Coffee Grinder Weighing Fork Layout for Precise Dose Feedback
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Solution Overview
Problem
Professional espresso coffee machines face challenges in achieving precise coffee dosing due to the sensitivity of load cells, grinding inertia, powder accumulation, motor vibrations, and accidental impacts, leading to imprecision and decalibration in existing grinder-doser apparatuses, especially in grind-by-time systems.
Innovation Solution
An electronic grinder-doser apparatus with a multi-cycle, feedback-type weighing system using a load cell positioned between the machine body and a shaped base, integrating the centering fork, which performs double weighings during and after dispensing, and automatic calibration through specific algorithms to compensate for residual amounts and vibrations, ensuring precise dosing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a load cell is integrated into the supporting fork of the filter-holding bowl to enable real-time weighing during dispensing, then dosing precision is improved, but the system becomes vulnerable to accidental impacts and decalibration
Solution Approach 1:
The patent divides the weighing function from the supporting fork structure. The load cell is integrated into the machine body base rather than the fork, separating the measurement function from the mechanical support function. This segmentation protects the load cell from impacts while maintaining weighing capability.
Solution Approach 2:
The load cell is extracted from the supporting fork and relocated to the machine body base. This extraction removes the load cell from the path of potential impacts during bowl hooking and release, while still enabling weight detection through the base structure.
2Stability of the object's composition
If the filter-holding bowl is hooked to the machine body for stable positioning, then dispensing stability is improved, but the load cell is exposed to accidental impacts causing decalibration
Solution Approach 1:
The patent segments the hooking mechanism from the weighing mechanism. The bowl hooks to the fork which is attached to the base, while the load cell is integrated into the base separately. This allows stable bowl positioning without direct connection between the bowl and load cell, preventing impact transmission.
Solution Approach 2:
The base structure acts as an intermediary between the load cell and the bowl hooking mechanism. It transmits the weight of the bowl and coffee to the load cell while isolating the load cell from impact forces generated during bowl attachment and detachment.
3Device complexity
If grinding time is fixed in grind-by-time systems, then device complexity is reduced, but dosing precision deteriorates due to variable coffee dispensing rates
Solution Approach 1:
The patent implements feedback control where the load cell continuously monitors the weight of dispensed coffee and provides real-time information to the control system. This feedback enables dynamic adjustment of grinding duration to achieve precise dosing while accounting for variations in coffee flow rate and dispensing conditions.
Solution Approach 2:
The system transitions from static fixed-time control to dynamic weight-based control. The grinding duration is no longer fixed but is dynamically determined by real-time weight measurements, allowing the system to adapt to varying coffee dispensing rates and maintain dosing precision.
4Measurement precision
If a highly sensitive load cell is used to detect small weight variations, then dosing precision is improved, but the system becomes more susceptible to vibrations and impacts from motor operation
Solution Approach 1:
The load cell is extracted from the vibrating components and relocated to the stationary base. This separation removes the sensitive measurement element from the source of vibrations generated by the motor and grinding mechanism, allowing high sensitivity operation without interference from mechanical vibrations.
Solution Approach 2:
The base structure serves as a vibration-isolating intermediary between the load cell and the moving components. It transmits only the static weight signal to the load cell while filtering out high-frequency vibrations from motor operation and grinding processes.
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 provides precise and autonomous calibration during operation, reducing operator intervention and maintaining consistent dispensing accuracy, addressing the issues of sensitivity, inertia, and vibrations, while protecting the load cell from impacts and ensuring reliable detection and stability.
Implementation Method 1
said cell being interposed between said machine body and a shaped base, which integrates the centering fork of said bowl, making said hooking independent
Implementation Method 2
the sensitivity of load cells, grinding inertia, powder accumulation, motor vibrations
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
Electronic grinder-doser apparatus (10) of the type with weight control or "grind-by-weight", intended to grind and precisely dose coffee in beans dispensing the ground product in a filter-holding bowl (200) for espresso coffee; the invention implements a dose compensated weighing system, of the multi-cycle and feedback type at every cycle, carried out by a device (116) with a load cell (103) and specific execution programs (117). Said cell is interposed between the machine body (105) and a base (102) shaped in such a way as to integrate the centering fork (113) of the bowl, making the hooking independent; said specific programs (117) execute each grinding and dispensing cycle with a double weighing and automatic calibration, according to an Algorithm A comprising 4 steps (AF1-AF4) and a Filtering Algorithm B. The apparatus (10) is suitable for professional daily use and helps the operator, by automatically calibrating during use.