Quick-Screwing Bush With Asymmetric Thread for High Pull-Out Strength
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing metal bushes for joining parts suffer from slow insertion speed and limited tensile strength, especially when used in low-density and/or small-thickness materials, and are difficult to produce and install efficiently.
Innovation Solution
A bush with a frustoconical hollow head and asymmetrical threading, featuring a wide angle of inclination for easy insertion and a small angle for high extraction resistance, combined with a polygonal profile for enhanced screwing and resistance, made of low-cost metal and produced via rolling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional metal bushes with standard threading are used, then the joining function is provided, but the insertion speed is slow and tensile strength is limited
Solution Approach 1:
The patent applies asymmetry by designing a threading profile where the engagement side has a larger angle (38°-42°) for rapid insertion, while the extraction side has a smaller angle (5.5°-8°) for high resistance to axial forces. This asymmetric geometry enables the bush to be quickly inserted while maintaining high tensile strength in low-density materials.
2Productivity
If conventional bushes are used for joining parts, then the joining function is achieved, but the installation time is excessive and production cost increases
Solution Approach 1:
The patent changes the geometric parameters of the threading profile, specifically the angles of the thread sides, to optimize both insertion speed and extraction resistance. The asymmetrical angles (38°-42° for engagement, 5.5°-8° for extraction) are carefully selected to achieve rapid installation while maintaining strength, and can be produced through standard rolling processes.
3Strength
If bushes are inserted in low-density and small-thickness materials, then the joining function is provided, but the tensile strength is insufficient with conventional designs
Solution Approach 1:
The asymmetric threading profile with a small extraction-side angle (5.5°-8°) creates high mechanical interlocking and friction resistance, enabling the bush to withstand axial extraction forces even in low-density or thin materials where conventional symmetric threading would fail.
4Ease of operation
If conventional threading profiles are used, then standardization is maintained, but the screwing speed and ease of insertion are reduced
Solution Approach 1:
By optimizing the threading angle parameters, particularly the engagement side angle (38°-42°), the patent achieves both easy screwing and rapid insertion. This parameter optimization allows the bush to be quickly installed with standard tools while maintaining ease of operation.
Data Source
Figure 1~4
AI summary
Bush comprising a substantially cylindrical hollow body (10); a substantially frustoconical hollow head (11), with an outer larger base (11a) and smaller base (11b) connected to the cylindrical body (10) by a crown (11c) inclined towards the longitudinal axis (X-X) of the bush body (10); a threading (12) formed on the outer side surface (10a) of the body (10); a female thread (13) formed on the inner side surface (10b) of the body (10); wherein the frustoconical head (11) has an inner cavity with a polygonal annular profile designed to form operating surface shaped for coupling with a corresponding tightening spanner.