Hi,

I am looking to create a project that pushes an arm against another object with a constant force. I originally thought I could just use a DC motor and have the gear held steady against something and vary the force by varying the current to the motor. However, I think the motor might overheat if I do it this way. Is this correct and if so, does anyone have any ideas of how this can be accomplished?

Thanks for your help!

Just realized I probably should have put this in the robotics forum.

Well how much force?

You might use an air compressor and piston. The piston could be as simple as a syringe.

I just got the vacuum air pump from all electronics to play around with. I figure with some sort of receiver I should be able to get a lot of work done on both the pressure and vacuum side.

Ralph

Hi Ralph,

Thanks for replying!

The maximum force I need is about 70 Newtons on the pressures side and no pull force needed. Would that jive with the vacuum air pump? I couldn't tell from the product description on that website. What do you mean by 'receiver'? Is that the part that physically connects to the part you are trying to move?

I am not sure if my application is different since I don't really need the device to move, I more need it to apply a force against the object (there might be some movement to a small amount of elasticity of the materials). I am assuming the solution is the same for both applications though?

Cheers!

I believe the little commpressor I referencesd will put out 40psi!

Have to look up Newtons to psi :-)

A receiver is a tank to hold your air or vacuum. It helps maintain a steady pressure especially with a small volume pump like this.

If all you need is to just apply a "force against the object" could you use a weight?

You could mount the weight on a servo to move it on and off the object.

Darn I could'nt wait for Newton to psi conversions, so 70 Newtons is 15.736625971010001 lbs.

So this would be doable with a air pump you could apply the force by hand even.

Ralph

Thanks for this. I will look into getting a pump!

Hey Ralph,

What kind of power supply are you planning for that air pump?

That is a 12v dc pump, oh I see the price has gone up.

The label is in German so I can not see if there is any load rating.

I have 12v 15 amp power supply off ebay that I might start with.

Ralph

Would using two 9V batteries work as well?

You would have to use a regulator to get to 12 volts but yes you can use any source.

The biggest concern might be amperage, how fast the/a battery gets consumed.

What is the object that you want to apply pressure to?

Ralph