Chair Foot Ring with Threaded Braking Blocks for Low-Cost Fastening
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing foot ring designs for chairs face challenges in balancing holding strength and cost, particularly for low-cost manufacturing, and require separate maintenance of braking components to reduce maintenance costs.
Innovation Solution
A foot ring structure featuring a ring body with a sleeve and bushing, where the bushing has a conic inner surface with an inner thread and the positioning base has movable braking blocks with outer threads, allowing independent replacement and adjustment for enhanced holding and reduced costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a levered quick release device is used to implement sliding and positioning, then holding strength and operating convenience are improved, but manufacturing cost increases significantly
Solution Approach 1:
The quick release device is divided into separate functional components: a lever component for actuation, a locking component with engagement features, and a body component. This segmentation allows each part to be manufactured independently using simpler, lower-cost processes while maintaining the overall functionality of the device.
Solution Approach 2:
The complex levered quick release mechanism is extracted from the inner sleeve, eliminating the need to machine threads into the sleeve itself. The locking functionality is taken out and implemented through separate locking components that engage with the post, reducing manufacturing complexity and cost.
2Strength
If claw plates are integratedly connected to the inner sleeve to increase holding force, then fastening capability is improved, but the deforming range is limited and maintenance cost increases when elastic fatigue occurs
Solution Approach 1:
The braking blocks are segmented from the positioning base, allowing them to be independently replaced when worn or fatigued. This separation enables maintenance of only the braking blocks rather than replacing the entire inner sleeve assembly, reducing maintenance costs.
Solution Approach 2:
The braking blocks are designed as consumable components that can be easily replaced when they wear out or lose elastic properties. This approach is more economical than attempting to extend the life of integrated claw plates, as the simple braking blocks can be manufactured at low cost and replaced frequently without significant expense.
3Ease of operation
If the inner sleeve is machined to provide a thread, then the foot ring can be fastened, but manufacturing cost cannot be effectively reduced
Solution Approach 1:
The threading function is extracted from the inner sleeve and transferred to separate braking blocks. This eliminates the need to machine threads into the sleeve, significantly reducing manufacturing complexity and cost while maintaining the fastening capability through the screw engagement of the braking blocks with the post.
Solution Approach 2:
The braking blocks serve as intermediary components between the foot ring and the post. They provide the threading function through their outer threads that engage with the inner threads of the post, eliminating the need to machine threads directly into the inner sleeve while maintaining fastening capability.
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
This design provides a cost-effective solution with balanced holding strength and convenience, enabling independent replacement of braking blocks to reduce maintenance costs and maintain operational efficiency.
Implementation Method 1
The inner surface is provided with an inner thread. The outer surface of each braking block is provided with an outer thread and slightly protrudes from the positioning base. The outer surfaces of the braking blocks jointly form a conic shape corresponding to the inner surface of the bushing. The outer thread screwing with the inner thread of the bushing.
Implementation Method 2
The bushing presses the braking blocks to move toward the post to fasten the foot ring onto the post
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A chair includes a seat (12), a post (11), a foot ring (2), a bushing (23) and a positioning base (22). The post (11) is connected to the seat (12). The foot ring (2) has a ring body (21) and a sleeve (211). The bushing (23) is fastened in the sleeve (211) and has a conic inner surface (232). The inner surface (232) tapers upward. The inner surface (232) has an inner thread (233). The positioning base (22) is of a tubular shape and axially fastened onto the post (11). The positioning base (22) has openings (221). Each opening (221) is embedded by a braking block (222). An outer surface of each braking block (222) has an outer thread (2223). The outer surfaces of the braking blocks (222) jointly form a conic shape corresponding to the inner surface (232) of the bushing (23). The outer thread (2223) screws with the inner thread (233). The bushing (23) presses the braking blocks (222) to move toward the post (11) to fasten the foot ring (2) onto the post (11) when the foot ring (2) is rotated.