Safety Switch Locking Pin With Controlled Plastic Deformation
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Solution Overview
Problem
Existing safety switches for industrial machines and plants are prone to pin breakage or deformation under excessive stress, leading to unsafe access conditions due to the pin descending and failing to detect such conditions, and are often complex and costly.
Innovation Solution
A safety switch with a locking pin that plastically deforms without breaking when subjected to excessive stress, featuring a locking element with controlled deformation to prevent the pin from moving to the unlocking position, ensuring it remains wedged and preventing unsafe access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking pin is used in the locking/unlocking mechanism, then the actuator device can be retained on the switching device, but the pin may break or deform under excessive stress leading to unsafe access conditions
Solution Approach 1:
The patent changes the material parameter of the locking pin by specifying it be made of plastic material instead of traditional metallic materials. This parameter change allows the pin to deform plastically under excessive stress rather than breaking, transforming the failure mode from catastrophic breakage to controlled deformation that still maintains locking function.
Solution Approach 2:
The patent converts the harmful effect of excessive stress that would normally cause pin breakage into a beneficial controlled deformation. The plastic material allows the pin to absorb excessive energy through deformation, converting the harmful stress into a protective mechanism that prevents complete failure while maintaining the locking function.
2Reliability
If a complex locking mechanism with multiple referral mechanisms is used to prevent pin breakage, then pin breakage is avoided, but the device complexity and cost increase
Solution Approach 1:
The patent extracts the complex referral mechanisms from the locking system and replaces them with a simple plastic locking pin. By removing the unnecessary complex components and retaining only the essential locking function with a simplified plastic pin design, the patent achieves breakage prevention without the associated complexity and cost.
Solution Approach 2:
The patent employs a simple, inexpensive plastic locking pin that can be easily replaced if needed, rather than using complex expensive mechanisms. The plastic pin serves its locking function reliably and can be disposed of or replaced at low cost, eliminating the need for complex protective mechanisms.
3Reliability
If the locking pin is designed to prevent breakage, then reliability improves, but the pin may still descend in broken conditions causing false operation
Solution Approach 1:
The patent incorporates a sensor that provides feedback on the actual position of the locking pin. This feedback mechanism allows the control system to detect whether the pin is in the correct locked position or has descended to an incorrect position, enabling the system to distinguish between legitimate opening conditions and false conditions caused by pin deformation or breakage.
Solution Approach 2:
The patent performs a preliminary verification of the locking pin position through sensor detection before allowing machine operation. By checking the pin position in advance, the system prevents false operation that could occur if the pin had descended to an incorrect position, ensuring that opening conditions are only recognized when properly authorized.
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 prevents unsafe access by maintaining the pin in a locked position even under excessive stress, ensuring safe operation by preventing the machine from restarting in unsafe conditions.
Implementation Method 1
a locking element with controlled deformation mechanically connected to said locking pin and sized to plastically deform without breaking following the application on said locking pin, through said operating pin, of a first deformation stress higher than a predetermined threshold value
Data Source
AI summary
A safety switch for controlling the access to industrial machines or plants comprises a switching device (2) housing switching means and an actuator device (3) having an operating pin (8) to interact with the switching means upon the opening/closing of the access, a locking/unlocking mechanism (14) housed in the switching device (2) and provided with a locking pin (15) movable between a locking position and an unlocking position of the access, an operating pin (8) associated with the actuator device (3) to interact with the locking pin (15) to hold the actuator device (3) fastened to said switching device (2), which, in turn, houses a locking element with controlled deformation, mechanically connected to the locking pin (15) and sized to deform plastically upon the application on the locking pin (15) of a deformation stress higher than a predetermined threshold value.