[PSUBS-MAILIST] Manipulators

Mon Jan 27 07:58:01 EST 2014

Oil compensated drill motor is a good idea. I have been trying to design a manipulator for Trustworthy. 
Thanks,
Scott Waters

Sent from my U.S. Cellular© SmartphonePhil Nuytten <phil at philnuytten.com> wrote:There is no movement of the air pistons when they are not in use – that is, there is no air in the pistons once you exhaust the pressurization air back into the one atmosphere cabin. The pistons are then dead-headed until you energize them again. Note that this simple little system is designed to be used while the sub is on the bottom. I have used it up off bottom but it gets pretty busy maintaining position by VBT or upthrust and operating the manip valves at the same time.
If you really want to go ultracheap on an electric manip, buy a reversible dc electric drill, stick it in a thin walled tube, fill it with oil, set it on slow and use the rotation to operate a rack and pinion system which gives you a lineal movement like a piston  (run the rotary shaft through a camera case  style o ring gland or an imperial tubing fitting or a  swagelock style compression fitting with an oring or teflon ring substitiuting for the  compression olive or the metal compression ring)– rack and pinion all stay out side in the water. We built several of these to use with a small ROV and it worked OK – (also used two drill motors for propulsion  on the ROV!)
Phil

From: Alan James
Sent: Sunday, January 26, 2014 2:48 PM
To: Personal Submersibles General Discussion
Subject: Re: [PSUBS-MAILIST] Manipulators

Thanks Phil, great system description.
I tried Googling for the sea urchin manipulator but couldn't even find the Sea Urchin.
Would appreciate seeing any pictures of it.
One question. How do you counter the variations in pressure as you dive & ascend
from causing the cylinders piston to move in & out or do you just live with this?
From the frustration I've heard from K boat builders through ambiguities in the plans,
dangerous elements in the design (hard ballast tank) & antiquated parts, it might be timely to
ditch the Kitrege plans & replace them.  But I might get shot for saying that.
Alan

From: Phil Nuytten <phil at philnuytten.com>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Sent: Monday, January 20, 2014 9:52  AM
Subject: Re: [PSUBS-MAILIST] Manipulators

Yes, as Vance says we did work up a pneumatic manip for the original ‘Sea Urchin’ sub. The design criteria was: brute simple, three functions (extend/retract, swing 90 degrees each side/ jaw open/close) and, above all, CHEAP!! we used air cylinders, plastic tubing and three-way valves – one for each function. The valves exhausted back into the sub cabin. The system pressure was about 200 psi, as I recall, and the manip was operated independently from a scuba pony tank mounted outside for that purpose. System  pressure was kept at 200 psi over bottom, regardless of depth  by the first stage of a scuba regulator with the spring shimmed to 200 psi and the reg yoked to the tank in the usual fashion. Very simple system and it worked well – the exhaust into the cabin was so small as to cause only a slight increase in cabin pressure because the piston area is only a couple of square inches. Over pressure on a move into shallower water was avoided by a circle-seal non-return vent valve – same one used to suck a vacuum on the sub before diving.
I have some pretty good pictures of the manip on Sea Urchin which I’ll try to dig up and post. Speaking of Sea Urchin, I have often toyed with the the idea of putting out a  Sea Urchin Kit – ala Kitteridge - but don’t know how much interest there would be.
Phil

From: Alan James
Sent: Sunday, January 26, 2014 11:54 AM
To: Personal Submersibles General Discussion
Subject: Re: [PSUBS-MAILIST] Manipulators

Here is a great looking manipulator for .31c US.
Not sure what the postage is from Poland. I tried the "buy now" on another link but
couldn't initiate a purchase.
http://http://robosklep.eu/sklep/pl/p/Hydraulic-Arm/231
Alan

From: Alan James <alanlindsayjames at yahoo.com>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Sent: Saturday, January 25, 2014 1:20 PM
Subject: Re: [PSUBS-MAILIST] Manipulators

Thanks Vance,
I'll have a look in to the pneumatic manipulator; however there are problems
that come to mind, like how do you stop the whole unit going in & out like a concertina
with water pressure changes.
Alan

From: "vbra676539 at aol.com" <vbra676539 at aol.com>
To: personal_submersibles at psubs.org 
Sent: Saturday, January 25, 2014 10:50 AM
Subject: Re: [PSUBS-MAILIST] Manipulators

I can't answer, as I have precisely zero experience with pneumo manips. Nuytco did in fact cook one up for the Sea Urchin, which seemed to work okay, but I don't know anything about it. Sorry. That said, if it's cheap and it works (even if it's a pain in the ass) then it's worth having. Subs should be able to DO something, not just cruise around like an oversized camera housing with motors. I'd give serious consideration to the ball and socket arm, which functions adequately down to about 600 feet (according to the boys who have used them). We figure one would cost about $500-600 USD to machine, plus material and welding. A thousand bucks or a little more isn't bad, considering there are exactly three moving parts in the whole  thing (as opposed to a hydraulic system which has about 3 moving parts to the running inch).
Vance

-----Original Message-----
From: Alan <alanlindsayjames at yahoo.com>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Sent: Fri, Jan 24, 2014 3:12 pm
Subject: Re: [PSUBS-MAILIST] Manipulators

One more question Vance & I'll leave you in peace
for a week.
For a small non commercial submersible operating to 500 ft
that has a very limited use for a manipulator other than it being there
just in case we come across some item of value. Is a pneumatic manipulator a good
option? Air is already there & wouldn't be consumed much because
of the limited use. No noise & expensive space consuming hydraulic system.
And as you say there are options for lifting heavier items.
Thanks,
Alan

Sent from my iPad

On 25/01/2014, at 8:01 am, Joe Perkel <josephperkel at yahoo.com> wrote:

I particularly liked the PVC tube with the furled lift bag and air source, now that's got real "get work done" utility.

It seems to me that a permanently mounted air source terminating just aft of the claw is a natural companion set-up for anyone with a manipulator on a PSUB. 

Joe

Sent from Yahoo Mail for iPad

From: Alan James <alanlindsayjames at yahoo.com>;    
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>; 
Subject: Re: [PSUBS-MAILIST] Manipulators 
Sent: Fri, Jan 24, 2014 6:09:42 PM 

Thanks Vance,
that's shed some light on the subject.
Alan

From: Vance Bradley <Vbra676539 at AOL.com>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
Sent: Saturday, January 25, 2014 5:42 AM
Subject: Re: [PSUBS-MAILIST] Manipulators

Alan,
I've seen the discussion. The smallest sub I know of with a manipulator on board is the Deepworker. No exfra tanks there. Metacentric vs CG works in all directions. Yes, you get movement and no it's not a problem in my experience. I did operate the bigger subs but also smaller ones, to include Aquarius, briefly in a DW, plus three different K-boats, so speak with some experience. You put everything you imagine on a small sub, you get a big sub. In any case, It's probably best to think of a psub as a work in progress. Get the boat done, go play, scratch head, get more work done, go play, scratch head......and so it goes.
Vance

Sent from my iPhone

On Jan 24, 2014, at 3:20 AM, Alan James <alanlindsayjames at yahoo.com> wrote:

Vance,
a couple of people have mentioned lately the problem of the shifting of
balance as you reach out with a manipulator & have talked about countering it with
trim tanks. Is it a big deal if you go nose down, tail up? Possibly more of a problem working on a
vertical face than picking something up off the bottom.
Some of our subs will be a lot smaller than the working subs you were in so the problem would be
accentuated in our case.
Can you give us some of your experience on this thanks & in your opinion is it worth messing
about with the trim while operating the manipulator.
Alan

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