversion places the measurement function downstream where slipping does not occur, providing accurate feedback for numerical control.
Data Source
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AI summary
The present invention concerns a punching machine and a method using such a machine for making ventilation holes on roller shutter profiles, the machine comprising: - a punch 10 for making ventilation holes V on a roller shutter profile P along a direction of longitudinal extension X of the profile itself; - two pairs of motorized rollers 21, 22 and 31, 32 arranged upstream and downstream of the punch for moving the profile P in a movement direction M; and - an electronic control unit 60 of the punch adapted to control the punch in making ventilation holes according to a predefined program as a function of the length of the profile fed to the punch and/or as a function of the length of the profile extracted from the punch. The machine 1 comprises a first idle wheel 41 arranged upstream of the punch and a second idle wheel 51 arranged downstream of the punch with respect to the movement direction. Each idle wheel has its own rotation axis parallel to the rotation axis of the motorized rollers and is adapted to contact with its own circumferential profile a longitudinal portion of the profile to be dragged in rotation by the profile itself in its movement through the punch. The machine comprises for each of said idle wheels an encoder 42, 52 that is suitable to detect the angle of rotation of the respective idle wheel and is connected to the electronic control unit 60 to allow the latter to calculate the length of the profile P progressively fed to or progressively extracted from the punch as a function of the rotation angle of the idle wheel (41, 51), progressively detected over time.