any success with winches?

[Jay TenBrink]

we are using a 6" cylinder with a bar to stop back drive. this is a one ticket up until we reset it.[/quote]

We will use winch motors that can backdrive (Fischer Price) and will need a device to prevent backdriving as well. Has anybody come up with an elegantly simple way to accomplish this? We would like it to be a passive device, similar to the clutch in a manual window regulator mechanism.

We'd rather not have to use a cylinder/blocker device because of the weight. Has anybody had experience using an electrically actuated servo to move a latch pawl or something like that?

[Mike Norton]

Originally Posted by Jay TenBrink

we are using a 6" cylinder with a bar to stop back drive. this is a one ticket up until we reset it.

We will use winch motors that can backdrive (Fischer Price) and will need a device to prevent backdriving as well. Has anybody come up with an elegantly simple way to accomplish this? We would like it to be a passive device, similar to the clutch in a manual window regulator mechanism.

We'd rather not have to use a cylinder/blocker device because of the weight. Has anybody had experience using an electrically actuated servo to move a latch pawl or something like that?[/quote]


http://www.valleytech.k12.ma.us/robo...02%20Claw2.jpg

If you take a look at this device it is very simple to stop a motor to back drive. we use this claw to hold onto the 180lb goals and pull them around. Vey strong.

[Bacchus]

My recommendation would be to use a ratchet and pawl. These parts are easily available from many gear companies including Berg(http://www.wmberg.com/catalog/catres... oup=RATCHETS), or if you're on a really tight budget you can probably get creative with a band saw and a grinder. I would be very hesitant to rely on a mere servo to disengage the pawl. However, something like a pneumatic with a very short throw would be suitable.

[Jay TenBrink]

Originally Posted by Bacchus

My recommendation would be to use a ratchet and pawl. These parts are easily available from many gear companies including Berg(http://www.wmberg.com/catalog/catres... oup=RATCHETS), or if you're on a really tight budget you can probably get creative with a band saw and a grinder. I would be very hesitant to rely on a mere servo to disengage the pawl. However, something like a pneumatic with a very short throw would be suitable.

I would agree that it would not be practical to disengage a pawl that was under load using just the force available in the servo. A servo could work if you take the load off of the pawl first.

Since our winch will also be used to extend and retract the ball handling device, a one time/one way ratcheting winch would be a problem. If the winch is used for lifting the robot only, a spring loaded ratchet would be fine.

[Rickertsen2]

Originally Posted by Jay TenBrink

we are using a 6" cylinder with a bar to stop back drive. this is a one ticket up until we reset it.

We will use winch motors that can backdrive (Fischer Price) and will need a device to prevent backdriving as well. Has anybody come up with an elegantly simple way to accomplish this? We would like it to be a passive device, similar to the clutch in a manual window regulator mechanism.

We'd rather not have to use a cylinder/blocker device because of the weight. Has anybody had experience using an electrically actuated servo to move a latch pawl or something like that?[/quote]
whats wrong with a spring loaded pawl? Just look at the hand power winches they well at home depot. As mentioned above you could easily fabricate something like his with tools as simple as a a bandsaw.