Pivoting Pencil Sharpener Entry for Different Pencil Diameters

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Solution Overview

Problem

Conventional pencil sharpeners face difficulties in sharpening pencils with different outer diameters, leading to issues such as pencil breakage, operational complexity, and increased size and cost.

Innovation Solution

A pencil sharpener with a pivotally connected cap and blade assembly that allows for sharpening pencils of varying diameters by adjusting the inner diameter of the pencil entry, featuring a cap that pivots between positions to accommodate different pencil sizes and includes elastic holding units to stabilize thinner pencils.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple blade assemblies are combined to sharpen pencils with different outer diameters, then adaptability is improved, but device complexity and volume increase

Engineering Contradiction:
Improvecapability to sharpen pencils with different outer diametersVSAvoidstructure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The cap is designed to pivot between a first position (covering the first pencil entry) and a second position (exposing the first pencil entry). This dynamic configuration allows a single blade assembly to serve multiple functions: when the cap is in the first position, it creates a smaller inner diameter for thin pencils; when in the second position, the larger first pencil entry accommodates thick pencils. This resolves the contradiction by providing adaptability through positional change rather than through multiple static blade assemblies.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If adjusting sheaths are designed to tight fit the pencil entry, then adaptability is improved, but ease of operation deteriorates due to installation and detachment difficulties

Engineering Contradiction:
Improveadjustability of inner diameterVSAvoidinstallation and detachment convenience
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The cap is pivotally connected to the base, allowing it to rotate freely between positions. This dynamic connection eliminates the tight-fit problem of adjustable sheaths. The cap can be easily pivoted to the first or second position without requiring forceful installation or detachment, while still providing the adaptability of adjusting the effective inner diameter for different pencil sizes.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If the cap pivots to the first position to accommodate thinner pencils, then adaptability is improved, but device complexity increases due to additional components

Engineering Contradiction:
Improvecapability to sharpen thinner pencilsVSAvoidnumber of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The cap serves multiple functions: it acts as a protective cover for the blade assembly, a guide for thin pencils (creating a smaller inner diameter when positioned first), and a structural component that can pivot to expose the larger first pencil entry for thick pencils. This multi-functionality provides adaptability for different pencil sizes without adding separate adjusting sheaths or components, thereby avoiding increased device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4674637A1Pencil sharpener
Publication Date: 2026.01.07 SDI CORPORATION
  • EP4674637A1 patent drawingFigure 1
  • EP4674637A1 patent drawingFigure 2
  • EP4674637A1 patent drawingFigure 3

AI summary

A pencil sharpener has a base (10), a blade assembly (20) mounted to the base (10), and a cap (30) pivotally connected to the base (10). The cap (31) has a second pencil entry (31) smaller than the first pencil entry (21) of the blade assembly (20). When the cap (30) is at a first position, the second pencil entry (31) is located above the first pencil entry (21) along an axis (C), such that a pencil (P) is insertable into the blade assembly (20) through the second pencil entry (31) and the first pencil entry (21) in order. When the cap (30) is at a second position, the cap (30) is withdrawn from a space above the blade assembly (20), such that another pencil (P') is insertable into the blade assembly (20) through the first pencil entry (21) along the axis (C).