🚀 go-pugleaf

In article <10878@ucbvax.BERKELEY.EDU> carvalho@ucbvax.BERKELEY.EDU (Marcio de Carvalho) writes:
>
>	Have anyone heard about this so-called continuous
>transmission? ...
>	As it was described to me, it is basically a pair of
>controllable variable diameter wheels linked by a belt; which
>enables the driver to choose among any of the infinitely many 
>transmission ratio possible.

These things have been promoted as something new, but my mother had a 1963 
(nineteen sixty-three) DAF with one of those transmissions.  The car, about
the size of a VW Bug, had a 2 opposed cylinder, 30HP, air cooled front engine
with a centrifugal clutch, with the transmission in the rear.  By having two
belts, one for each wheel, no differential was needed, and the resulting
"limited slip" operation make it fantastic on snow and ice. But the car had
many problems, mostly related to the transmission.  (BTW, the cars basic
model sold for about $1200, making it one of the cheapest cars available at
the time, and by far the cheapest with an automatic transmission which at the
time was only available on very few small cars).

1. Belt life was limited to about 8-10k miles.  While the car could be driven
   with one belt missing, it would slip so much that you wouldn't dare stop
   on a hill.

2. Belt slippage was a problem, especially when wet.

3. Performance was awful, even compared with contemporary small cars.  Top
   speed was about 60, and acceleration was  worse than the 40hp VW Buses
   of the time!  Gas mileage was about 30-32 in suburban driving.  This car
   was no match at all for the popular VW Bugs and Renault Dauphines of the
   time.

4. The transmission (Forward--Neutral--Reverse) had to be shifted swiftly
   between F and R.  Because of the lack of a manual clutch if you stopped
   in N you couldn't shift it into gear.  In this situation you had to turn
   the engine off, wait about 10 seconds for the driveshaft to stop spinning,
   put it in gear and restart (YES, you always started the car in gear!).

To be fair, I am sure they improved things over the years.  After they
stopped importing them in the late 60s, DAF switched to a more powerful 4
cylinder engine.  The company was purchased by Volvo a few years
ago, and the cars are now sold under the Volvo name in Europe.  I may need
to be corrected on this last statement, since I am not sure.

Tom Almy

> 
> 	As it was described to me, it is basically a pair of
> controllable variable diameter wheels linked by a belt; which
> enables the driver to choose among any of the infinitely many 
> transmission ratio possible.
> 

	They used to have these on minibikes about 12 years ago.
You couldn't select for yourself the ratio as it was a function
of the engine/vehicle speed/throttle opening. Two centrifugally(sp?)
operated v-groove pulleys narrowed and widened to change the
overall drive ratio (when one pulley widened the other narrowed).
My minibike didn't have one and another kid's did. He always blew
me away since he always had the "perfect" gear for the occasion.

	To handle the output of a car I'm sure that the system
is quite different, but the result is the same: a perfect ratio
for all occasions!

	As far as revenge on the hotshoe with the belt drive, I
decided more top-end speed would help out. So I disabled the
governor on the ol' 3-h.p. Tecumseh. Really helped out the top-end
speed; the bottom-end of the engine came out the large hole in
the side of the block, however! A couple of years later who do
I see? Hotshoe in a 383 Road Runner! Well I figured...

                1			Stick-shifts forever,
              1   1
	    1   2   1			Doug Williams
	  1   3   3   1			AT&T Bell Labs
	1   4   6   4   1 		Reading, PA
      1   5   10  10   5   1		mhuxl!daw1
    1   6  15   20   15  6   1

When I was living in Italy (80-81) I seem to recall that Fiat was road testing
a bunch of Ritmos (Stradas in the US) with this kind of transmission. They
gave them to taxi drivers to see how they held up under tough conditions.

I don't think this is anything new, as some other (older) European cars* used
to have this kind of transmission - the problem was the belts would break
rather easily. The newer Fiats had steel belts which weren't supposed to 
break.

Alberto Segre
Coordinated Science Lab
Univ. of Illinois @ Urbana


* I think it was some Dutch manufacturer - is it DAP or something like that?

In article <340@tekchips.UUCP> toma@tekchips.UUCP (Tom Almy) writes:

>>	Have anyone heard about this so-called continuous
>>transmission? ...

>These things have been promoted as something new, but my mother had a 1963 
>(nineteen sixty-three) DAF with one of those transmissions.  The car, about
>the size of a VW Bug, had a 2 opposed cylinder, 30HP, air cooled front engine
>with a centrifugal clutch, with the transmission in the rear.  By having two
>belts, one for each wheel, no differential was needed, and the resulting
>"limited slip" operation make it fantastic on snow and ice. But the car had
>many problems, mostly related to the transmission.  (BTW, the cars basic
>model sold for about $1200, making it one of the cheapest cars available at
>the time, and by far the cheapest with an automatic transmission which at the
>time was only available on very few small cars).
>
>1. Belt life was limited to about 8-10k miles.  While the car could be driven
>   with one belt missing, it would slip so much that you wouldn't dare stop
>   on a hill.
>
>2. Belt slippage was a problem, especially when wet.
>
>3. Performance was awful, even compared with contemporary small cars.  Top
>   speed was about 60, and acceleration was  worse than the 40hp VW Buses
>   of the time!  Gas mileage was about 30-32 in suburban driving.  This car
>   was no match at all for the popular VW Bugs and Renault Dauphines of the
>   time.
>
>4. The transmission (Forward--Neutral--Reverse) had to be shifted swiftly
>   between F and R.  Because of the lack of a manual clutch if you stopped
>   in N you couldn't shift it into gear.  In this situation you had to turn
>   the engine off, wait about 10 seconds for the driveshaft to stop spinning,
>   put it in gear and restart (YES, you always started the car in gear!).
>
>To be fair, I am sure they improved things over the years.  After they
>stopped importing them in the late 60s, DAF switched to a more powerful 4
>cylinder engine.  The company was purchased by Volvo a few years
>ago, and the cars are now sold under the Volvo name in Europe.  I may need
>to be corrected on this last statement, since I am not sure.

You're actually very close.  Volvo indeed now manufactures CVT models
at the old DAF factory.  It's a different model, though, and is known
as a Volvo 343.  It's about the size of a Golf II, and is considerably
more civilized than an old DAF.  The transmission is still a
mechanic's nightmare, though.

VW and other companies are working on "second-generation" CVTs.


				   \tom haapanen
				   watmath!watdcsu!haapanen
Im all lost in the Supermarket
I can no longer shop happily
I came in here for that special offer
Guaranteed personality				 (c) The Clash, 1979

> 
> 	Have anyone heard about this so-called continuous
> transmission? According to some friends, a car equipped with
> one was presented in this year's Automobile show in Turin, 
> Italy. 
> 	As it was described to me, it is basically a pair of
> controllable variable diameter wheels linked by a belt; which
> enables the driver to choose among any of the infinitely many 
> transmission ratio possible.
> 	Any information would be helpful.
> 	Thanks,
> --Marcio
> 
> 	carvalho@ucb-vax.edu
> 	ucbvax!carvalho

*** REPLACE THIS LINE WITH YOUR MESSAGE ***
The type of transmission you have discribed has been used on farm equipment
for at least 25 years, especially large grain combines.  The system is 
composed of two variable diameter pulleys with a belt in between.  One 
pulley has a hydrolic cylinder attachment that controls its diameter
and the diameter of the second cylinder simply 'follows' the first
through a spring loaded arrangement.  The hydrolic system is under the control
of the operator.  

This system works quite well; at least the ones that I am familiar with did.
No maintenance was ever required, etc.  But they were huge; size was not a
serious factor on the side of a big piece of field equipment.  It is hard
for me to picture a manufacturer development anything like the above that
would fit in as small a space as our standard car transmissions.

-- 




				     Albert H. Spinks - 71BU072120

> > 
> > 	Have anyone heard about this so-called continuous
> > transmission? According to some friends, a car equipped with
> > one was presented in this year's Automobile show in Turin, 
> > Italy. 
> > 	As it was described to me, it is basically a pair of
> > controllable variable diameter wheels linked by a belt; which
> > enables the driver to choose among any of the infinitely many 
> > transmission ratio possible.
> > 	Any information would be helpful.
> > 	Thanks,
> > --Marcio
> > 
> > 	carvalho@ucb-vax.edu
> > 	ucbvax!carvalho
> 
> *** REPLACE THIS LINE WITH YOUR MESSAGE ***
> The type of transmission you have discribed has been used on farm equipment
> for at least 25 years, especially large grain combines.  The system is 
> composed of two variable diameter pulleys with a belt in between.  One 
> pulley has a hydrolic cylinder attachment that controls its diameter
> and the diameter of the second cylinder simply 'follows' the first
> through a spring loaded arrangement.  The hydrolic system is under the control
> of the operator.  
> 
> This system works quite well; at least the ones that I am familiar with did.
> No maintenance was ever required, etc.  But they were huge; size was not a
> serious factor on the side of a big piece of field equipment.  It is hard
> for me to picture a manufacturer development anything like the above that
> would fit in as small a space as our standard car transmissions.
> 
> -- 
> 
> 
> 
> 
> 				     Albert H. Spinks - 71BU072120

*** REPLACE THIS LINE WITH YOUR MESSAGE ***
hydraulic instead of hydrolic---sorry about that
-- 




				     Albert H. Spinks - 71BU072120

In article <923@burl.UUCP> ahs@burl.UUCP (Spinks Albert H. ) writes:
>> > 
>> > 	Have anyone heard about this so-called continuous
>> > transmission? According to some friends, a car equipped with
>> > one was presented in this year's Automobile show in Turin, 
>> > Italy. 
>> > 	As it was described to me, it is basically a pair of
>> > controllable variable diameter wheels linked by a belt; which
>> > enables the driver to choose among any of the infinitely many 
>> > transmission ratio possible.
>> > 	Any information would be helpful.
>> > 	Thanks,
>> > --Marcio
>> > 
>> > 	carvalho@ucb-vax.edu
>> > 	ucbvax!carvalho
>> 
>> *** REPLACE THIS LINE WITH YOUR MESSAGE ***
>> The type of transmission you have discribed has been used on farm equipment
>> for at least 25 years, especially large grain combines.  The system is 
>> composed of two variable diameter pulleys with a belt in between.  One 
>> pulley has a hydrolic cylinder attachment that controls its diameter
>> and the diameter of the second cylinder simply 'follows' the first
>> through a spring loaded arrangement.  The hydrolic system is under the control
>> of the operator.  
>> 
>> This system works quite well; at least the ones that I am familiar with did.
>> No maintenance was ever required, etc.  But they were huge; size was not a
>> serious factor on the side of a big piece of field equipment.  It is hard
>> for me to picture a manufacturer development anything like the above that
>> would fit in as small a space as our standard car transmissions.
>> 
I lived in England between 1970 and 1977.  Saw quite a few specimens of a
car with a continuous transmission.  It was called a DAF, and was made in
Holland.  Used a belt and cone pulleys.  I was told that the belt was no
more likely to break than an axle on a conventional drive.
-- 
Herb Kanner
Tymnet, Inc.
...!hplabs!oliveb!tymix!kanner