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High IMA Pulley Task

Posted: September 5th, 2017, 9:16 am
by Unome
See rule 4.b.vii for details.

The IMA must be at least 7, so that will require a significant number of pulleys. Pushing a switch with the rising weight seems like the simplest way to trigger the next action, as long as you can control the ascent path of the weight (a tube?).

Re: High IMA Pulley Task

Posted: September 6th, 2017, 7:39 pm
by Tesel
It'll require some pulleys, yes, but as long as you just do 4 wheels on top fixed in place and 3 wheels on bottom fixed together, it's a pretty manageable system. That is if I remember my simple machines right which is a big if.

Re: High IMA Pulley Task

Posted: September 7th, 2017, 7:49 am
by RJohnson
Tesel wrote:It'll require some pulleys, yes, but as long as you just do 4 wheels on top fixed in place and 3 wheels on bottom fixed together, it's a pretty manageable system. That is if I remember my simple machines right which is a big if.
That's not quite how I remember it. I believe it is the number of movable pulleys * 2. IE, you would have four on top and bottom, the four on the bottom moving to get an IMA of 8. To get to exactly 7, I guess one would remove the last pulley on the top and be pulling up rather than down.

Re: High IMA Pulley Task

Posted: September 7th, 2017, 9:09 am
by Unome
This is what you want, with the pulleys separated out. Just use this number of pulleys, and arrange them similar to this diagram.
IMA 7 pulley.png
IMA 7 pulley.png (6.6 KiB) Viewed 9184 times

Re: High IMA Pulley Task

Posted: September 7th, 2017, 9:58 am
by ScottMaurer19
https://docs.google.com/drawings/d/1AjO ... sp=sharing

Here is a link to a google drawing I made of what (90% sure) a 7 IMA pulley system can look like.

Re: High IMA Pulley Task

Posted: September 7th, 2017, 10:29 am
by Unome
ScottMaurer19 wrote:https://docs.google.com/drawings/d/1AjO ... sp=sharing

Here is a link to a google drawing I made of what (90% sure) a 7 IMA pulley system can look like.
I can probably chip in the other 10%, that looks right to me.

Re: High IMA Pulley Task

Posted: September 7th, 2017, 10:56 am
by RJohnson
Gotcha, not quite what I had envisioned but functionally equivalent.

Re: High IMA Pulley Task

Posted: September 7th, 2017, 12:26 pm
by Tesel
RJohnson wrote:
Tesel wrote:It'll require some pulleys, yes, but as long as you just do 4 wheels on top fixed in place and 3 wheels on bottom fixed together, it's a pretty manageable system. That is if I remember my simple machines right which is a big if.
That's not quite how I remember it. I believe it is the number of movable pulleys * 2. IE, you would have four on top and bottom, the four on the bottom moving to get an IMA of 8. To get to exactly 7, I guess one would remove the last pulley on the top and be pulling up rather than down.
I should have explained that better... it's all about the number of ropes supporting the load. Unome did a great drawing - since there's 7 ropes supporting the load, there's an IMA of 7, which is what I was getting at.

Re: High IMA Pulley Task

Posted: September 12th, 2017, 9:05 am
by raxu
There is a pulley system I remember from Compound Machines that use few pulleys to get an arbitrarily high IMA: Differential Pulley. I did a description in the scioly wiki Compound Machine page.

There are a few drawbacks though: it is harder to build, requiring the wheel and axle-like structure. Additionally, the supervisor may not familiar with the setup and does not see how it can have IMA>=7. The benefit is the low number of pulleys used!

Re: High IMA Pulley Task

Posted: September 12th, 2017, 10:06 am
by Unome
raxu wrote:There is a pulley system I remember from Compound Machines that use few pulleys to get an arbitrarily high IMA: Differential Pulley. I did a description in the scioly wiki Compound Machine page.

There are a few drawbacks though: it is harder to build, requiring the wheel and axle-like structure. Additionally, the supervisor may not familiar with the setup and does not see how it can have IMA>=7. The benefit is the low number of pulleys used!
It's an interesting idea. However, it would also be a little harder to implement due to the difficulty of pulling on it, whereas with a regular pulley you just drop an object 70 cm to pull the weight up 10 cm.

Edit: Nevermind, that's not possible. The dropped object would definitely have to roll down a ramp or something, since the device's maximum height is 60 cm.