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11
General stuff / Re: Picking things back up
« Last post by webby2 on March 10, 2024, 01:20:37 am »
another note; a belt and pulley or a chain and sprocket are one-way force transfer devices.  You can not transfer any force on the slack side of the belt\chain.  You can MAKE and external constraint system to allow you to transfer a push for either but by themselves they can only transfer a pull.
12
General stuff / Re: Picking things back up
« Last post by webby2 on March 09, 2024, 01:41:55 pm »
just as a note; I am using gravity as a source, BUT, I have to supply both the motive force and the force of opposition, both of these are courtesy of gravity.
13
General stuff / Re: Picking things back up
« Last post by webby2 on March 09, 2024, 01:37:40 pm »
making parts and playing with things,, fun stuff.

So I have made this one setup that actually has a few rough spots but for the most part moves OK, a little resistance but it rotates.
I found 2 electric motors that weigh 80g and am using those for my drop weights.

In the setup I am playing with right now I have 4 pulleys that go round and round but do not rotate :) Roberval anyone.

I have my 2 drop weights on opposite pulleys so the system should be balanced but it is not, both weights move the same distance, one down the other up and it is always the same weight, within this range of rotation, that will fall with extra force raising the other weight.

I actually was expecting either nothing, or the opposite of what I have so this is getting interesting.
14
General stuff / Re: Picking things back up
« Last post by webby2 on March 02, 2024, 08:28:12 am »
I have rebuilt my test-part, I have made it smaller and with only 4 subsystems.

They all are mounted in bearings on a frame and they are all connected to each other with a single common part.  They are all connected so that there rotational change is the same and in the same direction as each other.

I have test pulleys that are 31mm radius and are mounted on each subsystem shaft.  I am using these to test input and output stuff so that I can identify and follow what the feedback systems are within the whole system.

On one pulley I have wrapped a string with a 180g mass hanging on it, well I can not find my other 180g mass right now so on another pulley that is opposite the first one I have wrapped a string with a 250g mass hanging on it.

The drop and lift distances are the same due to the pulley radius being the same and the angle change being the same.

There are force changes within the systems and in one point of view that can be viewed as a 3:1 and this is where the feedback part is that I am looking into, it should cancel that advantage.

So,, I start the first test with the 180g mass low and the 250g mass high, let the system slip through my fingers and the 250g goes down and the 180g goes up nicely for a 180 degree rotation.  Now I reset my system for the other 180 degrees of rotation but I set the 180g mass high and the 250g mass low.

I use Mr. Finger to help the 180g mass to move down, a small amount of rotation and the 250g mass will drop back down, go past that value and the 250g mass no longer can lift the 180g mass, Mr. Finger is noticing a "heavy sluggish" feel but it is the same for either direction of rotation, keep rotating and Mr. Finger notices this "feeling" is reducing until there is a point where it is very easy to rotate the system in either direction a little bit, 10-20 degrees.

I tried to add 70g to the 180g mass to see if it would lift the 250g mass, well it did not work so well and the sluggish feeling got much worse.

I have to improve a few parts and then make sure that I have not created an artificial force potential with the setup, nothing like loading a spring without realizing it to mess with things.
15
General stuff / Re: Picking things back up
« Last post by webby2 on February 14, 2024, 08:34:01 am »
not really useful for much but an interesting method.
16
General stuff / Re: Picking things back up
« Last post by webby2 on February 12, 2024, 07:28:22 am »
I have drawn up something that is a little confusing.

I have a fixed input distance of 120mm
I have an angle of change at a constant 3.65 degrees for the input.  I think this means my input work is going to be the same amount for any of the transfer system lengths.


the output is 45 degrees of rotation on a 10mm arm.
the longer I make the transfer system components the interactive angle between the input and output changes, ie: at one set of length values (468mm) the range goes from 106.01 to 74.83, many times longer (12m) the range goes from 115.8 to 71.37.  This is in consideration that a 90 degree interaction angle would be the best force transfer.

I think that this could be a kind of non-rotating lever (NRL) in that my input distance is always the same.

17
General stuff / Re: Picking things back up
« Last post by webby2 on January 20, 2024, 04:52:38 am »
sidetrack:
I have my multi-systems interacting with the input, so named because that is the way I have been viewing it to distinguish direction of throughput not as the ONLY way of using it.

My input and the multi are connected as such that one rotation of one drives one rotation of the other, they are a 1:1 rotation.
In looking for alternative methods of adding a constraint to stop the massive deflection of shafts and stuff I can up with a way but it has an interesting issue.  The direction of rotation of the multi can go either CW or CCW but the input always rotates in the same direction CCW.

In one view then they are a 1:1 but in the other they are a 2:1, that is I can rotate the multi in the opposite direction of the input and one rotation is still one rotation which means that between them there are 2 revolutions.
This is not all new stuff, at least to me and I am guessing that it will end up leading to nowhere, but it is kind of fun.
18
General stuff / Re: Picking things back up
« Last post by webby2 on January 11, 2024, 02:44:00 am »
so my chain and sprockets are adding more losses than I thought.  If I only use them to transfer between 2 sprockets I have an increase from about 0.5N up to about 3.5N.  To take up all the slack and just start the motion of transfer is close to the drop weight value but to get the system to move more than that takes initially a lot more and then it drops down while motion is maintained,, somewhat due to Mr. Hand not being really good for this.

I took all that off and used one of my alignment jigs instead of the chain and things were interesting.  I increased the drop weight to 4.5N and, depending on where in the rotation I measure, the input force goes from about 3.2N up to over 6N.

Watching the test-part bend and twist with all this is a bit of an eye opener as to how much constraint is going to be required.
19
General stuff / Re: Picking things back up
« Last post by webby2 on January 07, 2024, 06:06:35 am »
simple solutions are good.

I am however having significant issues with the plastic parts deforming and not providing for a smooth interaction, when I use force the parts are almost grating by each other instead of sliding and rolling smoothly.  I have one small spot where the input force to start things moving is less than 2.4N but then things get sticky and it takes over 4N to move but then the system kind of shoots forward and stops again until I pull further on the input.

It would seem that I need to use hard surfaces instead of plastic ones.
20
General stuff / Re: Picking things back up
« Last post by webby2 on January 06, 2024, 03:11:58 am »
I have made some parts strong enough so that I can actually see what the parts look like as they are interacting, those are the input arm and the interactive drive unit.  This allows me to see what the lever system is doing as the forces are being applied and transferred from one area to another.

I have a pivot shaft that is supposed to be rigid but even with a small amount of force being transferred those rigid pivots are bending.

I am aware of these forces but I did not appreciate the reality of how large they become so I need to constrain that reactionary force issue before I can proceed.
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