Retractable Pen Tip Stability via Interference Fit and Deformable Member
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Solution Overview
Problem
Current ball pens experience tip inclination due to clearance between the ink cartridge and the barrel, leading to undesired handwriting strokes as the tip sways during writing.
Innovation Solution
A retractable pen design featuring a switching device with a limiting member, shifting member, resetting member, and deformable member ensures the ink cartridge tip is immovably pressed against the lead-out opening, preventing swaying by compressing and deforming to maintain contact without inclining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the bottom opening of the barrel has a size slightly larger than the diameter of the ink cartridge to allow the tip to project, then the tip can be extended from the barrel, but a clearance is formed between the ink cartridge and the bottom opening causing the tip to incline and sway during writing
Solution Approach 1:
The patent applies preliminary anti-action by designing the tip with a diameter larger than the lead-out opening, creating an interference fit that preemptively prevents the clearance and inclination problem. The tip is preliminarily constrained by the lead-out opening structure before writing begins, eliminating the swaying issue that would otherwise occur during use.
Solution Approach 2:
The patent changes the dimensional parameters of the tip and lead-out opening relationship. Instead of the conventional design where the opening is larger than the cartridge diameter, this patent makes the tip diameter larger than the lead-out opening inner diameter, transforming the clearance-based design into an interference-fit-based design to achieve tip stability.
2Stability of the object's composition
If the tip outer diameter is made larger than the lead-out opening inner diameter to press the tip against the opening and prevent swaying, then tip stability is improved, but the switching device complexity increases due to the need for limiting member, shifting member, resetting member, and deformable member
Solution Approach 1:
The patent merges multiple functions into the switching device structure. The limiting member, shifting member, resetting member, and deformable member work together as an integrated system to achieve both tip extension/retraction and tip stabilization. The deformable member particularly serves dual purposes by enabling the shifting member to overcome the interference fit during extension while also contributing to the retraction mechanism.
Solution Approach 2:
The patent introduces dynamic elements to the switching device, particularly the deformable member which can change its physical state during operation. The shifting member dynamically moves between different positions (first position, second position, third position) to control the tip extension and retraction, adapting to the interference fit conditions during each phase of operation.
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
The design effectively reduces the probability of errors in handwriting by ensuring the tip remains consistently pressed against the lead-out opening, preventing swaying and maintaining stable ink flow during writing.
Implementation Method 1
the deformable member can be compressed and deformed by between the shifting member and the ink cartridge, allowing the shifting member to be further moved from the third position to the second position
Implementation Method 2
The resetting member can elastically bring the tip from the extended position to the retracted position
Data Source
AI summary
A retractable pen includes a barrel, an ink cartridge, a limiting member, a shifting member and a deformable member. When the shifting member is moved relative to the limiting member between a first position and a third position, the ink cartridge can be moved from a retracted position to an extended position or from the extended position to the retracted position. When the ink cartridge is located at the extended position, the deformable member can be further compressed by between the shifting member and the ink cartridge, allowing the shifting member to be moved further from the third position to a second position closer to the ink cartridge. When the shifting member is located at the second position, the ink cartridge is continuously held to the extended position and pressed against a lead-out opening of the barrel without the risk of swaying when a user writes with the retractable pen.