Winch problem

[Gregor]

Originally Posted by richwong

What do you have "pulling" the brake cable?

Sorry, didn't see this until now.

See the attached image.

[Chinske4296]

Dry an anti back drive system, via ratchets or some other means. Last year we used a ball shifter, instead of a second stage we took the gears out acting as a neutral gear. I see no reason you couldn't use a similar function with a ratchet.

[Chinske4296]

We had a ratchet on the shaft allowing the ratchet to turn with out moving the shafts connected to the motor, thus preventing backdrive.

[rookierunner]

Although the software fix described above will work and cims are very durable... there is another non-software option. As worm gear will not allow the motor to back drive. I wouldn't recommend a window motor for the task, but they are an example of a gearbox with a worm gear.
Good luck to you this season.

[GortGortGort]

One solution not mentioned is the use of a two drum winch design with one cable from one drum pulls up while the other cable pulls down .

A spring or latex tubing attached to your lift with continuous upward force properly adjusted to your lifting weight will work fine to control motor/ gearbox back-drive. It really makes your winch work to pull the lifting arm down first
and less force to pull weight up.

http://info.vulcanspring.com/first-robotics-competition

Check out voucher from Vulcan Spring . You could add this quickly to your bots
lift to stop the back-drive with out changing your design as long as your winch
is not relying on a gravity return lift arm . Are you using a single cable drum ? Photo of your winch might be useful for us to help you solve the problem.

http://www.chiefdelphi.com/media/photos/41279?