Pulleys - modern sorcery and witchcraft.

General » General Discussion

Site Notices

[ARCHIVED THREAD] - Pulleys - modern sorcery and witchcraft. (Page 1 of 4)

Posted: 12/7/2019 11:26:41 PM EDT

I never knew how pulleys worked until I saw this video. Pretty cool.

Why Snatch Blocks are AWESOME (How Pulleys Work) - Smarter Every Day 228

https://www.youtube.com/watch?v=M2w3NZzPwOM

Posted: 12/7/2019 11:29:11 PM EDT

[#1]

Neat stuff. I've always been fascinated by them.

Posted: 12/7/2019 11:29:19 PM EDT

[#2]

F=MA, and you can't push with a string.

All you need to know.

Posted: 12/7/2019 11:30:29 PM EDT

[#3]

As someone that grew up on sailboats I am confused why people get confused.

Posted: 12/7/2019 11:30:49 PM EDT

[#4]

The simple machines unit was easily the best unit of all of elementary school.

Posted: 12/7/2019 11:32:06 PM EDT

[#5]

To oversimplify things, they're basically the rope version of hydraulics/pneumatics.

Posted: 12/7/2019 11:34:33 PM EDT

[#6]

Modern!?

I know for a fact that they date back hundreds of years.

I'll never forget seeing Burt Lancaster beat the stuffing out of a dozen pirates with one.

Posted: 12/7/2019 11:34:49 PM EDT

[#7]

Quote History

Quoted:
The simple machines unit was easily the best unit of all of elementary school.

View Quote

Yup - inclined plane, lever, wedge, wheel and axle, pulley, screw, and C4

Oh, and a neat lego channel

Testing Lego gear and pulley systems - part 2

https://www.youtube.com/watch?v=bWgTRHH656Y

Posted: 12/7/2019 11:36:24 PM EDT

[#8]

Quote History

Quoted:
Yup - inclined plane, lever, wedge, wheel and axle, pulley, screw, and C4

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
The simple machines unit was easily the best unit of all of elementary school.

Yup - inclined plane, lever, wedge, wheel and axle, pulley, screw, and C4

I tried to explain to a customer's kid one time how a screw was just a ramp twisted around an axle.....his mother said "they haven't done simple machines yet".

I told him it would be the highlight of the year for a kid like him.

Posted: 12/7/2019 11:38:41 PM EDT

[#9]

Spent a lot of time working with them when I designed cranes. On cranes we called them sheaves.

Posted: 12/7/2019 11:41:16 PM EDT

[#10]

Pulleys aren't all that modern.

Posted: 12/7/2019 11:42:46 PM EDT

[#11]

Good find. Subscribed.

Posted: 12/7/2019 11:47:02 PM EDT

[#12]

I keep a couple of snatch blocks in my recovery kit for my truck winch.

Posted: 12/7/2019 11:48:01 PM EDT

[#13]

Smarter every day is a good channel. He has a cool video about silencers.

Posted: 12/7/2019 11:49:55 PM EDT

[#14]

Neat

Posted: 12/7/2019 11:51:21 PM EDT

[#15]

Greek crane with pulleys, bc.

Posted: 12/7/2019 11:52:52 PM EDT

[#16]

Math works.

Posted: 12/7/2019 11:53:25 PM EDT

[#17]

I enjoyed that one OP.

Posted: 12/8/2019 12:27:20 AM EDT

[#18]

Guy was confusing. Could have just said that the same amount of work is being done, but you are trading (less) force for (greater) distance. The tension BS is irrelevant.

Posted: 12/8/2019 12:31:55 AM EDT

[#19]

Nice post. I had 5 acres of bull pine, and lodge pole logged on my property so I've got an awful lot of stumps to pull.

I bought this to refresh my memory on pully's, there's not much to it that isn't in this manual.

Posted: 12/8/2019 12:34:15 AM EDT

[#20]

I have some old block and tackle out in the shop, I need to get it set up. Would be useful at times.

Posted: 12/8/2019 1:06:21 AM EDT

[#21]

Quote History

Quoted:
Good find. Subscribed.

View Quote

He has the best channel on YouTube if you're an engineering nerd. He has quite a few gun related ones and even discusses that he is a gun owner.

I absolutely love his channel. The one about where they store moon rocks was fascinating!

Posted: 12/8/2019 1:14:12 AM EDT

[#22]

Quoted:
I never knew how pulleys worked until I saw this video. Pretty cool.

https://www.youtube.com/watch?v=M2w3NZzPwOM

View Quote

Seriously? How else are they supposed to work?

I use a kit to lift my Jon boat out of the way to the ceiling of my carport.

Posted: 12/8/2019 1:20:46 AM EDT

[#23]

Quote History

Quoted:
Spent a lot of time working with them when I designed cranes. On cranes we called them sheaves.

View Quote

A sheave is a component of a pulley, AKA pulley wheel. Pulley is an assembly.

Posted: 12/8/2019 1:32:19 AM EDT

[#24]

Pulleys and their great great grand children, modern cranes are absolutely amazing.

I only own a small 28tn crane. But even it is impressive.

Being able to lift 3000lbs 57 feet away is awesome.

Posted: 12/8/2019 1:37:22 AM EDT

[#25]

A good rope and pulley is worth its weight in gold to move cut trees around.

Also helped today to get my new pole saw unstuck

Posted: 12/8/2019 1:40:52 AM EDT

[#26]

So to be clear, his experiment with the stuck jeep provided no mechanical advantage, correct? Simply using the snatchblock alone and moving the pull point from the tree to the bumper did not magnify force in any fashion.

Posted: 12/8/2019 1:43:03 AM EDT

[#27]

Quote History

Quoted:
So to be clear, his experiment with the stuck jeep provided no mechanical advantage, correct? Simply using the snatchblock alone and moving the pull point from the tree to the bumper did not magnify force in any fashion.

View Quote

It doubled the force. That's what they do.

Posted: 12/8/2019 1:46:26 AM EDT

[#28]

Quote History

Quoted:
It doubled the force. That's what they do.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
So to be clear, his experiment with the stuck jeep provided no mechanical advantage, correct? Simply using the snatchblock alone and moving the pull point from the tree to the bumper did not magnify force in any fashion.

It doubled the force. That's what they do.

Doubled the force at no sacrifice to distance pulled?

I would understand a second pulley, or block and tackle setup where the force is redirected twice. But only being run through one pulley should only change the direction of force, not the magnitude... ?

Posted: 12/8/2019 1:47:35 AM EDT

[#29]

Quote History

Quoted:

Doubled the force at no sacrifice to distance pulled?

I would understand a second pulley, or block and tackle setup where the force is redirected twice. But only being run through one pulley should only change the direction of force, not the magnitude... ?

View Quote

No, the expense is half the distance traveled.

You trade one for the other.

It isn't just a redirection, because it was anchored back to the jeep.

Posted: 12/8/2019 1:50:53 AM EDT

[#30]

Quote History

Quoted:

Doubled the force at no sacrifice to distance pulled?

I would understand a second pulley, or block and tackle setup where the force is redirected twice. But only being run through one pulley should only change the direction of force, not the magnitude... ?

View Quote

Nope. If winch is pulling on the line and the other end of the line is pulling on the bumper, the bumper is being pulled by twice what the winch can haul. The Jeep moves at half the reel speed.

If you're doing an off axis pull, where the winch line terminates at an anchor (tree or whatnot), then, yeah, you're simply changing the direction of travel between the Jeep and the anchor.

Posted: 12/8/2019 1:53:06 AM EDT

[#31]

Quote History

Quoted:

Nope. If winch is pulling on the line and the other end of the line is pulling on the bumper, the bumper is being pulled by twice what the winch can haul. The Jeep moves at half the reel speed

View Quote

Yep, the object moving ends up moving at half the speed of the line, but with double the force.

Posted: 12/8/2019 2:02:07 AM EDT

[#32]

Quote History

Quoted:
Nope. If winch is pulling on the line and the other end of the line is pulling on the bumper, the bumper is being pulled by twice what the winch can haul. The Jeep moves at half the reel speed

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:

Doubled the force at no sacrifice to distance pulled?

I would understand a second pulley, or block and tackle setup where the force is redirected twice. But only being run through one pulley should only change the direction of force, not the magnitude... ?

Nope. If winch is pulling on the line and the other end of the line is pulling on the bumper, the bumper is being pulled by twice what the winch can haul. The Jeep moves at half the reel speed

As a guy who (I thought) had used pulleys effectively as a wrecker operator, I'm feeling pretty stupid about this, but I'm going to keep talking through it until it makes sense.

You're proposing that if the winch were to reel in 12" of cable, the jeep would only move toward the pulley 6"? I still can't fathom that- there's nowhere for that distance to get lost.

So is the part of this that I'm missing in the fact that the pull point and the anchor point are the same?

Posted: 12/8/2019 2:06:57 AM EDT

[#33]

Quote History

Quoted:

As a guy who (I thought) had used pulleys effectively as a wrecker operator, I'm feeling pretty stupid about this, but I'm going to keep talking through it until it makes sense.

You're proposing that if the winch were to reel in 12" of cable, the jeep would only move toward the pulley 6"? I still can't fathom that- there's nowhere for that distance to get lost.

So is the part of this that I'm missing in the fact that the pull point and the anchor point are the same?

View Quote

Yes. The cable is doubled on itself so the distance that the object travels is halved. The drum is still moving at the same speed as always but the cable has to cover twice the distance to move the object as it normally would in a straight pull.

The key to it is that the end of the cable is connected back to the jeep. That doubles the force. If you connect it to anything else, you redirect the force but do not double it.

Physics wont give you something for nothing, but it will trade with you.

Posted: 12/8/2019 2:23:32 AM EDT

[#34]

Quote History

Quoted:

I keep a couple of snatch blocks in my recovery kit for my truck winch.

View Quote

Same.

Always interesting to see new to me rigging scenarios with them being used to redirect pulling force in different directions.

Posted: 12/8/2019 2:24:15 AM EDT

[#35]

I look at pulleys similar to a gear reduction system. You're trading displacement (movement) for power.

Posted: 12/8/2019 2:24:22 AM EDT

[#36]

Quote History

Quoted:
Yes. The cable is doubled on itself so the distance that the object travels is halved. The drum is still moving at the same speed as always but the cable has to cover twice the distance to move the object as it normally would in a straight pull.

The key to it is that the end of the cable is connected back to the jeep. That doubles the force. If you connect it to anything else, you redirect the force but do not double it.

Physics wont give you something for nothing, but it will trade with you.

View Quote

Think of it this way. You are basically doing a gear reduction. You know how on a 10 speed bicycle when you come to a hill, if you down shift, and you continue to peddle at the same speed, you go up the hill slower but it's a lot easier to peddle?

That's exactly what the pull does.

Posted: 12/8/2019 2:24:45 AM EDT

[#37]

Quote History

Quoted:
I look at pulleys similar to a gear reduction system. You're trading displacement (movement) for power.

View Quote

Dammit

Posted: 12/8/2019 5:59:15 AM EDT

[#38]

I remember rigging a block and tackle out of scrap and loose pulleys to haul some heavy boxes up into the attic. my nearly grown kids thought it was magic.

Posted: 12/8/2019 7:21:16 AM EDT

[#39]

Had he consulted modern sailboat racers he would've had his mind blown.

Attached File

Posted: 12/8/2019 7:27:50 AM EDT

[#40]

Great video.

Loved the old guy who turned up and just knew how to do things.

Dying breed around here

Posted: 12/8/2019 7:37:53 AM EDT

[#41]

Always loved Destin's channel and I know he is an actual rocket scientist, but the way he stood and filmed near the anchor point of the winch of the Jeep made me cringe. Ever see an anchor or winch cable fail under load? Someone posted a liveleak video of that happening here a while back. Snatch block came back through the windshield and made the poor driver's face look like the Predator.

Posted: 12/8/2019 7:40:36 AM EDT

[#42]

Quote History

Quoted:
Nice post. I had 5 acres of bull pine, and lodge pole logged on my property so I've got an awful lot of stumps to pull.

I bought this to refresh my memory on pully's, there's not much to it that isn't in this manual.

https://www.AR15.Com/media/mediaFiles/103648/IMG_0197_JPG-1187477.jpg

View Quote

I've never seen that book. Looks handy. Off to Amazon.

Posted: 12/8/2019 7:48:36 AM EDT

[#43]

Quote History

Quoted:
I look at pulleys similar to a gear reduction system. You're trading displacement (movement) for power.

View Quote

I'm no engineer, but I believe you are right. The winch gearing/motor may be only experiencing it's current load, but the cable, snatch block, anchor spot and bumper are experiencing double that load.

Posted: 12/8/2019 7:54:34 AM EDT

[#44]

They're a good purchase.

Posted: 12/8/2019 8:00:14 AM EDT

[#45]

Quote History

Quoted:
Had he consulted modern sailboat racers he would've had his mind blown.
https://www.AR15.Com/media/mediaFiles/234934/20191208_062035_jpg-1187684.JPG https://www.AR15.Com/media/mediaFiles/234934/20191208_062035_jpg-1187685.JPG https://www.AR15.Com/media/mediaFiles/234934/Screenshot_20191208-062757_Chrome_jpg-1187693.JPG

View Quote

I watch a lot of sailing videos on Youtube. Not that i actually have any real interest to sell everything, buy a tall boat and hit the high seas. The mechanics of it all just simply fascinates me. We moderns discount what an amazing accomplishment transoceanic technology really was. The Europeans with their scientific approach and the "feelz" methods of the Polynesians before them simply amaze me. Both groups had brains and balls like coconuts.

Posted: 12/8/2019 8:00:29 AM EDT

[#46]

Quote History

Quoted:
Always loved Destin's channel and I know he is an actual rocket scientist, but the way he stood and filmed near the anchor point of the winch of the Jeep made me cringe. Ever see an anchor or winch cable fail under load? Someone posted a liveleak video of that happening here a while back. Snatch block came back through the windshield and made the poor driver's face look like the Predator.

View Quote

I won't disagree with you, but I'm thinking the Jeep wasn't stuck so minimal force was required. It was simply a demonstration.

Posted: 12/8/2019 8:16:32 AM EDT

[#47]

Tag for later

Posted: 12/8/2019 8:31:39 AM EDT

[#48]

Love pulleys?
Here you go!!

Attached File

Posted: 12/8/2019 8:53:01 AM EDT

[#49]

Quote History

Quoted:
Love pulleys?
Here you go!!

https://www.AR15.Com/media/mediaFiles/71410/plot_combine-649966_JPG-1187718.JPG https://www.AR15.Com/media/mediaFiles/71410/plot_combine-649966_JPG-1187719.JPG

View Quote

Rube Goldberg making farm equipment now?

Posted: 12/8/2019 8:56:10 AM EDT

[#50]

Quote History

Quoted:
I've never seen that book. Looks handy. Off to Amazon.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
Nice post. I had 5 acres of bull pine, and lodge pole logged on my property so I've got an awful lot of stumps to pull.

I bought this to refresh my memory on pully's, there's not much to it that isn't in this manual.

https://www.AR15.Com/media/mediaFiles/103648/IMG_0197_JPG-1187477.jpg

I've never seen that book. Looks handy. Off to Amazon.

No need,here it is

https://manuals.directutor.com/HPE/Rigging-Handbook.fm5-125/index.html?page=1

[ARCHIVED THREAD] - Pulleys - modern sorcery and witchcraft. (Page 1 of 4)

General » General Discussion

Warning

Confirm Action

About AR15.COM

Stay Connected

Newsletter

Contact Us