Metal Bracelet Pin Assembly via Electron Beam Transparency Welding
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Solution Overview
Problem
Conventional methods for assembling metal bracelets with multiple rows of elements, such as force-fitting or gluing pins, often result in aesthetically unsatisfactory connections and detachment issues, and are costly when using screws or soldering.
Innovation Solution
The method involves creating axially offset blind bores with a flat bottom in outer elements for smooth pins, followed by electron beam transparency welding, which reduces air pockets and allows for a thin, easily removable weld bead, and includes a tumbling operation to eliminate burrs and clean metallic powders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pins are force fitted or glued or fixed by solder or laser into bores in outer elements, then the assembly is secure, but the aesthetic quality deteriorates and pins can become detached
Solution Approach 1:
The patent replaces mechanical fastening methods (force fitting, gluing, soldering, laser fixing) with electron beam transparency welding. This substitution creates an invisible joint that maintains aesthetic quality while ensuring secure pin retention, eliminating the detachment problems associated with mechanical methods.
Solution Approach 2:
The patent creates a vacuum environment during electron beam welding to prevent air bubbles from forming in the molten metal. This inert environment ensures clean, defect-free welds that are both aesthetically pleasing and mechanically reliable, resolving the contradiction between appearance and security.
2Strength
If transparency welding is carried out on pins in blind bores, then strong joints are formed, but air bubbles are created in the metal mass deforming the weld bead
Solution Approach 1:
The patent applies vacuum conditions during electron beam transparency welding to remove air from the blind bore environment. This prevents air bubbles from forming in the molten metal, eliminating defects in the weld bead while maintaining strong joint formation.
Solution Approach 2:
The patent performs preliminary actions to prepare the blind bore (creating appropriate diameter and flat bottom) before welding to facilitate air escape and prevent bubble formation during the welding process, thereby ensuring high weld quality.
3Ease of manufacture
If conventional bores are used for pin insertion, then assembly is simple, but air pockets remain at the bottom creating welding defects
Solution Approach 1:
The patent modifies the local geometry of the blind bore by creating a flat bottom instead of a conical shape. This local quality change allows air to escape during pin insertion and welding, preventing bubble formation while maintaining the simplicity of the assembly process.
Solution Approach 2:
The patent performs preliminary bore preparation with specific geometric characteristics (flat bottom, appropriate diameter) to enable air escape during subsequent operations, thereby preventing welding defects without complicating the manufacturing process.
4Strength
If electron beam welding is performed on outer elements, then strong transparent joints are achieved, but excess material is deposited requiring difficult machining
Solution Approach 1:
The patent performs preliminary preparation of the blind bore with a flat bottom and controlled diameter to regulate material deposition during electron beam welding. This ensures that excess material is minimal and easily removable, simplifying finishing operations while maintaining strong joints.
Solution Approach 2:
The patent controls welding parameters and bore geometry to minimize excess material deposition during electron beam welding. By optimizing these parameters, the weld bead becomes thin and regular, making finishing operations easy while preserving joint strength.
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
This method ensures a strong, aesthetically pleasing connection with minimal material loss and visible traces of welding, allowing for adjustable bracelets with reduced manufacturing costs and improved quality.
Implementation Method 1
the pins and the outer elements are transparency welded by carrying out a bombardment with an electron beam on the upper or lower wall of the outer elements
Implementation Method 2
the air trapped in the bore, after having driven in the pin, heats up and has a tendency to escape through the molten metal mass under the effect of the electron beam bombardment
Data Source
AI summary
The present invention relates to a method of assembling a metal bracelet (1) comprising two rows (2, 3) of outer elements assembled in pairs by pins (5) forming rigid links and at least one row (4) of intermediate elements mounted on the pins (5). The fixing of the pins (5) on the outer elements (2, 3) is carried out according to the following steps:on the inside lateral face of each outer element two blind bores with a flat bottom and of diameter greater than the diameter of the pins are produced,smooth pins are chosen and they are inserted in said bores, after the intermediate elements have been previously mounted on said pins,the pins and the outer elements are transparency welded by carrying out a bombardment with an electron beam on the upper or lower wall of the outer elements,a finishing operation is carried out on the bombarded surface in order to remove the weld bead.