Retractable Writing Instrument Radially Flexible Elastic Tab Locking
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Solution Overview
Problem
Existing writing instruments with retractable protective elements are not easily actuable, particularly for young children, and are prone to clip breakage due to required agility and flexibility, which increases the risk of mechanical failure.
Innovation Solution
A writing instrument design featuring a radially flexible elastic tab connected to the locking member that can be pressed inward to disengage from a stop, allowing the protective element to slide back into protection position using an elastic return element, eliminating the need for external clips and reducing the risk of getting stuck.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a spring clip with ridged area is used to allow the user to push the protective element rearward into the retracted position, then the protective element can be positioned for writing, but the required agility and flexibility increases the risk of clip breakage
Solution Approach 1:
The patent changes the physical parameters of the locking mechanism by using a radially flexible elastic tab instead of a rigid spring clip. The elastic tab can be pressed radially inward to disengage the locking member from the stop, allowing the protective element to slide back into the protection position. This parameter change reduces the risk of breakage while maintaining ease of operation.
Solution Approach 2:
The patent introduces dynamic flexibility into the locking mechanism through the radially flexible elastic tab. The tab can dynamically deform radially inward when pressed by the user's finger, allowing easy disengagement of the locking member. This dynamic behavior eliminates the need for high agility and flexibility required by rigid spring clips.
2Ease of operation
If the unlocking portion is made thin to provide flexibility, then the locking mechanism can be actuated, but the risk of clip breakage increases
Solution Approach 1:
The patent changes the structural parameters by making the elastic tab radially flexible rather than requiring it to be thin and fragile. The tab has sufficient material thickness to resist breakage while maintaining radial flexibility through its elastic properties. This allows the unlocking portion to be both flexible and strong.
Solution Approach 2:
The elastic tab is made from an elastomeric material that combines flexibility and strength. This composite material property allows the tab to deform radially inward for unlocking while maintaining sufficient structural integrity to resist breakage during normal use.
3Reliability
If an external clip is used to maintain the retracted position, then the protective element can be locked, but the device complexity increases
Solution Approach 1:
The patent merges the locking member and unlocking portion into a single integrated component. The locking member is formed as one piece with the unlocking portion, eliminating the need for separate external clips. This integration maintains locking reliability while reducing device complexity.
Solution Approach 2:
The elastic tab serves multiple functions: it acts as the locking member when engaged with the stop, serves as the unlocking portion when pressed radially inward, and provides structural support for the protective element. This multi-functionality eliminates the need for separate components.
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 easy actuation of the protective element with minimal effort, reducing the risk of mechanical failure and making it suitable for users of all ages, including children, while maintaining robustness and simplicity.
Implementation Method 1
an elastic return element for biasing the protective element towards the protection position
Implementation Method 2
a radially flexible elastic tab which is connected to the locking member and can be pressed radially inwards
Data Source
AI summary
A writing instrument includes a body extending between a rear end and a front end of the body which has an opening, the body defining an inner volume; a writing member mounted inside the body and including a tip which protrudes from the front of the body; a protective element including a guide portion sliding along the body and a protective end which extends the guide portion and has an opening to allow the tip to pass through, the protective element being movable between a tip protection position and a retracted position for writing; an elastic return element coupled with the guide portion in order to bias the protective element towards the protection position; and a system for locking the retracted position.