How to connect two worm gears so it works like a gear rack?

[SNIPE]

Hi,

I want to make a crane boom using worm gears but when I connect two side by side so they mesh the spacing is either too short or too wide.

How can I fix this

Iv'e tried moving it half a stud along and putting a 1x1 technic brick on top of another but no luck ;/

[Alasdair Ryan]

Can you share a picture of your crane boom or your ideal setup?

Edited May 22, 2013 by Alasdair Ryan

[SNIPE]

Hi,

it either moves the just axle by sliding it out of the worm gear(left) or moves just the worm gear and not the axle (right)

then the large axle is connected to the crabber or whatever this is just for the mechanism that extends it for now most cranes use a gear strip and a gear attached.

when one worm gear rotates it moves the other one up just like a linear actuator or a nut and bolt.

Edited May 22, 2013 by SNIPE

[Alasdair Ryan]

Who's next?

[SNIPE]

Hi

thanks for the solution works niceley

I assume the bottom hole is half a stud (0.5L) across from the two top ones

[Alasdair Ryan]

Yeb,I used a long pin with pin hole in the middle (you should be able to see it).

[Zerobricks]

Why not use a combination of a worm gear and a rack?

[SNIPE]

Because they are quite short so i'm using two worm gears with some 32L axle so it will have plenty of travel

EDIT:

After finalizing the idea, the reason is, that one axle does not slide but does rotate but the other worm gear rotates and does not slide so one axle extends outwards from the other 'fixed' one this only requires two worm gears per two axles so this boom should be able to extend extremely far, now the trick is to find a strong chassis/outer shell that also is thin so when the arm is fully closed it isn't too wide.

I'm not sure if some force will move the axle or if I need something mechanical to

Only the yellow axle slides since there is only s bush at the end to stop it falling out

Edited May 23, 2013 by SNIPE

[SNIPE]

Hi

How can I get the yellow axle to slide by just using two worms gears like above, if 3 or4 are needed then that's ok but I don't want to use much more than that, the red axle is stationary but does rotate.

I think i have an idea on how to do this but its stuck way in the back of my head.

Edited May 23, 2013 by SNIPE

[Lipko]

I don't understand what you want to achieve and if the proposed or your solutions work or not.

What do you want? To slide the yellow axle by rotating the red one?

Have you tried your/others' solution with real bricks?

Does it work or not?

Is the yellow worm gear supposed to substitute the gear rack?

What's the problem with gear racks? I don't understand your explanation on that.

Could you explain what you basically want to achieve? Explain the feature, not how you want to achieve it.

What's the problem with the many crane boom designs you can find on the web by the way?

Edited May 24, 2013 by Lipko

[Captain Coconut]

I think I understand the intent, but if you're using one worm gear as a rack and the other as a conventional worm gear that moves along the rack, the travel is still limited by the length of the "rack."

A worm gear sliding on an axle due to it being forced along it (as used in the autovalve in The Unofficial Technic Builder's Guide) is fundamentally different from causing the axle to slide on a constrained worm gear.

[Phantom59]

Have you thought of using 8 tooth gear on both upper and lower instead of the worm gear . I sometime find the 8 tooth gears quit loose on the axle.

Edited May 24, 2013 by Phantom59

[SNIPE]

I don't understand what you want to achieve and if the proposed or your solutions work or not.

What do you want? To slide the yellow axle by rotating the red one?

Have you tried your/others' solution with real bricks?

Does it work or not?

Is the yellow worm gear supposed to substitute the gear rack?

What's the problem with gear racks? I don't understand your explanation on that.

Could you explain what you basically want to achieve? Explain the feature, not how you want to achieve it.

What's the problem with the many crane boom designs you can find on the web by the way?

Hi,

I want the red axle to spin only as well as the red worm gear, the yellow axle should rotate with the yellow worm gear

The goal is to have the yellow axle and worm gear move out but as the yellow worm gear gets so far it needs to return back without pulling the axle back too, then it starts over again and so on.

Or the blue parts and both worm gears can slide up as one thing but this means having stoppers on the axles and I'm not sure how this would be built

Yes I've tried real lego parts, with mixed results, sometimes the axle and gear moved sometimes they both did and maybe sometimes just the axle moved some what. maybe I was holding it by the worm gears.

The image above wont really do anything because the worm gears will try to move apart but the blue parts are clamped together by bushes and both worm gears and the blue parts wont move as a whole either because the axle isn't threaded or anything.

I can stop one axle from spinning by connecting it to the spinning yellow axle but put a guide on it that keeps it actuating but not rotating.

Edited May 24, 2013 by SNIPE