Cam Gear Actuating Device for Garden Tillage Switch Protection

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Solution Overview

Problem

Existing garden tillage machines lack a compact and user-friendly operating mechanism for actuating switches, which can lead to overpressing and potential damage, especially with long movement distances of the actuating elements.

Innovation Solution

A compact operating device design featuring a rotatably mounted actuating element with a cam gear unit that translates long movements into short switch activation distances, incorporating a spring element for overload prevention and a blocking unit for two-hand operation to prevent incorrect activation, allowing for secure and damage-free operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a long movement distance of the actuating element is used, then the operation comfort is improved, but the switch may be overpressed and damaged

Engineering Contradiction:
Improveoperation comfortVSAvoidswitch durability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A cam gear unit is introduced as an intermediary mechanism between the actuating element and the switch. The cam gear unit includes a cam gear element with a cam track that converts the long rotational movement of the actuating element into a short linear displacement of the switch actuating element, thereby protecting the switch from overpressing while maintaining operational comfort

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The cam gear unit changes the movement parameters by converting a long rotational movement path into a short linear displacement. The cam track geometry is designed to transform the actuating element's rotation into a controlled, limited linear motion that actuates the switch without excessive force or displacement

Inventive Principle:
Principle #35Parameter changes

2Volume of moving object

If a compact design is implemented, then the device size is reduced, but the switching mechanism may lack sufficient actuation distance

Engineering Contradiction:
Improvedevice sizeVSAvoidactuation distance
Core Design Contradiction:
Volume of moving objectVSLength of moving object

Solution Approach 1:

The cam gear element employs a curved cam track instead of a straight line. This curved path allows the mechanism to pack a long effective actuation path into a compact space, enabling the actuating element to rotate through a sufficient angle while keeping the overall device size small

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The cam gear unit transforms the actuation from a linear dimension to a rotational dimension. The actuating element rotates around an axis perpendicular to the switch actuation direction, allowing long movement distances to be achieved through rotation while maintaining compact linear dimensions

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of operation

If a single-hand operation is used, then the ease of operation is improved, but incorrect activation may occur

Engineering Contradiction:
Improveease of operationVSAvoidactivation accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A blocking unit is implemented that prevents switch actuation unless a specific two-hand operation sequence is performed. The blocking element initially blocks the cam gear element from actuating the switch, and only after the operator performs the correct sequence (actuating the first operating element, then the second) does the blocking element move to allow switch activation, thereby preventing incorrect or accidental activation

Inventive Principle:
Principle #9Preliminary anti-action

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 enables comfortable, secure, and damage-free operation of garden tillage machines by efficiently actuating switches with reduced risk of overpressing, maintaining a compact design and enhancing user safety through two-hand operation.

Implementation Method 1

the cam gear unit comprises at least one cam gear element (24a), which is arranged on the actuating element (20a)

Methodology Applied
Scientific EffectCam mechanism: Cam

Implementation Method 2

the actuating unit (18a) comprises at least one spring element (34a) for at least partial compensation of an actuating force that can be generated by a movement of the actuating element (20a)

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP2875709B1Operating device of a gardening machine
Publication Date: 2018.05.23 ROBERT BOSCH GMBH
  • EP2875709B1 patent drawingFigure 1
  • EP2875709B1 patent drawingFigure 2~3
  • EP2875709B1 patent drawingFigure 4~5

AI summary

The invention relates to an operating device for a gardening machine, in particular an electrically operated gardening machine, comprising at least one switching unit (14a; 14b) which includes at least one electrical switch (16a; 16b), and at least one actuating unit (18a; 18b) which includes at least one movably mounted actuating element (20a; 20b) for generating an actuating force to actuate the switch (16a; 16b). It is proposed that the actuating unit (18a; 18b) comprises at least one cam drive unit (22a; 22b) by means of which a movement of the actuating element (20a; 20b) can be used to actuate the switch (16a; 16b).