Captive Screw Sleeve Structure for Simple Retention Assembly
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Solution Overview
Problem
Conventional captive screws have complex structures, making assembly difficult and are prone to screw detachment from the sleeve, leading to potential loss during disassembly.
Innovation Solution
A simplified captive screw design featuring a sleeve with a positioning protrusion forming a channel, where the screwing member's wider section passes through, ensuring it cannot detach without additional blocking components, facilitating assembly and preventing loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional captive screw structures are used, then the screwing member can be retained in the sleeve, but the structure becomes complicated and assembly becomes difficult
Solution Approach 1:
The threaded portion of the screwing member is segmented into a wider section and a narrower section, with the wider section serving as a stopping section that engages with the positioning protrusion in the sleeve. This segmentation allows the screw to be retained in the sleeve without requiring complex additional components, thereby simplifying the overall structure while maintaining reliability.
2Reliability
If conventional captive screw structures are used, then the screwing member can be retained in the sleeve, but the assembly process becomes complicated
Solution Approach 1:
The wider section of the screwing member automatically engages with the positioning protrusion in the sleeve during the assembly process, without requiring additional blocking components or complex assembly steps. The design enables the screw to self-retain in the sleeve through its own structural features, thereby simplifying the assembly process while ensuring reliable retention.
3Reliability
If additional blocking components are installed to prevent screw detachment, then the screwing member can be securely retained, but the structure becomes more complex
Solution Approach 1:
The patent extracts the blocking function from separate additional components and integrates it directly into the screwing member itself through the wider section design. This wider section acts as an inherent stopping section that engages with the positioning protrusion, eliminating the need for separate blocking components and thereby simplifying the overall structure while maintaining effective detachment prevention.
4Reliability
If the channel diameter is reduced to prevent screw detachment, then the screwing member is securely retained, but the assembly becomes more difficult
Solution Approach 1:
The patent applies local quality by creating a wider section with a larger diameter at the specific location where the screwing member interacts with the positioning protrusion. This localized enlargement allows the screw to be securely retained by the positioning protrusion while maintaining ease of assembly, as the wider section is specifically positioned to engage with the positioning protrusion without requiring the entire channel to be smaller.
Data Source
AI summary
A captive screw includes a sleeve and a screwing member. The sleeve includes a body portion and a positioning protrusion. The positioning protrusion protrudes from the body portion, and forms a channel. The screwing member includes a head portion, a neck portion and a threaded portion. The neck portion connects the head portion and the threaded portion. The neck portion passes through the channel. The head portion and the threaded portion are located on the positioning protrusion. The threaded portion includes a wider section and a narrower section. The wider section is connected to the neck portion. The narrower section is connected to the wider section. The diameter of the channel is less than a major diameter of the wider section. The diameter of the channel is greater than or equal to a major diameter of the narrower section and a minor diameter of the wider section.