Twist-Action Retractable Pen Barrel Cap Threaded Engagement
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Solution Overview
Problem
Existing retractable writing instruments require additional components for the cartridge retraction/extension mechanism, increasing complexity and costs.
Innovation Solution
A retractable pen design with a twisting mechanism where the cartridge is integrated into the cap and barrel components, utilizing threaded engagement to allow for extension and retraction without additional parts, with rings preventing cap separation from the barrel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If additional components are used for the cartridge retraction/extension mechanism, then the mechanism can be implemented, but the device complexity and component costs increase
Solution Approach 1:
The patent merges the retraction mechanism functionality directly into the barrel structure by forming a spiral groove within the barrel wall. This eliminates the need for separate retraction components (such as separate springs, cam mechanisms, or additional guide structures) that would otherwise be required, thereby reducing device complexity while maintaining the retraction function through the integrated spiral groove geometry
Solution Approach 2:
The barrel serves multiple functions: it contains the ink cartridge, provides the retraction mechanism through its spiral groove, guides the cartridge movement, and structures the cap attachment. This multi-functionality reduces the overall component count by making the barrel a universal element that combines several previously separate functions into one component
2Ease of operation
If the cap and barrel are freely rotating, then the cartridge can be retracted and extended, but the cap may separate from the barrel
Solution Approach 1:
The patent introduces an intermediary engagement mechanism between the cap and barrel that allows controlled movement. The cap includes engagement features (such as protrusions or threads) that interact with corresponding features in the barrel, creating a mediated connection that permits the necessary rotation for cartridge retraction/extension while preventing complete separation through the intermediary engagement structures
3Ease of manufacture
If a two-piece construction is used, then component costs and assembly are reduced, but the structural integrity may be compromised
Solution Approach 1:
The patent divides the writing instrument into two separate pieces: the barrel assembly (containing the cartridge and retraction mechanism) and the cap assembly. This segmentation simplifies manufacturing and assembly by allowing each component to be produced independently and then joined through simple attachment methods, reducing overall manufacturing complexity while maintaining adequate connection strength through the designed interface
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
This design simplifies the construction and assembly process, reducing component costs while maintaining functionality, and ensures the cap remains attached to the barrel in both extended and retracted positions.
Implementation Method 1
first and second threads are in threaded engagement with each other, the cartridge is received in and extends through the through channel, and the barrel and the cap are rotatingly movable relative to each other via the threaded engagement
Data Source
AI summary
A retractable pen includes a cartridge partially received in a recess of a cap such that a first end of the cartridge is fixedly attached to the cap. An elongate barrel includes first and second open ends and a through channel fluidly interconnecting the first and second open ends. A portion of the barrel is snugly and threadedly received in the recess such that the cartridge is received in and extends through the through channel, and the barrel and the cap are rotatingly movable relative to each other via the threaded engagement between an extended position in which the second end of the cartridge extends through and out of the second open end of the barrel, and a retracted position in which the second end of the cartridge is disposed within the barrel.