Modular Screw With Rotatable Washer for Higher Preload
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Solution Overview
Problem
Existing screw technologies lack flexibility and adaptability to different mechanical requirements, often resulting in insufficient preload force and higher tightening torque, with complex and costly manufacturing processes.
Innovation Solution
A modular screw design featuring a screw head, a shaft with multiple functional sections, including a tension washer and a compression limiting section, allowing for adjustable preload force distribution and simplified production through integrated rolling and coating processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional screw design with integrated washer is used, then the structure is simple, but the preload force is insufficient and tightening torque is high
Solution Approach 1:
The screw is divided into modular functional sections: a screw head, a shaft with external thread, and a separately attachable washer. This segmentation allows each component to be optimized independently - the washer can be designed specifically for preload force distribution while the screw provides structural support, achieving higher preload force without requiring a complex integrated structure.
Solution Approach 2:
The washer serves multiple functions: it distributes preload force over a larger area, reduces friction during tightening, and can be attached to different screw types. This multi-functionality allows the system to achieve higher preload force with lower tightening torque while maintaining structural simplicity through a versatile component design.
2Adaptability or versatility
If a modular screw with multiple functional sections is used, then adaptability to different mechanical requirements is improved, but manufacturing complexity increases
Solution Approach 1:
The screw is manufactured as separate functional sections (screw head, shaft with external thread, washer) that can be produced using standard manufacturing processes. This segmentation enables each component to be manufactured independently with optimized processes, then assembled through simple attachment mechanisms, achieving modularity without significantly increasing manufacturing complexity.
Solution Approach 2:
The manufacturing process merges the production of multiple components into an integrated workflow where the screw and washer are manufactured separately using conventional methods, then combined through a simple attachment process. This approach maintains ease of manufacture by using existing manufacturing capabilities while achieving adaptability through modular design.
3Ease of operation
If a washer is freely rotatable in the unthreaded section, then the washer can be easily positioned, but the washer may rotate during tightening causing friction and reducing preload efficiency
Solution Approach 1:
The washer is attached to the screw shaft in advance during manufacturing or assembly, positioning it in the optimal location on the shaft before the tightening operation. This preliminary attachment ensures the washer remains stationary during tightening, eliminating rotation-related friction and maximizing preload force efficiency, while still allowing easy positioning during the attachment phase.
Solution Approach 2:
The screw shaft acts as an intermediary between the washer and the tightening operation. By providing a defined attachment interface on the shaft, the system controls the washer's position and prevents unwanted rotation during tightening, while maintaining ease of positioning during assembly through the standardized attachment mechanism.
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 modular screw achieves higher preload force with lower tightening torque and reduced manufacturing costs, enabling easy adaptation to various mechanical requirements while minimizing frictional forces and preventing component damage.
Implementation Method 1
A disc spring is arranged in the unthreaded section, wherein a through-hole of the disc spring has a larger diameter than the threaded section and, in particular, than the unthreaded section, so that the disc spring is freely rotatable and axially displaceable in the unthreaded section
Implementation Method 2
Washers are ring-shaped discs, usually made of metal, that can be placed over the shank of a screw. Positioned between the screw head and the part being fastened, they serve to distribute the force exerted on the underside of the screw head over a larger area of that part
Implementation Method 3
They are intended to counteract loosening of a bolted connection, such as due to settling, by maintaining a sufficiently high preload in the connection through spring forces
Data Source
Figure 1~6
Figure 7~14
Figure 15~20
AI summary
According to the invention, a modular screw (1) is provided, wherein the screw comprises the following elements in an axial direction: a screw head (4), a shank (11) with a second functional section, a third functional section for distributing a preload force, wherein a washer (16) is arranged in the second functional section, which is rotatably mounted about a longitudinal axis of the screw, and a fourth functional section with an external thread, and wherein the washer is fixed in an axial direction approximately by contact with the second and the fourth functional section.