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Discussion Starter · #1 ·
Ok WARNING, this is totally over engineered, over designed and over thought!!! But it was kinda fun figuring it all out.



Any way this is my idea for vertical masking that will also close completely to cover the screen when not in use. Once set it should be 100% accurate all the time and never need any adjusting or maintenance which were top priorities when I was doing it. No springs to wear or break, no cables that can stretch causing alignment problems. It should be rock solid. I haven't worked on anything as far as automation yet, but it will all be driven by one 12 volt motor, probably just an open/close switch to start with.


So any way let me know your thoughts on this.

DOWN LOAD THIS FILE


It is a SketchUp file so you will need Google ScetchUp to read it (free program)
 

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Wow, great looking design & drawings!

I look forward to following along with your build out.


May I offer a thought ? Wonder if timing belts & gears might be quieter than using chains & sprockets ?


Way to go Mopar man !



John
 

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How long a timing belt are you needin? I have done a lot of searching for stuff like that for my own future build. There are a coupld of places that sell open ended belts


John
 

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Very impressive design.


It looks like the masking moves via nuts on the threaded rods. But won't that make both sides move in unison, i.e. both move left or right when the rod is rotated, instead of one moves left and the other moves right?
 

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Discussion Starter · #7 ·

Quote:
Originally Posted by HDGTX /forum/post/18194753


How long a timing belt are you needin? I have done a lot of searching for stuff like that for my own future build. There are a coupld of places that sell open ended belts


John

It is 60-1/2" center of shaft to center of shaft. Any info you have would be great. I am starting to put together a parts list to order
 

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Discussion Starter · #8 ·

Quote:
Originally Posted by ilsiu /forum/post/18195830


Very impressive design.


It looks like the masking moves via nuts on the threaded rods. But won't that make both sides move in unison, i.e. both move left or right when the rod is rotated, instead of one moves left and the other moves right?

One side is right hand thread and the other is a left hand thread. So even though it is all turning the same direction they will move in opposite directions.
 

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Quote:
Originally Posted by Mopar_Mudder /forum/post/18196355


It is 60-1/2" center of shaft to center of shaft. Any info you have would be great. I am starting to put together a parts list to order

Will dig out my file folder & get back to you... Glad to help.
 

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Discussion Starter · #12 ·

Quote:
Originally Posted by petew /forum/post/18197499


I'll donate a high torque DC motor with integral gear reduction unit. It's made for operating windows. It runs on 24v nominal.


PM me if interested.

Thanks for the offer. I do have laying around a 12v motor that is made for operating the landing gear on an equipment trailer. I have to test it out some more because I don't know if it is a 1600 or 2200 rpm model and it also has a 59:1 gear box on it. I think I can eliminate the gear box and use just the straight motor. I want about 1700-1800 rpms to the screws when done.


I also don't want to drive the threaded shaft directly, I want to drive the belt/chain. Reason is: if I ran just a belt from top shaft to bottom shaft and they drove the bottom shaft with the motor directly (would be easiest), then what happens if the belt/chain happens to break or jump off... You could get a big mangled mess as the motor would still drive the bottom shaft but not the top. Guess that would be a way to correct keystone though!!!
 

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Quote:
Originally Posted by Mopar_Mudder /forum/post/18197269


I just one place that I think will have what I need, they are called SDP/SI, looks like I should be able to get what I need.


I have to figure out the RPM's on my motor first though so I can figure pulley size.

SDPSI was one of the places I was going to recommend, they have a huge amount of cool stuff. The "Coni-drive"

is neat.


Here is a link to McMasters-Carr;
http://www.mcmaster.com/#catalog/116/1044/=5ykwzs


Here is another, PolyTech Design Inc; www.polybelt.com


Another: Quality Transmission Comp (AKA: Econobelt)
www.econobelt.com


Lots of choices; Inch or metric, belt composition, belt pitch (MXL, XL ect), belt width.


I've been looking, but unable to find how much of a pulley's circumfrence (sp?) adds to the belt's length requirement; 2 x your 60.5" + that length.....


Will be interesting to see how much torque you'll need to drive those two threaded rods & masks.


John P
 

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Discussion Starter · #14 ·
If you have the picth and number of grooves in the pulley you can figure the length. I am going to get my motor figured out this weekend before I put to much effort into finding correct pulley and belt. But I am going to do the belt since I have some good souces, thanks much.


Wonder if I will need to do an idle pulley to keep the belt from slaping with that long length....
 

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Discussion Starter · #16 ·
Just an update that I have the main frame all built and am working on the treaded shafts now, been too lazy to take pictures yet. After this week end I should have it all done except for the belt and gears, need to get the motor mounted first so I can figure out belt length. So far looks like everything is working as planned.
 

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Discussion Starter · #17 ·
OK I ran into a small snag. The DC motor that I had intended to use doesn't look like it is going to work out. It has a 59:1 gear box on it that I thought I could just pull off and use the motor itself. Which I can but the actuall motor has just a tiny, maybe 1/8", shaft on it. Shaft coming out of the gear box is 1/2" so I thought the motor shaft would be close to size. Well this is way to small of shaft to put the gear on to run the belt, and I can't leave the gear box on or it will be way to slow....


So any good sources out their for a 12V DC motor that turns around 1800 rpm and has a 1/2" shaft on it? As long as I have to get a different motor how about something with a built in control for stop points?


I am guessing somewhere around 300-400 inch pounds of torque is needed.
 

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Nice plan and drawings! What is the purpose of the "extra" sprocket on the lower threaded rod?

Do you really need a lot of torque to turn the threaded rods? I have a motor from a HP-plotter that is probably turning at about 1200 o/min. I connected it to a threaded rod with a nut on it, and it seems that it takes a lot of force to stop the nut from moving up/down the threaded rod. Motor current drain is less than 1A at 12V with some load.


Gunnar
 

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Discussion Starter · #19 ·
The extra sprocket is where the motor will be mounted. Don't have a motor yet so I didn't draw it or the mount in. Also I will do a belt instead of chain.


I really don't know how much power I need. A cordless drill will turn the shaft with every thing together. But I don't have the masking material on yet which will add some resistance also, how much depends on how much tenstion is needed to keep 6' of material from sagging.
 

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Great plan, beautiful drawing!


I have been looking at a similar option that goes something like this:


1) Use a SCREW DRIVE garage opener as the main motor. You only want to use a unit with a DC motor in it. http://www.geniecompany.com/GenieCompany.aspx?cid=560 These are very quite specially when there is not a lot of load on them. The power supply can be modified to be used with outboard reversing and limit switches. You dont need the internal control board and receiver board (?sell them on ebay
)


2) The aluminum track will be used along with the carriage.

3) The track comes in short lengths and extensions are available to get the desired length.

4) Get an extra carriage (or make your own) and screw it from the opposite end so that when the screw rotates both the carriages meet in the middle.


The front ends of the maskings can be connected to the carriages in such a way that the front ends remain perfectly straight and vertical so that there is no need for a bottom screw drive!


I have always been a proponent of using weights to maintain tension on the masking. This will work great.


A BELT DRIVE unit can also work, but I like the Screw drive better.


I am a little busy these days but will try to make a diagram of the masking to carriage connection.


Teecue
 
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