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Subject: 
Re: Chain Precession Drive - Courtesy of TechnicBRICKs
Newsgroups: 
lugnet.technic
Date: 
Mon, 23 Mar 2009 19:46:45 GMT
Viewed: 
23203 times
  
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



Message has 1 Reply:
  Re: Chain Precession Drive - Courtesy of TechnicBRICKs
 
(...) 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: (URL) dont have Ldraw installed on this (...) (15 years ago, 23-Mar-09, to lugnet.technic)

Message is in Reply To:
  Re: Chain Precession Drive - Courtesy of TechnicBRICKs
 
(...) 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 (...) (15 years ago, 23-Mar-09, to lugnet.technic)

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