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Eric Sophie wrote:
> 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 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
the center
0.3" outer diameter. These can be placed behind bevel gears to improve the mesh
and get less backlash.
In the case of the rectagular blocks which are worm gear boxes, you can
trap one
of these washers at one end of the worm. This reduces slop in the worm position
and really improves the resultant output shaft firmness.
In simple mechanisms like scanning devices, try loading the drive train
with a rubber
band. This will keep all the teeth meshing biased and increase the accuracy at
the expense of maximum torque of course.
JB
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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 jokingly, ....Cheater!!!
You experimented (cheated) with washers of a sort, gaaa..
Pardon my Lego purism. I too have tried to use series 1 bevel gears in
different ways ,, but it never made up for the fact that TLC's worm gear is
short! in fact when I was able to get a measure of "shimming" the resultant
distance of the axle cause a bowing effect when a heavy load was placed on
the drive gear and the connection would skip....
Make that a longer Worm gear and an anti-backlash gear to go Please Thank
you TLC
Eric Sophie
In lugnet.robotics, John Barnes writes:
> Eric Sophie wrote:
>
> > 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 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
> the center
> 0.3" outer diameter. These can be placed behind bevel gears to improve the mesh
> and get less backlash.
>
> In the case of the rectagular blocks which are worm gear boxes, you can
> trap one
> of these washers at one end of the worm. This reduces slop in the worm position
> and really improves the resultant output shaft firmness.
>
> In simple mechanisms like scanning devices, try loading the drive train
> with a rubber
> band. This will keep all the teeth meshing biased and increase the accuracy at
> the expense of maximum torque of course.
>
> JB
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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 this model came out of that official Lego box! Ok, so I used some
of the packaging :)
JB
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Ha Ha that's great...ok buddy, thanks... Eric,
- I still have got to ponder these pix for awhile!
In lugnet.robotics, John Barnes writes:
>
> 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 this model came out of that official Lego box! Ok, so I used some
> of the packaging :)
>
> JB
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