Best motor/servo/thing to "pull stuff"?

Hi guys,

I'm asking from the people who know better. That means you guys :slight_smile: I'm so new to this thing I don't yet even know what words to use to start googling.

So, I need to pull an object. Weight between 2 to 8 kg. With AA batteries (currently I have 4 x 1.2V batteries, but i'm not limited to this. Any batteries works.)

I need to pull the object maximum 15 cm.

Speed is not an issue. It can take for example 2 seconds the pull the object.

I'm currently using a servo mg955.

But I don't really need a servo, because the object that I pull has physical limits where it can more. So I could pull it just "one way as long as the motor can" until it stalls.

So I think some short of a motor could work here too. Or motor like a drill, which push/pulls objects.

So: which kind of motor/servo/thing would be the best to pull an object which weights 2 to 10kg and can work with batteries?

When you say "pull" I presume you mean pull across a smooth level surface rather than lift against gravity. It makes a big difference to the amount of "pull" required.

There is no simple answer to your question because it mainly depends on the amount of friction. You don't say whether there are wheels. You really need to measure the force required to move the load.

...R

Thanks Robin for your answer.

I'm sorry. I was not clear. I need is to pull 2kg to 10kg object. I cannot really calculate the friction, but the specs of the mg955 are fine: Stall torque: 8.5 kgf·cm (on 4.8 V power source)

Otherwise i'm happy for the servo, but in my case, the servo can only go 180 degrees. And when not powered, it's really hard to "pull back" the object which is attached to the servo. (since the servo is kind of locked when not powered).

I was wondering if there are better ways to "pull stuff" than with a normal servo like mg955.

Are there any good "small winches" or motors that could just "pull with high torque" and being powered with batteries?

All ideas are welcome.

So basically. I have a object X which i need to pull with a rope. What kind of motor would pull the rope the best?

(Speed is not an issue here.)

You can get a continuous rotation servo and it may even be possible to convert the servo you have to continuous rotation. Google should find explanations of how to do it.

You might also investigate sail-winch servos.

However that won't solve the problem of being able to pull the load away from the "winch". If the servo is unpowered the resistance to pulling the load is due to friction in the gear train. With any small motor you will need a similar gear train with the same problem.

A very much larger motor that needs less gear reduction to produce the same torque will probably be easier to "unwind" when de-powered.

But you may also find that the large motor with less gearing winds too quickly.

Is there some reason why you can't run the servo in the other direction when you want to "unwind"?

...R