2 position clutch ring with two independant clutch gears

[SNIPE]

Hi,

Is there a way to have a two position clutch but where it selects either gear A or B while the disengaged gear is stationary.

Putting a clutch ring between a 16 tooth ot 20 gear and a 16 tooth idler gear or 20 tooth idler gear has two positions but this selects BOTH gears if the clutch is enaged in the idler gear.

I know how to do it using a 3 position switch but the middle switch position causes synchronisation problems to cut a long story short, and this counter rotates the opposite gear, instead off letting it be stationary.

Regards, Snipe

 

Edited March 23, 2021 by SNIPE

[DrJB]

I think the real issue/challenge is NOT the clutch ... but the gear itself. If gears are meshing, they'll all be spinning together no matter what. And, you cannot stop any gear with just a clutch. You need to replicate what they do in older machine-tools where a gear can slide on an axle (red 8-teeth) and acts as an idler to engage/disengage gears.

In modern manual transmissions, gears are always engaged and gear selection is always accomplished by synchronisers/clutches ... In older transmissions however, it was a set of gears that slides on an axle, an enabled different gears to mesh. In fact older transmissions (still used on machine tools) are very fuel efficient because only the needed gears  were engaged, not all of them.

[TeamThrifty]

Use a differential to give it a choice, and use worm gears to make it impossible for torque to flow back to the stationary gear.... if you can visualise what i'm saying?

[Void_S]

To have a disengaged gear staying stationary, you should rotate the axle with a clutch ring, However it crosses your idea.

2 hours ago, TeamThrifty said:

Use a differential to give it a choice, and use worm gears to make it impossible for torque to flow back to the stationary gear.... if you can visualise what i'm saying?

I like this solution. I had an idea to use it in the 6x4 / 6x2 truck with two modes:

• "6x4 heavy-hauler 1:1" mode when rear tandem is fully driven via the open inter-tandem (between rear axles) differential
• "6x2 easy-ride 2:1" mode when one axle is lifted and locked via the clutch gear. So the remaining axle rotates only and has 2:1 ratio (two times faster than the drivetrain).

So, in the general case, there is a differential and the clutch ring at the fixed (constantly stopped) axle, which locks A or B differential outputs. Or leaves them both opened.

 

[doug72]

I have a similar problem with a change over gear for a train GBC module I am building. It needs to snap over quickly.

I use a rubber band to assist this and at same time hold red lever in position.

I hope to use a system of trip levers to make the change over.

Edited March 23, 2021 by Doug72

[SNIPE]

Ok so if I use clockwise for 0 and counterclockwise for 1 then it needs to perform the following logic:

If I have a motor that only rotates in one direction which rotates the clutch ring

If the clutch selects gear A and rotates A clockwise and B anticlockwise
And if the clutch selects gear B it rotates gear A anticlockwise and B clockwise

so my original idea works then  :D the output idlers are just tied to a single 28 tooth gear which is the true output.then I copy this again twice to get the folllowing posssible outputs:

000 - ADD
001 - SUB
010 - MOV
011 - JMP
100 - LDA (load A register)
101 - LDB (load B register)
110 - undecided, maybe STA ((store A) but mov can do this anyhow  IIRC)
111 - undecided maybe STB ((store B) but mov can do this anyhow IIRC)

The friction pin on each 28 tooth gear prevents vibrations from moving it and the 20 tooth gevel gears when the clutch is in the middle position sos this is perfect (unless the middle position causes problems which I fear but we will see)

Edited March 23, 2021 by SNIPE

[SNIPE]

done! I ran out of gray 28T gears so I used a 28T idler gear.

the battery box switch is blocked off so can only go one direction

 

Edited March 23, 2021 by SNIPE

[DrJB]

Not sure I understand your solution. In you very first post you wrote that you wanted some gears to NOT rotate ... Yet, in your solution, all gears are always meshing, and always rotate ???

[SNIPE]

31 minutes ago, DrJB said:

Not sure I understand your solution. In you very first post you wrote that you wanted some gears to NOT rotate ... Yet, in your solution, all gears are always meshing, and always rotate ???

yeah I decided to change it

[gyenesvi]

This seems quite an interesting project based on the bits of information and the video, however, from the available info I don't quite understand how you plan it to work. You are building a simple mechanical calculator, right? Can you elaborate on the encoding you mention? If I understand correctly, you want to use rotation directions of a set of gears to encode a set of bits, right? And this will be the part that represents the selected instruction in your CPU?

[SNIPE]

Thats all correct yeah. 3 bits with two possible values = possible 8 instructions 3 registers (A, B, X).

However some instructions will actually use more than one "opcode". The opcodes are the individual logic mechanisms.

Some instructions if theyre simpler may only need one mechanism i.e a single opcode.

I want to have CMP too but im still deciding on the remaining two instructions.

Of course none of this is trivial so im taking a day or 2 off to get my head out of a pickle.

Edited March 24, 2021 by SNIPE

[gyenesvi]

Quite a nice idea to explain and visualize how a computer computes :) It reminds of Charles Babbage's Analytical Engine, always wondered how that works.

So will the registers be using the same encoding, the direction of rotation? I am guessing that you will be able to set the value of (each bit in) each register with switches, right? How many bits per register are you planning? And then it will be able to calculate the given operation on the given data, and 'show' the results somehow? I guess you need a way to translate back the direction of rotation into a switch position in the end..

Wondering why you start with the instruction set, have you managed to implement arithmetic already, like an adder or something?

[SNIPE]

1 hour ago, gyenesvi said:

Quite a nice idea to explain and visualize how a computer computes :) It reminds of Charles Babbage's Analytical Engine, always wondered how that works.

So will the registers be using the same encoding, the direction of rotation? I am guessing that you will be able to set the value of (each bit in) each register with switches, right? How many bits per register are you planning? And then it will be able to calculate the given operation on the given data, and 'show' the results somehow? I guess you need a way to translate back the direction of rotation into a switch position in the end..

Wondering why you start with the instruction set, have you managed to implement arithmetic already, like an adder or something?

I have worked on logic stuff with lego in the past, I started with the instruction set first because I kinda had a random good idea on how to encode the instruction set.

I did see a working lego LCD display before so it would be cool to interface with that but to keep it simple for now im just looking at which direction the output gears are spinning and slow the motor down to see that better. Same encoding yeah.

I think ill have 3 bits per register but this is undecided.

Yes there will be clutches with levers for the A and B registerand X is for the result, no DRAM yet.

Edited March 24, 2021 by SNIPE

[gyenesvi]

Well, will be interesting to see how this evolves, after a quick search, I found that arithmetic has indeed been implemented before, although that was based on presence/absence of rotation, and not rotation direction, wonder how the two systems will compare. Will you be posting progress updates?

[SNIPE]

4 hours ago, gyenesvi said:

Well, will be interesting to see how this evolves, after a quick search, I found that arithmetic has indeed been implemented before, although that was based on presence/absence of rotation, and not rotation direction, wonder how the two systems will compare. Will you be posting progress updates?

Certainly, I will post updates. I did try to make my design in the original post more compact but then it uses more gears but less specialized gears.

There may be a way to do the same as above using 3 four wide differentials and 3 clutchrings arranged in a pyramid.

As for the logic "blocks" in lego, I know you can do addition and subtraction using a differential, you can also do drive but not reverse drive (kinda like a worm gear but this is linear+parralel not purpenducular)

You can also make a bus using the same differential which allows input A and B to drive the output but the inputs do not drive each other, so one can be stationary or in reverse of even going a different speed to the other input.

Then of course theyre multiplexers and demultiplexers which is just merging several moving axeles into one axle using gears, and vice versa for demux

There is also rotational gate thingys used in the gearbox of set 9396 (see here) and you can add additional outputs at different rotational positions not just one like in the video.

So all of the above "logic blocks" combined in different ways should be enough to get the logic for each instruction done and get the registers done.

I have thought about using logic based on the speeds of gears too but thats more an option if doing it this way gets too-too hard.

Edited March 25, 2021 by SNIPE

[gyenesvi]

Interesting to see that those mechanisms that you list can be useful for implementing logic, looking forward to it, thanks!