Retractable Pen and Eraser Helical Cam Assembly for Easy Refilling
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Solution Overview
Problem
Traditional rotating retractable writing instruments with a retractable writing tip and eraser have complex mechanisms and are often not refillable.
Innovation Solution
A writing instrument with a simpler mechanism that allows both the writing tip and eraser to axially move, featuring a first and second helical cam propelling mechanism that can be actuated together, enabling easy refilling and replacement of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional rotating retractable writing instrument mechanism is used, then the writing tip and eraser can be retracted, but the mechanism becomes complex and refilling becomes difficult
Solution Approach 1:
The writing instrument is divided into separable components: a reusable body containing the cam mechanism and refillable cartridges containing the writing tip and eraser. This segmentation allows the complex mechanism to be simplified by separating it from the consumable parts, enabling easy refilling while maintaining the retractability function through the cam-driven rotation mechanism.
2Reliability
If a traditional rotating retractable writing instrument mechanism is used, then the writing tip and eraser can be retracted, but refilling becomes not easily possible
Solution Approach 1:
The writing instrument is divided into separable components: a reusable body containing the cam mechanism and refillable cartridges containing the writing tip and eraser. This segmentation allows the complex mechanism to be simplified by separating it from the consumable parts, enabling easy refilling while maintaining the retractability function through the cam-driven rotation mechanism.
Solution Approach 2:
The writing tip and eraser are nested within the refillable cartridge, which itself is inserted into the main body. The eraser can be disposed around the writing tip, creating a compact nested structure that simplifies the refilling process while maintaining both functions in a space-efficient manner.
3Volume of moving object
If the eraser is disposed around the writing tip, then a compact design is achieved, but the mechanism requires precise coordination of multiple components
Solution Approach 1:
The eraser and writing tip are merged into a single refillable cartridge assembly, with the eraser disposed around the writing tip. This combining reduces the overall number of separate components and simplifies the refilling process, while the cam mechanism coordinates the retraction of both elements through a single rotational motion.
Solution Approach 2:
The refillable cartridge serves multiple functions: it holds the writing tip, accommodates the eraser, and provides a unified refilling interface. The cam mechanism provides universal control over both the writing tip and eraser retraction through a single rotational action, reducing the need for separate control mechanisms.
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
Enables easy refilling and replacement of the writing tip and eraser, while maintaining a compact and efficient design with a simpler mechanism.
Implementation Method 1
a first helical cam propelling mechanism (18) configured to move the writing tip (14) between a retracted position and a protruded position. The writing instrument comprises a second helical cam propelling mechanism (20) configured to move the eraser (16) between a retracted position and a protruded position
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
A writing instrument (10) extending along an axis (X) and comprising a writing tip (14) and an eraser (16), a first helical cam propelling mechanism (18) configured to move the writing tip (14) along the axis (X) between a retracted position and a protruded position and a second helical cam propelling mechanism (20) configured to move the eraser (16) along the axis (X) between a retracted position and a protruded position, the first helical cam propelling mechanism (18) comprising a first cam follower (18A) and a first helical cam (18B), the second helical cam propelling mechanism (20) comprising a second cam follower (20A) and a second helical cam (20B), each of the first cam follower (18A), the first helical cam (18B), the second cam follower (20A) and the second helical cam (20B) being provided on distinct elements.