In a message dated 4/28/2005 1:28:12 PM Eastern Standard Time, satch@...
writes:
Bill Jonesi has directed us to the "Navichron" clock (cheaper than a Heuer
Sebring, anyway!). I wonder if any Halda geeks on this list know anything
about a strange black box that Rusty Link installed in my Saab 96 over
thirty years ago (along with his Halda Twinmaster): this box had two cable
connections, one coming in from the dead-wheel drive and the other going out
to the Twinmaster.

Inside the box was something called a ball-disc integrator, and the front of
the box had a vernier dial. Its purpose was to adjust the relationship of
the incoming and outgoing cable speeds, giving you infinite adjustment of
Halda. No swapping of X and Y gears! Pinpoint accuracy!

Link, of course, does not remember exactly where it came from, and I've
never encountered another like it. Anybody ever see one of these or know
anything about it?

Satch Carlson
Team AFRICA
Satch,

How you doing up there? Been a while!

Anyway, relative to your topic, yes these mechanical variable ratio devices
used to be fairly common in the process control industry as well as some old
machine tools.

There were two different designs, one which had a "ball" which could be moved
down the length of a cone. One side, usually the cone, was the input shaft
and the ball end was the output shaft. Depending upon where you positioned the
ball via a mechanical screw adjustment, it would ride around the cone at what
would be a certain circumference.

To change the ratio up or down the adjustment shaft would in essence move the
ball to the "fatter" end of the cone in order to make the ratio go in one
direction and to the "pointy" end of the cone to make the ratio go the other
way.


The design you have (disk/ball) is the one which was mechanically more
complicated, although not much more. The disk could be positioned at the
"equator"
of the ball for a ratio of unity, and could be moved to the north pole of the
ball for making the output shaft turn fewer turns for a given input shaft. In
reality the "one to one" point was, by using different diameter disks, made
at the 45 degree north latitude position for models which needed a +/- ratio
available. Usually the ball was the input end of the shaft and the disk the
output.

Also, most of the designs did not actually have a full "sphere" as the ball
inside but rather a hemisphere since mathematically there was nothing to be
gained by having the ability to adjust in the "southern" hemisphere of the
arrangement.

Similar principal for the ball/cone models that for rally use usually had the
unity ratio a little less than halfway up the cone, since the "tip" of the
cone was really not a workable position to use.

Anyway, these were also used in some older mechanical aircraft instruments,
although even when I had my single engine pilot license I never personally saw
the "guts" of an instrument which actually had one. I was told by an old
timer that they were used in there somewhere...

In fact, there was a chap in Toronto who used to sell these things specially
packaged for rally use and they worked great. When I ran with Iain he always
had one installed in the car usually either to his Halda/Speedpilot setup or
internally via the Langwell odometer he used, which accomplished the same task
with a slightly more compact design of infinite ratio input to output shaft
adjustments.

Some of the later Halda Speedpilots (maybe the MkX or something) had an
option which likewise did offer a limited range of infinite adjustment but I
don't
recall the details of that design but I seem to recall it was a ball/cone type
deal, albiet in a modified execution. I had Martin rebuild mine so never
took them apart myself.

Do you remember exactly what the little blob you used in ths Saab looked
like? I presume like everything else of the period it was crinkle black in
color,
but I do have some recollections of the setup Iain had.

I had a ball/cone one installed in one of my really early rally cars (...get
ready...) a 1965 Mustang Coupe, but to make it work in a worthwhile manner I
still had to use one of the little inline adjustable plastic gearboxes that
Gene sold in order to get the total number of rev's/mile down to a number that
made sense for the ball and cone. The big problem was that if you got too crazy
with the RPM of the cables, the disk would slip on the cone (or ball) and
unfortunately damage the rubber coating that was there, thus making the setup
suitable for the trash bin. Fortunately when I used to buy these things there
was an Army/Navy surplus joint in Syracuse where I could get plenty of spares...
only fabrication was to cobble something up for the end to convert the fat
keyed shaft into the more typical speedo cable of the day. I must admit that I
don't know what happened to them all since between busted ones and "surplus"
spares I probably had a dozen or so of them... the corrected cable originally
went to a microswitch creating a contact closure for a 12VDC Veeder-Root
resettable electromechanical counter that we used for odometer readouts of the
corrected official miles. I still have those, and even the microswitch setup,
but
the ball and cone things are gone.

Take care and hope our paths cross soon...

Regards,
Walt Kammer


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