High-precision externally-adjustable coffee grinder

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Solution Overview

Problem

Existing electric coffee grinders face issues with low precision in adjusting coffee powder coarseness due to limited adjusting ranges and complex operation mechanisms, leading to instability and user confusion.

Innovation Solution

A high-precision externally-adjustable coffee grinder with a coarseness adjusting structure that includes an external adjusting ring and internal driving ring, utilizing a reduction gear mechanism to enhance precision and simplify the adjustment process, while avoiding motor movement to maintain stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a one-turn adjusting ring is used to adjust the grinding disc gap, then the adjustment operation is simple and convenient, but the adjusting precision is poor due to limited rotation angle range

Engineering Contradiction:
Improveadjustment operation convenienceVSAvoidadjusting precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The adjusting ring is divided into multiple independent adjusting pieces (first adjusting piece, second adjusting piece, third adjusting piece) with different functions. The first adjusting piece controls coarse adjustment (0-2mm range), the second adjusting piece controls fine adjustment (0.2-0.5mm range), and the third adjusting piece controls precise adjustment (0.05-0.1mm range). This segmentation allows each piece to have optimal rotation angle and precision for its specific adjustment range, resolving the contradiction between operational simplicity and adjusting precision.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If a multi-turn adjusting piece is used to improve adjusting precision, then the adjusting precision is improved, but the operation becomes complex and users get confused about the number of turns and rotation scales

Engineering Contradiction:
Improveadjusting precisionVSAvoidoperation complexity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The adjusting mechanism is segmented into three independent adjusting pieces, each with its own dedicated rotation scale and adjustment range. Users only need to focus on one adjusting piece and its corresponding scale at a time, eliminating the confusion of tracking multiple turns across a single multi-turn mechanism. Each adjusting piece operates within a limited rotation angle (less than 360 degrees), making it easy to read and control.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each adjusting piece is designed with localized adjustment functionality and dedicated scale markings. The first adjusting piece has scales for 0-2mm adjustment, the second has scales for 0.2-0.5mm adjustment, and the third has scales for 0.05-0.1mm adjustment. This local quality approach ensures that each component has optimized characteristics for its specific function, improving overall precision without increasing operational complexity.

Inventive Principle:
Principle #3Local quality

3Device complexity

If the adjusting knob is arranged at a lower end of the movable cutterhead (downward-adjusting), then the structure is compact, but the adjusting operation is inconvenient

Engineering Contradiction:
Improvestructure compactnessVSAvoidadjusting operation convenience
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

Instead of placing the adjusting knob at the lower end of the movable cutterhead (downward-adjusting), the invention inverts the adjustment direction by placing the adjusting knob at the upper end of the main body (upward-adjusting). This inversion makes the adjusting knob more accessible and easier to operate, while the adjusting mechanism still achieves compact structure through the threaded connection between the adjusting knob and mounting shaft.

Inventive Principle:
Principle #13The other way round (Inversion)

4Ease of operation

If the adjusting knob drives the motor to move up and down (making motor mounting rack movable), then the adjusting operation is convenient, but the motor movement causes fatigue and gradual displacement of the adjusting structure, affecting stability

Engineering Contradiction:
Improveadjusting operation convenienceVSAvoidadjusting structure stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention extracts the motor from the moving part of the adjusting mechanism and fixes it to the stationary main body. The adjusting knob drives a lifting rod through a threaded connection, which directly adjusts the position of the movable cutterhead without moving the motor. This separation ensures that the motor remains stationary, eliminating fatigue and gradual displacement, while the adjusting operation remains convenient through the upward-adjusting design.

Inventive Principle:
Principle #2Taking out (Extraction)

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 improved precision and ease of use by allowing multi-stage adjustments with clear scale indications, ensuring stable and uniform grinding coarseness without motor displacement, thus enhancing user experience and market competitiveness.

Implementation Method 1

a transmission gear, the internal toothed ring of the external adjusting ring being engaged with an external toothed ring of the internal driving ring through the transmission gear

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 2

the adjusting knob is in threaded connection with a mounting shaft

Methodology Applied
Scientific EffectScrew mechanism: Screw

Data Source

PatentEP4623773A1High-precision externally-adjustable coffee grinder
Publication Date: 2025.10.01 TANZHEXINGJI (SHANGHAI) NETWORK TECH CO LTD
  • EP4623773A1 patent drawingFigure 1
  • EP4623773A1 patent drawingFigure 2
  • EP4623773A1 patent drawingFigure 3

AI summary

Disclosed in the present invention is a high-precision externally-adjustable coffee grinder, including a main housing, a lifting rod, a grinding assembly and a coarseness adjusting structure, where the coarseness adjusting structure includes an external adjusting ring, an internal driving ring, a transmission gear; the external adjusting ring is sleeved and rotates relative to the main housing; the external adjusting ring includes an internal toothed ring; the internal driving ring includes an external toothed ring; the external adjusting ring is engaged with the internal driving ring through the transmission gear; and the external adjusting ring drives the internal driving ring to rotate to drive the lifting rod to adjust a grinding disc gap. The number of turns of the internal driving toothed ring is increased, so that the adjusting precision of the adjusting structure is greatly improved, the advantages of convenient adjustment of the externally-adjustable coffee grinder and clear scale indication of a one-turn coffee grinder are retained, and the problem of low precision of the one-turn adjusting coffee grinder in the prior art is solved.