Safety Sensor Reed Contact Arrangement for Cylinder Positioning
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Solution Overview
Problem
Existing safety position sensors for pneumatic or hydraulic cylinders are prone to false indications due to external magnetic fields and unintentional sensor displacement, requiring a solution that ensures accurate positioning and immunity to external influences.
Innovation Solution
A sensor system with three reed contacts, where two are parallel and one is at a greater distance, is actuated by a magnet on the piston, with shielding to prevent external magnetic interference and secure fixation using fastening tails and locking mechanisms to prevent sensor movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two reed contacts are arranged parallel and close to each other for simultaneous actuation, then the sensor can detect piston position accurately, but the sensor becomes vulnerable to external magnetic field manipulation
Solution Approach 1:
The sensor is segmented into three reed contacts with different spatial arrangements: two parallel reed contacts (first and second) for position detection and one third reed contact positioned at a distance for security verification. This segmentation allows the system to distinguish between legitimate piston-induced magnetic fields and external interference fields.
Solution Approach 2:
The third reed contact acts as an intermediary security element that verifies the legitimacy of sensor actuation. By positioning it at a distance from the parallel reed contacts, it serves as a mediator to detect whether the magnetic field originates from the piston (which would actuate all three) or from external sources (which would only actuate the parallel pair).
2Ease of operation
If the sensor is made easily adjustable along the displacement axis, then installation and positioning are simplified, but the sensor becomes susceptible to unintentional displacement
Solution Approach 1:
The sensor mounting system transitions from a static fixed position to a dynamic adjustment mechanism. The sensor can be freely positioned along the displacement axis during installation to achieve optimal alignment with the piston magnet, then locked into place to prevent unintended movement during operation. This dynamic approach combines ease of adjustment with operational stability.
Solution Approach 2:
The sensor position is adjusted and optimized before final locking during the installation phase. This preliminary action allows the sensor to be positioned exactly where needed for accurate detection, and then the locking mechanism prevents any subsequent unintentional displacement during cylinder operation.
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
Ensures accurate detection of the piston's safe position by preventing external magnetic field manipulation and secure sensor positioning, enhancing safety and reliability in monitoring the piston's position within the cylinder.
Implementation Method 1
A sensor for monitoring a part that is translationally displaceable relative to the sensor with regard to its position on the displacement axis and can be actuated by means of a magnet arranged on the displaceable part
Implementation Method 2
three reed contacts arranged in parallel, of which a first and a second reed contact are arranged in one plane
Data Source
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AI summary
The invention relates to a sensor (11) for monitoring the position of a translationally displaceable part (45) relative to the sensor on the displacement axis. Such a part is, for example, a piston (45) in a cylinder (43) equipped with the sensor (11). The sensor (11) can be actuated by means of a magnet (19) arranged on the displaceable part, the magnet being oriented with respect to its north and south poles in the direction of displacement. The sensor has three parallel reed contacts (15, 16, 17), of which a first (15) and a second (16) reed contact are arranged next to each other in the same plane and with their longitudinal axes parallel, so that they can be actuated practically simultaneously by the magnetic field (51) of the magnet (19) arranged on the displaceable part (45). The third reed contact (17) is arranged at a distance from the plane of the first and second reed contacts (15, 16).This sensor (11) is mounted facing the actuating magnet (19) with the first two reed contacts (15, 16) facing the actuating magnet. This arrangement has the advantage that an external magnetic field will always also actuate the third reed contact (17) if it is able to actuate the first two reed contacts. The sensor (11) then indicates an error message or an unsafe position, but never a safe position of the movable part (45).