LEGO TECHNIC : 4479


Technic / 4479	4478 \| 4480

Subject:	Re: I wish Lego made an "Anti-Backlash Gear"
Newsgroups:	lugnet.robotics, lugnet.technic
Date:	Thu, 5 Apr 2001 00:24:17 GMT
Viewed:	211 times

> 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"
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! (...) (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"
Isnt that the same as the white clutch gear. Here is a link to it: (...) (24 years ago, 3-Apr-01, to lugnet.robotics, lugnet.technic)

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