Worm-Drive Spindle Adjustment for Coffee Grinder Torque and Tolerance

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Solution Overview

Problem

Conventional adjustment devices for grinders in fully automatic coffee machines require tight manufacturing tolerances and high-cost stepper motors, limiting cost-effectiveness and torque transmission, and often produce noise during operation.

Innovation Solution

A self-locking worm drive with a spindle drive mechanism that allows for adjustable torque transmission, enabling precise grinding adjustments with large dimensional tolerances and reduced noise by using a compact worm drive and spindle drive system, which can be driven by a smaller electric motor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional adjustment devices with stepper motors are used, then precise setting of the degree of grinding is achieved, but manufacturing costs increase and torque transmission is limited

Engineering Contradiction:
Improveprecision of grinding degree settingVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive stepper motors with a purely mechanical adjustment device consisting of an adjusting ring with gear teeth that mesh with a pinion gear on the adjustment spindle. This mechanical substitution eliminates the need for costly electronic motors while maintaining precise adjustment capability through gear engagement, directly resolving the contradiction between precision and manufacturing cost.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs standard mechanical components (adjusting ring, pinion gear, adjustment spindle) that are inexpensive and readily available, replacing specialized expensive stepper motors. These conventional mechanical parts can be manufactured at lower cost while achieving the required functional precision for grinding adjustment.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Measurement precision

If conventional adjustment devices with stepper motors are used, then precise setting of the degree of grinding is achieved, but torque transmission capability is reduced

Engineering Contradiction:
Improveprecision of grinding degree settingVSAvoidtorque transmission
Core Design Contradiction:
Measurement precisionVSForce

Solution Approach 1:

The patent replaces the stepper motor-driven mechanism with a direct mechanical gear system where the adjusting ring's gear teeth mesh with the pinion gear. This mechanical substitution provides superior torque transmission through direct gear engagement, eliminating the torque limitations of stepper motors while maintaining precise positioning through the gear ratio.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs curved gear teeth on the adjusting ring that mesh with the pinion gear, creating a continuous contact interface that distributes load and maximizes torque transmission. The curved geometry of the gear engagement provides mechanical advantage and efficient force transfer throughout the adjustment range.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Productivity

If adjustment is performed during grinder operation, then continuous operation is maintained, but noise from grinding masks adjustment noises

Engineering Contradiction:
Improvecontinuous operationVSAvoidnoise masking
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent enables dynamic adjustment during grinder operation through its mechanically coupled adjusting ring and pinion gear system. The user can continuously adjust the grinding degree by rotating the adjusting ring while the grinder operates, with the mechanical linkage providing real-time adjustment without interruption to the grinding process.

Inventive Principle:
Principle #15Dynamics

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 allows for cost-effective production with larger tolerances, high torque transmission, and silent operation during grinding adjustments, enhancing the precision and efficiency of the grinding process in fully automatic coffee machines.

Implementation Method 1

an adjustment device for adjusting the degree of grinding of a grinder with a driven or drivable worm drive (3)

Methodology Applied
Scientific EffectWorm drive: Worm Drive

Implementation Method 2

The worm drive of the adjustment device can also be implemented as self-locking

Methodology Applied
Scientific EffectSelf-locking mechanism: Friction

Data Source

PatentEP3718446B1Adjusting device for adjusting the grinding efficiency of a grinding mill
Publication Date: 2022.11.02 BSH HAUSGERATE GMBH
  • EP3718446B1 patent drawingFigure 1~2
  • EP3718446B1 patent drawingFigure 3~4

AI summary

The invention relates to an adjustment device (1) for adjusting the grind setting of a grinder (2), in particular for a fully automatic coffee machine, which comprises a driven or driveable worm drive (3). Furthermore, the adjustment device (1) comprises a spindle drive (4) which is drive-connected to the worm drive (3). The spindle drive (4) can be operatively connected to an adjusting element (5) of the grinder (2) to adjust it.