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DIY paper beltdrive design/build Answered

I'm looking for examples of home-made paper feed / belt drive mechanism - not having any success! Hoping maybe someone has seen or done something similar that I can learn from.

The idea is that I have a loop of paper that needs to scroll continuously past a window. The gadget has to fit inside a shoebox (roughly), so I'm not about to take apart some old printers, an old movie projector or a belt sander.

Seems to me I need a small motor and some rubber spindles/rollers mounted to a frame. Not so different to a belt sander. But much lower RPM, and HP!

So, have you seen any designs that resemble this sort of thing? A DIY belt drive that will run off AA/9v batteries?

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Downunder35m
Downunder35m

1 year ago

Don't know why I never noticed it before but your request made me spot a bus shelter with revolving advertisements.
Basically the same principle, just with a long foil that rolls up and down from either roller.
With not much else than tinkering to do in isolation I took the liberty to go through my old scrap boxes with motors....

Syncronous motors popped up a few times, including one from a microwave - the one turning the plate.
The are free to get from a dead or discarded microwave, have a slow sped gear box and relatively high torque for this low speed.
Only problem is that you might have to get a few or modify one to only work in one direction - if the direction matters for your application.
For some reason most of these motors reverse the direction after every stop.
it is possible to remove the part that changes the direction though.
Another motor that popped out of my box was used in some cheap toy - the ones for these jumping dogs.
Simple 3V DC motor, so maybe better than the microwave one for mains power.
It is a rather fast spinning motor with a worm drive for reduction.
AndI had no problems finding similar ones online by using "3V toy motor gear" in the search - different speeds, voltage requirements, torque...

The paper problem...
I have to say that using the roller from old toner cartridge or dicarded printer would be the easiest solution :(
Creating a simple sring loaded tension system for the rollers is easy, however I noticed the problem of alignment...
Both roller need to be 100% parallel AND the paper drum needs to be perfect - otherwise the paper will roll off to the side.
On things like belt sanders this centering is performed by the slightly "egg shaped" roller.
The belt is forced to run out of alignment as it always tries to run off this roller.
But when it does it als twists slightly and that causes the opposte effect on the other roller.
As a result the belt has no other option but to wobble centered.
I tried with two parallel rollers that I turned by hand - stright ones like found in a printer.
It seems to be possible to keep a paper drum centered if the tension is provided by a fulcrum mechanism.
Meaning the roller has a central mount for the spring and from there a triangle goes to the ends.
Whenever the pressure or tension on one side gets too high the roller tilts slightly.
IMHO too complicated to construct and not reliable enough with normal paper.
Then I cleaned our bun toaster at work, which is also belt driven.
And that one might have provided a feasable solution to keep your problem simple and cheap to solve :)
The centering and required force on this toaster is NOT provided by the rollers grabbing the sheet.
Instead the sheet has a fabric strip either side wth buttons in it - the exact same time you find in clothing.
You know, these little metal dots that you press together and pop apart? ;)
If not check in very nice underwear for females ;)
On the roller there are rims for these strips with holes at matching distance for these bottons.
No chance to ever go out of sync or wander off center.
On a small scale it should be possible to do it the other way around to make it much simpler.
How I would do it:
Create or find a roller of suitable diameter - I would not go below 4cm in diameter, preferably though at least 10, you see soon why ;)
You need the pins or cones on the roller to transport the paper and to hold it in place.
If you have a 3D printer this is an easy fix, without it though...
I would try PVC piping.
Find the exact radius/diameter of the pipe and create an angular template for the markings.
One way of doing this with the option for error is to wrap some paper around the pipe, mark where it matches and then place it flat to measure and mark out more -- e.g. mrk the center between the two points, then the center between those...
Another, sligthly better way is to print out a degree wheel, glue it onto some thick cardboard and to cut the center for the pipe out for a snug fit.
Then just mark in even spacing as provided by the degree wheel over the pipe.
You want to have about 3-4cm of distance between the markings.
For the actual pins get creative and use PVC glue and preferably a plastic that glues well with it, otherwise you need to revert to 2k based glues or resins.
The tips off cheap pens should work if cut off or anything else that is conical, not too long and with a diameter of no more than 5mm.
Transfer the same markings in terms of distance onto either side of your paper roll.
Make sure they are really parallel and that in a true straight line.
Add a strip of good sticky tape either side of the paper - preferably the good kind for office use that does not stretch when you try to rip it off the roll.
The sticky tape should by on the underside of the paper- or the invisible backside if you will.
Now get one of these hole punches for your document folder use and punch out the marking on your paper.
Hint: Remove the catch tray and place a light onder the thing - this way you can see the hole in the puncher and align the marking with ease ;)
Once you have all the holes use these stickers to re-inforce these punch holes - they come cheap on a roll from your favourite office suply store or good supermarket.
I would use a lonf and thin ruler over the paper to ensure the stickers are place exactly at the same height on either side of the paper.
Last but not east place both ends of your roll onto the roller and oer the pins so you can glue the sheet to the roll you need - doing it on the roller with the paper locked in the pins ensures a better alingment of the two ends ;)

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Downunder35m
Downunder35m

1 year ago

Get a small 3V DC motor wih a gearbox ;)
Use a 5mm rod for the rollersand slide some latex tubing over it.

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Jack A Lopez
Jack A Lopez

1 year ago

You know, in the olden days there used to be various toys resembling a television, but for which the screen was actually a flexible scroll-like thing, mounted on rollers, like you describe.

An image search for, "mechanical scrolling toy television" can get us started.

https://duckduckgo.com/?q=mechanical+scrolling+toy...

One of these results, led, by way of a Pinterest collection,

https://www.pinterest.com/pin/131730357825008058/

to an actual instructable, here at Instructables-dot-com,

https://www.instructables.com/id/Low-Tech-Cardboar...

by user rchandsa.

There might be others. I am guessing most of these designs, like the ones seen in that Pinterest link above, are designed to be turned by hand, rather than electric motors.

However, really slow moving motors, or more correctly: motors with reducing gearbox, are out there.

Just a few months ago, someone, user aliasjanedoe asked this forum,
"Where can I buy really slow 5v[olt DC] motors?"

https://www.instructables.com/community/Where-can-...

How slow were the motors she sought? Circa 15 RPM, which is 1/4 rev per second, or 4 seconds to make one complete revolution. Did she find them? Who knows? She did not write back, except to say she ordered some, from somewhere.

I believe it was the Beastie Boys who uttered the words, "Low and slow. That is the tempo." Although they were probably singing about something besides DC gearmotors...
;-)

Edit: Correction. The title of that track, and the lyric also, was, "Slow and Low." Copyright 1986. Def Jam Recordings. I got it slightly backwards and misquoted it as, "Low and slow"

Where am I going with this? Well, my point is that slow moving, low powered, DC gearmotors, exist. They are out there.

Also I boldly predict that motors of this kind can successfully drive wonky, frictionful, homemade mechanisms, even junk like rollers made out of wood or paper, and bearings made of similar materials, with a rubber band used for a drive belt.

How can I be so confident this will work? Two reasons. One is that low speed gearmotors tend to have lots of torque to overcome that friction, because of the natural mechanical advantage that comes with low speed gear trains. Another reason is the mechanism is moving far too slowly for badly balanced wheels to erupt into vibration, and shake everything apart.