Coffee Grinder Automatic Dose Control Using Load Cell Feedback
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Solution Overview
Problem
Existing coffee grinders suffer from inaccuracies in dosing due to variable time-of-flight, which is influenced by grain size and mechanical/electronic factors, leading to errors in coffee weight dispensed.
Innovation Solution
A coffee grinder with an automatic dose control system that adjusts for time-of-flight by using a load cell, tare weight, error margin, and extra-dose time to ensure precise coffee dosing, independent of grain size and grinder mechanics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the grinder is stopped in advance to account for time-of-flight, then the coffee dose accuracy is improved, but the dosing system becomes inaccurate because time-of-flight varies with grain size and mechanical/electronic factors
Solution Approach 1:
The patent implements a feedback mechanism where the load cell continuously monitors the actual coffee weight during dispensing. The control unit receives real-time weight data and compares it with the target dose, dynamically adjusting the grinder operation to compensate for time-of-flight variations. This closed-loop feedback system eliminates the need for fixed time-of-flight calculations, resolving the contradiction between early stopping and dosing accuracy.
Solution Approach 2:
The patent replaces the mechanical/time-based time-of-flight compensation method with an electronic control system. Instead of relying on predetermined stopping times that vary with grain size and mechanics, the system uses electronic sensors (load cell) and a control unit to precisely manage the dispensing process, substituting mechanical timing with electronic measurement and control.
2Loss of time
If the load cell is calibrated to a lower weight to account for time-of-flight, then the time-of-flight is compensated, but errors and inaccuracies increase because time-of-flight is not constant for all coffee types
Solution Approach 1:
The patent transitions from a static, fixed tare weight calibration to a dynamic, real-time weight monitoring system. The load cell continuously measures the actual coffee weight during dispensing, and the control unit dynamically adjusts the stopping point based on the specific dispensing characteristics of each coffee type and grinder operation, eliminating the need for predetermined tare weights.
Solution Approach 2:
The patent changes the control parameter from a fixed tare weight value to a dynamic target weight based on real-time measurements. The system monitors the actual weight accumulation rate and adjusts the stopping condition accordingly, allowing the effective compensation parameter to change based on grain size, dispensing rate, and time-of-flight variations for different coffee types.
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
Achieves accurate and reliable coffee dosing by compensating for time-of-flight variations, ensuring consistent coffee weight within a predefined error margin.
Implementation Method 1
a load cell connected to the support to weigh the ground coffee dispensed into the filter holder
Data Source
AI summary
Disclosed is a coffee grinder having an automatic coffee dose control system that provides for comparing a difference between an ideal weight set by a user and an actual weight measured by a load cell with an error; if the difference between the ideal weight and the actual weight is greater than the error, an extra-dose of coffee powder is dispensed.