Self-Locking Screw Connection With Resilient Catch Grid
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Solution Overview
Problem
Existing self-locking screw connections face challenges in ease of production, mounting, and precision adjustment, with limited pre-stress resolution and axial play adjustment, often requiring additional work steps and difficulty in loosening.
Innovation Solution
A self-locking screw connection featuring a polygonal nut with an intermediate washer secured against rotation, equipped with resilient sheet-metal catches that form a positive lock with a grid on the washer, allowing for precise adjustment and easy mounting, and featuring a ratchet mechanism for improved pitch angle resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plastic insert is used to restrict thread mobility, then self-locking is achieved, but stiffness of the screw connection increases
Solution Approach 1:
A resilient catch element acts as an intermediary between the nut and the intermediate washer, providing self-locking through elastic deformation rather than rigid mechanical restriction. The catch element flexibly engages with the grid structure, allowing controlled movement while maintaining the self-locking function without excessive stiffness.
Solution Approach 2:
The catch element's resilient properties allow it to change its mechanical state dynamically - flexing during tightening to engage the grid, then maintaining engagement through elastic recovery. This parameter change enables self-locking while accommodating slight movements, reducing overall connection stiffness compared to rigid plastic inserts.
2Reliability
If a splint pin is provided in the screw section, then the nut is prevented from loosening, but additional work steps for attaching the splint are required
Solution Approach 1:
The catch element is designed to automatically engage with the grid on the intermediate washer during the normal tightening process, without requiring separate attachment steps. As the nut is screwed onto the screw section, the resilient catch elements flex and naturally lock into the grid positions, providing self-locking functionality as an integrated feature rather than a separate assembly step.
3Reliability
If an intermediate washer with a polygon profile is used, then a positive lock is formed, but additional work steps after screwing are necessary
Solution Approach 1:
The grid structure is pre-formed on the intermediate washer with positions that correspond to the catch element engagement points. During the tightening process, the resilient catch elements automatically engage with these pre-positioned grid points, establishing the positive lock as part of the normal assembly sequence rather than requiring subsequent adjustment or locking steps.
4Reliability
If self-locking nuts are snap-fitted during screwing, then they are secured, but they can be loosened only with difficulty
Solution Approach 1:
The catch element's resilient nature creates a dynamic locking mechanism that adapts to the screwing process. During tightening, the catch elements flex to engage the grid firmly. For loosening, the same elasticity allows controlled disengagement when appropriate force is applied, enabling easier removal compared to rigid snap-fit designs while maintaining secure locking during operation.
5Reliability
If conventional self-locking nuts are used, then basic locking is achieved, but insufficient resolution of pre-stress and axial play adjustment is possible
Solution Approach 1:
The grid on the intermediate washer is segmented into multiple discrete positions around its circumference, and the catch elements can engage with different grid positions. This segmentation allows for fine adjustment of the nut's axial position and pre-stress levels by selecting specific engagement points, providing higher precision control compared to conventional self-locking nuts with limited adjustment 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
Enables easy production, precise adjustment, and high resolution of axial position and pre-stress, with the ability to securely lock and release the nut relative to the screw section, enhancing the screw connection's functionality.
Implementation Method 1
at least one catch that forms a positive lock with the grid, wherein the at least one catch is made of a sheet-metal component that is mounted resiliently and flexibly relative to a surface of the polygon
Data Source
AI summary
A screw connection having a screw section and a nut threaded thereon. A self-locking effect of the nut on the screw section is achieved in a simple manner in that an intermediate disk is supported non-rotatably on the screw section and is received on the nut so as to be rotatable relative to the nut. The intermediate disk includes a grid distributed around the circumference of the intermediate disk, and the nut carries at least one resiliently elastic, radially displaceable catch formed by a sheet-metal part which, after installing the nut, positively engages the grid to lock the nut against rotation relative to the screw section and intermediate disk. Upon application of a wrench to the nut, the at least one resilient, radially displaceable catch is compressed and drawn out of engagement with the grid, so that the nut can be rotated relative to the screw section.