Facade Panel Screw With Weakened Thread for Controlled Overtightening
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Solution Overview
Problem
Existing facade panel screws require multiple production steps, are costly, and lack versatility in handling and tool compatibility, often leading to over-tightening issues and material damage during installation.
Innovation Solution
A facade panel screw design featuring a weakened thread section and a narrow stop collar, allowing controlled overtightening and reduced torque absorption, which can be manufactured in a single operation and used with various setting tools, eliminating the need for additional processing steps and material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional screw design with full-strength threads throughout is used, then high back-tightening torque is achieved, but the screw cannot be safely overtightened and may damage the facade panel or substructure
Solution Approach 1:
The screw thread is segmented into two distinct sections: a first thread section with full strength for engaging the substructure, and a second thread section with reduced strength for controlled engagement with the facade panel. This segmentation allows the screw to provide high back-tightening torque while preventing damage through controlled thread failure in the weaker second section.
Solution Approach 2:
Different portions of the screw thread are given different mechanical properties. The first thread section has high strength characteristics for secure substructure engagement, while the second thread section has deliberately reduced strength to act as a safety mechanism. This local differentiation of quality resolves the contradiction between achieving high torque and preventing material damage.
2Manufacturing precision
If expensive multi-step production processes are used to manufacture facade screws with stop collars and threadless sections, then precise installation control is achieved, but manufacturing cost and complexity increase
Solution Approach 1:
The invention merges the functions of multiple separate components (stop collar, threadless section, and threaded section) into a single continuously threaded screw design. The thread transitions from full-strength to reduced-strength sections without requiring separate parts or additional manufacturing steps, thereby achieving precise installation control while simplifying the production process.
Solution Approach 2:
The screw design provides multiple functions within a single component: the first thread section engages the substructure, the second thread section engages the facade panel, and the transition between sections provides both a stop mechanism and torque limitation. This multi-functionality eliminates the need for separate stop collars and complex production processes.
3Reliability
If specialized setting tools with torque limitation are used, then over-tightening is prevented, but tool cost and operation complexity increase
Solution Approach 1:
The screw itself provides the torque limitation function through its differentiated thread sections. When the second, weaker thread section engages the facade panel, it naturally limits the torque that can be applied, preventing over-tightening without requiring specialized setting tools. This makes the system compatible with standard installation tools while maintaining reliability.
4Manufacturing precision
If pre-drilling of substructure is performed to improve screw pattern accuracy, then installation precision is improved, but installation time and process complexity increase
Solution Approach 1:
The screw design incorporates preliminary action by having the first strong thread section automatically engage and secure the substructure during the initial phase of installation. This eliminates the need for pre-drilling, as the screw creates its own secure attachment point while maintaining accurate screw patterning through the controlled engagement sequence.
Data Source
Figure 1~2
AI summary
A facade panel screw for the optimized fastening of facade panel elements to a substructure has a head with a very large diameter, a subsequent, essentially cylindrical shank section (22) extending along a central longitudinal axis (A), and a subsequent tip section (23). The shank section (22) in turn comprises, viewed from the head, a threadless underhead section (24), a stop collar (25), and a threaded section (28). The thread in a first subsection (26) of the threaded section (28) following the stop collar (25) has an outer diameter Dr, which, compared to the thread in a second subsection (27) with outer diameter Dn, is reduced over several thread turns, such that Dr < Dn. This threaded section 26 allows controlled overtightening of the facade panel screw during use.A corresponding fastening arrangement comprises a facade panel, a substructure for transferring the load to a building surface and a facade panel screw according to the invention.