Click Pen Inner Cylinder Assembly for Secure Rotor Retention
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Solution Overview
Problem
Existing writing instruments face challenges in ease of assembly and disassembly, with parts like the rotor being prone to unintentional detachment during refill replacement due to frictional resistance or weight, and the inside barrel detaching from the rear shaft under strong writing pressure.
Innovation Solution
A writing instrument design featuring a cylindrical first tubular member with elastically deformable parts that can deform radially inward or outward, facilitated by fitting parts on the second tubular member and inside member, allowing for easier assembly and disassembly by minimizing frictional resistance and securing the rotor and inside barrel during attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the elastically deformable part sticks out more to the inside to prevent rotor detachment, then the rotor is secured better, but the frictional resistance increases making assembly harder
Solution Approach 1:
The elastically deformable part is designed to dynamically change its shape during assembly and disassembly. When the second tubular member is inserted into the first tubular member, the elastically deformable part deforms to the inside to reduce friction and facilitate easy insertion. When the inside member is inserted, it deforms to the outside to engage with the inside member and prevent detachment, thus adapting its state to different operational phases.
Solution Approach 2:
The invention changes the geometric parameter of the elastically deformable part - specifically its radial projection distance. By making this parameter variable through elastic deformation rather than fixed, the system can optimize the projection distance for different stages: smaller projection during assembly for low friction, and larger projection during operation for secure engagement.
2Device complexity
If the rotor is inserted before attaching the inside barrel to the rear shaft, then assembly sequence is simplified, but the rotor drops off due to weight when the elastically deformable part does not deform inward
Solution Approach 1:
The elastically deformable part dynamically adjusts its radial position based on the assembly stage. During the initial insertion of the second tubular member into the first tubular member, it deforms inward to allow smooth passage. When the inside member is subsequently inserted, the elastically deformable part deforms outward to engage with grooves or protrusions on the inside member, preventing the rotor from dropping off due to gravity.
3Reliability
If the inside barrel is attached to the rear shaft by engagement, then secure attachment is achieved, but force from strong writing pressure transmits through the refill and rotor causing detachment
Solution Approach 1:
The elastically deformable part acts as an intermediary element between the second tubular member and the inside member. It provides a compliant connection that can absorb and distribute the forces generated during writing. The elastic deformation capability allows it to cushion impact forces and prevent direct transmission of high writing pressure that would otherwise cause detachment of the engaged connection.
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 enables easier assembly and disassembly of writing instruments, preventing unintentional detachment of parts during refill replacement and ensuring secure attachment, thereby improving usability and reusability.
Implementation Method 1
an elastically deformable part able to elastically deform to the outside and to the inside in the radial direction
Data Source
AI summary
A click-action writing instrument 1 comprises a rear shaft 20, an inner cylinder 30 having on a side surface thereof an elastic deformation portion 37 that can elastically deform radially outward and inward, and a rotor 40. The elastic deformation portion has a first protrusion 38 on the outer surface thereof. The elastic deformation portion has a second protrusion 39 on the inner surface thereof. The first protrusion 38 is configured to cause the elastic deformation portion to deform radially inward when the inner cylinder is inserted into the rear shaft. The second protrusion 39, in a state prior to insertion of the inner cylinder into the rear shaft, causes the elastic deformation portion to deform radially outward when the rotor is inserted into the inner cylinder. The deformed elastic deformation portion is configured to recover after the rotor is inserted.