Transparent Hand Guard for Precision Axe Striking

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Solution Overview

Problem

Existing hand-held percussion tools with long handles often result in inaccurate strikes due to small angle changes during use, leading to the risk of missing the target or bouncing off, potentially causing injury.

Innovation Solution

A hand guard designed as a curved, transparent plate that occupies the entire grip length, positioned immediately adjacent to the tool head, providing precise guidance and visibility while allowing the handle to be grasped directly next to the head, with optional sighting devices and guide ribs for enhanced accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the handle is designed with usual length and grasped at a distance from the tool head, then the tool provides sufficient leverage and momentum for striking, but small angle changes during execution result in inaccurate strikes and increased risk of injury

Engineering Contradiction:
ImprovemomentumVSAvoidaiming accuracy
Core Design Contradiction:
ForceVSMeasurement precision

Solution Approach 1:

The handle is divided into two functional segments: a short grip section (5 cm) for precise hand control and a longer extension section for generating momentum. This segmentation allows the user to maintain accurate aim through the short grip area while still achieving sufficient strike distance and momentum through the extended portion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A hand guard (7) is introduced as an intermediary component between the hand and the tool head. This hand guard provides a stable gripping surface that maintains consistent hand-positioning and angle control during the striking motion, preventing aim deviation while allowing full momentum transfer.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Length of moving object

If the handle is made longer to increase striking distance, then more momentum can be generated, but the control precision and accuracy of the strike deteriorates

Engineering Contradiction:
Improvehandle lengthVSAvoidstrike accuracy
Core Design Contradiction:
Length of moving objectVSMeasurement precision

Solution Approach 1:

The handle is segmented into a short controlled section (5 cm) for precise aim and a longer extension section for momentum generation. This allows the tool to achieve both accurate strike placement and sufficient striking distance without compromising either function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the handle are designed with different characteristics: the grip area (5 cm) is optimized for precision control with a specific diameter and texture, while the extension area is designed for momentum generation. This local differentiation allows each section to fulfill its specific function optimally.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If a hand guard is added to protect the hand from accidentally hitting the workpiece, then user safety is improved, but the device complexity increases

Engineering Contradiction:
Improvehand injury riskVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The hand guard is designed as a thin, curved plate (2-5 mm thick) that provides adequate protection while maintaining minimal structural complexity. The thin-walled design reduces the overall complexity compared to a solid protective shield, while still effectively preventing hand contact with the workpiece during striking.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The hand guard is formed as a curved plate that follows the natural contour of the hand. This curved design provides effective hand protection while using minimal material and maintaining simple construction. The curvature allows the hand guard to conform to the hand shape, providing protection without adding significant structural complexity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP2114625B1Striking tool
Publication Date: 2017.05.10 HIMMELBERGER ZEUGHAMMERWERK LEONHARD MULLER & SOHNE
  • EP2114625B1 patent drawingFigure 1~2
  • EP2114625B1 patent drawingFigure 3~4
  • EP2114625B1 patent drawingFigure 5~6

AI summary

The invention relates to a hand tool, e.g. in the form of an ax or a hatchet, having a head (1) and a grip (5). A hand protector (7) is arranged between the head (1) and the grip (5) and is at least partially transparent. Because the grip (5) is arranged directly next to the head (1) of the ax, the ax can be aimed better, such that a user has an increased likelihood to hit the workpiece that he wishes to modify (split) exactly where he wants to hit it. The grip (5), and likewise the hand protector (7) can be made of different materials, wherein wood, plastic, or metal are considered primarily. In order to allow a fixing with the ax according to the invention, the head (1) of the ax can have a cutting edge (3) which has an area which is designed to be thin with respect to the rest of the head (1).