Expandable Baton Locking Structure With Replaceable Inner Tubes
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Solution Overview
Problem
Conventional expandable batons face issues with increased weight and manufacturing difficulties due to the greater wall thickness required for locking mechanisms, and frequent wear on inner surfaces leading to instability of inner support tubes.
Innovation Solution
The design incorporates replaceable inner support tubes with external threads that are secured to internal threads on the main tube, allowing for easy replacement when worn, and a lock mechanism with annular grooves and elastic members for secure locking without the need for increased wall thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an annular groove is formed on the inner surface of the larger tube for locking the smaller tube, then the locking function is improved, but the wall thickness must be increased which greatly increases weight and manufacturing difficulty
Solution Approach 1:
The locking function is segmented from the larger tube structure. Instead of forming the annular groove directly in the larger tube wall (which would require increased wall thickness), the locking mechanism is separated into a distinct component - the smaller tube with its own locking structure that interfaces with the larger tube through a standard-sized annular groove. This allows the larger tube to maintain its original wall thickness while still achieving reliable locking.
Solution Approach 2:
The smaller tube acts as an intermediary element between the locking requirement and the larger tube structure. It provides the locking interface through its own geometry and locking mechanism, mediating the interaction between the two tubes without requiring the larger tube to be structurally modified to accommodate the locking groove, thus avoiding increased wall thickness and weight.
2Reliability
If the wall thickness of the larger tube is increased to accommodate the annular groove, then the locking structure is improved, but manufacturing difficulty greatly increases
Solution Approach 1:
The manufacturing complexity is segmented away from the larger tube. The annular groove and locking features are implemented on the smaller tube, which is a separate, more manageable component. This allows the larger tube to be manufactured using standard processes without the need for complex thick-wall groove formation, significantly easing manufacturing while maintaining reliable locking structure.
Solution Approach 2:
The patent treats the smaller tube as a replaceable, relatively simple component that can be manufactured economically. By placing the complex locking geometry on this smaller, easier-to-manufacture tube rather than on the larger tube, the overall manufacturing difficulty is reduced. The smaller tube can be produced cost-effectively with precise locking features without requiring expensive tooling or processes.
3Ease of operation
If the smaller tube is frequently retracted and extended relative to the larger tube, then the operational flexibility is improved, but the inner surface of the larger tube wears quickly causing instability
Solution Approach 1:
The smaller tube is designed as a replaceable component with a service life matched to its wear characteristics. Since it undergoes frequent movement and wear, it is intended to be replaced periodically. This allows the system to maintain high operational flexibility while accepting that the smaller tube will wear and needs replacement, rather than trying to make the entire assembly permanent and maintenance-free.
Solution Approach 2:
The smaller tube is designed to be discarded after a certain period of use when wear reduces its effectiveness. The replaceable design allows for easy removal and replacement of the worn smaller tube, recovering the valuable larger tube structure while replacing only the worn component. This maintains operational flexibility over the long term through periodic maintenance rather than requiring the entire assembly to be durable indefinitely.
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 solution reduces the weight and manufacturing complexity of the baton, allows for cost-effective replacement of worn components, and maintains the structural integrity and functionality of the expandable baton.
Implementation Method 1
two first elastic members 152 and two second elastic members 212, the first and second elastic members 152, 212 enabling the first and second lock protuberances 151, 211 to return to the first and second annular groove 14, 41
Data Source
AI summary
An expandable baton includes an internally threaded first tube; a first inner support tube disposed in the first tube and including first external threads secured to the internal threads of the first tube; a second inner support tube spaced from the first inner support tube with a first annular groove formed between them; a second lock mechanism at a first end of the second tube; a first lock mechanism at a first end of the first tube; a release mechanism including an axially moveable lock needle having a pointed second end, a pushbutton and a spring, a pressing of the pushbutton moves the lock needle to either insert into or disengage from the second lock mechanism, thereby unlocking the second lock protuberances or locking same; and a positioning member for limiting the release mechanism.