How can I lock effectly a stepless dividing apparatus

[kindoo]

hi all,
Just as the topic, I'm thinking a stepless dividing apparatus, for must be stepless, I couldn't lock it by tooth plate such as end-gear, so what machenism can do it?
I thought, perhaps I can do a pair of conical surface to realize it, does anyone has done the method? any suggestion will be welcome, thanks first!

 

[Danger]

Welcome to PF, Kindoo.
With no offense intended, your question makes no sense to me. I don't recognize any of the terms that you used. Can you be more descriptive of what you need to achieve?

 

[kindoo]

thanks danger,
perhaps my english is too pool, specially, my mechanical technology words so few.
I want to do a mechanism what can divide at any degree, and can be lock at the site where I can do some drilling or milling work!
for example, here is a ring, 11 or 12 or 13 or 14 or any other holes local whole circle, I want do these any hole freely. I thought it must has some classical structure, but how is it? can you help me? hoho. thanks.

 

[Danger]

Okay, I think that I understand you now. If so, what you want is essentially a protractor. The easiest way to accomplish it which immediately comes to mind is to have a disk marked in degrees, with a flat bar pivoted from the centre. A thumbscrew threaded through the bar can impinge upon the disk to lock the position.

 

[berkeman]

I googled stepless dividing apparatus, and got a couple hits, but no pictures yet.

http://www.chemyq.com/patentfmen/pt53/527027_8F033.htm

Is this what you mean kindoo? If you could post some links to pictures of typical machines like you are talking about, that would help us greatly.

 

[kindoo]

hi Danger and berkeman, thanks first for your help,
of course Danger, the structure what you descript is just simple and can do some what I want, but, I want better, for In fact, I need place something one the plate can be divided stepless, perhaps the something on the plate has some weight.
and berkeman, thanks, you provide a patent structure, and it must be a flexible mechanism, but it seem be controlled by electromagnetic and be driven by compressed air, I guess, it must be designed for some light usage.
I have a structure what I image myself, here is its figure, can you help me to verify it or do some simulating on computer?

PS, what CAD/CAE software do you using? I use solidword and acad for these, but it seem poor.

 

[kindoo]

http://www.jinzi-china.com/aaa.jpg
here is the picture of my structure, the first is base board, the second is worm shaft, the third is working plate and worm gear, the forth is locking corn, when would divide, release the locking corn, and driving wormshaft to push worm gear do an any degree, once the dividing action end, pull the locking corn to lock the plate, how do you consider it, can it lock effectly?

 

[Danger]

It certainly is refreshing to see such a professional illustration. It defines your intent very clearly.
The design itself seems to be simple, effective, and reliable. As long as the machining tolerances are tight, it should work beautifully. Would you be using friction material (such as is used on a brake pad) on the locking 'corn', or relying solely upon the wedge effect? Either way, it looks good.

 

[kindoo]

Danger, hoho
the structure what show in picture seem be a good idea, but I don't verify.
I no idea how to keep the plate current location when the cone was released and locked (I do a spelling mistake on 'cone' :), do anyone have some idea?

 

[Danger]

The worm gear alone will provide locking when not being driven. The cone will merely eliminate any 'slop' in the gearing. If your accuracy requirements aren't too high, you can get rid of it entirely.
I don't know if that covers your question or not; I'm still experiencing a language barrier.

 

[kindoo]

hi Danger, sorry my English is so poor :(
you mentioned the key of this problem, accuracy requirements, just I want a high accuracy, but I don't make sure, I want do accuracy +/-0.05mm, at diameter 1.6mm, I thought must have some successful and classical structure to resolve this question, but I can not find it! Now, I can only do some to avoid clearance between worm gear for getting more high accuracy, what idea do you have?

 

[Danger]

Oh, wow! I was thinking several orders of magnitude off-scale. Your mention of drilling and milling gave me the impression of something that would be used in a standard machine shop—maybe 20cm or so in diameter. It sounds as if you need a watch-maker. I'm afraid that I have no ideas at the moment, but I'll keep thinking about it.
Don't worry about your English. For a second language, you handle it well. It presents a bit of a challenge, but not an insurmountable one.

 

[kindoo]

haha, thanks Danger, It surely be used in factory environment, I found here is a physics forums, is here talking about machine only for laboratory or verify some theory? of course, here is an interesting site, where I can find many different subject. and do you know any other special forums for mechanical engineers?
I thought I must do some try to realize what I want on the stepless dividing apparatus :)