Disappearance-style notebook
The retractable writing instrument addresses tip wobbling by using an annular member with notches and a guide surface, combined with a coil spring, for secure tip grip and improved operational stability.
JP7875738B2Active Publication Date: 2026-06-18PILOT PEN CO LTD
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- PILOT PEN CO LTD
- Filing Date
- 2022-06-20
- Publication Date
- 2026-06-18
AI Technical Summary
⚠Technical Problem
Existing retractable writing instruments face issues with tip wobbling during use, requiring high dimensional accuracy and precision in component interactions, which complicates assembly and increases the risk of malfunctions and user discomfort.
⚗Method used
A retractable writing instrument design featuring an annular member with notches and a guide surface that allows the inner diameter to shrink upon load application, coupled with a coil spring for relative movement, ensuring secure tip grip without looseness and reducing the risk of malfunctions.
🎯Benefits of technology
The design provides stable writing feel by preventing tip wobble and minimizing assembly complexities, ensuring smooth operation and reduced risk of malfunctions.
✦ Generated by Eureka AI based on patent content.
Smart Images
Figure 0007875738000001 
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Abstract
To provide a retractable writing instrument which prevents rattling of a tip in writing and provides stable writing feeling, and is less susceptible to an actuation failure.SOLUTION: A retractable writing instrument includes a barrel having an opening in a front end thereof, a tip holder which can move in an axial direction of the barrel, a tip which can retract along with a movement of the tip holder, an annular member which is fitted in an inner periphery of the opening of the barrel with a play therebetween and can move in the axial direction, and an elastic member which can connect the tip holder and the annular member to each other with their relative movement allowed. An abutment surface tapered toward a front end is formed in at least part of an outer periphery of the annular member. A cutout is formed in part of the annular member. The annular member is configured such that when receiving a load on the abutment surface, an inner diameter of the annular member is reduced. A plurality of cutouts are disposed with equal distances therebetween in a circumferential direction of the annular member. The abutment surface is provided such that it protrudes radially outward in each of intermediate positions of two adjacent cutouts in a circumferential direction of the cutouts, as seen from the circumferential direction.SELECTED DRAWING: Figure 3
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