Writing Instrument Cap With Segmented Seal And Soft Outer Layer
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Solution Overview
Problem
Existing writing instrument caps do not provide an effective airtight seal and can pose safety risks due to hard materials that may damage teeth when chewed on, and they often require additional membranes for sealing, which can be unnecessary and potentially harmful.
Innovation Solution
A writing instrument cap composed of two components, featuring a rigid inner core made of semicrystalline plastic for a secure seal and a softer outer layer of silicone rubber with antimicrobial properties, eliminating the need for internal membranes and reducing the risk of injury during chewing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hard plastic cap is used to ensure tight sealing and prevent displacement, then the airtight seal and cap stability are improved, but the risk of dental damage when chewed on increases
Solution Approach 1:
The cap is divided into two functional layers: an inner core made of hard plastic for sealing and an outer layer made of softer material for safety. This segmentation allows each layer to perform its specific function without compromising the other.
Solution Approach 2:
The cap uses a composite structure combining hard plastic (inner core) and softer material (outer layer). This composite approach integrates the advantages of both materials: the hard plastic provides dimensional stability and sealing, while the softer outer layer provides safety during chewing.
2Reliability
If a membrane is added within the cap to enhance the airtight effect, then the sealing performance is improved, but the device complexity and potential harm from additional barriers increase
Solution Approach 1:
The membrane component is removed from the cap structure. The airtight sealing function is achieved directly through the engineered interface between the inner core and main body, eliminating the need for an additional membrane barrier.
Solution Approach 2:
The sealing mechanism relies on precise dimensional parameters and material properties of the inner core and main body interface rather than an additional membrane. The hard plastic material's dimensional stability ensures consistent sealing without requiring extra components.
3Object-affected harmful factors
If the cap material is made softer to reduce chewing damage risk, then user safety is improved, but the ability to form a tight airtight seal deteriorates
Solution Approach 1:
The cap is segmented into an inner core for sealing and an outer layer for safety. The inner core maintains hard plastic properties for tight sealing, while the outer layer provides softer, safer contact during chewing.
Solution Approach 2:
Different parts of the cap have different material properties: the inner core has hard plastic properties for sealing, while the outer layer has softer properties for safety. This local differentiation of material quality allows both functions to coexist.
Data Source
AI summary
A writing instrument according to the present disclosure comprises a main body, a writing tip and a cap, wherein the cap is designed to be secured tightly on the main body such that the writing tip is covered by the cap. The cap comprises of an inner core and an outer layer, wherein a material of the outer layer is softer compared to a material of the inner core. With that, it is possible to design an air-tight (or almost air-tight) fitting cap for a writing instrument. With the softer outer layer of the cap, it is achieved that a user chewing on the cap has a reduced risk of damaging his/her teeth. In addition, although a membrane within the cap may still be present, such membrane is no longer necessary. The membrane may be an additional barrier contributing further to the air-tight effect of the cap that is present within the cap.