Two-Diameter Dowel Screw for Stable Furniture Panel Joints
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Solution Overview
Problem
Existing fasteners for connecting wooden panels in furniture construction, such as Sped Pano screws, face challenges with angular stability, material displacement during assembly, and require additional dowel preparation, leading to increased assembly effort and potential damage.
Innovation Solution
A dowel screw with a cylindrical tip, a threaded shank, and a two-part thread-free lower head section with varying diameters, designed to act as a dowel in both plates, ensuring angular stability and minimizing material displacement, allowing for easier assembly without additional dowel preparation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If self-drilling screws are used with large diameter to improve holding forces, then the holding strength is improved, but the screw cannot be used in thick fiberboard due to material displacement and drilling limitations
Solution Approach 1:
The screw is divided into distinct functional segments: a threadless dowel portion for precise alignment and positioning in the first panel, and a threaded portion for secure engagement in the second panel. This segmentation allows each portion to perform its specific function optimally without interfering with the other, enabling effective use in thick fiberboard materials.
Solution Approach 2:
The threadless dowel portion performs preliminary alignment and positioning actions before the threaded portion engages. By pre-establishing the correct position and orientation through the dowel section, the subsequent threading operation occurs with minimal material displacement and without requiring aggressive self-drilling that would be limited by material thickness.
2Ease of operation
If Sped Pano screws with single dowel section are used, then assembly is simplified, but angular stability is insufficient compared to dual-dowel alignment systems
Solution Approach 1:
The alignment function is segmented into two distinct dowel portions located at different ends of the screw. This dual-dowel segmentation provides angular stability from both the first and second panels simultaneously, achieving precision comparable to traditional alignment dowel systems while maintaining the simplicity of a single fastener component.
Solution Approach 2:
The alignment dowel function and the fastening screw function are merged into a single integrated component. The threadless dowel portions at both ends provide alignment stability, while the central threaded portion provides fastening, combining multiple functions that would traditionally require separate alignment dowels and screws into one unified fastener.
3Measurement precision
If traditional alignment dowels are used with Sped Pano screws, then precise angular alignment is achieved, but additional pre-drilling and assembly steps are required
Solution Approach 1:
The alignment dowels and fastening screw are merged into a single integrated component. The dual threadless dowel portions embedded in the screw body provide the alignment function that would traditionally require separate dowel elements, eliminating the need for additional pre-drilling operations and reducing the number of assembly steps.
Solution Approach 2:
The single fastener component performs multiple functions: the threadless dowel portions provide alignment and positioning, while the threaded portion provides fastening and securing. This multi-functionality eliminates the need for separate alignment dowels and simplifies the overall assembly process while maintaining precise angular alignment.
4Stability of the object's composition
If screws engage deeply in cover plate to provide dowel effect, then angular stability is improved, but material displacement and potential damage to panels increase
Solution Approach 1:
The screw structure is segmented into threadless dowel portions that engage without cutting or displacing material, and a threaded portion that provides secure engagement. This segmentation allows the dowel sections to establish precise positioning and angular stability through friction and fit alone, without the harmful material displacement associated with threading operations.
Solution Approach 2:
The threadless dowel portions perform preliminary positioning and alignment actions before the threaded portion engages. By establishing the correct position and angular orientation through the dowel sections first, the subsequent threading operation occurs with minimal additional material displacement and without causing damage to the panel surfaces.
Data Source
Figure 1~2
Figure 3~4
AI summary
A dowel screw, particularly for furniture construction for corner connections of panel-shaped components to chipboard or hardboard, has a substantially cylindrical structure of length L, with a tip (110), a threaded shank section (120) adjoining it, a threadless underhead section (130) adjoining it, and a head (140) with a force-applying point. The threadless underhead section has at least two subsections (131, 132) with different diameters d1, d2. These are referred to as the first subsection near the head (131) and the second subsection near the thread, wherein the first subsection (131) near the head has a larger diameter d1 than the diameter d2 of the second subsection (132). The use of such a dowel screw and a component arrangement with a corner connection between a top and an end panel using such a dowel screw are also described.