Subject:
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Re: clutches
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Newsgroups:
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lugnet.technic
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Date:
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Mon, 1 Aug 2005 01:14:34 GMT
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In lugnet.technic, Vineet Honkan wrote:
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I saw on some sites a pic of a lego clutch using the newer double bevel gears.
This is basically the same type of clutch system used in earlier technic car
sets (8860, 8865) and I was wondering, since those clutches used to jam (the
gears couldn’t move smoothly) would the same happen here in the newer clutch?
Thanks.
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Lego have never made a clutch (correct me if im wrong and i don’t consider this
to be a
“clutch”
) so i’ll assume you are reffering to the gearbox.
The beauty of the older style gearboxes (and what made them work) was the fact
that the teeth on non-beveled gears (like
this) are less than 1stud
wide.
this allows the gear to disengage from one gear partner completely before
meshing with the next; all within 1 stud length of gearshift. If the gear was
partially meshed with two different ratios, the drive train would come to a
stop, and you may strip teeth.
As the double bevel gears are almost 1 stud wide, the spacing between gears
would have to be tweaked so that when shifting, the gear doesn’t mesh into two
different partners, hence the shift length may need to be legnthend out to about
1.5studs maybe 2studs ???? too complicated and too big.
Once this was overcome, the problem of crunching would have to be looked at.
The crunching problem with the older kits gears was mitigated by keeping the
gearbox rolling, ie, the car would have to be in motion.
The newer style gear boxes in the 8880 or 8448 are still susseptible to
crunching, but much less likely as the driving
ring only has four teeth
on the inside where it engages, which is why there is transmittion lag after
changing gears esspecially noticible on the 8421.
The newer double bevel gears will have the same crunch problem as the older
style boxes but less obvious/common, but again can be overcome with motion.
The crunching only occurs when the teeth of two or more gears meet but not mesh.
the likelhood of meshing to occur will be proportional to the amount of vacant
teeth space on the gear. less teeth = less chance of crunch. more teeth = more
crunch.
If the teeth on the beveled gears were completely beveled and the sides of the
teeth were not flat, likelyhood of crunch would be very little. (but they are
not)
In short all LEGO sets produced to date with gear selectors are susseptible to
crunching in some amount.
Steve
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Message has 1 Reply:
 | | Re: clutches
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| (...) What about this (URL) ? I have successfully used that in applications requiring a clutch - in fact an elaborate multiplexer with a worm gear, two has bushes and two of these clutches. They do still crunch - but much less so than some other (...) (19 years ago, 1-Aug-05, to lugnet.technic)
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Message is in Reply To:
| | clutches
|
| I saw on some sites a pic of a lego clutch using the newer double bevel gears. This is basically the same type of clutch system used in earlier technic car sets (8860, 8865) and I was wondering, since those clutches used to jam (the gears couldn't (...) (19 years ago, 31-Jul-05, to lugnet.technic)
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