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Force multiplier

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electrodacus:

--- Quote from: IanB on February 07, 2023, 02:20:34 am ---You cannot apply F1 because there are no forces. If the belt is turning as in the picture then the wheels will be turning clockwise and the assembly will be moving to the right. No forces are required for this to be happening.

There is no need to discuss case (b) as that is different and therefore not relevant.

--- End quote ---

I'm glad you say that case (b) is different since while it is not true it means you likely understand case (b).
Belt will not need to move in order to apply a force F1 to the mechanism in case (a).

All 3 case represent the same thing floating body/cylinder/GND and thus they can not do force or voltage amplification.
In case (c) output current can not be different from input current but you can still have a current different from zero same as you can have a force different from zero in both case (a) and case (b)

Maybe you can explain case (b).  Can you apply a force F1 in that case and can F2 be anything other than equal an opposite to F1 ?
And if so what is the problem there ? Why can you not have F2 say 2 * F1 ?

IanB:

--- Quote from: electrodacus on February 07, 2023, 02:35:05 am ---Belt will not need to move in order to apply a force F1 to the mechanism in case (a).
--- End quote ---

You cannot apply a force at F1 in case (a), because the wheel will turn, and by yielding reduce the force to zero.


--- Quote ---All 3 case represent the same thing floating body/cylinder/GND and thus they can not do force or voltage amplification.
--- End quote ---

The first case is not floating as it has a wheel resting on the solid red block, and the other wheel is resting on the belt, therefore not floating either.

electrodacus:

--- Quote from: IanB on February 07, 2023, 02:49:15 am ---You cannot apply a force at F1 in case (a), because the wheel will turn, and by yielding reduce the force to zero.

--- End quote ---

The wheel will not turn unless the belt is elastic and the stretching of the belt allows the wheel to rotate while force will increase.
You are imagining that the axle friction is so high and that is the reason why the belt stretched so much in my experiment but that is not the reason (not even close).
The F1 wants to push the vehicle to the left while the left wheel wants to push the vehicle to the right with the force F2 equal and opposite to F1.
It is the same as case (b)
I think you are imagining that F1 only wants to turn the wheel and not push the vehicle in that same direction and that will be true if the belt was not connected and the wheel axle had no friction.
But due to the way the belt is connected it is basically a locked gearbox no different from having the wheels welded to the body.



--- Quote from: IanB on February 07, 2023, 02:49:15 am ---The first case is not floating as it has a wheel resting on the solid red block, and the other wheel is resting on the belt, therefore not floating either.

--- End quote ---

The wheels can rotate independently of the body but not independent of each other due to belt.
The body drawn in blue is not connected to anything.  If I were to connect the body to ground right in between the red box and the treadmill then F2 can be 2xF1 (assuming 2:1 gear ratio) and so that back wheel can push the red box with a force twice as large relative to grout as the input F1 also relative to ground.
Same thing for case (b) where the cylinder body will need to be connected to ground.

You can not do force multiplication with just two points of contact and you need a minimum of 3 points in order to do that no matter the device.
Just have a search on google images for "torque multiplier wrench" and you will see that all of them require 3 points of contact in order to work.

IanB:

--- Quote from: electrodacus on February 07, 2023, 03:17:46 am ---
--- Quote from: IanB on February 07, 2023, 02:49:15 am ---You cannot apply a force at F1 in case (a), because the wheel will turn, and by yielding reduce the force to zero.


--- End quote ---
The wheel will not turn unless the belt is elastic and the stretching of the belt allows the wheel to rotate while force will increase.

--- End quote ---
The belt is not elastic and there is no stretching. This is an ideal diagram. There are no physical effects such as stretching, friction or inertia. Everything is perfect and ideal.


--- Quote ---You are imagining that the axle friction is so high and that is the reason why the belt stretched so much in my experiment but that is not the reason (not even close).

--- End quote ---
No friction. No stretching. Perfectly ideal.


--- Quote ---The F1 wants to push the vehicle to the left while the left wheel wants to push the vehicle to the right with the force F2 equal and opposite to F1.
It is the same as case (b)

--- End quote ---
There is no F1 because there is no force. No force because no friction, no inertia, nothing to resist any attempted force applied. No resistance, no force.


--- Quote ---I think you are imagining that F1 only wants to turn the wheel and not push the vehicle in that same direction and that will be true if the belt was not connected and the wheel axle had no friction.
But due to the way the belt is connected it is basically a locked gearbox no different from having the wheels welded to the body.

--- End quote ---
No locked gearbox as clearly seen from the diagram and mathematical analysis.
You can build it and see. If you want to avoid stick-slip energy storage, use cogs and toothed gears so that no slipping is possible. The assembly will simply move to the right with no force required if the belt moves as indicated.


--- Quote ---
--- Quote from: IanB on February 07, 2023, 02:49:15 am ---The first case is not floating as it has a wheel resting on the solid red block, and the other wheel is resting on the belt, therefore not floating either.
--- End quote ---

The wheels can rotate independently of the body but not independent of each other due to belt.

--- End quote ---
Precisely.


--- Quote ---The body drawn in blue is not connected to anything.  If I were to connect the body to ground right in between the red box and the treadmill then F2 can be 2xF1 (assuming 2:1 gear ratio) and so that back wheel can push the red box with a force twice as large relative to grout as the input F1 also relative to ground.
Same thing for case (b) where the cylinder body will need to be connected to ground.

--- End quote ---
There are no forces, therefore no force multiplication.


--- Quote ---You can not do force multiplication with just two points of contact and you need a minimum of 3 points in order to do that no matter the device.
Just have a search on google images for "torque multiplier wrench" and you will see that all of them require 3 points of contact in order to work.

--- End quote ---
There are no forces, therefore no force multiplication.

electrodacus:

--- Quote from: IanB on February 07, 2023, 04:11:04 am ---No locked gearbox as clearly seen from the diagram and mathematical analysis.
You can build it and see. If you want to avoid stick-slip energy storage, use cogs and toothed gears so that no slipping is possible. The assembly will simply move to the right with no force required if the belt moves as indicated.

--- End quote ---

There is a difference between math and physics.

I build it and saw this gearbox is locked. You can see for yourself in this video  https://odysee.com/@dacustemp:8/stick-slip-removed-from-front-wheels:0
Force is applied by the paper to the right wheels (input wheels). As you can see there is no rotation and the entire vehicle is dragged in the direction that the force is applied.
The applied force is equal with the frictional force at the back wheels and it is significant (much larger than what it will be required if the gearbox was not locked).  This is exactly the same design as the on in diagram (a). 

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