Re: [PSUBS-MAILIST] manipulator

[VBra676539@aol.com]

Dan and Pierre,

There are control issues with the "backhoe" kind of design you are talking 
about. Remember that the more the thing weighs, the jerkier it is. This is not 
important the first time you get it to move, but it sucks when you are trying 
to get something done. If you doubt it, watch Don Liberatore from Harbor Branch 
try to grab a moving sample with their old arm (rate controlled) stuck on the 
front of 14 tons of submarine. The Galapagos trip had several examples. 

Consider a simple arm, pivot and rotate at the shoulder joint, and a claw 
open and close. If you want to get fancy, add a telescope section to the middle 
of it. There are dirt simple ways to make that work. Phil Nuytton built a 3-way 
arm for that little 1-man thing (I forget its name, not the Deepworkers), The 
air vents inboard through a 3-way valve, pretty much like the old HYCO main 
ballast vent valves, That's speculation, as it has been awhile since I saw the 
thing. But it was done with SS pneumo cylinders and flex tubing--about as 
cheap as you can get.

For hydraulics, you have to carry a pump, then valve the fluid. Parker 
Hannifin (among others) has a lot of that stuff, but it ain't cheap. Surplus 
cylinders and valves tend to be Russian tractor grade (read massive). Then there are 
some really nice little electro-hydraulic packages and electric solenoid 
valves (Parker again).

Look at the arm on the front of the Diaphus (PC-14) in Frank's book. That was 
a square one, and as far as I know is still working.

Vance



************************************************************************
************************************************************************
************************************************************************
The personal submersibles mailing list complies with the US Federal
CAN-SPAM Act of 2003.  Your email address appears in our database
because either you, or someone you know, requested you receive messages
from our organization.

If you want to be removed from this mailing list simply click on the
link below or send a blank email message to:
	removeme-personal_submersibles@psubs.org

Removal of your email address from this mailing list occurs by an
automated process and should be complete within five minutes of receipt
of your request.

mailto:removeme-personal_submersibles@psubs.org

PSUBS.ORG
PO Box 311
Weare, NH  03281
603-529-1100
************************************************************************
************************************************************************
************************************************************************