Torque-Limiting Knob Structure for Wear-Resistant Fastening
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Solution Overview
Problem
Existing knobs experience wear and breakage due to strong central load on the screw axis, and are susceptible to unauthorized torque modifications, leading to potential damage during the tightening phase.
Innovation Solution
A knob design featuring a glass-shaped casing with a central bush, slider, and springs, which allows for controlled torque transmission and quick disengagement, utilizing a radial scale for torque adjustment and a cover element for secure engagement, ensuring consistent torque application and preventing unwanted modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a central screw is used to connect the knob to the body, then the knob can be securely fixed, but strong central load causes wear and sudden breakage
Solution Approach 1:
The connection mechanism is segmented from a single central screw connection into a distributed system with multiple engagement points. The knurled surface provides numerous small engagement points around the circumference, distributing the load away from the central axis and reducing wear on any single point while maintaining secure fixation.
2Ease of manufacture
If the knob structure is made simple for easy manufacturing, then production cost is reduced, but it becomes susceptible to unauthorized modifications
Solution Approach 1:
The knob incorporates a knurled surface with a specific pitch and pattern that provides both functional grip and security. The local quality of the knurled texture creates friction and mechanical interlocking that prevents unauthorized modifications while maintaining simple overall manufacturing. The specific geometry of the knurls provides tamper resistance without requiring complex additional components.
3Force
If the knob allows rotation during tightening phase, then torque limitation is achieved, but operator may exceed forcing and cause damage
Solution Approach 1:
The knob transitions from a static connection to a dynamic engagement system. During tightening, the knurled surface allows controlled rotation with torque limitation through friction and mechanical interlocking. The dynamic interaction between the knurls and the surface provides automatic torque control while maintaining operator control, preventing excessive forcing through the inherent friction characteristics of the knurled engagement.
4Productivity
If the knob is designed for quick disengagement, then operational speed is improved, but securing strength during use may be compromised
Solution Approach 1:
The knurled surface engagement system is self-locking during use through friction and mechanical interlocking, providing secure fixation without additional locking mechanisms. For quick disengagement, the user simply applies reverse rotation force that overcomes the friction, allowing the knob to self-release without requiring tools or complex release mechanisms. The same knurled structure provides both securing strength during use and quick release 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
The design provides significant resistance to wear, allowing over 100,000 cycles without failure and ensuring safe operation by maintaining consistent torque, reducing the risk of damage and unauthorized modifications.
Implementation Method 1
a spring (6) exerting a force on said slider (5)
Implementation Method 2
a knurled surface (12) apt to go into abutment against a knurled surface (12') of a fixed body, said knurled surface (12) being in coaxial alignment with said central opening (2c)
Data Source
Figure 1~2
Figure 3~4a
Figure 4b
AI summary
Knob for connecting an object to a fixed body, consisting of an external hollow gripping element (1) apt to house means for the engagement with said object and with said fixed body, characterised in that said engagement means consist of a glass-shaped body (2) with a central hole combined with a fixed internal body consisting of a glass-shaped body (3) which houses within torque adjusting means.