Expansion-Sleeve Doubling Fitting for Tool-Free Panel Anchoring
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Solution Overview
Problem
Existing double fittings for furniture panels require the use of an impact tool to anchor the fitting housing in a blind hole, making installation cumbersome and tool-dependent.
Innovation Solution
A double fitting with an expansion sleeve and inner ring that allows radial expansion of tabs, enabling manual insertion and anchoring without tools, using a threaded bolt and sleeve nut for two-dimensional adjustment and fixation of panels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ring-shaped fitting housing is driven into a blind hole using a hammer or driving tool, then the fitting housing is firmly anchored in the blind hole, but the installation process becomes tool-dependent and cumbersome
Solution Approach 1:
The expansion tabs are designed to be radially expandable, transitioning from a collapsed state during insertion to an expanded state for anchoring. This dynamic transformation allows the fitting to be installed without tools, then securely anchored through expansion, resolving the contradiction between easy installation and reliable anchoring
Solution Approach 2:
The radial dimension of the expansion tabs is changed from a compressed state (smaller than the blind hole diameter) to an expanded state (larger than the blind hole diameter). This parameter change enables tool-free insertion followed by secure anchoring, eliminating the need for hammering while ensuring reliable fixation
2Adaptability or versatility
If the clear opening diameter of the fitting housing is larger than the bolt diameter, then two-dimensional adjustment of the front panel is enabled, but the fitting housing cannot be manually inserted into the blind hole
Solution Approach 1:
The fitting housing is segmented into a body and radially expandable tabs. During insertion, the tabs are compressed to reduce the effective diameter, allowing manual insertion through the blind hole. After insertion, the tabs expand to provide both anchoring and adjustment capability, resolving the contradiction between adjustability and insertion ease
Solution Approach 2:
The expansion tabs provide dynamic dimensionality - compressed during insertion to enable manual placement, then expanded to provide the clear opening needed for panel adjustment. This dynamic transformation resolves the contradiction between requiring a large opening for adjustment and needing a small profile for easy insertion
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
Facilitates easy and tool-free installation of double fittings, allowing for two-dimensional adjustment and secure fixation of panels with reduced complexity and increased user convenience.
Implementation Method 1
at least one expansion tab is expanded by the inner ring, thereby anchoring the expansion sleeve in the hole
Implementation Method 2
The at least one expansion tab and/or the outer side of the inner ring, viewed in the tightening direction, extend obliquely or conically radially inwards in order to expand the at least one expansion tab radially outwards by pulling the inner ring towards it
Data Source
Figure 1a~1b
Figure 2
AI summary
The invention relates to a doubling-up fitting (1), comprising: - an expansion sleeve (2), which has a sleeve bottom (3) with a sleeve bottom opening (4) and has at least one expansion tab (5), which expansion tab can be spread radially outward; - an inner ring (6), which can be axially slid in the expansion sleeve (2) toward the sleeve bottom (3) in a tightening direction (7) in order to spread the at least one expansion tab (5) radially outward; - a threaded bolt (8) with a screw thread (9) and with a bolt head (10), which engages behind the inner ring (6) in the tightening direction (7); and - a threaded part (11) having a widened head (12), which threaded part can be screwed together with the screw thread (9) of the threaded bolt (8); wherein the opening diameter (d1) of the sleeve bottom opening (4) and the clear opening diameter (d2) of the inner ring (6) are each greater than the bolt diameter (D) of the threaded bolt (8).