[TowerTalk] Brake Winches

[Richard (Rick) Karlquist]

On 6/29/2015 8:53 AM, Patrick Greenlee wrote:
> There is more than one type of winch brake.  Worm drives above a certain
> reduction ratio won't "motor" or allow the load to turn the winch. There
> are no brake parts as such but you get full control and if you turn lose
> of the handle the load will not be able to turn the winch. No brake
> parts = no brake parts to wear or overheat in use.
>

There is no free lunch with worm drives.  The worm drive IS a brake
that is "ON" ALL the time, whether going up or down or standing still.
As such, it causes at least a 2X increase in effort going up.  Going
down, the same friction applies so that you have to apply significant
effort even with help from gravity.  All this extra effort due to
friction HEATS up the worm gear.  If you replaced the worm drive with
a recirculating ball bearing drive as used in vehicle steering, it
would get rid of the friction and also get rid of the self braking.
When you lower a tower, the gravitation energy has to go someplace,
meaning it gets converted to heat.

What is really needed is a braking system like they use for electric
cars where the energy is fed back into the battery.  Probably not
cost effective vs $150 winches.

Rick N6RK