Modular Screw With Rotatable Washer for Low-Torque Prestressing
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Solution Overview
Problem
Existing screw technologies lack adaptability to different mechanical requirements, fail to perform multiple functions, and often require higher torque for prestressing, while being costly and complex to produce.
Innovation Solution
A modular screw design featuring a screw head, shank with a rotatable washer for force distribution, a clamping disk for prestressing, and an external thread, allowing for adjustable diameters and reduced friction, along with a compression-limiting portion to prevent creep and damage, produced through simplified rolling and heat-treating processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional screw design is used, then the structure is simple, but the adaptability to different mechanical requirements is poor
Solution Approach 1:
The screw is divided into modular functional portions (first functional portion with clamping disk, second functional portion with washer, third functional portion for force distribution, fourth functional portion with external thread) that can be independently configured to meet different mechanical requirements, allowing customization without increasing overall structural complexity
Solution Approach 2:
The screw design integrates multiple functions into a single component: the clamping disk provides prestressing, the washer distributes forces, the third functional portion distributes prestressing force, and the external thread provides fastening. This multi-functional design allows one screw to adapt to various mechanical requirements
2Force
If a conventional screw without force distribution is used, then the structure is simpler, but the prestressing force application is less efficient
Solution Approach 1:
The third functional portion is specifically designed to distribute prestressing force locally across the fastened components, concentrating the force distribution function where needed rather than relying on the entire screw structure, thereby improving prestressing efficiency without excessive complexity
3Ease of operation
If a fixed washer is used, then the washer position is stable, but friction during tightening increases
Solution Approach 1:
The washer is designed to be rotatable about the longitudinal axis during tightening operations, allowing it to rotate and reduce friction between the washer and the fastened component surface. This dynamic capability reduces energy loss during tightening while the washer remains axially positioned
4Reliability
If multiple separate components are used to achieve these functions, then each function can be optimized, but the production cost and complexity increase
Solution Approach 1:
Multiple functional elements (clamping disk, washer, force distribution portion, external thread) are merged into a single integrated screw component manufactured through rolling and heat-treating processes. This consolidation maintains the functional performance of separate components while reducing production cost and assembly complexity
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 prestressing forces with lower torque, is adaptable to various mechanical needs, and reduces production costs by integrating components in a single process, ensuring secure and efficient fastening without damaging components.
Implementation Method 1
Clamping disks are spring elements, e.g., in the form of a disk spring, whose securing effect is based solely on traction. They are intended to counteract a loosening of a screw connection, for example due to embedding loads, by maintaining a sufficiently high prestressing in the connection by means of spring forces.
Implementation Method 2
Washers or shims are annular disks that can be folded over a shank of a screw and are usually made of metal. 'Enclosed' between the screw head and the part to be fastened with the screw, the washer serves to transfer the force exerted from the bottom of the screw head to a larger surface area of the part in question
Implementation Method 3
Because the modular screw has a third functional portion for distributing a prestressing force, wherein a washer is arranged in the third functional portion and is mounted so as to be rotatable about a longitudinal axis of the screw, and wherein the washer is secured in an approximately positionally fixed manner in the axial direction by bearing against the second and the fourth functional portion, a modular screw is formed where the washer contacts a component surface and rotates only slightly or not at all during tightening. In this way, an improved fastening operation is provided, because there is little to no frictional force between the rotatably mounted washer and a corresponding component surface
Implementation Method 4
Compression limiters are metal inserts that are usually provided for use in plastic moldings. The compression limiter resists a compressive force created during assembly of a counterscrew or bolt. By using a compression limiter, damage to components to be fastened is prevented. In addition, creep is prevented, and a compressive force is maintained in the connection.
Data Source
AI summary
A modular screw is provided, wherein the screw includes, in an axial direction, the following elements: a screw head, a shank having a second functional portion, a third functional portion for distributing a prestressing force, wherein a washer is arranged in the second functional portion and is mounted so as to be rotatable about a longitudinal axis of the screw, and a fourth functional portion having an external thread, and wherein the washer is secured in an approximately positionally fixed manner in the axial direction by bearing against the second and the fourth functional portion.