Inclined-Washer Fastening Structure for Reusable Anti-Loosening Bolts
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Solution Overview
Problem
Conventional anti-loosening devices, such as locking pin mechanisms, often damage threaded rods when loosened for maintenance, preventing reuse and being costly due to complex mechanisms.
Innovation Solution
A fastening structure featuring a washer with an inclined surface and a machine screw that screws into a nut at an orthogonal angle, utilizing a cradle for contact, allowing for easy loosening and re-tightening without damaging the threaded rod, and providing a higher frictional resistance to prevent loosening due to vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking pin mechanism is used to expand the internal surface of the nut for fastening, then anti-loosening effect is generated, but the threaded rod is damaged and cannot be reused
Solution Approach 1:
The patent introduces a washer with an inclined surface as an intermediary component between the nut and the object to be fastened. The machine screw acts as a mediator that, when screwed into the nut, presses against the inclined surface to generate anti-loosening force without contacting or damaging the threaded rod. This intermediary mechanism transfers the locking function from direct contact with the threaded rod to contact with the washer's inclined surface.
2Reliability
If a locking pin is made to dig into the external thread for greater anti-loosening effect, then fastening reliability is improved, but the threaded rod is damaged and cannot be reused
Solution Approach 1:
The washer with inclined surface serves as an intermediary that receives the pressing force from the machine screw and converts it into anti-loosening force on the nut. The machine screw, when screwed into the nut at an angle, presses against the inclined surface, generating a component of force that pushes the nut against the washer, creating friction that prevents loosening without the need for the locking pin to dig into the threaded rod.
3Reliability
If conventional anti-loosening devices with complex mechanisms are used, then anti-loosening effect is achieved, but cost increases due to complex mechanism and machining
Solution Approach 1:
The patent divides the anti-loosening function into separate simple components: a standard nut, a washer with an inclined surface, and a machine screw. Each component has a simple structure that can be manufactured using standard processes. The anti-loosening effect is achieved through the geometric relationship and friction between these segmented components rather than through a complex integrated mechanism.
Solution Approach 2:
The patent changes the geometric parameter of the washer by introducing an inclined surface with a specific angle. This parameter change transforms the simple pressing action of the machine screw into an effective anti-loosening mechanism. By adjusting the inclination angle, the balance between the fastening force and the anti-loosening friction force can be optimized without complicating the overall structure.
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
Enables the reuse of threaded rods by preventing damage during loosening and maintaining secure fastening without excessive loosening due to vibration, while simplifying the fastening process and reducing the need for complex mechanisms.
Implementation Method 1
the inclined surface has a smaller coefficient of friction than the second side of the washer... as the inclined surface has a smaller coefficient of friction than the second side, the machine screw is forced to climb the inclined surface to generate a force to press the washer against the to-be-fixed member, thereby preventing the nut from loosening
Data Source
AI summary
A fastening structure inserts a threaded rod 11a of a bolt 11 through a fixing hole 12a of a to-be-fixed member 12 in a manner such that an end portion of the threaded rod protrudes from the fixing hole, and screwing a machine screw 15 with a proper torque into a nut 14 which is provided on the end portion via a washer 13. The washer has an inclined surface 13c formed on a first side 13b which faces the nut, and has a flat surface formed on a second side 13d. The machine screw is screwed into the nut in a direction such that an axis is orthogonal to the inclined surface 13c. The first side (the inclined surface) and the second side of the washer have a different surface roughness, and the first side has a smaller coefficient of friction than the second side.