Accurate brake control

I would think the manufacturers of heavy duty Tow Trucks would be able to help you.

Band brakes are very hard to control consistently, I would suggest disk brakes, also motor speed control is going to have to be a major consideration if stopping position is what you are after. If you are looking to do nothing more than stop the load very fast then size the brake torque to two hundred percent of the motor torque. provide more info of the nature of the intended use and I can give more detail.

As I understand your concern, it's that braking will be proportionately consistant with pressure. Over short periods of time I believe it will be, but over the long term you will require more & more pressure due to the wear and thus reduced coefficient of friction on your brake pads. My experience is basically with drilling rig drawworks, which is an oversized winch. These traditionally, and to this day have a manually applied band brake, and frequently use an Eaton disc brake for emergency and "park" The Eaton brake can be hydraullicaly, or spring applied, depending on the desired function or available controls.

I think the traditional reason for not using hydraulic application for normal braking, is that pressure can't be sufficiently controlled to obtain the desired amount of braking, and hydraulics are basically used for on off applications.

Having said all that, the automotive industry has succesfully used hydraulic braking for 100 years, and continues to do so, but the pump is manuall activated, normally by people's feet.

I remeber one situation where we ran an airpot on a drawworks band brake, and we used the an Eaton Disc as a working brake. As I recall the airpot was used in an on/off manner as the parking brake. The system was scrapped after dropping the blocks a few times.

I think in short, it's not the pressure relief you want to rely on for consistent braking, but a sophisticated control valve that will give you sensitive pressure control.

Drillers continually say that they want to be able to "feel" the brake handle.

Look into using a (U.S. style) heavy truck air brake system...can be done with disc or drum brakes, don't know about band. I would think that band brakes would be unreliable as was pointed out in a previous post.

In my experience on older tracked vehicles, the band brakes used for steering were unreliable in that application as well. Best to go with disc brake for your application.

If you run a metallic brake disk in hydraulic fluid you can get almost unlimited life from the brake and no wear or fading with heat. Look at the brakes on John Deere 4020 and later farm tractors. The brakes last 1,000s of hours of use compared to 100's of hours of use with the best dry brakes.

Since you are going to to have a hydraulics system any way make it a good one and get all the advantages it has to offer.

GC.

Thank you all for the advice, it has been very helpful.

I think I will consider add in a load measuring point and use that as a feed back to varies the brake band actuator pressure. I will also try to get hold of Wuchita/Eaton people and see what we can come out with. will keep you all update