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Tech question for us: Any body know what an Anti-Backlash gear is? If Lego made one, we would all have super precise Robots and mechanisisms! BERG carries them... Anybody know what I'm talking about? (23 years ago, 3-Apr-01, to lugnet.robotics, lugnet.technic)
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Isnt that the same as the white clutch gear. Here is a link to it: (...) (23 years ago, 3-Apr-01, to lugnet.robotics, lugnet.technic)
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The closest thing to an anti-backlash gear is the Conical gear (a misnomer). It can be used to load a gear train. I have used this in a design by Iain Hendry. (URL) have tried using a second motor in the gear train with a slight reverse current. (...) (23 years ago, 3-Apr-01, to lugnet.robotics, lugnet.technic)
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(...) I have done quite a lot of experimentation to limit backlash in certain situations. First of all, it is quite easy to make little shims from the yellow plastic material the parts are seperated into in new sets. I make ones with 0.2" holes in (...) (23 years ago, 3-Apr-01, to lugnet.robotics)
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Interesting point about the rubber bands vs the resultant torque loss, it is true that the opposing forces on the gears along with the "rubber pull" will tender them to one direction or another in concert... However,...and I say this kindly and (...) (23 years ago, 3-Apr-01, to lugnet.robotics)
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>>>>>> However,...and I say this kindly and jokingly, ....Cheater!!! You experimented (cheated) with washers of a sort, gaaa.. <<<<<< Hey! real engineering uses shims (not washers ;) And I can honestly put my hand on my heart and say everything in (...) (23 years ago, 3-Apr-01, to lugnet.robotics)
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Whoa, I gotta think about this one for awhile..... (...) (23 years ago, 3-Apr-01, to lugnet.robotics, lugnet.technic)
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(...) one would do with this. The Lego Mindstorms booklet doesn't explain it at all. (My host laptop computer runs Linux, and so if it is explained in the nifty multimedia CD-ROM that came with Mindstorms, I've missed it.) It took me weeks to (...) (23 years ago, 3-Apr-01, to lugnet.robotics)
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Ha Ha that's great...ok buddy, thanks... Eric, - I still have got to ponder these pix for awhile! (...) (23 years ago, 3-Apr-01, to lugnet.robotics)
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It's not so much the "conical" gear that takes the backlash out of the setup that Bob Fay provided links to, but the ability to use the technic axles as torsion springs and keep the gear teeth in the train loaded at all times. That particular gear (...) (23 years ago, 4-Apr-01, to lugnet.robotics, lugnet.technic)
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(...) What set(s) include this "conical" gear? (23 years ago, 4-Apr-01, to lugnet.robotics, lugnet.technic)
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The CD-Rom does not explaiin how to use this piece, but in an earlier post I wrote: Ok, this is called a "Slip Gear" or "Torque Gear" It is used to prevent over rotation by means of an internal clutch, the 2.5 - 5.0 NCM I belive means the range of (...) (23 years ago, 4-Apr-01, to lugnet.robotics)
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(...) Far as I can tell, these are the gears used in the gearboxes in 8880, 8448, 8480, and prob'ly others. ROSCO (23 years ago, 4-Apr-01, to lugnet.robotics, lugnet.technic)
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(...) (I think we established that this is Newton centimeters - a force of between two and a half and five Newtons applied at a distance of one centimeter will cause the gear to slip...or half that at 2cm, a third at 3cm and so on). (...) That's (...) (23 years ago, 4-Apr-01, to lugnet.robotics)
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(...) Hmm interesting. I only have one clutch gear (the one that came with RIS 1.5), and it is too *loose* to really be at all functional. I've also read that the clutch force tends to drop in them the more they are used. (23 years ago, 4-Apr-01, to lugnet.robotics)
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Oh , right , Newtons , I was saying Nano centameters! thanks....I guess you need a fair amount of gearing and distance to use these gears effectivly along with opposing resistance, I love the way it works in the hand I developed, infact in included (...) (23 years ago, 4-Apr-01, to lugnet.robotics)
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Yes they do lose a little, I guess we always knew that would be the case, I hate to see you not use the gear if it's to loose, reurn it for a new one if you decide somthing really needs it. Also I consider this gear a "back-up" in preventing (...) (23 years ago, 4-Apr-01, to lugnet.robotics)
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"Eric Sophie" <Legomaster@gobi.com> wrote in message news:GB91vJ.21x@lugnet.com... (...) over (...) Ncm. (...) Newtons x cm. Not nano. :) Iain (the metric pissant) (23 years ago, 4-Apr-01, to lugnet.robotics)
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(23 years ago, 4-Apr-01, to lugnet.robotics)
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(...) You can use those half beveled gears(with the recess) back to back as one gear, and one (maybe 2) crown gears as the gear on the other shaft. It depends on what the setup requires as of gear setup to work. Andy (...) (23 years ago, 4-Apr-01, to lugnet.robotics)
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(...) I know of 1 type of zero-lash/anti backlash geartrain. It's hard to put it in words but I'll try. My example assumes there are only 2 shafts but it can be applied to as many shafts as you need. In my example S1 represents our first shaft. (...) (23 years ago, 5-Apr-01, to lugnet.robotics, lugnet.technic)
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Interesting , but we need one for Lego! I do see what you are saying, and It is an interesting solution,, although a little hard to visualize...Thanks! (...) (23 years ago, 5-Apr-01, to lugnet.robotics, lugnet.technic)
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(...) I was going to say this solution is easy, but then I tried it. There are only two shaft's in this example. As lego don't make don't make a 'double width gear' You'd have to use four to make it in lego. All you'd need is three normal 16 tooth (...) (23 years ago, 5-Apr-01, to lugnet.robotics, lugnet.technic)
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Hmmm... (...) (23 years ago, 5-Apr-01, to lugnet.robotics, lugnet.technic)
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(...) Explain 'Hmmm...' :-) I of course omitted the fact that my solution as described produces no mechanical advantage just a shaft going in the opposite direction. Of course, you can always replace the pair of gears on the second shaft with a pair (...) (23 years ago, 5-Apr-01, to lugnet.robotics, lugnet.technic)
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cool idea..... (...) (23 years ago, 5-Apr-01, to lugnet.robotics)
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As this discussion grows, I submit: (that) Part of the problem with Mechanical flex, Gear "Backlash" if you will, Derives from many aspects when we model maximun preformance from Axles, Gears, and all the elements combined to produce desired (...) (23 years ago, 5-Apr-01, to lugnet.robotics, lugnet.technic)
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There is one real simple way to eliminate backlash: Use LEGO's 'small-link chain' with their normal gears as sprockets. I paid CAN$7.00 for 135 links from Pitsco-Dacta's Canadian vendor. There is absolutely NO backlash. Mind you, the gearing problem (...) (23 years ago, 5-Apr-01, to lugnet.robotics, lugnet.technic)
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(...) You're kidding, right? It's almost impossible to build a geartrain using the chain that doesn't have tons of reversal delay. The links seem to be designed in such a way that they don't work well with technic beams and gears. I always have (...) (23 years ago, 5-Apr-01, to lugnet.robotics, lugnet.technic)
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Dean, it's probably dumb luck that the two drives on the piece I'm working on have little slack. Yet, with LEGO beams and blocks you can't use every gear combination; there are published beam/block/plate combinations that let this or that pair of (...) (23 years ago, 5-Apr-01, to lugnet.robotics, lugnet.technic)
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(...) If you use a tensioner arrangement, then it works OK. I haven't really played around with much more than simple weight tensioners (mostly for conveyer use...the catapilar treads are great for that!), but imagine you could come up with a (...) (23 years ago, 5-Apr-01, to lugnet.robotics, lugnet.technic)
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(...) Believe me that I have tried a lot of combinations. Also your and my idea of "little slack" may be quite different. But it is true that I have never done an exhaustive study on the subject. I usually just give up on getting it perfect and rig (...) (23 years ago, 5-Apr-01, to lugnet.robotics, lugnet.technic)
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(...) It's not the unit price, but the primary motivation for Lego products: It's a toy for kids. Yes, it has found some applications in education and amateur robotics, but it's still a toy. To build exact mechanisms, you not only have to deal with (...) (23 years ago, 6-Apr-01, to lugnet.robotics)
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Listen guys, I'm not playing around with a "Building toy" here, look, (URL) working - creating on this scale, you begin to demand the highest preformance from all aspects of Lego. Eric "Legomaster" Sophie (...) (23 years ago, 6-Apr-01, to lugnet.robotics)
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(...) Looks like toys to me. Really incredibly cool toys! Tilman's post supporting my "Toy" claim mentioned how torsionally flimsy the technic axles are. This could be used to take the backlash out of a gear train. Pull out four 48 tooth gears, two (...) (23 years ago, 6-Apr-01, to lugnet.robotics)
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(...) Yes, I've noticed this too - they like to run it through their fingers and make bracelets and whatnot from it. Perhaps it would be a good executive stress toy? :-) Jennifer Clark (23 years ago, 6-Apr-01, to lugnet.robotics, lugnet.technic)
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Rrrrrrrrr..... (...) (23 years ago, 9-Apr-01, to lugnet.robotics)
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Sorry Eric. I certainly didn't mean the word "toy" to be derrogetory in any way. Must be a cultural thing. My job is to create room sized "toys" which weigh several tons, contain thousands of kilowatts of potential and/or kinetic energy, and require (...) (23 years ago, 9-Apr-01, to lugnet.robotics)
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Mmmm, you are indeed respectful. Thanks, wow, So when we have made our masterpieces we sit back and enjoy our toys, for our mind, body and soul extensions. I like that! Very good. Man's gotta have his toys ya know. or The more money the bigger the (...) (23 years ago, 9-Apr-01, to lugnet.robotics)
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(...) Doh!. And I just took this in school (in fact, am going to write an exam which this will appear on (methinks) thisafternoon. It's called "Locked Train", and allows for more even power distribution across multiple gears in a gearbox. Hmm...Now (...) (23 years ago, 10-Apr-01, to lugnet.robotics)
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Good luck!!! (...) (23 years ago, 11-Apr-01, to lugnet.robotics)
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