Subject:
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Re: A query to GBC members, module builders, and technic model builders.
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 28 Jan 2005 00:04:46 GMT
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Reply-To:
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Geoffrey Hyde <{gdothyde@}StopSpam{bigponddotnetdotau}>
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Viewed:
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2870 times
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"Mr S" <lego-robotics@crynwr.com> wrote in message
news:20050127152527.82125.qmail@web51507.mail.yahoo.com...
> --- Geoffrey Hyde <g.hyde@bigpond.net.au> wrote:
> > I've seen a lot of usage of the Technic Link Chain
> > and Technic Link Tread in
> > your models, and for those of you who use them, I'd
> > like to know how much
> > would you use of each type on average?
>
> I use the Technic chain to take the backlash out of
> gear trains, and to create gear trains in combinations
> that are not possible using only gears (due to spacing
> of the gears on beams etc.) Where one chain is not
> strong enough, clever designs allow for two chains. I
> have need for the creations to be very strong. The
> chains allow you to create drive mechanisms that
> simply are not possible with gears alone, such as
> across a distance without the middle gears and the
> backlash they introduce, or with gears spaced in ways
> that do not allow for gears to mesh. (inclusion of
> rotation sensors to my drive train was simplified by
> the use of chain links as the rotation sensor did not
> have to be close to or part of the drive train)
Do you find any situations where you have to space the gears out so the
chain fits tightly and snugly instead of slackening and introducing chain
backlash? One problem I did encounter with chain elements in particular was
their tendency to slacken off unless you found the right combination of
distance and gearing to put them at.
> > The reason I'm asking is I'd like to get some
> > comments on the feasibility of
> > asking LEGO to return these much-needed pieces to
> > Technic Acessory packs so
> > people can buy them, and I'd like to find out what
> > ideal quantities people
> > would like to see them available in.
>
> I'd like to see them available in quantities that
> equate to the length of the tractor treads that come
> in Mindstorms kits. (about 10 inches) That way you get
> a reasonable length, and can easily purchase in that
> quantity. I would buy a bucket full if the chain links
> were in the under 5 cent per link range (20+ for $1
> USD), and/or the conveyor links were in the under 16
> cent per link range (7+ for $1 USD).
That sounds like a good start, of course by buying extra packs one could
extend the treads as needed. As for the price range I agree fully, but it
may come down in the end to what price LEGO can manufacture and sell them
for.
> > I'd also like
> > comments on whether they
> > could be included with particular types of gear
> > wheel and axle, improved in
> > some way to make them do their intended function
> > better, and anything else I
> > may not have thought of.
>
> I would like to see specialty packs of parts. I don't
> know what the value of manufacture cost vs. sales
> would be, but if the chain link packs came with a 16
> and 24 gears that are specially made to mount to
> standard or mini/micro servo output shafts, it would
> allow for easy inclusion of precision movements to
> LEGO creations. Perhaps that is just better for 3rd
> party? I'd sure use them. I know servo motors are not
> LEGO, but I'd like to see LEGO servo motors too!
Well, I think if you just put an axle into the micromotor drive element, and
join it together with the standard chain and gear elements, you can already
achieve that effect. I don't see any need for 3rd party manufacturing yet.
As for the servo motors, yes that would be a nice idea, perhaps LEGO can
build their own design up, or adapt a pre-existing design to suit their
needs.
The difficulty with servo motors, though, is that they're going to need a
whole lot of on/off pulses as servo motors by their definition do tend to
move one step or part of rotational cycle at a time. I also understand
there are models out there that come with inbuilt position and rotational
sensors.
> It might also be possible for LEGO to manufacture
> add-on pieces that clip to the chain crossbars of one
> or more links for creating things like the GBC ball
> elevators etc. The chain links and treads are already
> a bit fiddly, so I don't think this would necessarily
> complicate the use of the chain parts.
It'd certainly be interesting to see what molds they can adapt or cut to
match properly with a 1x4 plate base sized footprint. As has been said
elsewhere in this thread, some way of improving the gripping power would be
nice. If they could be made to fairly easily hold onto a shrunken bucket
piece of some design I think something would definitely be possible.
> As I said, using chain, (one, maybe two per drive
> train) removes the backlash seen when using gears
> only. I have used a combination of Technic chain links
> with the conveyor belt links to create a linear
> movement along the flat side of the chain movement.
> Much like the GBC conveyors but with a movement of
> backwards and forwards to produce a linear movement
> overall by attaching bricks to the conveyor links.
I know one can with the proper ratio of chain links to gears, introduce gear
reduction with chain elements, by making them drive different sized gears.
I'm not sure of the exact ratios, but I think one could drive a 24-tooth to
a 40-tooth gear without much trouble. However, I do believe there is a
limit to what gear reduction is possible, as the chain will always drive the
same amount of gear ratio based on the size differences.
> > I know these are currently available as educational
> > spares packs, but the
> > quantity in particular of the Technic Link Tread
> > concerns me, people do like
> > to make tracked vehicles and $10 for 36 seems quite
> > expensive. I'd also
> > like to know if people would like to see the
> > aforementioned types of links
> > in a color other than black. I would say a bright
> > color, like blue or
> > yellow would be good, or perhaps even a transparent
> > link color could be
> > used.
>
> Black is fine for me. Axles are black (in my
> inventory) so black chain works fine.
Yeah, there is a plethora of colors available though, and I was wondering to
myself if anyone thought they'd seen another color they'd like to see the
chain links in. I do appreciate the comments though, as it would be nice to
see there is demand in another color for them.
> > So if you build in Technic, and use or want to use
> > these, then I'd like to
> > hear your comments so they can be put together in a
> > request for LEGO to make
> > them available as Technic Accessory packs, and
> > hopefully with new
> > assortments and colors.
>
> I'd like to see specialty drive chain packs, for both
> chain and tread links, and that hopefully include
> things like the gears that mount to servo motor output
> shafts. Perhaps an easy to use spring loaded idler
> gear that is one beam width wide.
That would be nice, we do have freewheeling gears - the ones used in stuff
like the 8880 and 8480 gear drives, and a problem with them is one needs
about 3-4 studs of width to accomodate them and the associated switching
gears/parts.
I certainly appreciate your feedback, it has been most helpful and
informative.
Cheers ...
Geoffrey Hyde
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