Power Tool Gear Selector with Slide-Rotate Speed Shifting

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Solution Overview

Problem

Existing power tools with shifting devices for gearboxes have complex structures, making it difficult for users to easily switch between different reduction ratios for varying output rotation speeds.

Innovation Solution

A power tool design featuring a shifting device with a first and second shifting element, an operation member, and a connecting member that allows for easy switching between different transmission states, using a combination of sliding and rotational mechanisms to change gear positions without altering the position of other elements, simplifying the structure and user operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a shifting device is added to enable switching between different reduction ratios, then the power tool can have different output rotation speeds, but the structure becomes complex

Engineering Contradiction:
Improveoutput rotation speedsVSAvoidshifting device structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The shifting device is segmented into two independent shifting elements (first and second shifting elements), each controlling a specific gear position. This segmentation allows each element to handle a subset of gear switching tasks, reducing the complexity of individual elements while collectively providing multiple reduction ratio options for different output rotation speeds.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The operation member is designed with multi-functionality, serving both as a selector for the first shifting element (controlling first gear position) and as a driver for the second shifting element (controlling second gear position) through different movement modes (sliding vs. rotating). This universal design consolidates multiple shifting controls into a single component, reducing overall device complexity while maintaining versatility in gear selection.

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

2Adaptability or versatility

If a complex shifting device is used to switch between reduction ratios, then different transmission states are achievable, but ease of operation deteriorates

Engineering Contradiction:
Improvetransmission statesVSAvoidshifting operation
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The operation member employs dynamic control mechanisms where different movement types (sliding along the central axis vs. rotating about the central axis) trigger different shifting actions. This dynamic design allows the user to easily select between different gear positions by simply changing the movement mode, making the shifting operation intuitive and easy to perform while achieving multiple transmission states.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The operation member acts as an intermediary between the user and the two shifting elements. Through this intermediary, the user can control both the first and second shifting elements using a single component with different movement modes, simplifying the user interface and making the shifting operation easier while still achieving multiple transmission states.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3546132B1Power tool
Publication Date: 2021.02.17 NANJING CHERVON IND
  • EP3546132B1 patent drawingFigure 1
  • EP3546132B1 patent drawingFigure 2
  • EP3546132B1 patent drawingFigure 3

AI summary

A power tool (100), including an output member (13), a motor (12), a housing (11), a transmission device (20), and a shifting device (30). The shifting device includes a first shifting element (33), a second shifting element (34), an operation member (31), and a connecting member (32). The first shifting element is capable of switching between a first position and a second position, and the second shifting element is capable of switching between a third position and a fourth position. When sliding relative to the housing, the operation member drives the first shifting element to switch between the first position and the second position, and a position of the second shifting element remains unchanged. When the operation member rotates relative to the housing, the connecting member drives the second shifting element to switch between the third position and the fourth position, and a position of the first shifting element remains unchanged.