Metal Strip End Joining via Transversal Eyelets
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Solution Overview
Problem
Existing methods for joining metal sheet ends in machining systems are inefficient, as they either result in rigid sections that cannot pass through all systems or require complex and costly processes, and do not provide a flat, edge-free joint resistant to high tensile loads, chemical attacks, and high temperatures, especially when dealing with different materials or difficult-to-work metals.
Innovation Solution
A method and device that punch multiple eyelets transversally across the metal sheet ends in one stroke and then press them into place in a second stroke using a work tool with alternating punching and pressing tools, allowing for rapid and inexpensive joining with a shared drive, and a clamping system to secure the sheets during the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If interlocking connections with cruciform cuts and flanging are used to join strip ends, then the joint strength is improved, but the strip sections become rigid and cannot pass through all systems
Solution Approach 1:
The joining process is segmented into two distinct strokes: first punching holes through the overlapping strip ends, then pressing eyelets into those holes. This segmentation allows the creation of a strong joint without requiring complex interlocking structures that would rigidify the strip sections.
Solution Approach 2:
Eyelets serve as intermediary elements that facilitate the joining of strip ends. These eyelets are punched through both strips and then pressed into place, creating a strong connection without requiring the strips themselves to form rigid interlocking structures.
2Stability of the object's composition
If ring-shaped welded joints are provided at a distance from strip ends to create stability, then the joint stability is improved, but the process becomes more complex and costly
Solution Approach 1:
The solution extracts the joining function from complex welded processes and simplifies it to a mechanical eyelet insertion process. By removing the need for welding equipment and complex positioning systems, the device complexity is reduced while maintaining joint stability through the eyelet-hole connection.
Solution Approach 2:
The joining method changes from thermal welding to mechanical insertion, altering the fundamental parameter of the joining process. This parameter change simplifies the equipment needed while achieving stable joints through the mechanical interlock of eyelets in punched holes.
3Productivity
If electric welding with electrodes and voltage is used to join thin foil sheet ends, then the joining speed is improved, but the joint becomes susceptible to chemical attacks and high temperatures
Solution Approach 1:
The eyelets function as disposable mechanical fasteners that are inserted and immediately provide the joining function. Unlike welds that create permanent but chemically vulnerable bonds, the mechanical eyelet connection resists chemical attacks and high temperatures without degrading, while maintaining rapid joining speed.
4Manufacturing precision
If multiple holes are punched and eyelets are pressed in separate operations, then the manufacturing precision is improved, but the joining time increases
Solution Approach 1:
The punching and eyelet pressing operations are merged into a single two-stroke process. The first stroke punches all holes simultaneously, and the second stroke presses all eyelets into place simultaneously. This merging maintains high precision through proper tooling while minimizing total joining time compared to sequential operations.
Solution Approach 2:
All holes are punched in advance during the first stroke before the eyelet pressing begins. This preliminary action ensures precise hole positioning is established before the eyelets are inserted, allowing the second stroke to focus solely on pressing the eyelets into the pre-positioned holes without compromising precision or adding significant time.
Data Source
AI summary
A method and a device are provided for joining the ends of strips with two or more surfaces arranged flat on top of each other, more particularly metal sheets that can be coiled, in order to draw these successively through a treatment or machining system. It is provided that the strip ends are joined by means of a plurality of eyelets arranged essentially transversally to the strip direction, wherein initially all holes are simultaneously punched in a first stroke and then all eyelets are pressed in a second stroke. The device has a clamping device and a machining unit, which has a working tool with a plurality of punching and pressing tools, wherein the working tool and a die are displaceable by the distance between two neighboring individual tools and wherein above the punching and pressing tools, a pressing device is provided.