Telescopic FRP Umbrella Shank Design
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Solution Overview
Problem
Conventional telescopic umbrella shanks made of fibre-reinforced plastic (FRP) face manufacturing difficulties due to non-uniform fiber lengths and polymer mixing, leading to poor precision and malfunction, while metal shanks are heavy and costly, making it challenging to create a lightweight and durable FRP shank with a telescopic mechanism.
Innovation Solution
A telescopic umbrella shank design featuring an inner FRP tube with a polygonal upper member and a cylindrical lower member, a fixing mechanism with a hexagonal section, and a linking mechanism with a spring member, allowing for generous clearances and reliable operation, while using a sleeve and thimble for secure assembly, and a buffer member for smooth movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If FRP is used for telescopic shank, then weight is reduced, but manufacturing precision deteriorates due to non-uniform fiber lengths and polymer mixing
Solution Approach 1:
The shank is divided into separate inner tube and outer tube components that can be manufactured independently with standard molding processes, then assembled together. This segmentation allows each component to be produced with acceptable tolerances without requiring high-precision eccentric molding, thus reducing weight while maintaining manufacturing feasibility.
Solution Approach 2:
The inner tube is nested within the outer tube to form the telescopic structure. This nesting arrangement allows both tubes to be made with standard circular cross-sections rather than complex eccentric shapes, significantly improving manufacturability while keeping the overall structure compact and lightweight.
2Weight of moving object
If FRP is used for shank, then weight is reduced, but positioning capability deteriorates because FRP cannot be machined
Solution Approach 1:
Positioning features such as recesses, protrusions, and alignment markers are pre-formed during the FRP molding process itself, rather than requiring post-manufacturing machining. This preliminary action ensures accurate positioning of the inner tube relative to the outer tube while maintaining the weight advantages of FRP construction.
Solution Approach 2:
A connecting mechanism with standardized interface features (such as recesses and protrusions) serves as an intermediary between the inner and outer tubes. This mediator enables precise positioning and secure assembly without requiring machining of the FRP tubes themselves, thus preserving weight reduction while achieving accurate alignment.
3Ease of manufacture
If metal is used for shank, then positioning and machining are possible, but weight increases
Solution Approach 1:
The shank uses composite construction with FRP tubes for the main structure (providing weight reduction) combined with a metal connecting mechanism (providing positioning and assembly capabilities). This composite approach achieves the benefits of both materials: lightweight FRP body with precise metal positioning features, eliminating the need for heavy metal construction throughout.
4Strength
If large diameter is used for shank, then structural strength is improved, but weight increases making it labor consuming
Solution Approach 1:
The shank employs FRP composite material construction which provides high strength-to-weight ratio. The fiber reinforcement in the FRP gives the large-diameter shank sufficient structural strength to support the umbrella canopy while keeping the weight low enough for easy carrying, unlike solid metal construction which would be too heavy.
Solution Approach 2:
The shank is segmented into telescopic inner and outer tube sections, allowing the overall structure to achieve necessary strength through the combined sections while each individual section maintains a manageable weight. The telescopic design also allows the strength to be distributed along the extended length rather than concentrated in a single heavy component.
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 achieves a lightweight, durable, and cost-effective telescopic FRP shank for large umbrellas, ensuring reliable operation and improved market competitiveness by addressing manufacturing challenges and weight reduction.
Implementation Method 1
the spring member urges against a bottom of the fixing mechanism and a top of the moving mechanism
Data Source
AI summary
An umbrella shank is provided with an FRP inner tube (10); an FRP outer tube (20) for receipt of the inner tube (10); a spring biased moving mechanism (30) including an upper member (31) having a longitudinal groove (311), and a lower member (32) having a longitudinal groove (321) aligned with the groove (311) wherein the lower member (32) is inserted into the inner tube (10), the upper member (31) is on the top of the inner tube (10), and the upper member (31) is in the outer tube (20); a fixing mechanism (40) in an upper portion of the outer tube (20); and a linking mechanism (60) in the outer tube (20) and including a rod (62) having a top secured to the fixing mechanism (40) and a bottom secured to a bottom of the lower member (32), and partially disposed in the grooves (311, 321).