Has anyone thought about how to winch themselves up to the bar. I was thinking about taking apart a boat trailoring winch and using cable. Any ideas?
Yep. Looks like this is a popular idea. I know we have been considering it. Here is a thread with a discussion about how winches work and some opinions of them.
http://www.chiefdelphi.com/forums/showthread.php?t=23648&highlight=winch
ive desinged a winch
[size=3]its a Plug&Play winch that reals 15" Per second with a max lift load of 486 Lbs
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I don’t want to thrash, insult, or even knock the idea of a winch (trust me we would be using one…), but given the 10ft/s rule, how do you plan to address the case of missing the bar with your winch (I’m assuming you’re throwing it or somethng of that nature)?
the winch looks nice tytus… seems like you are suggesting to use chiphua motor which is also known as atwood. there are lot of teams out there who would use the chiphua for drive train… a lot of team out there had drill and chiphua using for drive train last year, and they might do it again. what would you suggest using some other motor such as window or globe… its probably gonna take a while for the winch to move… but there is going to be a lot of torque…
were talking about winches not about how your getting the cable up on the bar Save that for elsewhere
Actually I think he’s using the van door motor. Notice the gearbox at the end. This is better than using the CIM because the van door motor uses a worm gear, which means it cannot be backdriven(at least theoretically) so you don’t have to worry too much about it falling after power is cut at the end of the match.
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Nice looking winch. Thanks for posting it, we might use it.
Have you considered cutting a helical groove in the drum to keep the cables from crossing and tangling? This is common for many automotive applications (window lift mechanisms, power sunroofs, etc.)
How will you anchor the ends of the cable into the drum?
Looks like the power van door motor in your design which is a non-backdriveable worm gear, meaning it requires no brake to keep you hangin. An appropriate application. 
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its just a hole in the drum
If you have more questions about my winch Im me or e-mail me. Keep the back and fourth klutter off the forums.
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i apologize… i was about to edit the whole post when you replied back… i didnt really pay a lot of attention to the whole post from tytus… and i looked at the winch mechanism from the bottom view… and i am pretty sure that anybody will make that mistake thinking its a atwood… if they have just seen it from the bottom view… once again… i apologize…
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As an offshoot of the winch idea and as a way to save weight I would suggest researching lightweight stronger than anything rope. Particularly the type used on sailboats that is designed to hold incredible loads. Check it out:
http://www.layline.com/llf/llpages/htmlp2origa/page2.htm
Just an example:
1/8" diameter
.6 lbs/100 feet
2200 lbs break load
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I was thinking the same thing. Infact, I have been researching boat trailor winches that are designed for rope. I figure I would strip them down.
Use some other mechanism, such as a arm to put the hook up
a great big old helium balloon!
You would think so, but unfortunately I believe that’s not the case with this particular worm drive gear; I seem to remember using it for a lift one time, only to find out it would backdrive when the power was cut - it had an oddball pitch angle so that it could be backdriven (a safety feature since it’s used for closing van doors). I know they’ve changed the particular van door motor we get in the kit since a few years back - can anybody confirm if this motor can be backdriven?
I can tell you that the van door motor will back drive. Plus you need to gear this motor better than you have it.
Here is a picture of us hanging
http://www.valleytech.k12.ma.us/robotics/images/2000Pictures/roboti87.jpg
That motor was being gear for a 24t to 48t. So if you think that buy just putting a drum on it would work let me save you some time.
The tyco motors into a gear box would be the best bet for this. 15,000 rpm reduced 200:1 would give you a good starting motor and if you put two of them together you would have a fast strong winch. you could say you could climb up at a rate of 6 pi = around 18" per second. which is 1 1/2 foot per second within 6 seconds you will be at 9 feet.
Make sure your winch can pull you and one other robot. by using the pass competitions someone might be holding you down
The van door motors Can be backdriven it is just verv difficult
how difficult? will it support the 130 lbs when the power is cut? That’s really all I need to know…
The van door motor can be backdriven rather easily. I was able to do it with my bare hands, I doubt it will be able to hold up a 130lb robot. Another thing to look into is an electronic brake. I’m not completely familiar with the electronics, but I’m pretty sure the speed controllers have a jumper on them that will enable a “brake” of sorts. It electronically prevents the motor from being back-driven. I can’t say if it will be able to hold 130lbs, but the two combined (van door motor + electronic brake) might be able to do the job.
[edit] The electronic brake remains enabled as long as the robot has power, so it will work after the robot is disabled at the end of the match.
a pneumatic arm w/ winch attached to that could be an idea…