Blind Stud Insert with Crimped Anchor and Knurling
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Solution Overview
Problem
Existing methods for manufacturing and assembling blind stud inserts are time-consuming due to processes like roll-tapping and spinning, and they often suffer from poor stud retention and potential separation under torque or axial forces, especially when cross-threading occurs or during disassembly.
Innovation Solution
A blind stud insert design featuring an anchor stud with opposing angled knurling and annular grooves, made of dual-phase steel, which is crimped into a body, providing strong adhesion and resistance to torque and axial forces, eliminating the need for heat treatment and reducing assembly steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If roll-tapping and spinning processes are used to assemble the insert, then the threaded connection is achieved, but the assembly time increases significantly
Solution Approach 1:
The invention extracts the threading operation from the assembly process by providing pre-threaded components (body and anchor stud) that are manufactured separately with their threads already formed. This eliminates the time-consuming roll-tapping step during assembly, allowing for rapid insertion and crimping while maintaining reliable threaded connection strength through the pre-formed threads.
Solution Approach 2:
The threads on both the body and anchor stud are formed in advance during manufacturing rather than during assembly. This preliminary action ensures that the threading operation is completed with optimized processes before assembly, enabling faster and more reliable assembly through simple insertion and crimping operations.
2Strength
If the anchor stud is heat treated to increase hardness, then the threaded shank can withstand staking force, but the production complexity and time increase
Solution Approach 1:
The invention changes the material parameter by specifying that the anchor stud be made from steel with a minimum tensile strength of 1000 MPa and elongation of 10%. This high-strength material selection provides the necessary hardness and strength to withstand staking and crimping forces without requiring additional heat treatment processes, thereby simplifying the production process while maintaining required strength properties.
3Reliability
If cross-threading occurs between body and anchor stud, then assembly time increases to correct the error, but if proper threading is ensured, then assembly precision must be maintained
Solution Approach 1:
The invention provides beforehand cushioning against cross-threading by designing the threads on both the body and anchor stud with matching tolerances and geometries that ensure proper engagement. The pre-formed threads are manufactured with controlled precision to prevent cross-threading during assembly, eliminating the need for time-consuming corrections while maintaining reliable thread engagement.
4Ease of manufacture
If the body is unthreaded and staked directly onto the anchor stud, then assembly is simpler, but stud retention is poor
Solution Approach 1:
The invention segments the retention mechanism into two distinct functions: the threaded connection provides primary retention through screw-thread engagement between the body and anchor stud, while the crimping operation provides secondary mechanical interlocking. This segmentation allows the threaded portion to ensure strong retention while the crimped portion provides additional mechanical anchoring, achieving both assembly simplicity and high retention reliability.
5Ease of operation
If high torque is applied to the insert, then the fastener can be installed, but the body and anchor stud may separate
Solution Approach 1:
The invention merges two retention mechanisms: the threaded connection between body and anchor stud provides rotational resistance during torque application, while the crimped mechanical interlock provides axial bonding strength. This combination ensures that high torque during fastener installation does not cause separation, as both the threaded engagement and crimped connection work together to resist the applied forces.
6Ease of repair
If the insert is removed from the workpiece for recycling, then the workpiece can be disassembled, but the anchor stud and body may separate during removal
Solution Approach 1:
The merged retention system of threaded engagement and crimped mechanical interlocking ensures that the body and anchor stud remain securely connected during removal operations. The threaded connection resists rotational forces while the crimped portion resists axial separation forces, allowing the entire insert assembly to be removed as one unit from the workpiece for recycling without internal separation.
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 insert assembly is simplified, with improved stud retention and resistance to torque and axial forces, reducing the likelihood of separation and maintaining corrosion-resistant coatings, while enabling efficient installation and removal without compromising torsional strength.
Implementation Method 1
at least two areas of opposing angled knurling... material is caused to enter the interstices of the anchor stud knurling, thus firmly holding the body onto the anchor stud
Implementation Method 2
The provision of two areas of knurling enables the insert to cope with such torque in either direction
Implementation Method 3
crimping an unthreaded body onto an anchor stud... material of the body is forced into the interstices of the knurls
Data Source
AI summary
An insert for blind installation in a workpiece, and method of manufacture of an insert, the insert (2) comprising a body (4) and anchor stud (6); wherein the stud is inserted into a through bore (22) in the body, part of the stud extending beyond the end of the through bore, and a part of the stud provided with opposed areas of knurling (14, 16) such as threading, being enveloped by a reduced diameter section (24) of the body, such that crimping the stud onto the body causes material to enter the knurling, thereby firmly attaching body and stud, allowing the insert to withstand high torque.