Cone Insert Pencil Sharpener With Finger-Safe Blade Lock

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Solution Overview

Problem

Existing sharpening devices for pencils, particularly those with a diameter up to 18 mm, pose a risk of finger injury due to the sharp blade, and existing safety mechanisms are not effective in preventing such injuries, especially when used by children.

Innovation Solution

A sharpening device with a cone-shaped insert body that moves between non-use and use positions, locked by safety mechanisms that prevent finger contact with the blade, requiring pencil insertion to unlock, and featuring a protective space to ensure safe handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the sharpener channel is made large enough to accommodate pencils up to 18 mm in diameter, then the device can handle larger pencils, but the risk of finger injury increases as fingers can also be inserted into the channel

Engineering Contradiction:
Improvepencil diameter rangeVSAvoidfinger injury risk
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The sharpener channel is divided into two distinct sections: a first section with a larger cross-sectional area for receiving the pencil, and a second section with a smaller cross-sectional area that contains the sharpening unit. This segmentation allows the channel to accommodate large pencils while physically restricting finger access to the dangerous sharpening area.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A closure element is introduced as an intermediary component that can be inserted into the second section of the sharpener channel. This closure element acts as a barrier between the user's finger and the sharpening unit, allowing safe operation while preventing direct contact with the cutting edge.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If closure elements are added to close the insertion opening when not in use, then finger protection is improved, but the device complexity increases

Engineering Contradiction:
Improvefinger injury preventionVSAvoidclosure mechanism
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The closure element is designed to be movable rather than fixed, allowing it to be dynamically positioned. It can be inserted into the second section to protect against finger injury when the sharpener is not in use, and removed when pencil sharpening is needed. This dynamic design provides safety without requiring complex locking mechanisms.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4650186A1Sharpening device
Publication Date: 2025.11.19 A W FABER CASTELL GMBH & CO
  • EP4650186A1 patent drawingFigure 1~2
  • EP4650186A1 patent drawingFigure 3
  • EP4650186A1 patent drawingFigure 4~5

AI summary

The invention relates to a sharpening device (10) to sharpen pencils comprising - a frame (12) forming an interior space and providing a receiving section (16) therein, - a sharpening unit (14) that is attached to a wall of the frame (12) in such a way that a cutting edge of the sharpening unit (14) is directed towards the receiving section (16), - a cone-shaped insert body (18) that is arranged within the receiving section (16), wherein the cone-shaped insert body (18) provides a receiving space (20) to receive a front section of a pencil (100) through an insertion opening (22) provided at a rear end of the cone-shaped insert body (18), and wherein the cone-shaped insert body (18) is movable within the receiving section (16) between a non-use position and a use position along a longitudinal axis (L)of the sharpening device, - safety means (24, 30) to releasably lock the cone-shaped insert body (18) within the receiving section (16) in the non-use position, wherein the cone-shaped insert body (18) is fixed against movement along the longitudinal axis (L) in the receiving section (16) and the receiving space (20) of the cone-shaped insert body (18) is located at a distance (T1) to the sharpening unit (14).