Hi all,
I‘m looking into creating my first "serious", but still relatively small project in the form of a cordon control. The end goal is to have a device which can be controlled via an rf remote for lowering and raising the chain by winding/unwinding it.
But of course I want to tackle it step by step and the first one would be to build a simple prototype and for it find a fitting engine and gear for winding the chain.
I was thinking about going with a worm gear, as potentially this should hold the chain in place when it is raised, in combination with a stepper motor (although I‘m not sure if it will be powerful and fast enough).
Does that make sense, or can you suggest better hardware for the job?
How large are the links in the chain and how flexible will the chain be? Will the chain wrapping be controlled so there is no overlap, making layers of chain?
Why wind the chain, rather than just pulling like a chain hoist?
jremington (can only mention two users in a single post, sorry!)
Thanks for the link, I will take a look there!
@groundFungus
Thanks for the explanation! I was under the impression, that a stepper motor could be enough (although it is supposed to be cheaper which is a good point for a prototype/testing).
Also thanks for the link to the gearmotors! Maybe I missed it, but I can‘t find any info there about the used gear and as far as I know not all gear types will hold position without current.
@Paul_KD7HB
Thanks for your response!
Tbh, I haven‘t measured this out yet, but I will give you the details later.
Basically the idea was to build a sheet metal case which is roughly as wide as the shaft of the motor is long, so that I can put it in completely and that the walls of the box are a limiter for the chain.
Thus when the chain gets winded up it will make layers.
Chain hoist is a very good point, that I also thought about at first, but I couldn‘t find an "out of the box" option (like with a worm gear) about how to keep the chain in place. All I found involved adding at least an additional motor for controlling a part that holds the whole device in position, like a "position screw". And as this really is my first more serious project (escape from from tutorial hell), I wanted to keep it as simple as possible and winding/unwinding at least sounded easier as it is needs less parts.
The next problem was, that for such a hoisting mechanism I likely would need two chain poles, that work in sync, so that I can lower it properly on both ends. It might be low enough on the other side even if I only go for a single pole, but because of the issue about keeping it in position I didn‘t really looked much more into it.
However I‘m all ears about that idea, so if you have more input about it, it would be great!
That is correct. A worm drive will be very resistant to being back driven. Spur gear trains are not as resistant as worm drive and their resistance is proportional to the ratio. A 100:1 gear box will be much more difficult to back drive than a 10:1 gear train.