LEGO TECHNIC : 4481


Technic / 4481	4480 \| 4482

Subject:	Re: I wish Lego made an "Anti-Backlash Gear"
Newsgroups:	lugnet.robotics, lugnet.technic
Date:	Thu, 5 Apr 2001 05:16:40 GMT
Viewed:	200 times

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! In lugnet.robotics, Thomas D. Fulk, Jr. writes: > > > > 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? > > > > 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. Drive or driven, you > choose. result is the same. S2 represents the other shaft in our > gear train. G1and G2 are 2 separate gears on S1, and they are both > in mesh with G3 which is located on S2. G2 is not splined to S1 like > G1 is, and is only there to act with the spring to remove the lash. > > Now.... Our first gear is actually 2 thin gears (G1 and G2) > together on the same shaft (S1), working as 1 gear... mating to a > single thicker gear (G3) with a torsional spring force causing G1 and > G2 to rotate in opposing directions, except the teeth of G3 stop them > from rotating more than the lash between the G1/G2 pair and G3. > Really the G1/G2 pair is acting a variable pitch gear that perfectly > mates to G3 at all times. > > If the force required to move the load is more than the spring > force between G1 and G2 there can be lash in this setup. In the > real-world application where I have seen this used (Toyota 3.4 V6 > engine, to mate the two camshafts located in each cylinder head) there > is a way to lock G1 and G2 together before you separate them from G3. > I assume this is because the spring is so strong that it would be hard > to rewind in the field. > > Thomas > > > > > > > > > > > >

Message has 1 Reply:

		Re: I wish Lego made an "Anti-Backlash Gear"
(...) 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 (...) (24 years ago, 5-Apr-01, to lugnet.robotics, lugnet.technic)

Message is in Reply To:

		Re: I wish Lego made an "Anti-Backlash Gear"
(...) 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. (...) (24 years ago, 5-Apr-01, to lugnet.robotics, lugnet.technic)

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