Coin Sensor Arrangement for Miscounting Prevention
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Solution Overview
Problem
Coin processing machines miscount larger denomination coins due to metal contaminants overlaying sensors, particularly the upstream sensor associated with half-dollar coins, leading to incorrect identification of smaller coins as half-dollars.
Innovation Solution
An additional sensor is placed in the path of the pivoting guide finger's swing arc, generating a signal only when a largest-diameter coin passes, ensuring accurate counting by the controller, and the pivoting finger's motion helps prevent and clear contaminants from reaching the sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sensors are placed upstream to detect coins early in the processing stream, then coin detection speed and processing throughput are improved, but sensor reliability deteriorates due to metal contaminants overlaying the sensors
Solution Approach 1:
The patent extracts the sensing function from the fixed upstream location and relocates it to the moving alignment finger. This allows the sensor to be positioned in a contaminated environment when needed for detection, then moved away to prevent contaminant buildup, effectively separating the detection function from the vulnerable fixed sensor location
Solution Approach 2:
The patent makes the sensor position dynamic by mounting it on the movable alignment finger. The sensor transitions from a static upstream position to a dynamic position that moves with the finger, allowing it to approach coins for detection then retreat to avoid contaminant accumulation, resolving the contradiction between early detection and contaminant exposure
2Measurement precision
If the alignment finger is positioned close to the sensor to engage larger-diameter coins, then coin alignment and detection accuracy are improved, but the finger becomes more susceptible to being contaminated by metal particles
Solution Approach 1:
The alignment finger with its mounted sensor transitions from a static to a dynamic component. It moves close to the sensor path during coin engagement for accurate detection, then retreats to a retracted position where it is less exposed to contaminants, allowing the system to achieve measurement precision without permanent exposure to harmful factors
Solution Approach 2:
The spring mechanism performs preliminary action by automatically returning the alignment finger to its retracted position after coin engagement. This preliminary retraction prevents contaminant accumulation before it can affect subsequent detection operations, maintaining measurement precision over time
Data Source
AI summary
A coin sensor arrangement to sense the different diameters of coins in a singulated stream of coins moving along a coin path includes a movable member that is displaced from a first position to a second position by passage of the largest-diameter coins moving along the coin path. When the member reaches the second position, the member actuates the coin sensor arrangement to signal the presence of the coin. Actuation of the coin sensor arrangement can take place spaced away from the coin stream where possible contaminants that might affect sensing are less likely to be present.