Handheld Power Tool Gearbox With Linked Shift Transmission Elements

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Solution Overview

Problem

Hand-held machine tools with complex actuation devices are required to individually control multiple switching gear elements for gearbox switching, leading to a cumbersome operating concept.

Innovation Solution

A gearbox design where the switching gear element of the first gear wheel arrangement acts as a switching actuator for the second gear wheel arrangement, allowing for simplified operation by adjusting only the first gear wheel arrangement to switch both, eliminating the need for complex actuation of the second gear wheel arrangement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If multiple switching gear elements are individually controlled by complex actuation devices, then gear switching functionality is achieved, but operating complexity increases

Engineering Contradiction:
Improveease of gear switchingVSAvoidcomplexity of actuation device
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines multiple switching gear elements (first switching gear element and second switching gear element) into a single integrated switching mechanism. The actuation device simultaneously actuates both gear elements through a unified motion path, eliminating the need for separate control mechanisms and reducing overall device complexity while maintaining full gear switching functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single actuation device is designed to perform multiple functions: it simultaneously controls the first switching gear element for engaging/disengaging the first gear arrangement and the second switching gear element for engaging/disengaging the second gear arrangement. This multi-functional approach reduces the number of components and simplifies the operating concept.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple switching gear elements are individually actuated, then complete gear control is achieved, but the number of components increases

Engineering Contradiction:
Improvegear switching capabilityVSAvoidnumber of gear elements
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent merges the control of multiple gear elements into a single actuation system. The actuation device incorporates both the first switching gear element and the second switching gear element in a integrated manner, allowing both to be actuated through a single operational input, thereby reducing the effective number of independently controlled components.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If complex actuation devices are used for gear switching, then precise gear engagement is achieved, but the housing structure becomes more complex

Engineering Contradiction:
Improvegear engagement precisionVSAvoidhousing structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the switching gear elements directly into the housing structure in a unified arrangement. The first switching gear element and second switching gear element are positioned and coordinated within the housing such that a single actuation motion simultaneously achieves precise engagement for both gear arrangements, eliminating the need for complex separate actuation mechanisms and simplifying the overall housing design.

Inventive Principle:
Principle #5Merging (Combining)

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

Simplifies the operation of hand-held machine tools by reducing the complexity of the actuation device, allowing for easier switching between gear positions without the need for additional housing openings or complex control mechanisms.

Implementation Method 1

the switching transmission element of the first gear arrangement forms a switching actuator for the second gear arrangement, which is switchable between a first setting position and at least one second setting position, in which a mobility of the switching transmission element of the second gear arrangement differs

Methodology Applied
Scientific EffectMechanical engagement: Mechanical Force

Implementation Method 2

in both gear wheel arrangements, the at least one gear wheel can roll on the switching transmission element of the gear wheel arrangement

Methodology Applied
Scientific EffectRolling contact: Roller

Data Source

PatentEP3676053B1Hand-held power tool
Publication Date: 2024.01.10 FESTOOL GMBH
  • EP3676053B1 patent drawingFigure 1
  • EP3676053B1 patent drawingFigure 2
  • EP3676053B1 patent drawingFigure 3

AI summary

The invention relates to a hand-held power tool comprising a drive motor (17), a transmission (40) arranged on a transmission holding structure (44A), particularly a transmission housing (44), and a tool-receiving element (29), a motor output (27) of the drive motor (17) being coupled to a transmission drive of the transmission in a rotating manner, and a transmission output (42) of the transmission, which can be rotated about an axis of rotation, being coupled to the tool-receiving element (29) in a rotating manner, the transmission being shiftable between at least two gearshift positions (S1, S2, S3, S4) in which speed ratios between the transmission drive and the transmission output (42) are different from each other, and the transmission comprising a first gear wheel arrangement (104) and at least one second gear wheel arrangement (105), which each comprise at least one gear wheel and a shift transmission element. In the two gear wheel arrangements (104, 105), the at least one gear wheel can roll on the shift transmission element and/or the shift transmission element can roll on the at least one gear wheel, and each shift transmission element is mounted such that it can move between at least two actuating positions and/or can be moved between a stationary position and a mobile position in relation to the transmission holding structure (44A), for controlling the gearshift positions (S1, S2, S3, S4) of the transmission on the transmission holding structure (44A). According to the invention, in order to shift the transmission between at least two of the gearshift positions (S1, S2, S3, S4), the shift transmission element (102) of the first gear wheel arrangement (104, 105) forms a gearshifting part for the second gear wheel arrangement (105), which can be shifted between a first actuating position and at least one second actuating position, in which a mobility of the shift transmission element (103) of the second gear wheel arrangement (105) is different in terms of the transmission holding structure (44A) and/or the gearshifting part is disengaged and engaged with the at least one gear wheel (105A) of the second gear wheel arrangement.