Bicycle Inner-Tube Valve Housing Segmentation
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Solution Overview
Problem
Existing bicycle inner-tube valve assemblies suffer from damage to both the pump head and the inner-tube due to the interaction with external threads during inflation, and the reduced wall thickness of inner-tubes leads to increased air leaks and flat tires near the valve housing.
Innovation Solution
The inner-tube assembly features a valve housing with a threaded lower portion for rim attachment and an unthreaded upper portion for pump head engagement, along with a reduced valve patch aspect ratio to minimize damage and leaks, including a threaded tip for valve cap attachment and a tapered rubber patch for securement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If external threads are provided on the valve housing to facilitate attachment of valve caps and locking nuts, then the ease of operation is improved, but the pump head is damaged during engagement and removal requires significant force
Solution Approach 1:
The valve housing is divided into two distinct portions: a lower threaded portion for securing the valve to the rim, and an upper unthreaded portion for pump head engagement. This segmentation allows each portion to serve its specific function without the harmful effects of threads during pump operations.
Solution Approach 2:
Different portions of the valve housing have different surface characteristics: the lower portion has threads for secure attachment to the rim, while the upper portion has a smooth unthreaded surface for gentle engagement with the pump head. This local differentiation of properties prevents pump head damage while maintaining secure valve attachment.
2Weight of moving object
If the wall thickness of inner-tubes is reduced to decrease bicycle weight, then the weight is decreased, but the frequency of flat tires caused by air leaking through holes increases
Solution Approach 1:
A reinforced patch is applied beforehand to the inner-tube at the location where the valve housing will be attached. This patch creates a strengthened zone that prevents the formation of holes and air leaks, compensating for the reduced wall thickness of modern lightweight inner-tubes.
3Ease of manufacture
If the valve housing is secured to the inner-tube using a rubber patch, then the valve can be attached to the inner-tube, but holes frequently form in the inner-tube near the valve housing causing air leaks
Solution Approach 1:
A reinforced patch is applied to the inner-tube at the valve attachment location before mounting the valve housing. This pre-reinforcement prevents holes from forming in the vulnerable area around the valve, eliminating air leaks while maintaining the ease of patch-based attachment.
Data Source
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AI summary
An inner-tube assembly that includes an inner-tube (48) and a valve assembly (52). The valve assembly (52) is configured to facilitate the inflation of the inner-tube, and the valve assembly includes a valve core (68) and a valve housing (56). The valve housing (56) has a lower portion (58) coupled to the inner-tube and an opposite upper portion (60). At least part of an exterior surface of the lower portion (58) is threaded and at least part of an exterior surface of the upper portion (60) is unthreaded. In another aspect, the inner-tube assembly includes the inner-tube (48) and a valve assembly (52). An attachment member (74) couples the valve assembly to the inner-tube. The attachment member (74) has a length and a width defining an aspect ratio of width/length, and the aspect ratio is less than about 0.50.