[PSUBS-MAILIST] cue ball arm

[Stephen Fordyce via Personal_Submersibles]

Hi Hank,
Instead of an air cylinder with pneumatic supply, what about a small
hydraulic cylinder powered by the pressure outside? If you match the cross
sectional area of the rod through cue ball and the hydraulic cylinder (I
guess it would be the top end, so have to subtract hydraulic rod area from
piston area) it should be more or less self compensating at any depth.

Fair amount of messing around to do it with maybe an oil bladder outside,
through-hull, etc., but saves you having to deal with increased cabin
pressure due to release of spent air from the pneumatic system, especially
if you're adjusting a lot.

Cheers,
Steve
On 30/11/2014 5:52 AM, "hank pronk via Personal_Submersibles" <
personal_submersibles at psubs.org> wrote:

Alan,
Have a look at my cue ball arm assembly at Gamma restoration.  I repaired
the original seat for the cue ball.  After Hugh said to forget about making
a curved seat, I realized I could make my own seat on a 45 degree angle.  I
made the second half of the assembly with a home made plastic seat machined
from ABS.  I installed it in Gamma and it turns smooth as glass and has the
original amount of range.  With home made plastic seats, it is a breeze to
make this because the o-ring still does the sealing.
Now I just need the plans and my new cue ball to finish the arm.
Vance,
I was thinking about mounting an air cylinder horizontal inside the sub to
pull on the block and tackle cable.  The deeper I go the more air pressure
I add, it will be like an adjustable spring.
Hank
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