[PSUBS-MAILIST] Manipulators

Thu Jan 23 21:51:23 EST 2014

Alan,
All good points as well.  I know I'm not going to try to develop and modify the components myself on whatever system I end up with.  Rather I expect to take what has already been proven and incorporate it.  Ideally that will mean getting a complete system off the shelf  unless it is just too expensive.
Jim

-----Original Message-----
From: Alan James <alanlindsayjames at yahoo.com>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Sent: Thu, Jan 23, 2014 8:28 pm
Subject: Re: [PSUBS-MAILIST] Manipulators

Jim,
I had a lot of discussion with a previous member, Frank Dalgleish, about using linear
actuators underwater.  Frank has since passed on.
I ended up with about 8 actuators & pulled a few to bits to try & compensate them.
One of the problems I encountered was that the small motors didn't like the compensating
oil & had what Phil describes as a "herky jerky" movement caused by the brushes being
flung off the commutator by the centrifugal force of the oil. On bigger motors it wouldn't be
such a problem & the spring tension can be changed to compensate, but the small motors
are generally a sealed unit. I had to drill the motor casing to inject oil in to them.
Aside from that; with the piston moving in & out, it is displacing the compensating oil, &
you need a flexible external bag for both this & to maintain the internal pressure at ambient.  
Obviously someone has got it right by the link you posted. (posted a link to that a few years back)
You could perfect it, but I think it would be more trouble than its worth as you end up with
something like a hydraulic cylinder anyway except with a hydraulic system you have one motor
for all the cylinders, whereas with linear actuators you have one motor per cylinder.
Cliff replaced his hydraulic cylinders with actuators but they caused him grief at conference.
He may want to comment.
Hope that saved you 200 hrs of research.
Alan

   From: "jimtoddpsub at aol.com" <jimtoddpsub at aol.com>
 To: personal_submersibles at psubs.org 
 Sent: Friday, January 24, 2014 2:17 PM
 Subject: [PSUBS-MAILIST] Manipulators

Vance, Hank,

Moving the thread title back to Manipulators:  My intention has been to buy or build an all-electric manipulator instead of hydraulic or pneumatic.  Do you have any thoughts on that?  Here's one I found online last year:
http://www.youtube.com/watch?v=uY0Qz-CxkBE

Thanks,
Jim

-----Original Message-----
From: Land N Sea <landnsea1 at hawaiiantel.net>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Sent: Thu, Jan 23, 2014 6:54 pm
Subject: Re: [PSUBS-MAILIST] I am not a dork

Hank,
I was under the impression that pneumatics loose their punch with depth and that is why people usually go with hydraulics? 

Rick

From: hank pronk 
Sent: Thursday, January 23, 2014 2:43 PM
To: Personal Submersibles General Discussion 
Subject: Re: [PSUBS-MAILIST] I am not a dork

Rick,
The cylinders are pneumatic but you can use hydraulic if they use an o-ring for the shaft seal.  
Hank  

On Thursday, January 23, 2014 5:36:58 PM, Land N Sea <landnsea1 at hawaiiantel.net> wrote:

Hank,

Do you have any data on the rams that you have and they are hydraulic and not pneumatic correct?

Rick

From: hank pronk 
Sent: Thursday, January 23, 2014 2:12 PM
To: Personal Submersibles General Discussion 
Subject: Re: [PSUBS-MAILIST] I am not a dork

Rick,
The nice thing about a manipulator for a sub is, you want it to be slow and slow is cheap.  Go with big cylinders and a small pump with a restrictor.  It will be so easy to operate it you won't believe it.
Hank

On Thursday, January 23, 2014 4:57:21 PM, Land N Sea <landnsea1 at hawaiiantel.net> wrote:

Most of what I plan to use the arm for is for gathering all the gold doubloons that fell out of Captain Cooks pockets while he was here in Kealakekua bay wind surfing, but I would settle for an old bottle or two off his ship if I had to. I was more wondering if I came across an abandoned small anchor or something else that weighed around 50 Lb.'s or so if it would up end the boat much? I would rather not use the forward MBT to keep the trim because of having to dump air at the proper rate while ascending. Tagging it with a line and letting the guys in the support boat lift it also sounds good but I would have to master the manip technique. 

Rick

From: Vance Bradley 
Sent: Thursday, January 23, 2014 11:20 AM
To: Personal Submersibles General Discussion 
Subject: Re: [PSUBS-MAILIST] I am not a dork

Manips are for manipulating, not lifting. Most light arms can do 50-60#. for lifting you could hook on a (releasable) cables and lift with the MBTs. Better yet, take a line down to attach and let your surface crew haul away, or do what we fit at HBOI and in the North Sea. Take a lift bag down rolled into a PVC tube with a blow and go hose from your air banks. Hook up, back away to deploy the bag, inflate and run away (to get out from under the load)
Vance

Sent from my iPhone

On Jan 23, 2014, at 2:27 PM, "Land N Sea" <landnsea1 at hawaiiantel.net> wrote:

I am planning on fabricating my own manipulator for my K-350 that will be   hydraulic and was wondering if anybody that had experience using one on a boat   that size would be able to let me know about how much an arm would be able to   pick fully extended and if a VBT up forward was mandatory to keep the   trim.

I am planning on making the manipulator out of two sections, each about   2’ long giving me a 4’ reach fully extended which will get me out just past my   forward MBT. 

I realize that the lifting capacity is based on a number of things like   the rated capacity of the rams and where they are attached to the arms so if   you know that as well that would be great. It’s freezing here on the big   Island! I woke up to a chilling 54 degrees and had to put on a sweat shirt   just to walk up to my shop.<wlEmoticon-sadsmile[1].png>

Rick 

From: hank pronk 

Sent: Wednesday, January 22, 2014 1:43 PM

To: Personal   Submersibles General Discussion 

Subject: Re: [PSUBS-MAILIST] I am not a dork

Alan,

Yes I could spring load it, It does take some effort to pull the   fingers open.  The oil has to travel through a pretty small line and all   I have here is a pail of 5/30 and that is a bit heavy.  I don't heat my   shop at night so it gets chilly by morning.

Hank

On Wednesday, January 22, 2014 4:34:35   PM, Alan James <alanlindsayjames at yahoo.com>   wrote:

Hank,

can you mount   a wedge somewhere so you can push the manipulator grippers up   against

it to wedge   them open? Or have a compression spring temporarily mounted across the   grippers?

     You could hang some plastic fish from the garage roof  to add a bit of   realism.

Alan

From: "vbra676539 at aol.com" <vbra676539 at aol.com>
To: personal_submersibles at psubs.org   
Sent: Thursday,   January 23, 2014 11:09 AM
Subject: Re: [PSUBS-MAILIST] I am not a   dork

Hey, she's a banker. It's all black   or white with them. Except for the ones with mad manibubators in the shop out   back, one supposes.

-----Original   Message-----
From: hank pronk <hanker_20032000 at yahoo.ca>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Sent: Wed, Jan 22, 2014 4:37 pm
Subject: Re:   [PSUBS-MAILIST] I am not a dork

The only problem is, Gamma's manipulator has a power only to close   gripper.  The gripper opens with outside water pressure pushing against   it.  So I have to jump out of the sub to open the gripper each   time.  I was trying to explain this to my wife and she replied "can't you   just put it in a pail of water"  I am still laughing inside of coarse   :-)

Hank

On Wednesday, January 22, 2014 2:03:46   PM, Michael Holt <mholt at ohiohills.com> wrote:

On 1/22/2014 2:57 PM, Alec Smyth   wrote:
> That is indeed a very necessary practice, but for it   to work properly 
> you also have to make loud "AOUUUUUGAH"   klaxon sounds every so often, 
> to indicate diving and   surfacing!
You're right: you gotta have the right sounds.    I have a friend who used 
to sit in the incomplete fuselage of   his biplane in his garage, making 
airplane-engine noises.

M

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