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Subject: 
Re: How do I...
Newsgroups: 
lugnet.technic
Date: 
Sun, 2 Apr 2000 16:47:28 GMT
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Well, Nicky, it kinda depends on how many gears you are thinking of when
you say 'and so on...'.  I can think of a couple of solutions to this
problem, none of them very compact or tidy. If you wanted to turn a large
number of gears (or other rotary elements) half-way, or some other fraction
of a turn in one direction, or back, then you could put together a linar
indexing carriage which moves along a series of stations. At each station,
the carriage engages the rotary elment and gives it the requisite twist,
using a rotation detector or limit switches to determine when the right
amount of twist has taken place. I have been working on something similar
for a Mindstorms Turing Machine idea I have.

I have also come up with a list of challenges for Technic designers. These
are standard mechanisms that I think will be difficult to implement using the
current available elements.  The best solutions, IMHO, would be purely
mechanical, with no RCX or other digital intelligence doing the hard
work. Any takers?

1. An odometer. This is a set of wheels of some kind, where the fastest-turning
wheel advances the next-fastest-turning wheel by some fraction of a
revolution for each revolution that the fastest-turning wheel makes. The
next wheel does the same for the next-slower turning wheel, etc., etc. for
any number of wheels.

2. A washing machine transmission, that would do both the "wash cycle", where
the impeller turns back and forth smoothly, and the "spin cycle", where the
impeller and basket turn quickly.

3. A reliable 2-state toggle, where the EXACT SAME MOTION will repeatedly
cycle some element into one of two states. Think of a push button switch,
where the same motion (a push) cycles the switch ON, OFF, ON, OFF,... etc.
However, this would want to be purely mechanical, and relatively compact.

I would love to see Lego come out with some "advanced Technic" parts, e.g.:

a. A set of planetary gears or other hypocycloid gears.
b. a fluid clutch or other fluid coupling.
c. A really good way of building 3D space frames, a la K'Nex or some of the
other building systems.  Actually, all we really need is some Lego-to-K'Nex
adaptors!
d. A decent escapement mechanism. The things that people have been building
are ingenious but basically hideous, IMHO.
e. Better elements for linear motion. The gearset is OK for rotary motion,
but the options for linear motion are limited.

-Bill Leue

In lugnet.technic, Nicky Bishop writes:
Does any one ahave an idea on how I could turn a gear half way, then that one
stops, and another one goes around halfway, and so on, all with one motor? I
see I could remove the teeth off part of the gears, but I'd really rater not.



Message has 4 Replies:
  Re: How do I...
 
(...) Don't go there.... check out ZNAP (100 % LEGO) instead. It has been available in Europe for a while and I hear it is starting to appear at US TRUs... You can build quite big things. Not quite as flexible as K'Nex but faster to build large (...) (24 years ago, 2-Apr-00, to lugnet.technic)  
  Clarification
 
(...) What I ment when I said "and so on" was that the first gear would go halfway, then the 2nd, then the first, then the 2nd and so on. Sorry for not making that clear. (24 years ago, 2-Apr-00, to lugnet.technic)
  Re: How do I...
 
(...) I'm working on a clock which uses a 6 tooth escapement made from 6 of the new quarter-oval brackets. The short sides of the brackets are pinned to a hub made of medium pulleys. It's a bit hard to get the spacing of the little ratchet mechanism (...) (24 years ago, 3-Apr-00, to lugnet.technic)  
  Re: How do I...
 
wleue1@nycap.rr.com (William M. Leue) wrote in <FsEEn4.Cx2@lugnet.com>: (...) One thing I've thought about several times is how to build a pure LEGO MOC which can't be taken apart without damaging pieces. I have some ideas on how to build a latch (...) (24 years ago, 4-Apr-00, to lugnet.technic)  

Message is in Reply To:
  How do I...
 
Does any one ahave an idea on how I could turn a gear half way, then that one stops, and another one goes around halfway, and so on, all with one motor? I see I could remove the teeth off part of the gears, but I'd really rater not. (24 years ago, 2-Apr-00, to lugnet.technic)  

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