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Subject: 
Re: Has anyone ever tried to design a washing machine mechanism?
Newsgroups: 
lugnet.technic
Date: 
Thu, 27 Jul 2000 12:21:28 GMT
Viewed: 
973 times
  
Ran Talbott <ran@netgate.net> wrote in message news:FyCpHp.A1D@lugnet.com...
In lugnet.technic, Geoffrey Hyde writes:

The bowl itself would either have to be a special piece of material not • made
out of LEGO or we'd have to wait until they produced one for us

Duplo set 2983 includes a barrel that's about 6 studs in diameter by 9 or • 10
high.   You'd need to drill the bottom for the agitator axle,  but I think
that's only a "venial" sin among purists,  compared to introducing a
"foreign element"  ;-)

Hmmm - what would I do with all the rest of the Duplo, though?  :o)  I'd
have enough trouble getting rid of it as it is ...

Other possibilities might be the 8- and 10-stud octagonal domes used in
various space and underwater models.

I had a closer look, and the ones in 6180 Hydro Search Sub have a cross-axle
shaped hole, and not a round one, meaning they'd rotate with the axle.  Not
good.  *blows theory into LEGO pieces*

I hope someone has tried at least the mechanism, it would be interesting • to
see how to design the rotational movement power for the washing tub • changing
to a cam-based movement

I think the agitator and the tub are concentric,  but separate, • mechanisms.
Iirc,  the tub on mine is stationary during the wash and rinse cycles,
letting the agitator do *all* the agitating work.

Well, they do rotate independently of each other if that's what you're
trying to say.  They also connect through the same axis, if that's also what
you're trying to say.  :-)

I think cams would be a key element somewhere in
this.

They could be:  it depends on how much the agitator actually rotates.

Something like around about 120-180 degrees or pretty close to that in a
real washing machine.  One of these days I might design a LEGO rotational
sensor hooked up to an agitator in a washing machine that will tell me.  ;-)

A possibility,  if you were willing to accept a limit of,  say,  120 • degrees
of rotation,  would be to put a fixed arm perpendicular to the agitator
axle (a pin in a 40-tooth gear might do this).  Then connect that arm to
something equivalent to the rod in a car engine.  At the other end of the • rod
would be either a car-like crankshaft,  or a reciprocating mechanism like • a
pneumatic cylinder.

That might work, but I think the real ones rotate further than that.  :o)

The net effect is to turn the reciprocating motion of the rod into partial
back-and-forth rotation of the agitator.  The travel of the recirprocating
mechanism has to be chosen to that it doesn't swing the agitator arm • through
too many degrees.  I picked 120 because it seemed fairly safe:  it
completely eliminates the risks of going full circle and of "lock-up" if
the two arms get parallel.  I *think* there's also a variation in the • amount
of leverage the reciprocating mechanism gets,  based on the angular
position of the arm attached to the agitator:  i.e.,  that arm looks like • a
varying-length lever to the reciprocator.  I'd have to try it to be sure,
but that's what my mental model feels like.

I picked cam, because it would appear that that is the way the gearbox
works.  There's not enough room for it to rotate a lever as well, I think.
It would be interesting to see an actual patent or technical drawing, and
find out what exactly they used in the mechanism.

Basically, what you'd have is a cam holding a set of gears eccentrically
around the central axis, and the motion of the gears drives it backwards and
forwards.  It might involve a pair of gears similar in makeup to a
deralleiur pair of gears as found on a multi-speed bicycle and something
(I'm theorizing here ...) out of the mechanism of a clock, but there would
appear to be a cam of sorts that forms one of the basic components of the
gearbox, and helps it drive the central spindle around in a back and forth
motion.

Cheers ...

Geoffrey Hyde



Message has 1 Reply:
  Re: Has anyone ever tried to design a washing machine mechanism?
 
(...) To get serious for a moment, there are probably dozens of places near you (assuming you're not on some remote sheep station, connecting via direct satellite link ;-) Day care centers, the nursery at your church, the pediatrics ward at your (...) (24 years ago, 28-Jul-00, to lugnet.technic)

Message is in Reply To:
  Re: Has anyone ever tried to design a washing machine mechanism?
 
(...) Duplo set 2983 includes a barrel that's about 6 studs in diameter by 9 or 10 high. You'd need to drill the bottom for the agitator axle, but I think that's only a "venial" sin among purists, compared to introducing a "foreign element" ;-) (...) (24 years ago, 27-Jul-00, to lugnet.technic)

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