Angle Bar Fastening Groove Structure for Tool-Free Shelf Assembly
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Solution Overview
Problem
Existing angle bar structures for shelf assembly either require tools for assembly, compromise on ornamental appearance due to protruding bolts, or have weak binding forces due to small contact areas, leading to noise and instability during assembly.
Innovation Solution
An angle bar design featuring a vertical frame with sequentially formed fastening grooves of varying widths and a horizontal frame with inclined fastening protrusions, eliminating the need for bolts and nuts, enhancing ornamental appearance, and increasing binding strength through precise fitting without requiring tools or hammering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a bolt and nut are used to combine vertical and horizontal angle bars, then the connection strength is improved, but the ornamental appearance deteriorates due to outward protruding bolt heads
Solution Approach 1:
The protruding bolt head is extracted/removed from the design. Instead of using a conventional bolt with an external head, the invention uses a rivet that is inserted into a hooking groove and flattened to create a hidden fastening system. The fastening mechanism is taken inside the structure (into the groove) rather than remaining external, thus maintaining connection strength while eliminating the unsightly protruding head.
2Shape
If a rivet is inserted into a hooking groove for fastening, then the ornamental appearance is improved, but the binding force strength deteriorates due to small contact areas
Solution Approach 1:
The contact area is extended from a single-point or small-surface contact to a multi-dimensional engagement. The rivet not only contacts the bottom of the groove but also engages with the inclined surfaces on both sides. When flattened, the rivet creates contact across the entire groove cross-section, utilizing multiple dimensions (width, depth, and inclination surfaces) to maximize the effective contact area and thus the binding force.
3Reliability
If a convex portion is forced into a fastening groove by hammering, then the assembly is secured, but noise is generated during the assembly process
Solution Approach 1:
The rivet is pre-formed with an inclined surface that matches the groove's inclination before insertion. This preliminary preparation of the rivet geometry allows it to slide smoothly into the groove without requiring forceful hammering. The inclined surfaces are pre-configured to guide the rivet into place, eliminating the need for impact assembly and thus preventing noise generation.
4Reliability
If conventional fastening methods are used, then assembly security is achieved, but tool requirements increase complexity
Solution Approach 1:
The rivet and groove are designed to work together as a self-contained fastening system. The rivet's inclined surface matches the groove's inclination, allowing the components to self-align and self-secure during insertion. The system is designed to be self-sufficient, requiring no external tools (screwdrivers, drills, hammers) to achieve secure assembly. The geometry itself provides the fastening mechanism, making the system self-service and tool-free.
Data Source
AI summary
Provided is an angle bar for shelf assembly, the angle bar including a vertical frame in which a plurality of fastening grooves is formed and a horizontal frame on which a fastening protrusion is formed, wherein the plurality of fastening grooves, each including upper and lower grooves, are formed, the lower groove has a narrower width than the upper groove, and is connected to the upper groove with an inclination portion in between, wherein the fastening protrusion includes a convex portion having an inclination surface and first and second wing portions that are formed on lateral surfaces, respectively, of the convex portion, and wherein a distance between respective end portions of the first and second wing portions is smaller than a width of the upper groove and is larger than a width of the lower groove, and the convex portion has a wider width than the lower groove.