DC motor opening a drawer

[crf250rider14]

Hello all, this is my first post and I must say, this is a great forum!
Ok, so I have a small wooden drawer about 6 inches wide and 10 inches long. Which is under a shelf. The drawer rests on runners under it. But now I want to hook up a small 12v dc motor from radio shack. I found a way to make the motor go in both directions using a DPDT switch. Now how would I use the dc motor to make the drawer going back and forth?
Hopefully I made this clear enough to understand.
Any help will be greatly appreaciated.
Thanks.

 

[kak111]

Fix a nut to the drawer and thread bar to motor axle. Motor fixed to shelf.
If your motor is torqueless for that, use gearbox.

 

[crf250rider14]

Wow thanks for the fast response! What do you mean by a threaded bar? I would like to keep the motor stationary and have it push the drawer open. I was thinking about something that was grooved like you said. Could I buy the bar somewhere? Or would I have to go to a machine shop and have it made up?
Thanks again for your help.

 

[kak111]

Threaded bar you should find in good hardware store.
They have those bars from 4mm......30mm ( inches ???) for about 2$ / m ( 4mm)

Hope you get drawer automation work.

 

[crf250rider14]

Hmmm. I do not really understand the idea of the threaded bar. If I put a nut into the wood of the back of the box. And the other end connected to the motor. And I turn the motor on wouldn't it just go threw the nut? It would not pull or push the drawer...
Maybe i am not understanding the whole concept that your trying to explain.

 

[kak111]

Here is the principle.
You can locate motor as you like.



KAK

You can place the motor also to the right end of the threadbar ( in pict. )
ie motor is located back the shelf. ( Make only needed parts for fasten the motor
to the chassis.)

 

[crf250rider14]

I see. It makes more sense now. Hopefully I did not put you through to much trouble making the diagram. I'll let you know how it turns out.

---------- Post added at 19:40 ---------- Previous post was at 19:29 ----------

One more question, using the design you made, will the threaded bar be sticking out when the drawer is closed?

 

[alexan_e]

If the drawer moves to the left to open then the threaded bar will be inside the drawer, suppose that the above diagram is in closed position and the front side is the left side

Alex

 

[crf250rider14]

Ohhhh. That would probably work well then.
I will have to try it.

 

[thunderboympm]

if your rack is smooth enough . You may chose the thread also. I mean the wool. It will be fast compared to thread bar system

 

[crf250rider14]

One more question, the drawer is fairly small, what size motor would work well opening and closing it? I just bought a 9-18v dc motor from radio shack. You think this is good or need bigger?

 

[alexan_e]

I have no idea of the mechanic calculations needed and even if i knew them there are also too many unknown factors like how easy the drawer slides, the weight , the thread step per revolution, the motor torgue etc.
The only answer I can give is to try it and see if it works, if not you need a stronger motor.

Alex

 

[kak111]

Do a small test.
Take a nut and bolt , same size you think to use. ( start with 4...5mm )
Attach bolt to motor axle with piece of plastic or rubber tube
and check what is the force motor can give via nut.

Regards KAK

 

[crf250rider14]

Hey do you know what websites sell gearboxs for small motors?