Tool and drive device for a motor driven kitchen appliance

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Solution Overview

Problem

Existing motor-driven kitchen appliances lack effective safety mechanisms to prevent injuries from tools still in operation during improper use, such as opening the lid while the appliance is running.

Innovation Solution

A tool with a drive shaft and coupling mechanism featuring a sleeve that can be displaced by a restoring force to separate from the counter-coupling, ensuring the tool is not driven when the lid is opened, thereby preventing operator contact with rotating cutting instruments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a braking mechanism is used to stop the tool when the lid is removed, then safety is improved, but the device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the safety function from a complex braking mechanism and implements it through a simple coupling disengagement system. When the lid is removed, the coupling between the drive shaft and counter-coupling automatically disengages, taking the tool out of the drive path and preventing it from rotating, thereby stopping it without requiring a separate braking mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using a braking mechanism to stop a rotating tool (active safety), the invention inverts the approach by using a coupling disengagement mechanism that prevents the tool from being driven in the first place when the lid is removed (passive safety). The spring element pushes the coupling away from the counter-coupling, ensuring the tool cannot be activated unless the lid is properly in place.

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

2Reliability

If a spring element is used to push the casing away from the counter-coupling, then safety is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
ImprovesafetyVSAvoidmanufacturing precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The spring element is pre-loaded to automatically push the casing away from the counter-coupling when the lid is removed, performing the safety action in advance before any potential hazard can occur. This preliminary action ensures that even with normal manufacturing tolerances, the coupling will reliably disengage without requiring high-precision manufacturing.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention uses a spring element to change the positional parameter of the casing relative to the counter-coupling. The spring provides a force that overcomes normal manufacturing variations and ensures consistent disengagement distance, making the safety mechanism robust against manufacturing precision limitations.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the coupling is designed to automatically disengage when the lid is removed, then safety is improved, but the ease of operation decreases

Engineering Contradiction:
ImprovesafetyVSAvoidease of operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The coupling mechanism is designed to be self-actuating through the spring element. When the lid is removed, the spring automatically pushes the casing away from the counter-coupling, causing the coupling to disengage without requiring any additional action from the operator. This self-service mechanism maintains ease of operation while ensuring safety.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The coupling system incorporates dynamic elements (spring, movable casing) that automatically respond to the lid's position. The spring provides a restoring force that dynamically adjusts the coupling engagement based on whether the lid is attached or removed, making the safety function automatic and intuitive without complicating operation.

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

This solution effectively prevents injuries by ensuring the tool is not operational when the lid is removed, enhancing safety during improper use and providing a simple, intuitive mechanism for production and handling.

Implementation Method 1

a restoring means, and the casing (8) is displaceable in a coupling direction relative to the coupling (7) by the restoring force of the restoring means (9)

Methodology Applied
Scientific EffectElastic restoring force: Elasticity

Data Source

PatentEP2677910B1Tool and drive device for a motor driven kitchen appliance
Publication Date: 2019.05.08 BSH HAUSGERATE GMBH
  • EP2677910B1 patent drawingFigure 1
  • EP2677910B1 patent drawingFigure 2
  • EP2677910B1 patent drawingFigure 3

AI summary

The invention relates to a tool (2) for a motor driven kitchen appliance (1) on which an instrument (3) for processing food products is disposed, said tool comprising a drive shaft (6) on the end of which a coupling (7) is formed, and a sleeve (8) disposed partially or completely enclosing the drive shaft (6), wherein the tool (2) comprises a return means (9) and the sleeve (8) can be slid relative to the coupling (7) in a coupling direction of the coupling (7) by the return force of the return means (9). An embodiment of the tool (2) according to the invention in a motor driven kitchen appliance (1) is shown in Fig. 1. The invention further relates to a drive device for driving a tool (2) for a motor driven kitchen appliance (1) comprising a counter-coupling, wherein the counter-coupling comprises an ejecting element and a return means, and the ejecting element can be slid relative to the counter-coupling in a counter-coupling direction of the counter-coupling by the return force of the return means. The tool (2) and the drive device are intended to provide a safety mechanism that is simple to implement in production and simple and intuitive to operate by an operator and that is not necessarily based on a braking device. Injuries that could be caused by a tool that is still driven can be prevented by means of the invention.