Handheld Grinding Machine Spring-Loaded Machining Head

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Solution Overview

Problem

Handheld grinding machines face difficulties in positioning the machining head relative to wall surfaces due to the length of the handle bar, making it inconvenient for precise sanding work.

Innovation Solution

A positioning spring arrangement is used to load the machining head into a defined base position, allowing for flexible positioning relative to the handle element, with the spring arrangement comprising leg springs, rubber buffers, or helical springs, enabling easy alignment and movement along the workpiece surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a long handle bar is used in the handheld grinding machine, then the operator can reach distant wall surfaces, but the positioning of the machining head relative to the wall surface becomes difficult and inconvenient

Engineering Contradiction:
Improvehandle bar lengthVSAvoidpositioning ease
Core Design Contradiction:
Length of moving objectVSEase of operation

Solution Approach 1:

The patent applies the dynamics principle by introducing a positioning spring arrangement that allows the machining head to move dynamically between a base position and adjusted positions. The spring-loaded mechanism enables the head to be flexibly positioned along the longitudinal axis while maintaining a defined resting position, resolving the contradiction between reachability and positioning precision.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If the machining head is rigidly fixed to the handle element, then the structure is simple and stable, but the operator cannot easily adjust the position of the machining head relative to the wall surface

Engineering Contradiction:
Improvestructural stabilityVSAvoidpositioning flexibility
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The positioning spring arrangement transforms the rigid connection into a dynamic, adjustable connection. The machining head can be easily moved along the longitudinal axis of the handle element and held at various positions by the spring force, providing both stability when positioned and flexibility for adjustment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The positioning spring arrangement acts as an intermediary element between the machining head and the handle element. This spring mechanism mediates the connection, allowing relative movement while maintaining controlled positioning, thus enabling both structural stability and positioning flexibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the positioning spring arrangement is integrated with the line arrangement, then the device complexity is reduced, but the positioning function may interfere with the suction hoses or other lines

Engineering Contradiction:
Improvestructural complexityVSAvoidinterference with suction hoses
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent applies segmentation by separating the positioning spring arrangement from the line arrangement (suction hoses). The positioning mechanism is implemented independently through support arms and springs that do not interfere with the suction hoses, allowing both functions to operate independently without mutual interference.

Inventive Principle:
Principle #1Segmentation

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 allows for comfortable and precise positioning of the machining head along the workpiece surface, improving the ease of sanding operations by providing a defined but flexible base position, reducing the need for external forces and enhancing maneuverability.

Implementation Method 1

A handheld power tool (10) in the form of a grinding machine comprises a machining head (11) and a handle element (12), wherein the machining head (11) is spring-loaded by a positioning spring arrangement (70) in a base position relative to the handle element (12)

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3246127B1Manually operated machine tool with a positioning spring assembly
Publication Date: 2021.12.15 FESTOOL GMBH
  • EP3246127B1 patent drawingFigure 1~2
  • EP3246127B1 patent drawingFigure 3~15
  • EP3246127B1 patent drawingFigure 6~7

AI summary

The invention relates to a hand-held power tool with a handle element (12), in particular a rod-shaped handle element, for gripping by an operator and a machining head (11) movably mounted on the handle element (12) via a joint arrangement (13), which has a tool holder (19) for holding a machining tool (20) and which can be driven by an electric drive motor (100) of the hand-held power tool (10), wherein a cable arrangement (41) for transmitting electrical and/or mechanical energy and/or for conducting a suction flow (S) is provided between the handle element (12) and the machining head (11). In the hand-held power tool, it is provided that the machining head (11) is biased into a predetermined base position relative to the handle element (12) by a positioning spring arrangement (70) that is separate from the cable arrangement (41).