Subject:
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Re: Chain Precession Drive - Courtesy of TechnicBRICKs
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Newsgroups:
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lugnet.technic
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Date:
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Mon, 23 Mar 2009 20:03:20 GMT
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Viewed:
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24478 times
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In lugnet.technic, William Leue wrote:
> Owen and Mike,
> The 2825 part connects the input shift with the orbiter. The part that was shown
> in the original LDRAW model clearly does not work because all its holes are
> round and so there is no way of transferring torque to the orbiter body. The
> 2825 part has a cross hole at one end, which takes the drive axle, and one at
> the opposite end, which takes the axle 2 slotted, which in turn is mated to the
> Technic bushing and forms the orbiter itself.
>
> I discovered this when I tried to build an actual physical model from the LDRAW
> model and discovered the problem, so I am quite confident that the LDRAW model
> is incorrect as shown.
>
> -Bill
>
> > > Bill.
> > >
> > > Perhaps you could elaborate on that a little? I can't see that part working
> > > there at all - the 2825 part has crosses at both ends, and you need the axle
> > > attached to the gear to be able to rotate freely.
> > >
> > > Owen.
> >
> > Apologies for not having part numbers to hand..
> >
> > You did mean the 1x5 not the 1x4 liftarm? if so Owen is right the cog must turn
> > freely hence the excessive 1x5 liftarm. I would be interested to see if you have
> > a working redesign...
> >
> > If you meant to replace the '1x4 liftarm' and a 'bush' with the '1x4 liftarm
> > with boss' and a 'half bush' then you will have a clearance issue with the cog
> > teeth. The bush is the only part that will clear the teeth and keep the correct
> > tension for clearing 4 teeth per turn, if you use just an axle the tension is
> > inadequate and you may clear either 3 or 4 teeth per turn making it a bit
> > random..
> >
> > I have built a 6:1 ratio drive around a 24 tooth gear this uses a 1x3 liftarm
> > and a 1x4 liftarm (again offset for the smooth hole) this uses just an axle (no
> > bush) for the correct tension.
> >
> > Regards
> >
> > Mike
Only the input side of the orbiter is connected to a shaft (via 1x4 liftarm) the
output shaft turns freely (via 1x5 liftarm) inside the orbiter and connects to
the Cog Only.
It should be as shown here:
http://www.brickshelf.com/cgi-bin/gallery.cgi?f=297233
I dont have Ldraw installed on this pc at the moment I could you confirm if it
is different to these picture instructions.
Regards,
Mike
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Message has 1 Reply:
 | | Re: Chain Precession Drive - Courtesy of TechnicBRICKs
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| (...) I agree: the input side is connected to the orbiter; the output shaft connects only to the cog. That is exactly the way mine is built. Where I disagree with the LDRAW file is the nature of the liftarm: what is shown is a 1x5 liftarm with only (...) (16 years ago, 23-Mar-09, to lugnet.technic)
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Message is in Reply To:
| | Re: Chain Precession Drive - Courtesy of TechnicBRICKs
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| Owen and Mike, The 2825 part connects the input shift with the orbiter. The part that was shown in the original LDRAW model clearly does not work because all its holes are round and so there is no way of transferring torque to the orbiter body. The (...) (16 years ago, 23-Mar-09, to lugnet.technic)
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