Reciprocating Saw Motor-Spindle Layout for Compact Ergonomics

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Solution Overview

Problem

Existing machine tools with reciprocating output spindles and drive motors are often bulky and obstructive, requiring significant space and obstructing the view of clippings due to their angular arrangements, which complicates ergonomic design and compactness.

Innovation Solution

A machine tool design where the drive motor and output spindle are coupled via a gear, with the drive motor positioned next to the output spindle, intersecting at an angle α (preferably 17°) to achieve a compact and balanced form that enhances the stroke of the output spindle and allows for a more ergonomic handle alignment, reducing obstruction and improving usability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the drive motor and output spindle are arranged at right angles or in star shape configuration, then the machine tool can be driven, but the machine tool requires a relatively large amount of space and the drive motor obstructs the view of clippings

Engineering Contradiction:
Improvespace occupationVSAvoidobstruction of view
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent changes the spatial arrangement from traditional right-angle or star-shaped configurations to an aligned longitudinal arrangement where the drive motor and output spindle are positioned one behind the other along the same axis. This dimensional reorganization eliminates the protruding motor configuration that obstructed the view and reduced compactness.

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

2Volume of moving object

If the drive motor is positioned in the handle to achieve compactness, then the machine tool becomes more compact, but the handle must have a minimum size to accommodate the drive motor

Engineering Contradiction:
ImprovecompactnessVSAvoidhandle size requirement
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent merges the drive motor and output spindle into a compact aligned configuration where both components share the same longitudinal space. This combining approach allows the motor to be positioned within the handle assembly without requiring excessive handle size, achieving both compactness and ergonomic handling.

Inventive Principle:
Principle #5Merging (Combining)

3Volume of moving object

If the longitudinal axes of the motor and spindle are aligned or parallel, then the machine tool achieves compact design, but the handle alignment becomes restrictive

Engineering Contradiction:
Improvecompact designVSAvoidhandle alignment flexibility
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The patent employs asymmetric angular positioning of the output spindle relative to the handle axis, creating an optimized ergonomic angle that differs from traditional aligned configurations. This asymmetric arrangement provides both compact design and improved operational comfort by allowing the handle to be positioned at an optimal angle for user control.

Inventive Principle:
Principle #4Asymmetry

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 results in a compact, well-balanced machine tool that minimizes obstruction of clippings, provides a greater stroke of the output spindle, and enhances ergonomic handling, making the tool more efficient and user-friendly.

Implementation Method 1

a drive motor (28), which are coupled to one another via a gear (30)

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

coupled to one another via a gear (30)

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentEP3581309B1Machine tool with reciprocating output shaft
Publication Date: 2022.10.19 ROBERT BOSCH GMBH
  • EP3581309B1 patent drawingFigure 1~2
  • EP3581309B1 patent drawingFigure 3a
  • EP3581309B1 patent drawingFigure 3b

AI summary

A machine tool (1), in particular a reciprocating saw, is proposed, comprising a reciprocating output spindle (24) and a drive motor (28) coupled to each other via a gearbox (30), wherein a longitudinal side (38) of the output spindle (24) and a longitudinal side (40) of the drive motor (28) run side by side, so that the drive motor (28) is arranged next to the output spindle (24). This results in a very compact design.