How do I double wrap bull wheel on rope tow?
How do I double wrap bull wheel on rope tow?
(OP)
I've made a pretty sweet rope tow that is in need of some help.
I'd like to eliminate some of the rope tension in my design.
Presently, much tension is needed to provide enough traction to drag skiers up the hill
A double wrapped bullwheel would save the day.
I'll assume that my 26" bike wheel will have to go and a wider, smoother wheel of the same diameter will be needed to let the wrapped rope get out of its own way.
I've tried double wrapping the bike wheel but the rope only ties itself in knots as it can get out of it's own way.
any suggestions?
here's a quick vid of my machine in action on our little hill.
It finished up the winter on our 800 foot hill with 120' vert
http://www.youtube.com/watch?v=K32OyNa5ByA
Thanks
FK
I'd like to eliminate some of the rope tension in my design.
Presently, much tension is needed to provide enough traction to drag skiers up the hill
A double wrapped bullwheel would save the day.
I'll assume that my 26" bike wheel will have to go and a wider, smoother wheel of the same diameter will be needed to let the wrapped rope get out of its own way.
I've tried double wrapping the bike wheel but the rope only ties itself in knots as it can get out of it's own way.
any suggestions?
here's a quick vid of my machine in action on our little hill.
It finished up the winter on our 800 foot hill with 120' vert
http://www.youtube.com/watch?v=K32OyNa5ByA
Thanks
FK





RE: How do I double wrap bull wheel on rope tow?
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RE: How do I double wrap bull wheel on rope tow?
Mike Halloran
Pembroke Pines, FL, USA
RE: How do I double wrap bull wheel on rope tow?
If you need 2 or more wraps, you will need to pull the rope off the wheel, pass it through an angled guide/idler, and back onto the wheel
To make a continuous rope go "two wraps" around a pulley, without doing the above, implies that the rope must slide along the pulley axis. Which is counter to the idea of having enough friction between rope and pulley to reduce rope tension...
RE: How do I double wrap bull wheel on rope tow?
I'm going to mock up a twin wheel setup. Much like btrueblood describes.
Like a 10 speed bicycle, it'll have 2 pulleys .
The pull rope will make a trip around the main bull wheel, then, make a trip around a smaller second pulley at a angle. Then the rope will make another trip around around the bull wheel and then return.
The setup will look a bit like the setup in WillieDog's video response but will be rigged differently as to get 2 wraps on the bull wheel
I'll fab it up in the coming weeks and keep you posted.
Thanks for helping me get my brain in gear
FK
RE: How do I double wrap bull wheel on rope tow?
The pulley on the arm assist the fairlead that allows the rope to lay on the bull wheel properly.
There are several variations of the pot haulers out there.
http://www.go2marine.com/product.do?no=99481F
You could make the system with one pulley or single purchase if you move the fairlead pulley to about 2/3 out from the center of bull wheel. This will allow you to pull all type of things through the bull wheel.
Try not to go over wraps on the bull wheel if you can.
RE: How do I double wrap bull wheel on rope tow?
The last line should read two wraps on the bull wheel.
RE: How do I double wrap bull wheel on rope tow?
I have since designed, built, installed and tested my rope tow.
It now pulls like a freight train with zero slippage.
Check out the pics of the final design here
http://w
RE: How do I double wrap bull wheel on rope tow?
I like the amount of purchase you achieved on the drive sheave.
RE: How do I double wrap bull wheel on rope tow?
We love a happy ending.
... guards removed for clarity, of course.
Mike Halloran
Pembroke Pines, FL, USA
RE: How do I double wrap bull wheel on rope tow?
Mike does have a point. Have seen people get "stuck" to rope tows, whether due to panic-grip syndrome, or actual ice freezing their gloves to the rope I don't know which. Typically there is a "gate" about 10-20' downhill from the bull wheel or return pulley, rigged to a kill switch or E-stop for the motor.
I've never seen guards per se on the pulleys, though. Typically a fence or snow berm is enough to keep people well away from the business ends of the tows.
So, how much is an all-day lift ticket? :)
RE: How do I double wrap bull wheel on rope tow?
Skiing is free for all, conditions permitting.
Thanks.