Studded Turntable drive issues.

[Burf2000]

One of the robots I am working on is Wheeler and consists of 2 very large wheels. These are connected to via old style studded turn tables however driving these can cause gear slip.

I use twin 8 teeth cogs to drive them (one at the top and 1 at the bottom) which then go through set of 40 to 8 to a XL pf motor.

I get a lot of gear slip on the turn table, I have cogs above the 8 teeth cog to try and stop slipping, however there is not enough room to out a beam the other side.

Maybe the only way to fix this is to go to worm gears and see if they slip less or a bigger cog

Has anyone done something really clever at driving a old style turntable?

Edited January 3, 2012 by Burf2000

[Alasdair Ryan]

Is it well braced to prevent the gear slippage ? (gearing and motor)

A worm gear is a good idea if this does not work.

[Burf2000]

Is it well braced to prevent the gear slippage ? (gearing and motor)

A worm gear is a good idea if this does not work.

At the moment I have limited room on the other side and so I might extend the turntable out 1 stud so that I can get a beam to brace it.

I am worried the locking of the worm gear may cause issues

[Ramacco]

Since I only build studless, I tried to find a studless solution for this. You told me that you had 1 stud left on the other side (I mean, not the side were the XL-motor is located). I don't own an old turntable, but used SR3D to search for a simple solution. I used a 16t gear instead of a 8t gear.

Something I also had in mind was to use a 2x4 plate with 3 holes. If you brace the 2 beams with this piece, you can put the axle from the gear through this hole.

Hopefully you understand what I mean.

Edited January 3, 2012 by Ramacco

[Burf2000]

Brilliant idea, hope to try this out tonight! thanks !

[Burf2000]

Notice the small issue with this

there is no 3 x plate with a whole in it, and if there is, the whole is between studs, the only way I could see this matching up is by using jumpers to off set everything.

I have gone with worms gears at the moment but they such big behind! they don't turn as nicely and still jump, I am going to see what else I can come up with as the turn table is under a LOT of force.

It's a interesting and difficult problem to be honest. I don't think I would have the same issue if I did it studless.

[timslegos]

I would defiantly try the worm gear if you find that the gears keep slipping, although it might be even harder to brace the worm gear.

tim

[Burf2000]

I would defiantly try the worm gear if you find that the gears keep slipping, although it might be even harder to brace the worm gear.

tim

I have tried the worm gear, I basically used 2 3 x 5 studless right angle beams to brace hold the word gear within the turn table however it still jumps a little.

There must be a way to stop it jumping?

[Alasdair Ryan]

I have came up with a idea. It seams to easy to be true,here you go.

Edited January 4, 2012 by Alasdair Ryan

[basbase]

Here is a studfull solution that may work for you:

[Burf2000]

I have came up with a idea. It seams to easy to be true,here you go.

I am pretty sure that will jump, I had it where a plate was the other side and it still jumped

Here is a studfull solution that may work for you:

That looks like a good idea, might try that tonight.

What I did work out last night is that each work gear is jumping in only 1 direction and so if I put double worm gears on (one underneath) then that should stop any jumping. I also thought I might put an axel through the wheels and drive it from the other side to.

Then came up with a plan of releasing wait off the wheels and so then would be easier to turn. I did not sleep much last night!

[Alasdair Ryan]

No my idea should not jump, i have already built it in the real already.(the axles goes though the pinholes on the turntable)

Edited January 4, 2012 by Alasdair Ryan

[Burf2000]

No my idea should not jump, i have already built it in the real already.(the axles goes though the pinholes on the turntable)

I give it a go tonight mate then, thanks for helping on this!

[Zerobricks]

Or try internal gearing with 5x 8 tooth gears?

[Burf2000]

Or try internal gearing with 5x 8 tooth gears?

Got any pictures of what your suggesting?

[Alasdair Ryan]

Superman.........

Edited January 4, 2012 by Alasdair Ryan

[Burf2000]

Superman.........

That is not 5 times 8 tooth gear? or is that a new name for a 24 tooth gear?

[Alasdair Ryan]

I was thinking that there was something not quite right ,at least you have another idea.

Could i get a link to my blog on your web site as you are my second biggest fan?The first one being Timr how i don't thing as a web site.

Edited January 4, 2012 by Alasdair Ryan

[basbase]

Got any pictures of what your suggesting?

Zblj has posted instructions for this idea in this thread:

http://www.eurobricks.com/forum/index.php?showtopic=44255

Superman.........

That's a simple but effective way to connect to the turntable . Downside is that the connection does not offer any gear reduction by itself.

[Alasdair Ryan]

Gear it down or up afterwards.

[Erik Leppen]

Gear it down or up afterwards.

Please note that no reduction also means all the torque of the whole thing must go through that one axle. You might run the risk of damaging that axle.

Better is to have a large reduction at the final step, because the faster the rotation of the driving axles, the less force is on them. A worm at the final step means a 1:56 reduction in one go, which is I think the best idea.

And if one worm doesn't work, why not try two or even four?

Let's see if I can come up with something...

Edit: I accepted the challenge and tried to create a system with four worm gears. I hope you weren't looking for a compact solution, because this is quite a large block, but I'd be surprised if this fails. :)

Drive the two downward axles in opposing directions (or flip one of the tan gears) and it should work. Although I didn't test with a motor, it feels sturdy when testing by hand. I used the 11 x 5 liftarms because these are easy to fix securely so they won't slip. The bottom half of the structure is only meant to fix those beams securely. On the other sides a 11 x 5 beam didn't fit because of the black beam running through, so I used 2 x 4 L-beams instead.

All deeplinks:

http://www.brickshelf.com/gallery/ErikLeppen/Techniques/TurntableDriveIdea/turntabledrive2012_11.png

http://www.brickshelf.com/gallery/ErikLeppen/Techniques/TurntableDriveIdea/turntabledrive2012_12.png

http://www.brickshelf.com/gallery/ErikLeppen/Techniques/TurntableDriveIdea/turntabledrive2012_13.png

http://www.brickshelf.com/gallery/ErikLeppen/Techniques/TurntableDriveIdea/turntabledrive2012_14.png

http://www.brickshelf.com/gallery/ErikLeppen/Techniques/TurntableDriveIdea/turntabledrive2012_15.png

http://www.brickshelf.com/gallery/ErikLeppen/Techniques/TurntableDriveIdea/turntabledrive2012_16.png

http://www.brickshelf.com/gallery/ErikLeppen/Techniques/TurntableDriveIdea/turntabledrive2012_17.png

http://www.brickshelf.com/gallery/ErikLeppen/Techniques/TurntableDriveIdea/turntabledrive2012_18.png

http://www.brickshelf.com/gallery/ErikLeppen/Techniques/TurntableDriveIdea/turntabledrive2012_19.png

A few renders have some parts removed to show the inside structure. I used a lot of colors to make it easier to distinguish parts. Notice that I created a studded sturcture to suport the turntable using the stud connections. This strengthens the connection.

Edited January 4, 2012 by Erik Leppen

[timslegos]

The first one being Timr how i don't thing as a web site.

I have been thinking about it and actually in one class at school we are making websites for asssignment, but i just dont have the time at the moment .

Edit: I accepted the challenge and tried to create a system with four worm gears. I hope you weren't looking for a compact solution, because this is quite a large block, but I'd be surprised if this fails. :)

Drive the two downward axles in opposing directions (or flip one of the tan gears) and it should work. Although I didn't test with a motor, it feels sturdy when testing by hand. I used the 11 x 5 liftarms because these are easy to fix securely so they won't slip. The bottom half of the structure is only meant to fix those beams securely. On the other sides a 11 x 5 beam didn't fit because of the black beam running through, so I used 2 x 4 L-beams instead.

I dont think that will ever fail! Now if you hook up an xl motor to each input, it would be unstopable .

tim

[Saberwing40k]

here's something you might try, courtesy of erikleppen

this is just a sampler, go to his brickshelf folder for more. link

sorry about the redundancey, did not see this at the bottom.

Edited January 4, 2012 by Saberwing40k

[Smrgol]

I dread to see the motor that would make those gears skip

[basbase]

Here is a 1:24 drive that seemed to be pretty solid when I tested it. It uses Alasdair Ryan's suggestion to put a 24 tooth gear in the center of the turntable. To strengthen the axle, 3 gears are joined together with 4 long pins. Full instructions available here.