Angle Grinder Ratchet Element Pivoting Mechanism

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Solution Overview

Problem

Existing portable machine tools, such as angle grinders, lack an efficient mechanism for the ratchet element to provide a significant lifting movement relative to the handle housing, compromising operating comfort and ease of use.

Innovation Solution

A bearing unit with a bolt-shaped bearing element and a lever gear unit, including a parallelogram lever gear unit, is integrated to enable a pivoting movement of the ratchet element, allowing a substantial lifting movement and improved operability, while also incorporating a spring element for a dead man's switch to prevent unintentional operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional bearing unit is used for the ratchet element, then the structure is simple, but the lifting movement of the ratchet element is insufficient, compromising operating comfort

Engineering Contradiction:
Improveoperating comfortVSAvoidstructure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The bearing unit is designed to enable dynamic pivoting movement of the ratchet element about an axis extending in the longitudinal direction, allowing the ratchet element to adapt its position during operation and provide a uniform lifting movement along its entire length, thereby improving operating comfort

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The bearing unit is divided into multiple bearing elements distributed along the longitudinal extension of the ratchet element, with each bearing element supporting a specific section. This segmentation allows independent movement of different sections, enabling the ratchet element to pivot and lift uniformly along its entire operating surface

Inventive Principle:
Principle #1Segmentation

2Length of moving object

If the ratchet element is made longer to improve grip, then the lifting movement distance increases, but the structural complexity and bearing requirements increase

Engineering Contradiction:
Improveratchet element lengthVSAvoidbearing unit complexity
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

Instead of providing fixed support along the entire length of the extended ratchet element, the bearing unit enables dynamic pivoting movement. This allows a longer ratchet element to maintain grip effectiveness while the bearing elements only need to support the pivoting motion, not the entire length, thus managing complexity better

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The bearing elements act as intermediaries that facilitate the pivoting movement of the ratchet element. By introducing these intermediary bearing components, the system achieves uniform lifting movement for extended ratchet elements without requiring complex support structures along the entire length

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enhances the operating comfort and ease of use by allowing a uniform lifting movement of the ratchet element over its entire operating surface, while ensuring safety through the dead man's switch mechanism.

Implementation Method 1

a spring element for a dead man's switch, which interacts with the ratchet element and is provided for the purpose of allowing a movement of the ratchet element into an initial position

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2794186B1Power tool
Publication Date: 2019.05.15 ROBERT BOSCH GMBH
  • EP2794186B1 patent drawingFigure 1
  • EP2794186B1 patent drawingFigure 2
  • EP2794186B1 patent drawingFigure 3

AI summary

The invention relates to a power tool, especially an angle grinder, comprising at least one grip housing (14a; 14b), at least one switching unit (16a; 16b), having at least one latch element (18a; 18b) arranged on the grip housing (14a; 14b), and at least one bearing unit (20a; 20b) designed to mount the latch element (18; 18b) such that it is mobile at least with respect to the grip housing (14a; 14b). According to the invention, the bearing unit (20a; 20b) is designed to guarantee, when the latch element (18a; 18b) is actuated, a stroke movement of the latch element (18a; 18b) along a trajectory of a value greater zero, starting from an end (24a; 24b) of the latch element (18a; 18b) closer to the connecting region (22a; 22b) of the grip housing (14a; 14b) in the direction of an end (26a; 26b) of the latch element (18a; 18b) away from the connecting region (22a; 22b), which end can be gripped.