Safety Switch Lock-Out Shielding Signal Transmission
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Solution Overview
Problem
Existing safety switches with lock-out devices for industrial machines and plants lack reliability and modularity, often allowing unintended interactions between switching and operating units, and fail to maintain protection in applications requiring continuous closure, such as refrigerators, due to incomplete shielding and non-modular designs.
Innovation Solution
A safety switch with a lock-out device featuring a movable guard that interposes a shielding element between communication elements to prevent signal passage, ensuring interaction prevention in both active and inactive positions, and allowing modular use on various door types without requiring different mounting configurations, using electronic communication elements and locking mechanisms accessible only in the active position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lock-out device with a movable guard is used to obstruct the slot, then safety is improved by preventing actuator interaction, but the device complexity increases due to additional components and mounting requirements
Solution Approach 1:
The lock-out device is segmented into separate functional components: a movable guard for obstructing the slot, a support structure for mounting, and locking means. This segmentation allows each component to be optimized independently and simplifies the overall assembly and installation process.
Solution Approach 2:
The movable guard acts as an intermediary element between the actuator and the switching unit. It provides a physical barrier that prevents direct interaction between the actuator and the slot, thereby enhancing safety without requiring complex interlocking mechanisms.
2Reliability
If holes are provided on the support for locking means to prevent unauthorized removal, then reliability is improved, but ease of operation deteriorates as the operator cannot easily remove the lock-out device
Solution Approach 1:
The support structure provides different local qualities: it has a first face with holes for locking means to prevent unauthorized removal, and a second face without holes that allows easy removal by authorized personnel. This local differentiation resolves the contradiction between security and ease of operation.
Solution Approach 2:
Instead of providing holes on all faces of the support (which would compromise security), the invention inverts the approach by providing holes only on the first face while leaving the second face solid. This allows the lock-out device to be securely locked from one side while being easily removable from the other side by authorized personnel.
3Reliability
If the lock-out device is designed to be locked in the safety position, then safety is improved, but adaptability deteriorates as the device cannot be removed by unauthorized persons
Solution Approach 1:
The lock-out device incorporates a movable guard that can be positioned in different states: locked in the safety position to prevent actuator interaction, or removable by authorized personnel using the locking means. This dynamic design allows the device to adapt between maintaining safety and allowing authorized access.
Solution Approach 2:
The support structure serves multiple functions: it provides mounting for the movable guard, incorporates locking holes on the first face for security, and maintains a solid second face for easy removal by authorized personnel. This multi-functionality enhances both safety and adaptability.
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 ensures safe operation in all conditions, prevents accidental reactivation, and maintains protection closed even with the lock-out device inserted, enhancing reliability and modularity for diverse applications.
Implementation Method 1
a guard (17) movable between an inactive position adapted to allow the interaction between said switching means (102) and said actuating means (105) and an active position in which this interaction is avoided
Data Source
AI summary
A safety switch with a lock-out device including a switching unit, switching elements and actuating elements. The switching elements and the actuating elements are electronic and are respectively associated with a first communication element and a second communication element adapted to remote communicating therebetween by a signal and to allow the switching elements to discriminate the presence of an operating unit close to the switching unit. The switching unit includes a movable guard having a shielding element adapted to interpose itself between the communication elements when the guard is into the active position to avoid the transmission of the signal and the closing of the switching elements.