Machine Safety Light Curtain with Time-Slot Object Classification
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Solution Overview
Problem
Existing safety devices for machines, such as light curtains, often provide insufficient protection for operators due to inability to differentiate between human body parts and machine elements, leading to unnecessary false shutdowns and disruptions.
Innovation Solution
A safety device using transceiver units that emit and receive light beams in specific time slots to differentiate between reflecting and non-reflecting objects, allowing for precise classification and triggering of emergency shutdowns only when necessary, thereby reducing false shutdowns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional light curtains are used to detect intrusions, then safety protection is provided, but false shutdowns occur frequently due to inability to differentiate between safety-critical intrusions and desired operations
Solution Approach 1:
The patent applies parameter changes by utilizing different time slots for emitting light beams from first and second transceiver units. This temporal parameter differentiation enables the system to distinguish between reflecting objects (detected in specific time slot patterns) and non-reflecting objects, thereby reducing false shutdowns while maintaining safety protection.
Solution Approach 2:
The system implements feedback through the evaluation unit that continuously monitors light beam reflections and determines object characteristics. Based on this feedback, the control unit selectively triggers emergency shutdowns only when reflecting objects are detected, avoiding unnecessary disruptions from non-reflecting objects while maintaining reliable safety protection.
2Reliability
If light curtains trigger emergency shutdowns for all intrusions, then high safety requirements are met, but unnecessary false shutdowns occur involving considerable disruptions and product damages
Solution Approach 1:
The patent uses parameter changes by implementing time-slot-based light beam emission and detection. The evaluation unit analyzes the temporal patterns of reflected light beams to differentiate between reflecting objects (which indicate safety-critical intrusions) and non-reflecting objects, thereby meeting high safety requirements while eliminating false shutdowns caused by non-reflecting objects.
Solution Approach 2:
The system applies local quality by treating different types of objects differently based on their reflection properties. Reflecting objects trigger emergency shutdowns to ensure safety, while non-reflecting objects are allowed to pass without triggering shutdowns, thereby preventing false shutdowns while maintaining high safety standards for actual hazards.
3Measurement precision
If reflecting elements are used for triggering, then recognizing of exclusively reflecting parts is enabled, but non-reflecting components cannot be recognized and permanent self-monitoring is not possible
Solution Approach 1:
The patent implements universality by designing a dual-transceiver system that can detect both reflecting and non-reflecting objects through different time slot patterns. The first transceiver unit emits light beams in first time slots and the second transceiver unit emits light beams in second time slots, enabling the system to universally detect all object types while maintaining precise recognition of reflecting objects through the evaluation unit's analysis of reflection patterns.
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 safety device effectively differentiates between reflecting and non-reflecting objects, reducing the risk of unnecessary shutdowns and ensuring safer operation of machines by accurately identifying potential hazards.
Implementation Method 1
The safety device comprises a first transceiver unit for emitting a first light beam in a first time slot. The first transceiver unit is employed for receiving a second light beam in the first time slot. The safety device further comprises a second transceiver unit, which is arranged for emitting the second light beam in the second time slot that is different from the first one.
Data Source
AI summary
The invention is directed to a safety device for a machine that includes a first transceiver unit for emitting a first light beam in a first time slot and for receiving a second light beam. The safety device includes a second transceiver unit arranged for emitting the second light beam in a second time slot that is different from the first one. The safety device also includes an evaluation unit for determining a reflecting object between the first transceiver unit and the second transceiver unit, only if the first light beam is received by the first transceiver unit in the first time slot or the second light beam is received by the second transceiver unit in the second time slot. Additionally, a non-reflecting object may be detected, if by neither of the two transceiver units in both time slots one of the two light beams is received.