Plastic Nut Clamping Structure for Repeated Stud Fastening
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Solution Overview
Problem
Existing fastening systems using plastic nuts for motor-vehicle body manufacturing face issues with maintaining sufficient clamping force over multiple detachments and reattachments, leading to potential self-detachment, wear, and quality standards not being met, especially under environmental influences and manual assembly errors.
Innovation Solution
A plastic nut with a radially elastic clamping device, comprising a clamping nose and a deformable hollow cylinder section, that maintains clamping force even after multiple screwing and unscrewing cycles by radially yielding and clamping onto the stud thread, preventing damage and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the plastic nut is screwed on and off multiple times, then the fastening and unfastening operation can be performed repeatedly, but the inner surface deforms and clamping force is lost
Solution Approach 1:
The plastic nut is divided into two functional segments: a reusable outer shell with the clamping device and a replaceable inner insert containing the threaded bore. After multiple operations, only the inner insert needs replacement while the outer shell remains, allowing repeated fastening operations without permanent degradation of the clamping function.
Solution Approach 2:
The inner insert is designed as a disposable component that can be easily replaced after deformation from multiple screwing operations. The valuable outer shell with clamping mechanism is recovered and reused with a new insert, separating the reusable structural elements from the consumable threaded component.
2Reliability
If a new plastic nut is applied after detaching, then sufficient clamping force is restored, but downtime increases due to nut replacement
Solution Approach 1:
By segmenting the nut into reusable outer shell and replaceable inner insert, the replacement operation becomes faster and simpler. Only the small inner insert needs to be exchanged rather than the entire nut assembly, reducing downtime while restoring clamping force.
Solution Approach 2:
The inner insert is pre-configured with the threaded bore and clamping features, allowing for rapid exchange without complex assembly operations. The pre-formed insert can be quickly installed into the outer shell, minimizing the time required to restore sufficient clamping force.
3Productivity
If automatic nut drivers are used for fastening, then productivity increases, but the exchange of plastic nuts causes long downtime
Solution Approach 1:
The segmented design allows the automatic nut driver to work with the outer shell while the inner insert is quickly swapped separately. This enables continuous operation where the driver maintains productivity while insert replacement causes minimal interruption.
Solution Approach 2:
The system enables dynamic operation where the reusable outer shell remains in the automatic driver for continuous fastening cycles, while only the small inner insert is dynamically exchanged when needed, maintaining high productivity with minimal downtime.
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 solution ensures a consistent and reliable clamping force is maintained, reducing downtime and meeting quality standards, even under environmental stressors and repeated use, without the need for frequent nut replacement or tool modifications.
Implementation Method 1
a radially elastic clamping device (22), comprising a clamping nose (26) and a deformable hollow cylinder section (28), that maintains clamping force even after multiple screwing and unscrewing cycles by radially yielding and clamping onto the stud thread
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Plastic nut (10) for multiple detachable fastening at a stud (12) protruding form a workpiece (20), comprising a base body (14) on which a cylindrical recess (16) penetrating through the base body (14) and a support surface (18) are formed. The base body (14) comprises in the cylindrical recess (16) an inner surface (44) for receiving a thread (52) of the stud (12). The plastic nut (10) comprises a clamping device (22), which is configured to provide a clamping force between the plastic nut (10) and the stud (12).