Concealed Metal Plate Joint for Wooden Table Legs and Tops
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Solution Overview
Problem
Existing methods for connecting a wooden panel to stands in furniture manufacturing are either labor-intensive, material-intensive, and aesthetically unpleasing, with visible metal edges and structural weaknesses due to recesses for metal plates.
Innovation Solution
A kit comprising metal plates with specific areas for screwing to both the stands and the panel, using screws with countersunk heads and blind holes with internal threads, along with positioning bolts, to create a stable and aesthetically concealed connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a frame structure is used to connect wooden panel and stands, then the connection is stable and strong, but the production becomes material and labor-intensive and the final product becomes bulky for transport
Solution Approach 1:
The frame structure is segmented into separate components (panel, stands, and connection elements) that can be manufactured independently and assembled later. The connection is achieved through individual metal plates attached to each stand, rather than constructing a complete frame around the panel, reducing material usage and assembly complexity while maintaining structural strength.
Solution Approach 2:
The essential connecting function is extracted from the bulky frame structure and concentrated into discrete metal plates that attach directly to the stands. This removes unnecessary structural elements while preserving the core function of connecting the panel to the stands, thereby reducing material consumption and simplifying production.
2Productivity
If metal plates are used to connect the wooden panel and stands, then the connection is simple and production is efficient, but the metal plate edges are visible from outside which reduces aesthetic impression
Solution Approach 1:
The metal plate is nested within a recess milled into the stand surface. The first area of the metal plate lies flush with the stand surface, while the second area protrudes inward into the recess, allowing the connection hardware to be concealed within the stand's structure rather than being externally visible.
Solution Approach 2:
The recess in the stand acts as an intermediary structure that hides the metal plate and connection elements. By creating a recess that accommodates the metal plate, the aesthetic appearance is preserved as the connection components are concealed within the recess rather than being exposed on the external surfaces.
3Shape
If the metal plate is sunk into the wooden panel and stand with recesses, then the connection is concealed aesthetically, but the wooden panel and stands are greatly weakened at these points
Solution Approach 1:
The recess is designed with specific dimensional characteristics (depth and cross-section) that are optimized for the particular stand and panel thicknesses. The recess accommodates the metal plate while minimizing material removal from critical structural areas. Reinforcement elements can be added locally at the recess location to compensate for the removed material and maintain structural strength.
Solution Approach 2:
The connection structure becomes a composite of wood (stand and panel), metal (plate and screws), and potentially reinforcement materials. This composite construction allows the recess to be aesthetically concealing while the metal plate and reinforcement elements provide the necessary structural strength to compensate for the material removed in creating the recess.
4Ease of manufacture
If blind holes are provided in wooden stands and panel for screws, then the connection is simplified, but the holding power may be insufficient compared to threaded inserts
Solution Approach 1:
The screw hole configuration offers different parameter options: simple blind holes for ease of manufacture, or blind holes with threaded inserts for enhanced reliability. The thread depth, insert material, and screw dimensions can be adjusted as parameters to achieve the desired balance between ease of assembly and connection reliability for different applications.
Data Source
Figure 1
Figure 2~3
AI summary
The connection is carried out by an assembly set of a metal board (1) with perforations (20), and a number of wooden screws (12) corresponding to a number of the perforations. The metal board is divided into two regions (3, 4). One of the regions amounts to an approximate cross-sectional area of a square cross-sectional table leg (2) in terms of a size and is screwed at the table leg. The other region projects above the cross-sectional area of the table leg and screwed at a lower side of a table board. Positioning and retaining bolts (13) are inserted in blind holes in the table board. An independent claim is also included for a table.