Screw Thread Deformation for Jamming and Assembly Control
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Solution Overview
Problem
Existing screw connections in clamps lack a simple and geometrically reproducible method to achieve a final assembly state, often requiring additional components that complicate assembly and may lead to unintended loosening due to thermal changes or vibrations.
Innovation Solution
Incorporating a geometrically determined deformation in the external thread, which collides with the internal thread flank, preventing further screwing and providing a secure jamming mechanism to prevent loosening, with features like radial indentation and galling for enhanced security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the screw is simply screwed into the mating thread element without additional components, then the assembly is simple, but the final assembly state cannot be geometrically defined and reproducible
Solution Approach 1:
A deformation is preliminarily created on the external thread at a predetermined distance from the screw head. This pre-formed deformation serves as a mechanical stop that defines the final assembly state when the screw is screwed into the mating thread element, eliminating the need for additional stop components while ensuring geometrically reproducible assembly.
2Manufacturing precision
If additional components like intermediate elements or stop elements are used to define the final assembly state, then the assembly state can be controlled, but the assembly becomes more complex
Solution Approach 1:
The function of additional stop components is extracted and integrated directly into the screw's external thread through a deformation. This eliminates the need for separate intermediate elements or stop elements, reducing assembly complexity while maintaining precise control over the final assembly state.
3Manufacturing precision
If the screw insertion movement is limited to a predetermined number of turns, then the final assembly state can be achieved, but thermal settling or vibrations can cause the screw connection to lose preload and loosen
Solution Approach 1:
A deformation is created on the external thread that preliminarily prevents reverse rotation and loosening. When the screw is screwed into the mating thread element, this deformation creates a mechanical interference that generates friction and potential galling, providing preliminary protection against thermal settling and vibration-induced loosening before such forces even act on the connection.
4Manufacturing precision
If a deformation is created on the external thread to define the final assembly state, then the final assembly state becomes geometrically reproducible, but the manufacturing process becomes more complex
Solution Approach 1:
The external thread geometry is modified by creating a localized deformation at a predetermined position. This parameter change in the thread geometry provides a mechanical stop that defines the final assembly state. The deformation can be created through various manufacturing methods such as plastic deformation, localized heating, or mechanical pressing, allowing flexibility in manufacturing process selection.
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
Ensures a precise and reproducible final assembly state with increased resistance to unintentional loosening, detectable by power tools, providing a secure and reliable screw connection.
Implementation Method 1
the deformation is rotated slightly further into the internal thread, resulting, in the simplest case, in a jamming effect between the screw and the mating thread element
Implementation Method 2
the external and internal threads are connected by galling at least in the area of deformation. This can have a positive effect in that unintentional loosening of the screw from the mating thread element is thereby prevented
Data Source
Figure 1~3
AI summary
The screw connection has a screw (6) having a screw head (8) and an external thread having a thread profile and a threaded shaft, where a counter-threaded element (7) has an internal thread adapted to the external thread. The external thread has a geometrically defined deformation at a predetermined distance to the screw head, where the deformation collides with one thread flank during the screwing of the screw in the counter-threaded element.