How Does a Winch Work?

[Aaron Lussier]

I have searched far and wide for an answer to this question and I can not find it. Does a winch, more specifically a small electrical winch, use worm gears/spur gears/helical gears/other types of gears in order to lift the heavy loads that winches lift. Any information would be very helpful, How Stuff Works does not have any info, and that is usually where I fin dall the info I need. Thanks.

Aaron

[Adam Y.]

Im really not sure about what gears they use but they generally have some method of locking the gearing in place. Usually they use a rachet to lock the gears and to ensure that the items do not fall down.

[NoRemorse]

I believe they ratchet, with the motor usualy mounted parralel to the axis of the spool

[KyleGilbert45]

In 2000 we had a "wench" on our robot to pull the bot off the ground while hanging on the bar. I have a really good picture of it but I cant find it. When I find it i'll post it.

[Gadget470]

What you are trying to think of is a Ratcheting Winch.

A winch itself is very simple, defined as "A stationary motor-driven or hand-powered machine used for hoisting or hauling, having a drum around which is wound a rope or chain attached to the load being moved."
In our case, a Stationary motor-driven machine used for hoisting, having a drum which is wound a rope or chain attached to the load being moved.

A very useful site for information on winches (and a few other things) is:
http://pergatory.mit.edu/2.007/hando...c.html#winches

It also has an excel file for calculating data about the winch using real values from the motor.

A ratcheting winch however is very slightly different. It has something to ratchet along the gears

Note the shape of the ratcheting gear. When turning clockwise, the gear pictured will lock into the two pieces that ratchet along the gear. when turning counter-clockwise, the two pieces will "jump" to the next tooth. This is a means for safety and preventing slipping.

The effect of this can however be replicated without a ratcheting gear. There is more than one way to lock a gear box.

[Frank(Aflak)]

The van door motor has a worm gear built onto it. The thing about worm gears is that they cannot be backdriven, so it will accomplish the same thing that a ratchet would . . . except you can reverse direction with it, which you could not do with a ratchet unless you had a servo-powered release mechanism.

I don't know the specs for the van door, but I would assume that it has enough torque after the worm gear transmission to directly power a winch that can lift 130lbs . . if the spool diameter is small enough, anyway.

I'll look into that.

[Drew Hopman]

While we are on the topic of how things work… Does anyone know how telescoping arms work? I had seen last year team 890 had a telescoping arm but I can’t figure out how to get it to work. Please help me.
Drew Hopman
Team 801

[Frank(Aflak)]

Originally Posted by Drew Hopman

While we are on the topic of how things work… Does anyone know how telescoping arms work? I had seen last year team 890 had a telescoping arm but I can’t figure out how to get it to work. Please help me.
Drew Hopman
Team 801

heh, you must have the same idea we do.

Ok, telescoping arms.

They are relatively simple, and this idea on making one is just something that hit me in the face while I was thinking about it. Call it intuition, or whatever. There are probably better methodes, but here goes:

You have the man (non moving) stage of you arm, right? you make the secondary (moving) stage of your arm capable of sliding up and down the main stage. Now, at the TOP of the main stage, attach a roller chain sprocket, a small nylon one with a built in bearing would probably be best on weight considerations. Now, run a chain (you can use really small chain for this) over the sprocket and anchor it at the BOTTOM of the secondary stage. Now, with the other end of the chain you can attach a motor, so the motor can real in the chain. As it does this, the secondary shaft is forced to slide up the main shaft, and you have a powered, telescoping arm. You can make the chain complete the loop if you want more control (I.E. you attach the secondary stage to one link in a continuos loop of chain . . that loop is your main stage.

You can expand this into a three stage arm if you add a sprocket at the top and bottom of the secondary shaft . . so the chain goes over the main shaft's top sprocket, under the secondary's bottom sprocket, over the secondary's top sprocket, and is anchored to the bottom of the third stage.

Another simple design I saw last year is using your elastic tubing to load your telescoping arm, and you could pull a locking pin out allowing the elastic tubing to extend the arm. You can't retract it, though.

Pneumatics could work for a short one, but I'm currently working on an inventor design of my chain one.

[Drew Hopman]

Originally Posted by Frank(Aflak)

heh, you must have the same idea we do.

Ok, telescoping arms.

They are relatively simple, and this idea on making one is just something that hit me in the face while I was thinking about it. Call it intuition, or whatever. There are probably better methodes, but here goes:

You have the man (non moving) stage of you arm, right? you make the secondary (moving) stage of your arm capable of sliding up and down the main stage. Now, at the TOP of the main stage, attach a roller chain sprocket, a small nylon one with a built in bearing would probably be best on weight considerations. Now, run a chain (you can use really small chain for this) over the sprocket and anchor it at the BOTTOM of the secondary stage. Now, with the other end of the chain you can attach a motor, so the motor can real in the chain. As it does this, the secondary shaft is forced to slide up the main shaft, and you have a powered, telescoping arm. You can make the chain complete the loop if you want more control (I.E. you attach the secondary stage to one link in a continuos loop of chain . . that loop is your main stage.

You can expand this into a three stage arm if you add a sprocket at the top and bottom of the secondary shaft . . so the chain goes over the main shaft's top sprocket, under the secondary's bottom sprocket, over the secondary's top sprocket, and is anchored to the bottom of the third stage.

Another simple design I saw last year is using your elastic tubing to load your telescoping arm, and you could pull a locking pin out allowing the elastic tubing to extend the arm. You can't retract it, though.

Pneumatics could work for a short one, but I'm currently working on an inventor design of my chain one.

If you come up with something in inventor i would liket to see it. Thanks for the help.
Drew Hopman

[Mike Norton]

telescoping arms take a look at this.

We use a push pull system. this system is always under tension. we we 14' with this arm in 2001


http://www.valleytech.k12.ma.us/robo...1Robot2001.jpg

went down to 17"

http://www.valleytech.k12.ma.us/robo...Bridge2001.jpg

In 2000 we use a telescope system that will go in both direction with a lot of power this one went as high as 10'

http://www.valleytech.k12.ma.us/robo...s/roboti86.jpg


http://www.valleytech.k12.ma.us/robo...s/roboti87.jpg


with a system like this you only tighten one nut to put the whole system into tension. this might look big and heavy but this telescope was made with thin alum. and light rollers. this only wieghed 15 lbs just the telescope part


I will say we have something even better than this.

[Drew Hopman]

Originally Posted by Mike Norton

telescoping arms take a look at this.

We use a push pull system. this system is always under tension. we we 14' with this arm in 2001


http://www.valleytech.k12.ma.us/robo...1Robot2001.jpg

went down to 17"

http://www.valleytech.k12.ma.us/robo...Bridge2001.jpg

In 2000 we use a telescope system that will go in both direction with a lot of power this one went as high as 10'

http://www.valleytech.k12.ma.us/robo...s/roboti86.jpg


http://www.valleytech.k12.ma.us/robo...s/roboti87.jpg


with a system like this you only tighten one nut to put the whole system into tension. this might look big and heavy but this telescope was made with thin alum. and light rollers. this only wieghed 15 lbs just the telescope part


I will say we have something even better than this.

What did you use to tension this system?

[Raul]

Originally Posted by Frank(Aflak)

The van door motor has a worm gear built onto it. The thing about worm gears is that they cannot be backdriven, so it will accomplish the same thing that a ratchet would . . . except you can reverse direction with it, which you could not do with a ratchet unless you had a servo-powered release mechanism.

I don't know the specs for the van door, but I would assume that it has enough torque after the worm gear transmission to directly power a winch that can lift 130lbs . . if the spool diameter is small enough, anyway.

I'll look into that.

The van door motor can be back driven unless the bearing screw (at the end of the worm gear) is tightened quite a bit. The problems with doing this are:
1) You lose power output by tightening it
2) It wears out and you have to keep tightening it to keep it from backdriving

Plus it might still back drive if it sees excessive force.

[Frank(Aflak)]

Originally Posted by Drew Hopman

If you come up with something in inventor i would liket to see it. Thanks for the help.
Drew Hopman

I'm working on it. Maybe I'll have it finished in a day or two.

It will be pretty rudimentary, I'm relatively new to inventor.

[Aignam]

25's made a 12' telescoping arm in 2000. I attached a picture. If you have any questions, PM me.

[MBF]

Originally Posted by Mike Norton

telescoping arms take a look at this.

We use a push pull system. this system is always under tension. we we 14' with this arm in 2001

http://www.valleytech.k12.ma.us/robo...1Robot2001.jpg

went down to 17"

http://www.valleytech.k12.ma.us/robo...Bridge2001.jpg

In 2000 we use a telescope system that will go in both direction with a lot of power this one went as high as 10'

http://www.valleytech.k12.ma.us/robo...s/roboti86.jpg

http://www.valleytech.k12.ma.us/robo...s/roboti87.jpg

with a system like this you only tighten one nut to put the whole system into tension. this might look big and heavy but this telescope was made with thin alum. and light rollers. this only wieghed 15 lbs just the telescope part


I will say we have something even better than this.

Do you have any more pictures or diagrams? My team is trying something similar this year, and any information would be helpful. Some of the doubters are still not quite seeing how the arm would work, and any concrete evidence would be useful.