# Do you know any mechanism that can pass a thread through several holes?

Well i am stuck trying to figure out this problem, actulally i see a machine that can make it with a torus, a torus coilling machine. But that not work with a multi turus shape.

I want to automate something like this:

• How do sewing machines do buttons? They have 4 holes... Commented Nov 17, 2020 at 2:13
• This is how a sewing machine works. Pushes down catches pulls up. Commented Nov 17, 2020 at 6:59
• but sewing machine use 2 threads for do that. Commented Nov 17, 2020 at 17:57

I've never seen a machine do this, but consider this.

1. Tie the thread to the middle of rod and have the rod in a vertical orientation.
2. Have two jaw like, or pincer like devices, one vertically above the other. Place the rod, with thread attached, into the one of the sets of jaws, say the top one.
3. As the chain of toruses moves laterally the top jaw moves vertically downwards threading the rod and thread through the hole of a torus.
4. The bottom of the rod is then grasped by the bottom set of jaws. When the top of the rod is below the chain of toruses the chain of toruses moves a set distance to align the next hole with the two sets of jaws.
5. The bottom jaws move in an upward direction to pass the rod to the upper jaws and the process continues.

I've recently seen a video in which chain link fence is being manufactured. The individual segments of fence are somewhat "corkscrewed" into the existing assembled fence.

One method I can envision to accomplish your goal is to have a helix (three-dimensional constant diameter spiral) that is threaded into the multi-torus shape until the entire length is captured by the helix. The end of the helix would then capture the thread and unwind itself, pulling the thread to the entry point.

It would be necessary to have a swivel on the end of the helix or to spin the thread source to match the unwinding helix. The former is more likely to snag, while the latter is mechanically more complex.