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I would like to be able to record the motion of the shafts on a loom. I have some mechanical end-stops, and would like to trigger them with levers that raise and lower when the treadles at the base of the loom are pressed. I have access to a 3d printer to build a mechanism with which to trigger the endstops.

I don't want to attach anything permanently to the loom, but need a way to reliably push the end-stops, even if the lever doesn't go all the way up. What type of mechanism would work well for this?

I have tried to model a type of array of hinges with long "keys" extending outwards from the hinge. The end-stop is not pictured in my model, but would be mounted to the translucent surface. Each key has a raised tooth which would strike the end-stop when raised. Is there a better option?

3d cad render of my current idea

end-stop loom

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  • $\begingroup$ "Actuate a mechanical end-stop" is a bit confusing. An end-stop can't be actuated. It's just a stop. Do you mean that you want to detect when the lever reaches or gets close to the end-stop? $\endgroup$
    – Transistor
    Commented Nov 17, 2023 at 2:49
  • $\begingroup$ @Transistor What I mean is depress it. In the picture you will see what type of end-stop I mean. There is a small metal lever that can be "clicked". I would like the up-and-down motion of the shafts, which are pulled up by levers attached to chains, to trigger the end-stop in some fashion. My apologies if I have misused the word; English is not my first language. $\endgroup$ Commented Nov 17, 2023 at 2:57
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    $\begingroup$ it is unclear what you are trying to detect ... please draw an arrow in the picture that points to the endstop $\endgroup$
    – jsotola
    Commented Nov 17, 2023 at 5:26
  • $\begingroup$ @jsotola The lifting of each of the six hinges as pictured. The end-stop which is to be triggered is not pictured but would be mounted with screws to the translucent plane, and the tooth protruding from each key, or hinge, would strike the small metal lever attached to the limit switch. It seems like it would be more appropriate to fashion a cam of sorts to the hinge mechanism instead, which was what I was trying to find out. $\endgroup$ Commented Nov 17, 2023 at 17:05
  • $\begingroup$ We need more pictures of the loom. Have you considered a hall effect switch and magnet? That's usually the easiest method for ends stops. $\endgroup$
    – Drew
    Commented Dec 19, 2023 at 15:31

2 Answers 2

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After reading a bit about engineering, it seems like a better choice would be a cam mechanism along the pivot point of the hinge, which, when lifted by the loom lever, would activate the mechanical end-stop as pictured.

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Levers are tricky to set up just the way you want. You might be better with a cable. You have one end of the cable attached to the treadle, run it with a couple of pulleys to alongside the switch, attach a cylinder on the cable which will operate the switch as the cable moves and attach the other end of the cable to a return spring which is secured.
Actually you could use a bicycle brake cable and do away with the pulleys. Plus nothing will interfere with it. With this setup you can arrange it so that the cylinder operates the switch either when the treadle goes down or when it goes up.
Hope that's a clear description.
As you have a 3D printer, you could have the cable directly operate a small lever to close the switch. Just put a light spring on the end of the cable to prevent excess stress.

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