Light Curtain with Machine Sensing for Press Brake Safety
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Solution Overview
Problem
Conventional light curtains are inadequate for machines like press brakes, as they cannot effectively sense the position and speed of moving parts, leading to incomplete protection and operational inefficiencies, as the moving parts often break the light beams during normal operation.
Innovation Solution
A light curtain system with a controller connected to the machine's controller, incorporating presence detectors and machine sensors to sense and adjust the machine's operation based on the position and speed of moving parts, using programmable beam-blank-out systems to ensure safe operation and minimize interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional light curtain is used to detect operator presence, then safety protection is provided, but the part being processed frequently breaks the light beams causing unnecessary stoppages and reduced productivity
Solution Approach 1:
The light curtain system is segmented into multiple independently controllable light beams arranged in columns. This allows selective blanking of specific beams rather than the entire light curtain, enabling the part to pass through designated areas without triggering stoppages while maintaining protection in other zones.
Solution Approach 2:
Different regions of the light curtain are assigned different functional qualities through programmable blanking patterns. Certain light beams are blanked during specific machine cycles to allow part passage, while other beams remain active for safety monitoring. This local differentiation resolves the contradiction between allowing part movement and maintaining safety detection.
2Productivity
If sequentially programmable beam-blank-out systems are used to allow part movement, then productivity is improved, but portions of the machine are left unguarded creating safety risks
Solution Approach 1:
The light curtain system dynamically adjusts its blanking pattern based on the machine cycle phase. The controller receives feedback from machine sensors about the position of moveable parts and actively reconfigures which light beams are blanked at different times. This dynamic adaptation ensures that protection is maintained in zones where parts are not present while allowing operation in zones where parts are actively being processed.
Solution Approach 2:
The system incorporates machine sensors that provide feedback about the position and movement of machine parts. This feedback is used by the controller to intelligently manage the blanking pattern, ensuring that light beams are only blanked when and where the part is actually present, thereby maintaining safety coverage in other areas while enabling productive operation.
3Device complexity
If simple light curtains are used, then device complexity is minimized, but they cannot adequately protect complex multi-step operations where parts move through different positions
Solution Approach 1:
The light curtain system performs multiple functions through a single integrated device. It provides both safety monitoring and intelligent cycle management by combining presence detection with programmable blanking capabilities. The system can adapt to different machine cycles and part geometries, making it universally applicable to various press brake operations without requiring multiple separate systems.
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
The system provides comprehensive protection by allowing the machine to operate safely, reducing the risk of injury by adjusting speeds and ensuring the machine operates only when the workspace is clear, thereby enhancing both safety and productivity.
Implementation Method 1
The at least one presence detector may comprise, for example, a plurality of light emitters and a plurality of light detectors, wherein the light emitters emit beams of light toward the light detectors
Data Source
AI summary
A light curtain for use with a machine, such as a press brake. The light curtain includes a controller which is communicatingly connected to a controller of the machine, and at least one presence detector which is connected to the controller of the light curtain. The light curtain also includes at least one sensor which is configured to sense position and/or speed of movement of a moveable part of the machine, in use, the controller of the light curtain receives feedback from the at least one presence detector as well as from the at least one sensor which is configured to sense position and/or speed of movement of the moveable part of a machine. The controller of the light curtain signals the controller of the machine to operate the machine based on the feedback which is received by the light curtain. Preferably, the at least one presence detector is sequentially programmable to effectively provide blanked-out sections, and the controller of the light curtain uses the at least one sensor to detect when the moveable part of the machine is moving through the blanked-out section, and cause the machine to slow down to a safer speed.