Segmented Centering Sleeve for Precise Facade Screw Assembly
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Solution Overview
Problem
Existing fastening technologies for facade elements face challenges in achieving precise and centered screw positioning due to thermal expansion differences between facade elements and substructures, leading to material fatigue and assembly issues such as tilting or displacing screws, which can disrupt the facade image and prevent effective stress absorption.
Innovation Solution
A centering sleeve composed of multiple sleeve elements connected by a separable connection bracket, designed for one-time use, is inserted into the facade element hole to provide centering and guidance during screw assembly, with flange-like overhangs acting as stops and driver elements engaging the screw thread, ensuring accurate placement and subsequent ejection without remaining components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If oversized holes are used in facade elements to accommodate thermal expansion, then play in the fastening plane is achieved, but the screw cannot be properly guided and may tilt or displace during assembly
Solution Approach 1:
A centering sleeve is introduced as an intermediary component between the oversized hole in the facade element and the screw. The sleeve has an inner diameter that guides the screw precisely while its outer diameter fits within the oversized hole, allowing thermal expansion play to be maintained without compromising screw positioning accuracy
Solution Approach 2:
The centering sleeve is designed as a disposable component that is inserted into the oversized hole, guides the screw during assembly, and then remains in place as a permanent part of the fastening system, eliminating the need for complex reusable centering mechanisms
2Ease of manufacture
If self-drilling or self-cutting screws are used to avoid pre-drilling the substructure, then cost is reduced, but assembly time increases and screw tilting is more likely
Solution Approach 1:
The centering sleeve is pre-inserted into the hole in the facade element before the screw assembly process begins. This preliminary action establishes precise centering and guidance paths, allowing self-drilling screws to operate more efficiently without tilting or wandering, thereby reducing overall assembly time
3Manufacturing precision
If a solid centering sleeve is used to guide the screw, then centering precision is improved, but the sleeve may deform or be damaged during the screwing process
Solution Approach 1:
The centering sleeve is divided into multiple segments or elements that are connected by separable connection brackets. This segmentation allows the sleeve to flex and adapt during the screwing process, distributing stresses and preventing deformation or damage while maintaining centering precision
Solution Approach 2:
The separable connection brackets allow the sleeve elements to move relative to each other during assembly, transforming the sleeve from a rigid structure to a dynamic, adaptive component that can accommodate assembly variations without compromising integrity
Data Source
AI summary
A sleeve (20) for centering fasteners during the assembly of components such as facade elements on the substructure of a building envelope includes a sleeve body (23) and a connection bracket (25). The sleeve body (23) has a plurality of sleeve elements (21, 22) which are grouped around a central center axis A and are spaced apart from each other by gaps running in the sleeve longitudinal direction. At least a first (21) and a second (22) sleeve piece are connected to each other at an axial longitudinal end of the sleeve body (23) by a separable connection bracket (25), preferably the connection bracket is separable via predetermined breaking points. Such a sleeve is used in the construction of facades, wherein it is inserted into a pilot hole of a facade element, the connection bracket is broken off and a fastener is inserted into the sleeve. Driving the fastener centers the fastener in the sleeve and the sleeve is removed from the pilot hole.