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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?
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Isnt that the same as the white clutch gear. Here is a link to it:
http://w3.one.net/~hughesj/technica/registry/gear/gear_3.html
Ram
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?
>
>
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Ram Meenakshisundaram wrote:
> Isnt that the same as the white clutch gear. Here is a link to it:
> http://w3.one.net/~hughesj/technica/registry/gear/gear_3.html
Maybe I'm just clueless, but I've yet to figure out what
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 finally figure out what the differential
gear really was, and I'm still trying to figure out the best
way top operate the brick seperator. Didn't even know what it
was until I saw it named in a catalog.
> Ram
Chris - Xenon
--
Chris Hanson | Xenon@3DNature.com | I've got friends in low latitudes!
New WCS 5 Demo Version! http://www.3DNature.com/demo/
"There is no Truth. There is only Perception. To Perceive is to Exist." - Xen
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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 operable force applied before the clutch disengages. Nano
Centemeter of force. In short I used one in each hand of the Robot I am
building, after gearing the the motor 1 or two "steps" (8 to 24 tooth) I
then inserted the Torque gear, and ran the axle straight to a worm gear
assymbly, the hand closes with a good deal of force, then when the fingers
reach the thunb, the force is greater then the presecribed limits then the
gear starts to slip and thus preventing damage to the structure.
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=39790
They are really very handy if you can gear them for the proper application.
In lugnet.robotics, xenon@3dnature.com writes:
> Ram Meenakshisundaram wrote:
>
> > Isnt that the same as the white clutch gear. Here is a link to it:
> > http://w3.one.net/~hughesj/technica/registry/gear/gear_3.html
>
> Maybe I'm just clueless, but I've yet to figure out what
> 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 finally figure out what the differential
> gear really was, and I'm still trying to figure out the best
> way top operate the brick seperator. Didn't even know what it
> was until I saw it named in a catalog.
>
> > Ram
>
> Chris - Xenon
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Eric Sophie wrote:
>
> 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 operable force applied before the clutch disengages. Nano
> Centemeter of force.
(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).
> They are really very handy if you can gear them for the proper application.
That's true - but I find they are almost always WAY too stiff for the
applications I have - by the time they've started to slip, the motor
has usually stalled - or ripped the robot to bits.
--
Steve Baker HomeEmail: <sjbaker1@airmail.net>
WorkEmail: <sjbaker@link.com>
HomePage : http://web2.airmail.net/sjbaker1
Projects : http://plib.sourceforge.net
http://tuxaqfh.sourceforge.net
http://tuxkart.sourceforge.net
http://prettypoly.sourceforge.net
http://freeglut.sourceforge.net
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Steve Baker wrote:
>
> I find they are almost always WAY too stiff for the
> applications I have - by the time they've started to slip, the motor
> has usually stalled - or ripped the robot to bits.
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.
--
Regards
Micah J. Mabelitini - LUGNET #918
The University of Kentucky
SECC Middlesboro Academic Skills Resource Center
accutron@kih.net - http://www.users.kih.net/~micahx/
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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 mechanical failure, System controll being the supervisor (RXC)
Eric
In lugnet.robotics, Micah J. Mabelitini writes:
> Steve Baker wrote:
> >
> > I find they are almost always WAY too stiff for the
> > applications I have - by the time they've started to slip, the motor
> > has usually stalled - or ripped the robot to bits.
>
>
> 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.
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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 a touch sensor in the thumb inorder to reverse
directions automatically, but the gear works so well, I often just rely on
timming, when using the Arm in an unofficial testing manner....Eric
In lugnet.robotics, sjbaker1@airmail.net writes:
> Eric Sophie wrote:
> >
> > 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 operable force applied before the clutch disengages. Nano
> > Centemeter of force.
>
> (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).
>
> > They are really very handy if you can gear them for the proper application.
>
> That's true - but I find they are almost always WAY too stiff for the
> applications I have - by the time they've started to slip, the motor
> has usually stalled - or ripped the robot to bits.
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"Eric Sophie" <Legomaster@gobi.com> wrote in message
news:GB91vJ.21x@lugnet.com...
> 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
Ncm.
> the range of operable force applied before the clutch disengages. Nano
> Centemeter of force. In short I used one in each hand of the Robot I am
Newtons x cm. Not nano. :)
Iain (the metric pissant)
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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?
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
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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!
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
>
>
>
>
>
>
>
>
>
>
>
>
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In lugnet.robotics, Eric Sophie writes:
> 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!
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 gears and the fourth would have to be the one with the
hole that's free to spin. slip the driving ring piece (I have two from the
space shuttle) into the open side of the free wheeling gear and then attach
the driving ring to it's shaft utilizing a rubber band connected to a part
fixed to the shaft. This will mean the gear with the hole will exert a force
on one of the gears on the opposite shaft, combined with the forces from the
meshing of the third and fourth gears there wil be no play between the two
shaft's.
This only works for two shaft's at a time.
Steve
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Steven Lane wrote:
> In lugnet.robotics, Eric Sophie writes:
>
> > 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!
>
> 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
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
>
--
MIME ATTACHMENTS DISCARDED:
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cool idea.....
In lugnet.robotics, Andy Gombos writes:
> Steven Lane wrote:
>
> > In lugnet.robotics, Eric Sophie writes:
>
> >
> > > 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!
> >
> > 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
>
>
> 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
>
> >
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Hmmm...
In lugnet.robotics, Steve Lane writes:
> In lugnet.robotics, Eric Sophie writes:
>
> > 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!
>
> 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 gears and the fourth would have to be the one with the
> hole that's free to spin. slip the driving ring piece (I have two from the
> space shuttle) into the open side of the free wheeling gear and then attach
> the driving ring to it's shaft utilizing a rubber band connected to a part
> fixed to the shaft. This will mean the gear with the hole will exert a force
> on one of the gears on the opposite shaft, combined with the forces from the
> meshing of the third and fourth gears there wil be no play between the two
> shaft's.
>
> This only works for two shaft's at a time.
>
> Steve
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In lugnet.robotics, Eric Sophie writes:
> Hmmm...
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 of gears of a different size in order to gear up or down.
Steve
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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 effects. So I will stick with it until Lego
evolution catches up. In turn I stll want Stonger tolerences from Axles and
motors. Fine Mesh Grears. Wait what year is it again? 2085?
In lugnet.robotics, Steve Lane writes:
> In lugnet.robotics, Eric Sophie writes:
> > Hmmm...
>
> 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 of gears of a different size in order to gear up or down.
>
> Steve
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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 becomes 'different', in that connected gears run
the same (not opposite) directions.
Also, the chain is beautifully made. When I show it to people, they don't
want to give it back. They want to play with it...!
Regards, Jerry
In lugnet.robotics, Eric Sophie writes:
> 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 effects. So I will stick with it until Lego
> evolution catches up. In turn I stll want Stonger tolerences from Axles and
> motors. Fine Mesh Grears. Wait what year is it again? 2085?
>
> In lugnet.robotics, Steve Lane writes:
> > In lugnet.robotics, Eric Sophie writes:
> > > Hmmm...
> >
> > 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 of gears of a different size in order to gear up or down.
> >
> > Steve
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In lugnet.robotics, Jerry Kalpin writes:
> 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 becomes 'different', in that connected gears run
> the same (not opposite) directions.
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 quite a bit of chain slack.
> Also, the chain is beautifully made. When I show it to people, they don't
> want to give it back. They want to play with it...!
With this I fully agree.
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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 gears mesh. Someone will do that for chain, someday.
There's another thing you should have mentioned: The less chain slack the
greater the force between shafts and associated friction.
Regards, Jerry
>
> 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 quite a bit of chain slack.
>
> > Also, the chain is beautifully made. When I show it to people, they don't
> > want to give it back. They want to play with it...!
>
> With this I fully agree.
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In lugnet.robotics, Jerry Kalpin writes:
> 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 gears mesh. Someone will do that for chain, someday.
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 up some sort of chain tensioner.
> There's another thing you should have mentioned: The less chain slack the
> greater the force between shafts and associated friction.
As far as I know, all the available techniques for taking the play out of a
drive train sacrifice efficiency when doing so. The more sophisticated just
do so to a lesser degree. I agree with you that this is really noticable
with a chain. Especially when the load is great enough that shafts start to
bend and the sprockes no longer reside in the same plane.
It's really hard for me to fault Lego for the sloppy mesh of their gears.
Not when you consider their per unit price. I imagine that some of the slop
is intentional for purposes of reducing friction. We are working with puny
little motors after all. If you wan't to limit backlash, just use the big
gears and remember it is a building "toy".
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> It's really hard for me to fault Lego for the sloppy mesh of their gears.
> Not when you consider their per unit price. I imagine that some
> of the slop
> is intentional for purposes of reducing friction. We are working
> with puny
> little motors after all. If you wan't to limit backlash, just use the big
> gears and remember it is a building "toy".
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 gear backlash, but also with joiners that have play (or
wiggle), and axles that can be twisted and bend easily. Take the Silver
Champion Technic set for example. Hold one front wheel tight, and see how
far you can turn the other one. Without using too much force, you can turn
it 45 degrees! You can also tilt it at least 20 degrees! It doesn't really
need a suspension!
There are construction systems out there that are much better suited for
mechanical constructions. Fishertechnik is an example. The Mondo-tronics's
Robot Store (http://www.robotstore.com) carries some sets in the U.S.
Fischertechnik uses solid metal axles, and in general is much stronger, with
no flexing and bending. But Fischertechnik doesn't have the large market
share that Lego enjoys, and therefore, it's much more expensive. And there
are no mini-figs, Silver Champions, cool trains, etc. Go to
http://www.fischertechnik.de for full details. The site has a checkbox to
switch to English.
Tilman
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Listen guys, I'm not playing around with a "Building toy" here,
look,
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=39692
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=37892
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=27109
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=39789
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=39790
When working - creating on this scale, you begin to demand the highest
preformance from all aspects of Lego.
Eric "Legomaster" Sophie
In lugnet.robotics, "Tilman Sporkert" <tilman@webmethods.com> writes:
> > It's really hard for me to fault Lego for the sloppy mesh of their gears.
> > Not when you consider their per unit price. I imagine that some
> > of the slop
> > is intentional for purposes of reducing friction. We are working
> > with puny
> > little motors after all. If you wan't to limit backlash, just use the big
> > gears and remember it is a building "toy".
>
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In lugnet.robotics, Eric Sophie writes:
> Listen guys, I'm not playing around with a "Building toy" here,
>
> look,
> When working - creating on this scale, you begin to demand the highest
> preformance from all aspects of Lego.
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 8 stud technic beams, and two 8 stud
technic rods. Mesh two of the 48 tooth gears by sliding them onto the rods,
and inserting the rods into the holes of one of the beams. Slide the second
beam over the other end of the rods and attach the remaining gears to the
open end of the rods. If everything is aligned properly, the gears will
rotate freely, and there will be a little bit of play. While the gears on
one side are meshed, disengage one of the gears on the otherside, rotate it
one tooth, and reengage. The gears no longer rotate as freely, but there is
no longer any backlash. Slip 3 or 4 teeth and the gear train begins to get
really stiff.
Nothing too brilliant, but it does the job. Probably not all that original
either, but it just occurred to me.
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Rrrrrrrrr.....
In lugnet.robotics, Dean Hystad writes:
> In lugnet.robotics, Eric Sophie writes:
> > Listen guys, I'm not playing around with a "Building toy" here,
> >
> > look,
>
> > When working - creating on this scale, you begin to demand the highest
> > preformance from all aspects of Lego.
>
> 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 8 stud technic beams, and two 8 stud
> technic rods. Mesh two of the 48 tooth gears by sliding them onto the rods,
> and inserting the rods into the holes of one of the beams. Slide the second
> beam over the other end of the rods and attach the remaining gears to the
> open end of the rods. If everything is aligned properly, the gears will
> rotate freely, and there will be a little bit of play. While the gears on
> one side are meshed, disengage one of the gears on the otherside, rotate it
> one tooth, and reengage. The gears no longer rotate as freely, but there is
> no longer any backlash. Slip 3 or 4 teeth and the gear train begins to get
> really stiff.
>
> Nothing too brilliant, but it does the job. Probably not all that original
> either, but it just occurred to me.
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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 special connections to local electrical
substations. When the creation is cool, it is referred to as a "toy". A
"machine" is a boring thing which does not stir the soul.
So once again I say of your inventions. Those are really cool toys! Take
it in the spirit it was given.
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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 toys. etc....
Recv'd in the manner it was given.
I thank you.
Eric
In lugnet.robotics, Dean Hystad writes:
> 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 special connections to local electrical
> substations. When the creation is cool, it is referred to as a "toy". A
> "machine" is a boring thing which does not stir the soul.
>
> So once again I say of your inventions. Those are really cool toys! Take
> it in the spirit it was given.
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In lugnet.robotics, Eric Sophie writes:
> Rrrrrrrrr.....
>
> >
> > Nothing too brilliant, but it does the job. Probably not all that original
> > either, but it just occurred to me.
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 I suppose I am going to have to model a DDG 280's gearbox out of lego
as penance?
James
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Good luck!!!
> 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 I suppose I am going to have to model a DDG 280's gearbox out of lego
> as penance?
>
> James
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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 quite a bit of chain slack.
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 rubber band or spring based solution. It still will have some backlash,
but much less than a normal construction.
James
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Jerry Kalpin wrote:
> Also, the chain is beautifully made. When I show it to people, they don't
> want to give it back. They want to play with it...!
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
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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.
http://bobfay.users5.50megs.com/newmill.htm
I have tried using a second motor in the gear train with a slight reverse
current. This pretty bulky.
I think the gear you want is a sandwich of two gears that are spring loaded
so the teeth oppose each other. This would work in a small gear train.
There is another example of the conical gear at the end of this page.
http://bobfay.users5.50megs.com/speedy.htm
--
Bob Fay
rfay@we.mediaone.net
http://bobfay.users5.50megs.com/index.html
http://www.geocities.com/Heartland/Bluffs/7900/
"Eric Sophie" <Legomaster@gobi.com> wrote in message
news:GB7x2F.J0G@lugnet.com...
> Tech question for us: Any body know what an Anti-Backlash gear is?
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Whoa, I gotta think about this one for awhile.....
In lugnet.robotics, Robert Fay writes:
> 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.
> http://bobfay.users5.50megs.com/newmill.htm
>
> I have tried using a second motor in the gear train with a slight reverse
> current. This pretty bulky.
>
> I think the gear you want is a sandwich of two gears that are spring loaded
> so the teeth oppose each other. This would work in a small gear train.
>
> There is another example of the conical gear at the end of this page.
> http://bobfay.users5.50megs.com/speedy.htm
> --
> Bob Fay
> rfay@we.mediaone.net
>
> http://bobfay.users5.50megs.com/index.html
> http://www.geocities.com/Heartland/Bluffs/7900/
> "Eric Sophie" <Legomaster@gobi.com> wrote in message
> news:GB7x2F.J0G@lugnet.com...
> > Tech question for us: Any body know what an Anti-Backlash gear is?
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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 does make it much easier to do this trick with out
breaking LEGO(R) parts though : )
HTH,
Xanthra47
"Bob Fay" <rfay@we.mediaone.net> wrote in message
news:GB7y67.LCK@lugnet.com...
> 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.
> http://bobfay.users5.50megs.com/newmill.htm
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Bob Fay wrote:
> 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.
> http://bobfay.users5.50megs.com/newmill.htm
>
> I have tried using a second motor in the gear train with a slight reverse
> current. This pretty bulky.
>
> I think the gear you want is a sandwich of two gears that are spring loaded
> so the teeth oppose each other. This would work in a small gear train.
>
> There is another example of the conical gear at the end of this page.
> http://bobfay.users5.50megs.com/speedy.htm
> --
> Bob Fay
> rfay@we.mediaone.net
>
> http://bobfay.users5.50megs.com/index.html
> http://www.geocities.com/Heartland/Bluffs/7900/
> "Eric Sophie" <Legomaster@gobi.com> wrote in message
> news:GB7x2F.J0G@lugnet.com...
> > Tech question for us: Any body know what an Anti-Backlash gear is?
What set(s) include this "conical" gear?
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In lugnet.robotics, Jonathan Wilson writes:
> What set(s) include this "conical" gear?
Far as I can tell, these are the gears used in the gearboxes in 8880, 8448,
8480, and prob'ly others.
ROSCO
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