How to use a printer stepper DC motor to make a 'lift'

Other Hardware Motors, Mechanics, Power and CNC
1

Hi.
I like to reuse things, and I have a lot of stepper motors taken from old printers. They look good and strong enough to automate a thing like this:

It is a method to use upper space to let dressed drying.
What puzzles me is that even if I use one or two of the motors, they are 'loose', in the sense that when you stop giving current, the shaft is free to roll, so everything would fall down...
Do you know any mechanism to avoid this problem?
Thanks in advance,
Andrea

2

they are 'loose', in the sense that when you stop giving current, the shaft is free to roll,

Yes that is how all stepping motors work.

Do you know any mechanism to avoid this problem?

A ratchet?

3

A ratchet or shaft lock operated by another motor?

4

they are 'loose', in the sense that when you stop giving current, the shaft is free to roll,
Yes that is how all stepping motors work.

Stepper motors require power to maintain positions when stopped.

5

Thanks!
Yes, I already thought about a ratchet, but:

  • I don't know where to find one;
  • I don't know where to buy one;
  • I don't know if it's easy to unlock, when I have to reverse the movement (I lift up, but then I need to take it down too! :slight_smile: )
    Andrea
6

if you cant use autocad then i honestly have no idea where to get a ratchet but.....

1440×1080 85.8 KB

using something like the release mechanism in the picture but instead of a shaft ratchet use a ratchet gear
(really any gear will work as long as your release systems teeth match)
that is the simplest way i can think of

7

I don't know where to find one;

Try google. as we have no idea where you live any advice would be useless.

I don't know where to buy one;

Try google. as we have no idea where you live any advice would be useless.

I don't know if it's easy to unlock, when I have to reverse the movement (I lift up, but then I need to take it down too!

Then why did you not mention all that in your original question? Given this new information that you knew all about ratchets in the first place you have to admit it was quite a poor attempt at asking a question.

I hesitate to offer any more suggestions as you might already know them but how about a lever that holds the ratchet open controlled by a solenoid.

8

Yes, I realize that all of you are by far more experienced than me, and that my question was really generic...
Probably I'm not the ideal user of this forum... :frowning:
Andrea

9

I suggested in another forum that a servo might be a convenient way to make a brake for when the stepper is depowered. It would be easy to move the brake on and off. With a bit of clever positionong the servo would not need power to keep the brake on.

...R

10

This is a classic case where a standard DC motor and worm-gear would be appropriate,
the worm gear holds through friction when the power is removed and you only
have end-positions to detect, so no need for anything more sophisticated in positioning.

Most cheap linear actuators are this principle, often using a lead-screw rather than worm
gear.

11

A stepping motor from a printer will not be able to lift such a thing anyway. Sure it might lift it when it is empty but when it is full of clothes, and wet ones at that, then you don't have enough torque so you will need some sort of gearing anyway.