Parking brake for a shaft/motor/ball screw

[GeorgeEllwood]

Hello,
I'm working on something that will use a ball screw. I'd hoped to use a lead screw so it couldn't be back driven but this is proving very difficult. So I'm going back to plan A a ball screw but trying to find a brake to stop it being back driven. This would be be to fit on a shaft about 28mm diameter and to restrain a torque of ~15Nm. The brake doesn't need to slow the shaft down, just to stop if from rotating. The shaft probably won't stop in exactly the same rotation position each time. Ideally this would be magnetically controlled so that if power was lost the brake would release.
Could someone point me in the direction of a brake like this?
Thanks
George

 

[tbuelna]

If your drive uses an electric motor, you can purchase servomotors that have an integral friction brake. The friction brake is engaged when the motor stops driving, and it disengages when the motor starts driving.

 

[Jboggs]

There are lots of different kinds of brakes. They vary in design, function, durability, operation, etc. Sounds like you want a spring-engaged brake (failsafe on). You can operate it manually, or with air, or electric signal. Check ThomasRegister.com or any good local power transmission distributor (like Motion Industries or Grainger). Also, most ballscrew suppliers could recommend some options for you.