Subject:
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Re: Yet Another Technic Creation
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Newsgroups:
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lugnet.technic
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Date:
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Sun, 6 May 2001 02:06:55 GMT
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Viewed:
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2671 times
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"Jennifer Clark" <jen@vulture.dmem.strath.ac.uk> wrote in message
news:3AF2C178.8B3C2311@vulture.dmem.strath.ac.uk...
> Geoffrey Hyde wrote:
>
> > Hmm - I'm not sure, but I think sometimes demolition material can get
> > overbalanced somewhat. If the heavier stuff winds up at the wrong end, • it
> > can make lifting on a bit melodramatic, but like all things mechanical, • it's
> > just a matter of where the lever, fulcrum, and load are. :-)
>
> I saw this once, although the heavy material was all over to one side • causing
> the truck to lean over in a most precarious fashion. I assume these • vehicles
> are a lot more stable than they look in those situations...
Yeah, visually it's a bit unsteady looking.
> > As you can probably tell, those hydraulic pistons on the prototype are • quite
> > powerful - I'm not sure how much weight they can lift,
>
> I think the skips on 8x4s generally go up to about 20 (UK) tons, although • I am
> not sure if this is the gross or payload weight. I had some stats • somewhere
> about the pressure in the hydraulic system and it was indeed pretty
serious.
I imagine they would have some kind of overload protection too. It's not
unheard of for a hydraulic hose to break, especially if left poorly
maintained.
> > For some dumpsters, the driver of the truck will often get underneath • and
> > secure some chains to attachment points, I guess this is a safety • measure in
> > case the dumpster bounces around a bit, and moves off it's loaded • position.
>
> I have read that some of them have some kind of chassis locks as well, in • fact
> I believe some form of securing the skip to the chassis in addition to the • hook
> lift system is mandatory. I wish I had kept all these URLs!
Interesting, I do know that the hook usually stays connected to the dumpster
on the prototype.
> > They also use chains in cases where the dumpster has been moved into a
> > position where the hook can't reach it. They simply hook some chains • up,
> > and drag it to where the hook can engage properly, then loading goes as
> > normal. I'm not sure if this is mentioned on your site.
>
> It isn't, but I could perhaps rig up a photo to illustrate it - I have a • small
> grey chain which came with one of the newer "town" digger sets I received • at
> Christmas which should do the job ;-)
Careful! I'm not sure if they would actually pull any real weight before
cracking a link and snapping, rendering them useless.
One thing I'm interested in is how they mold those miniature chain links -
presumably they are lying in a set formation in a mold, and are
interconnected during the molding process itself then the interconnections
are cut off and voila a chain is ready.
> > One model I would like to see from the waste haulage and disposal side • of
> > things is the kind where they use a large dump truck with large liftarms
>
> Am I barking up the wrong tree here, or is the alternative model to the • airtech
> claw rig a variation on this theme?
Somewhat similar, but with considerable variation, and I was thinking to
myself, one could easily do it in pneumatics!
The waste trucks have three basic actions:
1. The obvious first one, lifting the bin up into position ready to empty
into the back of the truck.
2. Tipping it into the truck, surprisingly this is done with conventional
short length cylinders - probably could be easily modeled with short
pneumatic elements.
3. Horizontally sliding forks which can be adjusted for any size of
industrial refuse bin.
Apart from that, the only other thing one could model in them is a tipping
and compacting rear section, although that begins to get expensive in LEGO,
and mildly expensive in number of pneumatic elements needed. I suppose they
could be motorized, but it seems a shame, sometimes, to take the easy route.
;-)
--
Cheers ...
Geoffrey Hyde
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Message has 1 Reply:
 | | Re: Yet Another Technic Creation
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| (...) Ok, I can finally lay this ghost to rest: I had a look at the technical data section of the MAN website, where they have information on fitting tippers, hook lifts and so on to the chassis of their trucks, and they were quite clear that the (...) (24 years ago, 8-May-01, to lugnet.technic)
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Message is in Reply To:
| | Re: Yet Another Technic Creation
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| (...) I saw this once, although the heavy material was all over to one side causing the truck to lean over in a most precarious fashion. I assume these vehicles are a lot more stable than they look in those situations... (...) I think the skips on (...) (24 years ago, 4-May-01, to lugnet.technic)
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