Optical Gap Protection for Bending Machines With Moving Light Barriers
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Solution Overview
Problem
Existing protective devices for bending machines do not adequately ensure operator safety during the reduction of the operating gap, as they fail to effectively interrupt the approach process of the upper tool when an operator's hand or fingers are at risk of being crushed.
Innovation Solution
A protective device with an optical source and receiver, controlled by a safety-oriented light barrier controller, which uses a linear drive system and redundant position-measuring systems to ensure the optical beam covers the entire operating gap and interrupts the machine's movement if an obstruction is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple light barrier is used to monitor the operating gap, then the device complexity is reduced, but the reliability of safety protection deteriorates because the approach process is not effectively interrupted when the upper tool is at risk of contacting the operator's hand or fingers
Solution Approach 1:
The protective device is segmented into multiple independent functional components: optical source, optical receiver, linear drive system with motor, position-measuring system with encoder, and control unit. Each component performs a specific function, and the segmentation allows for modular design and improved reliability through distributed functionality, resolving the contradiction between reliability and complexity.
Solution Approach 2:
The linear drive system proactively moves the optical source and receiver into position before the upper tool reaches the dangerous zone. The position-measuring system continuously monitors the tool position in advance, and the control unit preemptively interrupts the approach process when potential contact is detected, preventing harmful contact before it occurs.
2Reliability
If the optical source and receiver are made adjustable via linear drive system, then the optical beam can cover the entire operating gap improving safety coverage, but the device complexity increases due to additional drive and position-measuring systems
Solution Approach 1:
The linear drive system serves multiple functions: it positions the optical source and receiver to cover the entire operating gap, maintains optimal detection alignment, and enables adaptive adjustment based on tool position. This multi-functionality improves safety coverage while avoiding the need for separate adjustment mechanisms, partially mitigating the complexity increase.
Solution Approach 2:
The position-measuring system with encoder provides continuous feedback on the location of the upper tool and the position of optical components. The control unit uses this feedback to automatically adjust the optical source and receiver positions, ensuring complete coverage of the operating gap without requiring manual intervention or complex mechanical adjustment mechanisms.
3Measurement precision
If redundant processing of sensor signals is implemented in the light barrier controller, then the measurement precision and reliability are improved, but the processing time and device complexity increase
Solution Approach 1:
The system replaces complex mechanical safety monitoring with an optical measurement system that uses light barriers and redundant sensor signal processing. The electronic/optical redundancy provides high measurement precision without the mechanical complexity and time delays associated with mechanical backup systems, effectively resolving the contradiction between precision and time loss.
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 solution effectively safeguards the operating gap by ensuring the optical beam covers the entire gap and interrupts the machine's movement if an obstruction is detected, thereby preventing operator injury.
Implementation Method 1
an optical source (52) for the provision of an optical beam (56) in the operating gap (15) and an optical receiver (54) arranged opposite the optical source (52) to receive the optical beam (56) from the optical source (52)
Data Source
AI summary
Protective device for safeguarding an operating gap of a bending machine, having an optical source to provide an optical beam along the operating gap, having an optical receiver arranged opposite the optical source to receive the optical beam, a safety-oriented light barrier controller that performs redundant processing of sensor signals provided from the optical receiver, and a linear drive system for attachment to the bending machine and for providing linear movements for the optical source and the optical receiver relative to an upper tool of the bending machine. The linear drive including a linear drive and a safety-oriented position measuring system with a position sensor and a position checking system, in which a safety-oriented linear drive controller is connected to the linear drive system and processes sensor signals from the position sensor and signals from the position checking system and provides a closed loop control for the linear drive.