General > General Technical Chat
Force multiplier
electrodacus:
--- Quote from: PlainName on February 09, 2023, 06:45:36 pm ---
--- Quote ---It is not just a kinematic animation it takes into account the forces involved so that it reflects how it works in real life.
--- End quote ---
But someone elses animation that did the same was discounted in favour of your belief. You cannot have it both ways. No, you should not have it both ways - clearly, you are doing your best to achieve the former.
--- End quote ---
You can make an animation based on kinematics only (not representing what happens in reality) or you can make an animation including the effects of forces.
electrodacus:
--- Quote from: cbutlera on February 09, 2023, 07:54:37 pm ---
A pantograph is a very similar mechanism to your articulated table shown above (4 struts and 4 hinge joints), and it too is only anchored at two points. And yet it works, it is not locked. Why does your version of Newton's third law make the articulated table behave as a rigid object, but not the pantograph?
--- End quote ---
Please build this out of cardboard and test as likely you can not visualize what will happen. That Pantograph is very different in the way the connections are made and also the place where force is applied.
And I already shown that it can not move in this video https://odysee.com/@dacustemp:8/stick-slip-removed-from-front-wheels:0
Or are you accusing me of faking that video ? Or do you have an alternative explanation for that ?
First 15 seconds shows that mechanism is locked F2=F1
The last few seconds shows that allowing slip at input wheel results in movement against the direction of applied force using energy storage.
cbutlera:
--- Quote from: electrodacus on February 09, 2023, 08:43:20 pm ---
--- Quote from: cbutlera on February 09, 2023, 07:54:37 pm ---
A pantograph is a very similar mechanism to your articulated table shown above (4 struts and 4 hinge joints), and it too is only anchored at two points. And yet it works, it is not locked. Why does your version of Newton's third law make the articulated table behave as a rigid object, but not the pantograph?
--- End quote ---
Please build this out of cardboard and test as likely you can not visualize what will happen. That Pantograph is very different in the way the connections are made and also the place where force is applied.
And I already shown that it can not move in this video https://odysee.com/@dacustemp:8/stick-slip-removed-from-front-wheels:0
Or are you accusing me of faking that video ? Or do you have an alternative explanation for that ?
First 15 seconds shows that mechanism is locked F2=F1
The last few seconds shows that allowing slip at input wheel results in movement against the direction of applied force using energy storage.
--- End quote ---
I don't need to build a pantograph out of cardboard. I have a real one, I have used it, and it works just as shown on the Wikipedia page.
In a recent message you wrote this
--- Quote ---...
I see what your view was but this simple problem wrongly understood has huge implications in all fields of engineering and science.
I'm not a physicist and I'm not enjoying explaining this (not am I good at explaining) but I do not see anyone else offering to explain this and it looks like majority memorize "facts" instead of properly understanding.
...
--- End quote ---
You seem to have taken on the mission of teaching the world how to understand Newton's third law. Well teach me! Please answer my question. Why does your version of Newton's third law make the articulated table behave as a rigid object, but not the pantograph?
Nominal Animal:
--- Quote from: electrodacus on February 09, 2023, 08:34:17 pm ---
--- Quote from: Nominal Animal on February 09, 2023, 06:44:45 pm ---How about you tell us exactly what kind of example vehicle and its behaviour would convince you.
--- End quote ---
Yes this similar belt or even chain driven vehicle will convince me.
--- End quote ---
I'm actually utterly surprised you say that! Okay, I'll start working on it. I need to buy at least one cheap set for the chain, and some work lights so I can take an acceptable video of it working using my Ye Olde Phone (Honor 8 from late 2016/early 2017), so give me a day or two to get it done.
Is the LeoCAD model of it useful for reproduction purposes, or is the video and images of the vehicle sufficient?
Is it okay if I replace the driving wheels with sprockets on a rack, to maximize traction and avoid slipping? Or are rubbery wheels on whatever surface it is put on more convincing for you?
--- Quote from: electrodacus on February 09, 2023, 08:34:17 pm ---But are you assuming that I faked the videos?
--- End quote ---
No, it's just that a vehicle that fails to show something is not proof that it is impossible. I am telling you your vehicle was poorly constructed, and really cannot prove anything one way or another. (And, remember that one example that fails, does not show that it is impossible; it only proves that that one example fails.)
Lego Technic are precision components. Even though they are toys, their manufacturing tolerances are extremely tight, on the order of 2 micrometers (0.002 millimeters, less than one ten thousandth of an inch): higher than most metal machine shops' capabilities. They are also quite rigid, capable of withstanding quite high bending forces. This is what makes them excellent for engineering and mechanism examples.
Lego downside is their light weight, which means that wheels typically lack traction and tend to slip. It can be worked around by adding weight (coins, anything metal, fishing lure weights). As the set I used for the trike had large plastic rubber tires, they were perfect for adding weight and increasing traction (larger contact area).
IanB:
--- Quote from: Nominal Animal on February 09, 2023, 09:03:31 pm ---I'm actually utterly surprised you say that! Okay, I'll start working on it.
--- End quote ---
Before you go to too much effort, please be aware that this video exists:
https://imgur.com/a/lTqAFg6
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