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Design for drive system Answered

I have ran into a issue with a project that i cannot figure the best solution for. Here is what i am trying to do. Imagine a pvc pipe setup in a ladder configuration. On top of each side of the ladder system an aluminum angle rail runs up and down each side. On top of this rail system is another square pvc piece with ball bearing mounted externally allowing the pvc square to ride up and down the rail. My issue has come from automating the pvc square to move back and forth on the this rail system. I thought of using a dc motor driving it to each end where a switch would be contacted to reverse the motor in the opposite direction. The issue is getting a motor that has enough torque to move the pvc square with about 10lbs on top of it maybe less and to do this a fairly slow motion. I had thought of maybe using a cheap 540 rc car motor, but this is where my ? comes in. How do i drive the square with the motor with out getting overally complicated. Would i be able to adjust the speed of the motor with a potentiometer? If so would i be able to keep the torque or would that reduce too? Finally is there another option that would be simplier to exectue?


I have thought of possibly going with a motor like this one http://www.sparkfun.com/products/8913 and attaching a wheel like this one http://www.sparkfun.com/products/10076 directly to the motor. I would have to mount the motor on a hinge and use a spring to keep the wheel in contact with the track. The reason i want a motor this small so that i can use double a batteries to power it without having to charge up a battery pack everytime. The issue is that im not sure a motor this small will pull the slide back and forth. Like i said the the slide will probably be around 10lbs. Im working on a new pic to get a better idea of what it will look like.

Look up how the tuning knob on an old radio works to move the dial to set the station. It is some kind of pulley thing that winds the cord or cable back and forth. Use your motor as a winch to wind up the cord and reverse it. Good luck.

How fast do you want to move the load. ? You need a geared motor to do this - direct drive won't work at all.

I would like to have it somewhere around walking speed or alittle slower, not real fast.

Windshield/screen wiper motors are perfect for this sort of thing, and a chain drive.

Using a leadscrew would be very slow, unless you buy expensive screws.


Ive added the starting design for the project, but the reason i havnt really included any drawings cause the drive system can drastically change the design of the project. The rails on top of the pvc pipes is aluminum angle and i plan to use skateboard bearings riding on the angle to guide the upper plate.

Direct or belt drive to threaded bar from the motor should work, with a nut fixed to the underside of the plate. for speed regulation, PWM is probably the best option, apart from removing cells if you are running from a battery pack. Again, some form of diagram would be helpful


7 years ago

You will need to draw a picture.

One option that you don't talk about is using a geared motor or a transmission of sorts.